Audi has announced that it is working on a prototype suspension system called “eROT,” in which electromechanical rotary dampers replace conventional hydraulic dampers.
“Every pothole, every bump, every curve induces kinetic energy in the car. Today’s dampers absorb this energy, which is lost in the form of heat,” said Dr.-Ing. Stefan Knirsch, board member for technical development at Audi AG. “With the new electromechanical damper system in the 48-volt electrical system, we put this energy to use. It also presents us and our customers with entirely new possibilities for adjusting the suspension.”
The eROT system enables the conversion of kinetic energy created 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 converts it into electricity. The recuperation output is 100 to 150w on average during testing on German roads – from 3w on a freshly paved freeway to 613w on a rough secondary road. Under customer driving conditions, this corresponds to a CO2 savings of up to 3g/km (4.8g/mi).
The new eROT technology is based on a 48v electrical system. As currently configured, its lithium-ion battery offers an energy capacity of 0.5kWh and peak output of 13kW. A DC converter connects the 48v electrical subsystem to the 12v primary electrical system, which includes a high-efficiency, enhanced output generator.
Audi states that initial test results for the eROT technology have been promising, intimating that its use in future Audi production models is ‘certainly plausible’. A prerequisite for this is the 48v electrical system, which is a central component of Audi’s electrification strategy. In the next version planned for 2017, the 48v system will serve as the primary electrical system in a new Audi model and feed a high-performance mild hybrid drive. In its current state, Audi states that the system will offer end users potential fuel savings of up to 0.7l per 100km.