EXHAUST GAS PURIFICATION DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

In order to maintain the NOx purification performance of the entire exhaust gas purification device regardless of the deterioration of an NOx storage reduction catalyst when an NOx selective reduction catalyst is provided downstream from the NOx storage reduction catalyst, the reduction of NOx in the NOx storage reduction catalyst is promoted further when the degree of deterioration of the NOx storage reduction catalyst or the NOx selective reduction catalyst is low than when high, and the reduction of NOx in the NOx selective reduction catalyst is promoted further when the degree of deterioration of the NOx storage reduction catalyst or the NOx selective reduction catalyst is high than when low.