AU1831701A - A method and apparatus for reducing pollutants and contaminants in exhaust gases of an engine - Google Patents

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: a Name of Applicant: Litex, Inc.

Actual Inventor(s): Robert N Miller, Robert P Caren, Jack A Ekchian Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: A METHOD AND APPARATUS FOR REDUCING POLLUTANTS AND CONTAMINANTS IN EXHAUST GASES OF AN ENGINE Our Ref: 636369 POF Code: 1443/338992 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- 606q 1A A METHOD AND APPARATUS FOR REDUCING POLLUTANTS AND CONTAMINANTS IN EXHAUST GASES OF AN ENGINE This application is a divisional of Australian application 13479/97, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention: The present invention generally relates to a method and apparatus for reducing pollutants in the exhaust gases produced by the combustion of fuel. In one embodiment the invention provides a method and apparatus wherein the reduction in pollutants is achieved by the use of ozone. In a different embodiment the reduction in the concentration of pollutants is achieved by introducing hydroxyl radicals "OH" and other free radical intermediaries and oxidizers such as O, H, HO 2 and H 2 0 2 into the precombustion or postcombustion gases produced by the combustion of fuel.

2. Background: As is well understood in the art, an internal combustion engine draws in 20 ambient air which is mixed with fuel for combustion in a combustion chamber or cylinder and the resulting exhaust gases are expelled. Ignition of the air/fuel mixture in the cylinder is typically achieved by an ignition device, such as, for o example, a spark plug or the like, or adiabatic compression to a temperature above the fuel's ignition point.

25 In certain internal combustion engines, such as for example, gasoline engines commonly in use today, air is inducted via an air intake duct or port which conveys the ambient air to a carburetor or a fuel injection arrangement where the air is mixed with fuel to create an air/fuel mixture. The air/fuel mixture is then conveyed via an intake manifold to the combustion chamber or cylinder of the engine. In diesel-type engines and certain spark ignition engines such as those utilizing an in-cylinder fuel injection arrangement, the air and fuel are mixed in the combustion chamber or cylinder of the engine.

After the air/fuel mixture has been burnt, the resulting exhaust gases are expelled from the combustion chamber to an W:\ConnieXNODELETE\DJT'RPEChlockheeddi.doc WO 97/22794 PCT/US96/20581 exhaust manifold. The exhaust gases then may be conveyed via at least one exhaust pipe to the catalytic converter where pollutants are removed.

The flow of air to any combustion chamber, including the flow of the air/fuel mixture if applicable, is hereinafter referred to as the precombustion gas stream, and the r resulting flow of exhaust therefrom is hereinafter referred to as the postcombustion or exhaust gas stream. As used herein, the precombustion and postcombustion gas streams are hereinafter collectively referred to as the combustion gas stream.

Internal combustion engines, which operate by the controlled combustion of fuels, produce exhaust gases containing complete combustion products of carbon dioxide (CO2) and water (H 2 0) and also pollutants from incomplete combustion such as carbon monoxide which is a direct poison to human life, as well as unburnt hydrocarbons (HC).

Further, due to the very high temperatures produced by the burning of the hydrocarbon fuels followed by rapid cooling, 20 results in the detrimental formation of nitrogen oxide NO,, an additional pollutant.

The quantity of pollutants varies with many operating conditions of the engine but is influenced predominantly by the air-to-fuel ratio in the combustion cylinder such that conditions conducive to reducing carbon monoxide and unburnt •hydrocarbons (a fuel mixture just lean of stoichiometric and high combustion temperatures) cause an increased formation of NO, and conditions conducive to reducing the formation of NO, (fuel rich and fuel lean mixtures and low combustion 30 temperatures) cause an increase in CO and unburnt HC in the exhaust gases of the engine. Because in modern day catalytic converters NO, reduction is most effective in the absence of oxygen, while the abatement of CO and HC requires oxygen, preventing the production of these emissions requires that the engine be operated close to the stoichiometric air-tofuel ratio, because, under these conditions the use of threeway catalysts (TWC) are possible, all three pollutants 2 WO 97/22794 PCTIUS96/2058 can be reduced simultaneously. Nevertheless, during operation of the internal combustion engine, an environmentally significant amount of CO, HC and NO X is emitted into the atmosphere.

Although the presence of pollutants in the exhaust gases of internal combustion engines has been recognized since 1901, the need to control internal combustion engine emissions in the United States came with the passage of the Clean Air Act in 1970. Engine manufacturers have explored a wide variety of technologies to meet the requirements of the Clean Air Act. Catalysis has proven to be the most effective passive system.

Automobile manufacturers generally have employed catalytic converters to perform catalysis. The purpose is to oxidize CO and HC to CO, and H 2 0 and reduce NO/NO, to N 2 Auto emission catalytic converters are typically located at the underbody of the automobile and are situated in the exhaust gas stream from the engine, just before the muffler, which is an extremely hostile environment due to the extremes of 20 temperature as well as the structural and vibrational loads encountered under driving conditions.

Nearly all auto emission catalytic converters are housed in honeycomb monolithic structures which are generally made of cordierite, a low-thermal-expansion ceramic with excellent strength and crack resistance under thermal shock. The S honeycomb construction and the geometries chosen provide a relatively low pressure drop and a high geometric surface area which enhances the mass-transfer-controlled reactions.

The honeycomb is set in a steel container and protected from 30 vibration by a resilient matting.

An adherent washcoat, generally made of stabilized gamma alumina into which the catalytic components are incorporated, is deposited on the walls of the honeycomb. TWC technology for simultaneously converting all three pollutants comprises the use of precious (noble) metals Pt and Rh, with Rh being most responsible for the reduction of although it also contributes to CO oxidation along with Pt. Recently less 3 WO 97/22794 PCTIUS96/20581 expensive Pd has been substituted for or used in combination with Pt and Rh. The active catalyst contains generally about 0.1 to 0.15% precious metals, primarily platinum (Pt), palladium (Pd) or rhodium (Rh).

Because the exhaust gases of a combustion engine oscillates from slightly rich to slightly lean, an oxygen storage medium is added to the washcoat which adsorbs (stores) oxygen during the leanpart of the cycle and releases it to react with excess CO and HC during the rich portion. CeO 2 is most frequently used for this purpose due to its desirable reduction-oxidation response.

The recent passage of the 1990 amendment to the Clean Air Act requires further significant reductions in the amount of pollutants being released into the atmosphere by internal combustion engines. In order to comply with these requirements, restrictions on the use of automobiles and trucks have been proposed, such as, employer compelled car pooling, HOV lanes, increased use of mass transit as well as rail lines and similar actions limiting automobile and truck 20 usage at considerable cost and inconvenience.

An alternative to diminished automobile and truck usage is decreasing emissions by increasing the efficiency of the G to internal combustion engine. This will have limited effect because studies show that most of automobile originated pollution is contributed by only a small fraction of the vehicles on the road, these vehicles typically being older models having relatively inefficient engines and aging catalytic converters that inherently produce a lot of t o. pollution. Unless the increased efficiency is provided by a S 30 device which can be retrofitted at a reasonable cost, it is unlikely that such improvements will be added to other vehicles and thus fail to adequately solve the problem.

In addition, while considerable gains have been made in recent years to reduce the amount of pollutants in the exhaust gases of the internal combustion engine of vehicles such as automobiles and trucks, it is a considerable technological challenge and expensive to further reduce the 4 WO 97/22794 PCTIUS96/20581 amount of pollutants in the exhaust gases of the internal combustion engine, even though exhaust emissions of automobiles and trucks currently being manufactured do not meet proposed Environmental Protection Agency standards.

As a solution to increasing the efficiency of the internal combustion engine, it has been proposed in U.S.

Patent Nos. 1,333,836 and 1,725,661 to provide ozone producing apparatus in association with the air intake of the carburetor. Ozone, being a very efficient oxidizer, increases the completeness of combustion of fuel by the engine thereby reducing contaminants in automobile exhaust gases and also increasing efficiency. These above-noted, known arrangements for generating ozone are complicated as well as expensive and cannot be easily installed in a new engine during production nor easily retrofitted to an existing engine.

In U.S. Patent No. 4,195,606 to Wallis, Jr. et al.

combustion air for an internal engine is treated to activate the oxygen molecules prior to mixing it with the fuel by 20 photochemically activating the oxygen with ultraviolet radiation from a germicidal lamp at a frequency of about 2537 angstroms (253.7 nanometers). However, in the Wallis, Jr. et al. patent, no ozone is produced by the germicidal lamp as confirmed by the lamp manufacturer. Thus, Wallis et al.

stresses that the preferred range is 2000 to 3000 angstroms (200 to 300 nanometers) which does not include the 100-200 nanometer ozone generating wavelength of the ozone creating lamp of certain embodiments of the present invention. Above 200 nanometers ozone photodissociates so that even if ozone 30 is present its concentration would diminish when ultraviolet light having a wavelength above about 200 nanometers is used.

