| 摘要 |
PURPOSE:To make it possible to very accurately control an air fuel ratio by adjusting the amount of fuel supply while properly changing the voltage to be applied to a sensor element part in responce to the target air fuel ratio and comparing the resultant output current from the sensor element part with the current at the target air fuel ratio. CONSTITUTION:A target air fuel ratio is set in a target air fuel ratio operating circuit within a control circuit 20, using the output signals from an air flow meter 24, a distributor 12 and a cooling water temperature sensor 12, and a basic fuel injection amount for an injector 30 is set in a basic fuel injection operating circuit. Said target air fuel ratio is converted into the target oxygen concentration, and thereby a current value (reference current value) corresponding to the target oxygen concentration is determined, according to the curve implying a prescribed applied voltage to a sensor-output current characteristic, in a reference current operating circuit. And, on the basis of this reference current value, the applied voltage is read from a memory, and said applied voltage is applied to an oxygen sensor 36. Further, following the deviation between the reference current value and the output current value of the sensor 36, the injection fuel amount is corrected. |
