US20090178396A1

US20090178396A1 - EGR catalyzation with reduced EGR heating

Info

Publication number: US20090178396A1
Application number: US12/286,001
Authority: US
Inventors: Aleksey Yezerets; Neal W. Currier; Bradlee J. Stroia; Haiying Chen; Howard Hess; Mahesh Konduru
Original assignee: Cummins Inc
Current assignee: Cummins Inc
Priority date: 2008-01-11
Filing date: 2008-09-26
Publication date: 2009-07-16
Also published as: WO2009089074A2; CN101970847A; WO2009089074A3; EP2245293A4; EP2245293A2

Abstract

One embodiment is a unique system of EGR catalyzation with reduced EGR heating. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS:

The present application claims priority to U.S. Provisional Patent Application No. 61/010,733 filed Jan. 11, 2008, which is incorporated herein by reference in its entirety.

BACKGROUND

Exhaust gas recirculation (“EGR”) may be used in connection with internal combustion engines to reduce emissions or for other purposes. Present approaches to EGR suffer from a variety of drawbacks, limitations, disadvantages and problems including, for example, those respecting reduction or prevention of deposits such as carbonaceous deposits, reducing or avoiding heating of EGR, and others. There is a need for the unique and inventive apparatuses, systems, and methods disclosed herein.

SUMMARY

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic of a system including an internal combustion engine.

FIG. 2 is a schematic of a cooled EGR system.

FIG. 3 is a schematic of a cooled EGR system.

FIG. 4 is a schematic of a cooled EGR system.

FIG. 5 is a schematic of a vehicle including an engine and a cooled EGR system.

