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Home >> Volvo >> 2004 >> S40 T-5, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Miscellaneous - Design And Function (544 Body) >> Differential Electronic Module (DEM) (Aw50/51 AWD; M66 AWD; 2005-2010) >> Function >> Hydraulic Function, Overview
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Hydraulic Function, Overview

Fig 1: Identifying Hydraulic Function Overview
GLL107828Courtesy of VOLVO CARS OF NORTH AMERICA.
  1. Cam disc
  2. Rollers
  3. Pressure valves
  4. Pressure limiting valve
  5. Control valve cover
  6. Oil pressure and temperature sensor
  7. Differential electronic module (DEM)
  8. Control valve/axial solenoid
  9. Receiver
  10. Oil screen
  11. Electrical feed pump
  12. Oil filter
  13. Suction valves
  14. Piston pump
  15. Operating piston
  16. Wet plate unit
  17. Bearing
  18. Springs.

The Active On demand Coupling (AOC) can be described as a hydraulic pump.

The basic pressure is generated by the electronic feed pump. This pressurizes the annular pistons with oil so that they are pressed against the cam disc via rollers. The annular piston generates a working pressure which is led to the operating piston via the pressure valves. This pressure creates a fixed connection between the input and output shafts. The maximum pressure is limited by the pressure limiting valve. The difference in speed between the input and output shafts is in proportion to the oil pressure fed to the annular pistons. A large difference between the input and output shafts results in high oil pressure to the annular pistons. If the input and output shafts are at the same speed, the oil pressure to the annular pistons is less. The oil pressure at the multi-plate clutch is regulated by the control valve. The axial solenoid controls the control valve. A closed control valve gives maximum pressure to the multi-plate clutch, resulting in maximum power transmission. An open control valve gives minimum pressure to the multi-plate clutch, resulting in limited power transmission.

The accumulator maintains the basic pressure in the system. The oil filter keeps the fluid clean by filtering dirt and small particles which could damage the system.