The beginnings of Bosch’s antilock braking system

In 1936, Bosch registered a patent for a “mechanism to prevent locking of the wheels of a motor vehicle.” At one time or another, almost every driver discovered that wheels lock under heavy braking, making the vehicle impossible to steer. The physical reality – that a wheel still rolling during braking requires a significantly shorter braking distance than a wheel that has locked, and helps keep a vehicle stable and steerable – was also already well known. Despite considerable efforts, a breakthrough was not yet on the horizon: the antilock systems fell victim to the sluggishness of their mechanical controls and were unable to react quickly enough to the ultra-rapid change in conditions during braking.
The availability of semiconductor technology starting in the early 1960s set the stage for what was to come. Electronics made it possible to reduce or increase braking pressure at an appropriately rapid speed. In 1969, Bosch began in-house predevelopment on an antilock braking system.

Velocity sensors of an antilock system for passenger vehicles, 1969

Velocity sensors of an antilock system for passenger vehicles, 1969

ABS 2 components (hydraulic modulator and control unit), 1978

ABS 2 components (hydraulic modulator and control unit), 1978

At the time, Heidelberg-based Teldix GmbH had already been performing research on an antilock system for vehicles for five years and had developed a promising electronically controlled antilock braking system that could control all four wheels independently of each other. The system was met with great interest by the automotive industry, and preparations for mass production got underway. However, it turned out that the analog electronics available back then did not satisfy the safety requirements for a braking system. Extensive winter testing proved the ability of the ABS 1 system to function, but the electronics were not sufficiently durable. After acquiring a 50 percent stake in Teldix in 1973, the main contribution made by Bosch was its development and manufacturing experience with electronic components, which were robust enough for use in vehicles. In 1975, Bosch took over full responsibility for ABS development and later bought up all the remaining Teldix shares. In 1978, Bosch and Mercedes-Benz presented the ABS 2.

ABS 2 testing phase, 1976: measuring the braking distance on an icy road with a Peiseler wheel

ABS 2 testing phase, 1976: measuring the braking distance on an icy road with a Peiseler wheel

The antilock braking system reliably stopped wheels from locking up under heavy braking and kept vehicles steerable, helping avoid uncontrolled skidding following emergency braking in many cases. From the start, the additional safety was undisputed. ABS 2 and its successors gradually became standard equipment in all vehicle segments. Today, they have been helping guarantee safe braking for four decades.

How ABS works during emergency braking on a slick road: left without ABS (car skids in the bend), right with ABS

How ABS works during emergency braking on a slick road: left without ABS (car skids in the bend), right with ABS

 

The development of the anti-lock braking system marks the beginning of digital assistance systems in the vehicle. Brake control systems such as ABS and ESP® pave the way for the mobility of the future and are indispensable for the vision of automated driving, for example in the form of the predictive emergency braking system. More information can be found here: https://www.bosch-mobility-solutions.com/en/products-and-services/passenger-cars-and-light-commercial-vehicles/driver-assistance-systems/predictive-emergency-braking-system/

 

 

 

 

One Response

  1. Mechanical design

    As a background from Mechanical engineer this blog was very useful with information stuff. Keep writing such articles. Looking forward for more post.Thanks

    Reply

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