IDLING SPEED CONTROL SYSTEM FOR AN AUTOMOTIVE GASOLINE POWERED INTERNAL COMBUSTION ENGINE

摘要

An idling speed control system for an automotive gasoline powered internal combustion engine which system is adapted to vary the opening condition of a carburetor throttle valve in dependence on the variations in the atmospheric pressure. The idling speed control system includes a throttle opening device which is actuated by intake manifold vacuum for opening slightly the carburetor throttle valve during idling operation of the engine, a solenoid control valve for controlling the supply of intake manifold vacuum to the throttle opening device, and a vacuum level control device which is associated with the solenoid control valve and which is arranged to increase the level of the intake manifold vacuum supplied to the throttle opening device when the atmospheric pressure decreases below a predetermined level whereby the carburetor throttle valve is opened slightly more to provide the engine with an air-fuel mixture of proper air-fuel ratio.