Abstract: A method and system are set forth for leveling a vehicle chassis supported on air springs. The system and method include a position switch at each air spring which is adapted to generate a signal when the spring is compressed to or beyond a desired length representing the desired level for the vehicle chassis. Based upon the duration of the signal over a time interval a duty cycle for the spring is established. If the duty cycle is below a desired valve or range of valves this indicates the chassis is too high and the system incrementally deflates the spring. If the duty cycle is above the desired valve or range of valves this indicates the chassis is too low and the spring is incremetally deflated. Accordingly, leveling can take place when the vehicle is in motion.

Abstract: A position switch is set forth which is adapted to generate a signal whenever two masses, such as a vehicle sprung and unsprung mass, are at or nearer than a desired spacing. The switch includes a grounded, conical, coiled spring attached to one mass, and an electrically charged plate secured to the other mass. The spring has a relaxed length to lie adjacent the plate when the masses are at the desired spacing. When the masses are brought together the spring contacts the plate, is compressed, and the plate is grounded generating a current signal indicating that the masses are at or nearer than the desired spacing.

Abstract: A vehicle suspension system in which a computer controls damping and spring forces to optimize ride and handling characteristics under a wide range of driving conditions. A controllable shock absorber connected between the wheel and frame of the vehicle includes a hydraulic sensor which provides signals to the computer which are representative of the position of the piston within the shock absorber. The computer utilizes these position signals to control compression and rebound hydraulic pressure regulators by continuously computing, utilizing programmed algorithms, compression and rebound damping forces that will yield the desired ride and handling characteristics. An air spring may be connected with the shock absorber for compression and rebound along the same axis. Pressure sensors and air pressure inlet and outlet valves are connected to the computer for adjusting the pressure within the air spring to provide the desired spring rate.