| 摘要 |
PROBLEM TO BE SOLVED: To effectively reduce Ag2O to improve an HC adsorption amount and an HC emission temperature, while keeping an HC adsorption performance in a high temperature. SOLUTION: When it is determined that a deterioration degree of an HC adsorption agent layer is high at a step S8 and the temperature of an adsorption catalyst is high at a step S12, a fuel amount is increased to transit an air-fuel ratio to a rich side. Thereby, the concentration of O2 in exhaust gas is lowered to reduce Ag2O. |
