Vacuum control apparatus

Claim 1

Apparatus for controlling the vacuum of an internal combustion engine having an intake manifold and a gas pedal, comprising an inlet valve for admitting air to the intake manifold, said inlet valve having a first valve member and a second valve member of greater cross-sectional area than said first valve member, an operating solenoid for the inlet valve, said solenoid having a primary winding and a secondary winding, said first valve member being a cylindrical plunger having an upper end encircled by the primary and secondary windings, spring means urging each of said first and second valve members to closed position, an electric circuit connecting the primary and secondary windings to a source of electric current, first switch means in the electric circuit operable to close when the gas pedal is released to engine idling position, second switch means in the electric circuit operable to close when engine speed exceeds normal idling speed, said first and second switch means when closed simultaneously energizing the primary and secondary windings of the solenoid initially to move the first valve member to open position and subsequently to move the second valve member to open position, a normally closed switch connecting the primary winding into the electric circuit, and means actuated in response to the opening movement of the first valve member for opening the normally closed switch.