A pneumatic spring system is provided for a motor vehicle with a compressor unit, a storage unit, as well as on-off valves, via which the individual pneumatic springs of the individual wheels are supplied with compressed air. In the area between the compressor unit and the on-off valves, there is provided a vent line that empties out into the atmosphere and that can be locked or cleared by a locking valve. Provision is also made for measures with whose help the air mass flow, emerging via the cleared vent line during a certain time interval, can be limited with respect to an unlimited state in order to prevent any undesirable noise generation during the venting of the system. One measure connects in parallel to a separately lockable main vent line, a separately lockable high-pressure vent line whose clear through flow cross section is smaller than that of the main vent line. Alternatively, a choke element can be provided in the vent line. The through flow cross section of the vent line can be limited with the help of that choke element.
In order to simplify air flow control in a self-contained air supply system, an average control speed is calculated on the basis of a defined movement of the air springs (3, 4) and compared with an optimum control speed. The result of the comparison of the control speeds is used to determine the need for or the excess of an amount of compressed air. There are at least three possibilities for calculating the average control speed.
