Every bump a volt with Audi's eROT suspension

A new system under development by Audi promises to enable further improvements in fuel efficiency in its hybrid vehicles by using the vibrations normally absorbed by a car’s suspension system to generate electrical energy. The system, called eROT (electromechanical rotary dampers), will also make the car’s ride more comfortable, the company claims.

The system is intended to replace the hydraulic dampers that have been used in suspension systems for many years. In these, the up-and-down motion of the wheels as they pass over bumps in the road is simply converted into heat as the increasing pressure in the hydraulic cylinders warms up the working fluid.

The eROT system, by contrast, is an active electrical system linked to the car’s 48-volt electrical network, in the same way as the regenerative function of the braking sytem. It absorbs suspension movement via a lever fixed to the wheel carrier mechanism at one end, and to a series of gears at the other. When the lever moves, its motion is transferred, via the gears, to an electric motor configured as a dynamo and connected to the car’s lithium ion battery.