CA1205980A - Method for control of aldehyde and unburned fuel emissions from alcohol-fueled vehicles - Google Patents

Method for control of aldehyde and unburned fuel emissions from alcohol-fueled vehicles

Info

Publication number
CA1205980A
CA1205980A CA000431457A CA431457A CA1205980A CA 1205980 A CA1205980 A CA 1205980A CA 000431457 A CA000431457 A CA 000431457A CA 431457 A CA431457 A CA 431457A CA 1205980 A CA1205980 A CA 1205980A
Authority
CA
Canada
Prior art keywords
alcohol
catalyst
bed
exhaust
exhaust gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000431457A
Other languages
French (fr)
Inventor
Stephen J. Harris
Robert W. Mccabe
Patricia J. Mitchell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Motors Liquidation Co
Original Assignee
Motors Liquidation Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US44289282A priority Critical
Priority to US442,892 priority
Application filed by Motors Liquidation Co filed Critical Motors Liquidation Co
Application granted granted Critical
Publication of CA1205980A publication Critical patent/CA1205980A/en
Expired legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/0807Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0828Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
    • F01N3/0835Hydrocarbons
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F01N13/0097Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are arranged in a single housing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/0807Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0814Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28Construction of catalytic reactors
    • F01N3/2803Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
    • F01N3/2832Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support granular, e.g. pellets
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28Construction of catalytic reactors
    • F01N3/2839Arrangements for mounting catalyst support in housing, e.g. with means for compensating thermal expansion or vibration
    • F01N3/2846Arrangements for mounting catalyst support in housing, e.g. with means for compensating thermal expansion or vibration specially adapted for granular supports, e.g. pellets
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28Construction of catalytic reactors
    • F01N3/2882Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/18Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being an adsorber or absorber
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2250/00Combinations of different methods of purification
    • F01N2250/12Combinations of different methods of purification absorption or adsorption, and catalytic conversion
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2370/00Selection of materials for exhaust purification
    • F01N2370/22Selection of materials for exhaust purification used in non-catalytic purification apparatus
    • F01N2370/24Zeolitic material
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2570/00Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
    • F01N2570/20Formaldehyde
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/30Arrangements for supply of additional air
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02ATECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection
    • Y02A50/20Air quality improvement or preservation
    • Y02A50/23Emission reduction or control
    • Y02A50/232Catalytic converters
    • Y02A50/2322Catalytic converters for exhaust after-treatment of internal combustion engines in vehicles

Abstract

C-3,447 D-6,669 METHOD FOR CONTROL OF ALDEHYDE
AND UNBURNED FUEL EMISSIONS
FROM ALCOHOL-FUELED VEHICLES

Abstract of the Disclosure A method for treating exhaust of an alcohol-fueled engine is disclosed in which the exhaust, at least following cold start and during engine warm-up, is passed through a dual bed converter consisting of a zeolite adsorbent followed by an oxidation catalyst.
The zeolite adsorbs and holds unburned fuel and alde-hydes until the catalyst is heated to its operating temperature.

Description

1213iS~

D-6,669 C-3,447 METHOD FOR CONTROL OF ALDEHYDE
: AND UNBURNED FUEL EMISSIONS
FROM ALCOHOL-FUELED VEHICLES

This invention relates to treatment of exhaust gases from an alcohol-fueled automotive internal combustion engine. More particularly, it relates to reducing alcohol and aldehyde emissions following engine cold start during warm-up.
Reciprocating internal combustion engines in automotive passenger cars and trucks have been operated using an alcohol, such as methyl alcohol or ethyl alcohol, as a fuel. It is known that ethyl alcohol may be substituted as a fuel for gasoline in present vehicle engines with suitable modifications.
~s the number o alcohol-fueled vehicles increases there may be increased attention given to the emis-sions they produce.
Ideally, the engine would be operated such that the fuel is burned as completely as possible to carbon dioxide and water without concomitant oxidation of nitrogen. Normally, however~ significant amounts of nitrogen oxides (NOx), carbon monoxide ~CO) and unburned or partially oxidized fuel constituents are exhausted from the vehicle. Typically, alcohol-fuelPd vehicles produce smaller amounts of NOX than their gasoline-fueled counterparts. However, alcohol ~ueled engines do produce significant quantities of carbon monoxide and unburned ~uel (including aldehydes), particularly during the period of vehicle operation following engine cold start and during engine warm-up.
An engine cold start is the common situation in which the vehicle is started when the engine is at ambient temperature. The air-fuel ratio is often too rich ~2~5~

