| 摘要 |
PURPOSE: To correctly detect the damage of the catalyst by the sulphur contents in the fuel by calculating the accumulated value of the product of the fuel supply by the damage factor by the catalyst temperature, and detecting the poisoned condition of the catalyst by the sulphur concentration in the fuel based on the calculated accumulated value. CONSTITUTION: An exhaust emission control device is interposed in an exhaust passage 8 of an engine 1. An electrically heated catalyst EHC 9 controls the elimination of the sulphur concentration by realizing ON/OFF control of an electric heating means. In controlling the elimination of the sulphur concentration, the poisoning is started when the electric heating means is turned OFF, and the poisoning is continued until the prescribed period of time is elapsed. The accumulated value of the product of the fuel injection by the poisoning factor based on the temperature of the EHC 9 is obtained by a poisoning counter, and the sulphur concentration of the fuel is detected by checking the rate of addition when the temperature of the EHC 9 is kept for the prescribed period of time to detect the poisoned amount. The poisoning is preliminarily prevented by realizing the shift control of the air-fuel ratio according to this sulphur concentration. |
