Exhaust gas recirculation valve with adjustable pressure transducer

Claim 1

In an exhaust gas recirculation valve for an internal combustion engine of the type having a housing defining an exhaust gas inlet and an exhaust gas outlet, a valve operable to control gas flow from the inlet to the outlet, a movable pressure transducer assembly disposed within the housing and operably connected to said valve, and a means for communicating the exhaust gas inlet pressure to the pressure transducer assembly, said transducer comprising: (a) upper housing shell means having an air bleed passage formed therethrough; (b) a lower housing shell; (c) pressure responsive means defining with said upper housing shell an air bleed chamber; (d) bleed valve means operatively connected to said pressure responsive means for controlling flow through said air passage; and (e) said pressure responsive means including, (i) means defining a passage for communicating said air bleed chamber with the atmosphere, (ii) a flexible diaphragm having portions thereof disposed between said upper and lower housing shells, said flexible diaphragm being movable in response to pressure differentials thereacross between a first position in which said bleed valve means is spaced from said air bleed passage means and a second position in which said bleed valve means substantially restricts flow through said air bleed passage means, (iii) biasing means intermediate said upper housing shell and said flexible diaphragm, said biasing means urging said diaphragm toward said first position, (iv) adjustment means rotatably received in and extending through said upper housing shell and selectively positionable relative to said upper housing shell, (v) abutment means intermediate said upper housing shell means and said biasing means, said adjustment means contacting a portion of said abutment means such that as said adjustment means is selectively advanced toward said abutment means said biasing means increasingly urges said diaphragm toward said first position and increases the spacing of said bleed valve means from said air bleed passage, thereby increasing the pressure differential required to move said flexible diaphragm from said first position to said second position.