MXPA98001315A - Exhaust multiple with integral catalytic converter - Google Patents

Abstract

An exhaust manifold reducing pollutant (10 ') is described for an internal combustion engine incorporating a catalytic converter therein. The manifold (10 ') has a plurality of head pipes connected to and receiving gases from the respective ones of a plurality of exhaust ports of an internal combustion engine. The head pipes (22) are connected to an individual chamber (24) with an outlet thereof connected to an exhaust pipe (16), as well as a catalytic converter structure having a catalyst disposed on a support substrate (26) arranged in the chamber (24) between the inlet (s) (28) and the outlet (30), so that all exhaust gases from the engine must pass through the catalytic converter structure. The catalytic converter operates at higher temperatures for increased efficiency and reaches operating temperature virtually immediately, unlike existing converters. As a result, the amount of pollutants released into the atmosphere from the mot

Description

MULTIPLE ESCAPE WITH INTEGRAL CATALYTIC CONVERTER BACKGROUND OF THE INVENTION TECHNICAL FIELD: This invention relates to methods and apparatuses for removing contaminants from the exhaust emissions of internal combustion engines and, more particularly, to an exhaust manifold for reducing pollutants for an internal combustion engine, comprising, a plurality of of head pipes connected to and receiving exhaust gases from one of the respective plurality of motor ports; a catalytic chamber having an inlet (s) connected to receive exhaust gases from the plurality of head pipes and an outlet thereof connected to an exhaust system; and, a catalytic converter structure having a catalyst disposed on a supporting substrate disposed in the catalytic chamber between the inlet (s) and the outlet, so that all exhaust gases from the engine must pass through. of the catalytic converter structure.

BACKGROUND OF THE INVENTION: For many years, the exhaust systems of automobiles and other vehicles driven by internal combustion engines have remained substantially unchanged. There is an exhaust manifold that collects the exhaust gases emitted from the exhaust ports of the engine and expels them into an exhaust pipe, which leads the gases to the rear of the car. Typically, a muffler is arranged in line with the exhaust pipe to dampen the sounds of the gases to an acceptable level. More recently (after 1974 in the United States of America), modern exhaust systems have included a catalytic converter to remove the pollutants emitted from the exhaust gases. A typical prior art exhaust system of said design is illustrated in Figure 1. The exhaust manifold 10 is secured with bolts or fastened to the engine (not shown) with the flanges 12. The catalytic converter 14 is placed in line in the exhaust pipe 16, typically 0.6096 to 3.048 meters from the manifold 10. 18 muffler is typically placed on the back of the exhaust system. The above-described placement of the catalytic converter 14 creates several problems completely contrary to its intent, which is to reduce the contaminants. Once it is operational, it works absolutely well for its intended use. However, because of its placement, it does not work as well as it could, in addition, until it reaches its operating temperature, it does not work well at all. A catalytic converter is nothing more than a catalyst arranged on a substrate. When sufficiently hot, the catalyst causes the unburned contaminants to be oxidized further. Until then, the pollutants pass through the unaffected ones. Since it is placed below the exhaust pipe 16, when the engine is turned on, the catalytic converter 14 cools. And, it takes time for the heat to develop in the catalytic converter 14 at a sufficient level that it starts to work. Unfortunately, ignition is the time when most contaminants are produced, since a choke or similar mechanism typically increases the fuel to air ratio to improve the combustion process in a cold engine. Thus, partially burned fuel products pass virtually unimpeded into the atmosphere. When one considers the number of engines ignited in a cold condition in a large city on a normal day, it can be seen that there are many unburned pollutants emptied into the atmosphere on a daily basis. It has been suggested to add a heating element to the catalytic converter so that it reaches its operating temperature more quickly; But, this is a stop-gap measure that is not overly effective. Typically, an operator expects his vehicle to turn on immediately when the ignition key is turned on and will oppose if he has to wait until the catalytic convert heats up before the engine turns on. Like the bell or other alarm that warns that the safety belt is not in placeIf a car does not turn on until the catalytic converter reaches the temperature, based on human nature and previous experience, many drivers will simply have to modify their vehicles to pass that aspect, thus eliminating the results that are intended to be obtained. Therefore, it is an object of the present invention to provide a catalytic converter, which starts the effective operation virtually immediately. It is another object of the present invention to provide a catalytic converter, which is highly effective in removing contaminants from the exhaust gases. Other objects and benefits of this invention will become apparent from the following description after it is read together with the accompanying drawings.

