Tenneco Automotive, Inc.

ASD (Acceleration Sensitive Damping)

Confronting the challenge posed by the long-standing compromise between a soft, comfortable vehicle ride, and precise, sure vehicle handling, Tenneco Automotive found a relatively simple, inexpensive, mechanical solution. The engineers in Monroe, Michigan, developed an Acceleration Sensitive Damping (ASD) shock absorber that utilizes a unique acceleration sensitive mechanical valve. It opens and closes very quickly to adjust to rapid wheel movements on bumps or uneven road surfaces, to maintain a soft ride. However, it remains closed during slower-acceleration body rolls, which maintains stiffness for precise vehicle control, without mushy handling.

The ASD mechanically breaks the compromise between a suspension tuned for crisp handling and body control and one that offers a soft ride. While a number of complex electronic systems are aimed at combining these ride characteristics and overcoming compromises actively, the ASD solution is simple and very cost effective. This damping control can be incorporated into overall ride and suspension systems, however complex, for any type of car or truck. After extensive testing with over 500 prototypes and one-million cycles of high speed bi-frequency tests, Tenneco engineers developed the optimum valve technology to switch oil flow damping from firm to soft ride in 15 milliseconds. ASD impact sensor technology, a genuine engineering innovation, is patented by Tenneco.

Tenneco’s ASD is installed as original equipment on the current Nissan Altima SE and will be launched on the 2002 Lincoln Blackwood luxury pick-up this year. It has been introduced in the automotive aftermarket under the “Reflex” brand and is being reviewed by other car and truck OE’s. Tenneco Monroe is now developing the next generation of ASD technology. The strategy is to coordinate and integrate damping technology into modular and kinetic systems.