JP2007534483A - Nonwoven composite materials and related products and methods - Google Patents

Abstract

The present invention is directed, in one embodiment, to a catalytic substrate suitable for use as a substrate in many applications, such as catalytic converters. Another aspect of the present invention is a filtration substrate suitable for use as a substrate in many applications, for example, particle filters such as diesel particle filter (DPF) or diesel particle trap (DPT). The present invention also provides an improved substrate for removing and / or eliminating pollutants from combustion engine exhaust. The catalyst substrate and the filter substrate, in certain embodiments, provide an improvement in the removal of contaminants from the exhaust gas. Improvements may include one or more of the following: a faster ignition period, PM depth filtration, low back pressure, a low probability of clogging, in the exhaust system including the manifold or head itself Ability to be configured in many locations, high probability of catalytic reaction, high conversion ratio of NO _x , HC and CO, faster burning of PM, minimization of catalyst material usage, etc.

Description

  The present invention relates to substrates useful for catalyzing certain reactions and for filtering particulate matter, as well as related embodiments, such as the treatment of exhaust from internal combustion engines, and more particularly emissions. It relates to, but is not limited to, catalyst / substrate combinations useful for control and related methods, and related products and manufacturing methods.

Embodiments of the present invention described herein can improve the quality of the human environment by contributing to the restoration or maintenance of one or more basic life support natural factors such as air, water and / or soil. Is considered to be materially enhanced. The invention and its embodiments are described in further detail below in the Summary and Detailed Description section of the invention.

Exhaust, industrial and pollution Engines produce much of the power and mechanical action used throughout the globe. The internal combustion engine is probably the most widespread device because it is more efficient than that in external combustion engines such as traditional trains and steam ships. With an internal combustion engine, fuel combustion occurs internally. Such engines produce motion and power that can be used for any number of purposes. Examples include automobiles, locomotives, marine applications, recreational vehicles, tractors, building equipment, generators, power plants, manufacturing facilities, and industrial equipment. Fuels used to supply power to the internal combustion engine include, but are not limited to, gasoline, compressed gas, diesel, ethanol and vegetable oil. Due to the inherent inefficiencies in engine mechanisms and the fuel used to power them, emissions of various pollutants occur. Thus, while engines are a major innovation and benefit, the millions of engines used around the world today represent a substantial source of air pollution.

  There are two main types of pollutants produced by internal combustion engines: particles and non-particles. Particulate contamination is generally small solids and liquid particles. Examples include carbon-containing soot and ash, dust and other related particles. Non-particulate contaminants include gases and small molecules such as carbon monoxide, nitric oxide, sulfur oxide, unburned hydrocarbons and volatile organic compounds. Particulate contaminants are filtered from the exhaust and, in some situations, burned off further. Non-particulate contaminants are converted to non-pollutants. Both types of pollutants can also be generated from non-engine sources such as “off-gas” chemical reactions and evaporative emissions.

Air pollution can cause serious health problems for humans and the environment. Ground level ozone and airborne particles are two pollutants that have one of the greatest threats to human health in the United States. Ozone (O ₃ ) can irritate the respiratory system and cause coughing, throat irritation, and / or burning sensation of the respiratory tract. Ozone is involved in the formation of smog. Ozone can also reduce asthma by reducing lung function, causing chest tightness, wheezing and shortness of breath. Particle contamination consists of droplets of microscopic solids or liquids that are small enough to penetrate deep into the lungs and cause serious health problems. When exposed to these small particles, people can experience nasal and throat irritation, lung injury and bronchitis, which can increase their risk of heart or lung disease. The short-term effects of air pollution include irritation to the eyes, nose and throat. Upper respiratory tract infections such as bronchitis and pneumonia can also occur. Other symptoms include headache, nausea and allergic reactions. Long-term health effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver or kidney. Repeated exposure to air pollution affects the lungs of growing children and can exacerbate or complicate medical symptoms in the elderly.

  Medical symptoms resulting from air pollution can be costly. Health care costs, productivity loss in the workplace, and the impact on human welfare result in billions of losses each year. Understanding the health effects of pollution and finding a means to improve, prevent, or eliminate pollution not only enhances the overall respiratory health of the population, but also supports the health management system. Cost and cost will also be reduced.

  For all of these reasons, governments, environmental agencies and various manufacturing industries have pledged to reduce the level of air pollution emitted from various sources. Government agencies are the main bodies that set emission standards and implement regulations. In the European Union (EU), regulations come from the legislation of the European Community, with individual countries implementing the regulations. For example, many EU states have taxed sources that cause excessive air pollution. A recent achievement was the Kyoto Protocol, which ordered a global reduction of greenhouse gases. Many countries, including the EU, have ratified the Protocol. The EU, Japan and the United States set some of the strictest standards in the world, but many other countries, such as Argentina, Brazil, Mexico, Korea, Thailand, India, Singapore and Australia, all have regulations on air pollution. Established. In the United States, there are many different groups that affect regulations in certain areas: state environmental agencies (eg, California Air Resources Board (CARB)), national parks, forest departments, and mines safety and health agencies. Some states and metropolitan areas that failed to meet the National Environmental Air Quality Standard (NAAQS) have been pointed out as “non-achieved areas” and have implemented their own standards. CARB has historically been one of the strictest government agencies regulating air pollution in the United States. However, the first US regulatory agency is the Environmental Protection Agency (EPA). It was created by the Nixon administration in a 1970 amendment to the Clean Air Act (CAA) of 1963. The Clean Air Act is a comprehensive federal law that regulates atmospheric emissions from regions, fixed sources and mobile sources (see, for example, 42 USC SS7401 and below (1970) of the Clean Air Act). The Clean Air Act has five major amendments, the latest of which is 1990. The 1990 amendments to the Clean Air Act will largely address issues that have not been considered or have been fully considered, such as acid rain, surface-level ozone, stratospheric ozone depletion, and air toxic substances. intended. These amendments called for the EPA to issue 175 new regulations, including automobile emissions, gasoline reform, the use of ozone-depleting chemicals, and more.

In accordance with the Clean Air Act enactment, the EPA has established regulations for pollutants that can or may harm people. The definition of “reference pollutant” includes (1) ozone (O ₃ ), (2) lead (Pb), (3) nitrogen dioxide (NO ₂ ), (4) carbon monoxide (CO), (5 ) Particulate matter (PM), and (6) sulfur dioxide (SO ₂ ). Each reference pollutant is listed in turn.

Ground level ozone (a major component of smog) remains an environmental pollution problem in the United States. Ozone is not directly discharged to the atmosphere, in the presence of heat and sunlight, is produced by the reaction of volatile organic compounds (VOC) or a reactive organic gases (ROG) and nitrogen oxide (NO _X). VOC / ROG is emitted from a variety of sources such as combustion fuels and from solvents, petroleum refining and pesticides, which are sources such as automobiles, chemical factories, refineries, manufactories, consumers and commercial products. , As well as from other industrial sources. Nitric oxide is emitted from automobiles, power plants, and other combustion sources. Ozone and precursor pollutants that produce ozone can be carried miles from their original source by the wind. In 1997, the EPA revised the national environmental air quality standards for ozone by replacing the 0.12 part per million (ppm) standard with the new 8-hour 0.08 ppm standard.

Nitrogen dioxide (NO ₂ ) is a reactive gas that can be generated by the oxidation of nitric oxide (NO). Nitrogen oxide (NO _x ), the term used to describe NO, NO ₂ , and other nitrogen oxides, plays a major role in the generation of ozone and smog. As a major cause of discharge of artificial NO _X, automobiles, construction equipment, and include a high temperature combustion processes such as occur in power plants. Household heater and gas stove, to generate a large amount of NO _2.

  Carbon monoxide (CO) is a colorless, odorless, and harmful gas that can be generated by incomplete combustion of carbon in fuels. Automotive emissions account for about 60% of CO emissions in the United States. In urban areas, it is said that about 95% of CO emissions come from automobile exhaust. Other causes of CO emissions include natural processes such as industrial processes, non-transport fuel combustion, and forest fires.

Particulate matter (PM) is a term used for a mixture of solid particles and liquid droplets found in the atmosphere. Some particles are large enough or dark to be observed as soot or smoke. Others are so small that they can only be detected with an electron microscope. These particles that occur in a wide range of sizes (“fine” particles are less than 2.5 μm in diameter and coarser particles are greater than 2.5 μm) can be found in many different fixed and mobile sources, as well as natural Derived from the source. Fine particles (PM-2.5) result from fuel combustion from automobiles, power generation and industrial facilities, and from residential fireplaces and wood stoves. Coarse particles (PM-10) are generally emitted from vehicles traveling on unpaved roads, material handling equipment, and sources such as crushing and grinding operations and dust. Some particles are emitted directly from their sources, such as chimneys and automobiles. In other cases, gases such as sulfur monoxide, SO ₂ , NO _x and VOC interact with other compounds in the atmosphere to form fine particles. Their chemical and physical composition varies with location, season and weather. 1997, EPA is added two new PM-2.5 standards, with respect to the year and 24 hours reference was set to 15μg / ^{m 3} (μGA) and 65 [mu] g / ^{m 3,} respectively.

  Sulfur dioxide can be produced, for example, during metal refining and other industrial processes when sulfur-containing fuels (eg, coal and oil) are combusted.

  The last reference pollutant, lead, has historically resulted from the use of leaded fuel in automobiles. As a result of regulatory efforts to reduce the content of Pb in gasoline, involvement from the transportation sector has decreased over the past decade. Today, metalworking is a major source of Pb emissions into the atmosphere.

  The Clean Air Act is indispensable for EPA, and is written to develop a plan to meet the national environmental air quality standards for these six reference pollutants. In addition to the six, there is a separate list of 188 “toxic air pollutants”. Examples of toxic air pollutants include benzene (found in gasoline); perchlorethylene (exhausted from some dry cleaning facilities); and methylene chloride (used by many industries as a solvent and paint stripper) ). Some atmospheric toxic substances are emitted from natural sources, but most include both mobile sources (eg passenger cars, trucks and buses) and stationary sources (eg factories, refineries and power plants) Arising from the source of the cause. The CAA asked EPA to provide a two-step program for these 188 contaminants. The first stage consists of identifying sources of toxic contaminants and developing technology-based standards to significantly reduce them. EPA has established a list of over 900 fixed sources, which allows many industrial sources such as chemical factories, refineries, aerospace manufacturers and steel mills, and smaller sources such as dry cleaners, Created new atmospheric toxic emission standards affecting sterilizers, lead smelters and chromium electroplating facilities. The second stage consists of strategies and programs that assess residual risk and ensure that the overall program has achieved substantial reductions; this stage is still ongoing.

  Internal combustion engines are directly affected by the above regulations because they emit standard pollutants. These engines operate on two fuels. The most common types of fuel used are gasoline and diesel. Each type of fuel contains a complex mixture of hydrocarbon compounds as well as trace amounts of many other substances such as sulfur. Even when completely burned, these fuels produce pollutants. In addition, because the engine cannot “completely” burn, some fuels are incompletely oxidized, thus creating additional pollutants. Other types of fuels may also be used, such as ethanol mixtures, vegetable oils, and other fuels known in the art.

  In gasoline engines, in order to reduce emissions, modern car engines carefully control the amount of fuel they burn. They try to maintain the air to fuel ratio very close to the stoichiometric point, which is the calculated ideal ratio of air to fuel. Theoretically, at this ratio, all the fuel is burned using all of the oxygen in the air. The fuel mixture actually varies considerably from the ideal ratio during operation. Sometimes the mixture can be low quality (eg, an air to fuel ratio higher than a typical ratio of 14.7), and in other cases the mixture can be rich (eg an air to fuel ratio lower than 14.7). . Because of these deviations, various atmospheric emissions occur.

Many emissions from car gasoline engines include nitrogen gas (N ₂ ) (78% of the atmosphere is N ₂ ), carbon dioxide (CO ₂ ) as a combustion product, and water vapor (H ₂ O). These exhausts are almost harmless to humans (although excessive levels of CO ₂ in the atmosphere are believed to be responsible for global warming). However, gas warp engine are carbon monoxide, nitrogen oxides, and incombustible formed hydrocarbons (all of which are included in the reference pollutants EPA) also generates (noncombustible formed hydrocarbons, ozone forming mechanism with NO _X Part of).

Diesel engines are also involved in reference pollutants. These engines use a hydrocarbon fraction that self-ignites when fully compressed in the presence of oxygen. In general, diesel burning in a cylinder produces more particulate matter and pollutants nitrogen oxides and sulfur oxides (NO _x and SO _x, respectively) than in gasoline. Nevertheless, diesel mixtures are generally low quality and there is a relatively large amount of oxygen. As a result, the combustion of small molecule hydrocarbons is usually more complete and produces less carbon monoxide than gasoline. Longer chain hydrocarbons are more difficult to burn completely and can result in the formation of particulate residues such as carbon “soot”.

  Despite these drawbacks, fossil fuels are relatively abundant, easy to handle, and economical. Therefore, these fuels will continue to be representative of significant sources of mechanical power and contamination over the next few years. Furthermore, the dissemination of internal combustion engines indicates how fossil fuels continue to be a necessary source of energy.

  There are at least three markets for internal combustion engines that produce significant air pollution: 1) mobile on-road engines, equipment and vehicles, 2) mobile non-road engines, equipment and vehicles, and 3) fixed or “point” sources. In each of these markets, government agencies and other organizations directed restrictions on the level of air pollution. These limits have become increasingly severe as the number of internal combustion engines in use increases and, in addition, when examining the harm caused by air pollution. Constantly strict regulations have required the industry to continuously research, develop and operate on new emission control technologies, from fuel formulations for engine design changes to aftertreatment devices. These technologies change both effectiveness and cost, but have become essential for companies to comply with regulations. Since a single emission control technology could not remove all relevant pollutants, many technologies are often used together to ensure that certain types of vehicles or equipment meet regulatory emission limits. Must be done. These markets, their regulations and the technology on which they are based are described in the following paragraphs. Techniques including their advantages and disadvantages are described in more detail after this section. While this section focuses on US engines, equipment and vehicles, other areas have similar products and regulations. For example, the EU has a similar market size but is selective over exhaust gas recirculation because diesel emission control technology uses catalytic converters for most small off-road engines, and most vehicles have diesel engines. Focuses on catalytic reduction. Other areas have their own qualities that differ from the United States, but essentially use similar types of equipment and limit similar types of air pollutants.

  Mobile on-road engines, equipment and vehicles include passenger cars, cargo trucks, minivans, sports vehicles (SUVs), buses, luggage delivery trucks, semi trucks, passenger vans, and 2 or 3 designed for on-road use Examples include, but are not limited to, wheeled motorcycles. These markets have historically set examples for emission control and continue to do so today in accordance with regulations that support low levels of air pollution.

  The passenger car and truck market is divided by weight. Those with a gross vehicle weight (GVWR) of 3,856 kg (8,500 pounds) or less are considered small cars. A 3,856-4,536 kg (8,500-10,000 lbs) GVWR vehicle designed for passenger transport is considered a medium-sized vehicle. Vehicles over 3,856 kg (8,500 lbs) GVWR that are not designed for personal use are referred to as large vehicles.

  Conventionally, passenger cars and small cars have been regulated by vehicle weight and fuel type, but will be regulated by one group in future standards. Less than 1% of the approximately 17 million new passenger cars and small vehicles manufactured in the US use diesel engines. Passenger cars and small vehicles include Ford, General Motors (GM), Daimler Chrysler, BMW, Honda Motor (Honda), Hyundai, Daewoo, First Automobile Group, Toyota, Nissan, SAIC-Chevy And Fuji Heavy Industries (Subaru).

Regulations on passenger cars and small vehicles have existed for decades, but in recent years they have become more stringent. Tier 2 standards, phased in from year (MY) 2004-2009, to guarantee their fleet to certain “big box” standards and to maintain a corporate average for NO _x emissions Requires original equipment manufacturer (OEM). Vehicles under 2,722 kg (6,000 lbs) GVWR must be fully followed by 2007, 2,722-3,856 kg (6,000-8,500 lbs) and MDV up to 2009 Must follow. Contaminants included in the standards include: NO _x , formaldehyde (HCHO), CO, PM and non-methane organic gases. California has historically been more stringent than EPA, but other states, such as New Jersey, New York, Vermont, Maine, and Massachusetts, have joined California's lower emission levels for new and used cars. . Manufacturers that do not meet the standards are essentially banned from making their vehicles in these markets and fined for those found in the market. In the after-service market, the state regulates emissions of cars and small vehicles through an inspection and maintenance (I / M) program. These programs are often created from State Implementation Plans (SIPs) required in areas that do not meet National Environmental Air Quality (NAAQ) standards. Meeting both new vehicle standards and after-service market standards often requires the use of emission control technology in equilibrium.

  Historically, three-way catalytic converters have had widespread use in passenger cars and small vehicles. Recent improvements in these converters (eg, increased substrate porosity, washcoat optimization, reduced catalyst loading, etc.) have resulted in incremental improvements in emissions control. In order to meet the latest set of US regulations, manufacturers will probably increase the amount of catalyst added or the number of substrates per vehicle. Cars in use that do not meet inspection / maintenance standards must replace defective technology or purchase additional equipment. Other emission control devices include improved injection systems (eg injection timing, injection pressure, rate shaping, common rail injection and electronic control), combustion chamber design changes (eg higher compression ratio, piston shape and fuel injector position), Examples include, but are not limited to, variable valve timing, catalytic converters and filters.

  Heavy vehicles (HDV) include both personal and commercial trucks and buses that exceed 3,856 kg (8,500 lbs) GVWR. The majority of these engines run on diesel fuel; in the United States, more than 300,000 are produced each year. Manufacturers and engine suppliers include, but are not limited to, Cummins, Caterpillar, Detroit Diesel, GM, Mack / Volvo, International / Navistar, Sterling, Western Star, Kenworth and Peterbit. Other companies that provide other emission control technologies for the after-sales market include, but are not limited to, Donaldson, Engelhard, Johnson Matthey, Lubrizol, Fleetguard, Cleaire, Clean Air Partners, and Engine Control Systems.

Heavy trucks face strict emission reduction standards for PM, NO _x , CO and non-methane hydrocarbons (NMHC). PM standards will be implemented in 2007, while NO _x and NMHC standards will be introduced in stages from 2007-2010. Like small vehicles, California, along with certain other states and metropolitan areas, often established emission standards that were more stringent than EPA. For vehicles that do not meet the criteria, manufacturers are prohibited from selling them. Penalties for NO _x range up to $ 12,000 per vehicle based on size and compliance efforts. Other industries, such as locomotives, fisheries, agriculture and construction, use engines very similar to those for heavy vehicles, but the HDV market faces the most stringent emission standards. On the other hand, some states and metropolitan areas (eg California, New York City, and Seattle) require further equipment improvements or offer rewards for equipment improvements to further lower pollutant levels. These regions have certified technologies that meet the authorization level and requirements. Examples include Donaldson's diesel oxidation catalyst muffler and diesel particle filter, Cleaire's diesel oxidation catalyst and diesel particle filter, and Johnson Matthey's continuous regeneration technology particle filter.

Emission control technologies used to meet these standards and to improve equipment include improved injection systems (injection timing, injection pressure, rate shaping, common rail injection, electronic control), exhaust gas recirculation, and combustion chamber Engineering change (higher compression ratios, piston geometry, and injector location), improved turbocharging, ACERT, diesel particulate filters, NO _x adsorbent, selective catalytic reduction, conventional catalytic converters, catalytic exhaust mufflers, and diesel oxidation catalyst However, it is not limited to these. Meeting the 2007 standards has sparked new research and development on many of these emission control technologies. Huge costs and efforts have been introduced to determine the 2007 HDV emission control solution.

Motorcycles are another type of mobile, on-road vehicle, examples include both two- and three-wheel motorcycles designed for on-road use. Motorcycles mainly use gasoline fuel. Manufacturers include, but are not limited to, Harley Davidson, BMW, Honda, Kawasaki Heavy Industries (Kawasaki), Triumph, Tianjin Gangtian, Lifan Motorcycle, and Yamaha. Regulations on on-road motorcycles were adopted in 1978 and remained unrevised during 2003 until new standards in accordance with California regulations were agreed. Contaminants monitored by the new standards include HC, NO _x and CO.

  Emission control technology for motorcycles includes conversion of 2-stroke engine to 4-stroke engine, improved injection system (injection timing, injection pressure, rate shaping, common rail injection and electronic control), pulse air system, combustion chamber design change ( Higher compression ratio, piston shape and fuel injector position), and use of a catalytic converter, but are not limited to these. Limitations in motorcycle emission control technology differ from those of small or large vehicles. Because there is little place to “hide” the equipment and passengers are very close to the exothermic oxidation reaction, motorcycles are more focused on the overview, configuration, and heat of the aftertreatment equipment.

  Mobile, non-road engines, equipment and vehicle categories include engines for agriculture, construction, mining, turf and garden, personal ships, ships, commercial ships, locomotives, aircraft, snowmobiles, off-road motorcycles and ATVs. However, it is not limited to these.

  Small engines emit significant levels of air pollution for their size; they are the largest contributor to non-road HC residues. Small engine equipment includes, but is not limited to, leaf blowers, trimmers, brush cutters, chainsaws, lawn mowers, engine mowing carts (riding mowers), wood splitters, snow plows and chippers. Engine and equipment manufacturers include John Deere, Komatsu, Honda Motor Co., Ltd. (Honda), Ryobi, Electrolux (Husqvaruo and Poulan; also supplied by Craftsman), Fuji, Tecumseh, Stihl, American Yard Products, and Briggs and Stratton. However, it is not limited to these.

  EPA began regulating small engines in 1993 (stage I), the standards came into effect in 1997, and continued to reduce emissions levels with new standards in 2002 (stage II). These standards divide equipment into hand-held and non-hand-held categories and classify based on different engine displacements. These regulations focus on hydrocarbon and nitric oxide emissions.

  Emission control technologies include the use of catalysts (ie John Deere's LE technology and Komatsu's “stratified scavenging” design), conversion of 2-stroke engines to 4-stroke engines, improved injection systems (injection timing, injection pressure) , Rate shaping, common rail injection and electronic control), or combustion chamber design changes (higher compression ratio, piston shape and fuel injector position).

  The recreational vehicle market includes off-highway motorcycles, snowmobiles and rough terrain vehicles (ATVs). These are manufactured by manufacturers and engine suppliers, examples of which are given below:

  Honda Motor Co., Ltd. (Honda), John Deere, Kawasaki Heavy Industries (Kawasaki), Mitsubishi Motors (Mitsubishi Motors), Nissan Motor (Nissan), Toyota Motor Corporation (Yanmar), Arctic Cat, Bombardier, Brunswisk, International Powercraft, Polaris, Suzuki, and Yamaha.

EPA began to regulate recreational vehicles later than many other markets, but California had regulations in place in advance. EPA has a phased introduction from 2006-2009 for snowmobiles and from 2006-2007 for off-highway motorcycles and ATVs. The regulated pollutants, HC, CO and NO _x and the like. Emission control technology for recreational vehicles includes conversion of 2-stroke engines to 4-stroke engines, improved injection systems (injection timing, injection pressure, rate shaping, common rail injection and electronic control), pulse air or combustion chamber design changes ( Higher compression ratio, piston shape and fuel injector position), but are not limited to these.

  For mining, regulations are established by the Mine Safety and Health Agency. Due to the high levels of vibration, shock and dust, mining is often considered one of the most troublesome environments for equipment. Temperature and flammability are also major issues in mining. Diesel oxidation catalysts have been improved for some mining equipment, but diesel particle filters are becoming more common.

  In the agricultural and construction markets, EPA regulates both spark ignition and compression ignition engines. These can be used for tractors, forklifts, bulldozers, generators, paving machines, rollers, trenchers, excavators, mixers, cranes, balers, compressors and the like. Engine and equipment manufacturers include, but are not limited to, Agco, Komatsu, CNH Global, Caterpillar, Cummins, Daewoo, John Deere & Co, Dueutz, Detroit Diesel, and Kubota.

  EPA began regulating the diesel portion of these engines in 1994 (Tier 1), and more recently, increased standards in Tier 2 (performed from 2001-2006). The standard is scheduled to grow again at the Tier 3 level in 2006-2008. The Tier 3 level may require the use of emission control devices similar to those used for heavy vehicles (eg, tractor trailers). Gasoline, liquid propane gas, or compressed natural gas (CNG) engines used for agricultural and construction applications have also recently changed in regulation. Tier 1 levels begin in 2004 and are comparable to those adopted earlier by CARB; Tier 2 levels are expected to start in 2007. There is a voluntary program for vehicles that show lower emissions than the standard and is called the “Blue Sky Series”. Based on engine size and fuel type, the levels of particles, carbon monoxide, nitric oxide and non-methane hydrocarbons are all significantly different for routine phased introduction and for upcoming standards. Must be reduced.

Emission control technology is similar to that used in large vehicles, examples include improved injection systems (injection timing, injection pressure, rate shaping, common rail injection and electronic control), exhaust gas recirculation, combustion chamber design changes ( higher compression ratios, piston geometry, and injector location), improved turbocharging, ACERT, diesel particulate filters, NO _x adsorbers, selective catalytic reduction, conventional catalytic converters, catalytic exhaust mufflers, and diesel oxidation catalyst For example, but not limited to. Exhaust gas recirculation (EGR) has been problematic because of the tendency to produce sulfuric acid during engine suction. It also requires cooling, which requires a larger radiator and therefore entails a larger head on the vehicle, creating aerodynamic and fuel economy constraints.

  In marine applications, engines can generally be categorized by use of gasoline or diesel fuel, personal use or commercial use, or by engine size. Marine units range from personal water bikes to yachts, ferry ships, dredgers and ocean-going vessels. Manufacturers and engine suppliers include Bombardier (Evinrude, Johnson, Ski Doo, Rotax, etc.), Caterpillar, Cummins, Detroit Diesel, GM, Isuzu, Yanmer, Alaska Diesel, Daytona Marine, Marine Power, Atlantic Marine, Bender Shipbuilding, Bollinger Shipyards, VT Halter Marine, Eastern Shipbuilding, Gladding-Hearn, JeffBoat, Main Iron Works, Master Boat, Patti Shipyard, Quality shipyards, and Verret Shipyard, MAN B & W Diesel, Wartsila, Mitsubishi Motors (Mitsubishi) , Bath Iron Works, Electric Boat, Northrop Grumman (including but not limited to Avondale, Ingalls, and Newport News Shipyards).

EPA regulates ships, whether recreational, personal or commercial. The main categories are based on engine displacement from recreational vehicles to tankers. Diesel marine non-recreational ships with a displacement of 30 liters (30L) or less, such as fishing boats, tugboats, tugboats, tugboats and cargo ships, are new to NO _x and PM that will be enforced between 2004 and 2007, depending on engine size. Have standards. Diesel marine non-recreational vessels of more than 30L, for example, container ships, tankers, bulk carriers and cruise ships, is enforced NO _x standard (Tier1) in 2004, in 2007 further HC, standards of PM and CO (Tier2 ) Is enforced. Diesel marine recreational vessels, such as yachts, cruisers and other types of recreational vessels, have standards comparable to those of diesel marine non-recreational vessels with a displacement of 30L or less, but are based on engine sizes in 2006-2009. Have a later run date in the range. Gasoline and diesel ships only have regulations that generally apply HC emissions in outboard engines, personal ships and jet boats. Sterndrives and inboard engines are inherently clean and not yet regulated.

  Emission control technology is similar to that used for large vehicles, examples include the use of a “green terminal” when the ship is in the dock, conversion of a 2-stroke engine to a 4-stroke engine, cooling after water, Exhaust gas recirculation, diesel particulate filter, selective catalytic reduction, diesel oxidation catalyst, catalytic converter, improved fuel injection system (injection timing, injection pressure, rate shaping, common rail injection and electronic control), improved turbocharging, variable Examples include, but are not limited to, valve timing, and combustion chamber design changes (higher compression ratio, piston shape and fuel injector position). The use of a small engine for auxiliary power (eg, auxiliary power unit, APU) also helps control emissions. Although salt water and its associated pollutants and cooling effects on ships are difficult to post-process, APU can work well with post-processing equipment.

  The locomotive industry relies primarily on diesel fuel (with limited use of coal and firewood), freight and passenger rail services, long-distance transportation services, regular train services, and switch yard services. Including trains used in In the United States, more than 600 trains are produced every year. Manufacturers and engine suppliers include, but are not limited to, GM's Electromotive Division, GE Transportation Systems, Caterpillar, Detroit Diesel, Cummins, MotovePower, Peoria Locomotive Works, Republic Locomotives, Trinity, Greenbrier, and CSX.

Train regulation began in 2000 and was widely modeled on heavy vehicles. The standards include the level of newly manufactured engines as well as remanufactured engines (performed about every 4-8 years) and will vary depending on whether the engine is for switching or long-distance transportation. Tier 0 is applied to engines of year (MY) 1973-2001, Tier 1 is applied to engines MY 2002-2004, and Tier 2 is applied to engines MY 2005 and later. Penalties can range up to $ 25,000 per engine per day. The contaminants are regulated, it contains opacity by particulate matter, NO X, _HC, CO, and smoke.

Emission control technology is similar to that used for large vehicles, examples include improved fuel injection systems (injection timing, injection pressure, rate shaping, common rail injection and electronic control), exhaust gas recirculation, combustion chamber design changes (higher compression ratios, piston geometry, and injector location), selective catalytic reduction, diesel oxidation catalysts and aftercooler, split cooling, including but zeolite sieves and nO _x reduction catalyst, and the like. Throughout the use of small auxiliary power devices, such as aftertreatment devices, the use of those that exhibit fewer limitations is also becoming an emission control strategy.

The aircraft market includes all types of aircraft, such as those manufactured by Boeing, Airbus, Cessna, Gulfstream and Lockheed Martin. Both the EPA and the European Union follow the International Civil Aviation Organization (ICAO) emission standards. EPA adopts the latest standards of ICAO regarding CO and NO _x in the gas turbine during engine in 1997, was adopted their HC levels in 1984. In the United States, the FAA monitors and enforces these standards. Much of emission control is performed by engine technology and fuel changes.

Fixed sources include non-movable sources of contaminants. EPA has over 80 categories of major industrial sources (eg, power plants, chemical plants, oil refineries, aerospace and steelworks) and smaller categories of sources (eg, dry cleaners, commercial sterilizers). , Secondary lead smelters and chromium electroplating facilities). The power plant can utilize stationary diesel engines, stationary gas turbines and nuclear power, among other sources of pollution. Each of these sources produces different pollutants (eg, nuclear power plants produce iodine and hydrogen, gas turbines produce NOx, CO, SOx, CH ₄ and VOCs, refineries produce gas steam, CO2 , NOx, VOCs, CO ₂ , CH ₄ and PM). Each industry requires different control technologies to reduce atmospheric emissions.

The EPA regulations cover six reference pollutants and an additional 188 toxic air pollutants. Specific programs executed, Acid Rain Program (intended to reduce the sulfur emission), and NO _x allocation plan of the ozone mobile Committee (intended to reduce NO _x emissions) is Can be mentioned. RECLAIM is an established plan for buying and selling NO _x and SO _x credits. In addition, capping and trading plans have been implemented in several industries and territories, allowing companies to buy and sell their emission credits.

  The techniques used to control emissions from fixed sources vary widely, including filters, washers, adsorbents, selective catalytic reduction (SCR), dust collectors, zero-slip catalysts, Examples include a turbine catalyst or an oxidation catalyst. Some exhaust control system suppliers to the fixed pollution market include M + W Zander, Crystall, Jacobs E. , Takasogo, IDC, ADP, Marshall, Bechtel, Megte, Angui, Adwest, Eisenmann, Catalytic Products, LTG, Durr, Siemens, Alston. Catalyst suppliers include Nikki, BASF, Cormetech, WR Grace, Johnson Matthey, UOP, and Sud Chemie.

Because of the importance of improving air quality and complying with relevant laws and regulations, considerable time, money and effort has been put into technologies that can reduce emissions. Three general areas of technology are listed below: a) engine improvements; b) fuel improvements; and c) aftertreatment. These approaches are typically not mutually exclusive or stand-alone solutions. Engine improvements include, but are not limited to, technologies such as improved injection systems, exhaust gas recirculation, electronic sensors and fuel control, combustion chamber design, improved turbocharging, and variable valve timing. Fuel improvements include formulations such as high cetane, low aromatics, low sulfur fuels, fuel addition catalysts, liquefied petroleum gas (LPG), fuel oxygenation, compressed natural gas (CNG) and biodiesel. However, it is not limited to these. Post-processing techniques include, but are not limited to, catalytic converters (2, 3, and 4-way), particle traps, selective catalytic reduction, NO _x adsorbers, HC adsorbers, NO _x reduction catalysts, and the like. Some systems include various parts of these and other technologies: ACERT from Caterpillar, or catalyzed diesel particle traps are examples of combination systems and equipment. There are also several technologies whose use is currently limited due to technical or commercial limitations.

  Improved injection systems include injection timing, injection pressure, rate shaping, air-assisted fuel injection, sequential multipoint injection, common rail injection, injector hole resizing and movement, and some electronic control changes. In the common rail system, the microcomputer-treated fuel pump controls the flow rate and timing of the fuel (eg, Mercedes-Benz E320 uses this system). Secondary air injection can promote HC and CO combustion in the manifold. Changing the injection system can reduce various emissions and improve fuel economy; however, this requires significant work on the engine to ensure efficiency.

Exhaust gas recirculation (EGR) returns some exhaust gas to the intake of the engine. By mixing the exhaust gas with fresh intake air, the amount of oxygen entering the engine is reduced, resulting in lower nitric oxide emissions. EGR does not require regular maintenance and works well in combination with high rotation, high turbulent combustion chambers. EGR is low fuel efficiency and engine life, has greater demands vehicle cooling system, limited to the action not being及contaminants other than NO _x, and control algorithms and require a sensor, also has disadvantages such as . For these reasons, EGR is often used in parallel with other control techniques. Companies involved in EGR technology include Doubletree Technologies, ETC, STT Emtec, Cummins, Detroit Diesel, Mack and Volvo.

  Optimizing the combustion chamber, or making incremental improvements to it, is another way that manufacturers and developers control emissions. Gap volume reduction limits the trapping of non-combustion fuel (and thus HC formation), while reducing the amount of lubricating oil can also reduce HC formation and limit catalyst poisoning. Other means include: improved cylinder and piston surface finishes, improved piston ring design and materials, and improved exhaust valve system seals. Furthermore, “rapid burning” combustion chambers are manufactured by increasing the combustion rate, reducing the ignition advance, adding a diluent to the air / fuel mixture, and / or increasing the turbulence in the chamber. obtain. Combustion chamber optimization can result in reduced emissions, which is another technique that requires engine rework, which can be an expensive process.

  Variable valve timing includes adjusting the engine valve to open and close to maximize fuel and engine efficiency. Sensors are often used to detect engine speed and adjust the valves to open and close accordingly. This technique can increase engine torque and horsepower, improve rotation and intake charge speed, and thus improve combustion efficiency. Variable valve technology does not reduce emissions by the same amount as some other technologies, and often results in reduced fuel efficiency.

Some fuels naturally pollute efficiency more than others, while others tend to poison the catalyst that should clean the exhaust, so re-prescription or the use of a different fuel is another emission control. Technology. For example, the transition from leaded fuel to unleaded fuel in the United States has greatly reduced lead emissions. By lowering the sulfur content in the fuel, reducing SO _x emissions, and because sulfur may poison the catalyst, increasing the efficiency of many catalytic converters. Natural gas is another type of fuel typically produce fewer particulate contamination diesel fuel, and can also reduce NO _x and combustion noise. Conversely, natural gas can increase vehicle weight (because it requires a high pressure tank) and has refueling limitations.

  The use of aftertreatment devices (equipment used after the fuel is burned) is very common in certain industries that are affected by emission control regulations. An example of an aftertreatment device is a catalytic converter. Although catalytic converters can vary widely and have different functions, a general description is an apparatus that treats exhaust by the use of a catalyst. The composition of the substrate and the catalyst present thereon has changed over the years, as well as the configuration and number of converters.

_Two -way catalytic converters perform oxidation of gas phase contamination, such as oxidation of HC and CO to CO ₂ and H ₂ O. Diesel oxidation catalyst (DOC) is another type of 2-way catalytic converter used with diesel engines. These converters are effective in the control of HC and CO, but most requiring maintenance, they are obtained by increasing NO _x emissions, it is sensitive to sulfur.

A 3-way catalytic converter performs both oxidation (conversion of CO and HC to CO ₂ and H ₂ O) and reduction (conversion of NO _x to N ₂ gas) reactions. Since the 1970s, 3-way catalytic converters have reduced vehicle emissions. Further performance improvements with these devices are limited by a number of factors, such as the temperature range and surface area of their substrates, and by catalyst poisoning. Some vehicles require many catalytic converters to meet increasingly stringent regulations.

  The 4-way catalytic converter performs oxidation and reduction reactions, traps particles and burns them out (regeneration can occur in an active or passive manner).

  Suppliers of catalytic converters and their related parts include Corning, NGK, Denso, Ibiden, Emitec, Johnson Matthey, Engelhard, Catalytic Solutions, Delphi, Umcore, 3M, Hemicore ), Hermann J. et al. Schulte (HJS), Clean Diesel Technology, Cleare, Clean Air Systems, ArvinMeritor, Tenneco, Eberspacher, Faurecia, Donaldson, and Fleetguard.

  Because diesel fuel produces more particulate matter than gasoline or some alternative fuel, particle traps or filters are another type of aftertreatment device commonly used in diesel applications. In a diesel particle trap (DPT), particles in the exhaust stream pass through a filter that collects them. Removal of particulate matter collected on the trap is called “regeneration” and can occur in many ways. One method uses an external heater to raise the temperature of the filter to the level necessary for PM to “burn out”. Another method releases a small amount of diesel fuel in the exhaust stream. When fuel particles come into contact with the filter, the fuel burns out at high temperatures. This high temperature also burns PM from the filter. Yet another means is to use a fuel addition catalyst to promote regeneration. In another approach, referred to as “catalyzed diesel particle trap”, the catalyst is applied directly to the filter itself, which lowers the temperature required to burn out PM. Finally, an oxidation catalyst can be used on the front surface of the filter to promote PM burnout. Johnson Matthey's continuous regeneration trap (CRT) is such a system. Diesel particle traps can reduce PM by as much as 85% in some applications. Traps that utilize a catalyst can reduce other contaminants (eg, HC, CO, and PM) in addition to PM by using the catalyst (as described above). Conversely, these traps become clogged with PM, soot and ash and the catalytic treatment version can be toxic. They also add cost and weight to the vehicle.

  Diesel particle traps come in many different types of filters, such as ceramic monolithic cell filters (Corning, NGK), fiber wind filters (3M), knitted fibers (BUCK), woven fibers (HUG, 3M), sintered metal fibers (SHW, HJS), filter paper or the like may be used. Suppliers of these devices and their related technologies include, but are not limited to, Donaldson, Engelhard, Johnson Matthey, HJS, Eminos, Deutz, Corning, ETG, Paas, and Engine Control Systems.

Selective catalytic reduction (SCR) is another example of an aftertreatment system. In this technique, a chemical that can act as a reducing agent, such as urea, is added before the exhaust reaches the catalyst chamber. Urea hydrolyzes to produce ammonia. Ammonia then reacts with the exhaust gas NO _x to produce N ₂ gas, thereby reducing NO _x emissions. Ammonia can be injected directly or retained in the form of solid urea, urea solution, or in crystalline form. Oxidation catalysts are often used in parallel with the SCR to reduce CO and HC. Unfortunately, SCR is effective in reducing NO _x, but and shows a low catalytic degradation with good fuel economy, SCR requires a substructure for refilling the additional tank and the tank on the vehicle. It also depends on end user compliance; in order to maintain emission control, companies and operators are required to refill the tank. Suppliers of SCR or components thereof include, but are not limited to, Engelhard, Johnson Matthey, Miratech Corporation, McDermott, ICT, Sud Chemie, SK Catalysts, and PE Systems. Although only limitedly used in the United States, SCR is expected to be widely used in Europe to reduce emissions, especially in the heavy truck market.

NO _x adsorbents are substances that store NO _x under low quality conditions, release it under fuel rich conditions (typically every few minutes), and catalytically reduce it. While this technology can work in both gas and diesel applications, gas provides a better fuel rich, high temperature environment. NO _x adsorbents reduce the levels of HC, NO _x and CO, but have little or no effect on PM. NO _x adsorbents can function over a wide range of temperatures. Conversely, NO _x adsorption capacity decreases based on temperature, requires engine control and sensors, and is functionally hindered or disabled by the sulfur content in the fuel. In diesel applications, there are additional constraints including the amount of oxygen present in the exhaust, HC utilization, temperature range and smoke or particle production.

The NO _x reduction catalyst can be implemented to 1) actively inject a reducing agent into the system before the catalyst; and / or 2) use a washcoat with zeolite adsorbing HC and thus reduce NO _x. It can also be used to control exhaust by creating an oxidized region. This technique is capable of reducing NO _x and PM, it is costly than many other techniques, may result in lower fuel consumption or sulfate particles.

  HC adsorbents are designed to trap VOCs while the catalyst is cold and then release them when the catalyst is heated. This is: 1) coating the adsorbent directly on the catalytic converter substrate, which is minimal change but allows low control, 2) separate but connected and converters in front of the catalytic converter It can be carried out by placing the adsorbent in an exhaust pipe with an air switching groove that acts once heated and / or by configuring the adsorbent after the catalyst. The last two options require a cleaning option for the adsorbent. This technique reduces cold starting exhaust, but is difficult to control and requires additional costs.

Emission control technologies are often combined in a system because emissions have proven difficult to control. Examples of combination systems include: DeNO _x and DPT (eg, HJS SCRT system), catalytic converter configured in the muffler, SCR integrated with the muffler, or catalytically treated diesel particulate filter.

