Basic Function

The unique design of the Haldex Gen IV compromises four functional parts:

• Hydraulic power pack with electrical motor and accumulator
  
• Wet multi-plate clutch
  
• Controllable pressure reducing valve.
  
• Electrical control unit (ECU).

The front and the rear axle of the car is connected via the wet multi-plate clutch which makes it possible to vary the torque distribution between the two axles. As the function of the Haldex Gen IV is independent of the differential speed between the front and the rear axle full lockingtorque, if needed, is available at any given time and speed.

When starting the vehicle the electrical pump in the Haldex Gen IV is started, swiftly providing the system with pressurized oil and thereby making the system ready for operation. The control valve sets the pressure to the piston which in turn compresses the disc package. The level of pressure set depends on the torque level needed which in turn depends on the driving situation. In traction/high slip conditions, a high pressure is delivered: in tight curves (i.e. parking), or at high speeds - a much lower pressure is provided.

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