| 摘要 |
The present invention relates to valve control apparatus for use in an engine or compressor to open and close an inlet or exhaust port thereof which comprises valve means (19), an irreversible hydraulic actuator (11) and control means (10, 40). The actuator (11) is connected to the valve means (19) such that the valve means (19) can only operate when driven by the actuator (11). The actuator (11) is irreversible since the piston (16) with the actuator (11) cannot move unless fluid is introduced into one of the chambers of the actuator and removed from the other. |
