초록 ▼

A method for remediating an emission containing NOx emissions includes introducing an exotherm generating agent into the NOx emissions when the inlet temperature of the NOx emissions is in a range of 300° C. to 600° C. and an air/fuel ratio is greater than or equal to 15; exposing the NOx

A method for remediating an emission containing NOx emissions includes introducing an exotherm generating agent into the NOx emissions when the inlet temperature of the NOx emissions is in a range of 300° C. to 600° C. and an air/fuel ratio is greater than or equal to 15; exposing the NOx emissions to a lean NOx trap; introducing a reducing agent into the emissions when the inlet temperature of the emissions is greater than 130° C. and less than 600° C.; exposing the NOx emissions having an air/fuel ratio greater than or equal to 15 to a selective catalytic reduction catalyst; and producing a remediated emission having an air/fuel ratio greater than or equal to 15.

대표청구항 ▼

What is claimed: 1. A method of remediating emissions comprising: exposing a stream of NOx emission from the combustion of an air/fuel mixture having an air/fuel ratio ≧15 to a first lean NOx trap; introducing an exotherm generating agent to the stream downstream of the first LNT; exposing t

What is claimed: 1. A method of remediating emissions comprising: exposing a stream of NOx emission from the combustion of an air/fuel mixture having an air/fuel ratio ≧15 to a first lean NOx trap; introducing an exotherm generating agent to the stream downstream of the first LNT; exposing the stream to a second LNT including adsorbed NOx; introducing a reducing agent to the stream downstream of the second LNT; and exposing the stream to an SCR catalyst. 2. A method for remediating an emission containing NOx emissions using a selective catalytic reduction catalyst and lean NOx traps, the method comprising: (a) exposing a stream of emissions resulting from the combustion of an air/fuel mixture having an air/fuel ratio of greater than or equal to 15 to a first lean NOx trap; (b) introducing an exotherm generating agent to the emission stream downstream of the first LNT; (c) exposing the emission stream to a second LNT including adsorbed NOx; (d) introducing a reducing agent to the emission stream downstream of the second LNT; (e) exposing the emission stream to a first SCR; and (f) producing a remediated emission. 3. The method of claim 2, further comprising ceasing introduction of the exotherm generating agent when the emissions inlet temperature is less than 400° C. 4. The method of claim 2, further comprising introduction of a NOx-free emission to the second LNT during the fourth time segment. 5. The method of claim 2, further comprising introducing the reducing agent at a low emission temperature reducing agent port when the emissions inlet temperature is less than 400° C. 6. The method of claim 5, wherein introducing the reducing agent occurs substantially continuously. 7. The method of claim 2, further comprising: (g) using a valve to direct the emission stream to the first LNT; (h) initiating a remediation sequence; (i) waiting a first switching period; (j) using the valve to direct the emission stream to the second LNT; (k) initiating the remediation sequence; and (l) waiting a second switching period. 8. The method of claim 7, wherein the second switching period is sufficient to purge effective amounts of NOx from the first LNT. 9. The method of claim 7, wherein the second switching period is about 10-300 seconds. 10. The method of claim 7, wherein the second switching period is about 50-70 seconds. 11. The method of claim 7, wherein the valve is a four-way valve. 12. The method of claim 7, wherein initiating the remediation sequence further comprises: (m) introducing the reducing agent during a first time segment; (n) introducing the exothermic generating agent and the reducing agent during a second time segment; (o) introducing the reducing agent during a third time segment; and (p) waiting during a fourth time segment. 13. The method of claim 12, wherein the first time segment is about 5-10 seconds. 14. The method of claim 12, wherein the second time segment is about 5-10 seconds. 15. The method of claim 12, wherein the third time segment is about 5-15 seconds. 16. The method of claim 12, wherein the fourth time segment is about 25-40 seconds.