for complete combustion of the fuel. Also, the initially produced exhaust gas is cooled as it passes through the engine exhaust manifold and the exhaust pipe, muffler and tail pipe of the vehicle. ~uch cooling of the exhaust may impair removal of carbon monoxide or unburned fuel. The engine must operate for a period of a few minutes before it and the exhaust system reach a more or less normal operating temperature and condition.
Exhaust gases from a vehicle engine that contain sufficient oxygen can be brought into contact with an oxidation catalyst to accelerate the oxidation of carbon monoxide and unburned fuel constituents.
With gasoline engines, oxidation catalysts have been quite effectively used for this purpose. The active catalytic material has been a small amount of, for example, a noble metal such as platinum and/or palla-dium. Base metal such as a copper-chromium mixture also has utility. The active catalyst metal is distributed in an extremely thin layer on a high surface area, temperature stable ceramic carrier, such as alumina~ The carrier may be in the form of a small pellet or of a small powdered washcoat on a ceramic honeycomb monolith. The pellets or monoliths are housed in a temperature resistant metal converter having an inlet and outlet and loca-ted in the exhaust system of the vehicle close to the exhaust manifold.
Such catalysts do not display a high effi-ciency for conversion of unburned fuel constituents until they have been heated to a threshold or light-off temperature of about 300 C. These catalytic converters are usually heated solely by interaction with the exhaust gas. Depending upon ~heir mass they may require several minutes until they are hot enough ~or efficient oxidation. Carbon monoxide and unburned 3tS9~

hydrocarbons from gasoline may pass through a cold converter substantially unchanged. The amount of the unwanted emission produced is not increased by the inefficient sonverter. However, in the case of alcohol we have found that the cold,inefficient oxidation converter may induce partial oxidation of the unburned fuel to undesirable aldehydes. In other words, in the start up and warm-up of an alcohol-fueled engine the quantity of unwanted exhaust by-products may actually be increased when an oxidation converter is e~ployed.
It is an object of this invention to provide a method of treating the flow of unburned fuel constituents from an alcohol-fueled engine during engine warm-up to reduce or minimize the discharge of unwanted constituents to the atmosphere.
It is a more specific object of this inven-tion to provide a method of using an adsorbent zeolite bed in combination with a suitable oxidation catalyst to reduce the d~scharge of exh~ust emissions from an alcohol-fueled engine, especially in the period from cold start through engine warm-up~ Advantageously, our method may be practiced using a passive system, i~e., it does not require superfluous valves, controls or other means to divert or direct the flow of exhaust gases.
It is a still further ob]ect of the present invention to provide a method o~ decreasing such exhaust emissions by using an adsorbent bed which will naturally adsorb unburnsd alcohol and aldehydes when the exhaust stream is relatively cool and prevent the alcohol and aldehydes from rPaching a cold, in-efficient oxidation catalyst. Later when the catalyst is hot, the adsorbent bed will release the alcohol and aldehydes to the converter where they are efficiently oxidized to innocuous by-products.

lZ~5~8~D

Bxief Summary of the Invention In accordance with a preferred embodiment of our invention, these and other objects and advan-tages are accomplished by placing a dual bed converter, containing both a zeolite molecular sieve adsorbent and an oxidation catalyst, in the exhaust system of the alcohol-fueled vehicle. The zeolite bed comprises particles ~f a suitable aluminosiliate composition having a crystal ~tructure in the form of a three-dimensional cage-like network. The bed can adsorb or trap alcohol and aldehyde molecules from a hot ~up to 250 C. to 300 C.) exhaust gas stream. The oxidation catalyst is immediately downstream of the zeolite bed. It promotes the complete oxidation of alcohol or aldehydes in the presence of oxygen when it is at a temperature of about 25G C. to 300 C.
or higher.
Following an engine cold start, exhaust gases are pumped from the combustion cylinder~ by the reciprocating pistons. ~he gas flows sequen-tially through the exhaust manifold, an exhaust pipe, the zeolite bed, the oxidation catalyst, and finally out the tail pipe to the atmosphere~ At first, these exhaust gases are relatively cool and fuel-rich be~ause the engine and the exhaust system have not been heated to their normal operating state. When the relatively cool gases flow through the zeolite bed, unburned alcohol and any aldehyde by-products are adsorbed in the bed. These constituents do not ~each the then ineffective oxidation catalyst. The major portion of the exhaust stream comprising nitro-gen, carbon monoxide, carbon dioxide and the like, flows through the oxidation converter and out the tail pipe. They commence heating of the converter as they flow.