In lieu of decreasing exhaust emissions by increasing oooo the efficiency of the internal combustion engine or decreasing the use of automobiles, a further alternative would be to increase the efficiency of catalysis such as by the catalytic converter. The conversion efficiency of a catalytic converter is measured by the ratio of the rate of 5 6 mass removal of the particular constituent of interest to the mass flow rate of that constituent into the catalytic converter. The conversion efficiency of a catalytic converter is a function of many parameters including aging, temperature, stoichiometry, the presence of any catalysts' poisons (such as lead, sulfur, carbon, and phosphorous), the type of catalyst and the residence time of the exhaust gases in the catalytic converter.

Attempts to increase the efficiency of catalytic converters has not been sufficiently successful. While modern TWC catalytic converters help, they are expensive and there is still a significant amount of pollutants emitted into the atmosphere by the catalytically treated exhaust gases. These converters may have difficulty in meeting future emissions requirements and they have limitations in their performance lifetime. Catalytic converters also suffer from the disadvantage that their conversion efficiency is low until the system reaches operating temperature.

The above discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia 20 before the priority date of each claim of this application.

Throughout the description and claims of this specification, the word "comprise" and variations of the word, such as "comprising" and "comprises", is not intended to exclude other additives, integers or process steps.

SUMMARY OF THE INVENTION 25 It is a desired feature of the invention to provide a method and apparatus for reducing contaminants in automobile or truck exhaust gases which is inexpensive to employ and manufacture, simple in structure and operation as well as easily installed in new engine or retrofitted to existing vehicle engines.

A further desired feature of the invention is to provide a method and apparatus for reducing pollutants in W:Marlo\NODELETEDJTSPECI~ockheeddiv.doc the exhaust gases of an internal combustion engine having a catalytic converter by improving the conversion efficiency of the catalytic converter without the need for major modifications to the internal combustion engine or the catalytic converter.

A further advantageous feature is to provide a method and apparatus for reducing pollutants in the exhaust gases produced by an internal combustion engine having catalytically active material treating the exhaust gases.

A particularly advantageous feature of the invention is that it provides a relatively inexpensive way to reduce pollution by retrofitting those engine and catalyst combinations already on the road which contribute the most pollution and are most likely to fail an emission test as well as providing easy installation in new engine systems.

A further desired feature of the invention is that reduced emissions are achieved by adding hydroxyl radicals and other free radical intermediates and oxidizers such as O, H, HO 2 and H 2 0 2 to modify the composition of the exhaust gases without the need to store special chemical additives onboard.

6i

O

*0 NY2- 1139669.1 8 Yet another advantageous feature of the invention is that it can be applied to a variety of different types of internal combustion engines, including, but not limited to, gas turbine engines as well as reciprocating engines including automobiles, trucks, stationary power generators, motorboats, motorcycles, motorbikes, lawn mowers, chain saws or leaf blowers which may use a variety of different fuels such as gasoline, gasoline-based formulations, diesel fuel, alcohol, natural gas and any other fuel where a catalytic converter can be used to reduce the concentration of at least one pollutant. In addition, the invention cannot only be retrofitted to existing engines but also incorporated into newly designed engines.

In accordance with the invention, there is provided an apparatus for reducing pollutants from the combustion of a fuel, the apparatus comprising: a combustion chamber having a precombustion gas stream to the combustion chamber and a post combustion gas stream of exhaust from the combustion chamber; a large surface area receptacle located in the postcombustion gas stream; and a0a device for adding hydroxyl radicals to at least one of the precombustion gas stream and the postcombustion gas stream before the termination of the 20 large surface area receptacle.

In a further embodiment of the invention there is provided a method for treating exhaust gases to reduce at least one pollutant from incomplete combustion of fuel in a combustion chamber having a precombustion gas stream of at least air to, and a postcombustion gas stream of exhaust gases from, the method comprising: adding hydroxyl radicals to at least one of the precombustion and postcombustion gas streams; and providing sufficient surface area in a postcombustion chamber to allow the hydroxyl radicals to react with the exhaust gases produced from the combustion of the fuel.

W:xMaloNODELETEDJTSPECoceeddiv.doc 9 It is believed that hydroxyl radical "OH" and other free radicals and oxidizers such as O, H, HO 2 and H 2 0 2 can be introduced into the combustion gas stream of a combustion engine to reduce pollutants and contaminants such as CO and HC. It has been observed that OH in the presence of oxygen can react rapidly with CO to produce CO 2 It has also been observed that OH in the presence of oxygen can react rapidly with hydrocarbons (HC) to produce formaldehyde or other similar intermediary products which then further react with OH to form H 2 0, C02, and OH. Moreover, there is evidence that the series of reactions does not consume, but rather regenerates OH.

In the case of CO, the following reaction steps convert CO to CO 2 and regenerate OH: CO OH CO2 H H 02

HO

2

HO

2 hv OH O The latter process of dissociation of hydroperoxyl to hydroxyl can take place either via the absorption of ultraviolet photon or by thermal 15 decomposition.

In the case of HC, a typical reaction set may involve the following steps: HC OH HCHO HCHO OH H 2 0 HCO HCO 0 2 C0 2

HO

W:WaroNODELETEXDJT\SPECJockheddiv.doc WO 97/22794 PCT/US96/20581 Depending upon the HC species, there may be branching reactions and other free radical intermediaries and oxidizers such as 0, H, HO 2 and H 2 0 2 may be produced and either enter into the reactions directly or through the products of other reactions such as: 0 02 03, or

H

2 0 2 hv Particularly important in the hydroxyl embodiment of the invention is that OH is believed to be regenerated in the course of the reactions, it acts as a catalyst, and that the reaction sequence proceeds rapidly due to the strong nature of the free radical reactions.

It is believed that the presence of OH, and other free radical intermediates and oxidizers such as 0, H, H,0 2 and HO 2 in the exhaust gases of a combustion engine leads, in the presence of requisite oxygen, to a very effective catalytic destruction of CO.and hydrocarbons to non-polluting gas species CO, and water vapor. The OH and other related free radicals and oxidizers created in the reactions can act as a 20 catalyst independent of or in conjunction with the normal *i catalytic function of the precious metal particles (Pt, Pd, Rh and combinations thereof) in the catalytic converter.

It is believed that the injection of OH into the combustion gas stream results in rapid catalyzing of CO and HC reactions in the exhaust gas flow stream. The reactivity of OH is believed to cause much of the catalytic activity associated with the conversion of CO to CO, and hydrocarbon to

CO

2 and H 2 0 to take place in the gas phase and on the large S" surface area of the washcoat surface of the catalytic 30 converter. Thus, within a limited region near the entrance of the catalytic converter, the bulk of the reactions converting CO and HC to CO and H 2 0 occurs. Because CO and the HC are oxidized in the gas phase and in the washcoat of the catalytic converter, with resulting substantial completion of the oxidation of CO and HC near the entrance to the catalytic converter, the bulk of the precious metal 10 WO 97/22794 PCT/US96/20581 catalytic surface is freed from participating in these competing reactions. For example, the converter's precious metal sites no longer need to catalyze the less reactive hydrocarbon species such as methane, ethane, ethene, benzene and formaldehyde. As a result, more effective catalytic activity at the precious metal sites can be directed toward reduction of nitrogen oxides to nitrogen and other nonpolluting gas species.

It is believed that the action of the hydroxyl can take place over the volume of the exhaust gas and the entire surface area of the catalytic converter, over the entire, large area of the washcoat. This makes for a much larger effective pollutant reduction action over the catalytic converter operating in the conventional manner.

Under this new mode of catalytic conversion operation, nitrogen oxide reduction can diminish below conventional baselines. Alternatively, less precious metal content, or the use of less costly metals or their oxides can be used to reduce the nitrogen oxide compounds below allowable emission 20 limits.

Several different modes of operation and devices may be ~utilized to carry out the hydroxyl embodiment of the invention. In one embodiment, OH is produced in a generator "i using mercury (Hg) vapor lamp radiation and atmospheric air intake which is conditioned to be of sufficiently high water vapor content, and preferably to about 100% saturation. It is believed that in air of high water vapor content there are two alternative competing reaction branches for creating OH.

In the first case, there is direct photodissociation of the S. 30 water into OH and H by the absorption of 185 nanometer ("nm 1 photons. To achieve such high humidity, the water vapor can come from a heated water source or it can be supplied from the exhaust gas stream of the engine. The other reaction, which is favored at a lower, but still sufficiently high, water vapor content, is that the 185 nm UV radiation from the lamp acts on the air to produce atomic oxygen and ozone The ozone is created by a three-body reaction involving 11- WO 97/22794 PCT/US96/20581 atomic oxygen, molecular oxygen and any other molecular constituent of air, such as, for example, Nitrogen

(N

2 Oxygen Water (HO) or Argon. The 253.7 nm UV radiation breaks down the ozone by photodissociation into molecular oxygen 02 and a metastable oxygen atom If the air stream entering the generator has sufficient water vapor content, then it is believed the metastable atomic oxygen combines with. water molecules to form hydrogen peroxide: 0 H 2 0 H 2 0 2 Further, the 253.7 nm UV radiation photodissociates the hydrogen peroxide into two hydroxyl molecules.

