Courtesy Bosch
Ever since it premiered the servo brake in 1927, Bosch has been continuously tweaking the way brakes work. Bosch engineers reached further milestones with the debuts of the antilock braking system (ABS) and the electronic stability program (ESP). Now the next big leap forward is about to be launched – brake-by-wire. But how well will the system work in snow, ice, and temperatures down to minus 25 celsius? Just a few miles from the Arctic Circle, Bosch engineers put it through its paces.
Hagen Kuckert project leader for Brake by Wire from Bosch says: “While traditional brake systems feature a mechanical connection between brake pedal and brake system, our brake-by-wire system does away with this completely. If drivers want to brake, this intention is transmitted as a purely electrical signal through redundant – completely discrete, in other words – signal lines.” For this radically new approach, Bosch offers a robust and efficient solution comprising two hydraulic brake actuators – the by-wire brake actuator and an ESP. For Kuckert, there is absolutely no doubt that brake-by-wire is the brake system of the future: “As early as 2030, we forecast that more than 5.5 million vehicles worldwide will be equipped with brake-by-wire.”
Lighter, safer, more flexible: the advantages of brake-by-wire
The chief advantage of brake-by-wire is that installation is more flexible, creating new possibilities for the interior design of vehicles. As there is no longer any mechanical connection, brake system components no longer have to be mounted on the vehicle’s firewall. Instead, the components can be installed where they make most sense in terms of crash safety, NVH, and manufacturing.
Its slim design means less space is needed for installation, and that the braking system is lighter. Compared with conventional braking systems featuring redundancy, it can be up to 25 per cent lighter. As the by-wire brake actuator and the ESP are assigned to separate channels of the redundant electrical system, they can build up brake pressure on all four wheels independently of each other in the event of a system failure. This makes the Bosch solution suitable for highly automated vehicles as well, as it meets the safety requirements for such vehicles’ brake systems.
On top of that, Bosch is once again helping to avoid injuries in the case of accidents. Because of the crash-optimised way all the brake components are installed, and because of the new pedal designs without any mechanical connection to the braking system, foot injuries in particular can be reduced.
And how does brake-by-wire feel in practice? “There’s no difference in braking experience and safety. And that’s just what drivers want,” Kuckert says. But is that really the case in everyday conditions and on country roads? To answer that question, it was subjected to an endurance test almost exactly three years after the start of the project.
This was where Uwe Ongert came in. One of the “midwives” of the brake-by-wire system, the systems integrator has been on the project since it began. He takes things that work in theory and puts them into practice. “Leaving the proving ground for Sweden was definitely the highlight of this project for me,” Ongert says. At the end of 2024, he and a small team set off to Sweden from their southern German base in Abstatt. It was a 3,300-kilometre drive on roads of different kinds: country roads, freeways, urban roads – with a short detour to the Arctic Circle. After six days, the vehicle reached Vaitoudden, the site of the Bosch winter test centre near Arjeplog, northern Sweden.
Customer feedback – essential for a successful market launch
Up near the Arctic Circle, the conditions are perfect for putting brake-by-wire through its paces. “During the winter season, we alternate between two weeks in Sweden and one in Abstatt. The days are long and intense, but the close collaboration between the Bosch team and customers means we make huge progress in very little time,” Ongert says. His enthusiasm for the system, his job, and the test drives is palpable. “The proof of the pudding is in the eating. That’s why we’re so glad that our customers can try out the system for themselves here in Sweden. And in its turn, their feedback finds its way straight back into the development process,” the systems integrator says.
Bringing theory and practice together: a strong team for the braking system of the future.
At all events, Hagen Kuckert and Uwe Ongert agree that brake-by-wire is an important component for software-defined mobility and automated driving from Level 3 upward. This makes it a solution with a great future – whether in wintry Sweden, southern Germany, or anywhere else in the world.
