Patent ID: 7779974

Claim:
A vehicle suspension spring system for a vehicle wheel station, including: a strut assembly having an hydraulic cylinder with a piston which divides the cylinder volume into a main oil volume and an annular oil volume, said main oil volume communicating via a first oil passage with an associated first accumulator having a main gas volume, said annular oil volume communicating via a second oil passage with an associated second accumulator having an auxiliary gas volume, the oil in each accumulator being separated from the gas by a separator piston or a diaphragm, a third oil passage with an isolating valve which interconnects said first and second oil passages, means for switching the isolating valve between open and closed positions, sensing means for sensing one or more vehicle attitude parameters, said sensing means being connected to a controller which is operable for switching the isolating valve between open and closed positions for altering spring stiffness in response to said sensed vehicle attitude parameter or parameters, wherein the sensing means includes one or more sensors for detecting lateral acceleration of the vehicle, and wherein the sensing means includes means for sensing a speed and a steer angle of the vehicle, the controller including means for inferring a lateral acceleration of the vehicle from said sensed speed and steer angle, and the controller being operable to regulate operation of the isolating valve in response to the sensed vehicle speed and the steer angle.