US20050160721A1 - Internal combustion engine with NOx adsorber - Google Patents
Internal combustion engine with NOx adsorber Download PDFInfo
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- US20050160721A1 US20050160721A1 US11/087,169 US8716905A US2005160721A1 US 20050160721 A1 US20050160721 A1 US 20050160721A1 US 8716905 A US8716905 A US 8716905A US 2005160721 A1 US2005160721 A1 US 2005160721A1
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- exhaust
- reductant
- adsorber
- flow control
- control valve
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
- F01N3/0871—Regulation of absorbents or adsorbents, e.g. purging
- F01N3/0878—Bypassing absorbents or adsorbents
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust 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
- F01N13/011—Exhaust 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 purifying devices arranged in parallel
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
- F01N3/0828—Exhaust 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
- F01N3/0842—Nitrogen oxides
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/03—Adding substances to exhaust gases the substance being hydrocarbons, e.g. engine fuel
Definitions
- the present invention relates to an internal combustion engine that includes a NO x adsorber.
- a NO x adsorber or NO x trap is an aftertreatment device that stores or adsorbs NO x under lean conditions. Periodically, the NO x adsorber must be regenerated in order to continue collecting the NO x emissions. Under rich conditions, the NO x adsorber catalytically reduces the stored NO x . In a typical arrangement for a diesel engine, a post injection of a reductant such as diesel fuel directly into the exhaust gas creates the rich conditions required for NO x adsorber regeneration. In one arrangement, three seconds of regeneration are required for each one minute of NO x adsorber operation.
- an object of the present invention to provide an improved internal combustion engine with a NO x adsorber wherein the reductant is injected at a location slightly upstream, slightly downstream, or directly in the flow control valve to improve mixing of the reductant and the exhaust gas before entering the NO x adsorber.
- the pressure drop across the flow control valve results in turbulence that improves mixing of the injected liquid or gas reductant with the engine exhaust gas.
- good mixing can be achieved in a relatively short distance, which may result in aftertreatment device performance benefits and packaging benefits.
- the flow control valve controls the relative amounts of exhaust gas mixture that flow to the NO x adsorber and that are diverted to an alternate path.
- an internal combustion engine has a plurality of cylinders.
- the engine includes an intake manifold and an exhaust manifold.
- the engine further comprises a first exhaust path for receiving and routing exhaust gases, a first NO x adsorber located in the first exhaust path, and a second exhaust path for receiving and routing exhaust gases.
- the engine further comprises a flow control valve between the exhaust manifold and the first and second exhaust paths for controlling the relative amounts of exhaust gas flowing through the first and second exhaust paths.
- the engine further comprises a first injector for injecting a reductant into the exhaust gas stream.
- the first injector is located so as to inject the reductant at a location adjacent to the flow control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the first NO x adsorber.
- the reductant may or may not be fuel.
- the flow control valve may be implemented in any suitable way that controls the relative amounts of exhaust gas flowing through the first and second exhaust paths. That is, the term “flow control valve” encompasses any arrangement using at least one flow control valve for controlling the relative amounts of exhaust gas flowing through the first and second exhaust paths.
- the reductant injection adjacent to the flow control valve may occur at a location slightly upstream, slightly downstream, or directly in the flow control valve. Certain valve and injector arrangements route a lesser amount of exhaust gas to the NO x adsorber during regeneration than during normal operation. This approach allows a corresponding reduced amount of reductant to be injected. In a case where the reductant is fuel, such an approach limits the negative impact on fuel economy associated with the NO x adsorber regeneration process.
- the engine further comprises a second NO x adsorber located in the second exhaust path, and a second injector for injecting a reductant into the exhaust gas stream.
- the second injector is located so as to inject the reductant at a location adjacent to the control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the second NO x adsorber.
- Using multiple NO x adsorbers reduces the overall NO x level passed to the environment because only one NO x adsorber is regenerated at a time while remaining adsorber(s) remain active, and only a small portion of the total exhaust gas is routed to the regenerating NO x adsorber while routing the larger remaining portion of the exhaust gas to the active NO x adsorber(s).
- the invention comprehends the concept of one or more NO x adsorbers and various flow control valve arrangements that control the relative amounts of exhaust gas flowing through the various exhaust paths with a flow control valve improving the mixing of the exhaust gas and the reductant.
