Patent ID: 7036835

Claim:
A suspension system for a vehicle having a wheel contacting a surface under the vehicle and a suspension link suspending the wheel from the vehicle and allowing relative movement of the wheel and the vehicle, said suspension system comprising: a compressible fluid; a suspension strut adapted to couple the suspension link and the vehicle; a hydraulic cavity at least partially defined by said suspension strut and adapted to contain a portion of said compressible fluid and to cooperate with said compressible fluid to supply a suspending spring force that biases the wheel toward the surface; a reservoir adapted to contain a portion of said compressible fluid; and a volume modulator coupled to said hydraulic cavity and said reservoir and adapted to selectively push said compressible fluid into said hydraulic cavity and vent said compressible fluid from said hydraulic cavity, thereby actively modulating said suspending spring force, wherein said volume modulator defines a modulator cavity and includes a modulator piston adapted to cycle through a compression stroke and an expansion stroke within said modulator cavity, and includes a valve system adapted to selectively restrict the passage of said compressible fluid between said hydraulic cavity and said modulator cavity or restrict the passage of said compressible fluid between said reservoir and said modulator cavity, said valve system including a rotary valve coupled between said modulator cavity, said hydraulic cavity, and said reservoir, said rotary valve being adapted to selectively rotate to a first position thereby restricting the passage of said compressible fluid between said hydraulic cavity and said modulator cavity and allowing the passage of said compressible fluid between said reservoir and said modulator cavity.