The generator thus injects ozone, atomic oxygen, hydrogen peroxide, and hydroxyl into the engine via, for example, the intake manifold. It is believed that any hydrogen peroxide so injected will dissociate into hydroxyl under the high engine temperature. The hydroxyl which resides in the crevice regions of the combustion chamber should survive the combustion process in the engine and act upon the CO and HC remaining in the exhaust stream to produce 20 CO 2 and H 2 0 according to the reactions described above.

i* A further embodiment of hydroxyl generation is to feed a S* water vapor-rich input air stream into a glow discharge generator (a generator in which a glow discharge occurs in water vapor primarily or only). Another approach is an overvoltage electrolysis cell to generate ozone in addition to oxygen and water vapor, followed by 200-300 nm UV exposure to create atomic oxygen by photodecomposition which in the presence of a water vapor-rich input air stream initiates e hydrogen peroxide creation, followed by hydroxyl generation S 30 via UV dissociation of the hydrogen peroxide. This latter device can be very compact using a mercury vapor lamp as the UV source due to the high efficiency of the output at 253.7 nm and the high absorbability of ozone and hydrogen peroxide for UV light of this wavelength.

The foregoing embodiments principally involve hydroxyl generators injecting their streams of output gases into the intake manifold region of the engines. A natural advantage -12of such methods is that the low pressure condition in regions of the intake manifold provides a natural pumping mechanism.

However, a drawback of these methods is that most of the highly chemically active species, including the free radicals such as hydroxyl, are destroyed in the combustion process and only those active species in the crevice regions and at the walls of the combustion chamber can effectively survive and enter into the exhaust gas stream where they are useful in oxidizing CO and HC. In contrast, generators which inject hydroxyl radical directly into or which create hydroxyl in the exhaust (postcombustion) gas stream can more effectively deliver the active species into the exhaust gas stream where CO and HC need to be oxidized. Thus, less chemically active species source strength would be required for equivalent emission reduction. This should translate directly into proportionally lower electrical input demands for the hydroxyl generator.

However, because of the higher pressures in the exhaust gas stream, pumping is required to accomplish direct injection of the generator output into the exhaust gas Vo.000 stream. The use of a venturi will assist this process.

Alternatively, because of the high vapor pressure of water at temperatures above approximately 120 C, using a water vapor discharge source in the hydroxyl generator can also provide effective injection. Such water vapor can be collected by condensation or equivalent means from the exhaust gas stream.

An embodiment creating hydroxyl in the exhaust gas stream is the irradiation of the exhaust gas stream with UV radiation in the about 120 to 185 nm wavelength range which in the presence of sufficient water vapor produces catalytically active OH by direct photodissociation. A still further embodiment is the use of UV radiation in the 120 to 185 nm wavelength in an external generator using atmospheric air intake and water vapor collected from the exhaust gas stream and injecting water vapor, OH and H into the exhaust gas stream prior to or in the catalytic converter.

13- 1WO 97/22794 PCT/US96/20581 The means described above for creation of these free radical species include ultraviolet light-based generators, glow discharge generators, and overvoltage electrolytic cells plus UV radiation. Generator inputs can include electricity, water, air, oxygen, water vapor, water vapor plus air and water vapor plus oxygen.

Modes of possible introduction of the above species into the engine system include into the precombustion gas stream, such as the intake manifold, into the exhaust gas stream such as the exhaust manifold, and into the catalytic converter.

The generators can be external or internal to these areas. A particularly advantageous feature of the external generator is that it provides the flexibility of installing the generator at a convenient location in the engine compartment or elsewhere on the vehicle. Another advantageous feature of the external generator embodiment is that the hydroxyl could be introduced at almost any desirable point in the intake (precombustion) or exhaust (post combustion) gas streams of the engine. A further advantageous feature of this 20 embodiment is that the flow rate of hydroxyl from the hydroxyl generator is independent of engine speed, flow of air to the combustion chamber or flow of exhaust gases from the combustion chamber. Thus, at low engine speeds, the mass flow rate of hydroxyl will not be affected by low air mass flow through the combustion chamber. For external sources, means of pumping of the generator gas products can include natural low pressure areas in the engine, introduction of ventri regions, external pumps, or natural generator pressurization as with higher temperatures and a.o.

30 water vapor sources.

Thus, this embodiment of the invention employs hydroxyl and its associated reaction species, 0, H, H20), and HO 2 to provide a catalytic cycle With OH playing the central role in reducing the CO and HC outputs of engines to meet present and future Ultra Low Emissions Vehicle "ULEV" and Low Emissions Vehicle "LEV" standards. Because the OH acts as a catalyst, relatively small amounts of OH need to be injected for orders 4- WO 97/22794 PCT/1S96/20581 of magnitude more CO and hydrocarbons to be reduced to CO 2 and

H

2 0O in the presence of oxygen in the exhaust gas stream.

It is believed that a further advantageous feature of the hydroxyl embodiment of the invention is that due to the introduction of gas-phase catalyst species, whose activities occur over the whole catalytic converter surface, and the inherent reactivity of these species, much earlier catalytic conversion of CO and unburned HC will occur after engine start. In other words, the effective light-off delay time after engine start will be reduced as compared to the use of a typical catalytic converter.

In the case of combustion and other residential, commercial and industrial systems which have exhaust gas streams which contain volatile organic compounds (VOCs), but contain minimal or no nitrogen oxides such as from some industrial processes, there would be no need for the typical catalytic converter and certainly no need for a precious metal catalytic converter. This invention would provide for very low cost catalytic converter systems. In those 20 situations where only CO or HC and other VOCs are required to be oxidized, it is contemplated that a typical catalytic :converter would not be required. However, it is contemplated that adequate time and/or a large surface.area similar to that provided by the honeycomb structure of the typical catalytic converter would be necessary to allow the CO, HC and VOCs oxidation reactions to take place.

.".These and other objects, advantages and features of the invention are achieved, according to one embodiment, by an apparatus comprising: 1) a combustion gas stream of an 30 engine, 2) a catalytic converter for treating the exhaust gases in the combustion gas stream to reduce further the amount of at least one pollutant from incomplete combustion of fuel and/or oxides of nitrogen, and 3) a device for adding OH and associated free radicals and oxidizers to the combustion gas stream upstream from or at the catalytic converter to reduce further the concentration of at least one 1 5 wNO 97/22794 PCT/US96/20581 pollutant in exhaust gases treated by the catalytic converter.

In accordance with the invention, a method is provided for treating exhaust gases to reduce the concentration at least one pollutant from incomplete combustion of a fuel having a precombustion gas stream of at least ambient air to the combustion chamber and a postcombustion gas stream of exhaust gases from the combustion chamber, the method comprising the steps of: adding hydroxyl and associated free radicals and oxidizers to at least one of the precombustion and the postcombustion gas streams and providing sufficient surface area in the postcombustion gas stream to allow the hydroxyl to treat the exhaust gases produced from the combustion of the fuel to reduce the concentration of at least one pollutant from combustion.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side perspective view of a known configuration of an internal combustion engine having a 20 catalytic converter: Figure 2 is a side view, partially in section, of one embodiment of the apparatus of the present invention; Figure 3 is a block diagram illustrating alternative embodiments of the invention wherein a plurality of ozone generating lamps are successively turned on at different and increasing predetermined engine loads or engine speeds; Figure 4 is a front view, partially-in-section, illustrating further arrangements of the apparatus of Figure 2; Figure 5 is a block diagram illustrating other embodiments of the apparatus of the invention wherein a device for adding ozone is positioned remotely of the precombustion and postcombustion gas streams and ozone enriched air is piped into the combustion gas stream; and Figure 6 is a block diagram illustrating the method of one embodiment of the invention.

16- WO 97/22794 PCT/US96/20581 Figure 7 is a side view, partially-in-section, illustrating one embodiment of the apparatus of the invention wherein a hydroxyl generating device is inserted into the precombustion gas stream; Figure 8 is a block diagram illustrating another embodiment of the apparatus of the invention wherein the device for adding hydroxyl is positioned remotely of the precombustion and postcombustion gas streams and hydroxyl enriched air is piped into the combustion gas stream; Figure 9 is a schematic diagram showing a hydroxylgenerating system according to one embodiment of the invention; Figure 10 is schematic diagram showing an alternative hydroxyl-generating system according to a different embodiment of the invention; Figure 11 is a schematic diagram of a hydroxyl generator according to a further embodiment of the invention; Figure 12 is a block diagram illustrating the method of the hydroxyl embodiment of the invention; and 20 Figure 13 is a block diagram illustrating the method of the present invention.