- an internal combustion engine with a plurality of cylinders includes an intake manifold and an exhaust manifold.
- the engine further comprises a first exhaust path for receiving and routing exhaust gases, a first NO x adsorber located in the first exhaust path, and a second exhaust path for receiving and routing exhaust gases.
- the engine further comprises a first flow control valve between the exhaust manifold and the first exhaust path and a second flow control valve between the exhaust manifold and the second exhaust path.
- the first and second flow control valves control the relative amounts of exhaust gas flowing through the first and second exhaust paths.
- the engine further comprises a first injector for injecting a reductant into the exhaust gas stream.
- the first injector is located so as to inject the reductant at a location adjacent to the first flow control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the first NO x adsorber.
- the engine further comprises a second NO x adsorber located in the second exhaust path and a second injector.
- the second injector is for injecting a reductant into the exhaust gas stream.
- the second injector is located so as to inject the reductant at a location adjacent to the second flow control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the second NO x adsorber.
- a method is provided.
- the method is for use in an internal combustion engine including a first NO x adsorber and a first injector.
- the method comprises operating the engine in an active mode, and, subsequently, operating the engine in a regenerative mode.
- the active mode exhaust gas flows through the first exhaust path and then through the first NO x adsorber such that the first NO x adsorber adsorbs NO x from the exhaust gas.
- a flow control valve causes a reduced amount of the exhaust gas to flow through the first exhaust path and through the first NO x adsorber and the reductant is injected into the reduced amount of the exhaust gas at a location adjacent to the flow control valve. This causes mixing of the reductant and the exhaust gas such that the first NO x adsorber catalytically reduces the previously adsorbed NO x to regenerate the first NO x adsorber.
- a method is provided.
- the method is for use in an internal combustion engine including a first NO x adsorber and a first injector, and a second NO x adsorber and a second injector.
- the method comprises operating the engine in an active mode, subsequently, operating the engine in a first regenerative mode, and, subsequently, operating the engine in a second regenerative mode.
- exhaust gas flows through the first exhaust path and through the first NO x adsorber such that the first NO x adsorber adsorbs NO x from the exhaust gas.
- exhaust gas flows through the second exhaust path and through the second NO x adsorber such that the second NO x adsorber adsorbs NO x from the exhaust gas.
- a flow control valve causes a reduced amount of the exhaust gas to flow through the first exhaust path and through the first NO x adsorber.
- the reductant is injected into the reduced amount of the exhaust gas at a location adjacent to the flow control valve. This causes mixing of the reductant and the exhaust gas such that the first NO x adsorber catalytically reduces the previously adsorbed NO x to regenerate the first NO x adsorber.
- a reduced amount of the exhaust gas flows through the second exhaust path and through the second NO x adsorber.
- the reductant is injected into the reduced amount of the exhaust gas at a location adjacent to a flow control valve. This causes mixing of the reductant and the exhaust gas such that the second NO x adsorber catalytically reduces the previously adsorbed NO x to regenerate the second NO x adsorber.
- the second adsorber remains active while the first adsorber is regenerated in the first regenerative mode. Further, preferably, the first adsorber remains active while the second adsorber is regenerated in the second regenerative mode.
- FIG. 1 illustrates an engine of the present invention including a single flow control valve and a single NO x adsorber
- FIG. 2 illustrates an engine of the present invention including two flow control valves and a single NO x adsorber
- FIG. 3 illustrates an engine of the present invention including a single flow control valve and two NO x adsorbers
- FIG. 4 illustrates an engine of the present invention including two flow control valves and two NO x adsorbers
- FIG. 5 illustrates a method of the present invention
- FIG. 6 illustrates a method of the present invention utilizing first and second NO x adsorbers.
- FIG. 1 illustrates an internal combustion engine including an engine block 10 with a plurality of cylinders 12 .
- the illustrated engine is a compression-ignition internal combustion engine such as a heavy-duty diesel engine. Cylinders 12 receive pressurized fuel from a fuel supply in a known manner.
- the engine includes an intake manifold 14 and an exhaust manifold 16 .
- a flow control valve 18 is located between exhaust manifold 16 and first and second exhaust paths 20 and 22 , respectively. Flow control valve 18 controls the relative amounts of exhaust gas flowing through the first exhaust path 20 and the second exhaust path 22 .
