| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent occurrence of pressure loss by a vacuum control valve and enlargement of a vacuum source by providing a bypass means for bypassing the vacuum control valve when maximum vacuum is supplied to a vacuum actuator for a connection pipe for connecting the vacuum source with the vacuum actuator via the vacuum control valve. SOLUTION: Each variable nozzle 2 for controlling exhaust gas pressure of a variable-capacity-type turbo charger to a turbine 1 is connected with a common ring member 3 through a link mechanism 4, and its opening is controlled by rotation of the ring member 3 by a vacuum actuator 10. When each variable nozzle 2 has a minimum opening, a control device 20 stops control of a vacuum control valve 24 and exchanges a three-way valve 25. Therefore, a bypass passage 26 is communicated with the vacuum actuator side rather than the three-way valve 25 of a connection pipe 21, and vacuum in a vacuum tank 20 is directly supplied to a vacuum chamber 10c of the vacuum actuator 10. Thus, because vacuum of the vacuum chamber 10c can be kept equal to that of the vacuum tank 20, enlargement of a vacuum pump 23 can be prevented.</p> |
