Component description for the adjustable camshaft timing solenoid - GF05.20-P-2100CY

ENGINE 272.911 in MODEL 204.0 

ENGINE 272.921 in MODEL 204.0 /2 

ENGINE 272.947 in MODEL 204.0 /2 

ENGINE 272.948 in MODEL 204.0 /2 

ENGINE 272.961 in MODEL 204.0 /2 

ENGINE 272.971 in MODEL 204.0 /2 

Location 

The solenoids are located in front of the respective camshaft.

Task 

Solenoid actuate the control plungers for the vane-cell adjuster which in turn adjust the camshafts.

Design 

Solenoids are designed as proportional solenoids which means travel of the anchor and thus the location of the control plunger in the vane-cell adjuster is dependent on the current strength in the coil. The coil resistance at interior temperature is approx. 7.5 Ω.

Function 

Solenoids are actuated at the ground end by the ME-SFI [ME] control unit (N3/10) by means of a PWM signal (pulse width modulated signal). The frequency of the PWM signal is 150 Hz. Voltage is supplied to the solenoid is via "circuit 87 M". The control plunger for the vane-cell adjuster is actuated via the performance map-dependent duty cycle of the PWM signal. In order to achieve rapid adjusting of camshafts (about 0.5 s) the duty cycle of 100% (maximum current strength) is output. A hold-in winding voltage is then set using a duty cycle (lower current strength).

Depending on the position of the control plungers, more or less pressure oil flows from the hollow camshafts into the oil galleries of the vane-cell adjusters. This is achieved by bore holes located at various points on the control plungers and by oil ducts in the vane cell adjusters. The vane-cell adjusters adjust the camshafts according to their filling with pressure oil. If the solenoids are no longer actuated, a mechanical reset, counter to the direction of rotation, takes place.

The camshaft adjustment range is mechanically restricted by the shape of the vane-cell adjuster.

The following positions of the control plunger are possible:

• Fill oil galleries 

  Pressure oil flows from the hollow camshafts into the vane-cell adjuster. The camshafts adjust to the respective direction of rotation. Adjust the intake camshafts to "advanced". The exhaust camshafts adjust, due to their reverse direction of rotation, to "retarded".

• Close oil galleries 

  A camshaft Hall sensor per camshaft detects the camshaft positions. Once the necessary adjustment is obtained, the respective solenoid is actuated so that the oil galleries in the vane-cell adjusters are closed.

• Empty oil galleries 

  The camshafts mechanically adjust counter to their direction of rotation.