| 摘要 |
PROBLEM TO BE SOLVED: To execute abnormality diagnosis of an air-fuel ratio sensor with enhanced accuracy, and enhance determination accuracy of the air-fuel ratio sensor in consideration of a deterioration state of a catalyst and of an operating state of an internal combustion engine. SOLUTION: An abnormality diagnostic device of an air-fuel ratio sensor contains a measuring means for measuring a flow rate, sets a determination threshold value for determining abnormalities of the air-fuel ratio sensor and determination period for giving proper time to employ a threshold value, calculates a catalyst deterioration index by executing deterioration monitor of a catalyst when performing abnormality diagnosis of the air-fuel sensor, sets determination threshold value and determination period containing catalyst deterioration correction on the basis of the catalyst deterioration index, and determines the abnormality diagnosis of the air-fuel ratio sensor on the basis of a comparison of the determination threshold value and calculated value based on output of an oxygen sensor and a comparison of the determination period and a integrated value of a flow rate calculated based on the measurement of the measuring means. COPYRIGHT: (C)2011,JPO&INPIT
|
