Electric Brake Systems
Since the time when antilock systems and traction assistants were introduced, the electronic control of the brake force on individual wheels has become quite normal (Chapter 4.4.7).
Since these control systems generally require electrical actuators in order to transform electronic control signals, it would make sense designing the entire brake system electrically. The brake pedal then only serves as a signaling device.
Advantages of a purely electrical brake system are:
Absence of all hydraulic or pneumatic components,
Absence of brake force transmission since the brake force is only created on the wheel.
Disadvantages of a purely electrical brake system:
No emergency braking function when electric control fails,
High additional load of the electrical system of the vehicle in order to create a braking force,
Considerably higher space required for the wheel brakes,
Considerably higher weight of the wheel brakes.
Since electric components have approx. sixty-times the power to weight and approx. thirty-times power to volume compared to hydraulic components, the generation of the necessary braking force remains a problem. The figure shows the prototype of an electric disk brake.
In order to solve the problem related to brake force creation, drum brakes can be used as an alternative due to their high self-energization. Drum brakes on the other hand have essential disadvantages associated with their operating behavior.
In the medium term future, the use of purely electrical braking systems hence remains doubtful. Semi-electronic braking systems on the other hand have a higher probability of seeing application, since here the wheel brakes are actuated hydraulically while the foot pedal serves only as a signal generating device. The generation and control of hydraulic pressure takes place electrically or electronically.