Idling speed control device of an internal combustion engine

摘要

An idling speed control device of an internal combustion engine comprising a bypass passage which interconnects the intake passage located upstream of the throttle valve to the intake passage located downstream of the throttle valve. A flow control valve is arranged in the bypass passage and actuated by a step motor for controlling the amount of air flowing within the bypass passage to maintain the idling speed of an engine at a predetermined speed. The step motor comprises a screw threaded valve shaft and a rotor rotatably mounted on the valve shaft and having a screw threaded center hole which is in engagement with the screw threads of the valve shaft. A pair of stop pins, each being engageable with the corresponding end face of the rotor, is fixed onto the valve shaft.