DESCRIPTION OF THE INVENTION The above objects have been achieved in an exhaust manifold for an internal combustion engine having a plurality of head pipes connected to and receiving exhaust gases from one of the respective ones of a plurality of engine exhaust ports and an inlet (s) of individual chamber connected to the plurality of head pipes and an outlet connected to an exhaust system, through the improvement of the present invention to reduce pollutants emitted by the engine, comprising arranging a catalytic chamber between the inlet (s) ) and the outlet thereof and provide a catalytic converter structure having a catalyst arranged on a supporting substrate in the catalytic chamber between the inlet (s) and the outlet, so that all exhaust gases from the engine They must pass through the catalytic converter structure. Preferably, the plurality of head pipes and the catalytic chamber are of a structural fiber reinforced ceramic matrix composite (FRCMC) comprising fibers of a generic fiber system disposed through a pre-ceramic resin in its state of pottery The preferred pre-ceramic resin comprises either a polymer-derived ceramic resin such as silicon-carboxyl resins or alumina silicate or a cement resin that has been modified to emulate polymer composite material processing techniques such as resin. of monoaluminum phosphate (aka monoaluminum phosphate); and, the generic fiber system comprises alumina, Altex, Nextel 312, Nextel 440, Nextel 510, Nextel 550, silicon nitride, silicon carbide, HPZ, graphite, carbon and peat. The preferred support substrate is an open-cell silicon carbide foam, silicon-carboxyl foam, ceramic oxide foam, or a similar ceramic foam material.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a simplified drawing of the components of the prior art exhaust system employing a catalytic converter.

Figure 2 is a partially cut-away, simplified drawing of an exhaust manifold according to the present invention incorporating a catalytic converter therein.

