Patent ID: 7357395

Claim:
A device for controlling suspension performance in a vehicle having variable loads on an axle, the vehicle including a level control system and a hydropneumatic suspension apparatus between unsprung and sprung masses, the device comprising: at least one double-acting hydraulic cylinder having a cylinder chamber and a toroid chamber; a pump; a cylinder chamber inlet line connecting the pump to the cylinder chamber; a toroid chamber inlet line connecting the pump to the toroid chamber; a cylinder chamber outlet line; two 2/2 port directional control valves configured to regulate the level control system and disposed in the cylinder chamber inlet line and the cylinder chamber outlet line, respectively; a pilot valve disposed in the toroid chamber inlet line and dependent on a pressure level in the cylinder chamber inlet line; and a two-stage pressure control valve disposed downstream of the pilot valve and configured to regulate a toroid pressure level in the toroid chamber as a function of a cylinder pressure level in the cylinder chamber so that the toroid pressure is increased when the cylinder pressure is low.