- a NO x adsorber 24 is located in first exhaust path 20 .
- An injector 26 is for injecting a reductant such as fuel into the exhaust gas stream. Injector 26 injects the reductant at a location adjacent to flow control valve 18 to cause mixing of the reductant and the exhaust gas and to allow regeneration of NO x adsorber 24 .
- NO x adsorber 24 In operation, when NO x adsorber 24 is active, substantially all exhaust flow is directed by flow control valve 18 to first exhaust path 20 and in the presence of the lean exhaust gas mixture, NO x adsorber 24 adsorbs or traps NO x . Periodically, NO x adsorber 24 must be regenerated. Regeneration takes place by injector 26 injecting the reductant into first exhaust path 20 to create a richer exhaust gas mixture that causes NO x adsorber 24 to catalytically reduce the stored NO x . During the regeneration process, flow control valve 18 directs only a reduced portion of the total exhaust gas flow to first exhaust path 20 while diverting the remaining portion of exhaust gas flow to second exhaust path 22 . In this way, the amount of reductant required to create the rich mixture for regeneration is reduced.
- this approach reduces the negative effects on fuel economy associated with regeneration of NO x adsorber 24 . It may be desirable to modify the fuel injection strategy during regeneration to reduce the amount of NO x diverted through second exhaust path 22 where there is no adsorber.
- FIG. 2 illustrates an embodiment similar to the embodiment of FIG. 1 but including first and second control valves 30 and 32 , respectively.
- Flow control valves 30 and 32 control the relative amounts of exhaust gas flowing through first exhaust path 20 and second exhaust path 22 .
- FIG. 3 illustrates an embodiment including a single flow control valve 18 and first and second NO x adsorbers 24 and 36 , respectively.
- First and second injectors 26 and 34 are associated with the first and second NO x adsorbers 24 and 36 , respectively.
- Flow control valve 18 controls the relative amounts of exhaust gas flowing through first exhaust path 20 and second exhaust path 22 .
- This embodiment allows NO x adsorbers 24 and 36 to be alternately regenerated such that the main portion of the exhaust gas flow is always being treated by one or the other NO x adsorber. For example, when both NO x adsorber 24 and NO x adsorber 36 are active, flow control valve 18 may pass half of the total exhaust flow to each of first and second exhaust paths 20 and 22 , respectively.
- flow control valve 18 may divert a majority of the exhaust gas to NO x adsorber 36 for aftertreatment while sending only a reduced portion of the exhaust gas flow along first path 20 to NO x adsorber 24 . In this way, the amount of reductant injected by injector 26 to create the required rich mixture is reduced which has significant effects on fuel economy when the reductant is fuel.
- FIG. 4 illustrates an embodiment similar to the embodiment of FIG. 3 but including first and second control valves 30 and 32 , respectively.
- Flow control valves 30 and 32 control the relative amounts of exhaust gas flowing through the first exhaust path 20 and second exhaust path 22 .
- FIG. 5 illustrates a method of the present invention.
- the engine is operated in an active mode where exhaust gas flows through a first exhaust path and through a first NO x adsorber such that the first NO x adsorber adsorbs NO x from the exhaust gas.
- the engine is operated in a regenerative mode. In the regenerative mode, a reduced amount of the exhaust gas flows through the first exhaust path and through the first NO x adsorber, and the reductant is injected into the reduced amount of the exhaust gas at a location adjacent to a flow control valve to cause mixing of the reductant and the exhaust gas. This causes the first NO x adsorber to catalytically reduce the previously adsorbed NO x to regenerate the first NO x adsorber.
- FIG. 6 a method involving two NO x adsorbers is illustrated.
- the engine is operated in the active mode, adsorbing NO x with both NO x adsorbers.
- the engine is operated in a first regenerative mode to regenerate the first NO x adsorber by injecting reductant adjacent to a flow control valve while the second NO x adsorber remains active.
- the engine is operated in a second regenerative mode to regenerate the second NO x adsorber by injecting reductant adjacent to a flow control valve while the first NO x adsorber remains active.
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- Chemical & Material Sciences (AREA)
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- General Engineering & Computer Science (AREA)
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
An internal combustion engine includes first and second exhaust paths, and a first NOx adsorber located in the first exhaust path. A flow control valve controls the relative amounts of exhaust gas flowing through the first and second exhaust paths. A first injector injects a reductant into the exhaust gas stream. The injector is located so as to inject the reductant at a location adjacent to the flow control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the first NOx adsorber.
