| 摘要 |
<P>PROBLEM TO BE SOLVED: To increase opportunities of determination of catalyst deterioration utilizing an amount of oxygen to be released after fuel cut is stopped. <P>SOLUTION: An electrical control device calculates an amount of oxygen to be supplied to an upstream side catalyst during fuel cut (amount of oxygen supplied Ckyu) and maintains the air/ fuel ratio of an air fuel mixture to be supplied to an engine after the fuel cut is stopped at a set rich fuel/ air ratio. The electrical control device calculates an amount of oxygen to be released from the upstream side catalyst for a period between after the fuel cut is stopped and until gas having an air/ fuel ratio richer than the theoretical air/ fuel ratio flows to the downstream of the upstream side catalyst (amount of oxygen released Chosytu). Then, from the standpoint that the amount of oxygen released Chosytu, when smaller than the amount of oxygen supplied Ckyu, can be considered to be equal to the maximum oxygen occlusion Cmax, the electrical control device determines the deterioration of the catalyst based on the amount of oxygen released Chosytu when detecting such a case. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
