A reciprocating engine (1) comprises: a piston ring (5); a piston ring (7) which defines an annular gas chamber (6) in cooperation with the piston ring (5) and which is adjacent to the piston ring (5) such that a pressure-receiving area of a side surface (...

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 s...

A reciprocating engine (1) comprises: a piston ring (5); a piston ring (7) which defines an annular gas chamber (6) in cooperation with the piston ring (5) and which is adjacent to the piston ring (5) such that a pressure-receiving area of a side surface (...

A reciprocating engine (1) includes a cylinder (2); a piston (3) reciprocating in the cylinder (2) in a direction X; a connecting rod (5) rotatably coupled at its small end portion (4) to the piston (3) through a piston pin (4a); ring grooves (7, 8) dispos...