Firstly, the brake-by-wire system is designed to resemble, feel and operate exactly as a conventional vacuum booster or electrohydraulic system would to a driver today. The driver applies pressure to a brake pedal that is linked to a simulator, which in turn provides the feedback it would deliver in a standard system – i.e. the driver will feel that they have applied the brake through the pedal. As it is linked to a Human Machine Interface (HMI), it also has the ability to be designed, adapted and adjusted in many different ways, for example to suit a variety of driving styles, such as comfort, sport, or economy, depending on the customers’ unique specifications.
This pedal / simulator combination has a dedicated sensor that, once the pedal is depressed, is able to gauge the position of the pedal and then feed that information back to the vehicle’s brake control unit (BCU). Once received, the BCU then processes the information and determines the correct level of torque required by each braking corner, which in turn is relayed to dedicated electrohydraulic actuators. These actuators then convert electrical energy sourced from the vehicle’s battery to hydraulic pressure, which is then applied at the determined level. The process ultimately provides a far more efficient way to brake, quickening response times at the same time reducing stopping distances.
All four brake discs are standard components, as are the front calipers, however the rear calipers are electrohydraulic and are therefore controlled by the BCU. Again, the electrical energy from the battery is converted into what is known as clamping force, which is applied in relation to the force target identified by the BCU. This electrohydraulic caliper can also be used where an electronic parking brake function is required, adding additional functionality.