  ACERT is another example of a system that incorporates multiple emission control technology. ACERT (from Caterpillar) targets four areas: intake air handling, combustion, electronics, and exhaust aftertreatment. Important components include single and series turbocharging to cool intake air; variable valve actuation to improve fuel combustion; electronic manifold to integrate computer control; and rear exhaust Catalytic conversion to reduce the particulate exhaust is mentioned. Working together, these sub-systems increase the company's fuel savings. A significant disadvantage of this technique is that a high volume of catalyst is required.

  There are many other emission control technologies, some of which are not yet technically feasible.

Catalytic converters The problem of pollution, partly caused by automobiles, led to the 1970 Clean Air Act which required a 90% reduction in automobile exhaust. Some have considered the mandatory reduction to be controversial, but it was generally recognized as an advance for clean air and better health.

  The automotive industry initially resisted newly proposed regulations. Some of the resistance could have come from the industrial development of improved fuels. From the mid 1920s to the mid 1980s, automotive gasoline fuel contained the additive tetraethyl lead (TEL). TEL has improved fuel performance by preventing premature ignition in the engine cylinders. Pre-ignition occurs when the fuel / air mixture ignites prematurely in the combustion chamber of the engine. This causes damage to the engine and knocking causes efficiency and power reduction.

  To achieve the reduced emission standards set by the government, engineers invented catalytic converters. Catalytic converters were added to vehicle exhaust systems starting around 1976. Catalytic converters were effective in reducing emissions to some extent. However, common gasoline formulations containing TEL hindered the function of the catalytic converter. The TEL was eventually removed from the fuel because the TEL in the fuel harmed the catalytic converter metal catalyst.

Many people may notice that many vehicles have catalytic converters, which is a technical part that is generally not properly evaluated. The purpose of the catalytic converter is to remove pollutant exhaust gases from low hazardous compounds (eg nitrogen (N ₂ , which constitutes about 78% of the atmosphere), water (H ₂ O) and carbon dioxide (CO ₂ , in plants) Conversion or conversion into photosynthetic products)).

Catalytic converters are used to facilitate the conversion of unwanted pollutants to relatively innocuous molecules (eg, N ₂ , H ₂ O and CO ₂ ). Basically, catalytic converters provide a surface where pollutants are converted to relatively harmless materials. The catalyst allows the reaction to proceed faster (or at a lower temperature) by reducing the required activation energy. However, the catalyst is not exhausted in the reaction and can be reused (unless the catalyst is disabled).

Typical pollutants in the exhaust include nitrogen oxides (NO _x ), unburned hydrocarbons, carbon monoxide and particulate matter. Nitrogen oxides are reduced to produce nitrogen. If NO or NO ₂ molecule is in contact with the catalyst, the catalyst encourage the removal of nitrogen from the molecule, liberating oxygen in the form of O _2. The nitrogen atoms attached to the catalyst then react to produce N ₂ gas: 2NO → N ₂ + O ₂ and 2NO ₂ → N ₂ + 2O ₂ .

Unburned hydrocarbons, carbon monoxide, and particulate matter can be further oxidized to produce non-polluting materials. For example, carbon monoxide is treated as follows: 2CO + O ₂ → 2CO ₂ .

  The overall result of the catalytic converter is to complete the combustion of fuel to non-pollutants.

  Conventional catalytic converters have many limitations regarding their effectiveness for contaminant removal. For example, if conventional catalytic converters are placed too close to the engine, they can thermally decompose due to overheating or sudden changes in temperature. As such, the conventional catalytic converter filter is an engine exhaust manifold that is optimally located to utilize in situ high temperatures before it cools down due to radiative cooling from the high heat transfer properties of the exhaust pipe material. It cannot be placed near or inside. Engine vibrations and temperature changes that are near and inside the exhaust manifold can fatigue conventional filter materials and dramatically shorten the life of the filter. In addition, some catalysts applied to conventional filters may be less efficient or even fail at high temperatures (ie, temperatures above 500 ° C.). Therefore, the conventional catalytic converter filter is usually configured in an exhaust path located away from the engine.

Catalytic Converter and Particle Filter Structure The components and materials of the catalytic converter are shown schematically in FIGS. 4a and 4b. The catalyst substrate is held in a converter shell (also called a canister) using a packaging mat (most often made of ceramic fibers). The converter is connected to the vehicle's exhaust system via an end cone that can be welded to the shell or formed as one piece with the shell by converter packaging technology. The other components shown in the schematic-end seals and / or steel support rings-are optional; they are usually not present in modern passenger car converters, but more demanding applications It may be required in (eg tightly coupled converters, large converters for large engines, or diesel particulate filters). Catalytic converters, particularly in gasoline applications, can also be equipped with a steel heat shield (not shown in the schematic) to protect adjacent vehicle components from exposure to excessive temperatures.

  In general, a catalytic converter consists of at least five major components: 1) substrate; 2) catalyst coating; 3) washcoat; 4) mat; and 5) canister. A typical catalytic converter is shown in Figure X. For certain applications, the catalyst coating is optional, as will be discussed in more detail below.

Substrate A substrate is a solid surface on which contaminants can be converted to non-pollutants. Physically, the substrate reacts with each other in any physical state (eg solid, liquid or gas), providing an interface for several molecular species. The substrate generally has a large surface area to provide a large area where contaminants can be converted to non-pollutants.

  Over the past decades, many different materials and designs have been tested to act as substrates for chemical reactions. For example, main physical structures include honeycomb monoliths and beads (see FIG. 1). A honeycomb structure usually contains many grooves that run parallel to each other along the length of the substrate. The substrate has grooves that run the length of the substrate. The width of the groove often varies depending on the material of the substrate and the application in which it is used. These grooves allow exhaust gas to flow from the engine through the catalytic converter and out through the exhaust pipe. While the exhaust gas flows through the substrate groove, the pollutant molecules are converted to non-pollutant molecules by chemical reactions and physical changes.

  In the bead structure, the substrate is made from a collection of small beads (similar to putting a lump of jelly beans in a tube). The exhaust can flow around the beads (through grooves and cracks). When the exhaust gas hits the beads, the pollutants are converted to non-pollutants. The bead structure was one of the initial attempts to maximize the surface area of the substrate to which the exhaust molecules were exposed.

  Many different materials have been used as substrates. Examples of these include ceramics, fiber reinforced ceramic matrix composites (FRCMC), foams, powder ceramics, nanocomposites, metals, and fiber mat type substrates. The most commonly used is a ceramic called cordierite, which is manufactured by Corning. Cordierite is a ceramic formed from refractory powder. The FRCMC is an open cell foam where the catalyst is constructed on the cell walls and the foam is small so that it must exit through the cell path of the foam in which exhaust gas is present. Configured indoors. Foams are solids that contain many pores formed by bubbles from gas and fired hollows. Powder ceramic substrates are different from cordierite and related ceramics, in which case the powder ceramic is formed from sintered ceramic powder. A nanocomposite is a material that uses nanopowder and / or nanofibers. Metals can also be used as a substrate. In general, a thin sheet of corrugated metal foil such as steel is wound into a honeycomb-like structure. The fiber mat type substrate is a material woven on a small scale. Certain fiber mat type substrates utilize 3M NEXTEL fibers. Furthermore, “two-dimensional” nonwoven fiber composites have also been tried, but in this case the honeycomb structure is formed using pleat formation and / or corrugated winding (e.g. Patent Document 1, Patent Document 2). And Patent Document 3).

Catalytic coating The third component of modern catalytic converters is the catalytic coating. As the name implies, the catalyst coating is the component that actually catalyzes the conversion of contaminants to non-pollutants.

  A catalyst is usually defined as a substance that affects the rate of a chemical reaction but is not one of the original reactants or end products, ie it is not consumed or altered in the reaction. In some known catalytic reaction mechanisms, the catalyst uses the reactants to form an intermediate compound that is recovered during the course of the reaction. Many other catalytic processes are not fully described or understood in their entirety. There is no principle governing the selection and preparation of the catalyst for a particular purpose. Much of the development in this technical field is achieved through a thorough research program involving the testing of myriad materials. Catalysts are widely used in chemical and petrochemical processes to promote reactions that are otherwise too slow or require high temperatures to obtain good efficiency. Catalysts are also used to convert harmful components of engine exhaust gases (eg, hydrocarbons and carbon monoxide) into harmless materials (eg, carbon dioxide and water vapor).

  A catalyst is a substance that has the ability to accelerate certain chemical reactions between exhaust gas components. In emission control catalysis, solid catalysts are used to catalyze gas phase reactions. Catalytic effects and observed reaction rates are maximized by providing good contact between the gas phase and the solid catalyst. In catalytic reactors, this is usually achieved by providing a high catalyst surface area by finely dispersing the catalyst on a high specific surface area support (support).

  The catalyst coating is applied to the substrate after the substrate is formed. The coating forms a layer on the surface of the substrate, and the layer contains a catalyst. Different types of catalysts are required depending on, for example, chemical reactions, required applications, temperature conditions, economic factors, and the like. Many metal catalysts are known in the art. For example, the most commonly used are platinum, palladium and rhodium. Significant research has been done to develop new catalysts.

The rate of chemical reactions, including catalytic reactions, generally increases with temperature. The strong dependence of conversion efficiency on temperature is a unique feature of all emission control catalysts. A typical relationship between the catalyst conversion of pollutants and the temperature is shown as a solid line (A) in FIG. The conversion (nearly 0 at low temperature) increases gradually and then more rapidly, reaching a plateau at high gas temperatures. When considering the combustion reaction, the term ignition temperature is generally used to characterize this behavior. Catalytic ignition is the minimum temperature required to initiate a catalytic reaction. Due to the gradual increase in reaction rate, the above definition is not very accurate. According to a more precise definition, the ignition temperature is the temperature at which conversion reaches 50%. Its temperature is _often represented by _{T 50.} When comparing the activities of different catalysts, the most active catalyst is characterized by the lowest ignition temperature for a given reaction.

  In some catalyst systems, as shown by the dotted line (B) in FIG. 4, increasing the temperature can only increase the conversion efficiency up to a certain point. Further temperature increases cause a decrease in catalyst conversion efficiency, despite increasing the reaction rate. The decrease in efficiency is usually explained by other competing reactions that drastically reduce the concentration of reactants, or by thermodynamic reaction equilibrium forcing.

  The temperature range corresponding to high conversion efficiency is often referred to as the catalyst temperature window. This type of conversion curve is typical for selective catalytic processes. Good examples include selective reduction of NO with hydrocarbons or ammonia.

Another important variable that affects the conversion efficiency is the size of the reactor. The gas flow rate through the catalytic reactor is expressed as space velocity (SV), depending on the size of the reactor. The space velocity is defined as the volume of gas measured per unit time at standard conditions (STP) per unit volume of the reactor, as shown below: (3) SV = V / V _{r where} , V is located in the volumetric gas flow rate at ^{STP (m 3 / h);} V is the reactor volume ^{(m 3);} SV generally has a dimension of the reciprocal of the time represented by 1 / h or ^{h -1} ).

  In various catalyst emission control applications, the space velocity is in the range of 10,000 1 / h to 300,000 1 / h. The space velocity for the monorisk reactor is calculated based on their external dimensions (eg, the diameter and length of the cylindrical ceramic catalyst substrate). Since this method does not take into account the geometric surface area of the substrate, cell density, wall thickness or catalyst amount, this method is not always suitable for catalyst comparison. Nevertheless, this method is a commonly used and widely accepted industry standard.

Typical platinum amounts in filters used for off-road engines throughout the 1990s ranged from 560.7 to 801 kg / m ³ (35 to 50 g / ft ³ ). These filters incorporated in relatively high pollution engines required a minimum temperature of about 400 ° C. for regeneration. Later, it was found that when catalytic filters were applied to very clean city buses and other highway vehicle engines, these filters could be regenerated at much lower temperatures. However, higher platinum levels were required to support low temperature regeneration. Filters used for clean engine low temperature applications typically have platinum amounts of 810 to 1,201.5 (50 to 75 g / ft ³ ).

Washcoat In most cases, the catalyst coating includes a washcoat as a fourth component. The washcoat is applied to the surface of the substrate, thereby increasing the surface area of the substrate. The washcoat also provides a surface to which the catalyst adheres. Metal catalyst is this porous high surface laminate of inorganic support (ie washcoat—the term “catalyst support” can be used to mean ceramic / metal substrate as well as support / washcoat material) It can be impregnated on top.

  Many materials can be used as washcoats. Substances widely used for the catalyst support include activated aluminum oxide and silicon oxide (silica).

  The washcoat is a porous high surface laminate that is bonded to the surface of the support. Its exact role (which is indeed very complex) is not clearly understood or explained. The main function of the washcoat is to provide the very high surface area required for the dispersion of the catalytic metal. Furthermore, the washcoat can be physically separated to prevent undesired reactions between components of complex catalyst systems.

Examples of the washcoat material include inorganic base metal oxides (eg, Al ₂ O ₃ (aluminum oxide or alumina), SiO ₂ , TiO ₂ , CeO ₂ , ZrO ₂ , V ₂ O ₅ , La ₂ O ₃ and zeolite). It is done. Some of them are used as catalyst supports. Others are added to the washcoat as accelerators or stabilizers. Still others exhibit their own catalytic activity. A good washcoat material is characterized by a high specific surface area and thermal stability. Specific surface area is measured by using a nitrogen adsorption measurement technique together with mathematical modeling known as the Brunauer, Emmet and Teller (BET) method. Thermal stability is assessed by exposing a sample of a given material to elevated temperatures in a controlled atmosphere, usually in the presence of oxygen and water vapor. The loss of BET surface area remeasured at different time intervals during the test indicates the degree of thermal degradation of the test material.

  The washcoat can be applied to the catalyst support from a water-based slurry. The wet washcoat portion is then dried and calcined at an elevated temperature. The quality of the catalyst washcoat can significantly affect the performance and durability of the finished catalyst. Thereafter, by impregnation (ie, “dipping” the washcoat porosity in the catalyst solution), the precious metal will be applied to the washcoat treated portion and the amount of washcoat will determine the amount of precious metal catalyst in the finished product. Therefore, it is very important that the wash coating process yields a very repeatable and uniform washcoat layer. Details regarding the wash coating process and its parameters are protected as a trade secret by all catalyst manufacturers.

The canister substrate is packaged in a canister (eg, a steel shell) to form a catalytic converter. The canister performs many functions. The canister holds the catalyst substrate and protects the substrate from the external environment. Furthermore, the canister allows the exhaust gas to flow through and / or over the catalyst substrate.

  The catalyst substrate is also packaged inside the muffler, which is then referred to as a “catalytic muffler” or “catalytic muffler”. In this case, one steel canister holds both the catalyst and noise absorbing components (eg baffles and perforated tubes). Catalytic mufflers can provide a greater space saving design compared to catalytic converter and muffler combinations.

  The catalyst substrate is typically placed inside a canister having a three-dimensional configuration made according to one of several methods, including clamshells, tourniquets, shoeboxes, padding and garments, as shown in FIG. It is burned.

In addition to mat canisters, mat materials are often used to package catalyst substrates in canisters. Packaging mats usually made from ceramic fibers can be used to protect the substrate and to evenly distribute the pressure from the shell. The mat often contains vermiculite, which expands at high temperatures, thus compensating for the thermal expansion of the shell and providing adequate retention under all operating conditions.

  For example, a ceramic monolith is encased in a specific packaging material that is held securely in a steel housing to evenly distribute the pressure and prevent cracking. Ceramic fiber mats are most commonly used in the packaging of catalytic converters for gasoline and diesel applications. These packaging mats can be classified as follows: expanded (thermally expandable) mats; conventional (high vermiculite); reduced vermiculite; non-expandable mats; or hybrid mats.

Insulation In many applications, catalytic converters are used to avoid damage to surrounding vehicle components (eg, plastic parts, fluid hoses), or in converters deployed near the engine. In order to prevent the increase, it must be insulated. One method of converter thermal management is to use a steel heat shield constructed around the converter body. An alternative method is to provide a thermal insulation layer inside the shell by (1) increasing the thickness of the component mat or (2) providing an additional layer of dedicated low thermal conductivity thermal insulation. . Although heat shields have traditionally been used in the underfloor position, it has been suggested that increased mat thickness provides the best solution for converters incorporated into the engine compartment (1). One advantage of using a mat that is thicker than the thermal shield is the lower average mat temperature, which minimizes the risk of breaking the vermiculite mat in tightly coupled gasoline engine applications.

Particle Trap Another device for removing contaminants from exhaust gases is a particle trap. A common particle trap used in diesel engines is the diesel particle trap (DPT). The main purpose of the particle trap is to filter and trap various sizes of particulate matter from a fluid stream such as an exhaust gas stream. The effectiveness of a particle filter is generally measured by its ability to filter different sizes of PM (eg, PM-2.5 and PM-10).

  Diesel traps are relatively effective at removing carbon soot from diesel engine exhaust. The most widely used diesel trap is a wall flow filter that filters diesel exhaust by capturing soot on the porous wall of the filter body. Wall flow filters are designed to provide nearly complete filtration of soot without significantly hindering the exhaust flow.

  As the soot layer collects on the surface of the inlet groove of the filter, the lower permeability of the soot layer causes the filter pressure drop and the gradual increase in the back pressure of the filter to the engine, causing the engine to work harder and thus the engine Affects operational efficiency. Eventually, the pressure drop is unacceptable and the filter needs to be regenerated. In conventional systems, the regeneration process involves heating the filter to begin burning carbon soot. In certain situations, regeneration is accomplished under engine management control conditions, whereby slow combustion is initiated and lasts for several minutes, during which time the temperature in the filter ranges from about 400-600 ° C. up to about 800-1 The temperature rises to 000 ° C.

  In certain applications, the exhaust stream carries the heat of combustion below the filter, so the maximum temperature during regeneration is at the outlet of the filter due to the cumulative effect of soot combustion waves traveling from the inlet face to the outlet face of the filter. Tends to occur near the edge. Under certain circumstances, so-called “uncontrolled regeneration” can occur when the start of combustion occurs at the same time as or immediately after the high oxygen content and low flow rate (eg, engine idling conditions) in the exhaust gas. During uncontrolled regeneration, soot combustion results in rapid temperature changes in the filter that can undergo thermal shock and pyrolysis, or even melting. The most common temperature gradients observed are the radiant temperature gradient where the center temperature of the filter is higher than the rest of the substrate and the axial temperature gradient where the outlet end of the filter is higher than the rest of the substrate.

  In addition to capturing carbon soot, the filter also traps metal oxide “ash” particles held in the exhaust gas. Typically, these ash deposits are derived from the unfired lubricating oil that accompanies the exhaust gas under certain conditions. These particles are not flammable and are therefore not removed during regeneration. However, if the temperature during uncontrolled regeneration is high enough, the ash can eventually sinter into the filter, or even react with the filter, resulting in partial melting.

  Obtaining a filter that offers improved resistance to melting and thermal shock damage so that the filter survives very low frequency but more stringent uncontrolled regeneration as well as multiple controlled regenerations over its lifetime Is considered an advance in the technical field.

Continuous Regeneration Trap One conventional method for catalytic conversion is a diesel particle trap (“DPT”). The DPT is a filter that collects particulate matter in the exhaust gas. The collected particulate matter must then be burned out before the filter is clogged. The combustion of particulate matter is called “regeneration”. Some conventional methods exist for the regeneration of DPT. First, the application of a noble or base metal catalyst to the filter surface can reduce the temperature required for the oxidation of particulate matter. Secondly, the filter is placed in front of chamber containing an oxidizing catalyst to produce NO _2, this is helps to burn the particulate matter. Third, the system can utilize a fuel-carrying catalyst. Finally, an external source of heat is used, in which case the soot burns at 550 ° C. without a catalyst or at about 260 ° C. with a noble metal catalyst. Regeneration requires some maintenance to leave ash residues after carbon combustion and clean the filter.

Yet another conventional method utilizes a diesel oxidation catalyst (“DOS”). DOS is a catalytic converter that oxidizes CO and hydrocarbons. Hydrocarbon activity extends to particulate polycyclic aromatic hydrocarbons (“PAH”) and soluble organic fractions (“SOF”). Catalyst formulations have been developed that selectively oxidize SOF while minimizing the oxidation of sulfur dioxide or nitric oxide. However DOC produces a sulfate, may increase the emission of NO _2.

  The function of the catalyst in the catalyzed diesel particulate filter (CDPF) is typically in the range of 300-400 ° C. of diesel particulate matter (DPM) at exhaust temperatures experienced during normal engine / vehicle operation. In order to promote the regeneration of the filter by oxidation, the soot combustion temperature is lowered. In the absence of a catalyst, DPM can be oxidized at temperatures above 500 ° C. at a readily appreciable rate, but this is rarely observed in real diesel engines. Reported substrates used for these catalytic applications include cordierite and silicon carbide wall flow monoliths, wire mesh, ceramic foam, ceramic fiber media, and the like. The most common type of CDPF is a catalytic ceramic wall flow monolith.

  Catalytic ceramic traps were developed in the early 1980s. Their first use included diesel cars and then underground mining machinery. The catalytic filter was commercially introduced in a Mercedes vehicle sold in California in 1985. Mercedes models 300SD and 300D with turbocharged engines were equipped with a filter with a diameter of 143.76 mm x 152.40 mm (5.66 inches x 6 inches) mounted between the engine and the turbocharger.

  The use of diesel traps on automobiles was later abandoned due to problems such as inadequate durability, increased pressure drop, and filter clogging. Today, catalytic ceramic traps are one of the most important diesel filter technologies, although not all of these problems have been solved. CDPF is increasingly being used in many large applications (eg city buses and public diesel trucks). Over the years, limited amounts of catalytic filters have been used in underground mining (South America and Australia) and in certain stationary engine applications.

  Catalytic ceramic filters are commercially available for many highway, off-road and stationary engine applications, both as OEM and aftermarket products. The list of suppliers includes Engelhard, OMG dmc2, as well as several smaller emission control manufacturers (mainly dedicated to the off-road market).

  The main component of conventional filters is a ceramic (typically cordierite or SiC) wall flow monolith. The porous wall of the monolith is coated with an active catalyst. As diesel exhaust aerosol penetrates the walls, soot particles are deposited in the wall pore network as well as on the inlet groove surface. The catalyst promotes DPM oxidation by oxygen present in the exhaust gas.

Pressure drop The flow of exhaust gas through a conventional catalytic converter creates a substantial amount of back pressure. Increased back pressure in the catalytic converter is an important attribute for the successful operation of the catalytic converter. If the catalytic converter is partially or totally clogged, it causes a restriction in the exhaust system. Subsequent increases in back pressure can cause severe declines in engine performance (eg, horsepower and torque) and fuel economy, and can even cause the engine to stop after it has started if the shutoff is severe. Traditional efforts to reduce pollutant emissions are very costly, both due to the cost of the material and the retrofit of the original engine with appropriate filters or the cost of manufacturing and material.

  The high filtration efficiency of the wall flow filter is obtained at the expense of a relatively high pressure drop that increases with filter volume. Initially, the filter is clean. As the particles begin to deposit within the pores in the monolith wall (depth filtration), the pressure drop begins to increase with time in a non-linear manner. This phase is referred to as the initial loading phase, during which pore attributes such as permeability and filter porosity change constantly due to incremental soot deposition within the pore network. The pore filtration capacity becomes saturated and soot begins to deposit as a layer inside the inlet monolith groove (cake filtration phase). A linear increase in pressure drop with time (and with soot) is observed during this period. One characteristic that changes is the thickness of the heel layer. Some authors distinguish between the point at which particles begin to deposit on the groove surface and the intermediate short-term transition phase until the soot layer is well established (Non-Patent Document 4 and Non-Patent Document 5).

  Pressure drop modeling in the clean filter substrate was performed. The developed relatively simple model shows excellent agreement with the experimental results (Non-Patent Document 2 and Non-Patent Document 3). However, most filter pressure drops in practical applications are caused by soot deposition. In certain applications, the pressure drop of a clean wall flow filter can be in the range of 1-2 kPa, while a load filter pressure drop of 10 kPa can be considered low to moderate in certain circumstances.

  The total pressure drop of the particle load filter can be divided into four components: pressure drop due to sudden contraction and expansion at the inlet and outlet from the filter; pressure drop due to groove wall friction; Pressure drop due to permeability of the particle layer; and pressure drop due to wall permeability.

  The pressure drop due to sudden contraction and expansion at the inlet and outlet from the filter is similar to the same component in the clean filter, except that the effective groove size (hydraulic diameter) is Therefore, smaller and more gas shrinkage occurs.

  The pressure drop due to groove wall friction also increases with respect to the clean filter sequence due to the reduction of the groove hydraulic diameter. For thick ridges, the ΔP groove can be a very significant aid to the total pressure drop.

  The pressure drop due to the permeability of the particle layer (ΔP particles) can be a significant aid to the total pressure drop.

  The pressure drop (ΔP wall) for wall permeability is also higher here than in the case of a clean filter, since the wall holes are partially filled with soot. The increase in ΔP wall that can be attributed to the initial soot loading phase in the hole is represented by ΔPI in FIG.

The total pressure drop can be expressed as:
ΔP = ΔP inlet / outlet + ΔP groove + ΔP particle + ΔP wall

  Mathematical modeling of pressure drop in heavy duty diesel filters is a complex and difficult task. Important characteristics of the soot (eg, permeability and packaging density) depend on the application, engine operating conditions and other parameters. Efforts to simulate pressure drop in wall flow filters are ongoing and incrementally more refined models are under development. Predicting the actual load may require a theoretical model of the regeneration process itself.

Types of catalytic converters and particle filters Catalytic converters can be classified based on a number of factors: a) the type of engine in which the converter is used, b) its position depending on the engine, c) the type of catalyst used in the converter. Number and type, and d) the type and structure of the substrate used. In addition, each of these catalytic converters is often used in conjunction with other emission control devices such as CRT, EGR, SCR, ACERT, and other devices and methods.
engine

  Catalytic converters are used in at least two types of engines: gasoline engines and diesel engines. Within these two general classes, there are many types of special gasoline and diesel engines. For example, gasoline engines and diesel engines with various displacements and horsepower are manufactured. Some engines are equipped with turbochargers and / or intercoolers. Most passenger car and truck engines are water-cooled, while many motorcycle engines are air-cooled. Some utilities require high available horsepower, while others maximize fuel economy. All of these variables, in addition to others, can affect the level of pollutants that are produced during fuel combustion. In addition, there are different regulatory requirements regarding emission standards, for example by the use of engines on road, off road or stationary.

Position Catalytic converters can theoretically be configured anywhere along the engine exhaust flow. However, the physical properties of conventional catalytic converters limit their location. Most commonly in vehicles, the catalytic converter is constructed some distance from the engine block, near the muffler, and directly under the car body. Catalytic converters are usually not configured near the engine because catalytic converters can fail for several reasons. Such reasons include extreme temperatures near the engine, thermal shock, mechanical vibration, mechanical stress, and space limitations. Furthermore, the physical settings of the stationary engine may limit the position of the catalytic converter or particle filter.

  For example, the 2004 FOCU. S. In (registered trademark), Ford Motor Company handled mani-catalytic converters in the same way that Honda Motor Corporation did in one of its samples. These systems actually exist adjacent to rather than part of the manifold. The high temperature energy and extreme vibration energy generated by the cylinder rapid combustion and moving parts, when placed in the manifold, exposes a typical catalytic converter to excessive heat and physical shock. In addition, a design for the mani-catalytic converter was proposed by Northup Grumman Corporation in US Pat. Even the latest cordierite base material seems to be challenging to withstand such an environment.

  In other applications, such as motorcycles (eg Harley-Davidson), the presence of a catalytic converter at a location can cause severe damage to the user. Due to the high operating temperature of the catalytic converter, it may be preferable to use a catalytic converter that is less susceptible to damage to the user (eg, a small catalytic converter, a converter that does not move when hot, etc.).

In some cases, the exhaust system (eg, in a passenger car) may contain more than one catalytic converter or particle filter along its exhaust stream (see FIG. 4). For example, the exhaust system may have an additional catalytic converter between the engine and the main catalytic converter. This configuration is called a pre-catalytic converter. The pre-catalytic converter may have a denser configuration. Another setting is a post-catalytic converter, which has a secondary catalytic converter behind (after) the main catalytic converter. Post-catalytic converters are sometimes also used for equipment modified catalytic converters.
2-way vs. 3-way vs. 4-way

  Catalytic converters can generally be classified as 2-way, 3-way or 4-way converters. At least the following types of converters are commercially available: oxidation converters, 3-way converters (without air), 3-way plus oxidation converters, and 4-way converters.

  An oxidation (2-way) converter represents an early generation converter designed to oxidize hydrocarbons (HC) and carbon monoxide (CO). Although these units represent most basic forms of catalytic converter technology, they are still viable environmental pollution reduction options in some areas. Oxidation converters usually contain platinum or palladium. However, other non-noble metals can be used as well.

In the early 1980s, most vehicle manufacturers began using converters designed to reduce NO _x in addition to oxidizing HC and CO. These 3-way converters used with computer controlled engine systems and oxygen sensors were used to more accurately control the air to fuel ratio. Three compounds: HC, for processing CO and NO _x, these converters are called 3-way converter.

Most modern passenger cars are equipped with “3-way” catalytic converters that typically have one or more substrates in tandem using Corning clay extrusion technology. “3-way” refers to three regulated exhausts that help the converter reduce: carbon monoxide, volatile organic compounds (VOC (eg, non-burning hydrocarbons)) and NO _x molecules. Such converters use two different types of catalysts: a reduction catalyst and an oxidation catalyst.

In 3-way catalytic converters, the reduction catalyst is usually found in the first stage of the catalytic converter and serves to return the oxides of nitrogen produced in the combustion chamber. It generally uses platinum and rhodium to help reduce the NO _x exhaust. The oxidation catalyst, which can be composed of a metal such as platinum and / or palladium, is generally located in the second region of the catalytic converter.

  A 3-way converter having a reduction catalyst and an oxidation catalyst together in one housing is sometimes referred to as a 3-way plus oxidation converter. These converters use air injection between the two substrates. This air injection helps the oxidation chemical reaction.

The 4-way converter processes carbon monoxide, nitrogen oxides, non-burning hydrocarbons and particulate matter. Examples of these include QuadCAT 4-way catalytic converters (manufactured by Ceryx). According to the manufacturer, four of the major sources of air pollution (ie NO _x , hydrocarbons, carbon monoxide and particulate matter), the level at which diesel engines can meet the 2002/2004 emission standards. It is a catalytic converter that reduces to Other examples include those described in Patent Document 5 and Patent Document 6.

  The catalytic converter, like other catalysts, facilitates the reaction by reducing the activation energy required to achieve the desired reaction. For example, if the particles require a temperature of 550 ° C. before reacting with oxygen and burning out in the presence of a catalyst, this same reaction only requires a temperature of 260 ° C. This low energy threshold can physically configure the catalyst system downstream from an engine with more space, even at lower temperatures. Otherwise, the catalyst system will need to be configured upstream with higher temperatures. However, if the catalyst system is configured near the engine, this is not feasible even with the latest technology, as it is likely to damage the substrate.

Diesel engines produce exhausts that exhibit relatively low CO production and low hydrocarbon production while having high NO _x and particulate concentrations due to high temperature and high pressure. Compressive combustion is less complete than that using gasoline engine sparks. However, because of the relatively low quality mixture having a high air content, diesel can provide better gas mileage than a gasoline engine. 3-way catalysts do not work well in diesel exhaust due to excess air. NO _x reduction catalysts typically require a well-maintained stoichiometric ratio of fuel to air that cannot be easily implemented in a diesel combustion engine.

Catalytic converter technology can be applied to various applications including internal combustion engines and stationary combustion engines. An internal combustion engine is the most common engine used for vehicles. The catalytic converter is incorporated as a device in the exhaust system of the vehicle so that the entire exhaust gas stream passes through the substrate and comes into contact with the catalyst before being discharged from the rear exhaust pipe. However, catalytic converters can also be part of a rather complex system that encompasses a variety of active strategies (eg, reactant injection at the catalyst front surface, or complex engine control algorithms). Examples include many of the diesel catalyst systems have been developed for the reduction of the NO _x and the like. The attributes of simplicity and passive properties listed among the advantages of the catalyst can no longer be adapted to those systems.

  Prior attempts to reduce pollutant emissions can be very costly, in part due to the cost of materials and, in some applications, to retrofit or manufacture the original engine with a suitable filter. .

Advances in Catalytic Converter and Particle Filter Technology The invention that led to the advancement of catalytic converters was the development of Corning for extruded cordierite, honeycomb and monoliths (see Patent Document 7). Since the 1970s, catalysts from the noble and base metal families (platinum, palladium, Using this approach using rhodium, etc.) over a billion pounds of pollutants have been removed from the exhaust stream. Changes and improvements to this core technology have evolved over the years since, including changes in the construction of catalytic converters and in their composition and manufacturing methods. However, to date, there remains a fundamental deficiency that has not been overcome. In recent years, the state of the art has reached physical and economic limits, and only minor improvements have been made at great expense.

Current substrate limitations While the current state of catalytic converter and particulate filter technology is useful to some extent to reduce exhaust pollution, there are certainly disadvantages to the general technology. There are also characteristics that cannot be achieved with current catalytic converters. Some disadvantages are inherent in the type of substrate used. Thus, improved substrates for use in catalytic converters or particle filters are a significant advance in the basic physical and chemical attributes of materials used as catalytic substrates in catalytic converters. Furthermore, the improved substrate dramatically increases its quality, allowing manufacturers and users to more easily meet 2007 and 2010 and even later emission standards.

  Conventional monolithic catalytic converter substrates are generally formed by an extrusion process. This method, which is complex and relatively expensive, has been used for the last 25 years. However, the extrusion method has limitations. There is a limit as to how the grooving can be made in the material and still maintain quality control. The extrusion method also limits the shape of the catalytic converter to a cylindrical or parallelogram shape or a shape having side surfaces parallel to the extrusion axis. This shape limitation was not a problem with conventional emission standards. However, the need to design catalytic converters and particle filters that can reach near zero emission performance can require non-linear and / or non-cylindrical filter designs and vehicle integrity.

  Wall thickness reduction increases surface area, and in some cases reducing wall thickness from 0.006 inches to 0.002 inches increases surface area by 54%. By increasing the surface area, more particulate matter can be deposited in the low volume. FIG. 1 shows a prior art honeycomb configuration 102 formed in a ceramic filter element 100 designed to increase the surface area of a catalytic converter. The honeycomb structure 102 is formed using an extrusion method in which long grooves having their principal axes are formed in parallel with the extrusion action. These groove openings face the intruding exhaust air flow.

  Advances in technology have made it possible to produce ceramic cordierite substrates with reduced wall thickness. 400 / 6.5 with 400 cpsi cell density and 0.0065 inches (or about 0.17 mm), the former standard configuration for passenger car applications, is becoming a thinner wall (0.0055 to 0.004 mil) substrate. Replaced. However, the physical limits of this material are approaching. Due to the physical properties of ceramics, especially cordierite, the use of a substrate made of cordierite ceramic with even thinner walls is impractical. Thinner wall materials cannot meet other required properties (eg, durability, heat resistance).

  Diesel catalysts, in part due to their large size, often have thicker walls than their automotive equivalents. Because diesel wall flow filters generally have thicker walls, there is a physical limit on the grooves / square inch that these filters can have. In general, there are no commercial diesel wall flow filters with more than 200 grooves / square inch.

  Another limitation of commonly available substrates is their reduced catalytic efficiency at low temperatures. If the converter system is cold, at such an engine start, the temperature is not high enough to initiate a catalytic reaction. Cordierite, silicon carbide, and various metal substrates used in catalytic converters and sold by Corning, NGK, Denso and other companies today have excellent mechanical strength and resistance to thermal shock and vibration. Made from strong, dense material. However, these materials require time to absorb heat after initiation until a temperature sufficient for catalytic reaction is reached. Due to the delay in starting the catalytic reaction, it is estimated that about 50% of all exhaust from modern engines is released to the atmosphere during the first 25 seconds of engine operation. Even small improvements during these critical “cold start-up” seconds can dramatically improve the amount of contaminants that are successfully treated per year. Although efforts have been put into addressing this problem, there remains a need for a catalytic converter that can reduce emissions during this cold start period. Even in the most advanced and costly state of the art, cordierite-based catalytic converters require approximately 20 seconds to start.

  In order to achieve the reaction temperature more quickly, attempts have been made to move the converter closer to the engine exhaust manifold where higher temperatures are available more quickly and also help drive the reaction more intensely during operation. Because the available space under the vehicle hood is limited, the size of the converter system and thus the amount of throughput that can be successfully processed is limited. Common substrates cannot be used effectively in the vehicle's engine compartment. In addition, it is not desirable to add additional weight to the engine compartment, many common substrates are dense, have limited porosity (about 50% or less), and are heavy to handle large exhaust power Requires a large volume system. In addition, substrates such as cordierite are susceptible to melting under many operating conditions, thereby causing clogging and increased back pressure.

Other methods of compensating for cold start include complex adsorption systems that temporarily store NO _x and / or hydrocarbons so that the converter can be processed once it reaches a critical temperature. Some of these systems require parallel pipes and complex adsorption surfaces, additional valves and control mechanisms, or multiple different washcoats used to attach the catalyst to the substrate and isolate the reaction environment. . This problem is particularly under consideration in diesel engines where large volumes of soot particles, NO _x and SO _x need to be trapped. In some large industrial diesel engines, a rotating bank of diesel particle traps is used to collect, store and substantially process the particles (in still other systems, NO _x is stored and oxidant Used to convert CO to CO ₂ while NO _x is reduced to N ₂ ).

  Assuming regulatory restrictions on total emissions, a system that can easily save some of the 50% of the emissions produced during cold start is an expensive and complex working-around as described above. Eliminate the need for some. When used in conjunction with these workarounds, such a system can produce it in a substantially reduced exhaust. However, as explained above, conventional systems are generally complex and expensive, and tend to not fire and / or operate unpredictably.

  Another inherent limitation of conventional systems is the typical “residence time” required to burn out the particles. Given the large volume exhaust gas throughput during operation, as well as the speed at which the gas must flow, it is important that the converter can ignite quickly. Thus, a catalytic converter that can ignite quickly and withstand extreme thermal and vibration shocks and increase the internal temperature quickly during cold start greatly enhances the industry's potential to reduce emissions, 2007 And it will meet the upcoming environmental standards for 2010 and produce cleaner engine engines, truck engines, bus engines and heavy industry engines.

  If the substrate is also light, it also results in improved mileage statistics in the new vehicle. To date, however, no substrate has been identified that can handle many or all of these problems.

Design Considerations for Substrates for Catalytic Converters or Particle Filters Catalytic substrates are a critical component that affects the performance, toughness and durability of catalytic converter systems. Furthermore, the filtration substrate significantly affects the operational performance of the particle filter. Ideally, the substrate used in the catalytic converter or particle filter should have many attributes. These attributes include, but are not necessarily limited to, one or more of the following aspects: a) surface area; b) porosity / permeability; c) emissivity; d) thermal conductivity; f) Thermal attributes (eg, impact resistance, expansion and conductivity); g) density; h) structural integrity; i) efficiency of contaminant treatment; j) amount of catalyst required; and k) weight of system. Catalyst substrates or filtration substrates that optimize one or more attributes are an advance in the field of filtering fluids and catalyzing reactions.
U.S. Pat. No. 4,894,070 US Pat. No. 5,196,120 US Pat. No. 6,444,006 US Pat. No. 5,692,373 U.S. Pat. No. 4,329,162 US Pat. No. 5,253,476 US Pat. No. 4,033,779 U.S. Pat. No. 4,148,962 US Pat. No. 3,953,083 U.S. Pat. No. 3,795,524 U.S. Pat. No. 4,047,965 US Pat. No. 5,629,186 US Pat. No. 5,378,142 US Pat. No. 5,102,639 US Pat. No. 6,090,744 US Pat. No. 6,692,712 US Pat. No. 5,182,249 US Pat. No. 5,224,852 US Pat. No. 5,272,125 US Pat. No. 6,682,706 US Pat. No. 6,667,012 U.S. Pat. No. 4,529,718 U.S. Pat. No. 4,722,920 US Pat. No. 5,795,456 US Pat. No. 5,856,263 US Pat. No. 6,576,200 US Pat. No. 5,100,632 US Pat. No. 5,296,288 US Pat. No. 5,702,761 US Pat. No. 5,928,775 US Pat. No. 5,079,082 US Pat. No. 5,702,761 US Pat. No. 5,928,775 US Pat. No. 5,079,082 US Pat. No. 6,685,899 US Pat. No. 6,673,414 US Pat. No. 5,611,832 U.S. Pat. No. 4,148,962 US Pat. No. 6,613,255 US Pat. No. 5,296,288 U.S. Pat. No. 4,047,965 U.S. Pat. No. 3,549,473 US Pat. No. 4,686,128 US Pat. No. 6,605,259 US Pat. No. 5,692,373 European Patent Application No. 08484459 European Patent No. 091820 US Pat. No. 6,622,482 US Pat. No. 6,604,6004 US Pat. No. 6,341,662 U.S. Pat. No. 4,457,895 US Pat. No. 5,983,631 Said Zidat and Michael Parmentier, “Heat Insulation Methods for Manifold Mounted Converters,” Delphi AutoMomental Systems, Technical Center Lumin01, Technical CentreLux Masoudi, M.M. Et al., 2000, “Predicting Pressure Drop of Wall-Flow Diesel Particulate Filters Theory and Experiment”, SAE 2000-01-0184. Masoudi, M.M. 2001, “Validation of a Model and Development of a Simulator for Predicting the Pressure Drop of Diesel Particulate Filters,” SAE 2001-01-0911. Tan, J .; C. Et al., 1996, “A Study on the Regenerative Process in Diesel Particulate Trap Usage a Copper Fuel Additive”, SAE 960136. Versaevel, P.M. Et al., 2000, “Some Empirical Observations on Diesel Particulate Filter Modeling and Comparison Between Simulations and Experiments”, SAE 2000-01-0477. Leiser et al., “Options for Improving Rigidized Ceramic Heatshields”, Ceramic Engineering and Science Proceedings, 6, no. 7-8, pp. 757-768 (1985) Leiser et al., “Effect of Fiber Size and Composition on Mechanical and Thermal Properties of Low Density Ceramic Composite Insulation Materials,” NASA CPp. 23. 231-244 (1984) http: // www. epa. gov / otaq / inventory / r92009. available from pdf. S. Document number EPA420-R-92-009 issued by EPA Ogyu, K .; Et al., 2003. “Characterization of Thin Wall SiC-DPF”, SAE 2003-01-0377 Yuuki, K .; Et al., 2003, “The Effect of SiC Properties on the Performance of Catalyzed Diesel Particulate Filter (DPF),” SAE 2003-01-0383 Ichikawa, S .; Et al., 2003, “Material Development of High Porous SiC for Catalyzed Diesel Particulate Filters,” SAE 2003-01-0380) Leiser et al., “Options for Improving Rigidized Ceramic Heatshields”, Ceramic Engineering and Science Proceedings, 6, no. 7-8, pp. 757-768 (1985) Leiser et al., “Effect of Fiber Size and Composition on Mechanical and Thermal Properties of Low Density Ceramic Composite Insulation Materials,” NASA CPp. 23. 231-244 (1984) Kuisell, R.A. C. , 1996, “Butting Monoliths in Catalytic Converters,” SAE 960555. Li, F.M. Z. , 2000, “The Assembly Deformation and Pressure of Stuffed Catalytic Converter Accounting for the Hysteresis Behavior of Pressure 23. Density of Density. Eisenstock, G.M. , Et al., 2002, “Evaluation of SoftMount Technology for Use in Packaging Ultra Thinwall Ceramic Substrates”, SAE 2002-01-1097 Wendland, D.W. W. , Et al., 1992, “Effect of Header Truncation on Monolith Converter Emission Control Performance”, SAE 922340. Rajadurai, S .; , Et al., 1999. “Single Sea Stuffed Converter Design for Thinwall Substrates”, SAE 1999-01-3628. Olson, J.M. R. , 2004, “Diesel Emission Control Devices-Design Factors Affecting Mounting Mat Selection,” SAE 2004-01-1420.

