| 摘要 |
PURPOSE:To operate an actuator quickly by introducing pressure to a chamber with a larger volume earlier than to the other chamber by predetermined time when positive pressure is applied to one of the two chambers separated by a diaphragm and negative pressure is applied to the other to drive the actuator. CONSTITUTION:When each of three way valves 14, 43 allows each of pressure introduction pipes 13, 42 to be in communication with atmosphere, atmospheric pressure is introduced to an actuator 12 whose spring force causes an exhaust cut valve 11 to be closed, stopping exhaust gas from being supplied to a turbine 10b disposed in a secondary branch exhaust passage to allow only a primary side turbo charger 9 to be operated. In this case, when the exhaust cut valve 11 is shifted from close state to open state, operating timing for each of the three way valves 14, 43 is controlled by a control unit 40. That is, the three way valve 14 is first operated to introduce negative pressure to a negative pressure chamber with a larger volume in the actuator 12. Then, the three way valve 43 is operated to introduce positive pressure to a positive pressure chamber 12b with a smaller volume. |
