US Patent 8075002 Semi-active suspension system

A suspension system for a wheeled vehicle includes hydraulic actuators associated with each of the vehicle's wheels, a hydraulic pump, a hydraulic accumulator, a compressible hydraulic fluid, and a hydraulic manifold including control valves that open and close to control the hydraulic fluid flow and pressure to each of the hydraulic actuators. The control valves are regulated by a control system including a processor running an algorithm that receives data from switches and sensors providing information regarding the vehicle's state and mode of intended use or storage.