EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PURPOSE: To improve exhaust emission by activating both catalyst metals effectively in a catalyst which is carried with both of rhodium or platinum and palladium. CONSTITUTION: An exhaust emission control device is provided with a rich deterioration recovery treatment inhibiting means 104 for inhibiting control by a rich deterioration recovery treatment means 103 when the deterioration degree of a catalyst 101 is larger than a prescribed value after control is carried out by the rich deterioration recovery treatment means 103, and a lean deterioration recovery treatment inhibiting means 106 for inhibiting control by a lean deterioration recovery treatment means 105 when the deterioration degree of the catalyst 101 is larger than a prescribed value after control is carried out by the lean deterioration recovery treatment means 105.