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: 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 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: An extremely light and low friction plunger piston for internal combustion engines, particularly Otto-type engines for private cars. The piston has the following ratios and dimensions(H/D)=0.20-0.35(T/D)=0.22-0.38(A/D)=0.15-0.25(B/D)=(A/D)whereinD=piston diameterH=compression height between a top of the head and the gudgeon pin bore axisT=distance from the radially outer boss faces to the piston axisA=axial skirt dimension below annular groove nearest the pin bore axis at a peripheral zone of the skirt extending over an angle .alpha. of 15 to 60 degrees to either side of a connecting rod oscillating planeB=axial skirt dimension below said annular groove in a direction along said gudgeon pin axis;and further wherein the distal end of the skirt is reduced radially over an axial dimension of 10-25% of an axial length of the skirt in said direction along said gudgeon pin axis, said distal end being reduced at its edge by 0.01-0.15 mm.

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.

Abstract: A light metal alloy cast piston including a thermal strut (32, 48, 52) arranged in a shoulder portion of the piston skirt. The thermal strut is composed of an annular fiber-reinforced metal portion in which high-tensile-strength reinforcing fibers are integrally molded. The reinforcing fibers include first fibers (34), such as carbon fibers, having a coefficient of linear expansion substantially smaller than that of the matrix metal alloy, and second fibers (36), such as silicon carbide fibers and alumina fibers, having a flexural or bending strength larger than that of the first fibers. The first fibers primarily serve to restrain thermal expansion of the piston skirt and the second fibers, having a larger bending strength, act to protect the first fibers from excessive bending forces. In a preferred embodiment, the first fibers are located in the inner region of the thermal strut and the second fibers are arranged in the outer region.