Vehicle roll control system

A roll control system for a vehicle having a pair of front wheels each rotatable on a front axle and a pair of rear wheels each rotatable on a rear axle, the system comprising a front torsion bar;

• a front first hydraulic actuator attached to one end of the front torsion bar and connectable to the front axle;
• a front second hydraulic actuator attached to the other end of the front torsion bar and connectable to the front axle;
• a rear torsion bar;
• a rear first hydraulic actuator attached to one end of the rear torsion bar and connectable to the rear axle;
• a rear second hydraulic actuator attached to the other end of the front torsion bar and connectable to the rear axle;
• and a controller connected to the hydraulic actuators and controlling the operation thereof on detection of a predetermined vehicle condition;
• wherein each hydraulic actuator comprises a housing, a piston making a sealing sliding fit inside the housing to define a first fluid chamber and a second fluid chamber, and a piston rod connected to the piston and extending through the second fluid chamber and out of the housing;
• wherein the controller comprises a source of fluid pressure, a fluid reservoir, a pressure control valve fluidly connected between the pressure source and the reservoir, and a plurality of pressure relief valves each having positions to selectively fluidly connect the fluid chambers of the hydraulic actuators to one of the pressure source or the fluid reservoir;
• wherein the pressure relief valves are positioned on detection of the predetermined vehicle condition to apply a fluid pressure to the first fluid chamber of the first front hydraulic actuator and to the second fluid chamber of the second front hydraulic actuator.