Patent ID: 8329127

Claim:
A method for generating heat for soot removal and reducing NH3 slip in an exhaust system, said method comprising: injecting nitrogenous reductant into an exhaust flow having NOx; reducing said NOx using said nitrogenous reductant in the presence of an SCR catalyst to form a NOx-reduced gas stream, which, at least intermittently, contains slip nitrogenous reductant; injecting HC into said NOx-reduced gas stream to form a HC-enriched gas stream; contacting said HC-enriched gas stream with a combined catalyst to form a heated gas stream, said combined catalyst comprising a first layer having an oxidization catalyst to oxidize at least a portion of said HC to heat said heated gas stream, and a second layer having an SCR catalyst to reduce at least a portion of NOx in said heated gas stream; and contacting said heated gas stream with a soot filter to regenerate soot in said filter.