Description
- This application is a divisional of U.S. application Ser. No. 10/700,903 filed Nov. 4, 2003.
- 1. Field of the Invention
- The present invention relates to an internal combustion engine that includes a NOx adsorber.
- 2. Background Art
- The heavy-duty engine business is extremely competitive. Increasing demands are being placed on engine manufacturers to design and build engines that provide better engine performance, improved reliability, and greater durability while meeting more stringent emission and noise requirements. One approach to meet more stringent emission requirements is to utilize a NOx adsorber. NOx are believed to be an environmental hazard, and are created when combustion temperatures become excessive. NOx are a particular concern in the turbocharged diesel engine.
- A NOx adsorber or NOx trap is an aftertreatment device that stores or adsorbs NOx under lean conditions. Periodically, the NOx adsorber must be regenerated in order to continue collecting the NOx emissions. Under rich conditions, the NOx adsorber catalytically reduces the stored NOx. In a typical arrangement for a diesel engine, a post injection of a reductant such as diesel fuel directly into the exhaust gas creates the rich conditions required for NOx adsorber regeneration. In one arrangement, three seconds of regeneration are required for each one minute of NOx adsorber operation.
- For good regeneration, it is desired that the fuel (or other injected substance) be well mixed with the exhaust flow before entering the aftertreatment device. To improve the mixing, the current practice is to inject at an elbow, allow a long length of piping after the fuel is injected before entering the aftertreatment device, or a combination of these or other mixing schemes. Further background information may be found in U.S. Pat. Nos. 4,505,106; 6,442,933; 6,523,342; and 4,359,862.
- For the foregoing reasons, there is a need to address the issue of mixing the reductant with the exhaust gas before entering the aftertreatment device.
- It is, therefore, an object of the present invention to provide an improved internal combustion engine with a NOx adsorber wherein the reductant is injected at a location slightly upstream, slightly downstream, or directly in the flow control valve to improve mixing of the reductant and the exhaust gas before entering the NOx adsorber. The pressure drop across the flow control valve results in turbulence that improves mixing of the injected liquid or gas reductant with the engine exhaust gas. Advantageously, good mixing can be achieved in a relatively short distance, which may result in aftertreatment device performance benefits and packaging benefits. The flow control valve controls the relative amounts of exhaust gas mixture that flow to the NOx adsorber and that are diverted to an alternate path.
- In carrying out the above object, an internal combustion engine is provided. The internal combustion engine has a plurality of cylinders. The engine includes an intake manifold and an exhaust manifold. The engine further comprises a first exhaust path for receiving and routing exhaust gases, a first NOx adsorber located in the first exhaust path, and a second exhaust path for receiving and routing exhaust gases. The engine further comprises a flow control valve between the exhaust manifold and the first and second exhaust paths for controlling the relative amounts of exhaust gas flowing through the first and second exhaust paths. The engine further comprises a first injector for injecting a reductant into the exhaust gas stream. The first injector is located so as to inject the reductant at a location adjacent to the flow control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the first NOx adsorber.
- It is appreciated that the reductant may or may not be fuel. It is appreciated that the flow control valve may be implemented in any suitable way that controls the relative amounts of exhaust gas flowing through the first and second exhaust paths. That is, the term “flow control valve” encompasses any arrangement using at least one flow control valve for controlling the relative amounts of exhaust gas flowing through the first and second exhaust paths. It is appreciated that the reductant injection adjacent to the flow control valve may occur at a location slightly upstream, slightly downstream, or directly in the flow control valve. Certain valve and injector arrangements route a lesser amount of exhaust gas to the NOx adsorber during regeneration than during normal operation. This approach allows a corresponding reduced amount of reductant to be injected. In a case where the reductant is fuel, such an approach limits the negative impact on fuel economy associated with the NOx adsorber regeneration process.
