Abstract: In a piston-cylinder assembly with a shaftless piston, the aim is to improve the lateral guidance of the connecting rod, to reduce edge wear and the seizing tendency in the event of fault during the combustion process. Consequently, the piston has at least one supporting ring, form-fittingly on the bosses which guides in the cylinder the piston along with the piston head.

Abstract: A piston having a head with ring grooves, a skirt having hub bores, and a pin, with the following dimensions:L/D=0.45-0.8H/D=0.25-0.5A/D=0.3-0.5T/D=0.45-0.8whereL=maxium length of the pistonD=maximum diameter of the pistonH=compression heightA=maximum skirt height below the bottom ring groove in a peripheral area having the approximate same skirt height of at least 45 degrees on the major thrust face of the piston with approximately symmetrical division of this area on both sides of a plane extending perpendicular to the pin axis and passing through the longitudinal axis of the piston,T=diametrically opposite distance between the hub bore ends located radially on the outside.The skirt bulges along the axis of the piston and has an oval cross-section. An axis of the hub bores is offset slightly towards the major thrust face. The piston includes a horizontal slit, which separates the head from the skirt. In a polar plane perpendicular to the piston axis the skirt has a greater ovality on the minor thrust face.

Abstract: The technical problem is to reduce the operating noise of such a piston. It is solved by means of a piston having the following dimensions: a) A=(0.45-0.65) D; b) H=(0.25-0.4) D; c) A=(0.3-0.4) D; d) A greater than or equal to B; e) T=(0.45-0.8) D; f) the piston ribs between the annular grooves (2, 3, 4) and the rod region with a very narrow operating clearance have, in the case of a hot operating piston, approximately the same clearance in relation to the cylinder operating path. An additional improvement consists in inserting an annular jacket in the piston head in the radial region behind the annular grooves, said jacket consisting of a material having a thermal expension factor less than that of the basic piston material. In a hot operating internal combustion engine, the piston has, in the region of the ribs, a clearance which, in the direction pressure/counter-pressure reaches approximately only 3-5 times the clearance in the very narrow clearance region of the piston rod.

Abstract: A piston structure includes protection of the peripheral edge portion of a lubricant injection nozzle receptacle cut-out. The piston structure employs mechanisms for reinforcing the peripheral edge portion of the cut-out to an extent that can avoid concentration of the stress and thus can avoid the formation of cracks.

Abstract: A light-alloy piston for internal combustion engine, is formed in the piston head with a combustion chamber recess. The stresses which are induced at the rim of the combustion chamber recess by the ignition pressure are reduced by the provision of an inwardly extending blind hole in the portions between the ring groove for the lowermost compression ring and the top apex of the bores in the piston pin bosses.

Abstract: A piston casting for forming a piston for an internal combustion engine or compressor comprises a generally cylindrical crown (10) having a ring belt (11) extending around the crown for the formation therein of one or more piston ring grooves. A gudgeon pin bore (14) extends through the piston casting in a direction normal to the piston axis and two opposed skirt thrust surfaces (17) depend from the ring belt and are symetrically disposed about a plane including the piston axis and normal to the gudgeon pin bore axis. The surfaces extend only part the way around the piston casting and terminate in respective spaced generally axially extending edges (18), each skirt thrust surface being extended circumferentially beyond the associated edges (at 19) at the ends of the edges remote from the crown.

Abstract: In a piston-cylinder assembly with a shaftless piston, the aim is to improve the lateral guidance of the connecting rod, to reduce edge wear and the seizing tendency in the event of fault during the combustion process. Consequently, the piston has at least one supporting ring, form-fittingly on the bosses which guides in the cylinder the piston along with the piston head.