Abstract: A piston of an internal combustion engine, comprises a skirt portion in sliding-contact with a cylinder wall, an inner crown-plus-boss portion having a crown portion and piston-pin boss portions, and a stay portion interconnecting the skirt portion and the inner crown-plus-boss portion at a lower portion of the piston. Also provided is an annular partition groove through which a rim of the skirt portion and the inner crown-plus-boss portion are partitioned all around the circumference of the upper portion of the piston. A thermal-expansion absorption ring is tightly fitted into the annular partition groove in a gas tight-fashion. The top face of the inner crown-plus-boss portion, the flat face of the rim of the skirt portion, and the top wall of the thermal-expansion absorption ring serve as a piston crown.

Abstract: The aim is to improve the strength of an intermetallic bond between engine component made from an aluminium alloy and a reinforcing element made from austenitic cast iron. For that purpose, the reinforcing element is annealed in a decarbonising atmosphere before the known prior art alfin process is carried out, in order to obtain an alfin layer largely free of graphite scales.

Abstract: A piston, e.g. for an internal combustion engine, comprises a crown (16) and a skirt (12). The skirt (12) has an aperture (22) in which an insert (14) of a different material from the remainder of the skirt is secured. The insert (14) may be of plastics material injection moulded into a metal skirt. The insert (14) provides a plurality of pads (34) which extend from a thrust surface of the skirt so that the pads can transmit lateral forces and cause lubricant to be forced over the pads by hydrodynamic action during reciprocation of the piston.

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: A piston comprises a crown part, a piston under part, a first shoulder at a thrust side formed between the crown part and the piston under part, a second shoulder at an anti-thrust side formed between the crown part and the piston under part, a first in-low part at the thrust side formed in the piston under part, and a second in-low part at the anti-thrust side formed in the piston under part, wherein a thickness of the first shoulder is formed thinner than a thickness of the second shoulder, and a height of the first in-low part is formed smaller than a height of the second in-low part.

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 light metal piston for internal combustion engines has a pair of inserts on the inside of upper piston skirt made of a material of lower thermal expansion coefficient than that of the light metal, such as steel. Each insert has a pair of bands which are joined by a connecting portion of the insert in the region of the gudgeon pin boss. Each band extends circumferentially away from the gudgeon pin boss, so as to control thermal expansion of the piston skirt. A free end of each band are bent inwardly, so that the insert can be set firmly on the mold core of the piston during casting operation by snapping the bent portions of the insert into the grooves on the mold core.

Abstract: In expansion-controlled light alloy pistons for internal combustion engines, expansion control elements made of steel are bonded to the carrying portions of the cast skirt on the inside peripheral surface thereof and are embedded in the hubs of the piston pin bosses. To provide for an optimum expansion control action throughout the height of the piston skirt, the expansion control elements are provided on both sides of the plane of oscillation of the connecting rod with an aperture, which is open toward the end of the skirt and has a height amounting to at least 30% of the height of the expansion control elements. Said aperture has a peripheral dimension amounting to more than 10% of the piston diameter. Projections for supporting the expansion control element at its edges defining the aperture protrude into the latter.

Abstract: A light metal alloy cast piston comprises a thermal strut provided in the shoulder portion of the piston skirt. The thermal strut is composed of a fiber reinforced metal portion containing high tensile strength fibers integrally molded in the matrix metal. The piston is shaped in such a manner that the inner periphery of the thermal strut is exposed toward the inside of the piston skirt, except for the regions at the piston pin bosses, to avoid the presence of non-reinforced metal a the inside of the thermal strut. This arrangement prevents the formation of cracks along the inner periphery of the thermal strut.

Abstract: In a plunger piston for internal combustion engines, having a regulating strip in the piston body, the regulating strip is arranged in the axial middle third of the height of the piston body and the regulating effect is designed so that the piston body possesses its narrowest installation play uniformly at the level of the regulating strip equally in the cold installation state and in the engine operation. Above and below this region with minimum installation play the piston body possesses spherically retracted end regions at its upper and lower ends for the generation of hydrodynamic lubricant oil wedges.