Abstract: The invention relates to a reciprocating piston composed of ceramic material for a reciprocating-piston engine with crank drive, wherein the reciprocating piston is rigidly screwed to a piston rod by a screw, wherein between the reciprocating piston and the piston rod there is braced at least one disc composed of metallic material, wherein the screw is composed of a metallic material, wherein the coefficient of thermal expansion ?piston of the material of the reciprocating piston is lower than the coefficient of thermal expansion ?screw of the material of the screw, and the disc is an expansion compensation disc, wherein the coefficient of thermal expansion ?Disc 1;2 of the material of the expansion compensation disc is greater than the coefficient of thermal expansion ?screw of the material of the screw, and to a reciprocating-piston engine having a reciprocating piston of said type, and to a cylinder of a reciprocating-piston engine having a cylinder of said type.

Abstract: The invention relates to an arrangement for sealing off a piston rod, which moves substantially rectilinearly in a reciprocating manner with respect to a passage opening, of a reciprocating-piston machine, having at least two internally clamping sealing rings, which surround the piston rod and are arranged in the region of the passage opening so as to be substantially fixed with respect to a seal housing, and are mounted in the seal housing so as to be movable in a radial direction, and between at least two seal rings there is arranged a spacer ring which is arranged spaced apart from the piston rod, so as to form, together with the seal rings and the piston rod, an accumulation chamber for medium to be sealed off, for example for oil, and the spacer ring has at least one passage for discharging medium out of the accumulation chamber.