~s~

The temperature of the exhaust gas stream reaching the adsorbent bed and catalyst continuss to increase during the first couple of minutes of engine operation, but alcohol and aldehyde constituents are trapped and held in the zeolite bed. ~s the exhaust gas heats or interacts with the catalyst to heat it to a temperature approaching, for example 300 C., the zeolite bed is also warmed and begins to give up or release the alcohol and aldehydes. At this point the catalytic convexter is capable of efficiently promoting the oxidation of these materials fully to carbon dioxide and water. The discharge of aldehyde or other partially oxidized alcohol by-products to the atmosphere is reduced or minimized.
Further operation of the engine and exhaust system at normal operating temperature, purges or regenerates the zeolite bed of adsorbed exhaust emissions. This soon restores its capacity to repeat its storage function following a subsequent cold start. The catalytic converter continues to perform its oxidation function. The zeolite is thermally stable at normal exhaust temperatures and the adsorb-ent bed need not be by-passed during normal engine operation.
Thus, by using a zeolite adsorbent bed in an exhaust system containing an oxidation converter, the system will naturally hold back unburned alcohol during engine start-up and release it at normal engine operation. In a particularly convenient embodiment a known dual bed downflow catalytic convPrter struc-ture can be employed in which zeolite particles constitute the upper bed and oxidation catalyst pellets make up the lower bed.
In one embodiment of our invention i~ may also be useful to add a suitable quantity of secondary air to the exhaust stream, upstream of the zeoLi~e 12~59B~

bed. This practice and its advantages will be des-cribed in more detail below.
Our method will be better understood in view of a detailed description thereof in which reference will be made to the drawing in which the single Figure of the drawing is a schematic flow diagram depicting our method.
Detailed Description of the Invention We have tested and demonstrated the practice of our method on an e~hanol-~ueled Bra~ilian made automobile (by GM do Brasil), an Opala Commodoro~
The vehicle was equipped with a 2.5 L displacement engine, a four-speed manual transmission and manual choke. The vehicle was used to perform emission tests and was then operated on a chassis dynamometer. The car was operated following the eighteen specific cycles prescribed by the 1978 United States Federal Test Procedure (FTP). Provision was made to operate the manual choke and manual transmission during the eighteen cycles of the procedure. The first ive cycle~ were in the cold start phase and thirteen cycles were in the stabilized phase.
~ 250 cubic inch total capacity dual bed downflow catalytic converter was installed in the vehicle's exhaust system just under the floor of the front passenger compartment. The exhaust stream flow path was like that shown in the Figure of the drawing.
All of the exhaust gases emanating from th~ engine flowed through the converter and then out the tail pipe to the atmosphere. Provision was made for sampling exhaust gases at the exhaust manifold and the end of the tail pipe. However, no provision was made to inject secondary air and no other modifica-tions were made in this exhaust sys~em. The ~op half (125 cubic inches) of the dual bed was filled with Union Carbide Corporation's Linde 13X*type zeolite - molecular sieve pellets. The lower half of the dual bed converter was filled with oxidation catalyst pellets. We have conducted tests using 3 mm diameter alumina beads impregnated with platinum and palladium (Pt-Pd catalyst). We have also conducted tests with hopcalite catalyst particles. The Pt Pd catalyst was a commer-cial oxidi~ing catalyst for exhaust emissions. It contained 0.054 weight percent Pt and 0.022 weight percent Pd. The hopcalite catalyst was a mixture of coppex and manganese oxides obtained from Mine Safety Appliances Company.
The converter size and location was similar to those used on comparable United States gasoline-fueled vehicles but no attempt was made to determinewhether the size or location was optimal.
For purposes of comparison, like tests were also conducted with the same car using a single bed catalytic converter containing no zeolite adsorbent but filled with 160 cubic inches of oxidation catalyst.
While these tests were intended to provide a comparison of the effect of the oxidizing converter on engine operation without the use of the adsorbent bed, it is to be noted that the amount of ox.idi~ing catalyst was greater in this instance.
The fuel was a blend of 6 volume percent (7.6 weight percent) water in ab olute (undenatured) ethyl alcohol. This mixture was selected to approxi-mate the composition of a normally pure ethanol fuel.
The following observations were made from analysis of the engine-out emissions and the tail pipe emissions by operatiny the alcohol~fueled vehicle in three different modes~ ll) without modification (i.e., no catalytic converter or adsorbent bed);

