Exhaust gas treatment system including an HC-SCR and two-way catalyst and method of using the same
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F01N-003/00
F01N-003/021
F01N-003/20
출원번호
US-0486017
(2009-06-17)
등록번호
US-8904760
(2014-12-09)
발명자
/ 주소
Mital, Rahul
출원인 / 주소
GM Global Technology Operations LLC
대리인 / 주소
Cantor Colburn LLP
인용정보
피인용 횟수 :
12인용 특허 :
9
초록▼
An exhaust gas treatment system for a diesel engine is disclosed. The exhaust gas treatment system includes a hydrocarbon selective catalytic reduction catalyst (HC-SCR) in fluid communication with a diesel engine to receive an exhaust gas flow therefrom. The system also includes a two-way catalyst
An exhaust gas treatment system for a diesel engine is disclosed. The exhaust gas treatment system includes a hydrocarbon selective catalytic reduction catalyst (HC-SCR) in fluid communication with a diesel engine to receive an exhaust gas flow therefrom. The system also includes a two-way catalyst in fluid communication with the HC-SCR to receive the exhaust gas flow therefrom, the two-way catalyst comprising a urea selective catalytic reduction catalyst and a diesel particulate filter (DPF).
대표청구항▼
1. An exhaust gas treatment system for a diesel engine, comprising: a diesel oxidation catalyst in fluid communication with a diesel engine to receive an exhaust gas flow therefrom;a hydrocarbon selective catalytic reduction catalyst (HC-SCR) in direct fluid communication with the diesel oxidation c
1. An exhaust gas treatment system for a diesel engine, comprising: a diesel oxidation catalyst in fluid communication with a diesel engine to receive an exhaust gas flow therefrom;a hydrocarbon selective catalytic reduction catalyst (HC-SCR) in direct fluid communication with the diesel oxidation catalyst through a first conduit that extends directly from the diesel oxidation catalyst to the HC-SCR to receive the exhaust gas flow therefrom;a two-way catalyst in direct fluid communication with the HC-SCR through a second conduit that extends directly from the HC-SCR to the two-way catalyst to receive the exhaust gas flow therefrom, the two-way catalyst comprising a urea selective catalytic reduction (two-way) catalyst and a diesel particulate filter (DPF);a first injection device that is configured to inject a hydrocarbon, CO or H2 material, or a combination thereof, into the exhaust gas flow between the engine and the diesel oxidation catalyst, wherein the diesel oxidation catalyst, HC-SCR and two-way catalyst are the only catalyst devices used in the exhaust gas treatment system;a second injection device that is configured to inject urea or ammonia, or a combination thereof, into the exhaust gas flow between the HC-SCR and the two-way catalyst; and a controller configured to periodically reduce the reliance on the HC-SCR by the use of the two-way catalyst to balance NOx conversion load of the exhaust gas treatment system. 2. The exhaust gas treatment system of claim 1, wherein the HC-SCR catalyst comprises a ceramic flow-through monolith and the two-way catalyst comprises a ceramic wall-flow monolith. 3. The exhaust gas treatment system of claim 2, wherein the HC-SCR catalyst comprises a first washcoat disposed on the ceramic flow-through monolith, the first washcoat comprising platinum disposed on a ceramic matrix or Cu or Ag, or a combination thereof, disposed on a zeolite matrix and the U-SCR catalyst comprises a second washcoat disposed on the ceramic wall-flow monolith, the second washcoat comprising copper or iron, or a combination thereof, disposed on a zeolite matrix. 4. The exhaust gas treatment system of claim 2, wherein the two-way catalyst comprises a washcoat disposed on the ceramic wall-flow monolith, the washcoat comprising vanadia. 5. The exhaust gas treatment system of claim 2, wherein the two-way catalyst comprises a first two-way catalyst and a second two-way catalyst, the second two-way catalyst comprising a washcoat disposed on a second ceramic or metal flow-through monolith. 6. The exhaust gas treatment system of claim 5, wherein the second flow-through monolith is disposed to receive the exhaust gas flow prior to or after the wall-flow monolith. 7. The exhaust gas treatment system of claim 1, wherein the two-way catalyst comprises a plurality of ceramic wall-flow monoliths. 8. The exhaust gas treatment system of claim 1, wherein the exhaust gas flow from the engine has a first volume fraction of NOx (NOx1) and the exhaust gas flow exiting the two-way catalyst has a second volume fraction of NOx (NOx2), and wherein NO2x≦0.1 NOx1. 