- In some embodiments, the engine further comprises a second NOx adsorber located in the second exhaust path, and a second injector for injecting a reductant into the exhaust gas stream. The second injector is located so as to inject the reductant at a location adjacent to the control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the second NOx adsorber. Using multiple NOx adsorbers reduces the overall NOx level passed to the environment because only one NOx adsorber is regenerated at a time while remaining adsorber(s) remain active, and only a small portion of the total exhaust gas is routed to the regenerating NOx adsorber while routing the larger remaining portion of the exhaust gas to the active NOx adsorber(s). Again, it is appreciated that the invention comprehends the concept of one or more NOx adsorbers and various flow control valve arrangements that control the relative amounts of exhaust gas flowing through the various exhaust paths with a flow control valve improving the mixing of the exhaust gas and the reductant.
- Further, in carrying out the present invention, an internal combustion engine with a plurality of cylinders is provided. The engine includes an intake manifold and an exhaust manifold. The engine further comprises a first exhaust path for receiving and routing exhaust gases, a first NOx adsorber located in the first exhaust path, and a second exhaust path for receiving and routing exhaust gases. The engine further comprises a first flow control valve between the exhaust manifold and the first exhaust path and a second flow control valve between the exhaust manifold and the second exhaust path. The first and second flow control valves control the relative amounts of exhaust gas flowing through the first and second exhaust paths. The engine further comprises a first injector for injecting a reductant into the exhaust gas stream. The first injector is located so as to inject the reductant at a location adjacent to the first flow control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the first NOx adsorber.
- In some embodiments, the engine further comprises a second NOx adsorber located in the second exhaust path and a second injector. The second injector is for injecting a reductant into the exhaust gas stream. The second injector is located so as to inject the reductant at a location adjacent to the second flow control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the second NOx adsorber.
- Still further, in carrying out the present invention, a method is provided. The method is for use in an internal combustion engine including a first NOx adsorber and a first injector. The method comprises operating the engine in an active mode, and, subsequently, operating the engine in a regenerative mode. In the active mode, exhaust gas flows through the first exhaust path and then through the first NOx adsorber such that the first NOx adsorber adsorbs NOx from the exhaust gas. In the regenerative mode, a flow control valve causes a reduced amount of the exhaust gas to flow through the first exhaust path and through the first NOx adsorber and the reductant is injected into the reduced amount of the exhaust gas at a location adjacent to the flow control valve. This causes mixing of the reductant and the exhaust gas such that the first NOx adsorber catalytically reduces the previously adsorbed NOx to regenerate the first NOx adsorber.
- Still further, in carrying out the present invention, a method is provided. The method is for use in an internal combustion engine including a first NOx adsorber and a first injector, and a second NOx adsorber and a second injector. The method comprises operating the engine in an active mode, subsequently, operating the engine in a first regenerative mode, and, subsequently, operating the engine in a second regenerative mode. In the active mode, exhaust gas flows through the first exhaust path and through the first NOx adsorber such that the first NOx adsorber adsorbs NOx from the exhaust gas. Further, in the active mode, exhaust gas flows through the second exhaust path and through the second NOx adsorber such that the second NOx adsorber adsorbs NOx from the exhaust gas.
- In the first regenerative mode, a flow control valve causes a reduced amount of the exhaust gas to flow through the first exhaust path and through the first NOx adsorber. The reductant is injected into the reduced amount of the exhaust gas at a location adjacent to the flow control valve. This causes mixing of the reductant and the exhaust gas such that the first NOx adsorber catalytically reduces the previously adsorbed NOx to regenerate the first NOx adsorber.
- In the second regenerative mode, a reduced amount of the exhaust gas flows through the second exhaust path and through the second NOx adsorber. The reductant is injected into the reduced amount of the exhaust gas at a location adjacent to a flow control valve. This causes mixing of the reductant and the exhaust gas such that the second NOx adsorber catalytically reduces the previously adsorbed NOx to regenerate the second NOx adsorber.
- In a preferred method, the second adsorber remains active while the first adsorber is regenerated in the first regenerative mode. Further, preferably, the first adsorber remains active while the second adsorber is regenerated in the second regenerative mode.
- The above object and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the preferred embodiments when taken in connection with the accompanying drawings.
