VANOS Inlet/Exhaust

VANOS inlet/exhaust
A controlled VANOS unit is installed on the M52 with MS42 for inlet and exhaust. It is activated by means of an electromagnetically operated 4/3-way valve.

The required position of the inlet and exhaust camshafts is calculated from the engine speed and load signal depending on the intake air and engine temperature and the VANOS unit is controlled accordingly by the engine control unit. The inlet and exhaust camshafts can be variably controlled within their maximum adjustment range, i.e. any arbitrary positions are possible corresponding to the specified values of the engine control unit. When the relevant optimum camshaft position is reached, the solenoid valves maintain a constant oil volume in the adjustment cylinder on both sides of the chamber so that the camshafts remain in the corresponding positions.

When the engine starts up, the inlet camshaft is in its end position, i.e. it is initially in the retard position. During engine start, the exhaust camshaft is held in the advance position by means of a spring.