Patent ID: 6247461
Filing Date: 2001-06-19
Classification: F02M

Abstract:
A dual port EGR valve for controlling exhaust gas flow to an induction system of an internal combustion engine, said valve comprising:a valve body including a control portion, said control portion having annular ends forming spaced control ports including valve seats aligned on an axis, and axially extending side elements connecting the annular ends and defining a control chamber between the valve seats, the side elements also defining gas passage openings between the valve seats and communicating with the control chamber;a valve member including a shaft and first and second axially spaced heads mounted on the shaft, said shaft centered on said axis for reciprocating motion thereon and said spaced heads being engagable with said valve seats for simultaneously closing said control ports;wherein said control portion and at least a portion of said shaft between said valve heads being made of materials having similar coefficients of thermal expansion so that axial expansion and contraction of the shaft and the control portion between the valve seats due to varying gas temperatures will be essentially equalized and substantially equal seating contact of the spaced heads with their respective seats will be effectively maintained; andwherein said annular ends carry seals rings for engagement with a cooperating recess of a gas passage defining member mounting the EGR valve to seal the peripheries of the annular ends and hold the control portion away from direct contact with the passage defining member to minimize heat transfer therebetween.