| 摘要 |
A high pressure fluid is used to power an actuator for opening and closing an engine poppet valve when the actuator has a valve stem supporting an upper piston and an adjacent lower piston which axially transverse an actuator housing in response to the flow of high pressure fluid as determined by the position of a control valve. The upper piston has a larger diameter than the lower piston which has a larger diameter than the valve stem. An upper chamber is defined by the upper piston and the actuator housing while a lower chamber is defined by an outside peripheral surface of the lower piston and the actuator housing.
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