IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0309936
(2002-12-03)
|
발명자
/ 주소 |
- Betta,Ralph Dalla
- Cizeron,Joel
|
출원인 / 주소 |
- Catalytica Energy Systems, Inc.
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
55 인용 특허 :
38 |
초록
▼
The present invention provides systems and methods to improve the performance and emission control of internal combustion engines equipped with nitrogen oxides storage-reduction ("NSR") emission control systems. The system generally includes a NSR catalyst, a fuel processor located upstream of the N
The present invention provides systems and methods to improve the performance and emission control of internal combustion engines equipped with nitrogen oxides storage-reduction ("NSR") emission control systems. The system generally includes a NSR catalyst, a fuel processor located upstream of the NSR catalyst, and at least one fuel injection port. The fuel processor converts a fuel into a reducing gas mixture comprising CO and H2. The reducing gas mixture is then fed into the NSR catalyst, where it regenerates the NSR adsorbent, reduces the NOx to nitrogen, and optionally periodically desulfates the NSR catalyst. The fuel processor generally includes one or more catalysts, which facilitate reactions such as combustion, partial oxidation, and/or reforming and help consume excess oxygen present in an engine exhaust stream. The methods of the present invention provide for NSR catalyst adsorbent regeneration. Control strategies are provided to control the system and methods of the invention.
대표청구항
▼
What we claim is: 1. A method of regenerating a NSR catalyst adsorbent comprising the steps of: injecting fuel into an exhaust stream upstream of a fuel processor, wherein the fuel processor comprises an inlet, an outlet, and at least one catalyst, and the exhaust stream comprises air, whereby the
What we claim is: 1. A method of regenerating a NSR catalyst adsorbent comprising the steps of: injecting fuel into an exhaust stream upstream of a fuel processor, wherein the fuel processor comprises an inlet, an outlet, and at least one catalyst, and the exhaust stream comprises air, whereby the injection of fuel makes the exhaust stream overall lean and rapidly increases the temperature of at least a portion of the fuel processor within the range of about 500° C. to about 750° C.; optionally mixing the exhaust stream with the injected fuel; adjusting the exhaust oxygen concentration or the fuel injection rate to make the exhaust stream overall rich; allowing the fuel and exhaust stream mixture to react within the at least one fuel processor catalyst to generate a reducing gas mixture comprising CO and H2; introducing the reducing gas mixture into a NSR catalyst having an adsorbent, whereby the adsorbent is regenerated by introduction of the reducing gas mixture, and whereby when the amount of reducing gas mixture required to regenerate the adsorbent to a desired level is produced, the injection of fuel is stopped and the fuel processor cools down. 2. The method of claim 1 wherein the exhaust stream is selected from the group consisting of compression ignition engine exhaust and lean bum spark ignited engine exhaust. 3. The method of claim 1 wherein the fuel is vaporized prior to injection. 4. The method of claim 1 wherein the time required to raise the temperature of at least a portion of the catalyst is less than 10 seconds. 5. The method of claim 1 wherein the oxygen concentration in the exhaust stream is less than 6%. 6. The method of claim 1 wherein the step of introducing the reducing gas mixture into the NSR catalyst further facilitates periodic desulfation of the NSR catalyst adsorbent. 7. The method of claim 1 further comprising the use of a control system. 8. The method of claim 1 wherein the fuel processor comprises at least two catalysts, at least one catalyst being a reforming catalyst and at least one catalyst being an oxidation catalyst. 9. The method of claim 1 wherein the fuel is injected intermittently. 10. The method of claim 1 wherein the fuel comprises hydrocarbons. 11. The method of claim 10 wherein the fuel is selected from the group consisting of gasoline and diesel fuel. 12. The method of claim 1 wherein the fuel is injected at an equivalence ratio greater than 1. 13. The method of claim 12 wherein the fuel is injected into the fuel injection port at an equivalence ratio from about 2 to about 5. 14. The method of claim 1 wherein the NSR catalyst is regenerated by operating the fuel processor at an equivalence ratio from about 1.2 to about 7. 15. The method of claim 14 wherein the NSR catalyst is regenerated by operating the fuel processor at an equivalence ratio from about 2 to about 5. 16. A method of controlling the method of claim 1, comprising the steps of: initiating the injection of fuel, whereby the injection of fuel rapidly increases the temperature of at least a portion of the fuel processor within the range of about 500° C. to about 750° C.; reducing the engine exhaust stream oxygen concentration; adjusting the fuel flow rate; maintaining the fuel flow rate until the NSR catalyst adsorbent is regenerated; and terminating the fuel flow. 17. The method of claim 16 wherein the step of initiating the injection of fuel and the step of reducing the engine exhaust stream oxygen concentration occur simultaneously. 18. A method of controlling the method of claim 1 wherein the initiation of fuel injection is dependent upon the measurement of a variable selected from the group consisting of temperature at a desired location within the exhaust stream, oxygen concentration at a desired location within the exhaust stream, NOx concentration at a desired location within the exhaust stream, total exhaust flow rate, and an engine operating parameter. 19. The method of claim 18 wherein the engine operating parameter is further selected from the group consisting of rpm, torque, turbocharger boost, EGR valve setting, and engine air flow. 20. A method of controlling the method of claim 1 by estimating the NOx saturation level of the NSR catalyst. 21. The method of claim 20 wherein the level of saturation is estimated using a NOx sensor downstream of the NSR catalyst. 22. The method of claim 20 wherein the level of saturation is estimated using engine operating parameters that estimate the total amount of NOx produced by the engine. 