Description And Operation: Description: Dampers: Notes

The adaptive damping dampers are oil-filled, gas pressurised mono-tube units. To maintain wheel travel, the rear dampers feature an additional external accumulator. The damping force can be adjusted when the vehicle is being driven by an electronically controlled valve. These dampers provide an improved compromise between vehicle control and ride comfort than a typical passive damper. All the dampers have an electrical connector on the end of the piston rod, in the center of the top mount.

In each damper, the damping adjustment is made by a solenoid controlled variable orifice, which opens up a secondary path for oil flow within the damper. When de-energized, the bypass is closed and all the oil flows through the main (firm) valve. When energized, the solenoid moves the armature and control blade. A spring returns the valve to its closed state when de-energized. The control blade incorporates an orifice which slides inside a housing to open up the bypass as required.

With the comfort valve energized and the damper moving into compression, some of the oil flows from the lower portion of the piston through:

• a hollow piston rod,
• a separate soft (comfort) valve,
• a slider housing and orifice,

into the upper portion of the damper, thereby bypassing the main (firm) valve.

In rebound, the oil flows in the opposite direction. The two valves acting in parallel allow the damper to operate in a softer state.

The damper operates between these two boundary conditions.

The solenoid in each damper is operated by a 526 Hz PWM (pulse width modulation) current demand from the Chassis Control Module (CHCM). When fully energized, the control module applies a 1.5A current to operate the damper in the soft setting. When de-energized (0.0A), the damper transfers to the firm setting. The current varies continuously as required to increase and decrease the damping individually in each of the dampers.