The brakes transfer the forces applied to the brake pedal, either regulated or to achieve the maximum deceleration, depending on the driving situation. Thereby, the vehicle should stay on track and always remain
steerable. It's function must be guaranteed, also then, when the high temperature between the lining/pad and the drum/disc reaches between 700 - 800°C (with non-ceramic material). Basically, when braking, kinetic
energy is converted into thermal energy. This conversion is always distinctly more effective and quicker than the other way round (heat-> movement) in the combustion engine. Thus, a vehicle can always brake better
than it can accelerate.
|Legal minimum delay: 5,8 m/s²|
The foot brake generates or regulates the pedal-pressure, which is then hydraulically, thus evenly distributed to the individual brake cylinders, which provide for friction between the disc/drum, which turns with the
wheel, and the static friction surfaces linked to the suspension. In motor cars and light delivery vehicles, most of the force is provided by pressing the brake pedal with the foot. The pressure to the linings/pads follows
hydraucally. In larger trucks and busses, the lining/pad pressure is applied pneumatically. In this case, one can only regulate by using the brake pedal. One speaks of power-assisted brakes.
In the case of the hand brake, the situation is more complicated. Here, the force can be applied either by hand or by foot. With newer hand brakes, the force can also be delivered by an electric motor or hydraulic pump.
With the power-assisted brake, the handbrake is operated either pneumatically or - more often - by a strong spring on the brake linings, which is pressed together by compressed-air.
Since 1978 the electronics have found their way into the brake systems. In the beginning, it released the individual wheel-brakes
for a short time when too much slip
threatened. Then an intervention was developed which, under certain circumstances, increased the brake power more than the force applied by the pedal activity. Relatively new, (2006) are interventions whereby the
vehicle brakes, without the driver doing anything at all, then however, only when a full braking is necessary to avoid an, otherwise certain, rear-end collision. 09/11
|Cycle of a braking application (without ABS intervention)|
Detect the danger|
|Reaction time, till the pedal is slamed|
|Pressure in the system increases, max. delay reached|
|Speed will be reduced significantly|
|Pedal is released|