.5 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) Referring to Figure 1, a known configuration of an automobile engine 10 having a catalytic converter 13 is illustrated. The catalytic converter 13 is positioned at the underbody of an automobile (not shown) and is situated in the exhaust gas stream (postcombustion gas stream) A from the engine, downstream from the exhaust manifold 15 and just before the muffler 17.

The catalytic converter 13, as contemplated for use in the present invention, includes any device which is provided for treating exhaust gases from the combustion of a fuel, such as, for example, gasoline, gasoline-based formulations, diesel fuel, alcohol, natural gas and any other fuel where a catalytic converter can be used to reduce at least one pollutant from combustion, such as, for example, CO, and 17- WVO 97/22794 PCT/US96/20581 unburnt hydrocarbons and/or N0o, including, but not limited to, a three way catalyst typically used in today's modern automobile engines.

The catalytic converter 13 comprises, therefore, any device which catalytically removes or participates in the removal of at least one pollutant from an exhaust stream generated by combusting a fuel, including, but not limited to, those with monolithic or granular ceramic substrates, metallic substrates, or substrates of any kind, and devices with noble (precious) metals or any other type of catalytic material. It would also include, without limitation, devices having semiconductor catalysts, such as, oxides or sulphides of transition elements, and devices having ceramic type catalysts, such as alumina, silica-alumina, and zeolites individually, in combination with each other and oxygen storage media such as cerium oxide or in combination with metal catalysts.

Figure 2 illustrates one embodiment of an apparatus 11 of the present invention. The apparatus 11 comprises a device for generating ozone such as an ultraviolet light

S

emitting lamp 21, for example, a mercury vapor arc lamp emitting ultraviolet light at about 100-200 nanometers. The

S..

lamp has an envelope of glass for transmitting ultraviolet light having a wavelength of about 100-200 nanometers because this emission is capable of producing ozone. The light transmitting envelope may be fused silica, or its equivalent 6060 synthetic quartz, supersil, sapphire or any other material S capable of transmitting ultraviolet light having a wavelength 0• oe of about 200 nanometers or lower. A source of fused silica 0555 lamps is GTE Products Corporation, Sylvania Lighting Center, o Danvers, Massachusetts 01923. Other UV generating lamps such.

as those containing neon, argon and combinations of these and other gases, for example mercury, may be used.

The lamp 21 is connected to a Bodine Model 12R25E/GS transformer 23 which converts 12 volt battery. power to the voltage and frequency required to operate the lamp 21. As shown in Figure 2, the transformer 23 can be connected to the -18- WO 97/22794 PCT/US96/20581 electrical system of an automobile by, for example, a plug 19 which is inserted into the cigarette lighter 20 of the automobile. This arrangement is particular attractive when retrofitting the apparatus 11 to an existing late model vehicle. Alternatively, the transformer 23 can be directly connected to the electrical system of the automobile by splicing into the hot wire (not shown) of the system, for example, as original equipment on a new vehicle.

In the apparatus 11 as illustrated by Figure 2, the lamp 21 is positioned upstream from the engine's carburetor, generally indicated at 31 in Figure i, for example, between an air filter 27 and air intake duct 29. However, the invention additionally contemplates positioning the device for generating ozone upstream from the air filter 29.

In order to retrofit the apparatus 11 to an existing engine 10, the air filter casing 24 is opened and the lamp 21 is placed between the air filter 27 and the air intake duct 29 and the electrical wire leads of the lamp 21 are placed so that they pass beneath the air filter cover (not shown) so that they are routed out of the casing 24, for example, between the casing 24 and its removable cover (not shown) for connection to the transformer 23.

~In order to increase the effective absorption coefficient of the oxygen in the air being inducted into the engine 10, the walls adjacent to the lamp 21 are provided with a surface highly reflective to ultraviolet light in the required range, for example, made of aluminum, in order to increase the mean free path of the 185 nanometer photons, since aluminum maintains its reflectance to ultraviolet light down to at least 185 nanometers.

However, if the lamp is too large to fit into this space, at least one hole 22 is drilled into the casing 24 holding the air filter 27 at the air intake duct 29. The hole 22, preferably positioned between the air filter 27 and the intake 29, has a diameter substantially equal to the diameter of the lamp 21. The lamp 21 is slid through the hole 22 into the interior of the casing 24 and is positioned 19 WO 97/22794 PCT/US96/20581 between the air filter 27 and air intake 29. A sealant, such as tape or caulking, is applied at the hole 22 so that little or no air can seep in through the hole 22 when occupied by the lamp 21. In lieu of the foregoing procedure requiring the formation of hole 22, a plurality of smaller length lamps 21a, 21b, as described hereinafter with particular reference to Figure 3, are used.

The transformer 23 is then fastened to a side panel 26 of the engine compartment of the vehicle by means of fasteners 28 such as screws or the like. The plug 19 is then inserted into the cigarette lighter 20 of the vehicle or alternatively, the transformer 23 is connected directly to the electrical system of the vehicle.

In order to assure that the lamp is operating, a photodetector or photo-detector/phospher 35 is located adjacent to the lamp 21 and connected to an indicator 37 which provides an indication when the photo-detector 35 fails to sense light energy from the lamp 21. The detector 35 and indicator 37 are not essential, however, such an option is recommended, especially if the invention is employed in lieu of known catalytic converters currently in use on automobiles and trucks rather than in combination with such catalytic converters.

"Table 1 compares the results obtained utilizing the ozone generating apparatus 11 which generates a trace amount of ozone and is situated in the precombustion gas stream, upstream from the carburetor or fuel injection system of an engine as illustrated in Figure 2. The results of the baseline test were conducted without the ozone generating apparatus 11. The engine tested was a 1990 Ford Taurus engine equipped with a production catalytic converter.

TABLE 1 BASELINE WITH OZONE REDUCTION CARBON MONOXIDE 0.28 0.02 92.8% HYDROCARBONS (ppm) 154 12 92.2% WO 97/22794 PCT/US96/20581 In addition, test vehicles have experienced an increase in gas mileage in the range of between 3 to 10% as well as an increase in power output. All.emission tests conducted to date show a small residual hydrocarbon content in the exhaust gases ranging from 4 to 12 parts per million (ppm).

The foregoing emission test results indicate that no ozone is passing through the engine without being utilized in the oxidation of the fuel. An Oriel Ozone Test Kit may be used to verify the absence of ozone. It consists of a hand operated pump and detector tube. The piston-type pump draws a sample of exhaust gas through the detector tube. The tube indicates the concentration of ozone by the length of color change in the tube. It measures the concentration of ozone in a range of 0.05 to 5 ppm.

If traces of ozone are detected in the exhaust gases, a control arrangement can be employed according to a further embodiment as shown in Figure 3 wherein a sensor 16 is installed. In this embodiment sensor 16 is in the exhaust pipe 12 and is adapted to detect the presence of ozone. The sensor 16 is connected to a controller 18 which switches off the ozone generating lamp 21 whenever ozone is detected in the exhaust gases and switched back on when no ozone is present. The controller 18 can be a simple switching arrangement such as, for example, a transistor or an S 25 electronic system which is controlled by the output of sensor 16 or as complex as an engine control computer which analyzes the output of the sensor 16 in conjunction with other engine parameters such as load, temperature, throttle position, rotational speed of the engine (rpm) and the like to turn the lamp 21 on and off, or which can modulate the output of the lamp. Alternatively, the controller 18 can vary the amount to. of ozone generated by the lamp 21 by varying either the voltage or current applied to the lamp 21 by the voltage converter 25 based on inputs receive from the sensor 16.

Although it is possible to continuously monitor the exhaust emissions with ozone sensors such as the Fyrite II combustion analyzer (VWR Scientific and continuously -21 WVO 97/22794 PCT/US96/20581 adjust the current flow to the ultraviolet lamp 21, it is more economical to use the further embodiments of the invention which also will be described with reference to Figure 3 wherein two or more relatively small ozone generating lamps 21a, 21b, which each convert air to ozone at a level which is less then required for full combustion by the internal combustion engine, are employed and one lamp is operated continuously and the other lamp is turned on only when the engine speed or engine load reaches a predetermined level.

In this embodiment, a controller 18 is connected to an engine sensor 16 to receive an input indicative of engine operating conditions, such as for example, temperature, throttle position, rotational speed of the engine (rpm) or engine load. When the controller 18 senses an engine operating condition at or above a predetermined level, the controller 18 turns on lamp 13b. In addition to a two lamp configuration, a plurality of lamps can be used such that one lamp is operated when necessary and each additional lamp is turned on in succession as different and increasing levels of rotation of the engine or engine load are sensed by the controller 18 so that all the lamps are operating when engine conditions, such as the engine speed or engine load, are at the highest predetermined level and sufficient ozone is generated to assure good combustion so that no excess hydrocarbons or carbon monoxide is generated.

