Patent ID: 9662611
Date: 2017-05-30
CPC Classifications: B01D,F01N,Y02T

Claim:
1. A emissions treatment system for an exhaust stream of a diesel engine or a lean bum gasoline engine comprising: an in-situ ammonia-generating component; and an SCR catalyst disposed downstream of the ammonia-generating component, wherein the SCR catalyst comprises a molecular sieve having the CHA crystal structure having a mole ratio of silica-to alumina of from about 15 to about 256, wherein the ammonia-generating component comprises a lean NOx trap (LNT) catalytic material disposed on an upstream carrier that is a flow through monolith; where the lean NOx trap (LNT) catalytic material comprises an undercoat washcoat layer and a top washcoat layer, the top washcoat layer exhibiting better low temperature NOx abatement performance than the undercoat washcoat layer.