The Truth About Active Suspensions

The Truth About Active suspensions also known as adaptive or electronic suspensions are systems that actively adjust the suspension characteristics in real time based on driving conditions. They can be broadly categorized into true active and semi-active or adaptive suspensions. True active suspensions use actuators to directly control wheel movements, while adaptive systems adjust the damping characteristics of the shock absorbers.

Types of Active Suspension

Valve – Actuated

It uses an electronically – controlled valve within the shock absorber to adjust fluid flow, making the suspension firmer or softer.

Electromagnetic

Uses magnetorheological fluid in the shock absorbers, changing its viscosity when a magnetic charge is applied, increasing or decreasing damping.

Air suspension

Uses air pressure to adjust the height and firmness of the vehicle, allowing for independent control at each wheel.

Adaptive Dampers

Adaptive dampers utilize valves or electromagnetic coils to control the flow of fluid and adjust oil pressure, thereby making the ride softer or stiffer. Drivers can choose settings like ‘comfort’ or ‘sport’ to adjust the suspension characteristics.

How it works

Sensors measure the vehicle’s body movements and the ECU uses an algorithm to calculate the vehicle’s motions. The ECU then adjusts the damping characteristics based on the data from the sensors and the vehicle’s main data bus.

Benefits

Adaptive dampers eliminate the trade-off between handling and ride quality by allowing drivers to choose settings that best suit their driving environment.

Active Body Control

Mercedes uses high-pressure hydraulics to pre-stress springs and generate anti-roll forces.

Hydropneumatic

Uses a combination of hydraulic and pneumatic components for active suspension. The purpose of this system is to provide a sensitive, dynamic, and high-capacity suspension that offers superior ride quality on a variety of surfaces. A hydropneumatic system combines the advantages of hydraulic systems and pneumatic systems so that gas absorbs excessive force and liquid in hydraulics directly transfers force. The suspension system usually features both self–leveling, and driver–variable ride height, to provide extra clearance in rough terrain.

This type of suspension for automobiles was inspired by the pneumatic suspension used for aircraft landing gear, which was also partly filled with oil for lubrication and to prevent gas leakage, patented in 1933. The principles illustrated by the successful use of hydropneumatic suspension are now used in a broad range of applications, such as aircraft oleo struts and gas-filled automobile shock absorbers.