Alternatively, a single lamp 21 can be employed and the S controller 18 can vary the amount of ozone generated by the lamp 21, for example, by varying either the voltage or current applied to the lamp 21 by the voltage converter based on inputs receive from the controller 18. It is possible to also mount the lamp 21 downstream from the engine's carburetor or fuel injection system 31 and prior to the combustion chamber, for example, in the intake manifold 45 as best seen in Figure 4.

According to a different embodiment of the invention, ozone is introduced into the precombustion or postcombustion 22 WO 97/22794 PCT/US96/20581 gas stream and thereafter the postcombustion gas stream is treated by the catalytic converter and substantial reduction in the concentration of pollutants such as CO, HC and NO., beyond which the catalytic converter alone would not attain, are obtained. According to this embodiment the lamp 21 as described above may be installed as described and the exhaust gases in the postcombustion gas stream are treated by the catalytic converter resulting in drastically reduced emissions which are below that which was attainable without the catalytic converter. The lamp 21 maybe mounted downstream from the engine's combustion chamber, for example, in the exhaust manifold 15 as best seen in Figure 4. In addition, the lamp 21 can be mounted both upstream and downstream of the combustion chamber.

Referring to Figure 5, a further embodiment of the present invention is illustrated wherein the device for generating ozone is positioned remotely of the precombustion and postcombustion gas streams and ozone enriched air is piped into the combustion gas stream. In this embodiment, an auxiliary ozone generator 50 for generating ozone from air, draws in ambient air independently of the operation of the engine, for example, using a pumping mechanism 55. The ambient air is converted to ozone enriched air by exposure, for example, to UV light, for example the UV lamp described in Figure 2, or by means of an electrostatic discharge device, and added to at least one of the precombustion or the postcombustion gas streams to reduce at least one pollutant treated by the catalytic converter. A mixing device 41 can be used to enhance mixing of the ozone enriched air with the combustion gas stream. It should be noted that in lieu of pumping mechanism 55, ambient air can be drawn in using the vacuum generated by the engine Further tests have been conducted with a 1996 Ford Taurus 3.0 L engine using the embodiment of Figure 3 where the ultraviolet lamp 13 is positioned in the intake manifold during which NO,, HC, CO, and CO, levels were measured upstream as well as downstream of the catalytic converter.

23 \O 97/22794 PCT/US96/20581 It should be noted that this type of engine has two identical catalytic converters, one connected to the right exhaust manifold and the other connected to the left exhaust manifold. The results of these tests are as forth below.

WITH DEVICE OFF

BASELINE

IDLE

CONDITIONS LEFT LEFT RIGHT RIGHT EMISSIONS PPM/PERCENT CAT-IN CAT-OUT CAT-IN CAT-OUT NO, PPM 131 2.5 116 1.2 HC PPM 2593 278 2484 137 CO PPM 5000 400 5000

CO

2 13.72 14.26 13.8 14.6 WITH DEVICE ON

IDLE

CONDITIONS LEFT LEFT RIGHT RIGHT EMISSIONS PPM/PERCENT CAT-IN CAT-OUT CAT-IN CAT-OUT

NO

x PPM 127 0.2 117 1.1 HC PPM 3048 2 2731 2 CO PPM 5000 0 5000 0

CO

2 13.87 13.9 13.99 14.27 It should be noted that the embodiments discussed above are illustrative examples. In this regard, while the use of iiiii radiant energy to produce ozone is described above, the embodiment where the exhaust gases are treated by the catalytic converter is not so limited and other devices, well known in the art, which produce ozone are envisioned as sources for adding ozone to the combustion gas stream in oeo" accordance with the teachings of that embodiment.

In addition, it should be noted that the only requirement of this embodiment is that the ozone is added to the combustion gas stream at least one point upstream of or at the catalytic converter, for example, the air intake duct to the carburetor or fuel injection systems of the combustion chamber, the air/fuel intake manifold to the combustion chamber, the combustion chamber directly or the exhaust manifold of the combustion chamber, or the exhaust pipe A as shown in Figure 1.

24- WVO 97/22794 PCT/US96/20581 Referring to Figure 6, the method of one embodiment of the invention is illustrated and comprises the steps of: 1) adding ozone to the combustion gas stream at least one point upstream from a catalytic converter for treating exhaust gases produced from the combustion of a fuel to at least reduce one pollutant from incomplete combustion and/or oxides of nitrogen, and 2) treating the exhaust gases with the catalytic converter.

In yet a different embodiment of the invention, hydroxyl is added to at least one of the precombustion and postcombustion gas streams and the exhaust (postcombustion) gas stream is then treated in a large surface area receptacle such as for example a typical automotive catalytic converter.

An apparatus of this embodiment of the invention is illustrated in Figure 7 generally at 60. In this embodiment, device 60 is a generator for generating hydroxyl and has an ultraviolet emitting lamp 21, for example, a mercury vapor arc lamp emitting ultraviolet light at a wavelength of about 185 and about 254 nanometers. The lamp has a light-transmitting envelope for transmitting UV light having wavelengths of about 100-300 nm, because this emission, in the presence of sufficient water vapor content, is capable of producing hydroxyl from air. The light transmitting envelope may be fused silica, or its equivalent synthetic quartz, supersil or any other material capable of transmitting ultraviolet light having a wavelength down to 100 nanometers, and preferably to at least 185 nanometers. Other ultraviolet generating lamps Ssuch as those containing Neon, Argon and combinations of those and other gases, for example mercury, may be used.

The lamp 21 is excited by a power supply 23 capable of providing an initial electric breakdown of the gas within the lamp and further providing a sustaining voltage for the lamp radiant output. The power supply 23 is directly connected to the electrical system 30 of the automobile by splicing into the hot wire (not shown) of the system, for example, as original equipment on a new vehicle. Alternatively, power supply 23 is connected to the electrical system 30 by using a 25 WO 97/22794 PCTIUS96/20581 plug adapted to be inserted into a cigarette lighter receptacle in the passenger compartment of the vehicle as described when referring to Figure 2.

It is important in the embodiment for effective generation of hydroxyl that sufficient water vapor, and preferably about 100% saturated air, be present in the hydroxyl generator 60 utilizing the UV lamp 21 as the means to generate the hydroxyl. This water vapor may be delivered to the generator 60 via water vapor inlet passage 65. Water vapor may be supplied to water inlet passageway 65 by any number of alternative or combination of methods including supplying water vapor to inlet passage 65 by heating water supplied from a stored bottle of water as described and illustrated with reference to Figure 8. Alternatively, water vapor may be separated from the exhaust gas stream A as illustrated in Figure 8 at an exhaust gas separator 67 and either directly supplied to inlet passage 65 without being collected in a water storage container, or alternatively through a storage container. Alternatively, the water vapor from the exhaust gas stream can be condensed and stored in a container and thereafter heated to form water vapor. In yet an additional alternative embodiment, the exhaust gas stream may be directly supplied to the hydroxyl generator. As an additional alternative embodiment, the air introduced into 25 the hydroxyl generator can be bubbled through water as described and illustrated with reference to Figure 8. This water can be supplied from an external source or may be 0-0. condensed from the water vapor present in the exhaust gas stream.

30 It is contemplated that air of sufficiently high water 0 vapor content, and preferably about 100% saturated, passing through the generator 60 as provided by the embodiment of Figure 7 will result in direct photodissociation of the water into OH and H by the adsorption of approximately 100-185 nm photons. Alternatively, the 100-185 nm UV radiation from lamp 21 acts on the air to produce ozone and atomic oxygen.

The 253.7 nm UV radiation breaks down the ozone by -26- \WO 97/22794 PCT/US96/20581 photodissociation into molecular oxygen and a metastable oxygen atom. The metastable oxygen combines with the water molecules present to form hydrogen peroxide which photodissociates in the presence of the 253.7 nm UV radiation into two hydroxyl molecules.

In the apparatus 60 as illustrated by Figure 7, the lamp 21 is positioned upstream from the engine's carburetor or fuel injection system, generally indicated at 31 in Figure 1, for example,. between an air filter 27 and air intake duct 29.

However, the present invention additionally contemplates positioning the generator 60 anywhere along the precombustion gas stream.

In order to increase the effective absorption coefficient of the oxygen in the air being inducted into the engine 10, the walls adjacent to the lamp 21 are provided with a surface highly reflective to ultraviolet light in the required wavelength range, for example, made of aluminum, in order to increase the mean free path of the ultraviolet light, since aluminum maintains its reflectance to ultraviolet light down to at least 185 nm.

According to the teaching of the present invention, it is possible to also place the hydroxyl generator S downstream from the engine's carburetor or fuel injection system 31 and prior to the combustion chamber, for example, in the intake manifold 45 as best seen in Figure 4.

