Exhaust purification device and exhaust purification method of internal combustion engine

Abstract

A NOstoring catalyst () comprising a precious metal catalyst () and NOabsorbent () is arranged in an exhaust passage. When the air-fuel ratio of the exhaust gas is lean, the storing catalyst cold stores the NOcontained in the exhaust in the absorbent when the catalyst is inactive and hot stores the cold stored NOin the absorbent when the catalyst is made active. The NOcontained in the exhaust is cold stored in the absorbent when the catalyst is not activated, and when a predetermined NOstoring catalyst restoring condition () is met, a NOstoring catalyst restoring control () including raising the NOstoring catalyst temperature to a predetermined temperature to active it () is executed so as to restore the cold storing capability of the NOabsorbent.