DETAILED DESCRIPTION

For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the figures and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby created, and that the invention includes and protects such alterations and modifications to the illustrated embodiments, and such further applications of the principles of the invention illustrated therein as would occur to one skilled in the art to which the invention relates.
With reference to FIG. 1, there is illustrated a system 10 including an internal combustion engine 12 having an intake manifold 14 with an intake conduit 20 coupled thereto. The intake conduit 20 is coupled to an intake 22 which supplies ambient air to intake conduit 20. Preferably, the intake conduit 20 is coupled to an outlet of compressor 16 of turbocharger 18 or of another type of supercharger. Compressor 16 receives fresh air from intake 22 and outputs compressed air. System 10 may include an air throttle 66 disposed between the intake manifold 14 and the intake conduit 22. System 10 preferably includes a charge air cooler 24 disposed downstream from compressor 16 and which cools compressed air received from compressor 16.
Engine 12 further includes an exhaust manifold 30 having an exhaust conduit 32 coupled thereto. Exhaust flow from conduit 32 drives a turbine 26 of turbocharger 18 which is mechanically coupled to compressor 16 via drive shaft 28. Turbine 26 preferably outlets to an aftertreatment system or to ambient via the exhaust conduit 34. A portion of the exhaust from conduit 32 may be recirculated via EGR conduit 38. The rate of exhaust gas recirculation or EGR may be controlled by EGR valve 36 which is illustrated as being upstream of EGR cooler 40, but could also be positioned downstream from EGR cooler 40, or intermediate EGR cooler 40 and catalyst unit 90. Regardless of the location or presence of EGR valve 36, catalyst unit 90 is preferably positioned at a location upstream of EGR cooler 40. Catalyst unit 90 preferably includes a non-oxidizing catalyst or a mildly oxidizing catalyst which are referred to herein as a substantially non-oxidizing catalyst. Substantially non-oxidizing catalysts are catalysts which are operable to catalyze one or more chemical reactions which decrease the molecular weight of hydrocarbon compounds present in exhaust gas without increasing the temperature of the exhaust gas or with a reduced temperature increase relative to that which would occur with an oxidizing catalyst. Examples of substantially non-oxidizing catalysts include solid acid catalysts and zeolite catalysts. Hydrocarbon cracking is an exemplary reaction which is catalyzed by substantially non-oxidizing catalysts.
System 10 also preferably includes a control circuit 42 that is microprocessor-based and operable to control and manage the operation of engine 12, for example, an engine control module (ECM), engine control unit (ECU). Control circuit 42 includes a number of inputs for receiving signals from various sensors or sensing systems associated with system 10. For example, system 10 preferably includes an engine speed sensor 44 electrically connected to an engine speed input, ES, of control circuit 42 via signal path 46. Engine speed sensor 44 is operable to sense rotational speed of the engine 12 and produce an engine speed signal on signal path 46 indicative of engine rotational speed. System 10 also preferably includes a mass air flow sensor 48 disposed in fluid communication with the intake conduit 20 of engine 12, and electrically connected to a mass flow of air input (MFA) of control circuit 42 via signal path 50. Mass air flow sensor 48 is operable to produce a mass flow rate signal on signal path 50 indicative of the mass flow rate of fresh air flowing into the intake conduit 20. System 10 also preferably includes a lambda sensor 80 disposed in fluid communication with exhaust conduit 34 and electrically connected to a lambda input of control circuit 42 via signal path 82, as shown in FIG. 1. Control circuit 42 also preferably includes a number of outputs for controlling one or more fluid handling mechanisms associated with system 10. For example, EGR valve 36 includes an EGR valve actuator 62 electrically connected to an EGR valve control output (EGRC) of control circuit 42 via signal path 63. Control circuit 42 is operable to produce an EGR valve control signal on signal path 63, and EGR valve actuator 62 is responsive to the EGR valve control signal on signal path 63 to control the position of EGR valve 36 relative to a reference position. In addition, air throttle 66 includes an air throttle actuator 68 electrically connected to an air throttle control output (ATC) of control circuit 42 via signal path 70. Control circuit 42 is operable to produce an air throttle control signal on signal path 70, and air throttle actuator 68 is responsive to the air throttle control signal on signal path 70 to control the position of air throttle 66 relative to a reference position. System 10 also preferably includes a fueling system 72 electrically connected to a fuel command output (FC) of control computer 42 via signal path 74. Fueling system 72 is responsive to fueling control signals produced by control circuit 42 on signal path 74 to supply fuel to engine 12, and control circuit 42 is operable to produce such fueling control signals.
With reference to FIG. 2 there is illustrated an exemplary cooled EGR system 200 which includes an EGR valve 236 which is flow coupled to a substantially non-oxidizing catalyst unit 290 which is flow coupled to an EGR cooler 240. During operation exhaust flows from an engine, exhaust manifold, exhaust conduit or other exhaust source to EGR valve 236 which is preferably operable to control the amount or rate of exhaust flow but could also simply be an on/off valve. Exhaust next flows to substantially non-oxidizing catalyst unit 290 which includes one or more substantially non-oxidizing catalysts operable to catalyze one or more reactions of hydrocarbons in the exhaust in order to convert higher molecular weight hydrocarbons into lower molecular weight hydrocarbons while avoiding, minimizing, controlling or reducing any temperature increase of the exhaust owing to the catalyzed reaction(s). Exhaust then flows to EGR cooler 240 which cools the exhaust. From EGR cooler 240, exhaust may optionally flow through one or more additional coolers, and may be mixed with intake or charge air before being provided to an intake manifold or directly to one or more engine cylinders.
