| 摘要 |
PURPOSE:To provide an apparatus including a throttle positioner for controlling the opening of a throttle valve so that the throttle valve is not closed to an opening for idling operation, which is capable of reducing the amount of HC discharged together with exhaust gas, by employing such an arrangement that the throttle positioner is operable in a low-speed operational range of an engine in addition to a vehicle-speed controlling region. CONSTITUTION:When a throttle valve 2 is closed by bringing back an accelerator pedal at the time of low-speed operation of an engine when the vehicle speed is lower than, for instance, 30km/h, the atmospheric pressure is acted to a port 5 and tends to be transmitted to a diaphragm chamber 8 of a throttle positioner. However, since a negative pressure is retained for a while in the diaphragm chamber 8 by the delay function of a vacuum transmitting valve 6, the throttle valve 2 is prevented from restoring the idle opening immediately. On the other hand, at the time of high-speed operation of the engine when the vehicle speed is higher than, for instance, 30km/h, a vacuum switching valve 10 is turned ON by a computer 12, so that the suction vacuum is transmitted to the diaphragm chamber 8 via a gas filter 18 and a three-way circuit 17 and the opening of the throttle valve is kept at a required angle. |
