| 摘要 |
PURPOSE:To perform reliable control of the opening and closing timing of a scavenging hole, by a method wherein a hydraulic actuator for driving a control valve for opening and closing the scavenging hole is driven by means of an oil pressure fed from a hydraulic cylinder driven by a piston at a time when a piston is positioned at a bottom dead center. CONSTITUTION:A control valve 3 is situated on the outer periphery of a scavenging hole 2 provided in a cylinder liner 1, and is adapted to be opened and closed through the working of a hydraulic actuator 5. A hydraulic cylinder 4 is provided facing the under surface of a piston 8, and the hydraulic actuator, a check valve 6, and a throttle 7 positioned in parallel to the check valve are provided. When, during the terminal stage of the lowering stroke of the piston 8, the hydraulic cylinder 4 is pressed by means of the under surface of the piston 8, pressure oil causes opening of the check valve 6 to immediately actuate the hydraulic actuator 5 and therefore, the control valve 3 is opened proportionally to movement of the piston 8 before the bottom dead center of the piston 8. During the raising stroke of the piston 8, oil in the hydraulic actuator 5 is throttled by means of the throttle 7 and therefore, the control valve 3 is gradually closed.
|