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FIG. 1 illustrates an engine of the present invention including a single flow control valve and a single NOx adsorber; -
FIG. 2 illustrates an engine of the present invention including two flow control valves and a single NOx adsorber; -
FIG. 3 illustrates an engine of the present invention including a single flow control valve and two NOx adsorbers; -
FIG. 4 illustrates an engine of the present invention including two flow control valves and two NOx adsorbers; -
FIG. 5 illustrates a method of the present invention; and -
FIG. 6 illustrates a method of the present invention utilizing first and second NOx adsorbers. -
FIG. 1 illustrates an internal combustion engine including anengine block 10 with a plurality ofcylinders 12. The illustrated engine is a compression-ignition internal combustion engine such as a heavy-duty diesel engine.Cylinders 12 receive pressurized fuel from a fuel supply in a known manner. The engine includes anintake manifold 14 and anexhaust manifold 16. Aflow control valve 18 is located betweenexhaust manifold 16 and first andsecond exhaust paths Flow control valve 18 controls the relative amounts of exhaust gas flowing through thefirst exhaust path 20 and thesecond exhaust path 22. A NOxadsorber 24 is located infirst exhaust path 20. Aninjector 26 is for injecting a reductant such as fuel into the exhaust gas stream.Injector 26 injects the reductant at a location adjacent to flowcontrol valve 18 to cause mixing of the reductant and the exhaust gas and to allow regeneration of NOxadsorber 24. - In operation, when NOx
adsorber 24 is active, substantially all exhaust flow is directed byflow control valve 18 tofirst exhaust path 20 and in the presence of the lean exhaust gas mixture, NOxadsorber 24 adsorbs or traps NOx. Periodically, NOxadsorber 24 must be regenerated. Regeneration takes place byinjector 26 injecting the reductant intofirst exhaust path 20 to create a richer exhaust gas mixture that causes NOxadsorber 24 to catalytically reduce the stored NOx. During the regeneration process, flowcontrol valve 18 directs only a reduced portion of the total exhaust gas flow tofirst exhaust path 20 while diverting the remaining portion of exhaust gas flow tosecond exhaust path 22. In this way, the amount of reductant required to create the rich mixture for regeneration is reduced. Particularly, when the reductant is fuel, this approach reduces the negative effects on fuel economy associated with regeneration of NOxadsorber 24. It may be desirable to modify the fuel injection strategy during regeneration to reduce the amount of NOx diverted throughsecond exhaust path 22 where there is no adsorber. -
FIG. 2 illustrates an embodiment similar to the embodiment ofFIG. 1 but including first andsecond control valves Flow control valves first exhaust path 20 andsecond exhaust path 22. -
FIG. 3 illustrates an embodiment including a singleflow control valve 18 and first and second NOx adsorbers 24 and 36, respectively. First andsecond injectors Flow control valve 18 controls the relative amounts of exhaust gas flowing throughfirst exhaust path 20 andsecond exhaust path 22. This embodiment allows NOxadsorbers adsorber 24 and NOxadsorber 36 are active,flow control valve 18 may pass half of the total exhaust flow to each of first andsecond exhaust paths adsorber 24 requires regeneration,flow control valve 18 may divert a majority of the exhaust gas to NOxadsorber 36 for aftertreatment while sending only a reduced portion of the exhaust gas flow alongfirst path 20 to NOxadsorber 24. In this way, the amount of reductant injected byinjector 26 to create the required rich mixture is reduced which has significant effects on fuel economy when the reductant is fuel. -
FIG. 4 illustrates an embodiment similar to the embodiment ofFIG. 3 but including first andsecond control valves Flow control valves first exhaust path 20 andsecond exhaust path 22. -
FIG. 5 illustrates a method of the present invention. At block 40, the engine is operated in an active mode where exhaust gas flows through a first exhaust path and through a first NOx adsorber such that the first NOx adsorber adsorbs NOx from the exhaust gas. Atblock 42, subsequently, the engine is operated in a regenerative mode. In the regenerative mode, a reduced amount of the exhaust gas flows through the first exhaust path and through the first NOx adsorber, and the reductant is injected into the reduced amount of the exhaust gas at a location adjacent to a flow control valve to cause mixing of the reductant and the exhaust gas. This causes the first NOx adsorber to catalytically reduce the previously adsorbed NOx to regenerate the first NOx adsorber. - In
FIG. 6 , a method involving two NOx adsorbers is illustrated. Atblock 44, the engine is operated in the active mode, adsorbing NOx with both NOx adsorbers. Atblock 46, the engine is operated in a first regenerative mode to regenerate the first NOx adsorber by injecting reductant adjacent to a flow control valve while the second NOx adsorber remains active. Atblock 48, the engine is operated in a second regenerative mode to regenerate the second NOx adsorber by injecting reductant adjacent to a flow control valve while the first NOx adsorber remains active. - While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
Claims (4)
1. An internal combustion engine with a plurality of cylinders, the engine including an intake manifold and an exhaust manifold, the engine further comprising:
a first exhaust path for receiving and routing exhaust gases;
a first NOx adsorber located in the first exhaust path;
a second exhaust path for receiving and routing exhaust gases;
a first flow control valve between the exhaust manifold and the first exhaust path and a second flow control valve between the exhaust manifold and the second exhaust path, the first and second flow control valves controlling the relative amounts of exhaust gas flowing through the first and second exhaust paths; and
a first injector for injecting a reductant into the exhaust gas stream, the first injector being located so as to inject the reductant at a location immediately adjacent to the first flow control valve;
wherein there is a pressure drop across the first flow control valve that results in turbulent flow in a region immediately adjacent to the flow control valve that includes the reductant injection location, thereby causing mixing of the reductant and the exhaust gas in a relatively short distance and to allow regeneration of the first NOx adsorber.
