Linear solenoid actuator for an exhaust gas recirculation valve

Abstract

A valve assembly is disclosed for metering exhaust gas to the intake manifold of an internal combustion engine. The valve assembly has a base which includes a passage communicating between the intake manifold and the exhaust manifold of the engine. The passage has a valve seat which is operable with a valve member to meter the flow of exhaust gas through the passage to the intake manifold. An actuator assembly is mounted to the base and is operably connected to the valve member to move the valve member into and out of engagement with the valve seat. The actuator assembly includes a solenoid having a magnetic circuit comprising stationary primary and secondary pole pieces and a moveable armature. The primary pole piece includes an inner cylindrical wall operable to define, with the armature, a fixed radial gap for the passage of magnetic flux, and a tapered outer wall operable to increase the mass of the magnetic circuit, through which flux may pass, as the armature moves axially within cylindrical inner primary pole piece includes a n inwardly tapered, conical portion which operates, with an associated conical end of the moveable armature, to increase the axial opening force on the armature by establishing a secondary gap for the passage of magnetic flux as the armature approaches the conical tapered portion of the cylindrical wall. In addition, leakage flux is directed from said conical portion of said armature to said cylindrical inner wall across the entire range of motion of the armature to increase the axial force on said armature during operation of the valve.