| 摘要 |
PURPOSE:To prevent the fuel feeding quantity from exceeding a combustion range even if anomaly is generated in an air-fuel ratio sensor by reducing the control width in the air-fuel ratio feedback control as the aimed air-fuel ratio is set to the lean or rich side. CONSTITUTION:An electronic control circuit 9 controls the valve opening time of an injector 6 on the basis of each detection value of a pressure sensor 4 for detecting the intake pipe negative pressure on the downstream side of a throttle valve 3 in an intake pipe, revolution sensor 5 and an air-fuel ratio sensor 8 which can detects the values on the rich and lean sides in comparison with the theoretical air-fuel ratio. The controller 9 sets an aimed air-fuel ratio according to the operation state, and as the aimed air-fuel ratio is set to the lean or rich side in comparison with the theoretical air-fuel ratio, the control width in feedback control is reduced, in comparison with the control width in the case when the aimed air-fuel ratio is equal to the theoretical air-fuel ratio.
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