Intake manifold vacuum control system

Claim 2

In a system for supplying an appropriate amount of fuel-air mixture to an intake manifold of an automotive internal combustion engine, which system comprises a carburetor of variable venturi type with a throttle valve downstream of a variable venturi, means connecting an outlet of the carburetor to said intake manifold and a bypass passage having an inlet located downstream of said venturi and upstream of said throttle valve and an outlet located downstream of said throttle valve; the improvement for controlling flow of a fuel-air mixture through said bypass passage comprising means including in series a flow-metering orifice and valve means for opening and closing said bypass passage, and valve actuating means responsive to a pressure difference between a vacuum in said intake manifold and an ambient atmospheric pressure for holding said valve means closed to close off flow of said fuel-air mixture when said pressure difference is less than about 550 mm of mercury and for opening said valve means to allow flow of said fuel-air mixture when said pressure difference is greater than about 550 mm of mercury, said valve means being per se essentially neutral to said intake manifold vacuum and controlled solely by said actuating means.

Claim 3

A system according to claim 1, in which said valve means and actuating means comprise a hollow valve body having a partition dividing an interior of said body into a diaphragm chamber and a valve chamber, a valve seat in said valve chamber, inlet and outlet passages opening into said valve seat, a valve member movable in said valve chamber between a closed position to close said passages and an open position to open said passages, calibrated spring means normally holding said valve member in said closed position, said valve member having a stem extending through said partition into said diaphragm chamber, a diaphragm having its periphery secured to said body and a central portion connected to said valve stem, said diaphragm dividing said diaphragm chamber into a suction chamber connected with said intake manifold and an air chamber open to the ambient atmosphere, said suction chamber and air chamber being so disposed that said diaphragm is subjected on its one side to said intake manifold vacuum and on its other side to said ambient atmospheric pressure and that said pressure difference tends to move said valve member to said open position against the action of said spring means, said spring means applying a force to hold said valve member in said closed position when said pressure difference acting on said diaphragm is less than about 550 mm of mercury.

Claim 4

A system according to claim 1, in which said valve means comprises a hollow valve body, inlet and outlet passages opening into said valve body and a valve member movable between an open position in which said passages are in communication with each other and a closed position in which said passages are closed, and in which said valve actuating means comprises solenoid means connected with said valve member and holding said valve member in said closed position when said solenoid means is deenergized and in said open position when said solenoid means is energized and electric circuit means for selectively energizing said solenoid means comprising switch means and suction responsive means for operating said switch means comprising a diaphragm chamber, a diaphragm having its periphery secured to said chamber and dividing said chamber into a suctioN chamber connected with said intake manifold and an air chamber open to the ambient atmosphere, calibrated spring means biasing said diaphragm toward said air chamber and means connecting said diaphragm with said switch means for closing said switch means when said pressure difference is sufficient to overcome the biasing force of said spring means, said spring means applying a force for holding said switch means in an open position and thereby said valve member in said closed position when said pressure difference acting on said diaphragm is less than about 550 mm of mercury.