[Summary of Invention]
Various embodiments are described here. These as well as other embodiments of the present invention are described in the Detailed Description section below.

  Nonwoven sintered refractory fiber ceramic (nSiRF-C) composites as described herein are used as improved substrates for catalytic converters, particle filters and related equipment and are shaped accordingly. The present inventors have discovered that.

  The inventors have also discovered that improved catalyst substrates and improved filtration substrates can be prepared from materials having specific attributes as described herein. For example, suitable attributes include high melting point, low thermal conductivity, low coefficient of thermal expansion, ability to withstand thermal and vibration shock, low density, and very high porosity and permeability. An exemplary material in one embodiment having these attributes is nSiRF-C.

  An example of a material with suitable attributes is an nSiRF-C composite material. An example of nSiRF-C is an alumina reinforced thermal insulation (“AETB”) material or similar material, which can be used in accordance with embodiments of the present invention as a catalyst substrate or filtration substrate. AETB materials are known in the art and include alumina boria silica (also known as alumina-boria-silica, aluminoborosilicate, and aluminoborosilicate) fibers, silica fibers, and alumina fibers. One generally known application for AETB is as an external tile on the space shuttle, which is ideal for shuttle reentry. AETB has never been used as a filtration substrate or a catalytic converter substrate.

  The inventors have realized that the attributes that make AETB desirable for the space industry are also preferred in combustion technology. Among other attributes, AETB has a high melting point, low thermal conductivity, low coefficient of thermal expansion, ability to withstand thermal and vibrational shock, low density, and very high porosity and permeability. This combination of desired attributes is lacking in common filtration substrates and catalytic converter substrates.

  nSiRF-C composites (eg, AETB and similar suitable substrates) are prepared, shaped, molded, cut and / or adapted to new forms suitable for use as particle filter substrates and catalytic converter substrates It has also been found that it can be (or otherwise physically modified).

  The present invention has many advantages over general techniques. First, the present invention provides improved air quality and respiratory health. The present invention can substantially reduce the possibility of carbon monoxide poisoning.

  Embodiments of the present invention can be used as a direct alternative for commonly used catalyst and filtration substrates, as well as catalytic converters and particle filters, and exhaust and engine systems. As described in the detailed description below, the substrate of the present invention provides many advantages over prior art substrates, and further eliminates many problems left unsolved by prior art substrates. Resolve. This translates into significant cost savings for some of the manufacturers. There is no need to redesign the exhaust system because the present invention can be used as a direct alternative to general technology. Thus, enhanced exhaust filtration and exhaust purification can be obtained with minimal investment in time, without the need to reorganize manufacturing plans and lines.

  The improved catalytic and filtration characteristics of the present invention require the use of less catalyst in certain embodiments. This advantage provides another cost saving because most catalysts used in related applications are expensive.

  The preferred thermal attributes of some embodiments of the present invention reduce and / or eliminate the need for certain portions of the exhaust system to address the heat rise associated with general catalytic converters and particulate filters. Thermal shielding and thermal insulation may not be required in certain embodiments of the present invention. The elimination of these components from the exhaust system and the vehicle only directly reduces costs (components are not used and thus low-cost production), but also indirectly (vehicle weight is reduced). Thus reducing fuel costs). Other benefits may include better performance, better mileage, and / or better horsepower.

  In some embodiments, conventional catalytic converters or particle filters are smaller, but can be replaced with the present invention with the same or better efficiency of removing contaminants. With smaller catalytic converters or particle filters, more space is available in the vehicle for other purposes. Furthermore, the filter or converter of the present invention is smaller, which reduces the overall weight of the vehicle.

  Another aspect of some embodiments of the present invention is a catalytic substrate suitable for use in a catalytic converter constructed in whole or in part on the engine head. The above-described catalytic converter, referred to herein as a head catalytic converter, has many advantages over the prior art. For example, conventionally, such head-catalytic converters are not practical due to the limitations of commonly available catalytic substrates. Common substrate cordierite will absorb too much heat. Because of the favorable thermal properties of the substrate of the present invention, a head catalytic converter comprising the substrate will reduce turbo thermal stress on the turbocharger and / or intercooler, if present.

  The head catalytic converter also does not require additional external hardware such as a heat shield. The use of a head catalytic converter makes it possible to maintain a favorable appearance of the engine and product, for example in a motorcycle. In some embodiments, the use of a head catalytic converter also reduces external discoloration of exhaust systems such as mufflers and header pipes. Many additional advantages of the head catalytic converter in certain embodiments include one or more of the following: increased safety; the intercooler would otherwise start moving back and hence the intercooler's Filter particles that improve life and provide cost savings; no mat required for certain embodiments; rattling sound in thermal shields can be reduced or eliminated by use of a head catalytic converter; and head Catalytic converters can reduce the required muffler size.

  In other embodiments of the head catalytic converter, the smaller the particulate matter, the more efficiently it burns out. If the head catalytic converter fails, only one small catalytic converter may need to be replaced. Head catalytic converters also provide these advantages for boats, ships, motorcycles, leaf blowers and the like.

  In addition, different embodiments of the present invention provide one or more of the following advantages over the prior art: improved appearance; avoidance of additional hardware; additional hardware (necessary for more stringent regulations) Is not necessary with the present invention; reduction or elimination of muffler and exhaust pipe discoloration due to exothermic chemical reactions. The present invention, in certain embodiments, allows for smaller substrates and thus smaller mufflers or canisters in certain systems. Because the substrate of the present invention improves thermal properties and does not absorb as much heat as some conventional substrates, the substrate of the present invention provides increased safety for systems using catalytic converters or particle filters. provide. Furthermore, the substrate of the present invention cools faster than many conventional substrates, resulting in increased safety. Certain embodiments of the present invention provide improved resistance to temperature changes so that even if sudden temperature changes occur, they will not crack, bend, or be damaged like some conventional substrates. Absent. In some embodiments, the substrate is easier to manufacture than conventional substrates (eg, an nSiRF-C wall flow substrate can be manufactured from a single piece of material rather than plugging a groove). This attribute saves cost as well as time.

  In other embodiments, nSiRF-C is not heavier than conventional post-processing equipment. This attribute is not only important for cars, but also extremely important in markets where weight is a factor (eg, small engines, motorcycles, personal ships, and high performance vehicles).

  In some embodiments, the substrates of the present invention exhibit lower back pressure than competing aftertreatment devices. This lower back pressure results in increased vehicle performance, increased horsepower, and increased fuel economy.

  Other embodiments of the invention include, for example, a method of catalyzing a reaction, a method of filtering a fluid, a method of preparing a catalyst substrate, a method of preparing a filtration substrate, a substrate prepared according to the above method, and further below. Directed to others as described in detail.

[Detailed Description of Embodiment of the Present Invention]
Overview The present invention is directed, in one embodiment, to a catalytic substrate suitable for use in many applications, including substrates in catalytic converters. Another aspect of the invention is a filtration substrate suitable for use in many applications, including substrates in particle filters such as diesel particle filters (DPF) or diesel particle traps (DPT). The present invention also provides an improved substrate for removing and / or eliminating pollutants from combustion engine exhaust. The catalyst substrate and filtration substrate provide improvements in removing contaminants from the exhaust gas in certain embodiments. Improvements include one or more of the following: rapid ignition period, increased PM depth filtration, low back pressure, low probability of clogging, and many locations in the exhaust system including the manifold or head itself Capacity, high probability of catalytic reaction, high conversion ratio of NO _x , HC and CO, faster burning of PM, minimization of catalyst material use, weight reduction of aftertreatment exhaust system, etc. It is not limited.

  Other embodiments of the present invention include catalytic converters, particle filters, diesel particle filters, diesel particle traps and the like. The present invention also provides methods for producing and preparing catalysts and filter substrates, catalytic converters, particle filters, catalyst mufflers and exhaust systems. Other embodiments of the present invention include pre-catalytic converters, post-catalytic converters, head catalytic converters and mani-catalytic converters, each of which includes a substrate of the present invention. Furthermore, the present invention is directed, in an alternative embodiment, to a substrate manufactured according to the methods described herein.

In another aspect, the invention includes a catalytic or filtration substrate that provides one or more of the following attributes: rapid ignition period, increased PM depth filtration, low back pressure, low probability of clogging. , Ability to be configured at many locations in the exhaust system, including the manifold or head itself, high probability of catalytic reaction, high conversion ratios of pollutants such as NO _x , HC and CO, faster PM Burnout, low amount of catalyst material required, quick ignition for cold start; low external wall temperature of substrate, etc.

  The use of the substrate, catalytic converter, particle filter or exhaust system of the present invention provides many advantages and improvements over the prior art. In some embodiments, these improved catalytic converters and / or particle filters remove and / or eliminate pollutants from the exhaust of combustion engines having many specific advantages, as described in more detail below. Can do. An improved exhaust system is likewise an additional aspect of the invention described herein. The improved exhaust system reduces the amount of pollutants emitted from the working engine.

  The invention is described in further detail below, including non-limiting embodiments and examples. The embodiments discussed herein are provided for illustrative purposes only. The present invention is not limited to these embodiments.

Catalytic Substrate The present invention comprises a non-woven sintered refractory fibrous ceramic (nSiRF-C) composite as described herein, which can be used in catalytic converters, particle filters and related equipment, or Consisting of or consisting essentially of them; optionally further directed to a catalyst substrate comprising an effective amount of catalyst such as a catalytic metal. Preferably the catalyst substrate comprises a catalyst. The nSiRF-C composite material can be shaped into a three-dimensional configuration suitable for use as described herein.

  The nSiRF-C composite is non-woven. In some embodiments, the nSiRF-C composite material is a material having a limited rigid three-dimensional shape. The fibers of the nSiRF-C composite material are not arranged in an organized pattern, but are arranged three-dimensionally in a random, unplanned or omnidirectional manner. In some embodiments, nSiRF-C is in the form of a matrix.

  nSiRF-C is a sintered composite material. In one embodiment, the sintered composite material is a sticky mass formed by heating without melting. However, methods for sintering ceramic materials are known in the art, and therefore the scope of the present invention is not necessarily limited to the specific embodiments and descriptions described herein. Sintering produces bonds without resin residues. In the context of the present invention, a sintered ceramic is a sticky mass of dispersed fibers formed by heating without melting.

  nSiRF-C is a refractory fibrous ceramic composite material. Certain embodiments of nSiRF-C are comprised of high-grade refractory fibers of various lengths and compositions as exemplified in the non-limiting embodiments herein.

  In one embodiment, the present invention is directed to a catalyst substrate suitable for use in many applications as described herein. Such substrates include many materials having one or more, preferably multiple, attributes as described herein. The substrate of the present invention is made from a nonwoven fiber ceramic composite made from fire resistant grade fibers. Such materials are disclosed in U.S. Patent No. 6,057,028, which is hereby incorporated by reference in its entirety. Other suitable materials are disclosed in US Pat.

  In one embodiment, the catalytic substrate of the present invention comprises, consists of, or consists essentially of an alumina reinforced thermal insulation (“AETB”) material or similar materials known to those skilled in the art. AETB materials are known in the art and are described more fully in Non-Patent Document 6 and Non-Patent Document 7, both of which are incorporated herein by reference.

  In another embodiment, the catalyst substrate comprises a ceramic tile, such as alumina reinforced insulation (AETB), with a reinforced uni-piece fibrous insulation (TUFI) and / or a reaction hardened glass (RCG) coating. Such materials are known in the art.

  Another suitable material is a fibrous refractory ceramic insulation (FRCI). In one embodiment, AETB is made from alumina boria silica (also known as alumina-boria-silica, aluminoborosilicate, and aluminoborosilicate) fibers, silica fibers, and alumina fibers. One commonly known application for AETB is as an external tile on the space shuttle that is ideal for shuttle atmospheric reentry. AETB has a high melting point, low thermal conductivity and low coefficient of thermal expansion, ability to withstand thermal and vibration shock, low density, and very high porosity and permeability. Thus, in a preferred embodiment, the catalyst substrate has a high melting point, low thermal conductivity, low coefficient of thermal expansion, ability to withstand thermal and vibration shock, low density, high porosity and high permeability.

In one embodiment, the first component of the AETB is an alumina fiber. In the preferred case of the present invention, the alumina (Al ₂ O ₃ or aluminum oxide (eg, SAFFIL)) is typically about 95 to about 97 wt% alumina and about 3 to about 5 wt% silica in commercial form. is there. In other embodiments, alumina having a lower purity (eg, 90%, 92% and 94% purity) is also useful. In other embodiments, alumina with higher purity is also useful. Alumina can also be produced by extrusion or spinning. First, a solution of precursor species is prepared. A slow, gradual polymerization process is initiated, for example, by manipulation of pH, whereby individual precursor molecules combine to form larger molecules. As this process proceeds, the average molecular weight / size increases, thereby increasing the viscosity of the solution over time. At a viscosity of about 10 mPa · S (centipoise), the solution becomes slightly tacky and the fibers can be drawn or spun. In this state, the fiber can also be extruded through the die. In some embodiments, the average fiber diameter is about 1-6 μm (microns), although larger diameter fibers and smaller diameter fibers are also suitable for the present invention. For example, the fiber diameter in other embodiments is in the range of 1-50 μm (microns), preferably 1-25 μm (microns), more preferably 1-10 μm (microns).

In one embodiment, the second component of AETB is silica fiber. In some embodiments, silica (SiO _2, for example Q- fibers or quartz fibers) is very amorphous silica which contains more than 99.5 wt% at low impurity levels. Low purity silica (eg, 90%, 95%, and 97%) is also useful in the present invention. In some embodiments, low density (eg, 2.1-2.2 g / cm ³ ), high heat resistance (1,600 ° C.), low thermal conductivity (about 0.1 W / m-K), and zero Amorphous silica with near thermal expansion is used.

In one embodiment, the third component of AETB is alumina boria silica fiber. In an embodiment, an alumina board rear silica fibers _{(3Al 2 O 3 · 2SiO 2} · B 2 O 3, for example, NEXTEL 312) is typically 62.5 weight percent alumina, 24.5 weight percent silica, and 13 % By weight of boria. Of course, the exact proportions of the components of alumina boria silica may be varied. Mainly alumina boria silica is an amorphous product, but it may contain crystalline mullite. Suitable alumina boria silica fibers and methods of making the same are described, for example, in US Pat. No. 6,057,096, the teachings of which are hereby incorporated by reference in their entirety.

  Other suitable materials for use as the substrate of the present invention include Orbital Ceramics Thermal Barrier (OCTB) available from Orbital Ceramics (Valencia, CA).

Other suitable materials for use as the nSiRF-C of the present invention include AETB-12 (about 20% Al ₂ O ₃ , about 12% NEXTEL® fiber (14% B ₂ O ₃ , 72% Al ₂ O ₃ , 14% SiO ₂ ) and about 68% SiO ₂ ), AETB-8 (about 20% Al ₂ O ₃ , about 12% NEXTEL® fibers (14% B ₂ O ₃ , 72% Al ₂ O ₃ , 14% SiO ₂ ) and 68% SiO ₂ composition), FRCI-12 (about 78 wt% silica (SiO ₂ ) and 22 wt% aluminoborosilicate (62% Al ₂ O ₃ , 24% SiO ₂ , 14% B ₂ O ₃ ) and FRCI-20 (about 78 wt% silica (SiO ₂ ) and about 22 wt% aluminoborosilicate (62% Al ₂ O) ₃ , 24% SiO ₂ , 14% B ₂ O ₃ )).

  In a preferred embodiment, the inorganic fiber component comprises or consists essentially of fibrous silica, alumina fiber, and aluminoborosilicate fiber. In this embodiment, the fibrous silica comprises about 50-90% (percent) of the inorganic fiber mixture, the alumina fiber comprises about 5-50% (percent) of the inorganic fiber, and the aluminoborosilicate fiber is the inorganic fiber mixture. About 10-25% percent. In certain embodiments, the fibers used to prepare the substrate of the present invention may have both a crystalline phase and a glass phase.

Other suitable fibers preferably include aluminum oxide in the range of about 55 to about 75% by weight, silicon oxide in the range of greater than 0 and less than about 45% by weight (preferably greater than 0 and less than 44% by weight), and Contains boron oxide (preferably about 1 to about 5% by weight) in the range of more than 0 and less than 25% by weight (calculated by the oxygen-based theoretical values of Al ₂ O ₃ , SiO ₂ , and B ₂ O _3, respectively) Aluminoborosilicate fiber). The aluminoborosilicate fibers are preferably at least 50% by weight of crystals, more preferably at least 75% by weight and most preferably about 100% by weight of crystals (so-called crystal fibers). Standard size aluminoborosilicates are commercially available, for example, as product codes “NEXTEL 312” and “NEXTEL 440” manufactured by 3M Company. In addition, suitable aluminoborosilicate fibers can be made, for example, as disclosed by US Pat.

  Further suitable fibers include aluminosilicate fibers, which are generally crystalline and range from about 67 to about 77% by weight (eg, 69, 71, 73 and 75% by weight) aluminum oxide and about 33%. Contains silicon oxide in the range of ˜about 23 wt% (eg 31, 29, 27 and 25 wt%). The standard size aluminosilicate fiber is commercially available, for example, as a product code “NEXTEL550” manufactured by 3M Company. In addition, suitable aluminosilicate fibers can be made, for example, as disclosed by US Pat. No. 6,053,077, the disclosure of which is incorporated herein by reference.

In another embodiment, the fibers used to prepare the substrate of the present invention are α-Al ₂ O ₃ with added Y ₂ O ₃ and ZrO ₂ and / or α-Al with added SiO _{2. 2} O ₃ (forms α-Al ₂ O ₃ / mullite).

  A variety of specific materials can be used to prepare the catalyst substrate. In one embodiment, the materials used to prepare the substrates of the present invention contain, consist of, or consist essentially of heat resistant silica fibers and heat resistant aluminum borosilicate fibers. In other embodiments, the materials used to prepare the catalyst substrate include heat resistant silica fibers, heat resistant grade alumina fibers, and a binder, preferably boron oxide or boron nitride powder. In other embodiments, the fibers are high grade.

  In another embodiment, the substrate comprises aluminosilicate and silica fibers having a weight ratio in the range of about 19: 1 to 1:19 and about 0.5-30% boron oxide based on the total weight of the fibers. Includes essentially heat-resistant composite material. Alternatively, the weight ratio of aluminosilicate fiber to silica fiber is 16: 1, 14: 1, 12: 1, 10: 1, 8: 1, 6: 1, 4: 1, 2: 1, 1: 1, Selected from 1: 2, 1: 4, 1: 6, 1: 8, 1:10, 1:12, 1:14, and 1:16. In other embodiments, the boron oxide is present at about 5%, 10%, 15%, 20%, 25%, or 30%. In a further embodiment, the boron oxide and aluminosilicate fibers are present in the form of aluminoborosilicate fibers. In a further embodiment, the catalyst substrate contains an nSiRF-C composite (wherein the ratio of aluminosilicate fibers to silica fibers ranges from 1: 9 to 2: 3 and the boron oxide content is About 1-6% of the fiber weight).

In another embodiment, suitable fibers for preparing the substrate of the present invention include: NEXTEL® ceramic fiber 312, NEXTEL® ceramic fiber 440, NEXTEL® ceramic fiber 550, NEXTEL ( 3M heat-resistant fibers, such as registered ceramic fiber 610 and NEXTEL® ceramic fiber 720 are included. Composite grade fibers Nextel® fibers 610, 650, and 720 have a crystal structure based on more refined α-Al ₂ O ₃ and do not contain any glass phase. This allows the fiber to maintain strength at higher temperatures than industrial fiber. Nextel® fibers 610 essentially comprise a single phase composite material of α-Al ₂ O ₃ . Nextel® fibers 610 have the lowest holding strength at certain temperatures, even though they start at the highest strength at room temperature. Nextel® fiber 650, which is α-Al ₂ O _{3 to} which Y ₂ O ₃ and ZrO ₂ are added, and Nextel® fiber 720, which is α-Al ₂ O ₃ to which SiO ₂ is added. Both have higher holding strength and lower creep at certain temperatures.

In another preferred embodiment, nSiRF-C is made from or includes (or consists of) ceramic fibers containing Al ₂ O ₃ , SiO ₂ , and B ₂ O ₃ having the following properties: 1) Melting point, about 1,600 ° C. to about 2,000 ° C., preferably about 1,800 ° C .; 2) Density, about 2 to about 4 g / cc, preferably About 2.7 to about 3 g / cc, 3) refractive index, about 1.5 to about 1.8, more preferably selected from 1.56, 1.60, 1.61, 1.67, and 1.74 4) Filament tensile strength (metric, 25.4 mm), about 100 to about 3,500 MPa, more preferably about 150 to about 200 MPa or about 2,000 to about 3,000 MPa, or 150, 190, 193, 2,100, Is selected from 3,100 MPa, 5) thermal expansion (100-1100 ° C.), about 2 to about 10, preferably about 3 to about 9, more preferably 3, 4, 5.3, 6, and 8 And 6) a surface area of less than about 0.4 m ² / g, more preferably less than about 0.2 m ² / g. In other embodiments, the crystalline phase of the fiber is mullite and amorphous, substantially amorphous γ-Al ₂ O ₃ , or amorphous SiO ₂ . In still other embodiments, the dielectric constant of fibers suitable for use in preparing a substrate according to the present invention is from about 5 to about 9 (at 9.375 GHz), or preferably 5.2, 5.4. Selected from the group consisting of 5.6, 5.7, 5.8, 6, 7, 8, and 9.

  In certain embodiments, the substrate of the present invention is “shot-free” meaning that it is substantially free of particulate ceramic (so-called crystalline ceramic, glass, or glass-ceramic) in the fiber manufacturing process. is there.

  In some embodiments, the nSiRF C composite is “inflexible”. In one embodiment, an inflexible substrate is 1, 2, 3, 4, 5, 6, 7 without breaking, cracking, or permanently deforming or deforming (relative to the bending point). , 8, 9, 10, 15, 20, or 25 ° or more.

  The fiber diameter used in different embodiments of the invention can vary. In some embodiments, the average diameter is about 1 to about 50 μm (microns), preferably 1 to about 20 μm (microns). In another embodiment, the average diameter is about 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 μm (microns). In another embodiment, the average fiber diameter of the aluminia boria silica fibers is about 10 to about 12 μm (microns).

  In another embodiment, the catalyst substrate of the present invention further contains a binder such as boron nitride. In another embodiment of the present invention, boron nitride is applied in place of alumina borosilica fibers when no alumina borosilica fibers are used. That is, in some embodiments, the substrate comprises (or consists of, consists essentially of, or is made of) silica fiber, alumina fiber, and boron nitride as much as the weight percents described above. ) In a further embodiment, the substrate comprises silica fibers, alumina fibers, and a boron binder. In some embodiments, each of these may contain small amounts of other materials such as organic binders, inorganic binders and some fibrous or non-fibrous impurities. In another embodiment, the substrate does not include an organic binder. In yet another example, the binder used to produce nSiRF-C is materially altered during the fabrication process, as is known in the art.

  Additional materials suitable for use in preparing the substrate of the present invention are low density fused fibers prepared from amorphous silica and / or alumina fibers having 2-12% boron nitride based on fiber weight. A ceramic composite material is described in US Pat. In another embodiment, a thickener is added. Suitable thickeners are known in the art.

  In another embodiment, the ceramic fibers used to prepare nSiRF-C are greater than about 700 MPa (100,000 psi), preferably greater than about 1,200 MPa (200,000 psi), more preferably about 1 , 800 MPa (300,000 psi), and most preferably greater than about 2,100 MPa (350,000 psi).

  In another embodiment, a dispersant is added. Suitable dispersants are known in the art.

  In other embodiments, the catalyst substrate is treated, altered, modified, and / or in one or more aspects as described herein and / or as known in the art. Strengthened.

  In still other embodiments, there are small amounts of impurities from various sources. In these cases, the impurities do not substantially affect nSiRF-C and / or its attributes.

  The substrate of the present invention does not include a NEXTEL® woven fabric or mat.

Catalyst In another aspect, the invention is directed to a substrate as described above comprising a catalyst. Any number of catalysts are used with the substrate to form the catalyst substrate. The catalyst can be coated on the surface of the substrate. That is, in one embodiment, the catalyst is adsorbed on the surface of the catalyst substrate (eg, the groove wall). The catalyst is also present inside the core of the substrate and is attached to the individual fibers of the substrate. In some embodiments, the present invention may function at the same or better levels as compared to current technology, but requires a smaller amount of catalyst.

  In another embodiment, the catalyst is deposited only on the groove wall surface and not within the groove wall. In another embodiment, the catalyst is deposited on the inlet groove wall, on the outlet groove wall, in the wall, or a combination thereof. In yet another embodiment, the primary catalyst is aligned, coated or penetrated at the start or proximal portion of the groove wall; the secondary catalyst is aligned, coated or penetrated at the intermediate portion of the groove wall. And a tertiary catalyst in the end section of the groove wall.

  In one embodiment, the catalyst substrate of the present invention preferably contains a catalytic metal. For other metals, the catalyst substrate does not contain a catalyst metal. However, under certain conditions, the substrate can catalyze an appropriate reaction without the need for a separate catalytic metal, for example, in certain embodiments, a washcoat as described below can function as a catalyst.

Any catalyst applicable to the substrate can be used. Such catalysts include, but are not limited to, platinum, palladium (eg, palladium oxide), rhodium, derivatives thereof such as oxides, and mixtures thereof. Further, the catalyst is not limited to a noble metal, a combination of noble metals, or an oxidation catalyst. Other suitable catalysts include chromium, nickel, rhenium, ruthenium, silver, osmium, iridium, platinum and gold, iridium, derivatives thereof and mixtures thereof. Other suitable catalysts include binary oxides of palladium and rare earth metals, as disclosed in US Pat. These binary oxide is obtained by a solid phase reaction between palladium oxide and rare earth metal oxides, _{e.g., Sm 4 PdO 7, Nd 4} PdO 7, Pr 4 PdO 7 or La4PdO ₇ can be manufactured. Other catalysts that can be used in the present invention include those disclosed in Patent Document 15 (assigned to Mazda Motor Corporation). Other suitable catalysts include non-metallic catalysts, organic catalysts, base metal catalysts, precious metal catalysts and noble metal catalysts.

  Other suitable catalysts are disclosed in U.S. Patent No. 6,057,034 (assigned by Johnson Matthey Public Limited Company). A catalyst containing no noble metal can be used in the present invention. Such a catalyst is found in US Pat.

Another suitable platinum catalyst developed by Engelhard is a 5: 1 ratio of Pt / Rh (applied in an amount of about 0.18-5.30 kg / m ³ (about 5-150 g / ft ³ )) and MgO ( 1.06 to 52.98 kg / m ³ (applied in an amount of ^{30 to} 1,500 g / ft ³ ).

In other embodiments, vanadium and its derivatives (eg, V ₂ O ₅ ) are useful catalysts, particularly for diesel particulate filters. Such catalysts have been used in commercial diesel particle filters.

Catalysts have been developed that utilize vanadium compounds other than V ₂ O ₅ , such as silver or copper vanadate. An example of a copper vanadate base metal catalyst was developed by Heraeus (Strutz 1989). The catalyst can be prepared by doping and calcining copper vanadate Cu ₃ V ₂ O ₈ with potassium carbonate at a molar ratio of Cu: V: K of about 3: 2: 0.13. The catalyst load was 10 to 80 g / m ² (filtration surface area). Another suitable catalyst is Cu / ZSM5, which can be used as a DeNox catalyst.

  Noble metals such as platinum, palladium and rhodium are the most common and preferred, but other catalysts known in the art can also be used. These three precious metals have been known as excellent, highly efficient catalysts associated with internal combustion engine emissions. In catalytic converters over 25 years, there was actually no significant alternative to this triplet. However, there are thousands of combinations of these catalysts designed by the original equipment manufacturer, vehicle, vehicle load, environmental regulations, engine, transmission, etc. Various combinations and formulations of catalysts are used throughout the truck and automobile manufacturing industry. The catalyst substrate according to the present invention comprises any one or more combinations of these catalysts. Many combinations are contrived proprietary materials. Manufacturers such as Ford, GM and Toyota have their own catalyst formulations for each vehicle due to various vehicle weight and engine performance requirements. Manufacturers also have different catalyst formulations for the same vehicle, depending on where the vehicle is sold or licensed (eg, Canada, USA, California, Mexico). In general, these formulations may vary 2-3 times per vehicle per model year due to strict government regulations. For these reasons, most manufacturers deal with the application of the catalyst coating itself.

  In a further embodiment, the catalyst substrate comprises nSiRF C and a catalyst used in a commercial catalyst environment.

  In one aspect, once the substrate has been shaped to its final dimensions, and the washcoat has been applied and cured, known techniques and methods (eg, US Pat. One or more catalysts are applied using a method) of applying a palladium-platinum-based catalyst as disclosed in)), which is incorporated herein in its entirety.

  In one embodiment, the catalyst is in an amount sufficient for catalysis to occur effectively. For example, a sufficient amount, in one embodiment, interacts with as many exhausts as possible, such as 80%, 85%, 90%, 95%, 97%, 98% and 99%, and so on. Refers to the amount of catalyst (eg noble metal) in the exhaust path sufficient to react.

  In one embodiment, the catalyst is deposited on or impregnated in the washcoat, preferably as individual crystals. In this embodiment, the catalyst is not applied as a veneer-like coating on the washcoat (such as paint on the wall). When the catalyst is impregnated into the washcoat, they are applied such that the final product is partially or substantially individual colonies of crystals. This can be visualized as a salt crystal on a pretzel. It is preferred that sufficient spacing is provided between the catalysts. At the same time, there should be sufficient noble metal in the fluid path (eg, exhaust path) at the optimum catalytically active operating temperature (ie, ignition) and the physics enabled by vehicle and engine functionality and design. Must fit within the physical constraints (ie space).

  The manufacturing goal is to maximize the contaminants removed while minimizing the amount of catalyst required on the substrate. Each vehicle produces a different amount of contaminant, as such, in some embodiments, the substrate is tailored to address that level of contaminant and minimize the amount of precious metal.

  In another embodiment, catalyst addition to the catalyst substrate can occur during the slurry process when the substrate is manufactured, or it can occur after a machining process (below). In this case, the catalyst is mixed with the fiber slurry prior to any heating process.

  Single and many catalyst formulations can be applied to a single substrate, or because of the small size of the filter relative to existing catalytic converters and exhaust systems, multi-substrate configurations are possible. Thus, the catalyst substrate of the present invention in one embodiment comprises, consists of or consists essentially of one or more zones, where each zone has a different catalyst. Alternatively, one or more zones cannot be catalyzed. For example, the catalyst substrate of the present invention can include an oxidation catalyst in one zone containing the front surface of the substrate and a reduction catalyst in another zone containing the back surface.

  If the substrate is to be used in a flow-through configuration, it is preferred, but not required, that the catalyst or the majority of the catalyst be present along the surface of the groove. When the substrate is machined to a wall flow configuration, the gas is intended to travel through all of the substrate, but not exactly passing through, so the catalyst is evenly distributed throughout the substrate. Preferably it is done.

  For example, the substrate of the present invention can be used in a catalyzed diesel particulate filter (CDPF). CDPF utilizes a catalyst that is deposited directly on the substrate. Noble metal and base metal catalysts (eg, platinum, silver, copper, vanadium, iron, molybdenum, manganese, chromium, nickel, their derivatives (eg, oxides), etc.) can be used together. Depending on the type of filter, the catalyst can be impregnated directly into the medium or an intermediate washcoat layer can be used. CDPF may utilize an exhaust temperature of about 325-420 ° C. for regeneration, depending on engine technology (PM exhaust) and fuel quality (sulfur content).

  Platinum is one of the most active and most commonly used noble metal catalysts, but palladium, rhodium or ruthenium catalysts are also usually mixtures and are suitable for use in the present invention. Common non-platinum group metals used in catalytic converters include vanadium, magnesium, calcium, strontium, barium, copper and silver. In one embodiment, platinum is a preferred catalyst for use with a diesel engine. In another embodiment, palladium and rhodium suitable for use with a gasoline engine.

  Catalysts are generally very expensive. Therefore, it is desirable to achieve the maximum reduction in contamination with the minimum amount of catalyst used. Two common catalysts, platinum and palladium, are both expensive noble metals. A substrate having porous permeability with a large surface area in which the catalyst remains as uniformly distributed crystals or layers makes it possible to achieve that purpose. An advantage of the present invention is that less catalyst is required compared to conventional substrates.

Typical platinum content in filters used for off-road engines throughout the 1990s was 1,236-1,766 g / m ³ (35-50 g / ft ³ ). These filters incorporated in relatively high pollution engines required a minimum temperature of about 400 ° C. for regeneration. Later, it was found that when applied to much cleaner city buses and other highway vehicle engines, the catalyst filter could be regenerated at a much lower temperature. However, higher platinum levels were required to support low temperature regeneration. Filters used for clean engine low temperature applications generally have platinum amounts of 1,766 to 2,648 g / m ³ (50 to 75 g / ft ³ ).

In one embodiment, the catalyst substrate is about 35.32 to about 3,532 g / m ³ (about 1 to about 100 g / ft ³ ), about 35.32 to about 1,766 g / m ³ (about 1 to about 50 g / ft ³ ), about 35.32 to about 1,236 g / m ³ (about 1 to about 30 g / ft ³ ), or about 353.2 to about 1,413 g / m ³ (about 10 to about 40 g / ft ^3). ) In the amount of catalyst.

In another embodiment, the catalyst substrate, preferably nSiRF-C (eg, AETB, OCTB, and FRCI) is used in an amount of about 1,236 g / m ³ (about 30 g / ft ³ ) in a ratio of about 5: 1. Contains platinum and rhodium catalysts.

Filtration substrate The present invention is directed to a catalyst substrate comprising a non-woven sintered refractory fibrous ceramic (nSiRF-C) composite material as described herein that can be used in particle filters and related equipment. It is done. The filtration substrate is made up to a specific shape, design, size and configuration that is useful for filtration, particularly for filtering particulate matter. Filter substrates are particularly useful for filtering particulate matter under extreme conditions (temperature, pressure, etc.), for example, for filtering an exhaust gas stream. The filtration substrate can be used for additional applications where filtration of small particulate matter is required.

  In one embodiment, the filtration substrate comprises, consists of, or consists essentially of nSiRF-C composite materials as described above for the catalyst substrate. The filtration substrate does not contain a catalyst. All material modifications, embodiments and examples suitable for use as a catalyst substrate are equally suitable for the filtration substrate of the present invention.

  The filtration substrate is shaped into a configuration suitable for use as described herein, particularly for use in particle traps and diesel particle filters, such as diesel particle traps.

  In one embodiment, the filtration substrate of the present invention is an alumina reinforced thermal insulation (“AETB”) material or similar material known to those skilled in the art. AETB is made from alumina boria silica (also known as alumina-boria-silica, aluminoborosilicate, and aluminoborosilicate) fibers, silica fibers, and alumina fibers. One generally known application for AETB is as an external tile on the space shuttle, which is ideal for shuttle reentry. The attributes that create a unique and desirable AETB for the space industry are also selected in organic combustion technology. AETB has a high melting point, low thermal conductivity and low coefficient of thermal expansion, ability to withstand thermal and vibration shock, low density, and very high porosity and permeability.

  The filtration substrate of the present invention is optionally treated with one or more chemical additives.

  In another embodiment, the present invention is directed to a diesel particle trap comprising a filter as described herein without any catalyst applied to the filter.

In another embodiment, the present invention is directed to a diesel particle trap comprising a filter as described herein in combination with a CRT® diesel particle trap (NO _x , HC adsorbent).

  In another embodiment, the present invention is directed to a diesel particle trap comprising a filter as described herein in combination with an SCR.

  In another embodiment, the filter substrate includes a plurality of grooves as described in further detail below. Further, the filtration substrate may be modified, altered, and / or enhanced in one or more aspects as described herein and / or as is known in the art.

Catalyst and Filtration Substrate Attributes The present invention has one or more, preferably at least 3, 4, 5, 6, 7, 8, 9 or 10 which are more beneficial than conventional catalyst or filtration substrates. It has the attribute of.

Suitability for use The present invention is directed, in one embodiment, to a catalytic or filtration substrate comprising nSiRF-C and a catalyst suitable for use in a catalytic converter. The substrate is suitable for use in any number of catalytic converters, filtration devices and applications.

  For example, the catalyst substrate and filtration substrate of the present invention are suitable for use in any application commonly used for prior art substrates. Suitable uses include the use of the substrate of the present invention in an exhaust system, the exhaust system 1) mobile on-road engines, equipment and vehicles (automobiles and light trucks; for public roads) Motorcycles and street motorcycles, three-wheeled motorcycles (eg, electric tricycles, auto-rich shows), electric tricycles (including large public road engines such as trucks and buses), 2) mobile off-road engines, equipment and vehicles (compression) Combustion engine (for farm, construction, mining, etc.); Small spark combustion engine (lawn mower, leaf blower, chainsaw, etc.); Large spark combustion engine (forklift, generator, etc.); Marine diesel engine (commercial use) Ships, recreational diesel, etc.); marine spark combustion engines (boats, personal sailing vessels, etc.); recreational vehicles ( Snowboard building, dirt bike, all-terrain beagle, etc.); locomotive; aircraft (including airplanes, ground support equipment, etc.)), 3) stationary pollution sources (including hundreds of pollution sources such as power plants, refineries and manufacturing plants) ) Any exhaust system, but not limited thereto.

  In another embodiment, if the substrate as described herein is part of a catalytic converter, the emission criteria of any one of 1990, 2007 and 2010 as the vehicle is defined by EPA. When it functions so as to satisfy the above, the catalyst base material of the present invention is suitable for use in a specific vehicle.

In another embodiment, the catalyst substrate catalyzes the reaction of contaminants to non-pollutants at a high level. For example, the conversion of pollutants to non-pollutants is catalyzed with an efficiency greater than 50%. In another embodiment, the conversion of pollutants to non-pollutants is catalyzed with an efficiency greater than 60%. In still other embodiments, the conversion is 70%, 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, and 99.9. Selected from the group consisting of%. In some embodiments, the conversion rate represents the total conversion of non-particulate contaminants. In another embodiment, the conversion rate is a conversion of certain non-particulate contaminants (eg, conversion of NOx to N ₂ , conversion of CO to CO ₂ , or conversion of HCs to CO ₂ and H ₂ O). Show. In another embodiment, the conversion rate indicates the percentage of particulate matter removed from the exhaust gas.

  In another embodiment, the catalytic substrate of the present invention is suitable for use in a particular application if it passes a preferred test as defined by some OEMs such as the US Federal Test Protocol 75 (US FTP75). Yes. Such tests are known in the art (see, eg, Non-Patent Document 8, which is incorporated herein by reference in its entirety). Further, the use of products containing the substrate included herein should be approved by the EPA and / or state / department agency as back-cat or DPT in retrofit applications. .

Surface area The available surface area of a substrate is an important attribute of a filtration substrate or a catalyst substrate. One characteristic of a suitable substrate for a catalytic converter is that it has a high geometric surface area (GSA). A high GSA allows for maximum response probability.

  Large open front surface area (OFA) allows more gas to pass through without blocking the flow and creating back pressure. The pre-open surface area (OFA) is defined as the portion of the total substrate cross-sectional area (ie, the cross-sectional area of the filter inlet groove) that is available for gas flow. It is typically expressed in terms of the total substrate cross section.

  One attribute of the substrate of the present invention is its high surface area or high GSA. The surface area of the substrate is an important attribute for catalyst applications. The surface area is the total amount of surface that must pass through as exhaust exhaust moves through the exhaust filter. The surface area increase translates into a surface increase where chemical reactions occur between contaminants and the catalyst and thermal processes, making the catalytic converter process faster and more efficient. Speed and efficiency cause little or no clogging that can cause exhaust system failures. Furthermore, increasing the surface area of the substrate of certain embodiments also includes increasing filtration efficiency and / or capacity.

