| 摘要 |
PROBLEM TO BE SOLVED: To keep an oxygen sensor in an activated state even an engine is left idling at a low outside air temperature and to maintain precision of an air-fuel ratio feedback control during idling. SOLUTION: When an outside air temperature is below a given temperature (S2), when an engine is brought into an idle running state S3, an average valueαAV of a current air-fuel ratio feedback correction factorαis stored as a reference valueαS (S4→S5). In a subsequent idle running state, the reference valveαS is compared with a update average valueαAV S6 and when a deviationΔαtherebetween exceeds a given value (S7), non-activation of an oxygen sensor is estimated, and an ignition timing is delayed for correction by an angle of delay correction amountΔADV according to theΔαto increase an exhaust gas temperature (S8, S9).
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