Enhanced convenience

due to air springs

Innovative air spring technology for public railway transport

The Chinese Transrapid, France's record-breaking train, the TGV or its German equivalent, the ICE 3 – ContiTech's air spring systems provide maximum convenience at extreme speeds worldwide. In the Transrapid, for example, ContiTech air springs provide the elastic mounting of the passenger compartment and, in this way, make a considerable contribution towards convenience and safety.

Furthermore, ContiTech air springs set standards worldwide for the secondary suspension of modern passenger train carriages. Positioned between the bogie and superstructure, they largely decouple the superstructure from irregularities of the tracks and allow the bogie to turn when negotiating bends. Participants of the TGV's record breaking trip in April 2007 were able to experience the suspension convenience of ContiTech air spring systems at 574 km/h.

The advantage of the pneumatic suspension of passenger train carriages in terms of comfort is that their suspension properties can be adjusted according to the load. The level is currently controlled by pneumatic valves which are operated by means of a system of levers. ContiTech has integrated a non-contact height and pressure sensor in an air spring. It provides the technical basis for the use of electronically controlled air spring systems with electrically operated valves.

Conventional level control causes greater air losses because it is permanently active and adjusts dynamic changes in level also while the vehicle is in motion. To reduce this effect, the mechanically operated pneumatic valves have a "passive" zone around their neutral position in which air is neither applied to nor removed from the air spring. The electronic control reduces the number of adjustment processes considerably because it readjusts the level only if the load changes due to passengers getting on or off. The integrated ultrasonic sensor transmits the actual values of the spring height and the bellows pressure to the electronic control unit, which actuates the solenoid valves to apply air to or remove air from the system. This allows the vehicle level to be adjusted to different platform heights.

Furthermore, information is gained for the load-dependent activation of the brakes by the ultrasonic sensor. The ultrasonic sensor is almost ready for series production. It has already passed vehicle tests at numerous manufacturers for usage in commercial vehicles.

This will make it possible for future rail vehicles to benefit from the advantages that road vehicles have profited from for so long:

  • Low air loss
  • Precise vehicle level adjustment
  • Adjustment of variable target level

Innovative air spring technology for busses

The new Citaro LE interurban bus – a cross between a low-entry city bus and a high-entry interurban bus – of the Daimler subsidiary EVOBus has hit the headlines due to its handling characteristics. The combination of independent wheel suspension at the front, coach axle at the rear and a considerable increase in the air volume of the suspension at both axles contributes towards very convenient straight-line driving.

Customized ContiTech air spring systems play a significant role here. The use of plastic instead of metal for the beveled plate makes the air spring system corrosion-proof. In combination with a lighter piston, the weight of the system was able to be reduced by more than 20 %. Valuable seconds can be saved by the new system when lowering the vehicle at bus stops. This gives the Citaro a crucial competitive edge.

This successful cooperation was based on the introduction of a modular system for air spring systems, which allows the product to be customized to meet the different requirements of pneumatic suspensions in city busses, interurban busses and coaches.

Innovative Luftfedertechnologie

ALSTOM Transport / P.Sautelet

Innovative Luftfedertechnologie