Dr. Ing. H.c. F. Porsche Aktiengesellschaft

Klaus Schellmann

Heinz Schulze

Wolfgang Schmid

Rainer List

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. In accordance with one embodiment, the piston system comprises at least three pistons, at least a drive piston being provided in addition to the power and actuating pistons, the drive piston having the piston valve therein.

Valve control for internal combustion engines

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.

Multicylinder internal combustion engine, especially for automobiles and

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.

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Hemmingen, Germany

Klaus Schellmann