STELLVORRICHTUNG FUER EINE ABGASREINIGUNGSANLAGE

摘要

An exhaust gas control actuator wherein the feed of secondary air fed to an exhaust piping is controlled by an oxygen concentration detector disposed in the stream of exhaust gas of an internal combustion engine and an air-fuel ratio of the exhaust gas entering a catalyst disposed downstream of the exhaust piping is maintained within a given range. The actuator comprises a flow control valve and a flow control device for controlling the flow control valve. The flow control valve is provided with a flow-in port communicated with an air pump and the valve body, a flow-out port communicated with an exhaust manifold and a bypass port communicated with an air cleaner. Furthermore, the flow control device is actuated by an electronic control circuit and comprises an actuating chamber partitioned by a diaphragm for actuating the valve body and including a negative pressure introducing port communicated with an intake manifold and an atmosphere introducing port constantly communicated with atmosphere, and a nozzle flapper mechanism provided in the actuating chamber and varying resistances to flow through the negative pressure introducing port and the atmosphere introducing port in accordance with the actuating position of the valve body in such a manner that an output signal of the oxygen concentration detector in negatively fed back to the feed of secondary air.