| 摘要 |
PURPOSE:To enhance the lifetime of the seal surface of an exhaust valve to enhance the reliability of a reciprocating engine, by providing such an arrangement that intake and exhaust valves can be automatically controlled to be nonslidably opened and closed in accordance with the movement of a piston under the engagement action between a pawl engaged in a groove which is formed in the peripheral surface of the piston and a guide provided with a cam. CONSTITUTION:An exhaust valve 9 is closed but an intake valve 12 is opened when a piston 1 comes to its top-dead center. Within a groove 3 in the peripheral surface of the piston 1, an engaging pawl 21 on a guide 24 is in a position P1 in the above-mentioned condition where high pressure gas enters into a cylinder 4 through intake and exhaust ports. The pawl 21 changes its position in such an order, that is, P1 P2 P3 P4 P5. The time from P1 P2 corresponds to the intake stroke of the piston 1, and then the guide 2 is rotated during the time from P2 P3 so that the intake port 8 is closed under the force of a spring 13. During the time from P4 P5 the guide is again rotated to open the exhaust port 7. As mentioned above, the valve 9 is automatically opened and closed in association with the motion of the piston 1 without the seal surface 11a of the valve 9 does not slide on the inner peripheral surface of the cylinder 4, and therefore, the mechanical and thermal efficiencies are high. |
