| 摘要 |
PURPOSE:To prevent fluctuation of a feedback control factor due to failure in ignition, noise for stabilization, by a method wherein, in device which feedback-controls an air-fuel ratio, when a change in an output from an air-fuel ratio sensor exceeds a given value, the differential component of a feedback control factor is corrected to a low value. CONSTITUTION:An air-fuel ratio feedback control factor computing means 9 compares an output Vr from a reference value computing means 8, computing a reference value based on the detecting value of an operating state detecting means 7, with a detecting signal Vs from an air-fuel ratio sensor 13 located in an exhaust gas passage 12. A differential component correcting means 10 is connected to the air-fuel ratio feedback control factor computing means 9, and when the degree of a change in a deviation signal provided resulting from comparison of the reference value Vr with the detecting signal Vs from an O2 sensor exceeds a set value, it is decided to be caused by failure in ignition, noise, a differential component in computation of an air-fuel ratio feedback control factor is corrected to a low value by the differential component correcting means 10.
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