PURPOSE: To prevent an engine stop caused by the over lean, by controlling a linear type flow regulating valve, provided in an intake secondary air passage, being based on the opening and its time which are set in accordance with a change speed of operative parameters in the time of deceleration.
CONSTITUTION: A control circuit 20 inputs detection values from a negative pressure switch 7 positioned just in the upstream of a throttle valve 3, intake absolute pressure sensor 10, crank angle sensor 11, cooling water temperature sensor 12, O2 sensor 14, car speed sensor 16, etc., and when a feedback control condition is established, a feedback control of air-fuel ratio is performed through a linear type solenoid valve 9 provided in an intake secondary air supply passage 8. When deceleration is detected, the linear type solenoid valve 9, setting its opening and control time being based on a change amount of intake absolute pressure, is controlled to the preset opening in accordance with a degree of the deceleration only for the preset time.
SATO TOSHIO
HASEBE HIROSHI
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