초록 ▼

An exhaust system can comprise a NOx adsorber, a reformer disposed upstream of a NOx adsorber and in fluid communication with a fuel source, a first valve for controlling the introduction of the fluid to an exhaust conduit; and a particulate filter disposed upstream and in fluid communication with t

An exhaust system can comprise a NOx adsorber, a reformer disposed upstream of a NOx adsorber and in fluid communication with a fuel source, a first valve for controlling the introduction of the fluid to an exhaust conduit; and a particulate filter disposed upstream and in fluid communication with the NOx adsorber and downstream an in fluid communication with the reformer such that the first valve controls introduction of fluid to the exhaust conduit upstream of the particulate filter. The reformer can be designed to generate a fluid comprising sufficient thermal energy, hydrogen, and carbon monoxide. Optionally, the particulate filter can be designed to be regenerated by the thermal energy and to adsorb a sufficient amount of the thermal energy to reduce the temperature of a gas stream comprising the fluid from a first temperature of about 600째 C. to about 1,000째 C. to a second temperature of less than or equal to about 500째 C.

대표청구항 ▼

What is claimed is: 1. An exhaust system, comprising: an acid/base NOx adsorber; a reformer physically integrated with an exhaust manifold and disposed upstream of the adsorber and in fluid communication with a fuel source, wherein the reformer is designed to generate a fluid comprising thermal ene

