Patent ID: 7143578
Filing Date: 2006-12-05
Classification: B01D,F01N,Y02A,Y02C,Y02T

Abstract:
1. A method for reducing NOx emissions produced by vehicles powered by light duty diesel and similar engines having exhaust gas operating temperatures as low as about 200° C. comprising the steps of: a) increasing the NO b) metering an ammonia reductant into said exhaust gases after said exhaust gases have exited said catalyzed soot filter; and, c) directly passing said exhaust gases with said reductant through an SCR catalyst for reducing said NOx, said SCR catalyst having a set temperature at which said SCR catalyst becomes catalytically active for a set space velocity if said exhaust gases pass through said SCR catalyst with a set quantity of reductant immediately upon exit from said engine that is higher than the temperature at which said SCR catalyst becomes catalytically active when said exhaust gases pass through said SCR catalyst at said set space velocity with said set quantity of reductant after passing through said soot filter.