| 摘要 |
PURPOSE:To improve an operability upon switching by a method wherein a hysteresis zone, in which a torque is changed continuously in case the control mode of the air-fuel ratio is switched from the feedback control mode for the logical air-fuel ratio to the lean control mode, is provided. CONSTITUTION:The control circuit, operating and controlling the valve opening time of a fuel injection valve based on the detecting values of an airflow meter and a revolving number sensor, sets a lean flag to one (1) in a step 52 in case a standard injection time Tp is smaller than a predetermined value alpha0 in the step 51, thereafter, the value of the feedback control is operated in the step 53. When a load is increased and Tp>alpha0 in step 51 as well as the lean flag = 1 in step 54 are decided, the lean flag is set in one (1) while Tp<=alpha2 in the step 58, but the lean flag becomes zero (0) in the step 57 when Tp>alpha2. When the load is decreased and Tp becomes Tp<=alpha1, respective lean flags are set in one (1) and a lean operation is effected in the step 59. |
