Patent ID: 6460521
Filing Date: 2002-10-08
Classification: F02M,F16K

Abstract:
An emission control valve for controlling flow of gases with respect to combustion chamber space of an internal combustion engine comprising:a valve body comprising a passageway having an inlet port for receiving gases and an outlet port for delivering gases to the combustion chamber space, a valve element that is selectively positioned to selectively restrict the passage, and a mechanism for selectively positioning the valve element comprising a solenoid having an electromagnet coil, a stator that is associated with the coil and that has a magnetic circuit comprising an air gap for conducting magnetic flux generated in the stator when electric current flows in the coil, and an armature that is disposed in the air gap to be displaced along an imaginary centerline by the magnetic flux and that comprises a wall spaced radially from the centerline, and wherein the stator comprises a pole piece that is cooperatively associated with the armature wall and that comprises an inner wall disposed radially inward of the armature wall and an outer wall disposed radially outward of the armature wall, one portion of the air gap flux is conducted from the outer wall to the armature wall, another portion of the air gap flux is conducted from the inner wall to the armature wall, and at least one of the pole piece walls has a radial thickness that changes as a function of its location along the centerline.