Power Unit

A power unit for a hybrid vehicle is provided with a twin-cylinder reciprocating piston engine, which has two pistons which are guided in two cylinders in tandem arrangement. Two counter-directional crankshafts are connected with the pistons by connecting rods. At least one generator is rotatable co-directionally to the first crankshaft and counter-directionally to the second crankshaft. A camshaft with valve cams are operatively connected with control valves. A flywheel mass element is arranged on the second crankshaft or on a flywheel mass compensating shaft, and a compensating camshaft are provided. The compensating camshaft includes at least one compensating cam element which is operatively connected with a linearly guided compensating mass.