Referring to Figure 10, a further embodiment of the invention is illustrated wherein the generator 60 is positioned remotely from the precombustion and postcombustion gas streams, and hydroxyl-enriched air, with other free radical intermediaries and oxidizers, is piped into the combustion gas stream. In this embodiment, hydroxyl generator 60 for generating hydroxyl from air, draws in ambient air independently of the operation of the engine, for example, using a pumping mechanism 55. The ambient air is 35 mixed with water vapor in the generator 60 or water vapor is added to the ambient air before entering the generator and the high water vapor content, preferably 100% saturated, air 27 \VO 97/22794 PCTIUS96/20581~ is converted to hydroxyl-enriched air by exposure, for example, to UV light or by means of a corona or glow discharge device, and added to at least one of the precombustion or postcombustion gas streams in accordance with the teachings of the invention.

Water vapor container 57 delivers water vapor to generator 60 to insure that the ambient air has sufficient water vapor content and preferably 100% saturated. The water vapor container 57 may be a storage bottle which contains water in any physical form, as a solid, liquid, gas or as water vapor. The water can be collected from the exhaust gases of the engine which produces water vapor as a result of combustion or it can be stored from an external source. If water vapor container 57 is liquid water, it can be converted to water vapor using any of the well-known methods such as heating in the presence of a gas such as air, or air can be bubbled through the water to achieve the water vapor input.

The water vapor and air supplied to the generator 60 can be a single input into the generator wherein water or water vapor is added to the air input supplied to the generator, this embodiment being illustrated by dashed line 51 in Figure 8.

It should be noted that water container 50 is not necessary and that water vapor can be separated from the exhaust gas stream in a water vapor separator 67 and added directly to the generator or the air inlet. Alternatively, exhaust gas *may be added directly to either the generator or the air and/or gas supplied to the generator.

S"A mixing device 41 can be used to enhance mixing of the hydroxyl-enriched air with the combustion gas stream. It should be noted that in lieu of pumping mechanism 55, ambient air can be drawn in using the vacuum generated by the engine Where the hydroxyl enriched air is introduced into the exhaust gas stream, a venturi 58 may be necessary.

Figure 9 illustrates a hydroxyl generator 60 which may be utilized in the system shown in Figure 8. Hydroxyl generator 60' has a mercury vapor lamp 21 which is connected to a power supply 61. The mercury vapor lamp 21 transmits -28- WO 97/22794 PCT/US96/20581 ultraviolet light having a wavelength of about 100-300 nm because this emission in the presence of sufficient water vapor content is capable of producing the needed amount of hydroxyl from air.

Air inlet canister 62 has a screen and an air filter (not shown) and supplies air to hydroxyl generator 60'. Air inlet passageway or pipe 64 delivers the air from the inlet canister 62 to the generator 60'. Air inlet passageway 64 may contain a pump (not shown) to facilitate the delivery of air to hydroxyl generator 60'. It is important for effective generation of hydroxyl that sufficient water vapor, and preferably 100% saturated air, be present in the hydroxyl generator utilizing the UV lamp 21 as the means to generate the hydroxyl. This water vapor may be delivered to the generator 60' via water vapor inlet passage 65'. Water vapor inlet passage 65' can collect the water vapor from the exhaust gas stream via passageway E utilizing water separator 67 as shown in Figure 8, or any of the alternative methods described herein. In Figure 8, the water vapor is supplied by heated water source 68. Heated water source 68 is an external supply of water which is circulated through the t engine via circulation pipes 69 in order to heat the water supply. The water is preferably heated to or maintained at a *0 temperature that is equal to or less than the temperature 0 25 within the hydroxyl generator. Water vapor is drawn from heated water source 68 and delivered via water vapor inlet passage 65' into the hydroxyl generator S"Alternatively, water vapor inlet 65 can connect to air inlet passageway 64 and both the air and water vapor can be mixed and then delivered to the hydroxyl generator S" Water vapor can be collected from the exhaust gas stream or the heated water source system 68, 69 can be used to supply the water vapor to water vapor inlet 65 or any of the alternative methods described herein can be utilized.

A further alternative embodiment for delivering sufficient water vapor to the hydroxyl generator 20' also is shown in Figure 9. In this embodiment, water is delivered to 29 WO 97/22794 PCT/US96/20581 and collected in a storage container 63 via water inlet Air from air inlet canister 62 is bubbled through the water to achieve sufficient water content or humidity. The water collected in storage container 63 can be from an external source, or water vapor or water from the exhaust gas stream can be condensed.

The inside surface of the hydroxyl generator 20' is provided with a surface highly reflective to ultraviolet light in the required range such.as aluminum which maintains its reflectance to ultraviolet light down to at least 185 nm.

It is believed that air of sufficient water vapor content, as supplied by the embodiment of Figure 9, passing through the generator 60 will result in direct photodissociation of the water into OH and H by the adsorption of 185 nm photons. Alternatively, the 185 nm UV radiation from lamp 21 acts on the air to produce ozone and atomic oxygen. The 253.7 nm UV radiation breaks down the ozone by photodissociation into molecular oxygen and a metastable oxygen atom. The metastable oxygen combines with the water molecules present to form hydrogen peroxide which photodissociates in the presence of the 253.7 nm UV radiation into two hydroxyl molecules.

The hydroxyl, as well as any of the free radicals and oxidizers H, O, HO 2

H

2 Oz, generated by the hydroxyl generator 60' is delivered via the generator outlet 70 to the 0 combustion gas stream. The generator output may be added to the precombustion or postcombustion gas streams. If the generator output is delivered to the postcombustion gas stream, it is anticipated that less hydroxyl output would be S 30 required for the same level of performance than if it was added to the precombustion gas stream because much of the hydroxyl, and the other free radicals and oxidizers, added to the precombustion gas stream would not survive the combustion process. The hydroxyl which survives combustion or which is delivered to the postcombustion gas stream acts upon the CO and HC in the exhaust stream to produce non-polluting CO, and

H

2 0.

30 WO 97/22794 PCTIUS96/20581 A further hydroxyl generator 60" is shown in Figure Air having sufficient water vapor is delivered to corona or glow discharge generator 60" and may be accomplished in the same manner and according to the same alternative or combination of embodiments described herein and especially when referring to Figures 7, 8 and 9. Generator 60" has an outer electrode 81 with an inner electrode 83. A dielectric material or coating 82 is inserted between outer electrode 81 and inner electrode 83. One lead from a high voltage, high frequency power supply is connected to the inner electrode 83 while the other lead is connected to the outer electrode 81.

The hydroxyl and other products of the glow discharge generator 60" are delivered via.outlet 70 to the combustion gas stream.

Figure 11 illustrates a different embodiment of a hydroxyl generator Hydroxyl generator contains an ozone generator 90 for ozone generation and an ultraviolet container 95 for ozone dissociation and hydroxyl creation.

The ozone generator 90 has an electrolytic cell 91 which receives water via water inlet 92. Water for the electrolytic cell 91 can be supplied from an external source which is stored or it may be condensed and collected from the water vapor in the exhaust gas stream produced from combustion. The electrolytic cell 91 is connected to an S 25 overvoltage power supply 93. An overvoltage electrolytic cell operates at a few tenths of a volt above the voltage condition required for the voltage threshold required for electrolysis. The electrolytic cell 91 generates ozone, oxygen and water vapor which is retained by container 94.

Container 94 has an ozone, oxygen and water vapor outlet 96 which provides a passage to the ultraviolet container Ultraviolet container 95 has an ultraviolet lamp 21' which produces 253.7 nm radiation in order to dissociate the ozone into hydroxyl pursuant to the sequence of reactions described earlier in connection with Figure 8. The ultraviolet lamp 21' is connected to a power supply Unlike the ultraviolet lamp 21 in Figure 9, lamp 21' only -31 WO 97/22794 PCT/US96/20581 needs to generate UV radiation having a wavelength of above 200 nm and preferably approximately 254 nm. The inside surface of ultraviolet container 95 is provided with a surface which is highly reflective of UV radiation having a wavelength of above 200 nm and preferably approximately 254 nm.

In a further alternative, lamp 21 (generator 20) can be mounted downstream from the engine's combustion chamber, for example, in the exhaust manifold,15 as best seen in Figure 4.

By irradiating the exhaust stream with UV radiation in the 100 to 200 nm wavelength range, in the presence of sufficient water vapor, hydroxyl will be produced by direct photodissociation.

In addition, hydroxyl generators 20, 20', 20'' and can inject hydroxyl both upstream and downstream of the combustion chamber.

It should be noted that the embodiments discussed above are illustrative examples. In this regard, while the use of radiant energy to produce hydroxyl is described above, the present invention is not so limited and other devices wellknown.in the art which produce hydroxyl are envisioned as Ssources for adding hydroxyl to the combustion. gas stream in accordance with the teachings of the present invention.

