Patent ID: 6499294
Filing Date: 2002-12-31
Classification: B01D,F01N,F02D,Y02T

Abstract:
An exhaust gas purification device for an internal combustion engine, comprising an NOx absorbing and reduced catalyst which absorbs NOx in the exhaust gas when the air-fuel ratio of the exhaust gas flowing in is lean and realeases the absorbed NOx and purifies it by reduction when the air-fuel ratio of the exhaust gas flowing in is rich, disposed in an exhaust passage of the interal combustion engine operable at at least one of a lean air-fuel ratio and a rich air-fuel ratio so that the NOx absorbing and reducing catalyst absorbs NOx in the exhaust gas when the engine is operated at a lean air-fuel ratio and that absorbed NOx is released from the NOx absorbing and reduced catalyst and is purified by reduction when the engine is operated at a rich air-fuel ratio;wherein oxygen storage components are carried by a substrate of said NOx absorbing and reducing catalyst solely on the upstream half portion of the substrate from an end surface on the exhaust inlet side up to a central portion thereof, in order to absorbed oxygen when the air-fuel ratio of the exhaust gas is rich.