BEST MODE FOR CARRYING OUT THE INVENTION In a co-pending application entitled FIBER REI N FORCED CERAMIC MATRIX COMPOSITE I NTERNAL COM BUSTIÓN ENG INE EXHAU ST MANIFOLD, series number PCT / US96 / 1 1794, presented on the date with it, a composite material of ceramic matrix is described reinforced structural fiber improved that has a high resistance to rupture, a high resistance to temperature, resistance to corrosion, rejection of low heat content, and characteristics of thermal expansion "that can be disinfected", which make it particularly suitable for an exhaust manifold material for an internal combustion engine. This co-pending application for a method for forming automotive parts of fiber reinforced ceramic matrix composite (FRCMC) using a resin transfer molding technique (RTM) as described in a second co-pending application entitled METHODS AN D APPARATUS FOR MAKI NG CERAM IC MATRIX COMPOSITE LI N ED AUTOMOTIVE PARTS AND FI BER REI FORCED CERAMIC MATRIX COMPOSITE AUTOMOTIVE PARTS, series number PCT / US96 / 1 1772, also presented with the same. The general RTM method described in the second co-pending request mentioned above, included in the first step forming a configured preform of a generic fiber system to be used. Then it is inserted into a preform mold and the mold is sealed. In the preferred aspect, the generic fiber system occupies from 30% to approximately 60% of the internal volume of the mold. As an alternative, but not preferred, aspect, the mold can be filled with shredded generic fiber at the same packing density by volume. A pre-ceramic polymer resin is then forced through the fibers to fill the remaining internal volume of the mold. The resin referred to is the pre-ceramic polymer previously described, the Si-carboxyl resin sold by Allied Signal under the trade name of Blackglas. This is due to its low viscosity, which allows it to be forced through and saturated at a high bulk density of the generic fiber preform. The more rigorous the density, the stronger the part will be. Thus, to use a higher viscosity resin, the packing density of the fibers could be greatly reduced, resulting in a corresponding reduction in the strength of the part. The preform impregnated with resin inside the mold is then heated at a level and for a time sufficient to polymerize the resin, saturating the fiber preform. The preform later is like an unglazed ceramic, so it does not have its full strength, but it could be handled. The polymer preform is removed from the mold and then ignited at a temperature and for a time such as those established by the resin manufacturer in order to make the polymer a ceramic. The part or liner in its basic form is thus formed as a ceramic matrix composite material preferably having approximately 50-60% by volume of the fiber content therein. The ignition procedure, which turns the polymer into ceramic, causes the formation of pores due to degassing, which occurs during the ignition procedure. The resulting ceramic part is approximately 70% solid and 30% pores formed by degassing. In this regard, it looks a lot like the monolithic pottery previously used to line auto parts. The parts of matter composed of fiber-reinforced ceramic matrix are, of course, much stronger than the monolithic parts, due to the high fiber content. However, the same technique can be used to make the parts even stronger. The ceramic preform is immersed in Blackglas liquid resin (or equivalent). The viscosity of the resin, similar to that of water, causes it to fill 30% of the pores in the part. The part is then turned on once more during the time and at the temperature indicated by the manufacturer of the resin. This causes the resin, within 30% of the pores, to be converted to ceramics. But, the ignition procedure means that 30% of the 30% of the volume is degassed. Thus, the part is once again submerged in the liquid resin and ignited for a third time. This procedure can be repeated until a desired level of pore removal is achieved. The resulting part is approximately 95% -98% of ceramics and fibers with non-degassed pores. Thus, it is its maximum resistance. The first co-pending request mentioned above describes a specific method for manufacturing an exhaust manifold of FRCMC, using the RTM method described above, which includes the following steps: 1. Extending a pair of halves multiple (upper and lower halves) to join a final step or a total manifold fiber mat woven fabric, such as, but not limited to, alumina, Altex, Nextel 312, Nextel 440, Nextel 510, Nextel 550, silicon nitride, silicon carbide, H PZ, graphite, carbon, and peat. 2. The halves of the multiples are then applied a fiber contact surface coating as is the best practice in the industry. The assignee of this solitude, N orthrop Corporation, currently has a number of patents on the application for contact surface coatings, the teachings of which are incorporated herein by reference. Also, Allied-Signal or Sinterials are commercial companies, which will apply a contact surface coating as a purchased service. 3.- The halves of the manifolds or the total manifold are then saturated with resin, in this example being the Blackglas resin. This step may also include compressing the resin mixture Ceramic-derived polymer and fibers coated with the contact surface material of a generic fiber system under pressure to a mold to form the multiple-shaped structure. 4. The multiple halves saturated with resin or the total manifold are then heated by the following cycle: A) Ambient ramp at 65.5 ° C to 2.7 ° / minute B) Maintain at 65.5 ° C for 30 minutes C) Ramp to 1 .7 ° / minute to 148.8 ° CD) Maintain at 148.8 ° C for 60 minutes E) Cool at 1 .2 ° / minute until the temperature is below 60 ° C It should be noted that there is a variety of warming cycle defi nitions, which will create usable hardware and the foregoing is only by way of example, and is not intended to be exclusive. 5. If the halves of the manifolds are made, they are set or adjusted by jumping together along coinciding edges at this point to form a total manifold. The two pieces now fixed together, are immersed in Blackglas resin for a minimum of five minutes. The part is then removed from the resin and heated as in the previous ramp rate to keep the edges together. 6. The multiple of polymer composite material is then polymerized. In this regard, the manufacture of a sealable container, such as a stainless steel box, capable of withstanding 1037.7 ° C, is required for the pyrolysis cycle in a normal furnace. In the alternative, if available, an inert gas oven can be used. The box must have two pipe connections, one on the bottom and one on top to allow the box to be flooded with inert gas. In this example, the manifold is placed in the box, the box is placed in a normal oven, the stainless steel pipe is connected to the lower connector on the box and to a supply of high purity argon. Of course, any equivalent inert gas can be used. The argon is let flow into the box, and out through the upper ventilation at a speed of 141.58-283.16 liters / hour for the entire heating cycle, thus ensuring that the manifold is fully wrapped in an inert environment. The furnace is closed and ignited with the following base: A) Ramp at 148.8 ° C at 223 ° / hour B) Ramp at 482.2 ° C at 43 ° C / hour C) Ramp at 760 ° C at 20 ° C / hour D) Ramp at 871 .1 ° C at 50 ° / hour E) Keep at 871 .1 ° C for 4 hours F) Ramp at 25 ° C at - 125 ° / hour Again, there is a variety of heating levels different from this, given only by way of example, which will produce usable hardware. 7. After cooling, the manifold is removed from the oven and the box and immersed in a Blackglas resin bath for a sufficient time to allow air to be removed from the manifold (typically 5 minutes or more). You can also use vacuum infiltration for this step. This fills any pores in the FRCMC manifold with resin. 8. Steps 6 and 7 are then repeated until the remaining degassed pores are below the desired level, which imparts maximum resistance to the final FRCMC manifold. Typically, it is preferred that this cycle be repeated five times. The manifold is now ready to be used.