With reference to FIG. 3 there is illustrated an exemplary cooled EGR system 300 which includes a substantially non-oxidizing catalyst unit 390 which is flow coupled to an EGR cooler 340 which is flow coupled to an EGR valve 336. During operation exhaust flows from an engine, exhaust manifold, exhaust conduit or other exhaust source to substantially non-oxidizing catalyst unit 290 which includes one or more substantially non-oxidizing catalysts operable to catalyze one or more reactions of hydrocarbons in the exhaust in order to convert higher molecular weight hydrocarbons into lower molecular weight hydrocarbons while avoiding, minimizing, controlling or reducing any temperature increase of the exhaust owing to the catalyzed reaction(s). Exhaust next flows to EGR cooler 340 which cools the exhaust. Exhaust then flows to EGR valve 336 which is preferably operable to control the amount or rate of exhaust flow but could also simply be an on/off valve. From EGR valve 336, exhaust may optionally flow through one or more additional coolers and may be mixed with intake or charge air before being provided to an intake manifold or directly to one or more engine cylinders.
With reference to FIG. 4 there is illustrated an exemplary cooled EGR system 400 which includes a substantially non-oxidizing catalyst unit 490 which is flow coupled to an EGR valve 436 which is flow coupled to an EGR cooler 440. During operation exhaust flows from an engine, exhaust manifold, exhaust conduit or other exhaust source to substantially non-oxidizing catalyst unit 490 which includes one or more substantially non-oxidizing catalysts operable to catalyze one or more reactions of hydrocarbons in the exhaust in order to convert higher molecular weight hydrocarbons into lower molecular weight hydrocarbons while avoiding, minimizing, controlling or reducing any temperature increase of the exhaust owing to the catalyzed reaction(s). Exhaust next flows to EGR valve 436 which is preferably operable to selectably control the amount or rate of exhaust flow but could also simply be an on/off valve. Exhaust then flows to EGR cooler 440 which cools the exhaust. From EGR cooler 440 exhaust may optionally flow through one or more additional coolers and may be mixed with intake or charge air before being provided to an intake manifold or directly to one or more engine cylinders.
With reference to FIG. 5, there is illustrated a vehicle 500. Vehicle 500 is shown as a semi tractor, but could also be a variety of types of vehicles, for example, light duty trucks, medium duty trucks, heavy duty trucks, buses, cars, motorhomes, fire and emergency vehicles, construction vehicles, boats and other marine vehicles, and rail vehicles such as locomotives. Vehicle 500 includes an engine 540, which is preferably a diesel engine but could be a spark ignition or other type of internal combustion engine, and a cooled EGR system 530 which preferably includes one or more EGR coolers operable to cool EGR to provided to engine 440, one or more substantially non-oxidizing catalyst units which could be the same as or similar to those described above, and one or more valves, pumps or other EGR controls. Further embodiments contemplate that engine 540 could be used in other applications including, for example, in generator sets, or industrial, mining, or oil and gas equipment.
As is evident from the figures and text presented above, a variety of embodiments according to the present invention are contemplated. Certain exemplary embodiments include a system comprising an EGR cooler operable to receive EGR gas at a first temperature and output EGR gas at a second temperature, the first temperature being greater than the second temperature; and a substantially non-oxidizing catalyst unit configured to intake EGR gas at an intake and output EGR gas at an output; wherein the EGR cooler and the substantially non-oxidizing catalyst unit are flow coupled and the substantially non-oxidizing catalyst unit is positioned upstream of the EGR cooler. In further exemplary embodiments the substantially non-oxidizing catalyst unit is operable to catalyze hydrocarbon cracking; the substantially non-oxidizing catalyst unit includes a solid acid catalyst; the substantially non-oxidizing catalyst unit includes a zeolite catalyst composition; the substantially non-oxidizing catalyst unit is operable to catalyze a reaction of hydrocarbons without increasing the temperature of EGR gas within the substantially non-oxidizing catalyst unit; and/or the substantially non-oxidizing catalyst unit is operable to catalyze a reaction of hydrocarbons while increasing the temperature of EGR gas within the substantially non-oxidizing catalyst unit by less than about 10 degrees centigrade. Further exemplary embodiments include an internal combustion engine and an exhaust manifold, the exhaust manifold being in fluid communication with the intake of the substantially non-oxidizing catalyst unit.
Certain exemplary embodiments include a system comprising an engine; an EGR conduit flow coupled the engine to receive exhaust gas therefrom; means for reducing molecular weight of hydrocarbon molecules in exhaust gas flow coupled to the EGR conduit; and means for cooling the EGR flow coupled to the means for reducing molecular weight of hydrocarbon molecules in exhaust gas. In further exemplary embodiments the means for cooling the EGR includes an engine coolant cooled EGR cooler; the means for reducing molecular weight of hydrocarbon molecules in exhaust gas includes a zeolite catalyst; the means for reducing molecular weight of hydrocarbon molecules in exhaust gas includes a hydrocarbon cracking catalyst; and/or the means for reducing molecular weight of hydrocarbon molecules in exhaust gas includes a solid acid catalyst. In further exemplary embodiments the engine is a diesel engine; and/or the diesel engine is configured to be the prime mover of a vehicle.
Certain exemplary embodiments include a method comprising operating an internal combustion engine to produce exhaust including one or more hydrocarbon compounds; treating a portion of the exhaust with a substantially non-oxidizing catalyst effective to reduce the molecular weight of the one or more hydrocarbon compounds; cooling the portion of the exhaust; and providing the portion of the exhaust to an intake of the internal combustion engine. In further exemplary embodiments the treating a portion of the exhaust with a substantially non-oxidizing catalyst effective to reduce the molecular weight of the one or more hydrocarbon compounds includes a hydrocarbon cracking reaction; the treating a portion of the exhaust with a substantially non-oxidizing catalyst effective to reduce the molecular weight of the one or more hydrocarbon compounds includes exposing the one or more hydrocarbon compounds to a hydrocarbon cracking catalyst; the treating a portion of the exhaust with a substantially non-oxidizing catalyst effective to reduce the molecular weight of the one or more hydrocarbon compounds includes exposing the one or more hydrocarbon compounds to a solid acid catalyst; the treating a portion of the exhaust with a substantially non-oxidizing catalyst effective to reduce the molecular weight of the one or more hydrocarbon compounds includes exposing the one or more hydrocarbon compounds to a zeolite catalyst; and/or the treating a portion of the exhaust with a substantially non-oxidizing catalyst occurs in a single catalyst unit positioned upstream from an EGR cooler.
While exemplary embodiments of the invention have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicate that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.

