Nitrogen oxides emission control under lean-burn conditions

摘要

A nitrogen oxide trap/catalyst system which provides an NOx reducing catalyst, (LNC) upstream from a lean NOx trap/catalyst (LNT) for use in a lean-burn engine exhaust system. The LNC catalyzes the reduction of NOx compounds through a reaction with hydrocarbons in the exhaust gas at temperatures of 300 {C to 600 {C. Also disclosed is a three-way catalyst (TWC) positioned between a NOx reducing catalyst (LNC) and a lean NOx trap/catalyst (LNT).