At the IAA in Frankfurt in 1999, the carbon-ceramic brake disk had its world premiere. The use of the high-tech material had revolutionized the brake technology: In comparison to the conventional grey cast iron brake disk the carbon-ceramic brake disk weighed round 50 per cent less reducing the unsprung mass by almost 20 kilograms. Further significant advantages are: improved brake response and fading data, high thermal stableness, no hot judder, excellent pedal feel, improved steering behavior, high abrasion resistance and thus longer life time and the advantage of avoiding almost completely brake dust. At first Porsche AG built the carbon-ceramic brake disk in 2001 into the 911 GT2 as series equipment. Since that time also other premium brands use the advantages of this innovative brake technology for more security and comfort. These are for example sports cars and luxury class limousines from Audi, Bentley, Bugatti and Lamborghini.
Dimensioning and Design
The overall car braking system is designed to match a cars layout and take advantage of the ceramic brake disk materials properties. We cover the designing of the brake the construction of the brake disk as well as the selection of the friction layers and the caliper and adjust the brake into the concept of the vehicle. The main parameters determining the braking system design are a cars maximum speed, the time sequence of full brake applications possible to bring a car to a stop from top speed and the mass to be braked, in addition to the axle load distribution and the cars aerodynamics. The purpose of brake disk dimensioning and design is to ensure that a car can be stopped safely under any conceivable driving conditions. Braking system design also needs to ensure that neither the disk itself nor any other component in its direct vicinity is exposed to excessive thermal loads. The optimal cooling vane geometry is determined by numerical methods (Computational Fluid Dynamics) for each car model. The design calculation also takes account of the air pressure building up underneath the car and inside the wheel arch as a function of the cars aerodynamic design and traveling speed.