(2) with only a catalytic converter in the exhaust *trademarK 7 ~. .. ~

~z~

system; and (3) with the dual bed zeolite adsorbent-oxidation catalyst. In our evaluation o our method we focussed on aldehyde emissions.
As would be expected, the use of an oxidation catalyst ~lone (as compared to no emission control at all) is not effective in reducing aldehyde emissions immediately following cold start or for much of the engine warm-up period.
In fact, some oxidation catalysts, such as a copper-chromium oxidation catalyst, will actually substan-tially increase aldehyde emissions during this period.
This is apparently because th~ catalyst is effective in initiating some oxidation, converting the ethanol to acetaldehyde, but is not effective to complete the lS oxidation to carbon dioxide and waterO It was soon realizea that aldehyde emissions from an alcohol-fueled engine could not readily be controlled during engine warm-up by simply adding an oxidation catalyst.
In operating the vehicle described we found that the 160 cubic inch hopcalite catalyst bed alone reduced aldehyde emissions over the full eighteen-cycle FTP
procedure about 59~ when compared to aldehyde emis-sions from the vehicle operated without any exhaust control. Of course, this full procedure included five cycles of cold engine start and warm-up, plus thirteen cycles of stabilized operation. On the same basis, the Pt-Pd catalyst alone reduced aldehyde emissions about 70%.
Much of the aldehyde emissions that escaped the tail pipe were generated during the first five cycles of the FTP.
A significant improvement was obtained when the tests were repeated using the dual bed downflow ~2~S~8~

converter. In one instance it contained a Linde 13X
zeolite upper bed and hopcalite catalyst lowér bed and in the other instance it contained an upper bed of 13X zeolite and a lower bed of Pt-Pd. Aldehyde emissions with the zeolite and hopcalite dual bed were only 70% of those with the hopcalite alone.
Aldehyde emissions with the Pt-Pd catalyst and zeo-lite were 53% of those with the Pt-Pd catalyst alone.
During the FTP cycle runs the manual choke is partially closed through three of the five cycles during engine warm~up following cold start. This, of course, means that the engine runs rich and that the exhaust gas probably does not contain suffi~ient oxygen to complete the oxidation of unburned alcohol.
For this reason it may be desirable in some practices of our method to employ a conventional air pump to inject secondary air into the exhaust stream, just upstream of the zeolite bed. A suitable point of injection of this secondary air stream is indicated by the dotted line in the Figure of the drawing.
This air stream would serve sever~ useful purposes.
It would assure that there would be sufficient oxygen in the exhaust stream at all time~ to complete the oxidation of all unburned emission constituents reach-ing an operating oxidation catalyst. It also would reduce the temperature of the exhaust stream enteringthe zeolite bed and thus delay the time at which adsorbed alcohol is purged from the bed. At the same time, the oxygen and carbon monoxide flowing through the ~eolite bed to the oxidation catalyst would tend to raise its temperatuxe by undergoing exothermic reaction, and thus shorten the period from cold start until the catalyst is at its effective temperature.

~Z~:P5~8~:3 We have also shown the effectiveness of our method in a laboratory reactor. We formed a dual bed of Linde 13X molecular sieve and hopcalite catalyst in a tube furnace. We formed a synthetic exhaust stream ~onsisting of l,OOO ppm ethanol and 1% oxygen in nitrogen and passed it through the dual bed. At the same time, we started heating the tube furnace from ambient temperature to 350 CO We were able to heat to that temperature and maintain that te~perature without the observation of ethanol or acetaldehyde in the reactor effluent. The only carbon-containing products observed in the reactor effluent were carbon dioxide and a small amount of ethylene. Small amounts of ethylene are formed on the molecular sieve from the dehydration of ethanol.
It is the cooperation between the zeolite molecular sieve and the oxidation catalyst that is the basis of our passive exhaust treatment method.
The former works (adsorbs) while the latter is warming up. When the catalyst is operative~ the adsoxption bed is regenerating itself. Of course, the æeolite is only needed because known, effective and durable oxidation catalysts are not fully operative until they are hot. Th~ selection of a particular oxidatiGn catalyst is not a critical aspect o~ our invention.
The oxidation catalyst presently commonly used consists of platinum or mixtures of platinum and other noble metals, notably palladium. As statedl they are commonly used as coatings on alumina pellets or beads or on ceramic monolithic honeycombs. Other oxidation catalyst compositions include copper~chromium ~for example, CuO-CuCr2043 and hopcalite (a typical mixture consists of 60% MnO2 and 40~ CuO). In addition, there are a large number of other metal oxide-containing materials that are efrective to some degree as oxidation catalysts.