In addition, it should be noted that the only requirement of the present invention is that the hydroxyl is added to the combustion gas stream at a point upstream of or at the catalytic converter, for example, the air intake duct "to the carburetor or fuel-injection systems of the combustion chamber, the air/fuel intake manifold to the combustion chamber, the combustion chamber directly or the exhaust manifold of the combustion chamber, or the exhaust pipe 12 as shown in Figure 1.

Moreover, while the present invention has been described with reference to a catalytic converter, it is contemplated that only the high surface area provided by the converter in conjunction with the introduction of hydroxyl would be 32 WO 97/22794 PCT/US96/20581 required to reduce the pollutants in the exhaust gases of a combustion engine.

A control arrangement can be employed according to a further embodiment of the present invention as shown in Figure 12, wherein an engine sensor 16 is installed in the system. The sensor is connected to a controller 18 which can be an electronic system which is controlled by the output of engine sensor 16 or as complex as an engine control computer which analyzes the output of the sensor 16 in conjunction with other engine parameters such as load, temperature, throttle position, rpm and the like, and which can modulate the output of the hydroxyl generator 60. Alternatively, the controller 18 can vary the amount of hydroxyl generated by the hydroxyl generator 60 by varying either the voltage or current applied to the hydroxyl generator 60 by the voltage converter 25 based on inputs received from the engine sensor 16.

In an alternative embodiment a single hydroxyl generator may contain more than one ultraviolet lamp 21a, 21b, 21c, which each convert air conditioned to contain sufficient water vapor to hydroxyl at a level that is less than required for complete elimination of pollutants produced by combustion oooao of a fuel. One lamp 21a is operated when determined *°oo p eev necessary, such as when the engine is operating and the other 25 lamp 21b is modulated depending upon operating parameters as ooooo.

measured by the engine sensor 39.

In this embodiment, a controller 18 is connected to an ooooo engine sensor 16 to receive an input indicative of the .VIP current engine operating parameters or conditions. When the controller 18 senses an engine condition or parameter, such as temperature, engine speed or engine load, at or above a predetermined level, the controller 18 modulates lamp 21b and the output of the hydroxyl generator. In addition to a two generator or two lamp configuration, a plurality of generators or lamps can be used such that one generator or lamp is continuously operated when the engine is operating and each additional generator or lamp is turned on in -33- WVO 97/22794 PCT/US96/20581 succession as different and increasing levels of engine operating conditions or parameters, such as rotation of the engine or engine load, are sensed by the controller 18 so that all the generators or lamps are operating when the engine parameter or condition, such as speed or engine load, is at the highest predetermined level and sufficient hydroxyl is generated to assure no excess pollutants are generated.

In a similar arrangement, instead of a plurality of lamps 21, a plurality of sets of inner electrodes 83 and outer electrodes 81, or a plurality of ozone generators and ultraviolet light containers 95, or a plurality of lamps 21' can be utilized.

Alternatively, a single lamp 21 can be employed and the controller 18 can vary the amount of hydroxyl generated by the lamp 21 by varying either the voltage or current applied to the lamp 21 by the voltage converter 25 based on inputs received from the controller 18.

Referring to Figure 13, the method of the present invention is illustrated and comprises the steps of: 1) adding hydroxyl to the combustion gas stream at a point upstream from a high surface area receptacle, and 2) passing @0 the exhaust gases through a high surface area receptacle such as, for example, a typical automotive catalytic converter.

Although the different embodiments of the invention have been described with particular-reference to its preferred embodiments, it should be understood that many variations and modifications will now be obvious to those skilled in that ooo•• S. art, and, therefore, the scope of the invention should not be Ses limited by the specific disclosure herein, but only by the appended claims.

e 3

S..

*505 34

Claims (74)

1. An apparatus for decreasing at least one pollutant selected from the group consisting of products of incomplete combustion of fuel and oxides of nitrogen from a first concentration to a second lower concentration from the combustion of fuel in an internal combustion engine, the apparatus comprising: a combustion chamber having a pre-combustion gas stream to the combustion chamber and a post-combustion gas stream of exhaust gases from the combustion chamber; at least one generator which produces hydroxyl radicals, at least a portion of which is located in at least one of the pre-combustion gas stream and the post-combustion gas stream; a power supply which supplies high frequency power to the generator; and catalytically active material, wherein at least a portion of the catalytically active material is located downstream from the generator.

2. The apparatus according to claim 1, wherein the generator includes an ultraviolet lamp having a wavelength S between 100 and 200 nanometers.

3. The apparatus according to claim 1, wherein the S generator includes an electric discharge device.

4. The apparatus according to any one of claims 1-3, wherein the generator is located in the post-combustion gas stream such that a substantial amount of the catalytically active material is located downstream from the generator. NY2- 1139856.1 The apparatus according to any one of claims 1-4, wherein the power supply provides low power.

6. The apparatus according to claim 5, wherein the power supply uses up to approximately 40 watts of power.

7. The apparatus according to any one of the preceding claims wherein the generator is continuously provided with high frequency power substantially whenever exhaust gases are produced.

8. The apparatus according to any one of the preceding claimsused in the treatment of exhaust gas produced by the engine of a mobile vehicle.

9. The apparatus according to any one of claims 1-8 used in the treatment of exhaust gases formed from the combustion of gasoline in a spark-ignition internal combustion o engine. The apparatus according to any one of claims 1-9 used in the treatment of exhaust gases formed from the combustion of fuel at or substantially near stoichiometric conditions.

11. The apparatus according to any one of claims 1-10, wherein the catalytically active material comprises noble metals.

12. The apparatus according to any one of the preceding claims wherein the catalytically active material is contained in a catalytic converter. NY2 -1139856.1

13. The apparatus according to claim 12, wherein the catalytic converter comprises substantially non-zeolites.

14. The apparatus according to any one of claims 12 or 13, wherein the catalytic converter is a three-way catalytic converter. The apparatus according to any of claims 1-8 and 11- 14 used in the treatment of exhaust gases formed from the combustion of gas under oxygen-rich conditions.

16. The apparatus according to claim 15 used in the treatment of exhaust gases formed from the combustion of diesel fuel in an internal combustion engine.

17. The apparatus according to any one of the preceding claims designed and configured so that no reducing agents are added downstream from the combustion chamber. O "0'0.20 18. The apparatus according to any one of the preceding 0oo4o: 0 claims wherein the catalytically active material comprises a monolithic structure. ooeoo

19. The apparatus according to any one of the preceding claims wherein the decrease in the pollutants selected from .00. 00.0 the groups consisting of products of incomplete combustion of fuel and oxides of nitrogen occurs substantially within the catalytic converter.

20. The apparatus according to any one of the preceding claims wherein the power supply provides current at a frequency of at least about 1000 Hz. NY2- 1139856.1 38

21. The apparatus according to any one of claims 1-20 wherein the power supplied to the discharge device is approximately 0.01% to approximately 0.1% of the ratio engine power.

22. The apparatus according to any one of claims 1-21 used to decrease carbon monoxide, unburnt hydrocarbons, particulates and oxides of nitrogen.

23. A device for improving the performance of a catalytic converter to decrease at least one pollutant selected from the group consisting of products of incomplete combustion of fuel and oxides of nitrogen from a first concentration to a second lower concentration in an exhaust gas containing exhaust gases formed from the combustion of fuel in an internal combustion engine of a mobile vehicle, comprising: an exhaust passageway for channeling at least a portion of the exhaust gases from the engine; at least one electric discharge device at least a eeooee portion of which is located in the exhaust passageway; a power supply which provides high frequency power to at least one electric discharge device; and a catalytic converter having catalytically active material positioned in the exhaust passageway, wherein at eeoc least a portion of the catalytically active material is located downstream from the at least one electric discharge device.

24. The device according to claim 23 used in the treatment of exhaust gases produced by a spark-ignition internal combustion engine. NY2 1139856.1 The device according to any one of claims 23 or 24 used to treat the exhaust gases produced by an internal combustion engine which burns fuel at or substantially near stoichiometric conditions.

26. The device according to any one of claims 23-25, wherein the catalytic converter comprises noble metals selected from the group consisting of platinum palladium (Pd) and rhodium (Rh).

27. The device according to any one of the claims 23-26, wherein the catalytic converter comprises at least one monolithic substrate.

28. The device according to any one of claims 23-27 wherein a pre-determined distance of exhaust passageway separates at least one electric discharge device and the catalytically active material of the catalytic converter.

29. The device according to any one of claims 23-28, S wherein the catalytic converter comprises a ceramic-type catalyst. The device according to any one of claims 23-29, wherein the catalyst is not primarily a zeolite catalyst.

31. The device according to any one of claims 23-30, wherein the power supply provides current at a frequency of at least about 1000 Hz.

