Electromagnetic flow control valve

摘要

A flow control valve for mounting on the intake manifold of an internal combustion engine for controlling a by-pass passage supplying air to the intake manifold of the engine by operating a solenoid in response to output signals from an O2 sensor located in the exhaust manifold. A casing which is mounted on the intake manifold to form the by-pass passage is interiorly provided with a movable member which is operated by energization and de-energization of the solenoid and biased to abut against a fixed member in the casing by the action of a first spring when the solenoid is in the de-energized state. Further provided in the casing are a slide member which is slidable along the fixed member and a pressure chamber defined by the diaphragm one peripheral edge of which is secured to the slide member, the pressure chamber being communicated with the intake manifold to receive the intake manifold vacuum therein. The slide member is biased by a second spring and pushed forward to retract the movable member against the action of the first spring and to complete the by-pass passage through the casing when the engine is switched off or when atmospheric pressure prevails in the intake manifold. During operation of the internal combustion engine, the intake manifold vacuum is admitted into the pressure chamber, retracting the slide member against the action of the second spring to free the first spring.