System for the rotation of a camshaft relative to a crankshaft of an internal combustion engine

A system to rotate a cam relative to a crankshaft of an internal combustion engine, comprising

• a drive pulley (4) that is connected to the crankshaft of the engine through a chain, belt or sprocket drive (5),
• an electric motor (7) that transfers torque to the camshaft (3) of the engine,
• the electric motor (7) is attached to one end (8) of the camshaft (3) directly or through an intermediate drive mechanism, and acts as a primary drive unit of the camshaft (3) and as a servomechanism to adjust and maintain a controlled camshaft angular shift,
• the drive pulley (4) is fastened to and moves about an other end (9) of the camshaft (3) within a defined range of rotation and acts as a forced synchronization instrument for the electric motor (7) within the range of rotation as well as a secondary drive unit for the camshaft (3),
• wherein the electric motor (7) is connected to an RPM controller (10) with which an RPM of the electric motor (7) is synchronized and changed with respect to an RPM of the drive pulley (4) to adjust and maintain a controlled camshaft angular shift.