| 摘要 |
PURPOSE:To obtain a smooth change between partial cylinder operation and total cylinder operation by operating a valve, which releases or closes the hydraulic pressure of a plunger supporting a rocker arm, when the rocker arm is pressed with a cam. CONSTITUTION:A suction valve 13 is released when a rocker arm 12, having a plunger 14 as its fulcrum, is pressed down by a cam 11. The plunger 16 is supported the hydraulic pressure, which is produced when the oil is supplied to a chamber 16 situated below the plunger 14 and when the chamber 16 is tightly closed or when the valve 19 closes a hole 21. A needle 23, which projects when a solenoid 25 is excited, is arranged, facing the valve 19. When the total cylinder operation is changed to the partial operation, a crank angle sensor 30 detects the time during which a projected surface 11a presses down the rocker arm 12. then the solenoid 25 is excited, thereby projecting the needle 23. As a result, the valve 19 is released, resisting the force of the spring 20, thereby discharging the oil in the chamber 16 and suspending the release of the valve 13.
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