Vehicle Dynamic Suspension: Notes

Fig 1: Identifying Vehicle Dynamic Suspension

Courtesy of JAGUAR CARS, INC.

The vehicle dynamic suspension is a passive air suspension system providing vehicle levelling independent of load.

The system also improves the drag coefficiency by automatically lowering the vehicle for high speed driving.

When driving at high speeds, the air suspension system will lower the vehicle to improve aerodynamics and vehicle stability. The suspension will automatically return the vehicle to the normal ride height when the vehicle slows.

NOTE: Speed lowering is disabled when towing. Only Jaguar approved towing equipment will inhibit this feature.

The air suspension system ensures that the vehicle is always at the correct ride height for varying load conditions.

The air suspension system automatically adjusts the amount of air in the air springs to level the vehicle. Air is supplied either from an air reservoir or a compressor. The compressor will run periodically to fill the air reservoir.

The air suspension module (ASM) controls the operation of the solenoids in the valve block. The front air springs are operated as a pair, the rear air springs are operated independently of each other. The ASM adjusts one axle at a time, for example, when lifting the vehicle the rear axle is controlled first; when lowering the vehicle the front axle is controlled first. This reduces headlamp glare during leveling operations.

The ASM uses two different filter rates. When stationery, a 'fast' filter allows the system to react quickly to payload changes. While driving a 'slow' filter allows for compensation of the fuel level change but does not react to road inputs for example pot holes and speed bumps.