9. A method of using an exhaust treatment system comprising a diesel oxidation catalyst in fluid communication with a diesel engine to receive an exhaust gas flow therefrom; a hydrocarbon selective catalytic reduction catalyst (HC-SCR) in direct fluid communication with the diesel oxidation catalyst through a first conduit that extends directly from the diesel oxidation catalyst to the HC-SCR to receive an exhaust gas flow therefrom; a two-way catalyst in direct fluid communication with the HC-SCR through a second conduit that extends directly from the HC-SCR to the two-way catalyst to receive the exhaust gas flow therefrom; a first injection device that is configured to periodically and selectively inject a hydrocarbon, CO or H2 material, or combination thereof, into the exhaust gas flow between the diesel oxidation catalyst and the engine; a second injection device that is configured to periodically and selectively inject urea or ammonia, or a combination thereof, into the exhaust gas flow between the HC-SCR and the two-way catalyst; and a controller that is configured to control operation of the engine and periodic and selective injection of the hydrocarbon, CO or H2 material, or combination thereof, and periodic and selective injection of the urea or ammonia, or combination thereof, and determine an amount of NOx in the exhaust gas flow, wherein the diesel oxidation catalyst, HC-SCR and two-way catalyst are the only catalyst devices used in the exhaust gas treatment system; comprising: operating the engine to produce the exhaust gas flow;periodically and selectively injecting the hydrocarbon, CO or H2 material, or a combination thereof, and the urea or ammonia, or a combination thereof, into the exhaust gas flow using the controller, wherein the exhaust gas flow from the engine has a first volume fraction of NOx (NOx1) and the exhaust gas flow exiting the two-way catalyst has a predetermined second volume fraction of NOx (NOx2); andperiodically reducing using the controller, the reliance on the HC-SCR by using the two-way catalyst to balance an NOx conversion load of the exhaust treatment system. 10. The method of claim 9, wherein periodically and selectively injecting comprises injecting the hydrocarbon, CO or H2 material, or combination thereof, into the exhaust gas flow. 11. The method of claim 10, wherein the HC-SCR provides a volume fraction reduction of NOx1 expressed as a third volume fraction of NOx1 (NOx3) in the exhaust gas flow exiting the HC-SCR catalyst, wherein 0.50 NOx1≦NOx3≦0.80 NOx1. 12. The method of claim 11, wherein the controller is configured to operate in a first mode to minimize consumption of urea or ammonia, or a combination thereof, and minimize NO3. 13. The method of claim 9, wherein periodically and selectively injecting comprises injecting the urea or ammonia, or a combination thereof, into the exhaust gas flow. 14. The method of claim 13, wherein the two-way catalyst provides a volume fraction reduction of NOx1 expressed as a fourth volume fraction of NOx1 (NOx4), wherein 0.05 NOx1≦NOx4≦0.60 NOx1. 15. The method of claim 14, wherein the controller is configured to operate in a second mode to minimize consumption of hydrocarbon, CO or H2 material, or combination thereof, and minimize NOx4. 16. The method of claim 9, wherein the controller is configured to control the exhaust gas flow from the engine, the first injection device or the second injection device, or a combination thereof, to produce a predetermined second volume fraction of NOx2≦0.10 NOx1. 17. A diesel engine and exhaust gas treatment system, comprising: a diesel engine;a diesel oxidation catalyst in fluid communication with the diesel engine to receive an exhaust gas flow therefrom;a hydrocarbon selective catalytic reduction catalyst (HC-SCR) in direct fluid communication with the diesel oxidation catalyst through a first conduit that extends directly from the diesel oxidation catalyst to the HC-SCR to receive the exhaust gas flow therefrom;a two-way catalyst in direct fluid communication with the HC-SCR through a second conduit that extends directly from the HC-SCR to the two-way catalyst to receive the exhaust gas flow therefrom, the two-way catalyst comprising a urea selective catalytic reduction (two-way) catalyst and a diesel particulate filter (DPF);a first injection device that is configured to inject a hydrocarbon, CO or H2 material, or a combination thereof, into the exhaust gas flow between the engine and the diesel oxidation catalyst, wherein the diesel oxidation catalyst, HC-SCR and two-way catalyst are the only catalyst devices used in the exhaust gas treatment system;a second injection device that is configured to inject urea or ammonia, or a combination thereof, into the exhaust gas flow between the HC-SCR and the two-way catalyst; anda controller configured to periodically reduce the reliance on the HC-SCR by the use of the two-way catalyst to balance an NOx conversion load of the exhaust gas treatment system. 18. The system of claim 17, further comprising a second two-way catalyst in direct fluid communication with the HC-SCR through the second conduit to receive the exhaust gas flow therefrom, the second two-way catalyst comprising a second urea selective catalytic reduction (two-way) catalyst and a second diesel particulate filter (DPF). 19. The system of claim 18, wherein the second conduit forms a split exhaust path, wherein the two-way catalyst and the second two-way catalyst are arranged in parallel in the split exhaust path. 20. The system of claim 17, further comprising a first NOx sensor arranged between the diesel engine and the diesel oxidation catalyst, a temperature sensor arranged in the first conduit between the diesel oxidation catalyst and the HC-SCR, and a second NOx sensor arranged downstream of the two-way catalyst.
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이 특허에 인용된 특허 (9)
Fisher, Galen B.; DiMaggio, Craig L.; Rahmoeller, Ken M.; Sellnau, Mark C., Dual catalyst NOx reduction system for exhaust from lean burn internal combustion engines.
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