| 摘要 |
PROBLEM TO BE SOLVED: To specify which is deteriorated an HC adsorption part or an oxidization catalyst part when it is determined that exhaust emission control catalyst having integrally the HC adsorption part and the oxidization catalyst part is deteriorated.SOLUTION: There is arranged in an engine exhaust emission passage, an exhaust emission control catalyst having integrally an HC adsorption part in which HC contained in exhaust emission is adsorbed at a temperature lower than HC discharging temperature and the adsorbed HC is discharged at a temperature more than HC discharging temperature, and an oxidization catalyst part in which HC discharged from the HC adsorption part and HC contained in the exhaust emission are oxidized and controlled at a high temperature. Thermal deterioration characteristics of the HC adsorption part and the oxidization catalyst part are different from each other. A thermal load at each of a low temperature region and a high temperature region is calculated and integrated and the integrated thermal load is stored and updated. When it is determined that the exhaust emission control catalyst is deteriorated in response to a heat generated state in the oxidization catalyst part, thermal loads stored for each of the temperature regions are compared with each other, and it is specified which is deteriorated the HC adsorption part or the oxidization catalyst part 41b. |