2. The internal combustion engine of claim 1 further comprising:
a second NOx adsorber located in the second exhaust path; and
a second injector for injecting a reductant into the exhaust gas stream, the second injector being located so as to inject the reductant at a location adjacent to the second flow control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the second NOx adsorber.
3. The internal combustion engine of claim 2 wherein the second injector is located so as to inject the reductant at a location immediately upstream of the second flow control valve along the second exhaust path.
4. The internal combustion engine of claim 1 wherein the first injector is located so as to inject the reductant at a location immediately upstream of the first flow control valve along the first exhaust path.
Priority Applications (1)
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US11/087,169 US20050160721A1 (en) | 2003-11-04 | 2005-03-23 | Internal combustion engine with NOx adsorber |
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Application Number | Priority Date | Filing Date | Title |
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US10/700,903 US6934622B2 (en) | 2003-11-04 | 2003-11-04 | Internal combustion engine with NOx adsorber |
US11/087,169 US20050160721A1 (en) | 2003-11-04 | 2005-03-23 | Internal combustion engine with NOx adsorber |
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US10/700,903 Division US6934622B2 (en) | 2003-11-04 | 2003-11-04 | Internal combustion engine with NOx adsorber |
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US20050160721A1 true US20050160721A1 (en) | 2005-07-28 |
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US10/700,903 Expired - Fee Related US6934622B2 (en) | 2003-11-04 | 2003-11-04 | Internal combustion engine with NOx adsorber |
US11/087,169 Abandoned US20050160721A1 (en) | 2003-11-04 | 2005-03-23 | Internal combustion engine with NOx adsorber |
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US10/700,903 Expired - Fee Related US6934622B2 (en) | 2003-11-04 | 2003-11-04 | Internal combustion engine with NOx adsorber |
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Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060254260A1 (en) * | 2005-05-16 | 2006-11-16 | Arvinmeritor Emissions Technologies Gmbh | Method and apparatus for piezoelectric injection of agent into exhaust gas for use with emission abatement device |
US7571602B2 (en) | 2005-05-19 | 2009-08-11 | Gm Global Technology Operations, Inc. | Exhaust aftertreatment system and method of use for lean burn internal combustion engines |
JP4781031B2 (en) * | 2005-07-19 | 2011-09-28 | トヨタ自動車株式会社 | Control device for exhaust purification system |
US7591132B2 (en) * | 2006-09-20 | 2009-09-22 | Gm Global Technology Operations, Inc. | Apparatus and method to inject a reductant into an exhaust gas feedstream |
US7469531B2 (en) * | 2006-09-20 | 2008-12-30 | Gm Global Technology Operations, Inc. | Method and apparatus to control injection of a reductant into an exhaust gas feedstream |
WO2009007775A1 (en) * | 2007-07-12 | 2009-01-15 | Renault Trucks | Exhaust arrangement for a vehicle exhaust line |
US11428181B2 (en) * | 2020-03-25 | 2022-08-30 | Cummins Inc. | Systems and methods for ultra-low NOx cold start warmup control and fault diagnosis |
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- 2003-11-04 US US10/700,903 patent/US6934622B2/en not_active Expired - Fee Related
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Also Published As
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US6934622B2 (en) | 2005-08-23 |
US20050091967A1 (en) | 2005-05-05 |
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