Patent ID: 6991239

Claim:
A height control system for a vehicle having a predetermined ride height comprising a suspension having a pair of arm assemblies for carrying an axle supporting ground engaging wheels, each of the arm assemblies having an arm with one portion pivotally mounted to the vehicle and an air spring positioned between the vehicle and another portion of the arm to resist the pivotal movement of the arm toward the vehicle, and an air system for at least supplying pressurized air to the air spring, the height control system comprising: a valve to selectively fluidly connect the air spring to either the air system or the atmosphere for selectively introducing or exhausting air from the air spring to effect the relative movement of the arm and the vehicle to adjust the vehicle ride height; a light sensor coupled to the arm that senses rotational movement of the arm and sends an output signal related to the amount of rotational movement of the arm said light sensor including an optical bridge and a light emitter that projects light onto the optical bridge and the optical bridge generates the output signal which corresponds to the intensity of the projected light across the optical bridge; a wall with a diffraction slit disposed between the light source and the optical bridge so that the light projected from the light source passes through the diffraction slit and is diffracted prior to reaching the optical bridge; and a controller coupled to the transducer and to the valve wherein the controller receives the transducer output signal and selectively actuates the valve in response to the value of the output signal to operate the height control system between an off mode, where the air spring is fluidly disconnected from the air system and from atmosphere, a fill mode, where the valve fluidly connects the air spring to the air system, and an exhaust mode, where the valve fluidly connects the air spring to atmosphere, to maintain the vehicle at the predetermined ride height.