The present invention is intended to be particularly used with the multiple design described above, as a catalyst converter substrate can be co-cured with the same manifold. Additionally, in the invention of the ceramic manifold, an expandable mandrel is used to form the internal contours of the FRCMC exhaust structure and, as described therein, employing the present invention described herein, the expandable mandrel can be removed and replaced by the catalytic converter substrate material, which acts as an internal tool during the formation procedure of the FRCMC manifold structure. As illustrated in Figure 2, in the present invention the catalytic converter substrate material 14 'is incorporated directly into the exhaust manifold 10'. The head pipes 22, the chamber 24, and the individual connecting pipe 28 all contain the catalytic substrate and, therefore, act as the catalytic converter chamber. The outlet 30 is the outlet of the manifold 10 ', to which the normal exhaust pipe 16 of Figure 1 is connected. Thus, all the hot exhaust gases from the engine immediately collide and pass through the catalytic substrate 26 to be cleaned therefrom. Not only are the gases hotter than in the conventional prior art catalytic converter; rather, in addition, the catalytic substrate 26 of this invention achieves a sufficient operating temperature almost immediately due to the insulation / heat-holding effect of the external FRCMC structure which is an inherently low thermal conductivity and a low specific thermal capacity. Since any structure capable of withstanding the temperatures involved can be employed for the multiple 10 'of this invention, the entire ceramic structure, as described in the first co-pending application mentioned above, is preferred. Thus, it is preferred that the head pipes 22, the chamber 24, the connecting pipe 28 and the outlet 30 are made of a fiber reinforced ceramic matrix composite (FRCMC) comprising a pre-ceramic resin having fibers. of a generic fiber system arranged through it. The preferred FRCMC material used in the present invention includes either commercially available polymer-derived ceramic resins, such as the silicon-carboxyl resin (sold by Allied-Signal, under the trade name of Blackglas), alumina silicate resin (sold by Applied Poleramics under the designation of CO2 product) or cement resins that have been modified to emulate the techniques of polymer composite material processing, such as monoaluminium phosphate resin (also known as monoaluminium phosphate) combined with a generic fiber system such as, but not limited to, alumina, Altex, Nextel 312, Nextel 440, Nextel 510, Nextel 550, silicon nitride, silicon carbide, H PZ, g raphite, carbon and peat. To increase the tenacity qualities of the material, the fiber system is first coated a few microns thick with a contact surface material such as carbon, silicon nitride, silicon carbide, silicon carbide, boron nitride or layers. multiple of one or more of these contact surface materials. The contact surface material prevents the resin from adhering directly to the fibers of the fiber system. Thus, after the resin has been converted to a ceramic as per the cure cycle recommended by the resin manufacturer, there is a weak contact surface between the ceramic matrix and the fibers, thus imparting the desired capabilities to the final component . In addition, since any type of structure capable of withstanding the temperatures involved can be employed for the catalytic converter substrate 26, a high temperature resistant foam structure, such as silicon carbide, silicon-carboxyl, or a ceramic foam of equivalent oxide, is preferred due to its high ratio of surface area to volume and low specific thermal capacity.

