An active vehicle suspension includes a strut comprising a piston working in a cylinder and movable to compensate for unexpected road inputs to the suspension and for inputs generated by the driver, such an inertial force introduced by braking or cornering. At times when the piston is being moved by the road and driver inputs to compress the strut excess hydraulic fluid is fed from the strut to an accumulator where it is temporarily stored at high pressure and later released back to the strut when it is desired to increase the length of strut. Thus some, and sometimes all, of the energy needed to extend the strut can be supplied by the accumulator rather than a pump. This save energy. The piston has unequal areas and a system of spool valves is provided to control the flow of fluid between the strut, accumulator, and pump.