| 摘要 |
A reciprocating engine 1 is so arranged that, in an initial period of an expansion stroke, a high-pressure combustion gas 12 above a piston 2 is introduced via gas passage holes 23 provided in an upper portion 22 of a cylinder inner surface 8 on a thrust side 10 into a gas chamber 4 formed by being encompassed by the cylinder inner surface 8 and a top ring 5, a second ring 6, and a second land 7 of the piston 2, so as to support the piston 2 from the thrust side 10 by the introduced high-pressure combustion gas 12. A half ring 13 is inserted in the gas chamber 4 in a state of being placed on the second land 7 from the thrust side 10 and so as to be movable up and down with clearances 20 above and below, whereby as the piston 2 reciprocates, the half ring 13 moves up and down an amount corresponding to the size of the clearances 20, thereby continually cleaning the inside of the gas chamber 4. |
