| 摘要 |
<p>PURPOSE: To detect deterioration caused by sulfur poisoning of a catalyst which is arranged in the exhaust system of an internal combustion engine independently of deterioration caused by secular change. CONSTITUTION: Output PVO2 and SVO2 of O2 sensors 15, 16 which are arranged upstream and downstream of a catalytic converter rhodium 14 are read in (Step S81, S82), and it is judged on the basis of those sensor outputs whether sulfur poisoning of the three way catalyst 14 is generated or not (Step S83). To say concretely, for example, when the maximum value SVO2MAX of downstream side O2 sensor output SVO2 is in a prescribed value SVO2 REF1 and less, sulfur poisoning is judged.</p> |
