| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problem of having a risk of temporarily causing the deterioration in exhaust gas and reduction in drivability, for forcibly vibrating the air-fuel ratio when diagnosing the deterioration, due to inevitably reducing a chance of a diagnosis, since a conventional diagnosis of the catalytic deterioration is performed only in a specific operation state. <P>SOLUTION: A catalytic deterioration degree is diagnosed by referring to time series of VFF calculated at any time in its identification process, while identifying a model parameter of a system including a catalyst at any time by a minimum square method using a variable oblivion element on the basis of respective output signals of an upstream side O<SB>2</SB>sensor and a downstream side O<SB>2</SB>sensor arranged on the upstream side and the downstream side of the catalyst. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