What is claimed is: 1. An exhaust system, comprising: an acid/base NOx adsorber; a reformer physically integrated with an exhaust manifold and disposed upstream of the adsorber and in fluid communication with a fuel source, wherein the reformer is designed to generate a fluid comprising thermal energy, hydrogen, and carbon monoxide; a first valve for controlling the introduction of the fluid to an exhaust conduit; and a particulate filter disposed upstream and in fluid communication with the NOx adsorber and downstream and in fluid communication with the reformer such that the first valve controls introduction of fluid to the exhaust conduit upstream of the particulate filter. 2. The system of claim 1, wherein said reformer is a partial oxidation reformer designed to generate the thermal energy such that, when the fluid is combined with a gas stream in the exhaust conduit to form a heated stream, the heated stream has a temperature of about 600째 C. to about 1,000째 C. 3. The system of claim 1, wherein the NOx adsorber comprises a substrate with an acid adsorber underlayer disposed beneath a base adsorber overlayer. 4. The system of claim 3, wherein the acid adsorber underlayer comprises: an acid adsorber zirconium component in solid solution with at least one of an alkali element component and an alkaline earth metal component; and an acid adsorber precious metal component. 5. The system of claim 4, wherein the acid adsorber precious metal component comprises about 90 mol. % to about 99 mol. % platinum and about 1 mol. % to about 10 mol. % rhodium, based on the total moles of the acid adsorber precious metal component. 6. The system of claim 5, wherein the alkali element component and an alkaline earth metal component are selected from the group consisting of comprises barium, strontium, calcium, magnesium, cesium, rubidium, potassium, sodium, lithium, and a combination comprising one or more of the foregoing. 7. The system of claim 3, wherein the base adsorber overlayer comprises: a base adsorber zirconium component in solid solution with an transition metal oxide component; and a base adsorber precious metal component. 8. The system of claim 7, wherein the base adsorber precious metal component comprises about 10 mol. % to about 40 mol. % of platinum and about 60 mol. % to about 90 mol. % of ruthenium, based on the total moles of the base adsorber precious metal component. 9. The system of claim 8, wherein the transition metal oxide is selected from the group consisting of vanadium oxide, niobium oxide, molybdenum oxide, tungsten oxide, rhenium oxide, nickel oxide, and a combination of one or more of the foregoing transition metal oxides. 10. The system of claim 1, further comprising a first oxidation catalyst disposed upstream of the particulate filter and downstream of the reformer, and a second oxidation catalyst disposed downstream of the NOx adsorber. 11. The system of claim 10, wherein the first oxidation catalyst further comprises a first support and a first catalytic metal component and the second oxidation catalyst further comprises a second support and a second catalytic metal component, wherein the first catalytic metal component comprises about 60 at % to about 90 at % platinum and about 10 at % to about 40 at % ruthenium, based upon the total weight of the first catalytic metal component; wherein the second catalytic metal component comprises about 50 at % to about 75 at % platinum and about 50 at % to about 25 at % palladium, based upon the total weight of the second catalytic metal component; and wherein the first support and the second support are, individually, selected from the group consisting of zirconium solid solutions, zirconium titanium oxides, titanium oxides, zirconium oxides, aluminum oxides, zirconium toughened aluminum oxide, titanium toughened aluminum oxide, and combinations comprising at least one of the foregoing supports. 12. The system of claim 11, wherein at least one of the first support and the second support is selected from the group consisting of zirconium titanium solid solution, zirconium titanium aluminum solid solution, and combinations comprising at least one of the foregoing supports. 13. The system of claim 11, further comprising a second valve for controlling the introduction of the fluid to the exhaust conduit upstream of the first oxidation catalyst, and wherein the first valve located to control fluid introduction to the exhaust conduit downstream of the first oxidation catalyst. 14. The system of claim 1, further comprising a computer for controlling the system. 15. The system of claim 1, wherein the reformer comprises a reformer substrate comprising a reformer support and a reformer catalyst; wherein the reformer catalyst comprises about 70 at % to about 85 at % rhodium and about 2.5 at % to about 20 at % platinum based on the total weight of the reformer catalyst; wherein the reformer support is selected from the group consisting of hexaalluminogallates, alluminogallates, hexaaluminates, aluminum oxidetes, zirconium toughened aluminum oxide, titanium toughened aluminum oxide, aluminum oxide, and combinations comprising at least one of the foregoing reformer supports; and wherein the reformer substrate is selected from the group consisting of zirconium toughened aluminum oxide, titanium toughened aluminum oxide, aluminum oxide, zirconium oxide, titanium oxide, as well as oxides, alloys, cermets, and combinations comprising at least one of the foregoing reformer substrates. 16. The system of claim 1, wherein the reformer catalyst comprises about 70 at % to about 80 at % rhodium and about 5 at % to about 10 at % platinum. 17. The system of claim 15, wherein the reformer support is selected from the group consisting of hexaalluminogallates, alluminogallates, hexaaluminates, and combinations comprising at least one of the foregoing reformer supports. 