Audi e-tron Gets Electrohydraulic Brake Control System

Car manufacturer Audi claims its e-tron model will be the first electric car fitted with brake-by-wire technology. Depending on the driving situation, the electrohydraulic brake control system decides whether the Audi e-tron prototype will decelerate using the electric motors, the wheel brake, or a combination of the two. 

The Audi e-tron’s recuperation system contributes to up to 30 percent of the electric SUV’s range. The energy recovery can be achieved in three ways: manual coasting recuperation using the shift paddles, automatic coasting recuperation via the predictive efficiency assist, and brake recuperation. The latter is only implemented for a deceleration of more than 0.3 g. In the WLTP test cycle, the electric SUV is able to cover more than 400 kilometres.

To decelerate by more than 0.3 g, a hydraulic piston in the brake module will provide additional pressure, therefore increasing the recuperation by the introduced braking force. According to a statement from Audi, the transition from the motor brake to the pure friction brake is fluid and imperceptible to the driver. When automated emergency braking is performed, there are only 150 milliseconds between the initiation of the deceleration and the presence of maximum brake pressure between the pads and disks. Thanks to this rapid pressure build-up, the braking distance is shortened by up to 20 percent compared with a conventional brake system. The up to 300 kW (402 hp) production version of the vehicle is set to be unveiled in Los Angeles on the 17th September 2018.