32. The device according to any one of claims 23-31, wherein the power supply utilizes low power. NY2 1139856.1

33. The device according to claim 32, wherein the power supply uses up to approximately 40 watts of power.

34. The device according to any one of claims 23-33, wherein the power supply supplies about 1 Kilovolt to about Kilovolts to the electric discharge device. The device according to any one of claims 23-34 wherein the catalytic converter comprises a three-way catalytic converter.

36. The device according to any one of claims 23-24 or 26-33 applied to the treatment of exhaust gases produced by an internal combustion engine which burns fuel under oxygen-rich conditions.

37. The device according to claim 36 applied to the treatment of exhaust gases produced by the combustion of diesel fuel in an internal combustion engine. .2 0

38. The device according to any one of claims 23-37, wherein the catalytic converter comprises zeolites.

39. The device according to any one of claims 23-38 5 wherein the at least one electric discharge device is continuously powered whenever exhaust gases are produced by the engine. The device of claims 23-39 designed and configured such that no reducing agents are added downstream from the combustion chamber. NY2- 1139856.1 41

41. The device according to any one of claims 23-40, wherein the electric discharge device, comprises: at least one first electrode; at least one second electrode; and at least one dielectric barrier positioned between the first electrode and the second electrode.

42. The device according to any one of claims 23-41 wherein the power supplied to the discharge device is approximately 0.01% to approximately 0.1% of the rated engine power.

43. The device according to any one of claims 23-42 used to decrease carbon monoxide, unburnt hydrocarbons, particulates and oxides of nitrogen.

44. A method for decreasing at least one pollutant selected from the group consisting of products of incomplete combustion of fuel and oxides of nitrogen from a first '20 concentration to a second lower concentration in an exhaust ooooo gas stream containing exhaust gases formed from the combustion of fuel in an engine having a pre-combustion flow stream to the engine and a post-combustion flow stream from the engine, the method comprising the steps of: positioning at least a portion of at least one generator which has the capability of producing hydroxyl radicals in at least one of the pre-combustion and post- combustion flow streams; providing high frequency current to the generator; and NY2 1139856.1 providing catalytically active material in the post combustion flow stream such that at least a portion is located downstream from the at least one generator.

45. The method according to claim 44, wherein the at least one generator is at least partially positioned in the post-combustion flow stream.

46. The method according to any one of claims 44 or wherein the generator is positioned upstream of a substantial amount of the catalytically active material.

47. The method according to any one of claims 44-46, wherein the generator works by means of radiation which converts water vapor to hydroxyl.

48. The method according to any one of claims 44-46, o wherein the generator comprises an electric discharge device.

49. The method according to any one of claims 44-48 used to treat exhaust gases from an engine of a mobile vehicle. The method according to any one of claims 44-49, wherein the power supply provide current having a frequency of at least about 1,000 Hz.

51. The method according to any one of claims 44-50, further comprising providing a power supply which supplies power to the generator, wherein the power supply utilizes low power. NY2 1139856.1 43

52. The method according claim 51, wherein the power supply provides up to about 40 watts of power.

53. The method according to any one of claims 44-52, further comprising continuously powering the electrical discharge device substantially whenever exhaust gases are produced by the engine.

54. The method according to any one of claims 44-53, wherein the catalytically active material is not primarily a zeolite. The method according to any one of claims 44-54, wherein the catalytically active material includes at least one noble metal.

56. The method according to any one of claims 44-55, o wherein the generator is located upstream of all the catalytically active material in the post-combustion flow stream. 0000**

57. The method according to any one of claims 44-56 S wherein the catalytically active material comprises monolithic structures. *2 *.25 9990

58. The method according to any one of claims 44-57 wherein no reducing agents are added to the post-combustion flow stream. 9090

59. The method according to any one of claims 44-58 used to treat exhaust gases produced by a spark ignition internal combustion engine. NY2 1139856.1 44 The method according to any one of claims 44-59 used to treat exhaust gases produced by the combustion of fuel at or substantially near stoichiometric conditions.

61. The method according to any one of claims 44-58 used to treat exhaust gases produced by the combustion of diesel fuel.

62. The method according to any one of claims 44-61 wherein at least a portion of the catalytically active material is contained in a catalytic converter.

63. The method according to any one of claims 44-62, wherein at least one generator is separate from the catalytically active material of the catalytic converter.

64. The method according to any one of claims 62 or 63 o wherein the decrease in pollutants occurs substantially within the catalytic converter. O The method according to any one of claims 44-64, wherein the electric discharge device, comprises: at least one first electrode; at least one firstecond electrode; and at least one second electrode; and 25 at least one dielectric barrier positioned between the first electrode and the second electrode.

066. A method for decreasing at least one pollutant selected from the group consisting of products of incomplete combustion of fuel and oxides of nitrogen from a first concentration to a second lower concentration in an exhaust gas stream containing exhaust gases formed from the combustion NY2- 1139856.1 of fuel in an internal combustion engine having an exhaust passageway for channeling the exhaust gas stream from the internal combustion engine, the method comprising: positioning at least a portion of at least one electric discharge device in the exhaust passageway; providing high frequency current to the at least one electrical discharge device; exposing at least a portion of the exhaust gases to the output of the at least one electric discharge device; positioning in the exhaust passageway catalytically active material at least a portion of which is not exposed directly to the output of the at least one electric discharge device; and passing at least a portion of the exposed exhaust gases through at least a portion of the catalytically active material.

67. The method according to claim 66 wherein a reducing S" agent is not added to the exhaust passageway prior to exposing the exhaust gases to the output of the electric discharge OV 0: device. .oo.o*

68. The method according to any one of claims 66 or 67 wherein a reducing agent is not added to the exhaust gases "'25 prior to passing the exposed gases through at least a portion of the catalytic active material of the catalytic converter.

69. The method according to any one of claims 66-68 wherein the step of providing electrical power includes connecting a power supply to the electric discharge device which supplies current having a frequency of at least about 1000 Hz. NY2- 1139856.1 The method according to any one of claims 66-69 wherein the electric discharge device does not contain any catalytically active material.

71. The method according to any one of claims 66-70, wherein the catalytically active material comprises monolithic substrates.

72. The method according to any one of claim 66-71 further comprising providing high frequency current to the electric discharge device substantially whenever the discharge device is exposed to exhaust gases.

73. The method according to any one of claims 66-72, wherein the catalytic converter comprises zeolites.

74. The method according to any one of claims 66-73, o wherein a power supply provides current to the electric discharge device and the power supply uses low power. The method according to claim 74, wherein the power supply uses up to approximately 40 watts of power.

76. The method according to any one of claims 66-75, wherein the catalytically active material includes noble metals selected from the group consisting of platinum (Pt), palladium (Pd) and Rhodium (Rh)

77. The method according to any one of claims 66-75 wherein the catalytically active material is contained in a catalytic converter. NY2 1139856.1

78. The method according to any one of claims 66-76 wherein the decrease in concentration of at least one pollutant occurs substantially within the catalytic converter.

79. The method according to any one of claims 66-78, wherein about one kilovolt to about 20 kilovolts is supplied to the electric discharge device. The method according to any one of claims 66-79, wherein the catalytically active material is not primarily a zeolite.

81. The method according to any one of claims 66-80, wherein the catalytic converter comprises a ceramic-type catalyst.

82. The method according to any one of claims 66-81, S wherein the catalytic converter is a three-way catalytic converter.

83. The method according to any one claims 66-82, wherein the exhaust gases are produced from the combustion of Oooe fuel in a spark-ignition engine. •'25 84. The method according to any one of claims 66-83, wherein the exhaust gases are formed by the combustion of a substantially stoichiometric mixture of fuel and air. The method according to any one of claims 66-83, wherein the exhaust gases are produced by the combustion of fuel in an internal combustion engine under oxygen-rich conditions. NY2 1139856.1

86. The method according to claim 85, wherein the exhaust gases are produced by the combustion of diesel fuel.

87. The method according to any one of claims 66-86 used to treat exhaust gases from an engine of a motor vehicle.

88. The method according to any one of claims 66-87 used to decrease carbon monoxide, unburnt hydrocarbons, particulates and oxides of nitrogen.

89. The method according to any one of claims 66-88 wherein the power supplied to the discharge device is approximately .01% to approximately of the rated engine power. The method according to any one of claims 66-89, wherein the electric discharge device, comprises: o*o. at least one first electrode; at least one second electrode; and 2 0 at least one dielectric barrier positioned between the first electrode and the second electrode. oo91. An apparatus, according to claim 1, substantially as hereinbefore described with reference to any one of the drawings.

92. A device, according to claim 23, substantially as hereinbefore described with reference to any one of the drawings.

93. A method, according to claim 44 or 66, substantially as hereinbefore described with reference to any one of the drawings. DATED: 6 February, 2000 PHILLIPS ORMONDE FITZPATRICK Attorneys for: LITEX, INC.1