VANOS Control

As with the Bosch DME Systems, the MS41.1 system controls the operation of the VANOS solenoid. The MS41.1 Control Module follows the same parameters as the M3.3.1 system. Engine RPM, load and temperature are used to determine VANOS activation.

The operation of the VANOS solenoid is monitored in accordance with the OBD II requirements for emission control. The MS41.1 Control Module monitors the final stage output control and the signal from the camshaft position sensor for VANOS operation.







Retarded Timing: In the normal or off position, the spool valve in the piston housing is held by spring pressure directing the engine oil to the back side of the piston. This pulls the attached helical gear cup forward and maintains the late valve timing position.







Advanced Timing: When the MS 41.1 control module provides a ground to the solenoid, the spool valve pushes against the spring pressure diverting the pressurized engine oil to the front side of the piston. This pushes the helical gear cup further into the matched helical camshaft secondary gear drive.

The angled teeth of the helical gears cause the pushing movement of the helical cup to be converted into a rotational movement. This rotational movement is added to the turning of the camshaft and causes the intake camshaft to "advance" 12.5°.