CONTROLLING DEVICE OF IDLING ENGINE SPEED

摘要

PURPOSE:To prevent torque-down of the engine by increasing the quantity of the fuel for a predetermined period of time when the opening degree of a suction air quantity valve varied in the rising direction by more than a predetermined value by the variation of the load of the engine upon feedback controlling the idling engine speed. CONSTITUTION:Into a deviation amplifier 42 are supplied an output signal from an engine speed setting circuit 42 which sets the target value in correspondence to the action of a load switch 8 and an actual engine speed signal. Based on the deviation between both signals, a throttle valve or an auxiliary air valve provided in a throttle bypass passage is controlled. The operation variation quantity of these valves is supplied to a variation quantity discrimination circuit 44. When the operation variation quantity is more than a predetermined value, the quantity of the fuel from the injection valve 3 is increased for a predetermined period of time through an increasing quantity correction circuit 45.