Abstract: A piston for medium-speed internal combustion engines having a ring groove for receiving a compression piston ring. The upper and lower flanks of the ring groove when the engine is cold deviate from a plane-parallel position in relation to the adjoining upper and lower flanks respectively of the ring to such an extent that under the mechanical and thermal loading of the combustion gases in operation of the engine under rated load they are deformed into a position plane-parallel with the flanks of the ring.

Abstract: Piston for internal combustion engines having a piston body consisting of light metal and a crown plate consisting of a metal of lower thermal conductivity which is secured axially to the piston body by means of necked-down screws and centered radially in relation to the piston body by means of an annular fit, and in which the outer ring of the fit is formed by the crown plate in the region of the sliding surface and the inner ring of the fit is formed by the piston body, in which at room temperature a gap widening in the direction towards the piston foot is provided between the annular surfaces of crown plate and piston body meeting in the annular fit, in such a way that the annular surfaces lie firmly against one another only at their ends pointing towards the piston head, and that this gap is reduced at working temperature.

Abstract: The invention provides a piston formed by casting a metal piston body under pressure around an insert, the body being made of aluminium or aluminium alloy and the insert being made of a porous layer having a thickness 20 to 50 times the pore diameter and completely filled with the piston body metal which projects from the body into the pores of the insert.

Abstract: An aluminium 2-stroke engine cylinder and the crank case assembly is provided, in which a cylinder flange rests in sealing manner over its entire area upon a corresponding counter-surface of the crank case and a deformable packing lies between the sealing surfaces and in which the flange is tightened to the crank case by means of screws. The mutually opposite sealing surfaces of flange and crank case are slightly inclined in relation to one another in such a way that the distance between the sealing surfaces is greater radially inwards than radially outwards.

Abstract: A method for electroplating and mechanically honing surfaces of a light-ay workpiece is provided comprising placing the workpiece within a honing machine having honing stones and an electrolytic circuit including an electrolyte, applying to said workpiece a first coating by electrolytic deposition within said electrolyte with the honing stones disengaged from said surfaces, and effecting simultaneous honing and electrolytic deposition of a second coating by means of said electrolyte. In this manner the deposition of the necessary basic coating is combined with the procedural step of the simultaneous electroplating and mechanical honing in such a way that the basic coating is deposited in the hone-forming machine itself and with the same electrolytic fluid, so that there is no need for a preliminary plating in an additional unit that is separate from the hone-forming machine.

Abstract: The invention provides a method of testing silicon distribution in aluminium-silicon alloys by drawing a conductor across the surface of the alloy and measuring the changes of electric resistance between the conductor and the alloy.

Abstract: An aluminium-silicon alloy casting in which zones formed so as to have a particularly fine-grained structure are cooled by way of individual thin-walled mould wall portions, which are prevented from dissolving completely by the melt and are intermetallically bonded to the casting and are detachable from the finished casting only in a destructive manner.

Abstract: A piston having an uncooled annular insert adjoining a main combustion chamber between piston and cylinder cover, combustion cavities arranged in the crown of the piston and an injection passage opening into the combustion cavities wherein, in the zones covered by the annular insert (5), laterally of the injection passage (8), outside the combustion cavities (6), the distance between the lower edge of the annular insert (5) and the crown surface of the piston (1) is increased by 0.15 to 0.7% of the piston diameter in comparison with the distance between the main surfaces of piston (1) and the cover of the cylinder (2).

Abstract: A light-metal piston with parts hard-eloxated to increase their resistance to heat and mechanically reinforced to the depth of the hard eloxation.

Abstract: A piston comprising a lower part with a bore having a concave surface against which abuts the convex surface of a head of an expansion socket, the center of curvature of the concave surface lying on the axis of the bore and the head being formed in two halves with each half having a center of curvature lying offset from the axis of the bore.

Abstract: This invention provides an austenitic cast iron especially suitable for reinforcements in aluminium pistons and containing 2-6% Ni, 1.8 to 4.0% C, 1-3% Si, 6-12% Mn, 5-7% Cu, less than 0.08% Cr, 0.3 to 2% Al and 0.05 to 0.3% Ti.

Abstract: An annular reinforcement for piston ring grooves, the reinforcement being provided with inclined bores so that when the reinforcement is built into the piston and the bores are filled with material integral with the piston, movement of the reinforcement both in the axial and radial directions is resisted.

Abstract: In a liquid-cooled cylinder sleeve for combustion engines of the reciprocating piston type, the provision of a cylinder wall thickness which increases in a rotationally symmetrical manner along its periphery in the direction of the line of intersection of the piston pivoting plane passing through the longitudinal axis of the cylinder and the wall of the cylinder sleeve.

Abstract: Welding method and apparatus for detecting the penetration depth of an electron beam weld, in which X-rays which occur are guided through several plates of an absorption device to a ray receiver, the plates comprising of plurality of bores of equal diameter, which are arranged in their position to one another in such a way that the center lines of corresponding bores on the same level are in exact alignment and that the ray receiver, absorption device and workpiece are aligned in parallel with one another and are co-ordinated to one another in height.

Abstract: A piston has a pair of support members extending away from the piston head offset from a piston ring portion, a piston rod being carried on a connecting rod which is clamped between the support members by a bolt. The bolt is loosely received in a bore in the connecting rod, the force between the piston and the piston rod being taken by a frictional force between the connecting rod and the support members to prevent a bending force being applied to the bolt.

Abstract: A composite casting is produced by electrodepositing a wear resistance material onto a core, immersing the core in an aluminium melt and then casting an aluminium alloy around the core, before detaching the latter. The wear resistant layer may be given a roughened surface before immersing in the aluminium melt, by increasing the current density in the later stages of the depositing. The method may be used for casting light metal cylinders for internal combustion engines.

Abstract: A combustion engine with a piston forming the combustion chamber, means for protecting the edge of the opening of the combustion chamber against cracks being arranged so that they only take effect in the peripheral zones of the edge which are adjacent the supporting sides of the piston.