  The geometric surface area is the total surface area on which noble metals can be impregnated on 1 cubic inch. A substrate having a high total surface area is preferred. Certain embodiments of the present invention have a very high geometric surface area that can be impregnated with a catalyst compared to conventional substrates such as cordierite and SiC.

  Total wall volume is the total amount of wall volume present in a 1 cubic inch design substrate. The total wall volume is calculated and summed as each wall surface area multiplied by each thickness. A substrate having a low total wall volume is preferred. In certain embodiments, the total wall volume of the substrate of the present invention is lower than that of conventional substrate materials such as cordierite and SiC.

In some embodiments, the total wall volume of the catalyst substrate is about 0.5 to about 0.1, about 0.4 to about 0.2, or about 0.3 in ³ / in ³ (cubic inch / cubic inch). ). In a preferred embodiment, the total wall volume substrate is about 0.25 to about 0.28, more preferably about 0.27, more preferably about 0.272 in ³ / in ³ .

  Because of the lower total wall volume of the present invention in certain embodiments, less catalyst, such as palladium, than a similarly sized cordierite is required to perform catalysis using the present invention.

Porosity and permeability Pore attributes also affect the mechanical and thermal properties of the substrate. Exchange conditions can exist between porosity and mechanical strength: pore sizes are smaller and low porosity substrates are stronger than those with higher porosity for certain conventional substrates. Thermal properties of both specific heat capacity and thermal conductivity can be reduced with increasing porosity in certain materials (Yuuki 2003).

  Primary wall flow monoliths introduced in the late 1980s had grooves with a diameter of 35 μm. To maximize filtration efficiency, the grooves were smaller and were typically made in the 10-15 μm range for filters used in the 1990s. In the development of new materials, filter manufacturers distinguish their target pore attributes mainly considering the catalyst system to be applied (Non-Patent Document 9 and Non-Patent Document 10). Applications can be classified as follows:

  Non-catalytic filters, such as those used in fuel additive regeneration systems: the main issue is the ability to retain high soot. Some conventional filters have a porosity that is about 40-45% and the pores are 10-20 μm.

Catalytic filters, such as those in passive regeneration systems, require more porosity and possibly larger pore sizes (often very small washcoats) to allow coating with increasingly more complex catalyst systems. In contrast to simple catalysts used in the 1990s with or without material). The substrate should have an acceptable low pressure drop after being coated with the catalyst / washcoat system in an amount of about 50 g / dm ³ . Certain prior art filters have a porosity in the range of about 45-55%. Additional heaters can also be applied.

Filter / NO _x adsorber devices, such as DPNR systems or CRTs (continuous regeneration traps), incorporate NO _x storage / reduction systems and require high washcoat amounts, possibly above 100 g / dm ³ . Certain prior art substrates have a porosity of approximately 60% (substrates with a porosity of 65% have been reported and mechanical strength is a major limitation in increasing porosity (11).

  Another attribute of certain embodiments of the catalyst substrate or filtration substrate of the present invention is its high porosity. In certain embodiments, the porosity of the substrate of the present invention is from about 60%, 70%, 80% or 90%. In other embodiments, the substrate has a porosity of about 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% (pore space relative to the solid substrate). Expressed as a percentage).

  In one embodiment, the porosity of an exemplary embodiment of the invention is about 97.26%. By comparison, cordierite is about 18-42%. In this embodiment, the material of the present invention has only about 2.74% material to block the exhaust gas flow. This fine woven material actively captures the particles and burns them out very effectively. Due to trapping of the particles in the depth filtration mode and not only along the groove walls, a large amount of PM increase does not occur under conditions where the regeneration time is longer than the PM increase time. High porosity translates into better and more effective interactions between contaminants and catalytic or non-catalytic substrate surfaces. At the same time, the gas flow augmentation can be released laterally as well as along the intended gas flow direction.

  With reference to FIGS. 22a and 22b, an exemplary substrate 2200, substrate 2205 of the present invention is shown. The substrate 2200 and the substrate 2205 are approximately 97% porous substrates. Compared to the cordierite of FIGS. 2a and 2b and the silicon carbide sample of FIG. 3, they are all at substantially the same scale, and the substrate 1200 and substrate 1205 are more porous and less dense. In FIG. 22b, particulate matter PM-10 2210 and particulate matter PM-2.5 2225 are illustrated on a constant scale. Compared to the cordierite sample 205 illustrated in FIG. 2 b, the particulate material PM-10 2210 and the particulate material PM-2.5 2225 can easily penetrate the fibers of the substrate 2205. Compared with the silicon carbide 300 of FIG. 3, the density of silicon carbide is about 30 to 50 times that of the base material 2200 and the base material 2205.

Higher porosity in certain embodiments of the present invention provides a larger surface area and lower back pressure. As a result, the present invention is more efficient for NO _x reduction, hydrocarbon and CO oxidation, and particulate trapping.

  Pore properties such as volume percent porosity, size distribution, structure and interconnectivity determine the monolithic ability to filter particles. Furthermore, if gas molecules can diffuse into the porous substrate, the probability of catalysis increases dramatically. Along with the cell structure, the porous nature also affects the flow resistance and pressure drop of the monolith against flow. Some attributes desired for high filtration efficiency (eg low porosity and small pore size) are opposite to those required for low pressure drop. Others, such as good hole interconnectivity and the absence of closed “dead end” holes, are desirable for both low pressure drop and high efficiency. The substrate of the present invention in another embodiment provides both high filtration efficiency and low pressure drop.

Emissivity and thermal conductivity Another characteristic of substrates used in catalytic converters and particle filters is emissivity. Emissivity is the rate at which release occurs as a tendency to release heat; a comparison of the ease of release or as heat from the surface of the heating element.

  Ideal substrates are (1) the fastest trend towards high conversion efficiency; (2) safest from heat damage (eg due to thermal shock or due to high temperature melting / cracking of the substrate); (3) minimal Use an amount of auxiliary energy; and (4) take into account the temperature at which it is cheap to produce. Increasing temperature requires additional energy and cost. In addition, a certain amount of energy source is conducted, taken in or carried away by thermal conductivity.

  Emissivity is the ratio of reflectivity having a value between 0 and 1, with 1 being perfect reflection. The substrates used for catalytic converters and particle filters have different emissivity values. High emissivity minimizes heat transfer from the system to the catalyst substrate, thereby heating the air inside the catalytic converter or particle filter more quickly. The emissivity is a measured value of the thermal reflectance characteristics of the material, and a high value is desirable.

  In certain embodiments, the substrate of the present invention preferably has an emissivity of about 0.8 to 1.0. In another embodiment, the emissivity of the substrate of the present invention is about 0.82, 0.84, 0.86, 0.88, and 0.9. Further suitable values for the emissivity of the substrate of the present invention include 0.81, 0.83, 0.85, 0.87, and 0.89. In other embodiments, the emissivity is about 0.9, 0.92, 0.94, 0.96, or 0.98. Since the substrate material itself retains little heat, the gaseous material in the porous can be heated very quickly with thermal reflectivity. This results in a quicker ignition and the temperature of the substrate outer surface hardly increases.

  If the facing is following a unit temperature gradient, the thermal conductivity of the material is the amount of heat that passes through the unit area of the plate per unit time (eg, a 1 ° C. temperature difference through a unit thickness). Thermal conductivity has thickness (meter) and converted energy per kelvin (watts) as units (W / m-K). In a preferred embodiment, the substrate of the present invention has a low thermal conductivity. For example, in one embodiment, the thermal conductivity of the substrate of the present invention is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8. Or lower than 0.9. In another embodiment, the substrate has a thermal conductivity of about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, Or lower than 0.09. In another embodiment, the substrate of the present invention has a thermal conductivity of about 0.1 to about 0.01, about 0.2 to about 0.02, about 0.3 to about 0.03, about 0.0. 4 to about 0.04, about 0.5 to about 0.05, about 0.6 to about 0.06, about 0.7 to about 0.07, about 0.8 to about 0.08, or about 0 .9 to about 0.09. In another embodiment, the thermal conductivity of the present invention is about 0.0604 W / m-K.

  In comparison, cordierite samples are about 1.3-1.8 W / m-K. These results show that, as an example of a specific embodiment, if 1,000 watts of thermal energy is lost from a given volume of cordierite material, only 33 watts are lost from the same volume of the inventive material. Therefore, the material of the present invention has a thermal conductivity 30 times greater than cordierite.

  In still other embodiments, the substrate preparation method further comprises preparing a catalyst substrate or a filtration substrate further comprising an emissivity enhancer, wherein the method is applied to the substrate, preferably nSiRF-C. More preferably, including applying a radiation enhancer to the AETB, OCTB or FRCI material. Other preferred substrates include any of the specific substrates disclosed herein. In a further embodiment, the catalyst substrate further comprises an emissivity enhancer and a catalyst selected from the group consisting of palladium, platinum, rhodium, their derivatives and mixtures thereof. Other physical and chemical modifications as described herein may be applied to such embodiments. Emissivity enhancers are known in the art.

Thermal Attributes Substrates that exhibit a low coefficient of thermal expansion can tolerate rapid changes in temperature without significant expansion or contraction. A suitable coefficient of thermal expansion also causes the substrate to expand with the same rate of heat as the surrounding protective mat and canister.

  For example, if the temperature rises to a high value during occasional fuel combustion, it is also preferred that the substrate material withstand a wide range of temperatures so as not to melt the catalytic converter or particle filter. Further, if the substrate material can withstand high temperatures, the catalytic converter or filter can be placed closer to the engine.

  Related properties include low thermal mass and heat capacity. A material having a low thermal mass and heat capacity reduces the heat energy wasted in raising the temperature of the catalyst substrate. As the catalyst substrate is heated rapidly, the thermal energy generated by more exhaust gas is used to trigger ignition of the catalyst components.

  Thermal conductivity is the ability of a substance to conduct heat as a result of molecular motion. More specifically, thermal conductivity is also a measure of the amount of heat that passes through a unit area of a plate of uniform thickness in unit time when the opposite surfaces differ in temperature by 1 ° C. The more the material conducts heat, the more energy is needed to overcome losses and achieve the required temperature. Preferably the material reflects rather than conducts heat. Lower thermal conductivity values are preferred, where more thermal energy is utilized in the pore space and is not lost by absorption by the substrate. The chemistry of the different materials determines the level of thermal conductivity. In addition, since temperature loss has a negative effect on reactivity, the thermal conductivity of the filter medium is a significant effect on the efficiency of the exhaust exhaust filter. Low thermal conductivity is preferred because much of the generated thermal energy is reflected by the particles and remains in the pore space. In other words, the lower the thermal conductivity, the lower the heat loss. Lower heat loss translates to the lower energy and higher energy efficiency needed to achieve the desired temperature range for the catalytic converter.

  Specific heat is the heat (calories) required to raise the temperature of a gram of material by 1 ° C. A substrate with a high specific heat reflects, for example, ambient heat from exhaust or auxiliary sources to the pore space, where the combustion or catalytic reduction and oxidation processes require heat. For example, under extreme conditions, such as the Arctic, it takes longer to heat the low specific heat filter and cool the heat filter, increasing the chance of external heat damage. Low specific heat is preferred in order to achieve operating temperatures more quickly with low energy.

  In certain embodiments, the substrates of the present invention have many favorable thermal attributes. Preferably the material is such that heating of the air in the pore space occurs preferentially compared to heating of the substrate. Preferably, the substrate of the present invention has a high melting point, and in certain embodiments has a higher melting point than conventional substrates. A high melting point is preferred due in part to extreme temperatures to which the catalyst or filtration substrate is exposed.

  In a preferred embodiment, the substrate of the present invention preferably has a high melting point. In one embodiment, the melting point is greater than about 1,500 degrees (Fahrenheit). In another embodiment, the melting point is greater than about 2,000 degrees (Fahrenheit). In another embodiment, the melting point is greater than about 2500 degrees (Fahrenheit). In a further embodiment, the substrate has a melting point of about 2,000 to about 4,000 degrees Fahrenheit. In a further embodiment, the melting point of the substrate is from about 3,000 to about 4,000 degrees (Fahrenheit). Other suitable melting point ranges are about 3,000 to about 3,100 degrees Fahrenheit, about 3,100 to about 3,200 degrees Fahrenheit, about 3,200 to about 3,300 degrees Fahrenheit About 3,300 to about 3,400 degrees (Fahrenheit), about 3,400 to about 3,500 degrees (Fahrenheit), about 3,500 to about 3,600 degrees (Fahrenheit), about 3,600 to about 3 , 700 degrees (Fahrenheit), about 3,700 to about 3,800 degrees (Fahrenheit), about 3,800 to about 3,900 degrees (Fahrenheit) and about 3,900 to about 4,000 degrees Fahrenheit . In another preferred embodiment, the substrate has a melting point of about 3,632 degrees (Fahrenheit).

  In one embodiment of the present invention, the substrate has a melting point of about 3,632 degrees Fahrenheit. For example, if the vehicle is placed below the freezing temperature, a blow of 1,500 degrees Fahrenheit will not thermally decompose or break the substrate. Similarly, certain embodiments of the substrate do not overheat and decompose. Certain samples of cordierite have a melting point of about 1,400 ° C.

  The specific heat of an exemplary embodiment of the present invention is about 640 J / kg-K (joules / kilogram-kelvin). The cordierite sample is about 750 J / kg-K. Even though cordierite has a higher specific heat, the cordierite filter has a larger mass due to heating. The result is that more heat is needed to achieve operating temperatures that make cordierite less efficient.

  The temperature limit for multiple use is the maximum temperature at which the substrate can be run several times without significant degradation. The higher the temperature at which the substrate can continue to operate without micro-breaking or crushing, the less chance of substrate breakage or cracking over time. This means that the substrate is more durable over a wider temperature range. Higher multiple use temperature limits are preferred. Suitable multiple use temperature limits for certain embodiments of the catalyst substrate or filtration substrate of the present invention are about 2,000 ° C, 2,100 ° C, 2,200 ° C, 2,300 ° C, 2,400 ° C. , 2500 ° C, 2,600 ° C, 2,700 ° C, 2,800 ° C, 2,900 ° C, 3,000 ° C, and 3100 ° C.

  The multiple use temperature limit of the exemplary embodiment of the present invention is 2,980 ° C. The cordierite sample is about 1400 ° C. Embodiments of the invention can withstand more than twice the temperature of cordierite before failure. This allows the material to function in a wider range of exhaust environments.

  The coefficient of thermal expansion increases with respect to the original length, area or volume of the body length (linear coefficient), area (square) or volume for a given temperature rise (usually 0 to 1 ° C.) This is the ratio. These three factors are in a ratio of approximately 1: 2: 3. Cubic coefficients are usually intended unless specifically expressed. The less the substrate that expands when heated, the lower the chance of leaking, breaking or damaging the filter assembly. Lower thermal expansion is preferred to ensure that the substrate retains its dimensions when heated or cooled.

The coefficient of thermal expansion for an exemplary embodiment of the present invention is about 2.65 × 10 ⁻⁶ W / m-K (watts / meter Kelvin). Samples of cordierite is about ^{2.5 × 10 -6 W / m-} K~3.0 × 10 -6 W / m-K. The thermal expansion of the material of the present invention is less than 10 times that of cordierite.

  The coefficient of thermal expansion of the substrate is preferably comparable to that of any washcoat.

  In one embodiment, the catalyst substrate or filtration substrate of the present invention exhibits increased resistance to damage due to thermal or mechanical stress compared to certain prior art substrates such as cordierite; Or less clogged by ash; more tolerant to additional ash build-up when used with fuel additional regeneration; and has good efficiency for particle count reduction.

Density When considering the substrate to be used in a catalytic converter or diesel particulate filter, it is preferable to use a substrate having a low density. A material having a low density reduces the weight of the substrate and therefore the overall weight of the vehicle. Furthermore, the low density is complementary to the high porosity and permeability.

  The higher the density, the higher the weight. Weight is a major factor related to any engine in operation. The heavier the part, the greater the energy required to move it. In order for these filters to accommodate the increased volume of particles produced by the engine, the filter size must increase, which adds to vehicle weight and manufacturing and operating costs. Therefore, low density materials are desirable. Of course, the density is not so low that structural integrity is insufficient.

Another attribute of the substrate of the present invention is its density. The density of the substrate is lower than that of certain conventional filters and substrates used for filtration and as a catalyst substrate. Density is the ratio of the mass of a portion of a substance to its volume. The higher the density, the more energy is required to reach the operating temperature. In other words, heating a high density material requires more energy than a low density material. In determining the volume, it can be said that the greater the density, the greater the mass. Since the engine must work harder to move heavier equipment, weight is detrimental to vehicle mileage and performance. The increase in density also means that more heat is required to achieve the proper temperature at which catalytic activity or “ignition” occurs. The density of some materials currently used as substrates or filters is higher than optimal. For example, a cordierite sample is about 2.0-2.1 g / cm ³ . Accordingly, a substrate and filter having a lower density is needed. The density of the substrate of the present invention is lower than that of cordierite.

In one embodiment, the catalyst substrate of the present invention preferably has a low density. The density of the substrate of the present invention can range from about 2 to about 50 pounds / cubic foot (lb / ft ³ ). In a preferred embodiment, the density of the substrate ranges from about 5 to about 30 pounds / cubic foot, more preferably from about 8 to 16 pounds / cubic foot. Other preferred embodiments include catalyst substrates having a density of about 8, 9, 10, 11, 12, 13, 14, 15 or 16 lb / fg ³ . A low density that still provides structural integrity is preferred.

In one embodiment, the substrate of the present invention is about ^{8lbs / ft 3 ~22lbs / ft 3} , preferably has a density of about 8 lbs / ft ³ ~ about 22 lbs / ft ^3. In another embodiment, the substrate comprises a AETB-8 or AETB-16 having a density of about 8 lbs / ft ³ and about 16 lbs / ft ^3, respectively. Other suitable densities include densities selected from about 9, 10, 11, 12, 13, 14, 15, and 16 lb / fg ³ .

In another embodiment, the density of the substrate is from about 0.10 to about 0.25 g / cm ³ (grams / cubic centimeter).

Structural integrity The structural integrity of the substrate material is one characteristic that is important to consider. Structural integrity refers to the ability of a material to withstand vibration and mechanical stress, i.e. shaking and baking. For example, substrate strength is important to withstand package volume and use in subsequent engine exhaust flows including various stresses such as engine vibration, road impact and temperature gradients. High strength substrates are desirable for robust catalytic converter systems and particle filters. The strength of the substrate material can be controlled by the type of intra- and inter-crystal bonds, porosity, pore size distribution, and flaw population. Furthermore, the substrate can be reinforced by applying a chemical / material coating on the outside inside. The strength of the cell structure of the substrate can be further determined by its dimensions, cross-sectional symmetry and its cell attributes such as cell density, groove shape and wall thickness. The substrate strength must exceed the stress to which the material is exposed during both packaging and operation. If the stress exceeds the strength, the substrate will crack.

  The structural integrity of a material can be measured by the tensile modulus of the material. Tensile modulus is the resistance of a material to bursting. In particular, certain materials can draw large longitudinal stresses without tearing apart. Tensile modulus is usually expressed in terms of cross-sectional unit area, pounds / cubic inch, or kilogram / square centimeter required to cause rupture. Tensile modulus is related to whether the substrate can withstand the forces generated by intense exhaust gas flow pressures.

  Furthermore, the substrate should have good coverage so that a washcoat and / or catalyst coating can be applied to the substrate. Similarly, the substrate has washcoat compatibility and provides good loading of the catalyst on the substrate so that the catalyst is not driven out of their position during normal wear and tearing of the system. Good coverage and washcoat compatibility also enhances the long-term effectiveness of the catalytic converter system. Good coverage and washcoat compatibility also increases the life of the catalyst.

  Another attribute of the substrate of the present invention is its structural integrity. The structural integrity of a material can be measured by the tensile modulus of the material. Tensile modulus is the resistance of a material to bursting. In particular, certain materials can draw large longitudinal stresses without tearing apart. Tensile modulus is usually expressed in terms of cross-sectional unit area, pounds per square inch, or kilogram per square centimeter required to cause a rupture. Tensile modulus is related to whether the substrate can withstand the forces generated by intense exhaust gas flow pressures.

  The catalyst substrate of the present invention preferably has a higher tensile modulus. For example, in one embodiment, the substrate of the present invention has an axial strength of about 2.21 MPa. Of course, higher axial strengths are equally suitable. Other suitable values include 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 MPa.

  Furthermore, the structural integrity of the catalytic substrate of the present invention is such that it can withstand the conditions encountered during its use in catalytic converters in commercial vehicles.

  In another embodiment, the substrate of the present invention, such as nSiRF-C, preferably has high structural integrity and low density.

Contaminant Reduction The substrate plays an important role in enhancing the catalytic activity of the catalyst material coated thereon. In addition, the substrate is used to trap particulate material, which is then burned out as a volatile gas.

  Another advantage of the substrate of the present invention is its increased ability to reduce the amount of pollutants in the exhaust gas. The present invention has enhanced catalyst and filtration capabilities compared to certain conventional techniques.

  In certain embodiments, the substrates of the present invention can reduce CO emissions from exhaust gases by at least about 50%. In one embodiment, the substrate of the present invention may reduce CO emissions from exhaust gases by at least about 60%, 70%, 80% or 90%. In another embodiment, the substrate has a CO emission of at least 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%. Or it can be reduced by 100%.

  In certain embodiments, the substrates of the present invention can reduce NOx emissions from exhaust gases by at least about 50%. In one embodiment, the substrate of the present invention may reduce NOx emissions from exhaust gases by at least about 60%, 70%, 80% or 90%. In another embodiment, the substrate has at least 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9% NOx emissions. Or it can be reduced by 100%.

  In certain embodiments, the substrates of the present invention can reduce HC emissions from exhaust gases by at least about 50%. In one embodiment, the substrate of the present invention may reduce HC emissions from exhaust gases by at least about 60%, 70%, 80% or 90%. In another embodiment, the substrate has at least 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9% HC emissions. Or it can be reduced by 100%.

  In certain embodiments, the substrates of the present invention can reduce VOC emissions from exhaust gases by at least about 50%. In one embodiment, the substrate of the present invention may reduce VOC emissions from exhaust gases by at least about 60%, 70%, 80% or 90%. In another embodiment, the substrate has a VOC emission of at least 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%. Or it can be reduced by 100%.

  In certain embodiments, the substrates of the present invention can reduce PM-10 emissions from exhaust gases by at least about 50%. In one embodiment, the substrate of the present invention may reduce PM-10 emissions from exhaust gases by at least about 60%, 70%, 80% or 90%. In another embodiment, the substrate has a PM-10 emission of at least 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.99. It can be reduced by 9% or 100%.

  In certain embodiments, the substrates of the present invention can reduce PM-2.5 emissions from exhaust gases by at least about 50%. In one embodiment, the substrate of the present invention may reduce PM-2.5 emissions from exhaust gases by at least about 60%, 70%, 80% or 90%. In another embodiment, the substrate has a PM-2.5 emission of at least 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, It can be reduced by 99.9% or 100%.

Weight reduction Reducing the overall weight of the vehicle to improve vehicle fuel economy and engine efficiency is one goal of vehicle manufacturers. A heavy substrate adds unnecessary weight to the vehicle. Furthermore, if the substrate is not efficient enough to reduce contamination, more than one substrate may need to work together to reach the target contamination level. This greatly increases the overall weight of the vehicle.

  Furthermore, current catalytic converters require the use of additional equipment, which is often heavy and unwieldy. Some of these devices, such as heat shields and particle mats, are used to address the temperature of the catalytic converter. Others like oxygen sensors need to meet certain administrative regulations.

  In some embodiments of the invention, the catalyst substrate or filtration substrate exhibits a weight reduction compared to a conventional catalyst substrate or filtration substrate. This is due in part to the lower density of the substrate of the present invention compared to certain conventional substrates. Alternatively, the low weight may be due to the small amount of catalyst substrate or filtration substrate required due to the improved filtration and catalytic function of some embodiments of the present invention compared to the prior art. . The low weight of the catalyst substrate or filtration substrate has many benefits. For example, the low weight of the substrate translates into improved fuel efficiency for the vehicle. The lower weight translates into an engine device that is easy to handle and potentially safer to hold.

  In a preferred embodiment, the outer surface of the substrate does not become as hot during use as a conventional catalytic converter substrate. In some embodiments, the need for heat shields and / or insulation is reduced.

Acoustic attributes Acoustic attenuation can be defined as thickness reduction, thinning, grinding; density reduction; force or intensity reduction; or acoustic energy (sound) weakening. In one embodiment of the invention, acoustic attenuation is the ability of the substrate to attenuate or extinguish acoustic energy in the engine exhaust. The substrate of the present invention can replace or supplement an engine muffler assembly, as disclosed herein, and thus reduce exhaust noise and exhaust system costs. Higher sound attenuation is preferred.

  In another embodiment, the porosity, density and size of the substrate can be altered to “prepare” acoustic attenuation for the desired application.

  In another embodiment, the acoustic attenuation of the substrate may be combined with standard metal muffler-based techniques to mute and / or “tune” the sound present in the exhaust system.

Flow-through flow-through In one aspect, the substrate is constructed for flow-through use. Flow-through configurations are known in the art. In one embodiment, the grooves (or holes) are aligned parallel to each other over essentially the entire length of the substrate. The gas stream enters one end of the substrate, flows through the groove over the entire length of the substrate, and exits to the other side.

  Any number of flow-through configurations are useful and suitable for the catalyst substrate of the present invention. Flow-through configurations known in the art can be applied to the catalyst substrate of the present invention.

  In one embodiment, the flow-through configuration includes a plurality of substantially parallel grooves that extend across the length of the substrate.

  In another embodiment, the groove walls are not parallel to the sides or surface of the substrate.

Wall Flow Another embodiment of the present invention is the catalyst substrate or filtration substrate of the present invention configured in a wall flow configuration. Surprisingly, it has been determined that a catalyst substrate comprising nSiRF-C of the present invention can be configured in a wall flow configuration.

  In another aspect of the invention, the substrate has a wall flow configuration. For example, the substrate is used in a wall flow catalytic converter or wall flow particle filter. The wall flow configuration can take any one of a number of physical arrangements. A substrate having a wall flow configuration may have one or more attributes as described herein. In addition, the substrate having a wall flow configuration may further include one or more of the following: catalyst, washcoat, oxygen storage oxide and emissivity enhancer. Further, the substrate comprising a wall flow configuration can be further modified, strengthened, or altered as described herein.

  In one embodiment, the groove wall thickness is any of the following values: A groove wall thickness of about 2 mils to about 6 mils is preferred. In other embodiments, the groove wall thickness ranges from about 10 mils to about 17 mils. Other suitable values include 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 mils.

  In other embodiments of the wall flow substrate, the cell density of the substrate is about 400 cpsi (cells per square inch) and the wall thickness is about 6 mils, or the cell density is about 900 cpsi and the groove wall thickness is about 2 It is a mill. Additional embodiments include those where the cpsi is about 50, 100, 150, 200, 250, 300, or 350.

  Ceramic wall flow monoliths derived from flow-through cell supports used for catalytic converters have become the most common type of diesel filter substrate. They are distinguished from other diesel filter designs by high surface area / unit volume and by high filtration efficiency. A monolith diesel filter consists of a number of small parallel grooves, typically having a square cross-section, that run along the axis throughout the part. A diesel filter monolith is obtained from a flow-through monolith by plugging the groove. Adjacent grooves are plugged alternately at each end to propel the diesel aerosol through the porous substrate wall acting as a mechanical filter. To represent this flow pattern, the substrate is called a wall flow monolith. Wall flow monoliths are most commonly used in cylindrical shapes, but elliptical cross-section parts are also possible for space constrained applications.

  Wall flow filter walls have a fine pore distribution that must be controlled in the manufacturing process. The filtration mechanism for monolith wall flow filters is a combination of cake and depth filtration. As the particles are deposited inside the pores, depth filtration is the dominant mechanism on the clean filter. As the amount of soot increases, a particle layer develops in the inlet groove wall, making cake filtration a widely used mechanism. Some conventional monolith filters have a filtration efficiency of about 70% of total particulate matter (TPM). Higher efficiencies can be observed for solid PM fractions such as elemental carbon and metal ash.

  In accordance with certain embodiments of the present invention, a material that is porous and therefore allows more gas to pass through the pores and interacts with the catalyst deposited in the core of the fibrous composite material. It is preferable to have. In addition, having a porous wall allows higher depth filtration in certain embodiments, which may also be a desirable attribute.

  The substrate of the present invention in the wall flow configuration is much more in direct contact with the exhaust gas. Material pore characteristics (size, porosity%, pore connectivity, open versus closed pores, etc.) affect the physical interaction between the gas and the filter material and affect attributes such as filtration efficiency and pressure drop. Furthermore, the substrate durability depends on the material resistance to chemical attack by the exhaust gas constituents. In particular, the material needs to be resistant to corrosion by metal ash, which can be part of the diesel particles. Resistance to sulfuric acid corrosion is also required, especially when the filter is used with a high sulfur content fuel. Furthermore, due to the possibility of releasing large amounts of heat during filter regeneration, the filter material is required to exhibit excellent thermal properties in terms of resistance to both high temperatures and high temperature gradients. Insufficient temperature tolerance can result in melting of the material, while insufficient thermal shock resistance causes cracking. Other potential problems include microcracking and crushing. In certain embodiments, the filtration substrate and catalyst substrate of the present invention solve one or more of these problems.

  Important considerations when designing the exact geometry of a wall flow monolith include the following parameters: cell density, repeat distance (uniform distribution of pressure drop across all wall flow filters), wall thickness, Surface area before release, specific filtration area, and mechanical integrity factors.

  In a specific embodiment of the invention, half of the walls of the wall flow configuration are blocked. In another configuration, the substrate of the present invention has a wall flow configuration in which the groove blocking wall is configured at the beginning or end of the groove. In another configuration, the barrier wall is placed in the middle of the groove, or alternatively, anywhere between the beginning and end of the groove.

  Furthermore, any percentage of grooves, such as 10%, 25%, 50%, 75%, 90%, 95%, etc. may be included in the wall flow configuration.

Grooves and groove openings In one embodiment, the catalyst substrate or filtration substrate does not contain a plurality of grooves extending across the length of the substrate. In certain embodiments, the catalyst substrate or filtration substrate is placed in the substrate such that, in view of its porosity and permeability, the substrate functions in its intended application, for example, in a catalytic converter. There is no need to have grooves. Any potential back pressure is mitigated by porosity and permeability by simply placing the exhaust in the catalyst substrate path. If a membrane configuration without grooves is used, the preferred use is in a low flow environment to reduce the chance of structural substrate failure. The thin film configuration is preferably used in a “low flow” environment, for example in a fireplace or perhaps a power plant. Here the flow rate is low and in some cases constant (power plant). Of course, it will be appreciated that such a configuration is suitable for other uses as well, such as for vehicles and stationary engines.

  In another embodiment, the catalyst substrate or filtration substrate of the present invention, in one embodiment, has a plurality of grooves extending longitudinally through at least a portion of the substrate. The plurality of grooves cause a fluid medium, such as a gas or liquid, to flow through the substrate. The plurality of grooves extend from the front surface to the rear surface. The other groove extends from the rear surface to the front surface.

  The groove can extend through the entire length of the substrate. In such an embodiment, the groove has a first groove opening on the front surface of the substrate and a second groove opening on the rear surface. Alternatively, the groove extends through a portion of the substrate. In some embodiments, the groove extends through about 99%, 97%, 95%, 90%, 85%, 80%, 70%, 60% or 50% of the length of the substrate.

  The slot or slot opening in the substrate can be formed in any number of shapes. For example, the groove openings can be circular, triangular, square, hexagonal, etc. In a preferred embodiment, the groove openings are triangular, square or hexagonal.

  In one embodiment, the groove openings are formed such that the thickness of the substrate material between adjacent grooves is substantially uniform across the substrate. The wall thickness variation may be about 1% to about 50% in some embodiments.

  In another embodiment, the grooves are aligned so that the walls of adjacent grooves are parallel to each other. For example, triangular, square or hexagonal grooves can be formed such that the walls of adjacent grooves are parallel to each other.

  The diameter or cross-sectional distance of the grooves in the substrate of the present invention can vary. In some embodiments, the groove has a diameter or cross-sectional distance of about 5 cm to about 100 nm. In some embodiments, the groove has a diameter of about 100 nanometers. Other suitable values are from about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 mils. The distance or diameter selected is mentioned.

  The groove can vary in size along its length. For example, the groove has a cross-sectional distance at its opening of about 0.04 inches and then gradually reduces in size as it approaches the groove's end wall or point, or the groove's end opening. In one embodiment, the groove is a square opening at the front surface having sides of about 10 mils. The groove extends from end to end in the length of the substrate and has a second opening on the rear surface. The rear surface groove opening has a square shape with sides of about 4 mils. The groove gradually decreases along its length from the front surface to the rear surface. Other similar configurations are of course contemplated.

  The size of the groove opening can vary as well. For example, in certain embodiments, the diameter (or cross-sectional distance) is from about 1 mil to about 100 mils. Other suitable ranges for the size of the groove openings include, but are not limited to, about 1 to about 500 mils, about 1 to about 100 mils, about 1 to about 10 mils. Other suitable sizes include from about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 mils. The distance or diameter selected is mentioned. The substrate of the present invention also has grooves of various sizes. That is, some grooves of an embodiment of the substrate have a first plurality of grooves having a first diameter or cross-sectional distance and a second plurality of grooves having a second diameter or cross-sectional distance. By way of example, the substrate of the present invention, in one embodiment, includes one or more grooves having a cross-sectional distance of about 5 mils, and further includes one or more grooves having a cross-sectional distance of about 7 mils. Including. It will be understood that other variations of these embodiments are within the scope of the present invention.

  In other embodiments, the groove diameter or cross-sectional distance can be about 5 cm, 4 cm, 3 cm, 2 cm, or 1 cm. For large exhaust systems that can have exhaust pipes that are one foot or more in diameter, substrates with larger diameter or cross-sectional distance grooves are preferred.

  The groove wall thickness can vary as well. For example, the groove wall can be less than 1 mil thick. Other suitable values for groove wall thickness include 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 mils.

  Grooves can be measured in terms of grooves / square inch. In some embodiments, the substrate of the present invention has about 50 to about 100,000 grooves per square inch. Other suitable values include 100, 200, 300, 400, 500, 600, 700, 800, 900 and 1,000. Other embodiments include catalyst substrates or filtration substrates having 2,000 / in 2 grooves.

  In one embodiment, the substrate of the present invention comprises 600 cpsi and a wall thickness of 6 mils. The cell density of the sample substrate of the present invention is compared with two cordierite samples. The first and second cordierite samples are 100 cpsi, wall thickness 17 mil, and 200 cpsi, wall thickness 12 mil, respectively. In comparison, the substrate of the present invention has 600 cpsi and 6 mil walls in this embodiment.

  In an exemplary embodiment, the substrate is perforated with 0.04 inch diameter grooves at 0.06 inch intervals throughout the filter. These grooves are smaller than conventional cordierite wall flow grooves. As a result, a much larger and increased surface area is produced compared to cordierite without taking into account the surface area present in the large pore space of the substrate material. The groove is preferably a “blind” groove. Rather than flowing through and out of the groove without reaction with the catalyst, the exhaust exhaust is swept through the groove wall.

  Further embodiments are directed to catalyst substrates or filtration substrates that include a plurality of grooves having a pyramid shape. The pyramid-shaped grooves are such that they can be applied to any number of substrate materials, such as, for example, nSiRF-C in addition to the substrate of the present invention. The pyramid shaped grooves can be configured in a flow-through configuration, for example with one on the front surface of the substrate and one on the back surface of the substrate, such that each groove has two groove openings. Alternatively, the pyramid shaped grooves can be configured, for example, in a wall flow configuration so that each groove has only one opening. In this embodiment, certain groove openings are located on the front surface, while other groove openings are located on the rear surface. Preferably the grooves are positioned such that the adjacent grooves have the opposite configuration with respect to the position of the groove opening. Further, in certain embodiments of the pyramidal wall flow configuration, the groove terminates at a non-perforated portion of the substrate. This non-perforated portion of the substrate is flat or pointed. If the non-perforated part is flat, the longitudinal cross section of the groove appears trapezoidal. When the non-perforated part is pointed, the longitudinal cross section of the groove looks like a triangle.

Shapes and forms Catalysts and filtration substrates include many suitable and thus unknown configurations. The substrate is three-dimensional and generally has a front surface (or region or surface) and a back surface (or region or surface) that are connected to one or more side surfaces by the substrate body. The front and back surfaces can be any number of shapes as described herein. The front surface refers to the surface through which fluid enters the substrate. The back surface refers to the surface through which fluid exits the substrate. In general, the surface is flat, but in some embodiments it may be non-planar.

  In some embodiments, the substrate has a cylindrical shape. The cylindrical shape constituting the substrate is used, for example, to catalyze the reduction of NO in the exhaust gas.

  Any number of suitable lengths and widths or diameters are suitable for the substrate of the present invention. Suitable lengths include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 inches. . Of course, longer lengths may be preferred in diesel applications and for use in stationary engines such as pharmaceutical and chemical factories, manufacturing factories, power plants, and the like. In another respect, the shape of the substrate can be described based on its front surface shape. The substrate of the present invention can be prepared such that the front surface has one of several physical configurations. The front surface shape is an arbitrary number of shapes, and examples thereof include, but are not limited to, a circle, a triangle, a square, an ellipse, a trapezoid, and a rectangle. In three dimensions, the substrate can be cylindrical or substantially flat disk shaped. Commercially available substrates generally exist as one of these three designs. The substrate can have angular corners or rounded corners. Rounded corners are preferred in the front surface shape of the substrate. Thus, in one embodiment, the substrate of the present invention has a square shape with rounded corners. In another embodiment, the substrate has a rectangular front surface shape with rounded corners. In another embodiment, the substrate has a trapezoidal front surface shape with rounded corners.

  Exemplary dimensions of the catalyst substrate of the present invention have a circular cross-sectional shape and are about 3.66, about 4.00, about 4.16, about 4.66, about 5.20, about 5. Examples include, but are not limited to, those having a diameter of 60 or about 6.00 inches. In other embodiments, the catalyst substrate has a cross-sectional dimension of about 3.15 × about 4.75 inches, about 3.54 × 5.16 inches, or about 4.00 × about 6.00 inches (each short An elliptical cylindrical shape having an axis and a major axis.

  In another embodiment, the catalytic substrate has a shape and size suitable for use in a head catalytic converter. In general, head catalytic converters will be smaller in size than conventional catalytic converters found in engine exhaust systems. Determination of the appropriate size and shape of the head catalytic converter is within the ability of one skilled in the art. The size and shape of the head catalytic converter is configured based on the specific head and engine in which the head catalytic converter will be used. For example, a conventional round cordierite substrate having a diameter of about 4 and 1/2 inches has a front surface area of about 28.27 square inches. For Ford 4.6V-8, for example, there are two pre-catalytic converters having a substrate of approximately this size. These two conventional pre-catalytic converters can be replaced by an eight-head catalytic converter that includes an nSiRF-C substrate about 1.13 inches in diameter.

  Alternatively, the cylinder is used to catalyze the oxidation of carbon monoxide and non-burning hydrocarbons in the exhaust gas. The length of the cylinder may be longer, equal to or shorter than the diameter of the cylinder.

  Different shapes and configurations of the filtration substrate and the catalyst substrate can be used based on a particular application, such as stationary engines, on-road vehicles, off-road vehicles, and the like.

  In another embodiment, the catalytic substrate is shaped to replace the commercially used substrate of a commercial catalytic converter. In this embodiment, the substrate of the present invention has a shape and dimensions that are substantially the same as the substrate of an available catalytic converter that uses a different substrate. For example, many commonly used catalytic converters contain a substrate made from cordierite. The shape and size of the catalytic converter cordierite is known or can be determined by analysis. The substrate of the present invention is then machined or molded as described below so that the shape and size of the substrate of the present invention is substantially the same as that of known cordierite substrates. Is prepared.

The membrane configuration or the substrate has a membrane configuration. In such a configuration, the length of the substrate is substantially shorter than the width or diameter of the substrate. The longer travel length for exhaust through the substrate corresponds to increased back pressure in certain conventional catalytic converters and particle filters. In a thin substrate of an embodiment of the present invention, back pressure is minimized and the exhaust gas will travel through a filter system with low working force and increased filtration capacity. This reduction in back pressure results in more efficient engine operation, which means better gas mileage and greater power.

  In one embodiment of the present invention, the substrate is 2 inches in diameter, 1/16 inch in thickness, and has a surface area 400 times that of a conventional cordierite filter having a diameter of 4 inches and a length of 6 inches. . Since the substrate itself has been reduced in size, the canister can also be reduced in size, producing only a small bulge in the exhaust line. Alternatively, the substrate can be housed in an exhaust manifold.

  In another embodiment, the substrate is in the form of a membrane. In this case, the membrane comprises a substrate material as described herein having any number of shapes as described above, and in this case the length of the substrate is substantially shorter than the width or diameter. . The dimension can be described, for example, as a width-to-length or diameter-to-length ratio. Suitable diameter to width ratios are about 20: 1, 19: 1, 18: 1, 17: 1, 16: 1, 15: 1, 14: 1, 13: 1, 12: 1, 11: 1, Examples include, but are not limited to 10: 1, 9: 1, 8: 1, 7: 1, 6: 1 and 5: 1.

  Further, a substrate having a membrane configuration can be stacked together with one or more substrate embodiments. With respect to the membrane configuration, many catalyst substrates or filtration substrates having a membrane configuration can be stacked together. For example, a plurality of, for example, five catalyst substrates or filtration substrates having a cylindrical (or disk) shape with a diameter of about 1 inch and a length of about 0.2 inch are stacked together to form a length, for example about A substrate pile having a length of 1 inch may be formed.