18. The system of claim 1, wherein the particulate filter comprises a wall flow monolithic substrate comprising a filter substrate material selected from the group consisting of silicon carbide and stainless steel. 19. The system of claim 1, further comprising a phosphate trap disposed downstream of the particulate filter and upstream of the NOx adsorber, wherein the phosphate trap consists essentially of a trap material supported on a trap substrate, and wherein the trap material is selected from the group consisting of zeolites, high surface area aluminum oxide, zirconium toughened aluminum oxide, titanium toughened aluminum oxide, and aluminum oxide. 20. The system of claim 19, wherein the trap material is a zeolite. 21. A method for operating an exhaust system, comprising: generating a gas stream comprising NOx and particulate; passing the gas stream through a particulate filter and then through a NOx adsorber, wherein, during a storage phase, the particulate filter removes the particulate from the gas stream and the NOx adsorber adsorbs the NOx on an acid adsorber; regenerating by: generating a fluid comprising thermal energy, hydrogen, and carbon monoxide from a fuel; introducing the fluid to a gas stream to form a heated stream having a temperature of about 600째 C. to about 1,000째 C.; introducing the heated stream to the particulate filter; regenerating the particulate filter; reducing the temperature of the heated stream to form a particulate effluent having a temperature of less than or equal to about 500째 C.; introducing the particulate effluent to a NOx adsorber, wherein the hydrogen reacts with adsorbed NOx to form NHx; adsorbing the NHx on a base adsorber in the NOx adsorber; and forming an adsorber effluent. 22. The method of claim 21, wherein the gas stream has an engine comprises an a/f ratio greater than or equal to 14.7. 23. The method of claim 22, wherein the a/f ratio is about 19 to about 35. 24. The method of claim 21, wherein the heated stream has an a/f ratio of less than or equal to about 13. 25. The method of claim 24, wherein the a/f ratio is about 11. 5 to about 12.5. 26. The method of claim 21, further comprising: introducing the heated fluid to a first oxidation catalyst before introducing the heated fluid to the particulate filter; and wherein the heated fluid has a temperature of about 600째 C. to about 1,000째 C. 27. The method of claim 21, wherein periods of time between regenerating are greater than or equal to 30 minutes, and wherein the regenerating is for a regeneration period of less than or equal to about 2 minutes. 28. The method of claim 21, wherein the heated stream has a temperature of greater than or equal to about 700째 C. when it enters the particulate filter. 29. The method of claim 21, wherein the regenerating further comprises introducing the particulate effluent to a phosphate trap prior to introducing the particulate effluent to the NOx adsorber, and adsorbing vapor phase glass formers in the phosphate trap. 30. The method of claim 21, wherein the particulate effluent entering the NOx adsorber has a temperature of less than or equal to about 600째 C. 31. The method of claim 21, wherein the temperature is about 300째 C. to about 500째 C. 32. The method of claim 21, further comprising reacting NOx in the gas stream with the NHx to form diatomic nitrogen. 33. The method of claim 21, further comprising oxidizing at least one species in the adsorber effluent in a second oxidation catalyst. 34. The method of claim 33, wherein the adsorber effluent entering the second oxidation catalyst has a temperature of about 200째 C. to about 350째 C. 35. The method of claim 21, further comprising selectively controlling introduction of the fluid to the gas stream upstream of a first oxidation catalyst and downstream of the first oxidation catalyst. 36. The method of claim 21, further comprising controlling a duration the storage phase, a duration the regenerating, an amount of the thermal energy generated, and an a/f of the heated stream. 37. The method of claim 21, further comprising depositing a fuel additive on the particulate filter. 38. The method of claim 37, wherein the fuel additive comprises cerium. 39. The method of claim 37, wherein the amount of fuel additive deposited on the particulate filter is about 4 ppm to about 12 ppm, based upon weight. 40. The method of claim 37, further comprising regenerating the fuel additive. 41. A method for operating an exhaust system, comprising: generating a gas stream comprising NOx and particulates; passing the gas stream through a particulate filter, then through a phosphate trap, and then through a NOx adsorber, wherein, during a storage phase, the particulate filter removes the particulates from the gas stream and the NOx adsorber adsorbs the NOx on an acid adsorber; regenerating by: generating a fluid comprising thermal energy, hydrogen, and carbon monoxide from a fuel; introducing the fluid to a gas stream to form a heated stream having a temperature of about 700째 C. to about 1,000째 C.; introducing the heated stream to a first oxidation catalyst; introducing the heated stream to the particulate filter, wherein the heated stream has a temperature of greater than or equal to 700째 C. when it enters the particulate filter, regenerating the particulate filter; reducing the temperature of the heated stream to form a particulate effluent having a temperature of less than or equal to about 700째 C.; introducing the particulate effluent to the phosphate trap; adsorbing vapor phase glass formers in the phosphate trap to form a trap effluent; introducing the trap effluent to the NOx adsorber, wherein the trap effluent has a temperature of about 300째 C. to 500째 C. when entering the NOx adsorber, and wherein the hydrogen reacts with adsorbed NOx to form NHx; adsorbing the NHx on a base adsorber in the NOx adsorber and forming an adsorber effluent; and introducing the adsorber effluent to a second oxidation catalyst, wherein the adsorber effluent has a temperature of about 200째 C. to about 350째 C. when entering the second oxidation catalyst.