Unitary assembly for control of EGR apparatus for engine

摘要

Exhaust gas recirculation apparatus for an internal combustion engine employs a vacuum responsive control valve in a passageway connecting the engine exhaust passage to the engine intake passage downstream from the throttle valve. A unitary housing comprising a base, a body, and a cap contains an air control valve and a regulating valve each having a flexible diaphragm responsive to differential pressure. The diaphragm for the air control valve is clamped between the cap and the body, and the diaphragm for the regulating valve is clamped between the body and the base. Vacuum pressures on opposite sides of the diaphragm for the air control valve are obtained from a control pipe system and from an air conduit downstream from the air control valve. Vacuum pressures on opposite sides of the diaphragm for the regulating valve are obtained from a vacuum line and from the air conduit upstream from the air control valve. The regulating valve acts to control vacuum pressure in the control pipe system by bleeding vacuum pressure therein through a variable opening into the vacuum line.