Patent ID: 6178956
Filing Date: 2001-01-30
Classification: F02M

Abstract:
A solenoid operated exhaust gas recirculation valve for an internal combustion engine, comprising:a valve housing having a central chamber, an inlet passage, an outlet passage, and an exhaust gas inlet passage having an inlet opening, each of said passages being in fluid communication with said central chamber;a valve member positioned in and moveable within said central chamber, said valve member having a hollow valve stem and a valve head, said valve head having at least one opening formed therein to receive exhaust gas therethrough such that it can pass into said hollow valve stem;a solenoid assembly for reciprocating said moveable valve member between a closed position wherein said valve head engages a valve seat located at said exhaust gas inlet opening to prevent the flow of exhaust gas from said exhaust gas inlet passage into said central chamber and a fully open position wherein said valve head is disposed from said valve seat allowing exhaust gas to flow from said exhaust gas inlet passage into said central chamber to mix with air flowing in from said inlet passage;said valve member being subjected to an initial bias which produces a force tending to move the moveable valve member toward the closed position;an expandable device that produces a force responsive to said initial bias to produce a force tending to urge the valve away from the closed position, said expandable device having an upper and a lower surface, whereby exhaust gas passing through said hollow valve stem, exerts a downward force on said upper surface of said expandable device to counteract the pressure exerted by the exhaust gas on said valve head, whereby at all positions of the valve member between the closed and fully open positions, the pressures acting on the valve member and the expandable device are equal so that said valve member remains in the desired position to allow the appropriate amount of exhaust gas to enter said central chamber.