  In the case of a membrane configuration, in one embodiment, the catalyst substrate does not contain a plurality of grooves that travel through the substrate. A substrate pile comprising a plurality of catalyst substrates having a membrane configuration due to the shorter distance that the gas must travel, and in part due to the high porosity of the present invention and the low pressure drop caused by the present invention. Can be formed.

  Stack membrane configurations also include stacked membrane configurations where the individual substrates are not perpendicular to the catalytic converter or particle filter bed. In this embodiment, the angle between the side (s) (outer side) and the side (front or back surface) of the substrate is about 90 °, less than or greater than 90 °. Alternatively, the substrate can be machined or molded to be, for example, 80 °, 70 °, etc.

Pre-sintering addition of catalyst In another embodiment, a catalytic substrate as described herein further comprises a catalyst, wherein the catalyst is added to the substrate material prior to the sintering process. In this case, the catalyst is generally added to the slurry before the green billet is produced. In other embodiments, the catalyst is added to the fibers in a mixer. Alternatively, the catalyst, if in liquid form, is added to the slurry in some embodiments. The substrate can be formed from a slurry containing one or more catalysts. In one embodiment, the catalyst adheres to the substrate fibers during sintering. In another embodiment, the catalyst is located in the pores of the groove wall as opposed to those that are primarily attached to the surface of the groove wall.

Substrate Band Distribution In another embodiment, a catalyst substrate as described herein is prepared such that different zones in the substrate have different attributes. In other words, one or more physical characteristics or attributes of the catalyst substrate are not uniform or identical throughout the substrate. For example, in certain embodiments, different zones or regions of the substrate have different densities, different catalysts, different catalyst mixtures, different groove configurations, different porosity, different permeability and / or different thermal attributes. By way of example, in one embodiment, the catalyst substrate of the present invention comprises an nSiRF-C composite material and first and second catalysts, wherein the first catalyst is applied to the first zone of the substrate. And the second catalyst is applied to the second zone of the substrate. In further embodiments, the substrate has different degrees of structural integrity across the entire body of the substrate. For example, as described herein, a compression toughening coating is added to the surface of the substrate to increase the hardness of the surface, which reduces possible damage.

Washcoat Another aspect of the present invention is directed to a catalyst substrate or filtration substrate as described herein further comprising a washcoat. In other embodiments, the catalyst substrate further includes a catalyst washcoat, eg, the catalyst washcoat includes a catalyst in addition to the washcoat material. Alternatively, in another embodiment, the washcoat material has catalytic activity.

  Suitable washcoats include silica, titania, unimpregnated zirconia, zirconium impregnated with rare earth metal oxide, ceria, co-generated rare earth metal oxide-zirconia, and combinations thereof. Other suitable washcoats are described in, for example, Patent Document 20, Patent Document 21, Patent Document 22, Patent Document 23, Patent Document 24, and Patent Document 25, all of which are incorporated herein by reference. Are disclosed.

  In general, the washcoat may be applied from an aqueous slurry in certain embodiments. Alumina powder and / or other washcoat oxides are ground to the required particle size. The particle size distribution of the washcoat powder affects the mechanical strength of the finished washcoat and its adhesion to the substrate, as well as the rheological attributes of the slurry during the washcoat process. Alumina, which is a very hard material, is ground in some embodiments using an air jet or ball mill.

  In the next step, the material is dispersed in acidified water in a tank using a high shear mixer. The solids content in the slurry is typically 30-50%. After mixing for a long time, the alumina suspension becomes a stable colloidal system.

  The amount of washcoat deposited on the substrate depends on and can be controlled by the rheological attributes (viscosity) of the slurry. The aluminum oxide slurry is in some cases a non-Newtonian fluid that changes its viscosity with time and with the amount of mechanical energy (shear rate) supplied to the system. At any steady shear rate, the viscosity of the slurry is a function of its pH. In certain embodiments, the viscosity can be controlled by pH adjustment. However, due to the non-Newtonian nature of the alumina system, precise viscosity control is probably the biggest challenge in the washcoat process.

  The washcoat slurry can be applied to the substrate by any known method and technique, such as by dipping or pouring onto parts and / or with a special coating machine. Excess slurry is swept from the groove with compressed air. The substrate can then be dried and fired to bond the washcoat to the monolith wall.

  In some embodiments, the washcoat may be applied in one, two or more layers. After each layer is dried and fired, the next layer is processed. There are several reasons for the application of multi-layer washcoats: (1) catalyst design requires different chemical formulations for each layer, and (2) coating / process equipment constraints, such as a thick washcoat in a single operation It is not possible to handle highly viscous slurries that need to be applied.

The typical thickness of the washcoat layer is 20-40 μm, but values outside the range can also be used in the present invention. These numbers correspond to, for example, a washcoat amount of about 100 g / L on a 200 cpsi substrate to about 200 g / L on a 400 cpsi substrate. The specific surface area of the catalyst washcoat material is 100-200 m ² / g in some embodiments. Of course, other values are useful herein.

  The noble metals and other catalysts in the composite catalyst system can react with each other, with the washcoat components, or with the support material to produce undesirable catalytically inert compounds. If such reactions occur with a given catalyst system, they are difficult to prevent with conventional washcoat techniques. Since the catalytic metal is impregnated on the finished washcoat layer, contact between the reaction components is inevitable.

  Separation washcoat technology was developed to physically separate noble metals by immobilizing the noble metal on a particular base metal oxide of the washcoat before the washcoat is applied onto the substrate. By using washcoat layers with different oxides and / or noble metals, the components of the catalyst system can be separated. Additional benefits of this technique include control of the noble metal / base metal ratio and improved noble metal dispersion. Such a technique can be applied to the present invention. Thus, in a preferred embodiment, the present invention is directed to a catalyst substrate comprising nSiRF-C, at least two catalytic metals, and a washcoat, wherein the two catalytic metals are physically separated.

Segregated Washcoat Schematic: A separate washcoat was applied to a three-way catalyst for automobiles. Examples of such catalysts are trimetallic systems containing platinum, palladium and rhodium. The first layer of catalyst consists of Pd / Al ₂ O ₃ . The second layer (surface layer) is made of Rh / Pt / Ce-Zr. This design prevents the formation of palladium-rhodium alloys that could otherwise cause catalyst deactivation.

Aluminum oxide or alumina is the basic material for the exhaust control catalyst washcoat. The high surface area γ crystal structure (γ-Al ₂ O ₃ ) is used for catalyst applications. This is characteristic at high purity. The presence of certain components in Al ₂ O ₃ can affect its thermal stability for better or worse. A small amount of Na ₂ O present in Al ₂ O ₃ acts as a solvent and promotes sintering of alumina. In contrast, some metal oxides including La ₂ O ₃ , SiO ₂ , BaO, and CeO ₂ have a stabilizing effect on the alumina surface area and their sintering rate is reduced. Stabilized alumina is commercially available.

In another embodiment, cerium dioxide, or ceria is a component of the catalyst washcoat that is added, for example, in an amount up to 25%. In another embodiment, ceria is added in amounts of about 5%, 10%, 15%, 20%, and 25%. Ceria is an important promoter in automobile exhaust control catalysts. One function of ceria in the three-way catalyst is oxygen storage, which is possible by circulation between Ce ⁴⁺ and Ce ³⁺ . Other effects of ceria include stabilization of alumina, promotion of steam reforming reaction, promotion of precious metal dispersion, and precious metal reduction.

  Some diesel oxidation catalyst formulations contain high loadings of ceria. The function of ceria is the oxidation / cracking of the catalyst of the soluble organic fraction of diesel particles.

High surface area cerium oxide can be produced, for example, by firing a cerium compound. The BET surface area of ceria can be as large as 270 m ² / g. In another embodiment, for example, ceria with a surface area of about 150 m ² / g is used with a three-way catalyst. High temperature stabilized types that can withstand 900-1,000 ° C. have a surface area of about 6-60 m ² / g and are suitable for use in the present invention.

  In another embodiment, the catalyst substrate or filtration substrate of the present invention further contains zirconium oxide. In some embodiments, zirconium oxide increases the thermal stability of the substrate.

Titanium dioxide is used with some diesel catalysts as an inert non-sulfurized support. Two important crystal structures of titanium dioxide include anatase and rutile. The anatase form is important for catalytic applications. It has a surface area of up to 50~120m ² / g, there is a thermally stable up to 500 ° C.. The rutile structure has a small surface area of less than 10 m ² / g. The conversion of anatase to rutile is performed at about 550 ° C., leading to catalyst deactivation. In another embodiment of the invention, the catalyst substrate contains nSiRF-C, preferably AETB or OCTB, a catalyst, and titanium oxide.

Zirconium oxide can be used as a three-way catalyst for automobiles as a ceria heat stabilizer and promoter, or as a non-sulfurized component of a diesel oxidation catalyst washcoat. Zirconium oxide has a BET surface area of 100 to 150 m ² / g. At 500-700 ° C its surface area looses rapidly. Good thermal stability can be achieved by extensive use of dopants including La, Si, Ce, and Y.

Zeolites are synthetic or naturally occurring alumina-silicate compounds that have a well-defined crystal structure and pore size. The size of the zeolite pore is generally 3 to 8 mm and falls within the molecular size range. Any molecules with a larger cross-sectional area are prevented from entering the groove of the zeolite cage. For this reason, zeolites are often referred to as molecular sieves. Zerolite is characterized by a large specific surface area. For example, ZSM-5 zeolite has a surface area of about 400 m ² / g. Zeolite mordenite has a surface area of about 400-500 m ² / g. Most zeolites are thermally stable up to 500 ° C.

Some catalytic zeolites are ion exchanged with metal cations. The acid form (HZ) of the zeolite is first treated with an aqueous solution containing NH ⁴⁺ (NH ₄ NO ₃ ) to form an ammonium exchanged zeolite (NH ⁴⁺ Z ⁻ ). It is then treated with a salt solution containing catalytic cations to form a metal exchanged zeolite (MZ).

  Zeolites are excellent adsorbent materials because of their repetitive and well-defined pore structure. They have been used as adsorbents in many applications, including drying, purification and separation. Synthetic zeolites are also used as catalysts in petrochemical processing.

Recently, zeolite, as catalyst (SCR, low quality the NO _x catalyst), and as an adsorbent (hydrocarbon traps in diesel oxidation catalyst), have been used increasingly for the diesel exhaust control.

  It is understood that further embodiments of the invention include any of the specific substrate embodiments described herein, further including any of the specific washcoat embodiments.

Oxygen storage oxide In another embodiment, the catalyst substrate or filtration substrate of the present invention further comprises an oxygen storage oxide. An oxygen storage oxide (for example, CeO ₂ ) has an oxygen storage capacity (hereinafter abbreviated as “OSC”), that is, an ability to occlude gaseous oxygen and to exhaust the occluded oxygen. More specifically, in an oxygen-rich state (ie, a fuel-lean state, which may be referred to simply as a “low-quality state”) in a gaseous atmosphere to assist the catalytic converter that reduces NOx to N ₂ . CeO ₂ is added to adjust the oxygen concentration in the gas atmosphere so as to occlude excess oxygen into the crystal structure of CeO ₂ , while assisting the catalytic converter to oxidize CO and HC to CO ₂ and H ₂ O Therefore, in the CO- and / or HC-rich state (that is, the fuel-rich state that may be simply referred to as “rich state”), the stored oxygen is discharged into the gas atmosphere. Thus, the catalytic activity of the catalyst substrate is increased by the addition of CeO _2. As disclosed in Patent Document 26, other oxide storage oxides include Pr ₆ O _{11 and the} like. Further embodiments include any specific substrate embodiments described herein further comprising an oxygen storage oxide (eg, CeO ₂ ).

SO _x oxidation In the presence of certain metal catalysts, especially platinum, the sulfur present in the fuel, eg diesel fuel, is converted to SO _x , which in turn exhausts sulfur compounds that are harmful to the environment, eg sulfuric acid gas. Can occur. Most sulfates are typically produced on platinum catalysts at relatively high exhaust temperatures of about 350-450 ° C. While there is an extreme need to remove sulfur from gasoline and diesel fuel formulations, catalyst formulations have sought to reduce that problem to the extent possible.

An exemplary platinum catalyst developed by Engelhard consists of 5 to 150 g / ft ³ of Pt / Rh in a 5: 1 ratio, and 30 to 1,500 g / ft ³ of MgO (US Pat. The catalyst can be impregnated on the substrate with a water-based solution. The filter coated with the catalyst is preferably regenerated using an exhaust temperature of 375 to 400 ° C. Function of rhodium in the above formulation, catalytic oxidation of SO _2, thus suppresses the sulphate cover the catalyst.

  The catalyst substrate of the present invention provides a solution to these problems in certain embodiments, for example, by having an improved thermal profile and thereby reducing catalyst pyrolysis.

  Catalyst poisoning is a significant source of catalyst deactivation. It can occur when substances present in the exhaust gas chemically deactivate the catalytic site or cause deposits on the catalyst surface. Poisons in exhaust gases from internal combustion engines can originate from lubricating oil components or from fuel.

The interaction between different catalyst species or between the catalyst species and the support component is another temperature-induced mode of catalyst deactivation. An example is the reaction between rhodium and CeO ₂ in an automotive 3-way catalyst. This type of problem can be reduced by using an alternative support, as well as special washcoat techniques known in the art, which physically separate the reaction components.

  A further advantage of the present invention is that nSiRF-C can be pumped in different zones to physically separate incompatible components, or stacking with incompatible components in separate membrane substrates. It can be used as a film configuration.

  Catalyst deactivation can also occur due to physical washcoat loss due to corrosion and wear. The mechanism may also be important for emission control catalysts due to high gas velocities, temperature changes, and differences in thermal expansion between washcoat and substrate materials.

Catalyst coating In certain applications, an adsorbent catalyst is used to convert NO to a salt, which can then be manually removed in a regeneration process. However, the presence of sulfur in the fuel can result in the formation of insoluble SO ₄ salts, such as barium sulfate, which can form a protective coating on top of the catalyst, reducing their efficiency. An advantage of certain embodiments of the present invention is that the catalyst substrate is less susceptible to reduced efficiency due to coating from sulfate.

  In another embodiment, the catalyst substrate or filtration substrate of the present invention further comprises a protective coating suitable for ceramic. For example, such a suitable protective coating is disclosed in US Pat. This coating is also known as a protective coating (PCC) for ceramic materials. Another suitable and related coating is available as an Emissshield (R) coating (Wessex Incorporated, Blacksburg, VA). The emissivity agent in Emissiel® enhances the emissivity in the material, especially at high temperatures. In addition, the protective coating can reduce damage from external impacts and wear forces. Appropriate coatings are disclosed in US Pat. Nos. 6,099,069 and 3,057,037, the disclosures of which are hereby incorporated by reference. The above coatings can be used with one or more specific filtration and catalyst substrates described herein.

  In certain embodiments, the catalyst substrate or filtration substrate is resistant to damage from thermal shock and thermal cycling. However, certain substrates are relatively soft and can be damaged by external impacts and wear forces. In order to reduce such damage, in a preferred embodiment, the catalyst substrate or filtration substrate of the present invention further comprises one or more protective coatings on the surface of the substrate, preferably the outer surface. Examples of suitable protective coatings are disclosed in US Pat. Thus, in a preferred embodiment, the present invention provides a substrate having higher porosity, higher permeability, and sufficient hardness, compared to conventional substrates, among other attributes. The above coatings can be used with one or more specific filtration and catalyst substrates described herein.

Pressure Drop The present invention also provides a substrate with pressure drop improvements for catalytic converters and particle filters. Thus, in certain embodiments, the substrate of the present invention removes exhaust gases without substantial increase in back pressure or with a lower back pressure increase compared to conventional catalysts and particle filters. Means for filtering are provided.

  Exhaust gas flow through conventional catalytic converters creates a substantial amount of back pressure. Increased back pressure in catalytic converters is an important attribute for the success of catalytic converters. If the catalytic converter is partially or totally clogged, it will limit the exhaust system. Subsequent increases in back pressure cause a dramatic drop in engine performance (eg, horsepower and torque) and fuel economy, and if the shut-off is severe, it can even cause the engine to stop after it starts. Conventional efforts to reduce pollutant emissions are very costly, both because of the cost of the material, as well as the cost of retrofitting or manufacturing an original engine with appropriate filters.

  The substrate of the present invention has the attribute that, in certain embodiments, it produces a lower or less pressure drop than conventional substrates used in catalytic converters or particulate filters. The present invention, in some embodiments, has lower soot stacking in the particle filter compared to conventional particle filters, and in some cases, the need for filter replacement is less frequent.

Specific Embodiments The present invention is also directed to specific embodiments of the above catalyst and filtration substrate. Specific embodiments include a substrate comprising, consisting of, or consisting essentially of nSiRF-C and a catalyst. An additional embodiment is a filtration substrate that includes nSiRF-C and a plurality of grooves.

  For example, an embodiment of the substrate has a plurality of the above attributes. In other embodiments, the substrate of the present invention has 2, 3, 4, 5, 6, 7, 8, 9 or 10 attributes as described above. Specific embodiments may include any combination of attributes. The catalyst substrate is further illustrated by the following non-limiting specific embodiments.

In one embodiment, the substrate of the invention has a porosity of about 96% to about 99%; a density of about 10 to about 14 lb / ft ³ ; a plurality of grooves having a wall flow configuration; and optionally a catalyst. Includes nSiRF-C composite.

In one embodiment, the substrate of the present invention has a porosity of about 96% to about 99%; about 10 to about 16 lb / ft ³ , preferably about 10, 11, 12, 13, 14, 15 or 16 lb / An nSiRF-C composite having a density of ft ³ ; alumina boria silica fibers, silica fibers and alumina fibers having a plurality of grooves with a wall flow configuration; and optionally a catalyst. In other embodiments, the substrate preferably further comprises a washcoat of alumina oxide or derivative thereof.

In another embodiment, the substrate of the present invention comprises a substrate having one or more of the following attributes: tensile strength of about 100 to about 150, preferably about 130 to 140, more preferably 133 psi; BTU-ft ^* / hr ft ² ° F. thermal conductivity of about 0.5 to about 0.9, preferably about 0.7 to about 0.8, more preferably about 0.770; about 1 to about 5 × ^{10 -6,} about 1 to about 3 × ^{10 -6,} more preferably the thermal expansion coefficient of about 1.95 × ^{10 -6} (tested at 77 ° F~1,000 ° F); about 15.5～ about 17, an average density of about 16 to about 16.8, more preferably about 16.30 / lb / ft ³ ; and optionally a catalyst.

In another embodiment, the substrate of the present invention comprises a substrate having one or more of the following attributes: a tensile strength of about 50 to about 70, preferably about 60 to 65, more preferably 63 psi; BTU-ft ^* / hr ft ² ° F. thermal conductivity of about 0.5 to about 0.9, preferably about 0.7 to about 0.8, more preferably about 0.770; about 1 to about 5 × ^{10 -6,} (tested at 77 ° F~1,000 ° F) from about 1 to about 3 × ^{10 -6,} more preferably the thermal expansion coefficient of about 1.77 × ^{10 -6;} about 7 to about 9, Preferably an average density of about 8.2 to about 8.6, more preferably about 8.40 / lb / ft ³ ; and optionally a catalyst.

In another embodiment, the substrate of the present invention comprises a substrate having one or more of the following attributes: tensile strength of about 60 to about 80, preferably about 70 to 79, more preferably 74 psi; A thermal conductivity of BTU-ft ^* / hr ft ² ° F. of about 0.5 to about 0.9, preferably about 0.7 to about 0.8, more preferably about 0.765; × ^{10 -6,} about 1 to about 3 × ^{10 -6,} more preferably the thermal expansion coefficient of about 1.84 × ^{10 -6} (tested at 77 ° F~1,000 ° F); from about 9 to about 11, Preferably an average density of about 9.5 to about 10.5, more preferably about 10 lb / ft ³ ; and optionally a catalyst.

Another suitable catalyst substrate of the present invention is nSiRF-C as described herein; as well as a catalyst comprising: a support pre-doped with copper oxide (CuO); platinum (Pt) At least one noble metal as a main catalyst selected from the group consisting of palladium, Pd, rhodium (Rh) and rhenium (Re), where at least one noble metal is doped on the surface of the pre-doped support And at least one metal oxide as a co-catalyst selected from the group consisting of antimony trioxide (Sb ₂ O ₃ ), bismuth trioxide (Bi ₂ O ₃ ), tin dioxide (SnO ₂ ), and mixtures thereof ( Where at least one metal oxide is doped on the surface of the pre-doped carrier). Such a catalyst is described in US Pat. No. 6,057,034 (incorporated herein by reference in its entirety).

  In one embodiment, the substrate is suitable for use in a catalytic converter configured inside the engine head in front of the exhaust manifold in connection with the exhaust gas flow.

  Additional embodiments of the catalyst substrate include catalyst substrates comprising nSiRF-C having the approximate attributes shown in the table below.

  Another specific embodiment is a catalytic group comprising a catalyst substrate comprising nSiRF-C as described in Table 1; and a catalyst selected from the group consisting of palladium, platinum, rhodium, derivatives thereof and combinations thereof. Directed to the material.

  Preferred substrates comprising high-grade nonwoven refractory fibers have a porosity of 90% to 98% and an emissivity value of 0.8 to 1.0.

  In one embodiment, the filtration substrate of the present invention comprises or consists essentially of nSiRF-C, and further includes a front surface inlet end and outlet end, thin, porous intersecting and vertically extending walls and Including horizontally extending walls (which define a plurality of grooves extending substantially longitudinally and parallel to each other between the front surface inlet end and the outlet end); It includes a first section of cells that are clogged along a portion of its length with stripes, and a second section of cells that are clogged with board stripes, and the first section of non-board stripe clogged cells is a board Smaller than the second section of the striped clogged cell. Such a configuration is further described in US Pat. No. 6,057,036 (incorporated herein by reference in its entirety). Up to three quarters of the cells in the first section cannot be clogged. Or up to half of the cells in the first section cannot be clogged. Or up to a quarter of the cells in the first section cannot be clogged.

  It is further understood that the present invention consists of, or is directed to, embodiments consisting essentially of limitations of various embodiments. Thus, for example, if one embodiment is described as a catalyst substrate comprising nSiRF-C and a catalyst, the present invention further includes a catalyst substrate consisting of or consisting essentially of nSiRF-C and a catalyst. Understood.

Catalytic Method of Reaction and Filtration Method Another aspect of the present invention is a catalytic method of reaction, providing the catalyst substrate of the present invention; and a catalyst substrate at a temperature sufficient to catalyze the above reaction. Directed to a method comprising directing fluid flow over and / or through a catalyst substrate. Preferably the reaction converts pollutants to non-pollutants. For example, the catalyst substrate in one embodiment converts carbon monoxide to carbon dioxide.

  The catalytic process is carried out using a substrate comprising an alumina reinforced insulation as described herein.

  In a preferred embodiment, the substrate contains a suitable catalyst.

  In one embodiment, the present invention is an exhaust gas filtration method, providing a filtration or catalyst substrate of the present invention as described above, and directing a flow of fluid, eg, gas or liquid, through the substrate. In which case the gas is directed to a process containing particulate matter.

  In another embodiment, the method further includes burning out the filtered particulate material. Burning out the filtered particulate matter converts the accumulated particulate matter primarily into non-contaminating materials.

  This aspect of the invention is a specific use in diesel engines. In another aspect, the present invention is directed to a filtration method, wherein the filtration utilizes a diesel particulate filter.

  Diesel engines (in this case, compression alone ignite fuel) have been under global surveillance in recent years for their exhaust emissions, which contain many harmful particles in addition to toxic gases. The manufacturer's reaction was to apply known catalytic converter technology to diesel engines. Unfortunately, regulations on emission standards have exceeded the physical and economic limits of conventional catalytic converters. Diesel exhaust differs from gasoline exhaust in that a greater amount of particulate matter is produced. For this reason, current technologies for exhaust emission capture, combustion and oxidation will not fully meet the most stringent emission standards.

  Most buses are manufactured or retrofitted with 85% efficient diesel particle traps [“DPT”]. DPT has high cost, is very complicated, has low fuel consumption, and has low durability. Furthermore, regulations require 100% compliance by 2010, and DPT alone cannot meet these regulatory requirements. The high temperature of the engine or exhaust gas causes the particulate matter to burn with a shorter residence time. Moving the filter closer to the engine's combustion chamber or adding an auxiliary heat source can provide increased heat. Therefore, what is needed is (1) extremely high temperatures, such as near the combustion chamber, ie above 500 ° C .; (2) more resistant to vibrational decomposition; and (3) particulate matter combustion A filter that still retains or improves its action. The ability to achieve particulate combustion even without a catalyst will also provide significant savings regarding catalyst and coating costs.

  Once the filter captures particulate matter (eg, soot), the particulate matter needs to be completely combusted by raising its temperature sufficiently in the presence of oxygen. Combustion of particulate matter can be accomplished by utilizing the current temperature of the outgoing exhaust and / or providing an auxiliary heat source. The time required to bake particulate matter at this temperature is called the necessary “residence time”, “regeneration time” or “burn-out” period. The shorter residence time of the particles in the substrate holes translates to a reduced occurrence of clogged stacking (this stacking can result in a gas flow back pressure that requires extra energy to operate efficiently. ). Therefore, the shorter the residence time, the better.

  One conventional DPT is illustrated in U.S. Patent No. 6,057,077, which discloses a DPT for collecting particles from exhaust gas emitted from a diesel engine. The DPT filter is composed of a non-woven inorganic filter coated with silicon carbide ceramic and a wire mesh formed therebetween.

  Additional uses of filtration substrates or catalyst substrates include from fluid streams such as dust / soot, smoke, pollen, fluids, bacteria / viruses, odors, oils, volatile organic compounds, liquids, methane, ethylene, and extensive Includes the ability to clean or filter contaminants and impurities, such as various other chemicals, for example those listed as “toxic air pollutants” in 188 of EPA.

  Methods for catalyzing reactions and / or filtering liquids are useful in a number of industries or applications, and are particularly useful for one or more of the following. Aerospace industry; asbestos; asphalt roofing and asphalt processing; automatic light truck (surface coating); benzene waste handling; boat manufacturing; brick and structure application; clay product manufacturing; cellulose product manufacturing; Cellulose ether production; Cellulose food packaging production; Cellophane production; Chromium electroplating; Coke oven: Compression, quenching and battery loading; Coke oven; Combustion turbine; Degreasing organic cleaner; Dry cleaning; Engine test cell / stand; Coating, dyeing; Ferroalloy production; Flexible polyurethane foam; Manufacturing operations; Flexible polyurethane foam production; Friction product production; Gasoline fractionation (Stage 1); General regulations; General MACT; Hazardous waste combustion; P; hydrochloric acid production; industrial, commercial and public boilers; industrial cooling tower process heaters; fused iron and fused steel; ironworks (surface coating); leather finishing operations; lime production; magnetic tape; Loading operation; mercury battery chlor-alkali plant; metal coil (surface coating); metal can (surface coating); metal furniture (surface coating); mineral wool product; other coating production; other metal parts and metal products; Landfill with municipal solid waste; Natural gas transportation and storage; Off-site waste recycling operation; Oil and natural gas production; Organic liquid separation (except gasoline); Paper and other webs (surface coating); Active ingredient production; refinery; pharmaceutical production; phosphate / phosphate fertilizer; plus Polymers and resins; polyether polyol products; polybutadiene rubber; polysulfide rubber; phenolic resins; polyethylene terephthalate; polyvinyl chloride and its copolymers production; Portland cement production; primary aluminum production; primary lead refining; Primary copper; Primary magnesium refining; Printing / publishing; Public processing facility (POTW); Pulp and paper (non-combustible) MACT I; Pulp and paper (non-chemical reaction) MACT III; Pulp and paper (combustion source) MACT II; Pulp Reciprocating internal combustion engine; refractory product production; reinforced plastic composite production; secondary aluminum; secondary lead refining; semiconductor production; ship production and ship repair; field improvement; solvent extraction for vegetable oil production; Hydrochloric acid washing process; taconite iron ore treatment; tetrahydride Robbenzaldehyde production; tire production; wet-formed glass fiber, mat production; wooden construction products; wooden furniture; and wool glass fiber production. Such industries and applications often use fixed emission sources defined by EPA.

  Other suitable uses include filtration processes or catalytic processes in one or more of the following applications. Automotive (dust / smoke, odor, oil filtration, VOC, methane, other chemicals (gaseous, solid or liquid)); water jet (dust / smoke, odor, oil filtration, VOC, methane, other chemicals Substances (gaseous, solid or liquid)); snowmobiles (dust / smoke, odor, oil filtration, VOC, methane, other chemicals (gaseous, solid or liquid)); small engines (dust / solid) Smoke, odor, oil filtration, VOC, methane, other chemicals (gaseous, solid or liquid)); motorcycle (dust / smoke, odor, oil filtration, VOC, methane, other chemicals (gaseous, Solid diesel or liquid)); mobile diesel engines (dust / smoke, odor, VOC, methane, other chemicals (gaseous, solid or liquid)); stationary diesel engines (dust / smoke, odor, OC, methane, other chemicals (gaseous, solid or liquid)); power equipment (dust / smoke, odor, VOC, methane, other chemicals (gaseous, solid or liquid)); purification (VOC, other chemicals (gaseous, solid or liquid)); and chemical and pharmaceutical production (dust / smoke, bacteria / virus, odor, oil filtration, VOC, methane, other chemicals ( Gaseous, solid or liquid).

  In addition, additional catalyst applications and / or filtration applications include the use of substrates according to the present invention in one or more of the following areas. Emissions from agriculture and forest incineration; bakery (dust / smoke, smoke, odor, VOC, other chemicals (gaseous, solid or liquid)); filtration of biomedical liquids; breweries and wineries (odor) Cabin air (car, submarine, space industry, airplane) (dust / smoke, smoke, pollen, bacteria / virus, odor, VOC, other chemicals (gaseous, solid or liquid)); Soot / smoke, smoke, pollen, bacteria / virus, odor, oil, VOC, methane, other chemicals); emissions from commercial combustion (odor, VOC, other chemicals (gaseous, solid or liquid) )); Commercially toxic organic emissions; Dry cleaner (VOC, other chemicals (gaseous, solid or liquid)); Evaporating gas (fuel evaporation control, etc.); Fireplace); Cooking (fast food) ( Soot / smoke, , Odor, VOC, other chemicals (gaseous, solid or liquid)); fitness center); general liquid filtration (drinking water treatment)); food processing and food storage (odor, other chemicals (gas) , Solid or liquid)); foundry (odor); fuel cell (VOC, methane, other chemicals (gaseous, solid or liquid)); gas mask (dust / smoke, smoke, pollen, Bacteria / virus, odor, VOC, other chemicals (gaseous, solid or liquid)); VOC applications for general processing / manufacturing (wood products, coating industry, textile industry, etc.); glass / ceramics; greenhouse Electrical appliances for home appliances-Cooling (rechargeable appliances) (odor, oil, VOC, other chemicals (gaseous, solid or liquid)); Electrical appliances for household appliances-Heating (water heaters and household appliances for household use) ) (Odor, oil, VOC, etc. Chemicals (gaseous, solid or liquid)); HVAC public health); Hydrogen reforming (VOC, methane, other chemicals (gaseous, solid or liquid)); Medical growth media; Office buildings Oil / gasoline transport; other electromagnetic insulation (electromagnetic shielding); paint use; gas station (odor, VOC); polymer treatment (odor, VOC, other chemicals (gaseous, solid or liquid)) Recovery of precious metals / catalysts from hot gases and liquids; restaurant vapors; sewage and biological waste (bacteria / viruses, odors, VOCs, methane, other chemicals (gaseous, solid or liquid) ); Slaughterhouse; smokehouse (dust / smoke, smoke); soundproofing material; swimming pool; tanning salon; tunnel and parking (dust / smoke, odor, VOC, methane, other chemicals (gaseous, solid) Or liquid))); and Waste incineration (dust / smoke, odor, VOC, other chemicals (gaseous, solid or liquid)).

Method for Preparing a Catalyst Substrate or Filtration Substrate In another aspect, the present invention is directed to a method for preparing any one of the substrates (catalyst or filtration) as described herein. The present invention is also directed to a method for preparing the catalyst substrate of the present invention. In another aspect, the present invention is directed to a method for preparing a diesel particulate filter. A number of methods, such as those described below, can be used to prepare the substrate.

  In one aspect of the invention, a catalyst substrate as described herein can be prepared using a commercial billet of nSiRF-C. A commercial billet of nSiRF-C is machined to the appropriate shape, form and size. The substrate of the present invention can be prepared as a large brick of a suitable substrate material by machining the brick into a shape suitable for use in the present invention. The coarse mass is easily cut or ground into a preformed shape and then sanded, turned or machined to the final desired shape “slag”. The composition of the substrate material is very resilient to chemistry, heat, temperature and vibrational impact, but the hardness in the substrate material is low. This low hardness allows machining with little or no resistance or durability to the tool. Despite the fact that the mass has a low hardness and is soft, it is very durable and easy to machine, engrave, or shape. For example, in one embodiment, the substrate material is on the Mohs hardness scale, typically 0.5-1.0 (or 1-22 on a Knoop hardness scale), and talc is 1 (Knoop hardness 1-22). ) Is the softest and diamond is the hardest at 10 (Knoop hardness 8,000-8,500). Certain other prior art substrate materials with suitable values are harder. For example, silicon carbide has a Mohs hardness of 9 to 10 (Knoop hardness of 2,000 to 2,950).

  Billets are shaped, sanded, turned, or machined with reduced work compared to certain conventional substrates, such as cordierite, to provide unrestricted shaping capabilities for slag molding. Machining is commonly used for turning cylinders on lathes, shaping with keyhole saws, band saws or thread saws, sanding contours or smoothing surfaces, or other solid materials And can range up to any other machining method known in the art. Billets can be machined to very tight tolerances with the same precision as machining metal, wood or plastic. If the billet is cast in a cylindrical mold having the desired diameter of the final shape, machining simply requires cutting the cylindrical billet to the desired thickness and sanding. This process also reduces substrate loss due to excessive machining and speeds up the process implementation as well.

  In some embodiments, the front surface shape of the substrate is a circle 510, an ellipse 520, and a racetrack shape 530, as shown in FIG. As will be readily appreciated, the shape does not have to be accurate. In three dimensions, the substrate can be in the form of a cylinder or a substantially flat disk. Designs with square corners are not effective in certain applications. Although easy to machine, square or angular designs have proven to be traps for rust and corrosion, such as road salt. Accordingly, rounded corners are preferred in the front surface shape of the slag in certain embodiments.

  The billet can be shaped by a band saw, yarn saw, CNC, or other method known to those skilled in the art. The billet can be further shaped by hand rubbing, lathe sanding, belt sanding, or orbital sanding. The suspended particles are preferably vacuumed to prevent clogging of the material pores. In addition, these particles enter the bearing of the drilling machine, break it, grind it, and streak the bearing. Ceramic dust is also very fine and can be easily sucked by the driver.

  In another embodiment, the present invention provides a method for preparing a catalyst substrate or filtration substrate of the present invention comprising preparing a billet of nSiRF-C composite; and optionally machining the billet to The present invention is directed to a method comprising molding a substrate of the invention. If the billet is prepared in a shape suitable for use in one or more processes of the present invention, the billet need not necessarily be machined into a different shape. In this case, the billet is prepared using the following mold having an appropriate shape. Alternatively, the billet or substrate can be machined into a suitable shape. In addition, a plurality of grooves are machined into the substrate, as described in more detail below.

  The step of preparing the billet (or substrate) includes known methods for preparing these materials. Any known method of preparing a suitable billet or substrate can be used. For example, suitable methods are disclosed in US Pat.

By way of non-limiting example, in one embodiment, preparing a suitable substrate includes the following steps:
Heating a plurality of refractory silica fibers, refractory alumina fibers, and refractory aluminoborosilicate fibers;
Mixing the fibers;
Washing the fibers;
Optionally cutting the fiber into one or more lengths;
Blending or mixing the cut fibers into the slurry;
A step of adjusting the viscosity of the slurry, preferably by adding a thickener;
Adding a dispersant;
Adding the slurry to the mold;
Removing water from the slurry, thereby forming a green billet;
Removing the green billet from the mold;
Drying the green billet in a furnace, preferably at a temperature of about 250 ° F. to about 500 ° F .; and preferably, the green billet in the furnace at about 2,000-2,500 ° F. Preferably pre-warming and incremental heating.

  As mentioned above, the billet is then optionally machined to form the substrate of the present invention.

  In another embodiment, the method further includes machining a plurality of grooves in the substrate.

  In another embodiment, the present invention further includes adding a washcoat to the substrate.

  In another embodiment, the present invention further includes adding a catalyst coating to the substrate.

  In another embodiment, the method further comprises:

  In a further embodiment, fiber mixing is performed after washing and heating the fibers.

In a further embodiment, boron nitride is used in the method of manufacturing a substrate of the present invention. BN → B + N ₂ .

  In a further embodiment, a thickener is used. Preferably the thickener and dispersant used in the process are substantially removed from the substrate during the heating step. For example, thickeners and dispersants can be burned during the sintering process.

  The substrate 2510 is derived from a billet made by cutting and / or forming a rigid configuration of non-woven inorganic fibers and binder. The billet is machined or crafted to the desired external dimensions for the substrate 2510. The inside of the substrate 2510 is then machined or crafted to provide the desired surface area enhancing configuration, such as grooves, washcoats or catalysts. The durable inorganic curable coating 2511 may be applied to the substrate 2510 by brushing, spraying, dipping, or any other common application method. Further, the substrate 2510 can include an oxidation or reduction catalyst applied by brushing, spraying, dipping or any other common application method.

  In one embodiment, the catalyst substrate or filtration substrate of the present invention comprises nSiRF-C and silicon dioxide powder in an amount of 23.0-44.0% by weight, in an amount of 25.0-45.0% by weight. Colloidal silicon dioxide, water in an amount of 19.0 to 39.0% by weight and 1 selected from silicon tetraboride, silicon hexaboride, silicon carbide, molybdenum silicide, tungsten silicide and zirconium diboride And a coating agent having a mixture of two or more radioactive agents. Here, the protective coating agent has a solid component content of 45 to 55% by weight, and such a coating agent is disclosed in Patent Document 40.

The present invention utilizes a plurality of non-woven sintered high grade inorganic refractory fibers, such as present in AETB. Other suitable materials for use as the nSiRF-C of the present invention include AETB-12 (about 20% Al ₂ O ₃ , about 12% NEXTEL® fiber (14% B ₂ O ₃ , 72% Al ₂ O ₃ , 14% SiO ₂ ) and about 68% SiO ₂ ), AETB-8 (about 20% Al ₂ O ₃ , about 12% NEXTEL® fibers (14% B ₂ O ₃ , 72% Al ₂ O ₃ , 14% SiO ₂ ) and 68% SiO ₂ composition), FRCI-12 (about 78 wt% silica (SiO ₂ ) and about 22 wt% aluminoborosilicate (62% Al ₂ O _{3, 24% SiO 2, 14} % B 2 O 3) having the composition) and FRCI-20 (about 78 wt% silica (SiO ₂₎ and approximately 22 wt% of aluminoborosilicate (62% Al ₂ O ₃ , 24% SiO ₂ , 14% B ₂ O ₃ )).

  In a preferred embodiment, the constituents of the inorganic fibers consist or consist essentially of fibrous silica, alumina fibers and aluminoborosilicate fibers. In this embodiment, the fibrous silica contains about 50-90 percent (%) of the inorganic fiber mixture, the alumina fiber contains about 5-50 percent (%) of the inorganic fiber, and the aluminoborosilicate is the inorganic fiber. Contains about 10-25 percent (%) of the mixture. The fibers used to prepare the substrate of the present invention may have both a crystalline phase and a glass phase in certain embodiments.

Preferably, other suitable fibers are aluminum oxide in the range of about 55 to about 75% by weight, silicon oxide in the range of greater than 0 and less than about 45% by weight (preferably greater than 0 and less than 44% by weight). And aluminoborosilicate fibers with boron oxide in the range greater than 0 and less than 25% by weight (preferably about 1 to about 5% by weight) (the oxygen of each of Al ₂ O ₃ , SiO ₂ and B ₂ O ₃ Calculated by the theoretical value of the base). The aluminoborosilicate fibers are preferably at least 50% by weight of crystals, more preferably at least 75% by weight and most preferably about 100% by weight of crystals (so-called crystal fibers). Standard size aluminoborosilicates are commercially available, for example, “NEXTEL 312” and “NEXTEL 440” from 3M Company, which are trade indications. In addition, suitable aluminoborosilicate fibers can be made, for example, as disclosed by US Pat.

  Further suitable fibers include aluminosilicate fibers, which are generally crystalline, but in the range of about 67 to about 77 wt% (eg, 69, 71, 73 and 75 wt%) aluminum oxide and about Contains silicon oxide in the range of 33 to about 23% by weight (eg, 31, 29, 27 and 25% by weight). The standard size aluminosilicate is commercially available, for example, as “NEXTEL 550” from 3M Company, which is a trade designation. In addition, suitable aluminosilicate fibers can be made, for example, as disclosed by US Pat. No. 6,057,097, the disclosure of which is hereby incorporated by reference.

In another embodiment, the fibers used to prepare the substrate of the present invention have α ₂ Al ₃ O ₃ and / or SiO ₂ added to Y ₂ O ₃ and ZrO ₂ added α. -Al ₂ O ₃ is included (forms α-Al ₂ O ₃ / mullite).

  A variety of specific materials can be used to prepare the catalyst substrate. In one embodiment, the material used to prepare the substrate of the present invention comprises, consists of, or consists essentially of refractory silica fibers and refractory aluminum borosilicate fibers. In another embodiment, the material used to prepare the catalyst substrate comprises refractory silica fibers, heat resistant grade alumina fibers and a binder, preferably boron oxide or boron nitride powder.

