Mechanical - Hydraulic layout
The pump of the Haldex Gen IV is an axial piston pump and is capable of providing the unit with the amount of oil flow and pressure needed for optimal performance.
To further increase the performance of the unit an accumulator stores pressurized oil which can be used during intense utilization of the Haldex Gen IV. Between the pump and the accumulator a filter is installed to make sure no particles reach the control valve. The filter is of course maintenance free for low service costs and problem free possession.
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Oil Circuit Schedule |
The valve directs oil to the piston which compresses the disc package. The valve is capable of controlling the pressure, and thereby the transferred torque, between zero and maximum locking torque at any given time. This guarantees high accuracy and optimal performance at any driving condition, independent of vehicle speed and road conditions. |
The valve also guarantees very low opening time, i.e. the time needed to release the pressure and decrease the torque level. This is of great importance for the all wheel drive system to be able to cooperate and not interfere with other systems in the vehicle, e.g. anti-lock brake systems and electronic stability control systems.
The coupling is deactivated when the engine is off, making it possible to tow the vehicle with one axle lifted of the ground. The eLSD (electronic Limited Slip Differential) is an option to the Haldex Gen IV and makes it possible to transfer torque between the left and the right rear wheels. This enhances the traction and the stability of the vehicle. The eLSD acts like an additional feature to the Haldex LSC and utilizes the power pack with pump and accumulator of the Haldex Gen IV. The eLSD has its own clutch package with piston and control valve. The valve is controlled by the ECU on the Haldex Gen IV. This ensures a very light and cost effective way of adding state of the art performance to the already advanced Haldex All Whell Drive system.
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