| 摘要 |
PURPOSE:To enhance the startability of an engine by opening widely an intake secondary air control valve when a rest time before engine startup is equal to or longer than a predetermined time at a high temperature start, and thereby compensating for a fuel-rich condition due to an increase in evaporated fuel during a long interval from engine rest to restart. CONSTITUTION:A control circuit 20 is connected with an intake absolute pressure sensor 10, a crank angle sensor 11, a water temperature sensor 12, an intake temperature sensor 13, an O2 sensor 14 and an ignition switch 7, and controls an air-fuel ratio via a linear type electromagnetic valve 9 on an air intake secondary air supply passage 8. The control circuit 20 measures time elapsed since the ignition switch 7 is turned OFF and saves and holds the time, if it is longer than a predetermined time. When cooling water temperature is equal to or above a predetermined level and the ignition switch 7 has been again turned ON, the electromagnetic valve 9 is fully opened, if a rest time until operation resumption is equal to or longer than a predetermined time. The electromagnetic valve 9 is closed, if the rest time is shorter than the predetermined time.
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