  In one embodiment, the catalytic substrate of the present invention comprises, consists of, or consists essentially of alumina reinforced thermal insulation (“AETB”) material or similar materials known to those skilled in the art. AETB materials are known in the art and are described in more detail in Non-Patent Document 12 and Non-Patent Document 13, both of which are incorporated herein by reference.

  In another embodiment, the catalyst substrate comprises ceramic tiles (eg, alumina reinforced thermal insulation (AETB)) with a reinforced unipiece fibrous insulation (TUFI) and / or a reaction-cured glass (RCG) coating. Such materials are known in the art.

  Another suitable material is a fibrous refractory ceramic insulation (FRCI). In one embodiment, AETB is made from alumina boria silica (also known as alumina-boria-silica, aluminoborosilicate, and aluminoborosilicate) fibers, silica fibers, and alumina fibers. One generally known application for AETB is as an external tile on the space shuttle, which is ideal for shuttle reentry. AETB has a high melting point, low thermal conductivity and low coefficient of thermal expansion, ability to withstand thermal and vibration shock, low density, and very high porosity and permeability.

In one embodiment, the first component of AETB is alumina fiber. In the preferred case of the present invention, the alumina (Al ₂ O ₃ or aluminum oxide (eg, SAFFIL)) is typically about 95 to about 97 wt% alumina and about 3 to about 5 wt% silica in commercial form. is there. In other embodiments, alumina having a lower purity (eg, 90%, 92% and 94% purity) is also useful. In other embodiments, alumina with higher purity is also useful. Alumina can also be produced by extrusion or spinning. First, a solution of precursor species is prepared. A slow, gradual polymerization process is initiated, for example, by manipulation of pH, whereby individual precursor molecules combine to form larger molecules. As this process proceeds, the average molecular weight / size increases, thereby increasing the viscosity of the solution over time. At a viscosity of about 10 mPa · s (centipoise), the solution becomes slightly tacky and allows the fiber to be drawn or spun. In this state, the fiber is also extruded through the die. In some embodiments, the average fiber diameter is about 1-6 μm (microns), although larger diameter fibers and smaller diameter fibers are also suitable for the present invention.

In one embodiment, the second component of AETB is silica fiber. Silica (SiO ₂ , eg Q-fiber or quartz fiber), in some embodiments, contains more than 99.5% amorphous silica with very low levels of impurities. Low purity (eg, 90%, 95% and 97%) silica is also useful in the present invention. In some embodiments, low density (eg, 2.1-2.2 g / cm ³ ), high fire resistance (1,600 ° C.), low thermal conductivity (about 0.1 W / m-K) and near zero heat. Amorphous silica having an expansion coefficient is used.

In one embodiment, the third component of AETB is alumina boria silica fiber. In some cases, alumina boria silica fibers (3Al ₂ O ₃ .2SiO ₂ .B ₂ O ₃ (eg, NEXTEL 312)) are typically 62.5 wt% alumina, 24.5 wt% silica, and 13 wt%. % Boria. Of course, the exact proportions of the components of alumina boria silica can vary. It is largely an amorphous material, but can contain crystalline mullite. Suitable alumina boria silica fibers and methods for their production are disclosed, for example, in US Pat.

Other suitable materials for use as the nSiRF-C of the present invention include AETB-12 (about 20% Al ₂ O ₃ , about 12% NEXTEL® fiber (14% B ₂ O ₃ , 72% Al ₂ O ₃ , 14% SiO ₂ ) and about 68% SiO ₂ ), AETB-8 (about 20% Al ₂ O ₃ , about 12% NEXTEL® fibers (14% B ₂ O ₃ , 72% Al ₂ O ₃ , 14% SiO ₂ ) and 68% SiO ₂ composition), FRCI-12 (about 78 wt% silica (SiO ₂ ) and about 22 wt% aluminoborosilicate (62% Al ₂ O _{3, 24% SiO 2, 14} % B 2 O 3) having the composition) and FRCI-20 (about 78 wt% silica (SiO ₂₎ and approximately 22 wt% of aluminoborosilicate (62% Al ₂ O ₃ , 24% SiO ₂ , 14% B ₂ O ₃ )).

  In a preferred embodiment, the constituents of inorganic fibers consist of or consist essentially of fibrous silica, alumina fibers and aluminoborosilicate fibers. In this embodiment, the fibrous silica comprises about 50-90% (percent) of the inorganic fiber mixture, the alumina fiber comprises about 5-50% (percent) of the inorganic fiber mixture, and the alumina borosilicate fiber is It constitutes about 10-25% (percent) of the inorganic fiber mixture.

  Fibers similar to those of AETB as described herein may be utilized in addition to or instead of AETB fibers.

  Fiber production by melting can be carried out in two general ways. The first method involves a combination of centrifugal spinning and gas damping. A glass stream of appropriate viscosity constantly flows from the furnace onto a spinner plate that rotates at thousands of revolutions / minute. Centrifugal force ejects glass outward from a spinner wall containing thousands of holes. The glass passes through the hole, is again driven by centrifugal force, and is attenuated by a blow of heated gas before being collected.

  In the second melting technique, the molten gas is supplied to a heated tank, whose bottom surface is perforated with hundreds or thousands of holes, depending on the application. The glass flows through these holes and is drawn to form individual fibers. The fibers are merged into a string and collected on a mandrel.

  In one embodiment, the AETB fiber mixture in the slurry preferably includes three components (eg, glass fiber, alumina fiber and alumina boria silica fiber). Fibrous silica comprises about 50 to 90 percent of the inorganic fiber mixture, alumina fibers comprise about 5 to 50 percent of the inorganic fiber mixture, and alumina boria silica comprises about 10 to 25 percent of the inorganic fiber mixture. . In other embodiments, the slurry comprises any mixture of fibers that can be used to produce a substrate of the invention as described above.

In a preferred embodiment, the fibrous component of the substrate is a mixture of 64% amorphous silica, 21% alumina, and 15% alumina boria silica fibers, and the looseness in the slurry before or during injection molding. With trace amounts of surfactant (e.g. 0.3-1.0 mg / m < ² >) used to help disperse the bulk fiber.

  In one embodiment, the fibers in the slurry are primarily inorganic fibers only. Preferably, in one embodiment, the present invention does not use any carbon to form the substrate.

  Alumina-zirconia fibers can be added to the inorganic fiber mixture as a fourth component or a component that replaces other fibers.

Fiber Mixing In one step of one embodiment of the present invention, the fibers are mixed. Any number of known fiber mixing methods can be used to mix the fibers. One example is high shear mixing that can be used.

Fiber heating In one step of the invention, the fibers are heated according to known methods. The fiber is first heated to chop the fiber more uniformly. The heat treated fibers are washed to remove all dust, shredded debris and loose particles and leave the fibers alone for processing.

  In a preferred embodiment, the fiber is heat purified.

Fiber washing In one step of the invention, the fibers are washed. In a preferred embodiment, the fibers are washed so that the fibers are substantially free of dust and particles. In one embodiment, the silica fibers are washed in acid to remove impurities, rinsed, dried, and then heat treated to provide structural integrity.

Fiber Cutting In another process of the present invention, the fiber is chopped. Fibers for use in the present invention are generally obtained as loose or chopped fibers. Fiber cutting methods are known in the art. Most methods are continuous processes that can handle multiple fibers or strings simultaneously. In general, the product is fed between a set of rotating wheels or drums, one of which supports regularly spaced cutting blades. As the fiber is drawn through the cutter, it is cut to a specific length. Although specific manufacturing details still result in blanks from cut fibers, ownership remains unresolved, but the art generally involves one of two production mechanisms: melting and sol-gel . Preferably the fibers are heat treated before final cutting.

  Preferably the fibers are then cut to a certain size. Suitable lengths of fiber include about 2.54, 5.08, 7.62, 10.16, 12.70 or 15.24 mm (about 0.1, 0.2, 0.3, 0.4 , 0.5 or 0.6 inches), but is not limited to these. Other suitable lengths include 3.175 mm (1/8 inch), 6.35 mm (1/4 inch), and 12.7 mm (1/2 inch). The fibers are preferably relatively uniform in size. In another embodiment, the fibers comprising the catalyst substrate or filtration substrate have an average length of ¼ inch (about 1/100 meter) and a diameter of about 1 to 12 μm (microns), Alternatively, it is 1 to 6 or 10 to 12 μm (micron), and the median fiber diameter is 3 μm (micron). In preferred embodiments, particulate material is not added as it can clog the pore space. Suitable fibers for use in the present invention are commercially available, for example from 3M. Of course, in other embodiments, longer fibers are used.

Slurry In another step of the method of the present invention, a slurry containing fibers is prepared. Rather than extruding a ceramic or wrapping a thread or fabric around a through tube, the substrate is made by a common sol-gel process. This first draws a well-mixed sol of inorganic fibers and colloidal solution into a sol blank or a fiber mold making a green billet or billet (by vacuum or gravity drawing).

  Alternatively, a squeeze casting pressurization method (in this case the pressure is reduced to a negative value) or a vacuum method can be used. The vacuum method forms an inorganic fiber blank with ultra-low density while maintaining its strength. The sol-gel method is used in conjunction with the pressure method or vacuum method to help produce exceptionally low density, which is very beneficial for particle filtration.

  The fibers are blended together in a slurry. In some embodiments, the slurry may contain 1-2% by weight solids, but is almost a fluid such as water. Alternatively, the slurry can contain about 0.5 to about 5 weight percent solids. Other weight percentages are equally acceptable as is known in the art.

  The cut fibers are mixed together in the slurry using a high shear mixer. Deionized water is preferably used in the slurry to avoid impurities that can act to dissolve or destabilize the fiber during use. In one embodiment, the slurry can be pumped with a centrifugal cyclone to remove shot glass and other contaminants (eg, high sodium compound particles).

  Alternatively, organic fibers or particles can be added to the fiber slurry in a proportion of up to 30% by weight. During the combustion phase of manufacture, organic fibers are volatilized or burned out of the product. Burning the fiber leaves a void that creates a path for the gas to escape. By changing the type and proportion of the polymer fibers, the permeability of the tile is adapted. Blanks made by this method are porous and thus allow active cooling by the introduction of discharge air.

Viscosity Adjustment In another embodiment, the viscosity is adjusted to an appropriate range. Higher viscosities prevent the fibers from “laying down” (ie, being laid flat or becoming oriented only substantially in the horizontal direction). Boron nitride can be added as a thickener to coat the fiber during preparation for high strength sintering. In one embodiment of the invention, boron nitride is added and alumina boria silica fibers are not utilized in the slurry.

Dispersant Addition In one embodiment, the method includes adding one or more dispersants to the mixture or slurry.

  In one embodiment of the present invention, one or more surfactants are added to the slurry during the process of the present invention. Surfactants are used in amounts of about 5 to about 10% by weight. Surfactants are used to help disperse the loose fibers in the slurry before or during casting to prevent the fibers from being bundled together.

  In one embodiment of the invention, one or more catalysts as described above are added to the slurry. The addition of the catalyst at this stage of the process creates a substrate having the catalyst impregnated within the porous material. In one embodiment, this configuration eliminates the need for further wash coating or catalyst treatment.

Molding In one embodiment, the slurry is poured into a mold to form a billet. The shape of the mold can take any desired shape. In some embodiments, the shape of the mold results in a substrate having a shape suitable for use in a catalytic converter or particle filter. For example, the mold can be cylindrical in shape. Alternatively, the mold has a pentagonal shape. Preferably the slurry cannot settle in the mold because the fibers can lay down. In one embodiment, vacuum suction is used to keep the fibers settling and maintain the uniform porosity and density of the material throughout the billet. The vacuum suction technique can be used with any number of instructions to control fiber alignment and density for the green billet.

As an example, a billet of catalyst or filtration substrate material is rounded corners 609.6 mm (24 inches) × 609.6 mm (24 inches) (371.612 mm ² (576 in ² )) × 101. Made in a 6 mm (4 inch) mold. Of course, billets with larger or smaller sizes can be made.

Mold materials are stable in water, examples include but are not limited to metals or plastics. Other suitable materials include aluminum, PLEXIGLAS, and other synthetic materials. Aluminum is very durable for a long time, while PLEXIGLAS material is inexpensive and easy to machine. Suitable permeable surfaces are available in the form of fine metal mesh screens. A semi-permeable surface greater than about 32.258 mm ² (about 50 in ² ), under certain conditions, preferably uses a backing or support structure to prevent sagging.

  There are embodiments in which an anaerobic (ie, oxygen-free) environment is desirable during injection molding. Anoxic atmosphere creates an environment that minimizes metal oxidation and uniquely strengthens fiber bonds. The immersion billet is placed in a small chamber (for example, a large plastic bag) filled with ammonia gas. Ammonia is most commonly used because of its low cost and low availability. Nitrogen gas and / or hydrogen gas may also be introduced. Since hydrogen is volatile, nitrogen is preferred over hydrogen. In fact, any gas can be introduced as long as the reducing and oxygen-free environment is maintained. Preferably the gas is provided at a constant flow rate until the immersed sol billet forms a gel billet. At that point, the gas is turned off and the gel billet is exposed to open air, causing the gas to escape.

  Carbon or organic shaped bodies can be used as hole-forming rods that are introduced into the green billet during the molding stage. During high temperature sintering, these rods can collapse, leaving behind the desired plurality of grooves.

Slurry Dehydration In one embodiment of billet manufacture, the slurry is placed in a closed mold that is adjustable in at least one dimension and is at least one wall semi-permeable. The compressive force is applied through an adjustable wall and water is extruded from the slurry through a semi-permeable wall where the fibers gather and become felt. Compression continues until the desired preform (ie billet size) is achieved. This method is generally limited to simple geometric shapes such as blocks or cylinders.

  Gravity is generally not a sufficient driving force and therefore requires the use of a vacuum pump. Vacuum pumps use very little or no pressure. In some cases, vacuum is used to dehydrate, but the use of suction is very slight. Vacuum is used as a means to accelerate the drying process, with great sensitivity to avoid increased density. Preferably only mild vacuum assistance is used.

  More complex shaped billets can be prepared, for example, by alternative methods in which a slurry head is placed and held on a semi-permeable mold form. A low pressure is established outside the permeable form by a vacuum pump. The differential pressure moves the water through the permeable form where the fibers are collected and felted. The differential pressure is sustained until the desired thickness is achieved. This process is advantageous for applications where the desired substrate is highly curved, since the billets can be made in a generally reticulated shape or close to their final form.

  Multiple (two or more) slurry recipe injections or mixings, as well as changes in tensile vacuum rate (multiple hours) may result in several areas that are denser than others and / or areas of different physical properties A billet is provided. Billets can have incremental or different layers or cores with different chemical compositions and densities. The billet has one or more zones, each of which has a unique shape, position and physical properties as required. Each band is where it is necessary to change strength, thermal or electrical conductivity, catalyst adhesion capacity, thermal expansion, vibration or thermal shock, weight, porosity and permeability, sound attenuation, or any other preferred property It can change.

  By using different slurry recipes and molding techniques, the billet can also be layered. In addition, billets are not limited to parallel plane layers (eg, layers on cake), but billets are horizontal layers, angled layers, spherical layers, pyramidal and free-form layers, or known in the art. It can be formed using any other configuration. It should also be noted that the billet density can be changed chemically and physically as desired during this process.

  A billet can also be formed by configuring multiple billets of different chemistry in any configuration, whether or not cured inside or inside another billet. The core billet can be manually placed or injected into the core. The result is a core or cores with some density. Since it is a combination of core layering, the shape or form of these cores and billets is not limited. The core may even be made inside the core. The process is repeated an unlimited number of times as needed to produce a unique number of billet combinations in an unlimited shape.

Drying the green billet In one step of one embodiment, the slurry in the mold is oven dried for a time sufficient to dehydrate (i.e., expel any water contained in the slurry). Water is discharged by gravity. A slight vacuum assistance may be utilized. Other methods known in the art can of course be used.

Removing the green billet from the mold and drying the green billet In one step of one embodiment of the present invention, the green billet is removed from the mold. Generally, the billet can be removed when it is sufficiently dry to handle. Alternatively, the billet is removed when it is sufficiently dry to be manipulated by the machine.

  For example, when the billet is sufficiently dry to be handled, it is removed from the mold. The billet is then dried in an oven. Sufficient low temperature is used to complete the dehydration process and leave the fibers still in their intended configuration. Most preferably, the temperature is sufficient to dry the billet if necessary, but is insufficient to cause any or substantially any sintering of the billet. In another preferred embodiment, a temperature of about 250-500 ° F. is used in this step. In a further embodiment, the billet is dried at a temperature of about 180 ° C. for about 2 to about 6 hours, preferably about 4 hours. Other times and temperatures known in the art can be used.

The billet then “sucks” (ie, sucks) the binding solution into the billet, so that the dry billet is optionally in a sol-gel binder, preferably an alumina sol-gel binder, known in the art. For example, it is immersed at various temperatures for a period of 2 to 3 days. Suitable binders are known in the art and may be required to impart preformed structural integrity as well as to promote sintering. Billets can utilize single or multiple binder processes to alter the strength and conductivity of the billet. Also, several times the application of the binder increases the strength of the billet but can reduce or plug the pore space. Any suitable binder can be used. The binder can be an oxide binder (eg, SiO ₂ or Al ₂ O ₃ ). The oxide binder can also be a glass configuration, a crystalline configuration, or other inorganic binder. Binders can be applied using known techniques and methods, such as those disclosed in US Pat. No. 6,057,032, which is hereby incorporated by reference.

Drying the green billet (sintering)
In another step of one embodiment of the present invention, the green billet is heat cured. The temperature for heating / curing or sintering is generally higher than the temperature used to dry the green billet. In one embodiment, the temperature is increased incrementally over one or more hours, preferably over several hours, until the desired temperature is reached. In one embodiment, the furnace is pre-warmed and heated incrementally to about 2,000-2,500 ° F. Other temperatures known in the art are also suitable.

  In a preferred embodiment, after gelling the binder, the billet is heated to about 200 ° F. for about 4 hours and then gradually increased to about 600 ° F. over about 5 hours. Is cured. After achieving and holding the maximum temperature, the billet is quenched. The end result is a rigid inorganic fiber billet. Furthermore, the process of thermosetting the blank can vary with the temperature used, the length of time to cure, the quenching temperature and time, the incremental temperature increase, and the incremental temperature increase.

  The billet is burned to provide the energy necessary to sinter the fiber-fiber contact, thereby forming a bond that imparts strength to the substrate. For example, strength can be increased by increasing the number of fiber-fiber contacts. Increasing the number of contacts increases density and bend coefficient. The more the pore network bends, the lower the permeability. Sintering does not melt the fibers together, but instead bonds them chemically. The billet is gradually heated in a high temperature furnace. The billet is pre-warmed and heated incrementally to about 2,000-2,500 ° F. until the desired density and fusion is obtained. Secondary chemicals such as thickeners are burned out in a preferred embodiment. There remains a substrate comprising, or alternatively consisting of, or consisting essentially of sintered fibers.

  In a preferred embodiment, the viscous (thickener) chemical and dispersant are burned out.

  In other embodiments, a number of curing steps are performed. This can be done to increase the hardness of the substrate.

  Variables in the drying and curing process can be adjusted by the desired density, strength, porosity or permeability of the fiber blank, or resistance to high temperatures. In some embodiments, the curing process uses multiple curing applications and can vary the heating and cooling intervals and approaches. The billet can also be rapidly cooled to quench or temper the billet. The slurry may be subjected to additional heating or other treatments such as densified coating or multiple curing and sintering.

Physical Modification In one embodiment of the process, the billet is coated with a catalyst. In one method of applying a catalyst to a substrate, the substrate can be formed from a slurry containing the catalyst. Other suitable methods of applying the catalyst can be used. Another advantage of the present invention is that it has been surprisingly discovered that the catalyst can be applied to nSiRF-C materials using methods that can apply the catalyst to other materials.

  In another embodiment of the invention, the catalyst is added to the slurry prior to shaping. In this case, a catalyst base material in which the catalyst exists directly on the individual fibers constituting the base material is formed. This method of adding the catalyst to the substrate, in certain embodiments, provides an efficient method of dispersing the catalyst in the core of the catalyst substrate, but having no catalyst present along the groove walls. In this embodiment, a washcoat is not necessary.

Machining A billet in the form of a rough block is cut or ground to a specific shape and then sanded, turned or machined to the final desired shape “slag”. The composition of the material is very resilient to chemicals, heat, temperature and vibrational impact, but in a preferred embodiment the hardness is very low. This low hardness allows machining with little or no resistance or durability to the tool. Despite the fact that the billet, in certain embodiments, has low hardness and is soft, it is very durable and easy to machine, sculpt, or shape . Mohs hardness meter, material is usually 0.5-1.0 (or 1-22 Knoop hardness meter), talc is 1 (Knoop hardness 1-22) and softest, and diamond is 10 (Knoop) Hardness is 8,000 to 8,500). For example, silicon carbide has a Mohs hardness of 9 to 10 (Knoop hardness of 2,000 to 2,950). With respect to other known substrates, billets are very soft, such as styrofoam or balsa material, and require no effort to machine or engrave.

  Billets are shaped, sanded, turned, or machined to provide unrestricted shaping capabilities for slag molding. Machining is commonly used for turning a cylinder on a lathe, shaping with a keyhole saw, band saw or yarn saw, sanding the contour or smoothing the surface, or other solid materials and the art Can range up to any other machining method known. Billets can be machined with very close tolerances with the same precision as machining metal, wood or plastic. If the billet is cast in a cylindrical mold having the desired diameter of the final shape, machining simply requires cutting the cylindrical billet to the desired thickness and sanding. This process also reduces substrate loss due to excessive machining and speeds up the process as well.

  As shown in FIG. 5, there are many possible front and back surface shapes, including a circle 510, an ellipse 520, and a racetrack shape 530. In three dimensions, the substrate can be in the form of a cylinder or a substantially flat disk. Conventional substrates exist as one of these three designs. A design with square corners is not effective. Although easy to machine, square or angular designs have proven to be traps for rust and corrosion, such as road salt. Therefore, a rounded corner is preferable in the front surface shape of the slag.

  The billet, substrate, or slag can be shaped by a band saw, yarn saw, CNC, or other methods known to those skilled in the art. The slag can also be shaped by hand rubbing, lathe sander finish, belt sander finish, or orbital sander finish. Airborne particles must be vacuumed away to prevent clogging of material pores. In addition, these particles enter the bearing of the drilling machine, break it, grind it, and streak the bearing. Ceramic dust is also very fine and can be easily sucked by an operator.

  The modeling slag is used as a base material in the present invention. The surface area of the substrate is an important attribute for catalyst applications. The surface area is the total amount of surface that must pass through as exhaust exhaust moves through the exhaust filter. The surface area increase translates into a surface increase where chemical reactions occur between contaminants and the catalyst and thermal processes, making the catalytic converter process faster and more efficient. Speed and efficiency produce little or no clogging that can cause exhaust system failure.

  In one embodiment, the substrate of the present invention has a total surface area of 83.58 square inches / cubic inch. This translates to a larger area that can be impregnated with noble metals compared to cordierite samples with comparable macro dimensions (eg diameter, length and width). However, it should be noted that this total surface area calculation does not uniformly include the density, porosity and permeability of different materials.

  In an exemplary embodiment of the invention, the substrate is used in an exhaust filter system for a diesel engine. The substrate is made using an AETB formulation and is formed into billets of about 13 inches × 13 inches × 5 inches having a density of 8-25 pounds / cubic foot. From the billet, a 5 inch tall cylindrical slag (6 inches in diameter) or an elliptical slag is cut from the billet with a diamond on the tip or a tungsten carbide band saw. This slag is further machined to precise tolerances on a rotating lathe (for right cylinders) or with a belt grinder to form a substrate.

Preparation of Holes and Grooves in the Substrate In one embodiment of the present invention, a plurality of grooves are formed in the filtered or catalytic substrate substantially longitudinally with respect to the intended gas flow. The groove extends partially or entirely through the length of the substrate. 5-14 show schematic diagrams illustrating certain embodiments of the present invention having a plurality of grooves. In some embodiments, the groove extends at an angle to the fluid flow.

  The inner surface of these grooves can be chemically coated to capture and treat more contaminants in a small volume of substrate. When grooves are formed in the substrate, in order to retain a high surface area, a smaller diameter, eg, 200, 400, 500, 600, 700, 800, 900, 1,000, 1,100, 1,200. 1,300, 1,400, 1,500, 1,600, 1,700, 1,800, 1,900, 2,000, 2,100, 2,200, 2,300, 2,400 or 2 A small groove with 500 cpsi is preferred.

  In another embodiment, the groove extends through the entire length of the substrate. Such a substrate has a flow-through configuration.

  Alternatively, the groove does not extend through the entire length of the substrate, but extends from about 50% to about 99% through the length of the substrate. Such a substrate is considered a wall flow configuration. The non-perforated portions remaining in the grooves of the wall flow substrate can have various thicknesses. FIG. 8 illustrates a wall flow pattern substrate 820 according to one embodiment of the present invention having non-perforated portions 840 and 845 of varying wall thickness. In this embodiment, the alternating entry grooves have a thicker wall thickness than the other entry grooves as well as the exit grooves. However, the various non-perforated portion thicknesses can be configured in any combination such that the entry or exit groove has a thinner or thicker non-perforated portion, where all non-perforated portions are substantially similar in thickness. But it doesn't have to be. The wall thickness is thin and porous so that the exhaust gas 830 passes from the exhaust entry groove through the wall to the exit groove and traps the exhaust particles. The length between the inner edges 850 and 855 of the non-perforated portion is known as the intersecting region. If the non-perforated portion 840 is thicker in some or all of the entry grooves, the exhaust stream 830 will flow through the substrate groove wall at the intersection region and exit the substrate 820. The exhaust stream 830 still passes through the thinner non-perforated portion 845. In another embodiment of the invention, the non-perforated portion of the groove has a selective impregnation of the catalyst so that the amount of catalyst is different from the amount on the groove wall.

  The thickness of this non-perforated part is limited. The gas flow is increased by increasing the surface area of the wall having an equivalent thickness. If the non-perforated part is too thin, it can burst due to excessive back pressure.

Mechanical drilling Once an embodiment of the substrate is cut from the billet and machined, it can be inserted into a drilling holder for drilling. A plurality of grooves may be drilled in the substrate in a direction substantially parallel to the major axis of the cylinder and the flow of exhaust exhaust. The smaller the groove diameter, the more grooves can fit into the substrate.

  In an alternative embodiment, the groove is drilled in the substrate. The substrate is placed in a metal holder for drilling. The holder can be, for example, a pair of large metal arms that hold the substrate slug securely in place and prevent it from moving while not breaking the substrate. The holder secures the substrate and holds it firmly for drilling. After drilling one side of the substrate, the holder rotates exactly 180 degrees to allow drilling on the opposite side of the substrate. If the rotation is not exactly 180 degrees, the drill grooves will not be properly aligned or parallel. Further, the inlet pressure should be substantially the same as or similar to the outlet pressure. Preferably, to ensure parallel walls, the holder should not move the substrate greater than 0.0001 inches in any undesired direction.

  The substrate grooves of the present invention can be prepared using a mechanical drilling process. In one embodiment, computer numerical control (“CNC”) drilling is used, which is common among machine shops and is the preferred method. CNC drilling is very slow and is not economically feasible in large scale manufacturing environments that require the production of thousands of filters per day. CNC drilling is performed with high precision and accuracy. CNC drilling is performed by creating multiple paths using a drill bit. The CNC drill will drill a bit more in the substrate in each path to remove the fibrous material as the bit comes out.

  The drill bit can be tungsten carbide because of its toughness and brittleness, or it can be a similar material known to those skilled in the art.

  The drill bit penetrates at a feed rate of about 10 feet / minute. A slow feed rate is necessary to prevent the drill bit from melting. As the drill bit penetrates at a feed rate of 25 feet / minute, the drill bit melts. In addition, because of the tremendously large hole space, drill bits have a tendency to “walk around” or move around. Slower penetration speeds eliminate this problem.

  It is preferable to rotate the drill bit at a slow speed. The drill bit should rotate at about 200 revolutions / minute. Rotating the drill bit at a higher speed, for example about 10,000 revolutions / minute, can cause melting of the trillbit. The drill bit is kept cool throughout the drilling with a lubricant such as water, alcohol or glycerin.

  Once the substrate is cut and sanded to the final dimensions, the substrate is grooved or perforated. In this exemplary embodiment, the groove is cut using DPSSL. Since the substrate is very porous and permeable, the substrate need not be as thick as a conventional filter. Furthermore, the thinner or smaller the substrate, the lower the production cost, as cutting one billet produces many substrates and requires a reduction in the amount of any coating or catalyst to be applied.

Wet drilling In another embodiment, wet cutting (or wet drilling) is used to form the grooves. Wet cutting uses a very fine spray of water at very high pressure to make holes in the substrate. However, the water jet cannot be stopped during the cutting process to leave a blind hole (ie a groove that does not pass completely through the substrate). The physical nature of the water jet limits the size of the open groove to a diameter that is not smaller than the diameter of the jet. In some embodiments, a rectangular hole could be made with a jet.

Gas perforation In another aspect of the invention, a substrate is prepared using a gas perforation method. Gas perforation is known in the art and can be applied to the substrate of the present invention to prepare grooves in the substrate.

Combing In another embodiment, the grooves are formed or shaped using a comb process. The comb is preferably a metallic device having a plurality of pawls that can be pushed into the substrate. The comb used for drilling includes a plurality of pawls. The length, width, thickness and shape of the pawl can vary depending on the desired characteristics, configuration and dimensions of the groove.

  In some embodiments, the comb is pushed into the substrate substantially perpendicular to the surface of the substrate. In other embodiments, the comb is pushed into the substrate at an angle to the surface of the substrate. The use of combs is a preferred method, especially for forming blind grooves. It is understood that suitable combs can also be manufactured such that the combs are made from, for example, 4 × 4 or 16 × 16 rows and columns.

  In general, the comb process involves repeatedly pushing the comb into the substrate material multiple times until most or all of the grooves are shaped. This process is referred to herein as pecking. Optionally, the comb can be removed from the groove after each indentation so that excess substrate material can be removed from the groove, for example by air. It is preferred to prevent fiber stacking during the pecking / drilling process. Fiber stacks can rupture the wall or rupture the whole. To take advantage of this property, vacuum and / or compressed air can be used to clean the groove and drill bit surface.

  In one embodiment, the comb is pushed into the substrate with sufficient force to drive or remove an amount of substrate material from the groove wall. In a preferred embodiment, a sufficient amount of force is applied to the comb so that the pawl extends about 0.1 inch into the groove. Other suitable values include 0.05, 0.15 and 0.2. Preferably, the amount of force applied to form or shape the groove is an amount sufficient to form or shape the groove without substantial damage to the groove wall. The process involves repeatedly pushing the pawl into the substrate until the groove is made to the desired length and shape.

  The shape of the pawl dictates the shape of the groove. For example, a rectangular groove with a rectangular groove opening is made using a rectangular pawl on a comb.

  A wedge-shaped pawl on the comb is used to make a wedge-shaped groove. Use of a wedge-shaped pawl results in a groove whose wall is parallel to the square opening. As shown in FIG. 17, substrate 1700 incorporates a parallel wedge-shaped “blind” groove 1702, ie, a groove that does not have an exit hole. Blind groove 1702 allows gas 1704 to pass through the pore space groove wall before exiting.

  A pyramidal groove is made using a four-sided pyramidal pawl on the comb. The walls are parallel and the openings are substantially square. However, since the grooves meet at a single point rather than being adjacent to a wall having a flat front surface, the wall thickness of the groove opening is minimal. This results in a reduction in the front surface area and thus a reduction in back pressure. With a four-sided pyramidal shaped pawl, no wedge shims are required to separate the combs. In this embodiment, referring to FIG. 16, a suitable comb has a pawl that reaches a point rather than having a flat end. Of course, various other shapes of nails are also encompassed by the present invention.

  A tent pawl on the comb is used to make a polygonal groove. The polygonal groove minimizes the front surface area.

  Referring to FIG. 16, the dimensions of an exemplary comb 1600 are shown according to one embodiment of the present invention. Comb 1600 is approximately 6.000 inches long and 0.0308 inches wide. Comb 1600 includes a base 1610 from which a plurality of pawls 1620 extend. The base 1610 has a height of 0.4375. The plurality of pawls 1620 are 1.250 long and 0.0308 wide and are spaced 0.010 inches apart.

  In one embodiment of the comb process, the groove is first formed by a drill bit and is circular. In accordance with one embodiment of the present invention, a comb pawl pierces a circular groove (ie, compression or embossing) to create a shaping groove in order to produce a shaping groove with parallel walls. One embodiment of a comb 1500 is shown in FIG. Preferably the drilling is performed with a CNC press. The shapes left behind are the shaping grooves and the groove openings. The cell wall thickness can vary as described above. In certain embodiments, the combing process produces a catalyst or filtration substrate having a groove wall thickness of about 4 mils to about 20 mils, preferably about 6 mils to about 10 mils.

  In the comb process, a metal comb is placed in a box called a jig and placed on a CNC press for drilling. Within the jig, the combs are separated by wedge shims. The space between the combs is low tolerance and the combs need to be held firmly in the jig to limit movement during drilling. Referring to FIG. 16, wedge shim 1630 is utilized as a spacer for comb 1600. The wedge shim 1630 has dimensions of 0.010 inches wide, 6.000 inches long and 0.4375 inches high.

  Preferably at least one screen is provided on the comb to maintain pawl alignment. Preferably the screen is floating to distribute the alignment as needed. In addition, the screen is useful for pawls of various lengths, for example about 0.5 inches to about 6.0 inches long. At least one screen can be configured anywhere along the pawl, eg, floating, spring-loaded, or fixed. At least one screen may be present floating along the pawl. The pawl is not affixed to at least one screen, but rather the screen is configured on the pawl so that the screen is adjustable. At least one screen may be spring-loaded on the pawl. By springing the screen, the pressure of the substrate against the screen maintains the distance between the pawls at approximately the edge of the substrate. The at least one screen can also be secured to the pawl at any position along the pawl length.

  Another embodiment of the present invention is a process for manufacturing a catalyst substrate or filtration substrate having a plurality of grooves, including using a comb to strike the substrate to form a plurality of grooves. set to target. This process is a stepwise process in the preferred embodiment. That is, the entire groove is not formed by a single insertion of the comb pawl. Rather, the comb pawl is repeatedly inserted and removed in incremental increments until the desired length of the groove is obtained. Preferably, the grooves are cleaned of removed substrate material between each bump or at every other bump.

  In another embodiment, the comb process is an automated process that utilizes a machine and / or robot to form the grooves.

Comb Manufacturing Methods There are many methods of manufacturing combs for use in the present invention. The comb may be made from materials including but not limited to stainless steel, tungsten or key material. Comb modeling methods include the use of laser cutting, wet cutting, and electrodischarge machining, or other modeling methods available to those skilled in the art.

  DPSSL can be used to make combs. Wet cutting can also be used to produce combs. For example, in one embodiment, 30-40 combs are made in a single cut using a wet cutting method.

  Electrodischarge machining (“EDM”) is an alternative method for producing combs. EDM is a thermal corrosion process in which conductive material is removed from a series of repetitive electron discharges between an electrode and a conductive workpiece in the presence of a dielectric fluid. If the substrate is made electrically conductive, EDM can be used on the substrate as well. There are at least two types of EDM: (1) ram and (2) wire.

  Using an EDM ram, or engraving machine, an electrode / tool is attached to the ram, which is connected to one pole, usually the anode, of a pulsed power supply. The workpiece is connected to the cathode. The workpiece is then configured such that a gap exists between the workpiece and the electrode. The gap is then filled with a dielectric fluid. Once the power is turned on, thousands of direct current or DC impulses per second cross the gap and start the corrosion process. The generated spark temperature can range from 14,000 ° F to 21,000 ° F. As corrosion continues, the electrode advances to work while maintaining a constant gap size.

  The wire EDM method is preferred for comb production. The wire method uses a consumable charged wire as an electrode in order to make complex sections as the consumable charged wire moves in a preset pattern around the workpiece.

  If the wall is too thin, any rough edges on the pawl can tear the wall that comes and goes during drilling. Thus, the comb should be polished to remove any curl or sharp edges that can be trapped on the fiber. Comb cutting and polishing generates heat, which can twist the comb. To ensure that the resulting holes are parallel and not ruptured, the tolerance is preferably kept at about 0.0001 inches.

  The comb used for drilling includes a plurality of pawls. The length, width, thickness and shape of the pawl can be varied depending on the desired attributes of the groove. Referring to FIG. 16, the dimensions of the comb 1600 are shown according to one embodiment of the present invention. Comb 1600 is approximately 6.000 inches long and 0.0308 inches wide. Comb 1600 includes a base 1610 from which a plurality of pawls 1620 extend. The base 1610 has a height of 0.4375. The plurality of pawls 1620 are 1.250 long and 0.0308 wide and are spaced 0.010 inches apart.

Laser machining Other methods include diode pumped solid state laser (“DPSSL”) drilling; chemical lasers such as CO ₂ ; electron beam (“EB”) drilling; or electrode drilling machine (“EDM”), or to those skilled in the art Use of other methods of known fields. Any laser suitable for cutting the comb material can be used.

  The substrate can be cut using laser drilling, such as DPSSL drilling. This method drills using a laser programmed using a CAD program. The CAD program is loaded into the CAM program. The laser is cut using a minute pulse of oxygen, or preferably nitrogen. DPSSL makes it possible to cut grooves at a rate of about 2,000 grooves / minute. In one embodiment, the groove has a diameter of about 100 nanometers. Laser drilling can be used using known techniques and methods such as those disclosed in US Pat. No. 6,057,037, the teachings of which are hereby incorporated by reference in their entirety. In one embodiment, the process uses laser drilling to prepare a groove having a depth (or length) of about 0.5 inches or less.

  In one embodiment, the created groove is large enough for particles to enter, but small enough for a large number of particles to be removed from the exhaust gas stream.

  Furthermore, in one embodiment, the substrate material is about 97 porosity, which means that there is a tremendous amount of space for gas to pass through the substrate. This large porosity also provides additional surface area for the particles to deposit on.

1) Measurement of repetition rate at 10 kHz;

2) External triggering (power decay) between 0 and 15,000 Hz. Internal induction from 7,500 Hz to 15,000 Hz. Real Random Firing Mode for external triggering from 0 to 1 000 Hz in all power modes is optional; 3) Gator laser has a closed loop water system for temperature control Use.

  Preferably, the substrate material is substantially free of impurities such as carbon when machined by a laser.

Hole Forming In an alternative embodiment, the substrate of the present invention is prepared with grooves pre-formed in the billet. In this embodiment, the use of a groove forming machine creates a groove in the billet. A groove forming machine is a rod having an appropriate size and shape for forming a desired groove when a green billet is formed.

  Various types of materials can be used for the groove forming machine described above. For example, the grooving machine can be a strong durable material that can withstand the temperature of the drying process, such as a metal or polymer. Once the green or finished billet is formed, the rod is removed, leaving a groove. The groove can be further machined as described above.

  Alternatively, in other embodiments, the rod is made of a material that can evaporate or collapse when exposed to a suitable source of radiation or heat, eg, laser or heat. In another embodiment, the groove forming machine is made from carbon, carbon derivatives and the like.

Specific Embodiments In some embodiments, the grooves are drilled using a computer controlled CNC drill to maintain uniformity, as described below. The drilling process is performed under a constant water shower to prevent the floating of dust that is an OSHA hazardous material and can adhere to and break the drill bearing.

  The perforated substrate is optionally applied with any catalyst after being oven dried to drive out or burn out any water or other liquid that may remain in the pore space. The baking time is not important. Sufficient time is used to remove most or substantially all of the water. Water evaporation can be determined by simply weighing the substrate. The baking time mainly accelerates the dehydration process. After heating the filter element several times at different intervals, the weight decreases uniformly and the substrate is easy to apply any catalyst or coating.

  In a preferred embodiment, the substrate grooves are first prepared by drilling and then shaped using the comb method. Because of the low thermal conductivity of the preferred substrate, when the substrate is drilled, most of the heat generated during the drilling and cutting process is reflected back to the drill bit and escapes from the substrate. For this reason, the drill bit can absorb some heat and expand, overheat and / or melt. Preferably the cooling of the drill bit is preferably carried out with water. In another embodiment, the drill operates at a low drill rate, eg, 200 RPM, to minimize heat generation. Of course, other drill speeds that are faster or slower are also suitable. In another preferred embodiment, the drilling uses a 2 or 4 or 6 face drill with a modified twist and head (drill tip) configuration.

  Further, in a preferred embodiment, the groove is drilled over multiple drilling trials. For example, a groove about 1 inch long can be prepared by drilling into the substrate at a depth of about 0.1 inch at a time until the final length is obtained. The grooves can be cleared from the drilled substrate material between drilling attempts.

Center punch and pilot hole

  Since vacuum scavenging of the cut fibers must be removed, a pecking method is utilized.

  In the preferred embodiment, the blind groove was drilled a section deeper than our intended depth to allow the extra area to be stuffed with fibers during the combing process. The comb is programmed to reach the depth of the indicated wall flow configuration, and the extra space contains any loose substrate material remaining in the groove.

Product by Process In another embodiment, the present invention is directed to a product prepared according to the methods described herein. Specifically, the present invention is directed to a catalyst substrate prepared according to any one of the specific embodiments described herein. In another aspect, the present invention is directed to a filtration substrate prepared in accordance with any one of the specific embodiments described herein.

Applications Various embodiments and applications of the present invention are discussed below. These example applications are given for illustrative purposes only and are not intended to limit the scope of the present invention. Any of the catalyst substrate and filtration substrate embodiments described above can be used in a variety of applications.

Catalytic Converter In another embodiment, the present invention is directed to a catalytic converter comprising the catalytic substrate of the present invention. The catalytic converter of the present invention can be used in an engine exhaust system in a manner similar to that used for known catalytic converters. Of course, the catalytic converter of the present invention has advantages over prior art converters. Because of these advantages, the catalytic converter can be used in a manner where known catalytic converters cannot be used.