23. The method of claim 20 wherein the method of claim 1 is initiated when the NSR catalyst is estimated to be at a predetermined level of saturation. 24. A system for reducing NOx in an exhaust stream containing excess O2 comprising: a NSR catalyst; a fuel processor configured to be rapidly heated under lean conditions and operated to reform at least a portion of hydrocarbon fuel under overall rich conditions, the fuel processor located at a position upstream of the NSR catalyst, comprising an inlet, an outlet, and at least one catalyst, wherein the at least one catalyst of the fuel processor comprises a monolithic structure having a wall thickness of 130 microns or less, wherein the monolithic structure comprises an oxidation catalyst and a reforming catalyst; and at least one fuel injection port located upstream of the fuel processor. 25. The system of claim 24 further comprising a fuel preheater, wherein the fuel preheater is located at a position upstream of the fuel processor and downstream of the fuel injection port. 26. The system of claim 24 further comprising a fuel vaporizer, wherein the fuel vaporizer is located at a position upstream of the fuel processor and downstream of the fuel injection port. 27. The system of claim 24 wherein the monolithic structure is constructed from a material selected from the group consisting of ceramic and metal. 28. The system of claim 24 wherein the at least two catalysts are in series. 29. The system of claim 24 wherein the at least two catalysts are in parallel. 30. The system of claim 24 wherein the NSR catalyst and the fuel processor are not located within a single housing structure. 31. The system of claim 24 wherein the NSR catalyst and the fuel processor are located within a single housing structure. 32. A method of controlling the system of claim 24, comprising the steps of: initiating fuel flow into the fuel processor, initiating injection of fuel into a position upstream of the fuel processor, whereby the injection of fuel rapidly increases the temperature of at least a portion of the fuel processor within the range of about 500° C. to about 750° C.; adjusting the fuel flow rate; maintaining the fuel flow rate until the NSR catalyst is regenerated; and terminating the fuel flow. 33. The system of claim 24 further comprising a length of pipe, wherein the pipe is located at a position upstream of the fuel processor and downstream of the fuel injection port. 34. The system of claim 33 wherein the length of pipe is coated with a catalyst adapted for catalyzing the oxidation of varnish or carbonaceous deposits. 35. The system of claim 24 further comprising a control system. 36. The system of claim 35 wherein the control system measures and regulates the fuel flow rate. 37. The system of claim 24 further comprising a thermal mass having a heat capacity greater than that of the fuel processor. 38. The system of claim 37 wherein at least a portion of the thermal mass is selected from the group consisting of a PM filter, the fuel processor, the NSR catalyst, a monolithic structure having a heat capacity greater than that of the fuel processor, and combinations thereof. 39. The system of claim 38 wherein at least a portion of the thermal mass is a PM filter and at least a portion of the thermal mass is a monolithic structure having a heat capacity greater than that of the fuel processor. 40. The system of claim 24 wherein the oxidation catalyst comprises elements selected from the group consisting of Groups VI, VII, VII, and IB of the periodic table of the elements, and combinations thereof. 41. The system of claim 40 wherein the oxidation catalyst comprises elements selected from the group consisting of Pd, Pt, Ir, Rh, Cu, Co, Fe, Ni, Cr, Mo, and combinations thereof. 42. The system of claim 40 wherein the reforming catalyst comprises elements selected from the group consisting of Ni, Rh, Pd, Pt, and combinations thereof. 43. The system of claim 24 further comprising a mixer, wherein the mixer is located at a position upstream of the fuel processor and downstream of the fuel injection port. 44. The system of claim 43 wherein the mixer is a static mixer. 45. The system of claim 43 wherein the mixer comprises a length of pipe, wherein the length of pipe has a L/D ratio greater than 5. 46. The system of claim 43 wherein at least a portion of the mixer is coated with a catalyst adapted for catalyzing the oxidation of varnish or carbonaceous deposits. 47. A fuel processor unit for use with an engine exhaust stream comprising: an inlet for receiving an engine exhaust stream comprising oxygen; an outlet; at least one catalyst, wherein the catalyst comprises a monolithic structure having a wall thickness of 130 microns or less; and at least one fuel injection port, wherein the fuel processor is configured to be rapidly heated under lean conditions and operated to reform at least a portion of hydrocarbon fuel under overall rich conditions. 48. The fuel processor unit of claim 47 wherein at least a portion of the catalyst is heated to at least 500° C. 49. The fuel processor unit of claim 47 further comprising a mixer, wherein the mixer is located downstream of the fuel injection port and upstream of the catalyst. 50. The fuel processor unit of claim 49 wherein the mixer is selected from the group consisting of a static mixer and a length of pipe. 51. The fuel processor unit of claim 47 further comprising at least two catalysts, wherein at least one catalyst is a reforming catalyst and at least one catalyst is an oxidation catalyst. 52. The fuel processor of claim 51 wherein the at least two catalysts are in series. 53. The fuel processor of claim 51 wherein the at least two catalysts are in parallel. 54. The fuel processor unit of claim 51 wherein the oxidation catalyst comprises elements selected from the group consisting of Groups VI, VII, VII and IB of the periodic table of the elements, and combinations thereof. 55. The fuel processor of claim 54 wherein the oxidation catalyst comprises elements selected from the group consisting of Pd, Pt, Ir, Rh, Cu, Co, Fe, Ni, Cr, Mo, and combinations thereof. 56. The fuel processor of claim 54 wherein the reforming catalyst comprises elements selected from the group consisting of Ni, Rh, Pd, Pt, and combinations thereof.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.