BRAKE BY WIRE
Another significant innovation born during the last 10 years is Brake-By-Wire. The need to guarantee proper braking force to the rear axle, apart from the output torque generated by the electric motors, led to the introduction of another innovation in 2014: Brake-By-Wire (BBW).
Under normal operating conditions, the rear system is no longer activated directly by the driver, but by a high-pressure hydraulic system on the car (much like the ones for suspension and power steering) by means of an electronic vehicle control unit that keeps continuous track of the braking force linked to the two MGUs and the braking distribution imposed by the driver.
The amount of energy to dissipate on the rear axle is equal to the reduced friction, since it is recovered in part by the MGU-K: the result is a less cumbersome and lighter caliper. This is why, in addition to the traditional 6-piston calipers, the maximum allowed by regulation, Brembo supplies several teams with 4-piston calipers to be used at the rear, which responds to their requests for lighter systems.