  Any of the specific embodiments of the substrate of the present invention as described above are used in one or more specific applications, such as catalytic converters. In a specific embodiment, the catalytic converter comprises a catalyst substrate of the present invention; a mat around the catalyst substrate; and a canister, preferably a metal canister, and optionally further comprises a washcoat, and optionally. .

  Another aspect of the present invention is directed to a converter that includes or is adjacent to an exhaust manifold of an engine exhaust system and that includes the catalytic substrate of the present invention. Such a catalytic converter is called a manifold catalytic converter (in other terms, a manifold-catalyst converter, a manifold converter, etc.). The manifold-catalyst converter of the present invention includes a manifold-catalyst converter known in the art, in which case the catalyst substrate of the present invention is used in place of the substrate of the prior art. Such a manifold-catalyst converter is disclosed in, for example, Patent Document 44 and Patent Document 45.

  In another embodiment, the present invention is directed to an improved catalytic converter, wherein the improvement comprises a novel substrate as described herein. Any one of the specific embodiments of the substrate can be used in the improved catalytic converter.

  In another embodiment, the present invention is an improved catalytic converter for treating internal combustion engine exhaust comprising at least one catalyst adhered to a substrate, a metal oxide washcoat and metal oxide particles, Is directed to a converter comprising a substrate comprising an nSiRF-C composite and a catalytic metal.

  In another embodiment, the present invention is an improved catalytic converter for treating internal combustion engine exhaust comprising at least one catalyst adhered to a substrate, a metal oxide washcoat and metal oxide particles, Is directed to a converter comprising a substrate comprising an nSiRF-C composite and a catalytic metal.

  In another embodiment, the present invention is an improved catalytic converter for treating internal combustion engine exhaust comprising at least one catalyst adhered to a substrate, a metal oxide washcoat and metal oxide particles, Is directed to a converter that includes a substrate comprising an AETB composite.

In another embodiment, the present invention is directed to a manifold-catalytic converter having a catalytic substrate comprising an nSiRF-C composite and a catalyst. A manifold-catalytic converter (sometimes referred to as an underfloor catalytic converter) is partially or entirely placed in the engine head. In one embodiment, the mani-catalytic converter comprises a catalytic substrate of the present invention, wherein the substrate has a density of about 12 lb / ft ³ , a porosity of about 97%, and a low thermal expansion And has high structural integrity and low thermal conductivity. In a preferred embodiment, the mani-catalytic converter has about 600 cpsi and has a wall thickness of about 6 mils. The mani-catalytic converter in this embodiment has a wall flow configuration. In a preferred embodiment, the mani-catalytic converter has a substantially box-shaped (various length through the substrate) groove shape with a substantially square opening (or hole). In a preferred embodiment, the catalyst substrate of the mani-catalytic converter is made using a comb method. Further, in this embodiment, the catalyst substrate includes an alumina washcoat. In this embodiment, the mani-catalytic converter can catalyze both the oxidation and reduction of pollutants, for example, it has a catalyst that can oxidize pollutants and has a catalyst that can reduce pollutants. The cani of the mani-catalytic converter is prepared by swage processing. In a preferred embodiment, the mani-catalytic converter comprises two substrate units. The mani-catalytic converter is used in some embodiments alone or in combination with a pre-catalytic converter. In a preferred embodiment, the mani-catalytic converter includes an expandable mat. The mani-catalytic converter can be used for all internal combustion engines. The mani-catalytic converter can be used with a fuel addition catalyst. Further, the substrate of the mani-catalytic converter can be reinforced.

The main catalytic converter of the present invention as described above is also used in one embodiment with one or more aftertreatment systems. Such post-processing system, NO _x adsorbent, HC adsorbent, SCR systems, and the like.

  Furthermore, an embodiment having the same or similar configuration and attributes as the main catalytic converter described above can be used for the membrane catalyst. A membrane catalyst contains the catalyst base material which has the above film | membrane structures.

In another embodiment, the present invention is directed to a head-catalytic converter having a catalytic substrate comprising an nSiRF-C composite and a catalyst. The head-catalytic converter is located in part or in whole in the engine head. In one embodiment, the head-catalytic converter comprises a catalytic substrate of the present invention, wherein the substrate has a density of about 12 lb / ft ³ , a porosity of about 97%, and a low thermal expansion. And has high structural integrity and low thermal conductivity. In a preferred embodiment, the head-catalytic converter has about 600 cpsi and has a wall thickness of about 6 mils. The head-catalytic converter in this embodiment has a wall flow configuration. In a preferred embodiment, the head-catalytic converter has a substantially pyramidal groove shape with a substantially square opening (or hole). In a preferred embodiment, the catalytic substrate of the head-catalytic converter is made using a comb method. In this embodiment, the head-catalytic converter can catalyze both oxidation and reduction of pollutants, for example, it has a catalyst that can oxidize pollutants and has a catalyst that can reduce pollutants. The head-catalytic converter is used in some embodiments alone or in combination with a pre-catalytic converter. In a preferred embodiment, the head-catalytic converter includes a hybrid mat. The head-catalytic converter can be used for all internal combustion engines. The head-catalytic converter can be used with a fuel addition catalyst.

  One or more head catalytic converters may be used with the same engine. The use of a head catalytic converter in accordance with the present invention also has one or more of the following benefits: reduced weight of the underfloor exhaust system; increased intercooler lifetime due to increased filtration of exhaust particulate matter that the intercooler will pick up Improved; no need for mats; reduced rattling noise in heat shield; reduced muffler size; increased particulate burnout; in one embodiment, even in the event of failure of one head catalytic converter, exhaust gas is in other functions It is effectively processed by a head catalytic converter (eg, the other three in a four cylinder engine). Head catalytic converters are beneficial for boats, ships, motorcycles, small hand held engines, leaf blowers and related engines, and in other applications where non-exposed catalytic converters are preferred.

  In another embodiment, the catalytic converter of the present invention can be placed between the head and the exhaust manifold, as shown in FIG. In this embodiment, the catalytic converter section is placed between the engine head and the exhaust manifold. An advantage over conventional systems is that the converter is very close to the combustion chamber and thus increases efficiency. For example, this embodiment can place them on a Ford 4.6 liter and it will fit all of their engines. This in turn means that it is compatible with Ford Explorer, Mustang, Crown Victoria, Econoline, 150/250/350 pickups, Expedition and Ford all other products that carry engines, such as Lincoln products. It also fits in some embodiments that has been used for many years in various model years using it. One of its 4.6 castings is useful for millions of vehicles in the United States alone. Similarly, it is convenient to include an oxygen sensor.

In another embodiment, the present invention is directed to a post-catalytic converter having a catalytic substrate comprising an nSiRF-C composite and a catalyst. In another embodiment, the catalytic converter of the present invention is a post-catalytic converter. The post-catalytic converter is placed after the mani-catalytic converter. In one embodiment, the post-catalytic converter comprises a catalytic substrate of the present invention, wherein the substrate has a density of about 12 lb / ft ³ , a porosity of about 97%, and a low thermal expansion And has high structural integrity and low thermal conductivity. In a preferred embodiment, the post-catalytic converter has about 600 cpsi and has a wall thickness of about 6 mils. The post-catalytic converter in this embodiment has a wall flow configuration. In a preferred embodiment, the catalyst substrate of the post-catalytic converter is made using a comb method. In a preferred embodiment, the post-catalytic converter has variously shaped, for example, triangular, square and hexagonal slots. Similarly, the slot can vary. In this embodiment, the post-catalytic converter can catalyze both oxidation and reduction of pollutants, for example, it has a catalyst that can oxidize pollutants and has a catalyst that can reduce pollutants. The post-catalytic converter is used in some embodiments alone or in combination with the pre-catalytic converter. In a preferred embodiment, the post-catalytic converter includes a non-intumescent mat. The post-catalytic converter can be used for all internal combustion engines. In another embodiment, a post-catalytic converter can be used with a fuel addition catalyst. In general, the post-catalytic converter of this embodiment is placed near the standard muffler position, but other positions are possible. In an alternative embodiment, the post-catalytic converter is incorporated into the muffler. Such an embodiment can be a) acting as a muffler and replacing the muffler itself, or b) the substrate being placed inside a typical metal muffler assembly, so that it is incorporated into the muffler. Things can be included.

  In another embodiment, the present invention is directed to a diesel oxidation catalyst (DOC), wherein the DOC substrate is a catalyst substrate as described herein. In a preferred embodiment, the substrate of the DOC of the present invention is AEBT or OCBT, preferably AEBT-10, AEBT-12, AEBT-16 or OCBT-10. Embodiments of DOC have a catalyst selected from the group consisting of palladium, platinum, rhodium, mixtures thereof, and derivatives thereof.

  Other suitable embodiments include a catalyzed DPF comprising a catalyst substrate of the invention, preferably a substrate comprising an AETB material, such as AEBT-12, and further comprising a catalyst.

Particle filter (DPF, DPT)
In another embodiment, the present invention is directed to a particle filter comprising the catalyst substrate of the present invention. The particle filter of the present invention can be used in an engine exhaust system in a manner similar to that in which a known catalytic converter is used. Of course, the particle filter of the present invention has advantages over prior art catalytic converters. Because of these advantages, the catalytic converter can be used in a manner where known catalytic converters cannot be used.

  In another embodiment, the present invention is directed to an improved particle filter, the improvement comprising a novel substrate as described herein. Any one of the specific embodiments of the substrate can be used in the improved particle filter.

  In another embodiment, the present invention is an improved particle filter for treating internal combustion engine exhaust comprising a filtration substrate, wherein the improvement extends into the substrate and optionally includes a plurality of grooves through the substrate. Directed to a filter comprising a substrate comprising an nSiRF-C composite. The configuration of the grooves can vary as described above.

  In another embodiment, the present invention is an improved particle filter for treating internal combustion engine exhaust comprising a filtration substrate, wherein the improvement extends from about 100 to about 1,000, preferably extending partially through the substrate. Includes a substrate comprising an nSiRF-C composite having about 600 grooves, wherein the substrate is directed to a filter having a wall flow configuration.

  In another embodiment, the present invention is directed to an improved particle filter for treating internal combustion engine exhaust comprising a substrate and a metal oxide washcoat, wherein the improvement is a filter comprising a substrate comprising AETB.

In another embodiment, the present invention is directed to a diesel particulate filter (DPF) having a filtration substrate comprising an nSiRF-C composite as described above. The filtration substrate is configured to be suitable for use in a DPF. The DPF is partially or wholly placed in the engine head. In one embodiment, the DPF comprises a filtration substrate of the present invention, wherein the substrate has a density of about 12 lb / ft ³ , has a porosity of about 97%, exhibits low thermal expansion, Has high structural integrity and low thermal conductivity. In a preferred embodiment, the mani-catalytic converter has about 600 cpsi and has a wall thickness of about 6 mils. The mani-catalytic converter in this embodiment has a wall flow configuration. In a preferred embodiment, the mani-catalytic converter has a substantially box-shaped (various length through the substrate) groove shape with a substantially square opening (or hole). In a preferred embodiment, the catalyst substrate of the mani-catalytic converter is made using a comb method. Further in this embodiment, the catalyst substrate comprises an alumina washcoat. In this embodiment, the mani-catalytic converter can catalyze both the oxidation and reduction of pollutants, for example, it has a catalyst that can oxidize pollutants and has a catalyst that can reduce pollutants. The cani of the mani-catalytic converter is prepared by swage processing. In a preferred embodiment, the mani-catalytic converter comprises two substrate units. The mani-catalytic converter is used in some embodiments alone or in combination with a pre-catalytic converter. In a preferred embodiment, the mani-catalytic converter includes an expandable mat. The mani-catalytic converter can be used for all internal combustion engines. The mani-catalytic converter can be used with a fuel addition catalyst. Further, the substrate of the mani-catalytic converter can be reinforced. The protective coating can be applied to the inside of the substrate or to its outer surface.

Can-sealed type The catalytic converter of the present invention has a canister. The canister can be prepared according to methods known in the art. Further, the catalytic converter or particle filter canister of the present invention can be manufactured using materials known in the art, such as steel.

  In a preferred embodiment, the catalytic converter of the present invention has an outlet pipe that can be attached to the rear exhaust pipe of a commercial vehicle. Preferably, the catalytic converter is compatible with a rear exhaust pipe having a diameter of about 2 and 1/2 or 3 inches.

  For example, suitable canisters include those made according to any one of the following methods: clamshell, tourniquet, shoebox, stuffing and swaging. The above can sealing method utilizes two different gap control mechanisms: (1) fixed gap and (2) fixed can sealing force. From the viewpoint of the welding process, the method produces a converter having one or more seams. These classifications are illustrated in Table 3 (Rajadurai 1999).

  Sealing the can with a locking force provides more accurate gap density control by eliminating the dimensional tolerance effects of the substrate, can and mat itself. Closing the can to the fixed gap has the advantage of producing a fixed final size converter, which simplifies the converter design, primarily with respect to the welding of the conical portion to the finished can.

  For low aspect ratio circular or elliptical converters, a single seam design is usually preferred, in which case it can provide a uniform gap density distribution. A single seam shell also provides more manufacturing flexibility and does not require expensive tools. Double seam designs are usually required for elliptical converters with high aspect ratios. In this case, the reinforcing rib is embossed by the shell to prevent its deformation and the resulting gap non-uniformity. Double seam shells are manufactured by an embossing process, which requires very expensive tools and must be aligned with a high production volume.

Clamshell In one embodiment, the catalytic converter of the present invention comprises a canister manufactured with clamshell technology. In another embodiment, the particle filter includes a canister made with clamshell technology. In North America, clamshells have traditionally been the most common design for underfloor converters in passenger cars and light trucks. The construction of the clamshell catalytic converter is shown in FIG. The ceramic catalyst substrate (s) is wrapped in a mat and placed on the bottom of the shell. Then another symmetrical part of the shell is constructed on top, compressed together and welded.

  To avoid bypassing the substrate by exhaust gas, tongue and groove designs are used on the mounting mat. The converter also includes an end capping device. The sealing device is used here to protect the mat against gas collisions and corrosion rather than preventing leakage. Most converters that utilize mats do not have end capping devices. Whenever a wire mesh mount is used instead of a mat, a terminal sealing device is required, at least on the entry surface of the substrate.

  Clamshell converters are often equipped with external heat shields. An internal insulation design has also been developed and the inside of the clamshell embossing is lined with an extra layer of insulation.

  Older design catalytic converters included support rings or deep pockets in the clamshell embossing to prevent axial movement of the substrate within the can. Such a strategy is not required for a properly designed converter that utilizes a high holding pressure inflatable mat. There are many automatic converters that do not use the shaft support of the substrate, which still shows impressive durability records. However, shaft support may be required for larger and heavier substrates or if a low holding pressure non-inflatable mat is used. Another consideration is mat corrosion. The converter shell profile or end cone should be designed in a manner that protects the mat from direct impact of hot exhaust gases. Some converter manufacturers impregnate the mat edges, which are exposed to gases and use chemicals to improve their corrosion resistance. The high holding pressure in modern converters also improves the mat resistance to corrosion.

  Dual monolith converters are used in many automotive applications. Two or more monoliths can be used depending on monolith length manufacturing constraints or to merge catalysts with different specifications in one converter. In most dual monolith converters, the substrates are separated by the space held by forming separate pockets during clamshell embossing. In some designs, the space between the substrates is retained by a metal or ceramic ring. A butt monolith position with no space in between is also conceivable. A butt design that provides a lower pressure drop than a spaced design has been used in some commercial converters for gasoline engines (14).

  The converter, shell, and geometry must provide the necessary mat compression. The clamshell profile includes embossed reinforcing ribs to provide the required stiffness and uniform pressure distribution. This is particularly important for flat elliptical catalyst substrates. When designing the ribs, care must be taken that there are no overpressure zones that can cause damage to the substrate or mat. The clamshell method imposes high requirements on monolith dimensional tolerances as well as clamshell embossing. Mat compression during clamshell can sealing proceeds until the half shell is closed, resulting in some gap thickness. The gap thickness is determined by the monolith and shell dimensions. Thus, any variation in monolith size results in variations in mat density and, consequently, can sealing pressure variations that can cause converter durability problems.

  Tourniquet is the most common method that allows direct control of the mounting pressure during the can sealing process. Since tourniquet is not affected by the dimensional differences that can occur between the substrate monoliths, it allows the production of the strongest catalytic converters. Indeed, the tourniquet method is limited to catalyst substrate cross-sections that are circular or nearly circular. Its suitability for elliptical or flat elliptical automatic converters used in the underfloor position is very limited. Tourniquet was once more popular among automakers in Europe, but it has become more common in North America as an automatic converter moved from the underfloor position to the engine close position. Tourniquet is also suitable for large diameter catalytic converters for large diesel engines. A tourniquet catalytic converter is shown in FIG.

  In the tourniquet technique, the substrate is first wrapped in a tong and groove mat. The wrapped monolith is then placed inside a can that is split vertically. The can can be fabricated by rolling a rectangular piece of metal sheet. The rectangular part that comes under the overlap is usually tapered. In some designs, an additional stamping operation forms an overlapping portion of the can into the protruding lip to provide space at the edge of the can below the overlapping portion. Such a design prevents an increase in local pressure that can damage the can seal, especially when the inner edge of the can is cut into a mat or a particularly thin mat is used. The can with the wrapped monolith is then placed in a tourniquet machine that applies control force to the assembly. If the can is still under pressure, it can be tack welded, removed from the machine and seam welded. Push-out testing is sometimes performed as a quality assurance measurement. The axial monolith displacement caused by applying the control force is measured with special test equipment. Finally, the converter header or end cone and the flange and / or mouth are welded to the converter body in a separate operation. By pressing with air while submerged in water, the final assembly can be tested for weld quality.

  The tourniquet machine includes a steel band loop that applies power to the can-sealing parts. One end of the loop is securely attached to the machine, while the other end is pulled by air or hydraulic actuators. In some machines, vibration is applied during can sealing to minimize sealing force and ensure a more even distribution of pressure.

  The actual can sealing force required to reach the target fixed density for a given mat can be determined by a series of tests. Some converters should be sealed using different sealing forces. The can sealing force that produced the desired mat density should be selected. It is important for the tourniquet machine to produce repeated sealing speeds and time patterns due to the reduction in mat pressure. After the target sealing force is achieved, the machine should hold the can in place to allow tack welding rather than a constant force. Applying a constant force to the can when the mat pressure is reduced results in over-compression of the mat.

  The shoebox technique utilizes a split two-part shell similar to the clamshell method. However, the shell is sealed under a clamping force at one edge of the half shell that overlaps the other shell. The shoe box thus provides a strong packaging benefit for tourniquets in connection with its insensitivity to substrate dimensional tolerances.

  Reinforcing ribs can be embossed on the shoebox shell. This technique thus enables can sealing of oblate oval substrates when a tourniquet is inappropriate.

Stuffing In the stuffing technique, the mat-wrapped monolith is pushed into a cylindrical can. The can is usually made from a section of tubing, but it can be rolled and welded with a metal sheet. Non-cylindrical shapes (eg, trapezoidal shapes) are also conceivable. This method is applicable to both small passenger car converters and large converters for large engines. As shown in the figure, the stuffing cone is used to facilitate smooth insertion of the monolith (Non-Patent Document 15). After operation is complete, the end cone is welded to each end of the cylinder to complete the can assembly.

  The packed converter has a similar appearance as the tourniquet assembly, but the actual mechanism of substrate retention is the same as the clamshell design. In particular, the mat fixing pressure is determined by the geometric dimensions of the shell and the monolith. Consequently, high repeatability of the substrate diameter is required when stuffing techniques are used.

  A variation of the stuffing technique (referred to as soft mounting technique) was proposed by Corning (Non-Patent Document 16). The objective was to allow can sealing of ultra-thin wall substrates characterized by low strength with minimal peak mat pressure during stuffing. An important idea is to use a tapered cylindrical tool called an arbor constructed in front of the substrate to capture the peak pressure response of the mat during insertion.

  In the soft mount method, the mat is first inserted into the can where it is held on the flange during the process. The mat backing is then pushed down over the arbor and the substrate (ie, the arbor is configured on the substrate). The arbor is slotted inwardly at the end and easily slides into the can-mat assembly. The arbor compresses the mat against the can in which it moves. As the substrate moves to a position that replaces the arbor in the can, it is not exposed to the instantaneous peak amount required to compress the mat.

Swaging In a swaging converter, the converter shell is normalized to the desired diameter after the mat wrapping substrate is inserted. Swage processing is a newer packaging technique implemented with fully automatic CNC control equipment suitable for mass production for passenger car applications. Swage converters, together with their end cones, can be manufactured from a section of tubing that is obtained in a spinning process on the same manufacturing machine.

  The gap control mechanism can be classified as a constant gap thickness, as it does with stuffing, but the CNC controlled production line can automatically account for the difference in substrate diameter. The swage converter must first be molded to a diameter slightly smaller than the target diameter of the finished product, causing the shell to “spring back” after machining. This is a disadvantage of this method, which can lead to excessive peak pressure and substrate damage during can sealing.

  The catalytic converter header provides a transition between the inlet and outlet tubes and the substrate cross section. Most converter headers are shaped as cones or funnels with axial gas flow. Other designs, such as truncated headers (17) or headers with tangential gas inlets are conceivable, but are not common. The function of the inlet header is to diffuse the inlet flow, ie reduce the gas velocity and increase its static pressure with as little total pressure loss as possible. In fact, the merged header loss can constitute 10% to 50% of the total converter pressure drop, depending on the geometry and flow conditions. These pressure losses can be minimized by designing a converter inlet header that provides a more uniform flow distribution. There is also the concept that a uniform flow distribution in a catalytic converter improves its discharge performance and / or durability. In one embodiment of the invention, the catalytic converter or particle filter has a header with an angle of about 30%.

Mat The catalytic converter or particle filter of the present invention optionally includes a mat. Any of the embodiments listed above or below may include a mat. In some embodiments, the present invention further includes a mat (or mat or batting). For example, the catalytic converter of the present invention, in one embodiment, includes a catalytic substrate, mat and canister as described above. Mats useful for use in the present invention are known in the art.

  The mat in certain embodiments may be selected based on a number of attributes as described herein and known in the art. The catalytic converter canister is preferably designed in such a way as to provide the fixed pressure required for a given catalyst substrate and a given mat. The mat's fixed pressure increases geometrically from its initial bulk density to its final target density during compression. Fixed pressure indicates viscoelastic relaxation, ie the peak initial pressure that occurs during can sealing is significantly reduced for the first few seconds or subsequent minutes due to the reorganization of the mat fibers (Myers 2000). The fixed pressure loss of the expandable mat for relaxation varies by 30-60% of the initial peak fixed pressure.

Due to mat relaxation as well as subsequent pressure loss during use, fixed pressure is not a convenient parameter for specifying the can-sealing process. Instead, a fixed density (often referred to as interstitial bulk density (GBD)) is commonly used for that purpose. Typical mat fixed densities are listed in Table 2 along with their bulk (uncompressed) densities. The exact density for a given application should seek guidance from the mat manufacturer. The exact density for a given application should convey the basis weight and seek guidance from the mat manufacturer. Weight / area is expressed in g / m ² or kg / m ² (these are units of mass rather than weight, and the conventional term “weight / area” is, strictly speaking, “mass / area”. Should be replaced with). Available mats have their weight / area in the range of 1,050 to 6,200 g / m ² and the uncompressed thickness is 1.5 to 10 mm. An inflatable mat of 3,000 to 4,000 g / m ² is typically used for automotive converters. Higher mat weights, such as 6,200 g / m ² (6.2 kg / m ² ), are recommended for more demanding applications or for large converters.

Another important characteristic of catalytic converter fixing mats is their weight / area, sometimes referred to as basis weight. Weight / area is expressed in g / m ² or kg / m ² (these are units of mass rather than weight, and the conventional term “weight / area” is, strictly speaking, “mass / area”. Should be replaced with). Available mats have their weight / area in the range of 1,050 to 6,200 g / m ² and the uncompressed thickness is 1.5 to 10 mm. An inflatable mat of 3,000 to 4,000 g / m ² is typically used for automotive converters. Higher mat weights, such as 6,200 g / m ² (6.2 kg / m ² ), are recommended for more demanding applications or for large converters.

  Packaging mats can be subject to corrosion caused by hot exhaust gas collisions. Resistance to corrosion is an important property of the mat. Resistance to corrosion depends greatly on the pore bulk density (Non-patent Document 18).

  Many other attributes of fixed mats have been identified and / or tested and are available from the mat manufacturer. The list of these attributes includes thermal conductivity, gas sealing attributes, coefficient of friction, and the like.

  During the design of the stationary system, the following considerations are described in certain embodiments.

  Fixed pressure: Assuming that the fixed mat is the only means of connecting the substrate to the shell (ie, the converter does not have an end seal or support ring), due to the radiation pressure combined with the friction of the mat surface, Mechanical linkage is provided. The fixed pressure is the minimum pressure required to hold the substrate in place.

  Peak fixed pressure. As described above, the mat behaves like a viscoelastic solid, producing a high peak fixing pressure during initial compression and then gradually relaxing to reach a residual fixing pressure. For thin wall substrates, the peak pressure can cause damage to the catalyst core during packaging. The transient behavior of the mat must also be taken into account when designing a can sealing method with a constant force, as opposed to a constant gap size like a tourniquet.

  Temperature behavior. For inflatable mats, the mat pressure depends on the temperature reached to activate the vermiculite. An inlet temperature of at least 500 ° C. is required for vermiculite activation; higher inlet temperatures may be required depending on the thermal transition conditions in a particular system. In gasoline applications, the mat is activated on the vehicle during the initial hours of engine operation. Catalytic converter furnace treatment may be required in diesel applications, but in this case the exhaust gas temperature cannot usually reach a sufficient level during vehicle operation. Vermiculite expansion is partially reversible, causing the mat to expand when the temperature increases and contract when the converter is cooled. This property of vermiculite further compensates for the expansion of the converter shell, resulting in a very high fixed pressure at high temperatures. In contrast, non-intumescent mats exhibit a substantially constant fixed pressure throughout the temperature range. The slight decrease in pressure with increasing temperature seen in FIG. 4 can contribute to the gap expansion due to the thermal expansion of the converter shell. At temperatures above 500 ° C., the expandable mat provides a higher holding pressure than the non-expandable mat. However, at temperatures below 500 ° C., the fixing pressure from the expandable mat is actually much lower than that from the non-expandable mat. Non-intumescent mats are therefore a preferred anchoring material in many diesel applications where the converter inlet temperature remains below 500 ° C. An inflatable mat with a low vermiculite content creates a fixed pressure between a conventional inflatable mat and a non-inflatable mat. Hybrid mats exhibit pressure levels similar to non-inflatable mats, but they retain a constant pressure increase at high temperatures, which counteracts gap expansion.

  Gap expansion. When the converter is exposed to high temperatures, the gap thickness increases due to the difference in coefficient of thermal expansion between the substrate and the shell. The thermal expansion of the gap can be a significant source of fixed pressure loss. Gap expansion is particularly important in applications where non-intumescent mats are used because it cannot be compensated by vermiculite expansion. As a design guide, the gap expansion should be kept below 10% (Non-Patent Document 19).

  Gap expansion depends on the following design factors:

  Substrate diameter: Larger substrates produce a higher percentage of gap expansion. Thus, gap expansion can still be a problem in large diesel applications despite the relatively low converter temperature.

  Gap thickness: The thicker the gap, the lower the gap expansion.

  Shell temperature: The higher the temperature, the greater the expansion of the gap.

  Shell material CTE: Steel with higher coefficient of thermal expansion results in higher gap expansion. Thus, the gap expansion is easy to control using ferrite (as opposed to austenite) steel grade.

  Matt aging. Once the converter is operated, the inflatable mat expands resulting in a fixed pressure increase. Many other aging factors, such as the following, are involved in the gradual irreversible loss of fixed pressure: thermal cycling; vibration acceleration and other mechanical factors; mat immersion in water (condensate, vehicle wash); and Organic binder burnout when the mat is first heated.

Advantages and Disadvantages of General Mat Conventional applications utilize expandable and non-expandable fibrous mats for fixing honeycomb substrates in canisters as exemplified in US Pat. According to one conventional system, the fibrous mat can only fix large catalyst members in the canister.

Inflatable mats Inflatable mats were first developed for gasoline converters. By the early 1990s, they became the most common type of ceramic mat used in catalytic converters for all internal combustion engine applications, including diesel. Inflatable mats have the property of partially irreversible expansion once exposed to high temperatures. Thermal expansion curves for mats are available from several manufacturers including 3M and Uniflux. Once expanded, they increase the holding pressure on the substrate, providing a very stable fixation system. Due to their thermal expansion characteristics, inflatable mats can actually increase their fixed pressure at high temperatures to compensate for the fixed pressure loss due to the thermal expansion of the steel housing.

  Intumescent mats are made from alumina-silica ceramic fibers and contain vermiculite that provides their thermal expansion. A typical composition has 30-50% alumina-silica fiber, 40-60% vermiculite, and 4-9% organic binder (typically acrylic latex). After the converter is assembled, the mat must be exposed to a temperature on the order of about 500 ° C. in order to achieve the initial expansion normally achieved in the vehicle during the first hours of engine operation. Organic matte binders that decompose at high temperatures are responsible for the characteristic odor emitted when the mat is first heated.

  The vermiculite component imposes a relatively low maximum operating temperature limit for the expandable mat. The mats dramatically lose their holding pressure at a temperature of about 750 ° C. That temperature is usually defined as the average mat temperature. Thus, the mat can be used at higher exhaust temperatures, but there is a temperature gradient across the mat due to heat loss from the outside of the converter shell. The use of inflatable mats is limited to thermal isothermal applications where heat loss does not occur through the converter wall. Such situations include, for example, a catalyst that is fixed inside the muffler for motorcycle applications.

  A high content of vermiculite constituents is also responsible for the high fixed pressure, especially at higher exhaust temperatures. It has been found that the pressure from the inflatable mat is excessive for the ultra-thin wall substrate, causing potential damage to the part. For these applications, mat manufacturers have introduced low vermiculite inflatable mats (sometimes referred to as “modified” or “second generation” inflatable mats), which provide a lower fixed pressure than previous designs. To do.

Non-intumescent mat The non-intumescent mat does not contain vermiculite. They can therefore provide very high temperature limits of about 1,250 ° C. The main component of the non-intumescent mat is alumina fibers with the addition of an organic binder. In certain embodiments of the invention, the catalytic converter or particle filter includes a substrate as described herein, and the non-intumescent mat can be better with a fibrous material.

  Substrate support relies on built-in compression or fiber “springs”, which provide a constant holding pressure throughout the application temperature range. Since the converter shell expands with temperature, a reduction in effective converter fixing pressure is observed at high temperatures. Therefore, the non-intumescent mat holds the catalyst substrate most stably at a low temperature, contrary to the vermiculite mat. As the temperature increases, the substrate inside the converter is held as the force decreases.

  Non-intumescent mats can be used not only in high temperature applications that cannot withstand high fixed pressures (thin wall substrates), but also in low temperature converters as in the case of diesel engines. Since they do not depend on vermiculite expansion, they do not require furnace treatment in low temperature diesel converters.

Hybrid Mat The improved catalytic converter or particle filter of the present invention can further comprise a hybrid mat. Such mats are known in the art. The hybrid mat, in one embodiment, incorporates a two-layer design: an inflatable mat layer on top of a non-inflatable mat layer. Their attributes and performance are intermediate and have better low temperature fixed pressure than inflatable mats but higher hot pressure than non-inflatable mats. In a preferred embodiment, the improved diesel particulate filter of the present invention includes a hybrid mat for use in both small and large applications.

Wire mesh Knit stainless steel wire mesh can be used in place of the mat to package the ceramic catalyst substrate. Wire mesh is often said to exhibit less favorable pressure characteristics than mats, but is still used in some catalytic converters (traditionally, wire mesh has been used by Ford). In order to prevent the gas from bypassing the base material, the wire mesh always requires a terminal sealing device.

Auxiliary Heat Source As another configuration or exemplary embodiment over that previously disclosed, the filter element may include the addition of a series of electric heating rods that are added to the substrate after the catalyst application. Preferably, the heating element is applied after the catalyst so that the curing process does not harm any electrical contact. In one embodiment, the heating elements or rods are configured about a quarter inch away from each edge or at any desired distance. In some embodiments, wire mesh configurations or other thermal elements described herein that are positioned perpendicular to the gas flow direction and incorporated during the formation of the fiber blank may also be used. The electrical contact can be protected with Nextel fabric or similar material. The heating element is activated before the engine is started as a pre-warmer and continues to operate partially or fully open until the exhaust temperature exceeds the temperature achieved by the auxiliary heating element.

  The use of an auxiliary heat source applied to the filter base can be used to increase the temperature inside the filter base and / or to distribute the additional heat evenly throughout the filter base and make it more efficient. Can be useful. The auxiliary heat source may be composed of a resistive electric heating element. The heating element can have a rod configuration that can be inserted after formation of the filter substrate or during the sol-gel process. The filter substrate has one or more electric heating elements applied, and the heating elements can be heated simultaneously, independently and in a circulated, patterned or random continuous system. . The heating element can be in the form of a wire mesh configuration that can be inserted during or after the filter substrate formation. The filter may use the use of a single wire mesh or multiple wire mesh heating elements, which may be heated simultaneously or independently. Furthermore, the wire mesh heating element can be heated in a circulated, patterned or random continuous system. The heating element may also utilize a rod, spiral or helical configuration that is inserted during or after formation. The filter substrate may incorporate one or more spiral or helical heating elements that can be heated simultaneously or independently, including the use of a circulated, patterned or random continuous system. Finally, the filter substrate can incorporate any combination of the heating elements described above.

  In addition to the resistive electrical heating elements described above, the auxiliary heat source can also use infrared or microwave heating elements. Various heat sources can be supplemented inside the filter base itself, or used to heat the filter base as an external heating element. Furthermore, various heat sources can be applied independently or in combination with any of the other heating elements or heat sources.

  The filter base is placed in a casing that is sufficiently durable to protect the filter base from the normal impacts encountered with vehicle transport. Such casings may include common metal casings such as stainless steel, steel or another alloy. The material can also be a non-metallic, eg ceramic based casing. The filter base can be encapsulated in insulation or padding before being wrapped in the casing. The present invention also includes a heat shield.

  The filter substrate inlet and outlet tubes may be coated with an oxidation catalyst. The catalyst can make the radiation process more quickly resulting in a system that treats the exhaust as a whole in a very short time. The catalyst can be a noble metal catalyst, examples of which include platinum, palladium, or rhodium based, as well as others. The catalyst can be applied directly to the filter substrate surface. Application of the catalyst can be sprayed onto the filter substrate, applied by immersing the filter substrate in a solution, or injected into the filter substrate itself. The use of an oxidation catalyst will promote ignition of particulate matter at low temperatures. Furthermore, the catalyst can also be used as a supplemental heater inside the filter substrate itself.

  The exhaust filter system can be integrated with the engine exhaust path, including integration inside the exhaust manifold of the engine itself. Since the filter base is very resistant to heat and vibration, it can be configured right next to the engine exhaust as it leaves the engine block. The unique ability of the filter base to withstand high heat and increased vibrational stress makes the configuration of the present invention in close proximity to the engine. The close arrangement provides advantages over conventional exhaust filters or catalytic converters that cannot withstand such high heat or vibrational stress.

  Although the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. . Accordingly, the invention is intended to cover modifications and variations of the invention provided that they fall within the scope of the appended claims and their equivalents.

Specific Embodiments of Catalytic Converter The catalytic converter and particle filter of the present invention are further illustrated by the following non-limiting specific embodiments. Many specific embodiments recited herein are intended to illustrate but not necessarily limit the scope of the invention. The catalytic converter of the present invention can be used in any number of engines and vehicles. Thus, in one embodiment, the catalytic converter of the present invention is suitable for use in a vehicle or engine produced by any one of the following companies: Daimler-Chrysler; Chrysler; Dodge; Eagle; Jeep; Plymouth; General Motors; AM General (for example, HUMMER); Bick; Cadillac; Chevrolet; Geo; Mercury; Ace Motor Corp; American MOTORS; Avanti BMW; Daimler-Chrysler; Fiat; Ford; GAZ; General MOTORS; Honda Motor Co., Ltd .; Honda Motor; Car (Toyota); and Volkswagen Group. Others include: Holden; Lightburn; Hartnett; Alpha Sports; Finch; Amuza; Australian Kitcar; FPV; Bavariacars; Birchfield; G-Force; Bomach; Homb; Piper; Daktari; PRB; Daytona; Python; Deuce Customs; RCM; Devax; RMC; DRB; Roaring Forties; Elfin; Robnell; Evans; FN; German; Miesse; Minerva; Nagant; Vivinus; Gurgel; Puma; AE; AC; Allard; Alvis; Ariel; Armstrong Aidle; Ashley; Bond; Bristol; BSA; Caterham; Clan; Daimler; Delow; De Lorian; Elva; FL; Fairthorpe; Ford; Fraser Nash; Gilbern; Ginetta; Hil; J Langer; Lanchester; Land Rover; Lea-Francis; Lister; Locost; Lotus; MR; Marcos; McLaren; MG; Morgan; Morris; Mini; Oreg; Wer; Rolly-Rochdale; Rolls-Royce; Rover; SW; Singer; Standard; Sterling; Sunbeam; Swallow; Talbot; Tornado; Trident; Triumph; Turner; Vland; TVR; ero; Jawa; Laurin &Klement;Praga;Skoda;Tatra;Walter;Kewet;Elcat;Valmet;RaceAbout;Amilcar; Alpine, aka. Bonnet; Bugatti; CD; CG; Citroen; DB; De Dion-Bouton; Delage; Delahaye; Delaunay-Beleville; Sigue; Rheete; Sugit; Talbot; Tracta; Venturi; Voisin; AG; Amphicar; Audi; Auto-Union; BMW; Fendt; Glas; Goggomobil; HP; Heinkel (Heinkel Trojan); Horch; MAN; Magirus; Maybach; Mercedes-Benz; Merku; Messerschmitt; Neoplan; NSU; Opel; Porsche; SW; Smart; Stewer; Twer; T; Hindustan; Mahindra; Maruti; Premier; Reva; San Storm; Sipani; Tata; Abarth; Alfa Romeo; Autobianti; I. Bentati Automobile SpA; De Tomaso; Ita; Lamborghini; Lancia; Maserati; OM; Piaggio; Qvale; Vespa; Zust; Daihatsu Industries (Daihatsu); Honda Motor Co., Ltd. (including Honda); Automobile (Mitsubishi); Mitsuoka Motor (Mitsuboka); Nissan Motor (Datsun) (including Infiniti); Fuji Heavy Industries (Subaru); Suzuki (Toyota) (including Lexus); E Proton; AMI; AMM; Bufori; Inokom; Naza; Perodua; Swedish Assembly; Tan Cong; TD 2000; onkervoort; Spyker; DAF; Pyonghwa; Tokchon; Kewet; Think aka. Pollco; Troll; Syrena; UMM; Aro; Dacia; Marta; Oltcit; Volga; Moskvich; A. M.M. Saab; Scania; Thulin; Tidaholm; Tjorven (sold in the export market as Kalmar); Volvo; and Yugo.

Catalyst or filtration muffler In another embodiment, the present invention is also directed to a catalyst muffler comprising the catalyst substrate or filtration substrate of the present invention. As described herein, the catalyst substrate or filtration substrate is housed together with the muffler in a single canister.

  In one embodiment, the catalyst muffler of the present invention comprises a catalyst muffler of known design in which a prior art catalyst substrate is replaced by the catalyst substrate of the present invention. Suitable known catalyst mufflers include those disclosed in Patent Literature 48, Patent Literature 49, Patent Literature 50, and Patent Literature 51.

Exhaust System In another embodiment, the present invention is directed to an exhaust system comprising the catalyst substrate of the present invention. The exhaust system generally includes a number of components. The exhaust system includes an engine as well as suitable means for directing the exhaust gas in a direction away from the engine.

  The exhaust system includes an internal combustion engine and a conduit for directing exhaust gas in a direction away from the exhaust port of the combustion chamber. Other optional components of the exhaust system include an exhaust manifold, a muffler, and an exhaust pipe.

  In another embodiment, the present invention is directed to an exhaust system comprising the filter substrate of the present invention.

  In another aspect, the present invention is directed to an improved exhaust system that utilizes the catalytic substrate of the present invention. In another aspect, the present invention is directed to an improved exhaust system that utilizes the filter substrate of the present invention.

  The exhaust system of the present invention is suitable for use in any one of the following. 1) Movable on-road engines, equipment and vehicles (automobiles and light trucks; public road motorcycles and street motorcycles; large public road engines such as trucks and buses) 2) Movable off-road engines, equipment and vehicles ( Compression combustion engine (for farm, construction, mining, etc.); Small spark combustion engine (lawn mower, leaf blower, chainsaw, etc.); Large spark combustion engine (forklift, generator, etc.); Marine diesel engine (commercial) Ships, recreational diesel, etc.); marine spark combustion engines (boats, personal sailing vessels, etc.); recreational vehicles (snowmobiles, dirt bikes, all-terrain beagle, etc.); locomotives; , And 3) fixed pollution sources (power plants, refineries, manufacturing plants, etc. Including hundreds of pollution sources). In another embodiment, the present invention is directed to an exhaust system comprising a substrate, catalytic converter, particle filter or catalytic muffler of the present invention.

  Other suitable exhaust systems of the present invention include those used for certain marine applications. The catalyst is typically placed in an exhaust pipe leading from the engine. This exhaust pipe leads to the exit near the stern through the hull of the small ship. This arrangement makes the exhaust pipe susceptible to vibrations, particularly with respect to prior art substrates. Furthermore, in personal ships, the amount of space in which the engine can be configured is limited in order to keep the dimensions of the ship small and lower the center of gravity. In addition, certain prior art substrates, such as cordierite, should not be placed too close to the engine (overheating and melting are possible). A marine exhaust system that includes the catalytic converter or particle filter of the present invention may overcome one or more of these problems. The catalytic converter or particle filter can be configured in the marine exhaust system at the same location where the traditional converter or filter is located, or it can be located elsewhere. For example, in some embodiments, the catalytic converter is smaller than the prior art catalytic converter, but has substantially the same efficiency in removing and / or filtering contaminants (see, for example, US Pat.

