| 摘要 |
PURPOSE:To compensate the deterioration of an O2 sensor by correcting the delay time set on switching between the rich and lean control, when the min. value of the detection signals of the O2 sensor exceeds a prescribed set range during the air fuel ratio feedback control. CONSTITUTION:When an engine is in revolution, the fundamental fuel amount obtained in a controller 50 according to the outputs of an air flow meter 15 and a revolution speed sensor 29 is corrected on the basis of the outputs of an inhaled air temperature sensor 58, water temperature sensor 59, and an O2 sensor 60, and a fuel injection valve 20 is controlled according to the fuel amount after correction. Further, the detection signal of the O2 sensor 60 is compared with a standard value, and air fuel ratio is switched to the lean or rich control according to the result of the comparison, and said switching is carried-out with a certain delay time. The above-described delay time is corrected when the min. value of the detection signal of the O2 sensor 60 in the air fuel ratio feedback control exceeds a prescribed set range.
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