DEGRADATION DIAGNOSING DEVICE FOR LINEAR AIR-FUEL RATIO SENSOR

摘要

PROBLEM TO BE SOLVED: To minimize emission degradation during diagnosis, 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. In the calculation, a time constant time-lag amountτdyis detected beforehand, and on the basis of the time constant time-lag amountτdy, the calculated dead time Lpreis corrected. On the other hand, at the point of finishing calculation of the dead time Lpre, generation of the disturbance is reset. COPYRIGHT: (C)2007,JPO&INPIT