| 摘要 |
PURPOSE:To simplify a valve driving mechanism, by a method wherein, in an engine having an exhaust valve opened and closed by hydraulic piston, an oil pressure is generated by a pressure in a cylinder to open the exhaust valve, and an on-off valve is situated in a hydraulic line to hold an oil pressure at a proper value. CONSTITUTION:An exhaust valve 13, located at the top part of a cylinder, is opened in a way that an oil pressure, generated by a plunger 44 interlocking with a piston 42 moved by means of a pressure in a cylinder exerted on an actuating gas hole 41 formed in the lower side wall of a cylinder block 11, is exerted on a hyraulic piston 18. Since the oil pressure is temporarily held by a rotary pipe control valve 47 mounted in the middle of a high pressure pipe 46, even if a piston 12 is raised and the hole 41 is rendered open to a crank chamber, release of the exhaust valve 13 is maintained. The valve 47 is opened at a given timing, and the exhaust valve is closed through the force of a spring 16. An oil pressure generating mechanism eliminates a driving part, e.g., cam, resulting in simplification of a device.
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