| 摘要 |
PURPOSE: A hydraulic-operated device of an exhaust valve is provided to accurately control a valve and avoid the problems in that very large load is applied to both a valve actuator and a hydraulic component so that a specified component rapidly wears away in an undesirable degree. CONSTITUTION: A hydraulic-operated device of an exhaust valve in an internal combustion engine comprises a valve pump(8) having a pressure chamber(30), and in the pressure chamber, a port(29) is selectively connected to a high pressure supply source for hydraulic fluid or a return pipe through a control valve. A service piston in the valve pump separates the pressure chamber from a hydraulic volume part communicating with a pressure chamber in a hydraulic actuator to a main shaft of the exhaust valve through a pressure conduit(6). A second service piston limits a flow of hydraulic fluid from the port to the pressure chamber at the start position.
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