| 摘要 |
PURPOSE:To enable restoration to the normal state to be quickly detected by prohibiting calculation of a mean value when the mean value of an air-fuel ratio correction factor is changed to the outside of the specific range after abnormality of a fuel supplying system is judged. CONSTITUTION:An air-fuel ratio feedback correction factor KO2 is calculated on the basis of an output voltage of an O2 sensor in the feedback control. Here, when abnormality in a fuel supplying system is judged, the calculating time interval of an integral value (a moderate means value) KAV of the air-fuel ratio correction factor KO2 is so set as to calculate the integral value KAV. After the calculation of the KAV value is performed for the specific time, a parameter KO2AVE for judging abnormality is put in comparison. When the abnormality judging parameter KO2AVE is outside the range of a deterioration judging lower limit value KO2AVEFSL, it is judged that the fuel supplying system is abnormal. Moreover, the KO2AVE value is held to a lower side limit value KO2AVEFSLLMT in the abnormality time. Thereby, when the state is restored to the normal state after abnormalities are judged, the judgement can be immediately performed. |
