Exhaust cleaning fluid control system and vacuum control valve device for use therein

Claim 1

An exhaust gas cleaning fluid control system including a flow control valve for metering additional air to be supplied to the exhaust manifold of an internal combustion engine in response to vacuum signals and a vacuum control valve device for producing vacuum signals to be applied to a vacuum chamber of the flow control valve, said vacuum control valve comprising; a housing; a diaphragm dividing said housing into a first chamber communicating with the intake manifold of the engine and second chamber communicating with the atmosphere; a valve assembly securely fixed to a center portion of said diaphragm and having a passage intercommunicating said first and second chambers, a spring and a movable valve body biased by said spring to normally close said intercommunicating passage; first and second spring means provided in said first and second chambers for imposing opposite forces on said valve assembly; a solenoid device provided in said second chamber and including a movable member supporting one end of said second spring means; a stopper adapted to push said movable valve body when said valve assembly is displaced a predetermined distance, thereby communicating said first and second chambers with each other through said passage of said valve assembly; said housing including a port formed therein to communicate said first chamber with a vacuum chamber portion of said flow control valve; and said vacuum control valve producing in said first chamber vacuum signals proportional to the intake manifold vacuum of the engine and to on-off signals applied to said solenoid device.