| 摘要 |
<p>PURPOSE: To judge the abnormally degraded state of a catalyst regardless of the operating state of an engine without changing an air-fuel ratio intentionally by comparing the measured catalyst temperature and the estimated catalyst temperature to judge the abnormally degraded state of the catalyst. CONSTITUTION: On the basis of the input of a catalyst temperature sensor 3, an airflow meter 11, a rotation sensor 12, a water temperature sensor 13, an outside air temperature sensor 14, and the like, the present catalyst temperature in a catalytic converter 1 is measured, and the catalyst temperature at the time of the catalytic converter 1 being in the specified degraded degree of a catalyst is estimated on the basis of the present engine operating state and the external environment of the catalytic converter 1. The measured catalyst temperature and the estimated catalyst temperature are compared to judge the abnormally degraded state of the catalyst in the catalytic converter 1, that is, the evaluation value is determined according to the difference between the measured catalyst temperature and the estimated catalyst temperature, and when the integrated value of the evaluation value is the specified value or more, the catalytic converter 1 is judged to be in the abnormally degraded state of the catalyst.</p> |
