Emissions treatment system with lean NOx trap

摘要

Systems and methods for abating NOx in an exhaust stream are provided. System using a lean NOx trap, an air injector and optional catalysts and filters are described. The emissions treatment system is advantageously used for the treatment of exhaust streams from diesel engines and lean burn gasoline engines.

主权项

1. An emissions treatment system for NOx abatement in a diesel exhaust stream from a diesel engine, comprising:
a lean NOx trap (LNT) located downstream of the engine; an air injector to reduce hydrocarbons located downstream of the NOx trap; and a selective catalytic reduction (SCR) catalyst located downstream of the air injector, wherein when the diesel engine is operated in a rich mode, HC and CO and NH3 generated over the LNT exit the LNT, the NH3 is used to reduce NOx over the SCR catalyst and the HC and CO emitted during the rich mode are oxidized by the injected air.