Adaptive Shock Absorbers

The adaptive shock absorbers are nitrogen gas and oil filled monotube units. The adaptive shock absorbers are continuously variable, which allows the damping force to be electrically adjusted when the vehicle is being driven. The adaptive shock absorbers provide the optimum compromise between vehicle control and ride comfort.

The adaptive shock absorbers have an electrical connector on the end of the piston rod, in the center of the top mount.

In each adaptive shock absorber, the damping adjustment is achieved by a variable orifice operated by a solenoid. The orifice is used to open up alternative paths to allow oil-flow within the adaptive shock absorber. When de-energized the bypass is closed and all the oil flows through the main (firm) piston. When energized the solenoid moves an armature and control blade, which work against a spring. The control blade incorporates an orifice which slides inside a sintered housing to open up the bypass as required. When the adaptive shock absorber is compressed the oil flows from the lower portion of the adaptive shock absorber then through a hollow piston rod, which is a separate soft (comfort) valve. The oil then flows through the slider housing and orifice and into the upper portion of the adaptive shock absorber, thereby bypassing the main (firm) valve. In rebound the oil flows in the opposite direction.

In the firm setting oil flows through the main (firm) valve only, although when the bypass is opened by variable amounts, the oil flows through both valves to provide a pressure balance. When fully energized the solenoid moves the armature and therefore the slider to the maximum extension and opens the orifice completely. The adaptive shock absorber operates continuously between these two boundary conditions.

The solenoid in each adaptive shock absorber is operated by a 526 Hz Pulse Width Modulation (PWM) signal from the Chassis Control Module (CHCM). The CHCM controls the PWM duty ratio to provide 1.5A to operate the adaptive shock absorber in the soft setting. When de-energized (0.0A) the adaptive shock absorber is in the firm setting. The current varies continuously as required to increase and decrease the damping individually in each of the adaptive shock absorbers.

Sectioned Views of Shock Absorber Operating States 

Courtesy of JAGUAR LAND ROVER NORTH AMERICA, LLC