FIELD: mechanical engineering; internal combustion piston engines. SUBSTANCE: according to first design version, member changing piston stroke value at working and idle stroke is made in form of two articulated parts with flexible element and element locking one movable part inside the other. Part locking element is made in form of rod lock in rod handles. According to second design version, piston stroke changing member is made on connecting rod and is composed of two parts telescoping relative to each other. According to third design version, piston stroke changing member at working and idle stroke is made on crosshead and is composed of two parts telescoping relative to each other, being installed in points of attachment of connecting rod or crosshead pin from inner side of piston, and connecting rod or crosshead pin is installed in longitudinal guides. EFFECT: increased engine power output owing to making of connecting rod or piston or crosshead with member changing value of piston stroke at working and idle strokes. 9 cl, 9 dwg