~s~

ll There are mineral zeolites and synthetic zeolites. In general, they are crystalline alumino-silicates high in silica. They usually contain a cation such as ~odium, potassium, ammonium, calcium, barium or the like. It is known by X-ray crystal structure analysis that many of them have framPwork, crystal structures that are sieve-like on a molecular scale. They have known utility for carrying out operations by selective adsorption of molecules.
We used a commercially available synthetic zeolite, a faujasite type framework structure -Zeolite 13X* The material was obtained from Union ; Carbide Corporation. The typical unit cell contents of Zeolite 13Y.*are Na86[(AlO~)86(SiO2)106] 2 This material is known to be capable of adsorbing molecules as large as tributylamine under suitable conditions.
We considered Zeolite 13X~suitable ~or use in our method with the engine and oxidation catalyst employed. However, we view that ùse as merely illustrative and do not intend to be limited to this particular form of zeolite. Other zeolites, including other X-type zeolites, may be preferred in other engine oxidation catalyst combinations.
Z5 As noted above, an important feature of our method is that the combination of the zeolite bed and oxidation catalyst can function passively. Aldehyde and alcohol emissions to the atmosphere can be decreased simply by directing the engine exhaust gas stream sequentially through the two beds. The beds do not have to be heated or cooled apart from their natural interaction with the exhaust stream. In the preferred mode of practicing the invention, no provision has to be made for bypassing the catalyst bed durin~ engine warm-up or for bypassing the zeolite bed when the * trademar~ 11 exhaust is hot. No special purge stream ~other than exhaust gas) need be used to remove adsorbed alcohol or aldehyde from the zeolite and thus restore or regenerate its adsorbent capacity for the next time the engine is started cold. Of course, as we have stated, it may be useful to inject air into the exhaust stream before it reaches the dual bed converter or before it reaches the catalyst bed. However, this is for the purpose of assuring there is sufficient oxygen in the exhaust stream to complete the combustion of the emissions. This practice is known. When sing it, it is for the purpose of improving the results of our method but it is not necessary to the practice of the method~
~ 15 We know of no other adsorbent material that - can be used in place of the zeolite in the practice of our method. While there are many other known adsorbent materials, none so far as we know will trap and hold aldehydes and unburned alcohols from a hot exhaust stream until an oxidation catalyst has been heated to its light-off temperature.
While our invention has been disclosed in terms of a preferred Pmbodiment thereof, it will be appreciated that other forms could readily be adapted by one skilled in the art. Accordingly, our invention is to be limited only by tne scope of the following claims.

Claims (3)

The embodiments of the invention in which an exclusive property of privilege is claimed are defined as follows:
1. The method of reducing exhaust emissions from an alcohol-fueled automotive vehicle during engine cold start and warm-up, comprising directing the initially relatively cool engine start-up exhaust gas through a bed of zeolite particles and then over an oxidation catalyst before the gas is discharged to the atmosphere, said zeolite adsorbing unburned or incompletely burned alcohol from the exhaust stream and the exhaust gas then commencing heating of the catalyst to its effective operating temperature.
continuing to pass progressively warmer exhaust gas through said bed and over said catalyst, the bed continuing to adsorb alcohol or its partially oxidized by-products and the catalyst continuing to be heated by the exhaust gases, and further continuing such passage of exhaust gas at a temperature sufficient to remove adsorbed alcohol and by-products from said bed and to carry them to the catalyst where effective oxidation is promoted.
2. The method of reducing exhaust emissions from an alcohol-fueled automotive vehicle during engine cold start and warm-up, comprising passing the exhaust gas from the time of engine start and continually thereafter through a bed of zeolite adsorbent material and then into contact with an initially unheated oxidation catalyst before the gas is discharged to the atmosphere, whereby, at first, aldehyde and unburned alcohol constituents in the exhaust gas are adsorbed on the zeolite where they are temporarily stored and prevented from raw discharge to the atmosphere, the continuing flow of zeolite-contacted exhaust gas then gradually heating the oxidation catalyst to a temperature region in which it can effectively promote the oxidation of such constitu-ents, the zeolite continuing to adsorb and store such constituents until it is heated by the exhaust to approximately the operating temperature of the cata-lyst whereupon it releases adsorbed constituents back to flowing exhaust gas in which they are carried to the catalyst and burned before discharge to the atmosphere, the removal of the constituents from the zeolite restoring its capacity to again adsorb like constituents from a cold start engine exhaust.
3. The method of reducing exhaust emissions from an alcohol-fueled automotive vehicle during engine cold start and warm-up, comprising directing the initially relatively cool engine start-up exhaust gas through a bed of zeolite particles and then over an oxidation catalyst before the gas is discharged to the atmosphere, said zeolite adsorbing unburned or incompletely burned alcohol from the exhaust stream and the exhaust gas then commencing heating of the catalyst to its effective operating temperature, continuing to pass progressively warmer exhaust gas through said bed and over said catalyst, the bed continuing to adsorb alcohol or its partially oxidized by-products and the catalyst continuing to be heated by the exhaust gases, further continuing such passage of exhaust gas at a temperature sufficient to remove adsorbed alcohol and by-products from said bed and to carry them to the catalyst, and adding air to the exhaust gas stream before it reaches the catalyst if necessary to provide sufficient oxygen in the stream for effi-cient oxidation of removed constituents to carbon dioxide and water.
CA000431457A 1982-11-19 1983-06-29 Method for control of aldehyde and unburned fuel emissions from alcohol-fueled vehicles Expired CA1205980A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US44289282A true 1982-11-19 1982-11-19
US442,892 1982-11-19

