Damper (Shock Absorber) Operation

The dampers used on the EDC III system are similar to conventional twin tube dampers, but have two solenoid valves on each damper. These valves provide an additional passage for oil flow in the soft and medium modes of operation.

When the solenoids are de-energized, the damping valves are held closed by spring pressure. This represents the firm setting with oil flowing through the piston and base valves. One of the damping valves is energized for the soft setting and the second valve is energized for the medium setting.

Both valves are never energized simultaneously. Damping can be varied front to rear, but not side to side.






Shown below is a basic gas-charged damper. When the vehicle bounces, the damper travels thru the compression and rebound stages.

The damper, as illustrated, corresponds to the EDC III firm damper setting because the oil transfer uses only mechanical one-way valves.
The EDC III system can provide softer damping rates (soft, medium) by energizing solenoid valves which allow additional oil volume to be transferred.

The EDC III solenoid operation is identical for both soft and medium settings. The soft solenoid has a larger orifice so more oil can pass through the energized solenoid.

Soft Setting = Soft solenoid energized = Maximum oil transfer

Medium Setting = Medium solenoid energized = Moderate oil transfer

Firm Setting = No solenoids energized = No oil transfer