Automotive emission control valve with a counter-force mechanism

摘要

A valve assembly (14) has an internal main flow passage through a valve body (24) between a first port (25) and a second port (26), an electric actuator (30), and a valve (86) operated by an armature (58) of the actuator to selectively open and close the passage. A force-balancing mechanism (92) applies to the valve (86) a force that opposes force created by pressure differential between the first and second ports. This mechanism includes an internal chamber (126) bounded in part by a fluid-impermeable movable wall (94) that extends between and is sealed to both the body (24) and the valve (86), and a communication passage (110, 112) that communicates one of the ports (26) to the chamber space when the valve is closing the passage. The valve (86) has a head part (88) and a seal part (90) joined together. The seal part seals the head part to the valve seat (29) when the valve is closing the passage. A retainer part (116) holds the inner margin of the movable wall sealed on the head part. The communication passage extends through the valve to communicate with the chamber space at a region of the valve disposed within the chamber space. The valve also has cushion media (76, 80, 142) that cushions impact of lateral displacements of the armature, an overmold (32) that encloses internal parts, and sonic nozzle structure (28).