Publications (1)

Publication Number Publication Date
CA1205980A true CA1205980A (en) 1986-06-17

Family

ID=23758561

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000431457A Expired CA1205980A (en) 1982-11-19 1983-06-29 Method for control of aldehyde and unburned fuel emissions from alcohol-fueled vehicles

Country Status (2)

Country Link
BR (1) BR8306309A (en)
CA (1) CA1205980A (en)

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0424966A1 (en) * 1989-10-27 1991-05-02 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification device in variable combination of absorbent and catalyst according to gas temperature
US5051244A (en) * 1990-07-20 1991-09-24 Uop Use of a molecular sieve bed to minimize emissions during cold start of internal combustion engines
US5078979A (en) * 1990-07-20 1992-01-07 Uop Molecular sieve bed/catalyst to treat automotive exhaust
US5125231A (en) * 1990-06-08 1992-06-30 Corning Incorporated Dual converter engine exhaust system for reducing hydrocarbon emissions
US5142864A (en) * 1991-09-30 1992-09-01 Uop Process for treating an engine exhaust stream employing a catalyst, an adsorbent bed and a turbocharger
US5207734A (en) * 1991-07-22 1993-05-04 Corning Incorporated Engine exhaust system for reduction of hydrocarbon emissions
US5269140A (en) * 1989-10-24 1993-12-14 Nichias Corporation Exhaust gas purifier for methanol-fueled engines
US5271914A (en) * 1990-04-04 1993-12-21 Tosoh Corporation Process for adsorbing the vapor of alcoholic fuels
US5303547A (en) * 1992-04-15 1994-04-19 Amoco Corporation Emissions control system and method
US5331809A (en) * 1989-12-06 1994-07-26 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification system for an internal combustion engine
US5365734A (en) * 1992-03-25 1994-11-22 Toyota Jidosha Kabushiki Kaisha NOx purification apparatus for an internal combustion engine
US5379586A (en) * 1991-09-20 1995-01-10 Hitachi, Ltd. System for controlling oxygen concentration in exhaust gas and exhaust gas cleaning system employing the same
US5531068A (en) * 1995-06-19 1996-07-02 Uop Combination catalyst/adsorber system for treating an engine exhaust gas stream
US5577383A (en) * 1991-09-20 1996-11-26 Hitachi, Ltd. Apparatus for controlling internal combustion engine
US6089014A (en) * 1990-06-08 2000-07-18 Corning Incorporated Engine exhaust system with reduced hydrocarbon emissions
US6171556B1 (en) 1992-11-12 2001-01-09 Engelhard Corporation Method and apparatus for treating an engine exhaust gas stream
US7226575B2 (en) 2004-11-30 2007-06-05 Chevron U.S.A. Inc. Boron-containing molecular sieve CHA
WO2007079038A2 (en) 2005-12-28 2007-07-12 Chevron U.S.A Inc. Molecular sieve ssz-74 composition of matter and synthesis thereof
US7282082B2 (en) 2004-11-29 2007-10-16 Chevron Usa, Inc. Gas separation using high-silica molecular sieve CHA
US7402297B2 (en) 2004-11-29 2008-07-22 Chevron U.S.A. Inc. High-silica molecular sieve CHA
US7462744B1 (en) 2004-11-30 2008-12-09 Chevron U.S.A. Inc. Synthesis of amines using boron-containing molecular sieve CHA
US7507393B2 (en) * 2007-03-20 2009-03-24 Chevron U. S. A. Inc. Boron-containing molecular sieve CHA
US7749473B2 (en) 2006-06-08 2010-07-06 Chevron U.S.A. Inc. Treatment of engine exhaust using molecular sieve SSZ-75
US7749471B2 (en) 2004-11-30 2010-07-06 Chevron U.S.A. Inc. Reduction of oxides of nitrogen in a gas stream using boron-containing molecular sieve CHA
US7762059B2 (en) 2005-12-28 2010-07-27 Chevron U.S.A. Inc. Treatment of engine exhaust using molecular sieve SSZ-74
WO2013154671A1 (en) 2012-04-12 2013-10-17 Chevron U.S.A. Inc. Processes using molecular sieve ssz-87
US8580228B2 (en) 2006-12-27 2013-11-12 Chevron U.S.A. Inc. Treatment of cold start engine exhaust
WO2014123610A1 (en) 2013-02-08 2014-08-14 Chevron U.S.A. Inc. Processes using molecular sieve ssz-85
EP2927039A1 (en) * 2014-04-01 2015-10-07 Inergy Automotive Systems Research (Société Anonyme) Vehicle storage system and convertor for use in such a system

