US Patent 7743896 Shock absorber having a continuously variable semi-active valve

A shock absorber includes an external valve which controls the damping characteristics of the shock absorber. The external valve controls the flow of fluid between the lower working chamber of the shock absorber and the reservoir chamber and between the upper working chamber of the shock absorber. The damping characteristics are dependent on the amount of current being applied to a solenoid valve which controls the movement of a plunger.