Abstract: In a piston comprising a top part, which includes at least the piston head and the ring-carrying portion, and a bottom part, which is connected to the top part by suitable means, the adequate lubrication of the piston pin, which is firmly connected to the connecting rod is ensured in that the piston pin is movably mounted in hub segments, which are connected to the bottom part, and in a recess which has the shape of a segment of a cylinder and is formed in a plate that is made of heat-insulating material and inserted on the inside surface of the piston head.

Abstract: A light alloy piston for internal combustion engines has a skirt which is closed at its lower end and at locations disposed adjacent to the bosses on both sides of the horizontal plane through the piston pin is set back so as to form respective recesses. In order to avoid a retention of oil in the recesses those end portions of the skirt which adjoin the recesses are inwardly offset from the outside peripheral surface of the piston.

Abstract: In a light alloy piston having a convex and oval external shape, the piston skirt has in the cold state a larger running clearance at its top end than at its bottom end. In order to reduce the friction loss of such piston, the piston skirt has a larger ovalness adjacent to the horizontal plane extending through the pin axis than in the remaining regions of the piston skirt.

Abstract: A valve control for internal combustion engines comprising a hydraulic arrangement between a cam shaft and a cylinder head valve, the hydraulic arrangement including a piston system having at least a power piston cooperable with the cam shaft and an activating piston, a housing within which at least the actuating piston of the piston assembly is contained and a damping means for controlling valve seating operation. The hydraulic arrangement forms part of a means for varying the stroke and opening time of the cylinder head valve in response to at least one operating parameter of the internal combustion engine, and the means for varying the stroke and opening time also includes a throttle element for influencing the piston system, the throttle element being controlled by the noted at least one operating parameter of the internal combustion engine.

Abstract: A multicylinder internal combustion engine is provided with fuel-air mixture feed devices associated with two different cylinders or groups of cylinders, and an exhaust conduit system in which two catalyzers are disposed, one downstream of the other. The exhaust produced by the first group of cylinders impinges on both catalyzers, while the exhaust of the second group of cylinders is fed through only the second catalyzer. During a predetermined partial load range, fuel is supplied only to one of the cylinder groups, while both cylinder groups are fed with fuel once this load range is exceeded. In a preferred embodiment, the turning on of fuel to the second cylinder group is effectuated by a cam disk that also serves the function of simultaneously controlling the supply of air through throttle valves to the respective cylinder groups.

Abstract: A device for the adjustment of the ignition time of an internal combustion engine as a function of the vacuum in the intake line which is provided with a flow regulator in the form of a throttle valve or the like.