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5269140A (en) * 1989-10-24 1993-12-14 Nichias Corporation Exhaust gas purifier for methanol-fueled engines
US5140811A (en) * 1989-10-27 1992-08-25 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification device in variable combination of absorbent and catalyst according to gas temperature
EP0424966A1 (en) * 1989-10-27 1991-05-02 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification device in variable combination of absorbent and catalyst according to gas temperature
US5331809A (en) * 1989-12-06 1994-07-26 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification system for an internal combustion engine
US5271914A (en) * 1990-04-04 1993-12-21 Tosoh Corporation Process for adsorbing the vapor of alcoholic fuels
US5125231A (en) * 1990-06-08 1992-06-30 Corning Incorporated Dual converter engine exhaust system for reducing hydrocarbon emissions
AU635644B2 (en) * 1990-06-08 1993-03-25 Corning Incorporated Dual converter engine exhaust system for reducing hydrocarbon emissions
US6089014A (en) * 1990-06-08 2000-07-18 Corning Incorporated Engine exhaust system with reduced hydrocarbon emissions
US5078979A (en) * 1990-07-20 1992-01-07 Uop Molecular sieve bed/catalyst to treat automotive exhaust
US5051244A (en) * 1990-07-20 1991-09-24 Uop Use of a molecular sieve bed to minimize emissions during cold start of internal combustion engines
US5207734A (en) * 1991-07-22 1993-05-04 Corning Incorporated Engine exhaust system for reduction of hydrocarbon emissions
US5577383A (en) * 1991-09-20 1996-11-26 Hitachi, Ltd. Apparatus for controlling internal combustion engine
US5379586A (en) * 1991-09-20 1995-01-10 Hitachi, Ltd. System for controlling oxygen concentration in exhaust gas and exhaust gas cleaning system employing the same
US5142864A (en) * 1991-09-30 1992-09-01 Uop Process for treating an engine exhaust stream employing a catalyst, an adsorbent bed and a turbocharger
US5365734A (en) * 1992-03-25 1994-11-22 Toyota Jidosha Kabushiki Kaisha NOx purification apparatus for an internal combustion engine
US5303547A (en) * 1992-04-15 1994-04-19 Amoco Corporation Emissions control system and method
US5609832A (en) * 1992-04-15 1997-03-11 Amoco Corporation Emissions control system and method
US5660800A (en) * 1992-04-15 1997-08-26 Amoco Corporation Emissions control system and method
US6171556B1 (en) 1992-11-12 2001-01-09 Engelhard Corporation Method and apparatus for treating an engine exhaust gas stream
US5531068A (en) * 1995-06-19 1996-07-02 Uop Combination catalyst/adsorber system for treating an engine exhaust gas stream
US7282082B2 (en) 2004-11-29 2007-10-16 Chevron Usa, Inc. Gas separation using high-silica molecular sieve CHA
US7402297B2 (en) 2004-11-29 2008-07-22 Chevron U.S.A. Inc. High-silica molecular sieve CHA
US7749471B2 (en) 2004-11-30 2010-07-06 Chevron U.S.A. Inc. Reduction of oxides of nitrogen in a gas stream using boron-containing molecular sieve CHA
US7462744B1 (en) 2004-11-30 2008-12-09 Chevron U.S.A. Inc. Synthesis of amines using boron-containing molecular sieve CHA
US7226575B2 (en) 2004-11-30 2007-06-05 Chevron U.S.A. Inc. Boron-containing molecular sieve CHA
WO2007079038A2 (en) 2005-12-28 2007-07-12 Chevron U.S.A Inc. Molecular sieve ssz-74 composition of matter and synthesis thereof
US7762059B2 (en) 2005-12-28 2010-07-27 Chevron U.S.A. Inc. Treatment of engine exhaust using molecular sieve SSZ-74
US7749473B2 (en) 2006-06-08 2010-07-06 Chevron U.S.A. Inc. Treatment of engine exhaust using molecular sieve SSZ-75
US8580228B2 (en) 2006-12-27 2013-11-12 Chevron U.S.A. Inc. Treatment of cold start engine exhaust
US9114362B2 (en) 2006-12-27 2015-08-25 Chevron U.S.A. Inc. Treatment of cold start engine exhaust
US7507393B2 (en) * 2007-03-20 2009-03-24 Chevron U. S. A. Inc. Boron-containing molecular sieve CHA
WO2013154671A1 (en) 2012-04-12 2013-10-17 Chevron U.S.A. Inc. Processes using molecular sieve ssz-87
WO2014123610A1 (en) 2013-02-08 2014-08-14 Chevron U.S.A. Inc. Processes using molecular sieve ssz-85
EP2927039A1 (en) * 2014-04-01 2015-10-07 Inergy Automotive Systems Research (Société Anonyme) Vehicle storage system and convertor for use in such a system

