Exhaust purification device of compression ignition type internal combustion engine

摘要

An SO_x trap catalyst ( 11 ) able to trap SO_x contained in exhaust gas is arranged in an engine exhaust passage upstream of an NO_x storing catalyst ( 12 ). When the SO_x trap rate by the SO_x trap catalyst ( 11 ) falls, the air-fuel ratio of the exhaust gas flowing into the SO_x trap catalyst ( 11 ) is maintained lean and in that state the SO_x trap catalyst ( 11 ) is raised in temperature. The SO_x trapped at that time diffuses inside the SO_x trap catalyst ( 11 ), whereby the SO_x trap rate is restored.