TECH NEWS – Stuttgart – Bosch’s new brake-by-wire hydraulic braking system was tested over six days, over more than 3,300 kilometers and across different climate zones, all the way to the Arctic Circle. The company’s development team tested the new technology in road traffic for the first time. The essence of the brake-by-wire braking system is that the solution completely eliminates the mechanical connection between the brake pedal and the braking system.

The system transmits the braking commands given by the driver to the brake-by-wire braking system as purely electrical signals via redundant signal cables. Bosch offers a robust and effective solution for this innovative approach with two independent hydraulic brake actuators – an electronically controlled brake actuator and an electronic stability program (ESP®). Today’s braking systems still ensure safe stopping – even in the event of a failure – through a mechanical connection to the brake pedal. However, the new Bosch brake-by-wire solution no longer has a mechanical connection to the brake pedal.

Bosch is one of the leading companies in the field of braking and steering systems, working on innovative by-wire solutions. This includes this electronically controlled hydraulic brake system (brake-by-wire), which is scheduled to be launched on the market in the fall of 2025. In addition to the hydraulic solution, Bosch is also developing a purely electromechanical system. The group expects that brake-by-wire braking systems will be available in more than 5.5 million vehicles worldwide by 2030.

Advantages of the Bosch brake-by-wire system

Innovative design freedom: Since there is no mechanical connection, it is no longer necessary to mount the brake system components on the vehicle firewall; instead, they can be arranged in the most optimal way in terms of crash safety, noise and vibration levels, and production technology. The flexible choice of installation location for the brake actuators also means that different components are not required for right-hand and left-hand drive vehicles. By-wire technology results in significantly shorter brake pedal travel, which also enables new pedal concepts, which leaves more space for interior design. Bosch’s hydraulic brake-by-wire solution is based on proven brake system technology and consists of a combination of a by-wire brake actuator and the electronic stability program (ESP®). Its compact design saves installation space and reduces the weight of the brake system at the same time. Since both the by-wire brake actuator and ESP® operate on different channels of the redundant electrical system, they can generate the necessary brake pressure on all four wheel calipers independently in the event of a fault. The Bosch solution is also suitable for highly automated vehicles and fully meets the safety requirements of the brake system.

Successful long-term test with valuable data for further development

The electronically controlled (brake-by-wire) system is being developed at Bosch’s headquarters in Abstatt, near Heilbronn, Germany. The team’s long-term test route led from southwest Germany via Hamburg, Copenhagen and Stockholm – with a short detour to the Arctic Circle – to Bosch’s winter test center in northern Sweden. Based on its comprehensive safety concept, Bosch has applied for and received road approval for its test vehicle in several countries. “The entire team worked on this test with incredible motivation, and we are very proud of the result. Our hydraulic brake-by-wire system worked perfectly on the road. With our first long-term test, we have convincingly demonstrated that a real brake-by-wire system can be successfully and safely transferred from the test track to the road,” emphasized Hagen Kuckert, project manager for the by-wire brake actuator at Bosch in Abstatt. “Thousands of braking operations were performed during the test. This allowed us to collect important data on the behavior of the brake system in a wide variety of driving situations, which we were then able to compare with our previous simulations. We can use all this in our future development work to further optimize our hydraulic by-wire brake system.”