| 摘要 |
PURPOSE:To make building up of torque sharp and to improve acceleration responsiveness, by introducing the atmospheric pressure into a pressure chamber of an equipment for actuating a bypass control valve of a turbocharger through a directional control valve when a rapid acceleration is effected. CONSTITUTION:A bypass passage 24 for bypassing a turbocharger 22 disposed in an intake air passage is provided with a bypass control valve 38. A pressure chamber 44 of an actuator for actuating the control valve 38 is connected with a signal port 62 and an atmospheric pressure port 58 downstream of a throttle valve 18 through an electromagnetic directional control valve 50. A control unit 34 is supplied with an opening degree of the throttle valve 18 and switches the directional control valve 50 at a rapid acceleration wherein a change of a valve opening speed is greater than a prescribed value so that the pressure chamber 44 communicates with the atmospheric pressure port 58. With such an arrangement, since the bypass control valve is closed rapidly, building up of torque is made sharp, whereby acceleration responsiveness is improved.
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