| 摘要 |
PURPOSE:To suppress a change of air-fuel ratio, by transferring target air-fuel ratio to be fixed to the sir-fuel ratio immediately before an operative condition changes when a change rate of the operative condition is in a predetermined value or more, in the case of a control device which performs a feedback control of the air-fuel ratio in accordance with an output from an air-fuel ratio sensor. CONSTITUTION:When an engine is in operation, a control unit 20, fetching an output signal from an air flow meter 21, lean sensor 19 and an accelerator pedal depression sensor 23 or the like, discriminates a zone for a feedback (F/B) on the basis of an engine speed and load (throttle valve opening). When the F/B zone is discriminated, the control unit, comparing an operative condition change rate (accelerator pedal depression change rate) W with the predetermined value W1, performs an ordinary F/B control in a compared relation where W<W1 while stops the F/B control in the relation where W1<W<W2. While the control unit is transferred to a routine, fixing target air-fuel ratio to that immediately before an operative condition changes, in case of the relation where W>W2. Thereafter when the change rate W is reset to the predetermined value W1 or less, the control unit controls said target air-fuel ratio, immediately before the operative condition changes, to be gradually approximated to the present target air-fuel ratio.
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