US Patent 7293780 Vehicle roll control system

A vehicle roll control system for a vehicle has a hydraulic actuator attached to a torsion bar. The system includes first and second pressure control valves fluidly connected in series between a pressure source and a reservoir, and a directional valve fluidly connected between the pressure control valves and the hydraulic actuator. The control valves are actuated to control the fluid pressure within the hydraulic actuator to either extend or compress the hydraulic actuator based on the detection of a predetermined vehicle condition for controlling vehicle roll.