Described herein is a system for variable actuation of an engine valve of an internal-combustion engine, where the system is able to actuate the engine valves, selectively, in a four-stroke operating mode and in a two-stroke operating mode, on the basis of the operating conditions of the engine.

Described herein is a system for variable actuation of an engine valve of an internal-combustion engine, where the system is able to actuate the engine valves, selectively, in a four-stroke operating mode and in a two-stroke operating mode, on the basis of the operating conditions of the engine.

Described herein is a system for variable actuation of an engine valve of an internal-combustion engine, where the system is able to actuate the engine valves, selectively, in a four-stroke operating mode and in a two-stroke operating mode, on the basis of the operating conditions of the engine.

The invention relates to a volume-controlled four-stroke reciprocating internal combustion engine comprising a first cylinder, in which a first piston that is operationally connected to a crankshaft via a first connecting rod, is arranged so as to be displaceable in a reciprocating motion, and at least one second cylinder, in which a second piston that is operationally connected to the crankshaft via a second connecting rod is arranged so as to be displaceable in a reciprocating motion. The engine further includes a fresh air tract for the second cylinder, in which an expansion/compression machine is arranged in the direction of flow of fresh air before a gas exchange inlet valve of the second cylinder, wherein the expansion/compression machine is the first cylinder. The volume-controlled internal combustion engine as per the invention has great potential for saving fuel and thereby for reducing CO.sub.2.

The invention relates to a volume-controlled four-stroke reciprocating internal combustion engine comprising a first cylinder, in which a first piston that is operationally connected to a crankshaft via a first connecting rod, is arranged so as to be displaceable in a reciprocating motion, and at least one second cylinder, in which a second piston that is operationally connected to the crankshaft via a second connecting rod is arranged so as to be displaceable in a reciprocating motion. The engine further includes a fresh air tract for the second cylinder, in which an expansion/compression machine is arranged in the direction of flow of fresh air before a gas exchange inlet valve of the second cylinder, wherein the expansion/compression machine is the first cylinder. The volume-controlled internal combustion engine as per the invention has great potential for saving fuel and thereby for reducing CO.sub.2.

A combustion engine comprises a main combustion cylinder configured to enable a piston to move therein; a main valve configured to move in the main combustion cylinder; an upper non-combustion chamber operatively adjacent to the main combustion cylinder; an upper intake valve configured to move in the upper non-combustion chamber and to communicate with an intake manifold; and an upper exhaust valve configured to move in the upper non-combustion chamber and to communicate with an exhaust manifold.

A combustion engine comprises a main combustion cylinder configured to enable a piston to move therein; a main valve configured to move in the main combustion cylinder; an upper non-combustion chamber operatively adjacent to the main combustion cylinder; an upper intake valve configured to move in the upper non-combustion chamber and to communicate with an intake manifold; and an upper exhaust valve configured to move in the upper non-combustion chamber and to communicate with an exhaust manifold.