| 摘要 |
A catalyst deterioration detector not causing false detection of catalyst deterioration by eliminating the influence of a variation of the state of the gas at the catalyst outlet on the oxygen storage amount. Setting the lean target A/F to afL1 and the rich target A/F to afR1, the maximum oxygen storage amount Cmax1 is calculated (step 106). Next, setting the lean target A/F to afL2 and the rich target A/F to afR2, the maximum oxygen storage amount Cmax2 is calculated (step 108). Lastly, setting the lean target A/F to afL3 and the rich target A/F to afR3, the maximum oxygen storage amount Cmax3 is calculated (step 110). If these all calculated maximum oxygen storage amounts Cmax1, Cmax2, Cmax3 are less than a reference value Cmaxth, catalyst deterioration is detected (step 116).
|
