| 摘要 |
A system for controlling secondary air supply from an engine-driven air pump through a supply line into the engine exhaust manifold has a control valve with air inlet and outlet ports and a slidable, spring-biased valve seat member defining main and auxiliary air release openings. A first valve member is movable by a valve actuator to control the communication between the air inlet and outlet ports and the main air release opening. A second valve member is resiliently urged by a second spring against the valve seat member to control the communication between the auxiliary air release apertures in the valve seat member and the air release port. The valve actuator has first and second air pressure chambers connected to the secondary air supply line upstream of the secondary air control valve. The first control chamber is connected to the engine intake system. Control valves are provided to control the supply of air pressure into the first and second chambers such that, at least at the initial stage of an engine acceleration, the air release pressure at which the second valve member is moved away from the valve seat member to permit release of the secondary air is increased with resultant increase in the secondary air supply to the engine exhaust system. Pressure delay valves are provided for the control valves whereby the secondary air supply is interrupted when acceleration has lasted for more than a predetermined time.
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