| 摘要 |
PURPOSE:To make a follow-up lag in feedback control compensable as well as to improve emission control performance for exhaust gas ever so high, by setting a control valve, controlling secondary air feed to an exhaust pipe, to a state of being opened for the specified time long at a time when a throttle valve shifts from closeness to openness. CONSTITUTION:When a throttle valve 10b is in a state of being closed, a suction pressure selector valve 10g is opened according to an L signal out of a throttle valve opening sensor TPS1 via an electronic control unit 1, whereby suction pressure is led into a diaphragm chamber 10fD of a secondary air control valve 10f. Therefore, the said control valve 10f is opened, feeding an exhaust manifold 10k with secondary air via an intake pipe 10b. Under this condition, when starting and acceleration take place, the suction pressure selector valve 10g is closed according to an H signal out of the sensor TPS1, and the suction pressure is held inside the said chamber 10f, thus the valve 10f is opened and kept intact. And, when it is after the elapse of the specified time and an oxygen sensor OS1 detects a lean state, the suction pressure selector valve 10g is reopened, and nearly atmospheric pressure is led into the chamber 10fD whereby the valve 10f is closed.
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