Bosch upgardes its antilock braking system
ABS 8.1: smaller, quieter and more efficient 

Motion Trends,
30th January 2006.

Already known for over a quarter of a century, the antilock braking system, or ABS, has been through many enhancements.

Now is the time for a new leap forward.

Smaller and quieter, the upgraded Bosch ABS goes into production with greatly reduced noise emission, less installation space required due to more efficient hydraulics and, most importantly,
optimized braking power on slippery surface.

The hydraulics component of the new Bosch ABS 8.1 which has started production, is some 20 percent smaller and lighter than the previous version.

Moreover, the developers succeeded in reducing braking distances even further especially on slippery surfaces.

It is quieter during control actions and the brake pedal produces less vibrations. "This new version meets the objectives of OEMs for a greater reduction of weight and installation space of every single unit", explains Klaus Meder, Vice President Development of the Bosch Division Chassis Systems Control.

The improvements stem from a more efficient control loop for the motor of the return pump, the speed of which can now be adjusted to the driving situation. This allowed engineers to use a smaller sized electric motor, the decisive factor for achieving a downsizing of the unit.

In addition, pump and valve triggering have been optimized in the course of the product development.

In its most compact version, the box volume of the hydraulic unit plus add-on ECU now stays below the 1-liter mark and has a weight of merely 1.4 kilograms.

The variable speed control of the electric motor causes a further reduction of vibrations and the noise produced in the process.

Bosch engineers also succeeded in noticeably suppressing the intensity of the higher-frequency emitting signals in the operating noise. This is generally perceived as more pleasant and greatly contributes to the comfort of the vehicle passengers.

On roads with a low coefficient of friction, that is on wet, snow-covered or icy surfaces, ABS 8.1 will reduce the stopping distance even further and the lower power consumption of the compact pump motor will not drain the vehicle electrical system.

Antilock braking systems prevent the locking of wheels when executing an emergency braking. The vehicle can still be steered – which allows the driver to slam on the brakes and simultaneously avoid obstacles.

Bosch was the first supplier worldwide to offer an electronically controlled, mass-produced antilock braking system. It was for the first time installed in 1978 in the Mercedes-Benz S-Class and a short while later in the BMW 7series. Ever since, Bosch delivered some 130 million brake control systems with ABS function to OEMs all over the world.