Claims

1. A system comprising:

an EGR cooler operable to receive EGR gas at a first temperature and output EGR gas at a second temperature, the first temperature being greater than the second temperature; and

a substantially non-oxidizing catalyst unit configured to intake EGR gas at an intake and output EGR gas at an output;

wherein the EGR cooler and the substantially non-oxidizing catalyst unit are flow coupled and the substantially non-oxidizing catalyst unit is positioned upstream of the EGR cooler.

2. A system according to claim 1 wherein the substantially non-oxidizing catalyst unit is operable to catalyze hydrocarbon cracking.

3. A system according to claim 1 wherein the substantially non-oxidizing catalyst unit includes a solid acid catalyst.

4. A system according to claim 1 wherein the substantially non-oxidizing catalyst unit includes a zeolite catalyst composition.

5. A system according to claim 1 wherein the substantially non-oxidizing catalyst unit is operable to catalyze a reaction of hydrocarbons without increasing the temperature of EGR gas within the substantially non-oxidizing catalyst unit.

6. A system according to claim 1 wherein the substantially non-oxidizing catalyst unit is operable to catalyze a reaction of hydrocarbons while increasing the temperature of EGR gas within the substantially non-oxidizing catalyst unit by less than about 10 degrees centigrade.

7. A system according to claim 1 further comprising an internal combustion engine and an exhaust manifold, the exhaust manifold being in fluid communication with the intake of the substantially non-oxidizing catalyst unit.

8. A system comprising:

an engine;

an EGR conduit flow coupled to the engine to receive exhaust gas therefrom;

means for reducing molecular weight of hydrocarbon molecules in exhaust gas flow coupled to the EGR conduit; and

means for cooling the EGR flow coupled to the means for reducing molecular weight of hydrocarbon molecules in exhaust gas.

9. A system according to claim 8 wherein the means for cooling the EGR includes an engine coolant cooled EGR cooler.

10. A system according to claim 8 wherein the means for reducing molecular weight of hydrocarbon molecules in exhaust gas includes a zeolite catalyst

11. A system according to claim 8 wherein the means for reducing molecular weight of hydrocarbon molecules in exhaust gas includes a hydrocarbon cracking catalyst.

12. A system according to claim 8 wherein the means for reducing molecular weight of hydrocarbon molecules in exhaust gas includes a solid acid catalyst.

13. A system according to claim 8 wherein the engine is a diesel engine.

14. A system according to claim 8 further comprising a vehicle wherein the diesel engine is configured to be the prime mover of the vehicle.

15. A method comprising:

operating an internal combustion engine to produce exhaust including one or more hydrocarbon compounds;

treating a portion of the exhaust with a substantially non-oxidizing catalyst effective to reduce the molecular weight of the one or more hydrocarbon compounds;

cooling the portion of the exhaust; and

providing the portion of the exhaust to an intake of the internal combustion engine.

16. A method according to claim 15 wherein the treating a portion of the exhaust with a substantially non-oxidizing catalyst effective to reduce the molecular weight of the one or more hydrocarbon compounds includes a hydrocarbon cracking reaction.

17. A method according to claim 15 wherein the treating a portion of the exhaust with a substantially non-oxidizing catalyst effective to reduce the molecular weight of the one or more hydrocarbon compounds includes exposing the one or more hydrocarbon compounds to a hydrocarbon cracking catalyst.

18. A method according to claim 15 wherein the treating a portion of the exhaust with a substantially non-oxidizing catalyst effective to reduce the molecular weight of the one or more hydrocarbon compounds includes exposing the one or more hydrocarbon compounds to a solid acid catalyst.

19. A method according to claim 15 wherein the treating a portion of the exhaust with a substantially non-oxidizing catalyst effective to reduce the molecular weight of the one or more hydrocarbon compounds includes exposing the one or more hydrocarbon compounds to a zeolite catalyst.

20. A method according to claim 15 wherein the treating a portion of the exhaust with a substantially non-oxidizing catalyst occurs in a single catalyst unit positioned upstream from an EGR cooler.