EGR Control systems for diesel engines

Claim 1

In an automotive vehicle having a diesel engine, a throttle system actuable to control the engine speed, a vacuum pump driven by the engine and forming, at least in part, a vacuum pressure source, and an EGR system having an EGR valve assembly operable to recirculate exhaust gas to the engine air intake in relation to the degree of valve operating vacuum pressure communicated thereto and, a valve controller for governing the level of vacuum pressure communicated to the EGR valve from the vacuum pressure source, said valve controller comprising: (a) a housing defining an output port communicating with the EGR valve for supplying operating pressure thereto, an input port communicating with the vacuum pressure source, and an input port communicating with ambient atmospheric pressure; (b) a regulator valving means in said housing including a control member movable to control communication between said output port and said input ports to govern the valve operating vacuum pressure level, said control member acted upon by differential pressure force between the output pressure and the pressure at one of said input ports; and, (c) throttle position responsive means for exerting actuating force on said control member which varies as a predetermined function of throttle system operation to alter the output pressure, said throttle position responsive means comprising: (i) a lever connected to said throttle system; (ii) a cam supported by said housing and driven by said lever; and, (iii) a resiliently deflectable force transmitting element between said cam and said control member for applying force to said control member depending on the position of said lever, said force transmitting element effective to change the force applied to said control member in response to change in the cam position with said control member moving in response thereto to establish a changed output pressure to said EGR valve at which the forces acting on said control member are balanced.

Claim 4

The system claimed in claims 1 or 2 wherein said force transmitting element comprises a resilient spring element extending between said cam and said regulator member and further including an adjustably movable calibration element engageable with said spring element.