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Products and solutions, 2001-09-11, 02:00 AM

Adjustable damper systems from Krupp Bilstein

Krupp Bilstein is collaborating with various car manufacturers to develop a whole range of innovative, adjustable damper systems. Three examples - continuously adjustable, amplitude-dependent and position-dependent dampers - will be on display at this year`s IAA show. Added to this is the ADS shock absorber used in the air suspension system for the Mercedes-Benz S-Class. Krupp Bilstein is part of the Systems/Suspensions business unit of ThyssenKrupp Automotive.

The new map-controlled damper from Krupp Bilstein offers continuous and infinite damping force adjustment. This system delivers exactly the right balance of drive dynamics and ride comfort in all conditions. It is based on one software-controlled, electromagnetically regulated bypass valve and an additional fast-acting passive comfort valve on the working piston.

Another innovative damper system from Krupp Bilstein is already on the road in one of the highest quality vehicles in the luxury car class: the ADS (Adaptive Damping System) damper is used in the air suspension of the Mercedes-Benz S-Class. This monotube gas pressure shock absorber with dividing piston features two electrically controlled switching valves which are responsible for the automatic load and speed-oriented damper setting. The valves are installed in a module tube on the side of the shock absorber tube and switch between four possible damper settings in just 60 milliseconds. Rebound and compression can be set independently to "soft" or "hard". Separating the rebound and compression stages using two valves makes it possible to vary damper forces independently of wheel oscillation frequency according to the "Skyhook" principle. The effects of the up and down movement of the wheels on the body are almost completely suppressed, allowing the body to float smoothly over the ground as if suspended on a "Skyhook".

A comparatively low-cost solution from Bilstein for enhanced safety and ride comfort is the amplitude-dependent damper. Suitable for standard monotube and twin-tube shocks, the system switches automatically between hard and soft settings in response to wheel and body movements. A bypass in the working piston is designed to open when piston movements - amplitudes - are minor and close automatically when stroke length increases. The passive bypass is controlled only by the flow and pressure conditions in the shock absorber tube. The amplitude-dependent damper is also particularly suitable for vehicles which, due to their design, tend to roll heavily, which in the past was countered with comparatively hard damping. The amplitude-dependent damper offers the necessary roll stabilization, greater comfort and a quieter, smoother drive.

Bilstein developed the position-dependent damper for vehicles which are frequently driven with heavy payloads, such as minivans or station wagons. For example, the new Mercedes-Benz Vaneo, which DaimlerChrysler will be unveiling at this year`s IAA show, is fitted with these shocks. They are designed to develop high damping forces when loads are high, and a softer, more comfortable setting for normal loads. This flexibility is provided by a groove in the damper tube which acts as a bypass for the hydraulic oil. As long as the working piston is operating in the bypass zone, some of the oil can flow past the piston to provide soft damping. But if the piston is lowered sharply, for example through heavy loading, it moves out of this bypass zone and damping is stiffer because the oil is only able to flow through the small opening offered by the piston valve. As there is wide design latitude for shape and position of the bypass, Bilstein can consult with carmakers to provide the ideal version for each vehicle type.

For further information contact:
ThyssenKrupp AG
Trade Press
Bernd Overmaat
Telephon: +49 (0)211 824-36012
e-mail overmaat@tk.thyssenkrupp.com

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