Car maker Audi now says its engineers are working on a prototype called eROT, in which electromechanical rotary dampers replace the hydraulic dampers used now, promising a more comfortable ride.

Stefan Knirsch, board member for Technical Development at Audi, says that the principle behind eROT is that every pothole, bump, and curve induces kinetic energy in the car. Current dampers absorb that energy, which is then lost in the form of heat. With Audi’s electromechanical damper system in the 48-volt electrical system, the energy is put to use and presents new possibilities for adjusting the suspension.

The eROT damping system is capable of producing energy. Because it is an actively controlled suspension, it adapts to irregularities in the road surface as well as to the driver’s driving style. Functional scope is increased by a damper characteristic that is almost freely definable via internal software. It eliminates the mutual dependence of the rebound and compression strokes that sometimes limits conventional hydraulic dampers.

With eROT, Audi says it can configure the compression stroke to be comfortable without compromising the taut damping of the rebound stroke. Due to the damper system’s geometry, the horizontally arranged electric motors in the rear axle area replace the upright telescopic shock absorbers, allowing for additional space in the luggage compartment.

Apart from the programmable damper characteristic, the eROT system can convert the kinetic energy during compression and rebound into electricity. To do this, a lever arm absorbs the motion of the wheel carrier. The lever arm transmits this force via a series of gears to an electric motor, which then converts it into electricity. The recuperation output is 100 to 150 watts on average during testing on German roads – from 3 watts on a freshly paved freeway to 613 watts on a rough secondary road. Under customer driving conditions, this corresponds to a CO₂ savings of up to three grams per kilometer, or 4.8 grams per mile

Audi says that it intends to put eROT into production cars in the future, but hasn’t specified a date.