  In other embodiments, the exhaust system of the present invention includes one or more additional aftertreatment devices or methods that are used to reduce or limit pollutants emitted from the exhaust system. Suitable devices and methods include CRT, EGR, SCR, ACERT and the like. For example, in one embodiment, the exhaust system includes a catalytic converter of the present invention and a CRT. The exhaust system may further include an SCR system. Further combinations and modifications are contemplated and are understood to be within the scope of the present invention.

In another embodiment, the present invention is directed to an exhaust system comprising _the NO _x adsorbing agent having a catalytic substrate comprising a nSiRF-C composite and a catalyst. The mani-catalytic converter is placed in part or entirely in the engine head. In one embodiment, the mani-catalytic converter comprises a catalytic substrate of the present invention, wherein the substrate has a density of about 12 lb / ft ³ , a porosity of about 97%, and a low thermal expansion And has high structural integrity and low thermal conductivity. In a preferred embodiment, the mani-catalytic converter has about 600 cpsi and has a wall thickness of about 6 mils. The mani-catalytic converter in this embodiment has a wall flow configuration. In a preferred embodiment, the mani-catalytic converter has one groove. In a preferred embodiment, the catalyst substrate groove of the mani-catalytic converter is made using a comb method. Further, in this embodiment, the catalyst substrate includes an optional washcoat. In this embodiment, the mani-catalytic converter can catalyze both the oxidation and reduction of pollutants, for example, it has a catalyst that can oxidize pollutants and has a catalyst that can reduce pollutants. In a preferred embodiment, NO _x combined exhaust system includes an intumescent mats. The mani-catalytic converter can be used in all internal combustion engines. The NO _x combination system is preferably used without a fuel addition catalyst. Generally NO _x combined exhaust system has a substrate to be placed near the muffler, but possible also other locations.

Vehicle In another embodiment, the invention is an improved vehicle, wherein the improvement is directed to a vehicle comprising the catalytic converter or particle filter of the invention. The improved vehicle, in various embodiments, includes any of the specific embodiments of the catalytic converter and particle filter described herein.

  Suitable examples of improved vehicles include vehicles made by one or more of the following: Daimler-Chrysler; Chrysler; Dodge; Eagle; Jeep; Plymouth; General Motors; AM General (eg, HUMMER, etc.); Bilick; Cadillac; Chevrolet; Geo; GMC; Hummer; LaSalle; Oldsmobile; Pontiac; Saturn; Ford; Continental; ; Honda Motor Co., Ltd. (Honda); Mitsubishi car (Mitsubishi); Renault; Peugeut; Toyota (Toyota); Volkswagen Group; and Yugo.

  Residence time or burn-out time is the amount of time that hydrocarbons from the exhaust exhaust stay in the exhaust filter and complete combustion or oxidation. The residence time of the present invention is significantly better than conventional systems. FIG. 19 presents graphs of residence times 1902, 1904, 1906, 1908 required to burn or burn soot at temperatures of 600 Kelvin, 900 Kelvin, 1,000 Kelvin and 1,200 Kelvin, respectively. The more particles have kinetic energy, the more likely the reaction will be successful. As shown in FIG. 19, the residence time 1902 for burning or burning out soot with 0.9 soot mass at 600 degrees Kelvin is much longer than the residence time 1908 at 1200 degrees Kelvin. The longer the residence time, the smaller the acceptable throughput volume, and the greater the risk that more particles will accumulate on the filter and clog the filter pores. Clogging can also be the result of the ceramic material overheating to the melting point, thereby blocking or clogging the pores. Residence time values 1902, 1904, 1906 indicate cordierite samples. Residence times 1902, 1904, 1906 range from about 2 minutes to about 20 minutes to complete the combustion. Residence time 1908 represents one embodiment of the present invention and only takes about 0.75 seconds to complete combustion.

Substrates Substrates 1-7 were prepared as described herein. AETB-12 is available from COI Ceramics Inc. And used as a selected nSiRF-C material having a density of 12 lbs / ft ³ . The substrate / filter was machined from an AETB-12 billet with dimensions of 8x8x4 using the standard carbide drill bit taper machining method described in this patent. The substrate was machined into a cylindrical shape with the following dimensions: radius 2 inches, longitudinal length 1 inch.

  Flow through, wall flow and mixed flow through / wall flow grooves were drilled into the substrate using standard CNC drilling methods described herein and also known in the art. The grooves were drilled using a stainless steel drill bit with a diameter of 0.042 inches at 10,000 RPM. It was observed that during the drilling process, the high heat dissipation and conductivity of the material exposes the drill bit to a high temperature environment that damages the drill bit and eventually melts. Wall thickness was not measured.

  Substrates 1 and 2 had a flow-through configuration. Substrates 3-6 had a wall flow configuration. Substrate 3 had about 25% grooves as flow through and about 75% as wall flow. The substrate 4 had about 50% grooves for flow through and about 50% for wall flow. Substrates 5 and 6 had about 75% grooves as flow through and about 25% as wall flow.

Some of the substrates were coated with an alumina washcoat followed by a 5: 1 Pt: Rh ratio catalyst coating. Specifically, substrates 1, 2 and 7 were not coated with any chemical. Substrates 3, 4, 5 and 6 were applied with a uniform washcoat using standard techniques known in the prior art. The weight of the washcoat applied to each substrate is shown in the column titled “Washcoat Weight”. Following the washcoat, a catalyst mixture containing 5: 1 Pt / Rh was applied to substrates 3, 4, 5 and 6 using standard methods. The mass of the catalyst mixture applied to each substrate / filter is indicated in the column entitled “Mass of catalyst (g / ft ³ )”. A substrate having a washcoat and a noble metal catalyst amount was canned using techniques known in the art.

Preparation of catalyst and filter substrate A substrate / filter was prepared exactly as described in Example 2 unless otherwise stated.

Remarkably different from the substrate / filter in Example 1, the final depth 3/4 inch x 1 inch slag was removed from the CNC, the reverse (mirror image) comb assembly was placed on the CNC punch, The same process as the butt method was used. The end result of this machining method is 600 cpsi, 6 mil wall and 1/2 inch wall flow overlap. As shown in FIG. 28, the dimensions of the substrate / filter in the wall flow configuration are 1 inch diameter by 1 inch thick, and the pattern inside the slug is 0.8 inch by 0.8 inch (square inch). Met. Using this substrate, an early stage Delta P test was successfully performed to observe the pressure drop observed in the N ₂ gas flow due to flow blockage caused by the wall flow configuration. FIG. 29 shows the pressure drop measured in the reactor-tube flow measurement system as a function of gas flow for temperatures of 27 ° C., 29 ° C. and 400 ° C. FIG. 30 shows the pressure drop measured in the same reactor as a function of temperature at a constant flow rate of 125 SLPM. These initial results are positive, indicating that the nSiRF-C substrate / filter does not produce high back pressure in the wall flow configuration.

Catalyst and Filtration Substrate Preparation A substrate / filter was prepared exactly as described in Example 12 unless otherwise noted.

Using AETB-11, AETB-12 and AETB-16 billets (purchased from COI Ceramics Inc.) significantly different from the substrate in Example 1 and having densities of 11, 12, and 16 lbs / ft ³ respectively Different substrates were produced.

  For substrates / filters made from AETB-11 with a final depth of 3/4 inch x 1 inch slag, the comb assembly is removed from the CNC and the reverse (mirror image) comb assembly is placed on the CNC punch to pierce the hole The same process as the law was used. The end result of this machining method is 600 cpsi, 6 mil wall and 1/2 inch wall flow overlap. For substrates / filters made from AETB-12 and AETB-16 with a final depth of 7/8 inch x 1 inch slag, the comb assembly is removed from the CNC and the reverse (mirror image) comb assembly is placed on the CNC punch, The same process as the piercing method of drilling was used. The end result of this machining method is 600 cpsi, 6 mil wall and 3/4 inch wall flow overlap.

  All substrate / filter dimensions tested at this stage were 1 inch diameter by 1 inch thick. The substrate was exposed to another early stage Delta P test to observe the pressure drop observed for substrate material density and wall flow configuration as a function of time per hour as a function of space. This particular test was performed at a temperature of 932 ° F. The test results are summarized in FIG. In addition to the data observed for our AETB-11, AETB-12 and AETB-16 substrate filters, their 400 / 6.6 flow-through cordierite substrate / filter and 200 / reported by Corning The results for 12 cordierite DPT (wall flow configuration) are also shown. Corning data was obtained from Corning Technical Reports. While Corning DPT in the wall flow configuration produces excessive back pressure compared to cordierite flow-through filters, our nSiRF-C filters are equivalent to cordierite flow-through substrates even when they are used in wall flow configurations Our results show that this creates a back pressure of. As observed in FIG. 31, the use of wall flow DPT made from nSiRF-C material as invented in this patent provides a good alternative because back pressure was a major problem in wall flow DPT. , Is estimated. Furthermore, the comparison of back pressure observed with the AETB-11 substrate / filter vs. AETB-12 and AETB-16 substrate / filter, it is speculated that an increase in “overlapping” groove length results in better back pressure performance. It was also observed.

  FIG. 32 is the same test performed at an operating temperature of 1,100 ° F., and the trend in results is almost the same.

Preparation of catalyst and filter substrate A substrate / filter was prepared exactly as described in Example 2 unless otherwise stated.

AETB-12 was purchased from COI Ceramics Inc. and used as a selected nSiRF-C material having a density of 12 lbs / ft ³ . Laser-based groove drilling techniques were tested and holes were made at 3,000 cpsi and 30,000 cpsi. The holes were drilled using a DPSS laser system as described herein and as described elsewhere in the related prior art. The holes made using a pulsed high energy laser system were square in shape and showed a high front surface area due to the specific configuration. The presence of a high front surface area (caused by large values for groove wall thickness) was evident in the Delta P test performed using the same test flow reactor described in Example 3. It was observed that for early stage prototypes successfully created using laser-based drilling techniques, the delta back pressure should result in a water value of less than 10 inches. Further modifications can be made to reduce (or increase) cell density and change wall thickness, as dictated by application needs.

FIG. 33 shows the change in pressure as a function of N ₂ gas flow for an AETB-12 substrate / filter having a cell density of 30,000 cpsi at 27 ° C. and 400 ° C. FIG. 34 shows the change in pressure as a function of operating temperature for various N ₂ gas flow rates for AETB-12 substrates / filters with a cell density of 30,000 cpsi.

FIG. 35 shows the change in pressure as a function of N ₂ gas flow for an AETB-12 substrate / filter having a cell density of 30,000 cpsi at 29 ° C. and 400 ° C.

A diesel particulate filter AETB formulation is used to make a substrate and formed into billets having dimensions of about 13 inches x about 13 inches x about 5 inches with a density of about 8 pounds / cubic foot. A 5 inch tall cylindrical slug (6 inches in diameter) is cut from the billet using a saw with a diamond at the tip. This substrate is further machined to accurate tolerances (within 0.001 inches) on a rotating lathe.

  Next, a plurality of grooves are formed in the substrate to form a substrate containing 600 / cubic inch grooves and having a wall flow configuration. Grooves are formed using the composite drilling and combing techniques described herein. The grooves are square with dimensions of about 6 mils × 6 mils. Adjacent walls of adjacent grooves are substantially parallel to each other. The grooves do not extend through the entire length of the substrate and are approximately 4.9 inches long.

Measurement of Total Surface Area The first and second cordierite samples have a total surface area of 33.2 and 46.97 square inches / cubic inch, respectively. Thus, within 1 cubic inch of the first cordierite sample, there is a 33.20 square inch surface for placing a precious metal load. One sample of the substrate of the present invention has a total surface area of 83.58 square inches / cubic inch.

The total wall volume for the first and second cordierite samples is both 0.311 in ³ / in ³ (cubic inch / cubic inch). The total wall volume of the substrate of the present invention is 0.272 cubic inches / cubic inch. This value is lower than the first and second cordierite samples, but the present invention has a much higher porosity and permeability, making the smaller total wall volume more efficient.

Activity test The activity test measures the amount of contaminants entering and exiting the filter. In one activity test, a sample filter is placed in the reactor and a gas of known flow rate and temperature is pumped through the material. The activity test then measures the amount of contaminant that exits the filter. Referring to FIG. 24, an activity test of an exemplary substrate 2410 and cordierite sample 2420 of the present invention is shown. The test measured the activity of toluene at a concentration of 500 ppm and a space velocity of 40,000 / hour. The cell density of the two samples was both 400 cpsi.

  The test illustrates that the substrate 2410 of the present invention has a faster ignition time (at a significantly lower temperature) than the cordierite sample 2420. The substrate 2410 achieved 85% failure at a temperature of about 335 ° F. in about 3-4 seconds. Cordierite 2420 achieved 85% failure at about 380 ° F. Substrate 2410 achieved 90% failure at about 360 ° F. in about 4-5 seconds. Cordierite 2420 achieved 90% failure at about 450 ° F. in about 8 seconds. Substrate 2410 achieved nearly 100% failure at about 425 ° F. in about 5 seconds. Cordierite 2420 is expected to achieve nearly 100% failure at about 800 ° F. in about 28 seconds.

The Permeability of the Catalyst Substrate The permeability of the exemplary embodiment of Example 2 of the present invention is about 1,093 cd (centipalcy). Other test values exceeded the maximum number measured by the test facility. In comparison with conventional systems, the cordierite sample has a permeability of about 268 cd.

Example 2 Catalytic Converter Test Similar to the activity test, EPA is known as the Federal Test Procedure (“FTP”) 75 which actually secures the filter in the rear exhaust of the car and drives the car under certain conditions. Take advantage of the test. EPA uses this test for vehicle emissions certification. The FTP 75 tests the state of the vehicle in three stages. The first stage includes crank and non-idling hold and operation for 505 seconds. This stage operates at ambient temperature, but the engine and emission control system does not perform at an optimal level until the middle of the move (ie, the catalyst is cold and the “ignition” required to efficiently control the exhaust from the engine. "The temperature has not been reached), reflecting the condition experienced at the beginning of the move. The second phase includes 864 seconds of operation with no idling, pause, and 5 seconds of temporary sampling. This stage reflects the state of the engine when the vehicle is in continuous operation running long enough for all systems to achieve a stable operating temperature. The vehicle then has an immersion time of 540 seconds to 660 seconds. This immersion time reflects the condition of the engine that was stopped and not cooled to ambient conditions. The third stage is crank and non-idling hold and operation for 505 seconds. Under these circumstances, the engine and catalyst are warmed and not at peak operating efficiency at start-up, but still have sufficiently improved emissions performance compared to the cold start mode.

Thermal Testing of Catalyst Substrate The thermal conductivity of an exemplary embodiment of the present invention is about 0.0604 W / m-K (thickness (meter) and wattage of energy per Kelvin change). For comparison, cordierite samples are about 1.3-1.8 W / m-K. These results show that if 1,000 watts of thermal energy is lost from a given volume of cordierite material, only 33 watts are lost from the same volume of material from the present invention. Therefore, the material of the present invention has a thermal conductivity 30 times greater than cordierite.

  The specific heat of an exemplary embodiment of the present invention is about 640 J / kg-K (joules / kilogram-kelvin). The cordierite sample is about 750 J / kg-K. Even though cordierite has a higher specific heat, the cordierite filter has a larger mass to heat. The result is that more thermal energy is needed to achieve operating temperatures that make cordierite less efficient.

  Many service temperature limits are the maximum temperatures at which a material can be used many times without any decomposition. The higher the temperature at which the substrate can continue to operate without microfracture or fracture, the lower the chance of breaking or splitting over time. This therefore means that the substrate has greater durability over a wide temperature range. High temperature limits are preferred.

  Many service temperature limits of exemplary embodiments of the present invention are 2,980 ° C. The cordierite sample is at about 1400 ° C. Thus, the material of the present invention can withstand more than twice the temperature of cordierite before breaking. This allows the material to function in a wider range of exhaust environments.

  The coefficient of thermal expansion is the ratio of increase over the original length, area or volume of the body length (linear coefficient), area (square) or volume for a given temperature rise (usually zero to 1 ° C.) It is. These three factors are in a ratio of approximately 1: 2: 3. If not specifically expressed, cubic coefficients are usually intended. The fewer substrates that expand when heated, the less chance of leakage, breakage, or damage to the filter assembly. A lower thermal expansion is preferred to ensure that the substrate retains its dimensions even when heated or cooled.

The coefficient of thermal expansion for an exemplary embodiment of the present invention is about 2.65 × 10 ⁻⁶ W / m-K (watts / meter Kelvin). Samples of cordierite is about ^{2.5 × 10 -6 W / m-} K~3.0 × 10 -6 W / m-K. The thermal expansion of the material of the present invention is less than 10 times that of cordierite.

  The coefficient of thermal expansion of the substrate is preferably comparable to that of the washcoat in one embodiment. If the coefficients of thermal expansion are not similar, the washcoat breaks, delaminates, becomes “flakes”, or begins to flake off the substrate and blows away precious metal or fills the pore space. This ultimately results in increased back pressure, overheating and system failure.

Structural integrity The tensile modulus of AETB-12 is about 2.21 MPa (megapascal pressure, which is equal to about 100,000 times one atmospheric pressure). The cordierite sample is about 25.0 MPa. Cordierite is about 10 times stronger, but the material of the present invention can withstand 200,000 atmospheric pressure prior to rupture. This value is sufficient for the uses described herein.

Acoustic testing Acoustic attenuation can be defined as thickness reduction, thinning, grinding; density reduction; force or strength reduction; or weakening. In one embodiment of the present invention, acoustic attenuation is the ability of the substrate to attenuate or extinguish acoustic energy in the engine exhaust. The substrate of the present invention can replace or supplement an engine's muffler assembly as disclosed herein, thus reducing exhaust noise and exhaust system costs. Higher sound attenuation is preferred.

  Currently, there are no official laboratory tests that can be applied to the present invention in any configuration. The American Society for Testing and Materials (“ASTM”) official test applies to large spaces such as soundproof rooms, but not to one material. However, a simple test using a volume meter has revealed that when the substrate of the present invention is present in an exhaust system, the noise from the automobile is at least 25 decibels, which is lower than that of a conventional silencing vehicle. For reference, 110 dB is a level that causes permanent damage to the human ear, and 60 dB is the amount of noise in a luxury car that is idling with the window closed.

Comparison with prior art substrates A sample of the appropriate nSiRF-C (AETB-12) was compared to cordierite and SiC to determine a number of attributes.

  In one embodiment, the substrate of the present invention is 6 mil walls and has 600 cpsi. The cell density of the sample substrate of the present invention is compared with two samples of cordierite. For comparison, the first and second cordierite samples are 100 cpsi at 17 mil wall thickness and 200 cpsi at 12 mil wall thickness, respectively. For comparison, the substrate of the present invention, in this embodiment, is 600 cpsi and has 6 mil walls.

  In this exemplary embodiment, the substrate is perforated with a groove diameter of 0.04 inches at 0.06 inch intervals across the filter. These grooves are smaller than conventional cordierite grooves. As a result, a much larger and increased surface area is produced compared to cordierite without taking into account the surface area present in the large pore space of the substrate material. The groove is preferably a “blind” groove. Rather than flowing through and out of the groove without reaction with the catalyst, the exhaust exhaust is swept through the groove wall.

  Grooves are drilled using a computer controlled CNC drill to maintain uniformity. The drilling process is performed under a constant water shower to prevent the floating of dust that is an OSHA hazardous material and can adhere to and destroy the drill's bearings.

  After the perforated substrate is oven dried to drive out or burn off any water or other liquid that may remain in the pore space, any catalyst is applied. The baking time is not adjustable and water evaporation can be determined by simply metering the substrate. The baking time mainly accelerates the dehydration process. After heating the filter element several times at different intervals, the weight decreases uniformly and the substrate is easy to apply any catalyst or coating.

Glossary The term “substrate” as used herein refers to a solid surface on which contaminants can be converted to non-contaminant. Substrate is understood to include filter elements, catalyst substrates or filtration substrates.

  The term “high grade refractory fiber” as used herein refers to.

  The term “sintered” as used herein refers to a material that has been heated without melting.

  The term “nonwoven” as used herein means that there is no interlacing or interwoven pattern of fibers.

  The term “billette” as used herein refers to an unshaped or non-machined block of substrate material.

  The term “green billet” as used herein refers to an uncured billet.

  The term “front surface” as used herein refers to the surface through which fluid enters the substrate. In some embodiments, the groove has an opening in the front surface and the groove is perpendicular to the front surface.

  The term “back surface” as used herein refers to the surface from which fluid exits the substrate. In some embodiments, the groove has an opening in the back surface and the groove is perpendicular to the back surface.

  The term “mil” as used herein refers to a unit of measurement and is equal to one thousandth of an inch.

  The term “ignition temperature” as used herein refers to the temperature at which the conversion of the reaction in the catalytic converter is 50%. That is, the ignition temperature is the temperature at which 50% of one or more pollutants or total pollutants are converted to non-pollutants.

  The term “burn out” as used herein refers to the process of burning particulate matter and other materials filtered by a substrate. For example, burnout can occur in a diesel particulate filter (DPF).

  The term “groove” as used herein refers to a three-dimensional opening in a substrate that extends through at least a portion of the substrate and has a well-defined shape and length.

  The term “grooves per square inch” as used herein refers to the number of grooves present in a square inch of a substrate cross-section. The term cells per square inch is a synonym.

  The term “groove shape” as used herein refers to the three-dimensional shape of the groove.

  The term “PM” as used herein refers to particulate matter. General measurements of PM include PM-10 and PM-2.5.

  The term “total surface area”, as used herein, is the total surface area and represents the total surface area that a precious metal can be impregnated in 1 cubic inch.

The term “2-way catalytic converter” as used herein refers to a catalytic converter that only oxidizes CO ₂ and H ₂ O to HC and CO in the gas phase contamination.

The term “3-way catalytic converter” as used herein refers to a catalytic converter that oxidizes CO and HC to CO ₂ and H ₂ O and also reduces NO _x to N ₂ .

  The term “4-way catalytic converter” as used herein performs oxidation and reduction as described above for 3-way catalytic converters and also traps particles and burns them out (regeneration). Refers to a catalytic converter (which can occur in an active or passive manner).

  The term “suitable for use” as used herein refers to meeting the requirements of certain regulatory guidelines.

  The term “thermal conductivity” as used herein refers to a given material per unit time when its opposite surface is subjected to a unit temperature gradient (eg, a temperature difference of 1 degree across a unit thickness). Refers to the amount of heat that passes through the unit area of the plate.

  The term “mat” as used herein generally refers to any material used to provide thermal insulation and / or protection to a substrate. The mat is sometimes called stuffing.

  The term “boron binder” as used herein refers to an agent that is present in the nSiRF-C after the sintering process and is derived from the boron binding agent.

  The term “sticking” as used herein refers to whether a groove is formed in a substrate by causing the substrate material to repeatedly move the pointed tip in and out until a groove of the desired length is obtained. Or refers to the process of reshaping.

  Having described the invention in detail, the same can be done within a broad and equivalent range of conditions, formulations, and other parameters without affecting the scope of the invention or any embodiment thereof. Would be understood by those skilled in the art. All patents and publications cited herein are hereby incorporated by reference in their entirety.

1 is a cross-sectional view of a conventional cordierite substrate incorporating a honeycomb structure. The honeycomb structure 302 is formed in the cordierite filter element 300. The honeycomb structure 302 is formed using an extrusion process, in which case a long groove (or tube) with a major axis parallel to the extrusion action is created. The openings in these grooves face the incoming exhaust air flow. As the exhaust enters the groove, the particles will deposit along the internal partition of the tube. A micrograph is shown. A micrograph is shown. In FIG. 2b, sphere 210 represents PM-10 size particles and sphere 225 represents PM-2.5 size particles. FIG. 2 is a photomicrograph of cordierite 205 with a sphere 210 representing PM10 particles, with a second sphere 225 representing PM2.5 particles. 1 is a longitudinal cross-sectional view of a typical catalytic converter schematic. The catalytic converter 400 includes a reduction catalyst 402 and an oxidation catalyst 404. As exhaust stream 406 enters catalytic converter 400, it is filtered and exposed to reduction catalyst 102 and then to oxidation catalyst 404. The exhaust stream 406 is then treated by an oxidation catalyst 404, which further burns non-burning hydrocarbons and carbon monoxide. The schematic diagram of a catalytic converter is shown. FIG. 4 is a cross-sectional view of a schematic diagram of three substrates having three different front surface shapes. It is a schematic diagram of an example of the flow through structure of a catalyst base material or a filtration base material. The base material has a plurality of grooves 610 formed by the groove walls 620. The fluid stream 630 enters the front surface x, moves through the groove 610, and exits the rear surface. It is a schematic diagram of an example of the wall through structure of a catalyst base material or a filtration base material. The wall flow pattern is composed of the same base material 720 and grooves 710, provided that the grooves 710 are not completely connected to the other side. Instead, the groove 710 is formed as a blind hole, leaving a non-perforated portion 740 of the substrate 720 at the end of the groove 710. The fluid stream 730 then passes through the groove wall 720 and then exits the back surface of the substrate. One particular advantage of the present invention is that the fluid flow 730 in the wall flow pattern has substantially the same characteristics as the flow through pattern. It is a schematic diagram of an example of the wall through structure of a catalyst base material or a filtration base material. In this case, the fluid stream 830 enters the front surface of the substrate. Some fluid exits the back surface of the substrate by flowing through the non-perforated portion 845. FIG. 5 is an end view of an embodiment of a substrate 900 using wall flow grooves. The alternating grooves have non-perforated portions 920 at the entrance or exit. The perforated grooves 910 alternate with the non-perforated portions 920 of the grooves perforated from the opposite side. As a result, the substrate appears to have a “grid” pattern of grooves. A comparison of front surface areas 1020, 1021, 1022, 1023 is shown, and cell numbers 1010, 1011, 1012, 1012 are shown. In the comparison of FIGS. 10a and 10c, each embodiment has the same cell density, i.e. the number of grooves or cells. However, FIG. 10c has a very large front surface area. Ideally, the front surface area is minimized so that structural integrity still remains. With respect to FIGS. 10a-10d, the embodiment of FIG. 10b has a preferred structure; the cell density is maximized and the front surface area is minimized. A comparison of front surface areas 1020, 1021, 1022, 1023 is shown, and cell numbers 1010, 1011, 1012, 1012 are shown. Ideally, the front surface area is minimized so that structural integrity still remains. Similar comparisons can be made between the embodiments of FIGS. 10b and 10d. With respect to FIGS. 10a-10d, the embodiment of FIG. 10b has a preferred structure; the cell density is maximized and the front surface area is minimized. A comparison of front surface areas 1020, 1021, 1022, 1023 is shown, and cell numbers 1010, 1011, 1012, 1012 are shown. In the comparison of FIGS. 10a and 10c, each embodiment has the same cell density, i.e. the number of grooves or cells. However, FIG. 10c has a very large front surface area. Ideally, the front surface area is minimized so that structural integrity still remains. With respect to FIGS. 10a-10d, the embodiment of FIG. 10b has a preferred structure; the cell density is maximized and the front surface area is minimized. A comparison of front surface areas 1020, 1021, 1022, 1023 is shown, and cell numbers 1010, 1011, 1012, 1012 are shown. Ideally, the front surface area is minimized so that structural integrity still remains. Similar comparisons can be made between the embodiments of FIGS. 10b and 10d. With respect to FIGS. 10a-10d, the embodiment of FIG. 10b has a preferred structure; the cell density is maximized and the front surface area is minimized. Fig. 4 shows an embodiment of a square groove for dimensioning. In this embodiment, the ratio of cell void 1110 to cell wall 1120 is 31.83: 1.5 or about 20: 1. 12 illustrates one embodiment of a substrate 1210 having an exemplary cell void to cell wall ratio shown for sizing. The substrate 1210 includes four squares 1220, 1221, 1222, 1223 that are 4 square inches long and 1 and 1/8 inch wide by 1 and 1/8 inch. Each of the four squares 1220, 1221, 1222, 1223 is perforated to have a cell density of 900 for a total substrate cell density of 3,600. The wall thickness between the cells is 1.5 mil. The spacing between each of the squares 1220, 1221, 1222, 1223 on the substrate 1210 is 7/8 inch, and each of the squares 1220, 1221, 1222, 1223 is about 7/16 inch from the nearest edge of the substrate 1210. It is. Fig. 4 shows some embodiments of a groove structure. FIG. 13 a shows a hexagonal groove 1310. All of these embodiments can implement the present invention because the walls 1315 of the grooves 1310 are substantially parallel to each other. Fig. 4 shows some embodiments of a groove structure. FIG. 13 b shows a triangular groove 1320. All of these embodiments can implement the present invention because the walls 1325 of the grooves 1320 are substantially parallel to each other. Fig. 4 shows some embodiments of a groove structure. FIG. 13 c shows a square groove 1330. All of these embodiments can implement the present invention because the walls 1335 of the grooves 1320 are substantially parallel to each other. 1 illustrates one embodiment of the present invention. The micrograph shows rectangular grooves 1410, 1411, 1412, 1413 of substantially similar dimensions in the substrates 1415, 1416, 1417, 1418. Figures 14c and 14d illustrate fibers 1420, 1421 present in the material. These fibers are porous, which is superior to the platelet-shaped cordierite in conventional systems. 1 illustrates one embodiment of the present invention. The micrograph shows rectangular grooves 1410, 1411, 1412, 1413 of substantially similar dimensions in the substrates 1415, 1416, 1417, 1418. 1 illustrates one embodiment of the present invention. The micrograph shows rectangular grooves 1410, 1411, 1412, 1413 of substantially similar dimensions in the substrates 1415, 1416, 1417, 1418. FIG. 14c illustrates fibers 1420 present in the material. These fibers are porous, which is superior to the platelet-shaped cordierite in conventional systems. 1 illustrates one embodiment of the present invention. The micrograph shows rectangular grooves 1410, 1411, 1412, 1413 of substantially similar dimensions in the substrates 1415, 1416, 1417, 1418. FIG. 14d illustrates the fibers 1421 present in the material. These fibers are porous, which is superior to the platelet-shaped cordierite in conventional systems. 2 is a two-dimensional view of a comb 1500 that can be used in a combined method of preparing the catalyst substrate or filtration substrate of the present invention. FIG. 9 shows various views of a comb 1600 (or portion thereof) that may be used with certain embodiments of the invention. FIG. 16 also presents exemplary physical dimensions (in inches) of the comb 1600. It is a schematic diagram of the surface area expansion which can be formed in the filter element of embodiment of this invention, and an inflow port and an outflow port. FIG. 17 provides a fluid flow 1704 that enters the groove opening 1702 on the front surface. The fluid exits from the right hand side of the back surface of the 1704 substrate. The substrate shown in FIG. 17 illustrates a substrate having a wall flow configuration, where the grooves gradually reduce in size as the grooves extend from the groove openings through the substrate to the groove ends. It is a longitudinal direction figure (photograph) of one base material embodiment of this invention. A filter substrate 1800 of the present invention is shown. The substrate 1800 has a hard coating 1804 on the outer wall 1802. For the sample shown in FIG. 18, the hard coating consists of finely ground cordierite and inorganic fibers. The powder was also applied on the filter base 1800 and cured as described herein. The hard coating protects and insulates the filter foundation without changing dimensions. Fig. 6 is a graph showing the residence time required to bake particulate matter at various temperatures. This graph presents the residence time required to burn or bake particulate matter (smoke mass) at various temperatures. As shown, the residence time required to burn or bake the soot mass with an initial 0.9 soot mass at 600 Kelvin is much longer than the residence time at 1200 Kelvin. An exhaust substrate system 2000 including a substrate 2002 combined with a wire mesh heating element 2004 is presented. The substrate 2002 and the wire mesh heating element 2004 are inserted into the exhaust casing 2006 at an angle with respect to the exhaust flow. Since the wire mesh heating element 2004 is configured behind and below the substrate 2002 as a result of this angle, the substrate 2002 can be heated more efficiently and the known principle of increasing heat can be uniformly utilized. As described above, more uniform and efficient heating causes the substrate 2002 to more completely burn or ignite the particles, resulting in cleaner exhaust. FIG. 10 is a front view of filter element 2102 and wire mesh heating element 2104 described and discussed in connection with FIG. As can be seen, the filter element 2102 and the wire mesh heating element 2104 are shaped oval to fit within the casing at an angle. The casing shape, filter element 2102 shape, heating element 2104 type, and angle can all be modified to meet the requirements and limitations of the intended exhaust system application. It is the microscope picture of the base material of this invention, especially AETB. It is the microscope picture of the base material of this invention, especially AETB. Fiber 2205 can be observed. The sphere 2210 illustrates PM-10 size particles, and the sphere 2225 illustrates PM-2.5 size particles. FIG. 7 is a graph showing pressure drop (ΔP) as a function of gas space velocity per hour (hr ⁻¹ ) for seven test materials: Corning 200/12 DPT 932F (2340) AETB-11: 600 cpsi, wall Thickness 0.1524 mm (6 mil) and 176.22 kg / m ³ (11 lb / ft ³ ); 1100 F (2310) AETB-11; 600 cpsi, wall thickness 0.1524 mm (6 mil) and 176.22 kg / m ³ (11 lb / ft ³ ); 932 F (2320) AETB-11: 600 cpsi, wall thickness 0.1524 mm (6 mil) and 176.22 kg / m ³ (11 lb / ft ³ ), 662 F (2330); 1100 F (2350) ) Cordierite; 932F (2360) cordierite; and And cordierite of 662F (2370). It is a graph which shows% destruction versus temperature. The substrate 2410 of the present invention exhibits a material breakdown at a lower temperature that is greater than the cordierite substrate 2420 percentage. 1 is a cross-sectional view of one embodiment of an improved catalytic converter of the present invention. In this embodiment, the catalytic converter includes a heat and fire resistant casing 2502. The casing 2502 has a suction port 2504 and an exhaust port 2506. The improved substrate 2510 has one or more zones 2512, 2514. The modified substrate 2510 is encased or surrounded in one or more layers of mat / insulation 2515. A mat layer 2515 can be applied to the filter foundation 2510 to shield the foundation 2510 from environmental vibration shocks of engines and automobiles and to insulate the external environment from the internal thermal temperature of the filter foundation 2510. 2 is a schematic diagram of a catalytic converter or particle filter 2600 having four substrates 2601a, 2601b, 2601c, and 2601d aligned in parallel. FIG. The filter or converter has a front opening 2604 and a rear outlet 2605. a shows a catalytic converter or particle filter 2700 having a stacked membrane-constituting substrate 2710. Inlet 2720 and outlet 2730 are made at different heights. b shows a catalytic converter or particle filter 2700 having a stacked membrane configuration 2710. Inlet 2720 and outlet 2730 are made at different heights. Figures 27b and 27c show an alternative embodiment. c shows a catalytic converter or particle filter 2700 having a stacked membrane configuration 2710. Inlet 2720 and outlet 2730 are made at different heights. Figures 27b and 27c show an alternative embodiment.

Claims (47)

  Non-woven sintered refractory fibrous ceramic composite material and catalyst substrate or filtration substrate comprising a catalyst, optionally further comprising a washcoat and further comprising a plurality of grooves .   The catalyst substrate of claim 1, wherein the composite material comprises alumina-boria-silica fibers.   The catalyst substrate of claim 1, wherein the composite material comprises alumina-zirconia fibers.   The catalyst substrate of claim 1, wherein the composite material comprises alumina-boria-silica fibers and alumina fibers.   The catalyst substrate according to claim 1, wherein the composite material includes alumina oxide fibers.   The catalyst substrate according to claim 1, wherein the composite material includes oxidized silica fiber.   The catalyst base according to claim 1, wherein the composite material includes alumina boria silica fiber, silica fiber, and alumina fiber.   The catalyst substrate of claim 1, wherein the composite material comprises about 50 to about 90% silica, about 5 to about 50% alumina, and about 10 to about 25% aluminoborosilicate.   The catalyst substrate of claim 1, wherein the composite material is an alumina reinforced thermal insulation (AETB) composite material.   The catalyst substrate of claim 9, wherein the AETB is selected from the group consisting of AETB-8, AETB-12 and AETB-14 and AETB-16.   The catalyst substrate of claim 1, wherein the composite material comprises an orbital ceramic thermal insulation (OCTB) composite material.   The catalyst substrate according to any one of claims 1 to 11, wherein the composite material comprises a boron binder.   The catalyst base according to any one of claims 1 to 12, wherein the catalyst comprises a metal catalyst.   The catalyst substrate according to any one of claims 1 to 13, wherein the catalyst is selected from the group consisting of palladium, platinum, rhodium, mixtures thereof and derivatives thereof. Additionally present in an amount of said catalyst is about 0.035～ about 1.77 kg / ^{m 3} (about 1 to about 50g / ft ^3), the catalyst substrate according to any one of claims 1 to 14.   The catalyst base according to any one of claims 1 to 15, wherein the washcoat contains alumina oxide.   The catalyst substrate according to any one of claims 1 to 16, comprising a plurality of grooves extending along the longitudinal direction in the substrate and including a wall flow configuration, a flow-through configuration, or a combination thereof. 0.45 cm ² having a (1 square inch) from about 100 to about 100,000 groove per the catalyst substrate according to any one of claims 1 to 17. 0.45 cm ² (1 square inch) with about 600 grooves per catalyst substrate according to any one of claims 1 to 18.   20. The catalyst substrate according to any one of claims 1 to 19, wherein the groove is square, triangular, hexagonal and further has a substantially rectangular, trapezoidal or triangular longitudinal cross-sectional shape. Has a front surface area of about 6.45 cm ² to about 323 cm ² (about 1 in2 to about 50 in2), the catalyst substrate according to any one of claims 1 to 20.   The catalyst substrate according to any one of claims 1 to 21, suitable for use in a commercial catalytic converter or a diesel oxidation catalyst (DOC).   The catalyst substrate according to any one of claims 1 to 21, suitable for use with a stationary engine.   The catalyst substrate according to any one of claims 1 to 21, suitable for use in a main catalytic converter, a mani-catalytic converter (mani-cat) or a pre-catalytic converter. About 0.37～ having a density of about 1.00 kg / ^{m 3} (about 6 to about 16lb / ft ^3), the catalyst substrate according to any one of claims 1 to 21.   26. The catalyst substrate according to any one of claims 1 to 25, having an emissivity of about 0.8 to about 0.95.   27. The catalyst substrate according to any one of claims 1 to 26, having a porosity of about 90% to about 99%.   28. The catalyst substrate according to any one of claims 1 to 27, further comprising an oxygen storage oxide.   29. The catalyst substrate according to any one of claims 1 to 28, which produces a pressure drop that is lower than the pressure drop caused by cordierite.   A catalytic converter comprising the catalyst substrate according to any one of claims 1 to 29.   31. A catalytic converter according to claim 30 suitable for use in a commercial vehicle.   32. The catalytic converter of claim 31 selected from the group consisting of a main catalytic converter, a pre-catalytic converter, a post-catalytic converter or a mani-catalytic converter.   A particle filter comprising the catalyst substrate or the filtration substrate according to any one of claims 1 to 29.   34. The particle filter of claim 33, wherein the particle filter is a diesel particle filter.   35. A method of catalyzing a reaction comprising exposing one or more fluid streams to a catalytic substrate or catalytic converter according to any one of claims 1-32.   36. The method of catalyzing a reaction according to claim 35, wherein the fluid is exhaust gas from an internal combustion engine.   38. The method of catalyzing a reaction according to claim 36, wherein the exhaust gas comprises one or more of six reference pollutants.   35. A method of filtering a gas comprising exposing one or more fluid streams to a filtration substrate, catalyst substrate, particle filter or catalytic converter according to any one of claims 1-34.   39. A method for filtering gas according to claim 38, wherein the fluid is exhaust gas from an internal combustion engine.   40. The method of filtering gas according to claim 39, wherein the exhaust gas includes one or more of six reference contaminants.   A method for producing a catalyst substrate or a filtration substrate according to any one of claims 1 to 29, wherein a plurality of refractory silica fibers, refractory alumina fibers and refractory aluminoborosilicate fibers are heated. Mixing the fibers; washing the fibers; optionally chopping the fibers into one or more lengths; blending or mixing the chopped fibers into a slurry; preferably Adjusting the viscosity of the slurry by adding a thickener; adding a dispersant; adding the slurry to the mold; removing water from the slurry, thereby forming a green billet Removing the green billet from the mold; drying the green billet in a furnace, preferably at a temperature of about 250 ° F. to about 500 ° F .; about 2,000 Heating the green billet in a 2500 ° F. furnace, preferably preheating and incrementally heating; optionally machining the billet; optionally, a plurality of grooves in the billet Forming a catalyst substrate, optionally adding a catalyst; and optionally adding a washcoat, thereby forming the substrate.   The method includes machining a plurality of grooves in a nonwoven sintered refractory fibrous ceramic composite, wherein the machining includes using a combing method to form or shape the grooves. The method to manufacture the filtration base material as described in any one of 1-29.   44. A filtration substrate prepared according to the method of claim 42 or 43.   A composition comprising fireproof grade alumina fiber, fireproof grade silica fiber, fireproof grade alumina boria silica fiber, water and catalyst.   45. The composition of claim 44, wherein the fibers have an average length of about 10 [mu] m.   45. The composition of claim 44, wherein the alumina comprises about 50-90% of the inorganic fiber mixture; the alumina fiber comprises about 5-50% of the inorganic fiber mixture; and alumina boria silica comprises about 10-25%. . An improved engine exhaust system comprising the catalyst substrate, filtration substrate, catalytic converter or particle filter according to any one of claims 1 to 34.

Images