| 摘要 |
PURPOSE:To improve drivability, by equipping an engine with a driving piston, which reciprocates in the axial direction cooperatively with a tappet, and a working piston, which drives intake and exhaust valves by the hydraulic pressure, and enabling valve timing of the intake and exhaust valves to be changed in accordance with a load. CONSTITUTION:An engine, when it is in high loaded operation, opens a solenoid valve 14 to supply working fluid to a supply oil part 10 while moves a switching piston 11 rightward against a spring 15 to open a check valve 13. In this way, the working fluid is supplied into an oil pressure generating chamber A through an oil path 30 and a check valve 16, and the engine, in which a control rod 28 is lifted against a spring 29, is set to valve timing when the engine is high loaded. While the engine, when it is in low loaded operation, closes the solenoid valve 14 to move the switching piston 11 leftward by the spring 15, and the engine is set to valve timing, when the engine is low loaded, by closing the check valve 13 while pressing the control rod 28 to be lowered by the spring 29. And the valve timing can be changed by pressing a driving piston 6 by a tappet 3 and lifting a working piston 7.
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