| 摘要 |
PROBLEM TO BE SOLVED: To provide a degradation diagnosing device capable of preventing from emission degradation during diagnosis as much as possible and to promptly carry out accurate degradation detection. SOLUTION: A disturbance is forcibly outputted without changing a target air-fuel ratio, and a dead time L and a time constantτof the linear air-fuel ratio sensor are calculated as a "dead time + first-order time-lag" from a detected value. At the point of finishing calculation of the dead time L, generation of the disturbance is reset. In calculation of the time constantτ, by using detection of the dead time L as a starting point, the time constantτis calculated within a preset time constant calculation period T<SB>dam</SB>. COPYRIGHT: (C)2007,JPO&INPIT
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