Also Published As

Publication number Publication date
BR8306309A (en) 1984-07-03
CA1205980A1 (en)

Similar Documents

Publication Publication Date Title
US8920756B2 (en) Silver promoted close-coupled NOx absorber
RU2623218C1 (en) Oxidation catalyst for internal combustion engine exhaust gas treatment
US9810118B2 (en) Catalyst system for the reduction of NOx and NH3 emissions
Farrauto et al. Catalytic converters: state of the art and perspectives
US4985210A (en) Exhaust gas purifying apparatus for automobile
JP4588824B2 (en) Catalyst for purification of diesel engine exhaust gas
US5768888A (en) Emission control system
US6397582B1 (en) Exhaust gas purification apparatus of internal combustion engine and catalyst for purifying exhaust gas of internal combustion engine
KR101060125B1 (en) Exhaust system for lean burn IC engines
US9810120B2 (en) Exhaust gas purifying system
RU2504668C2 (en) Exhaust system for ice running on lean mixes
JP5802260B2 (en) Method for reducing nitrous oxide in exhaust gas aftertreatment for lean burn engines
Bögner et al. Removal of nitrogen oxides from the exhaust of a lean-tune gasoline engine
DE69910605T2 (en) Stage reduction injection for improved nox reduction
EP1608854B1 (en) Exhaust-gas purification system for the selective catalytic reduction of nitrogen oxides in the lean exhaust gas of internal combustion engines and method of exhaust-gas purification
US6713030B1 (en) Process and apparatus for reducing the nitrogen oxide content in exhaust gases by the controlled addition of NH3
JP4381610B2 (en) Improvements in particulate control
KR20150087341A (en) Zoned catalyst on monolithic substrate
US6074973A (en) Catalyzed hydrocarbon trap material and method of making the same
DE19747670C1 (en) Exhaust gas cleaning system for internal combustion engine
JP5340305B2 (en) Method for treating nitrogen oxides in exhaust gas and system therefor
Miyoshi et al. Development of new concept three-way catalyst for automotive lean-burn engines
US5656244A (en) System for reducing NOx from mobile source engine exhaust
US6176079B1 (en) Process and apparatus for reducing nitrogen-oxide emissions in exhaust gas
US6938412B2 (en) Removing nitrogen oxides during a lean-burn engine cold start

Legal Events

Date Code Title Description
MKEX Expiry