Patent ID: 6772743
Filing Date: 2004-08-10
Classification: F02M

Abstract:
An emission control valve for controlling flow of gases with respect to combustion chamber space of an internal combustion engine comprising:a housing comprising a passage having an inlet port for receiving gases, an outlet port for delivering gases to the combustion chamber space, and a valve element that is selectively positioned by an electric actuator to selectively restrict the passage, wherein, the actuator comprises a solenoid having an electric coil, stator structure, and a positioning mechanism, including an armature that is selectively positionable along an axis, for selectively positioning the valve element, the stator structure and the armature cooperatively form a magnetic circuit in which the coil, when energized by electric current, creates magnetic flux for selectively positioning the armature along the axis, the stator structure is separated from the armature by an air gap that includes a non-ferromagnetic guide sleeve that is substantially concentric with the axis and in surface-to-surface contact with the armature for guiding armature motion along the axis, the stator structure comprises a pole piece having a cylindrical hub, and the guide sleeve comprises a radially outward protruding bead having surface-to surface contact with the hub to provide a minimum air gap between the armature and hub by radial spacing of the guide sleeve from the hub along an axial extent of the guide sleeve immediately adjoining the bead.