Claims (9)

1 . - An exhaust manifold for reducing pollutants for an internal combustion engine, comprising: a) a plurality of head pipes connected to and receiving exhaust gases from the respective ones of a plurality of exhaust ports of the engine; b) a catalytic chamber having an inlet connected to receive exhaust gases from the plurality of head pipes and an outlet thereof connected to an exhaust pipe; c) a catalytic converter structure having a catalyst disposed on a supporting substrate in said catalytic chamber between said at least one inlet and said outlet, so that all the exhaust gases from the engine must pass through said structure of said catalytic converter. catalytic converter; and d) wherein said plurality of head pipes and said catalytic chamber are of a ceramic matrix composite material reinforced with structural fiber comprising fibers of a generic fiber system disposed through a pre-ceramic resin in its ceramic state .

2. The exhaust manifold for reducing contaminants according to claim 1, wherein: a) said pre-ceramic resin constitutes at least one of silicon-carboxyl resin, alumina silicate, and monoaluminium phosphate resin; and b) said fibers constitute at least one of alumina, Altex, Nextel 312, Nextel 440, Nextel 510, Nextel 550, silicon nitride, silicon carbide, HPZ, graphite, carbon, and peat.

3. The exhaust manifold to reduce contaminants according to claim 1, wherein: said catalyst support substrate is a high temperature resistant foam material.

4. The exhaust manifold for reducing pollutants according to claim 3, wherein: said foam material constitutes at least one of silicon carbide and silicon-carboxyl.

5. A method for maximizing the removal of unburnt contaminants from an internal combustion engine exhaust, comprising: a) receiving hot exhaust gases from a plurality of engine exhaust ports; b) immediately direct all hot exhaust gases to a chamber made of a ceramic matrix composite material reinforced with structural fiber comprising fibers from a generic fiber system disposed through a pre-ceramic resin in its ceramic state and connected to the exhaust ports and containing a catalyst on a substrate; and c) directing all hot exhaust gases over the catalyst and out of an individual outlet of the chamber to an exhaust system.

6. In an exhaust manifold for an internal combustion engine having a plurality of head pipes connected to and receiving exhaust gases from one of the respective of the plurality of exhaust ports of the engine and a single chamber connected to the plurality of head pipes and an outlet connected to an exhaust system, the improvement to reduce the pollutants emitted by the engine comprising: arranging a catalytic converter structure having a catalyst disposed on a supporting substrate in said catalytic chamber between the head pipes and said outlet, so that all exhaust gases from the engine must pass through said catalytic converter structure; and providing said plurality of head pipes and said catalytic chamber as a composite material of ceramic matrix reinforced with structural fiber comprising fibers of a generic fiber system disposed through a pre-ceramic resin in its ceramic state.

7. The improvement to an exhaust manifold according to claim 6, wherein: a) said pre-ceramic resin constitutes at least one of a silicon-carboxyl resin, alumina silicate resin, and resins of modified cement to emulate polymer composite material processing techniques including a monoaluminum phosphate resin; and b) said fibers constitute at least one of alumina, Altex, Nextel 312, Nextel 440, Nextel 510, Nextel 550, silicon nitride, silicon carbide, H PZ, graphite, carbon, and peat.

8. The improvement to an exhaust manifold according to claim 6, wherein: said support substrate is a ceramic material.

9. The improvement to an exhaust manifold according to claim 8, wherein said: said foam material constitutes at least one of silicon carbide, and silicon-carboxyl.