Patent ID: 7305820

Claim:
An exhaust gas control apparatus for an internal combustion engine, comprising: a NOx storage/reduction catalyst provided in an exhaust passage and which stores NOx in exhaust gas by at least one of adsorption and absorption when an air-fuel ratio of in-flowing exhaust gas is lean, and then reduces and purifies the stored NOx using reduction components in the exhaust gas when the air-fuel ratio of the in-flowing exhaust gas is rich, wherein: an upstream side portion of a carrier of the NOx storage/reduction catalyst, is positioned on an upstream side of an exhaust gas flow, and a downstream side portion of the carrier of the NOx storage/reduction catalyst, is positioned on the downstream side of the exhaust gas flow; the carrier carries an oxygen storage component that absorbs oxygen in the exhaust gas when the air-fuel ratio of the exhaust gas is lean and releases the absorbed oxygen when the air-fuel ratio of the exhaust gas is rich; the amount of the oxygen storage component on the upstream side portion of the carrier is made less than the amount of the oxygen storage component on the downstream side portion of the carrier; and a NOx storage capacity of the upstream side portion of the carrier is made greater than the NOx storage capacity of the downstream side portion of the carrier.