A volume-controlled four-stroke reciprocating internal combustion engine comprising:
- a first cylinder, in which a first piston operatively connected to a crankshaft via a first connecting rod is disposed so as to be displaceable in a reciprocating motion;
- a second cylinder, in which a second piston operatively connected to the crankshaft via a second connecting rod is disposed so as to be displaceable in a reciprocating motion;
- a fresh air tract for the second cylinder, in which an expansion/compression machine is disposed in a direction of flow of fresh air before a gas exchange inlet valve of the second cylinder;
- and
- an exhaust tract for the second cylinder, wherein the expansion/compression machine is the first cylinder.