# Predictive Brake Assist First Application in Audi A6



## [email protected] (Apr 9, 2004)

The new driver assistance system "Predictive Brake Assist" from Bosch assists drivers in case of imminent accidents by preparing the brake system for an emergency braking. It presents the first stage of the "Predictive Safety Systems", a product line of systems with preventive effect. While unnoticed by the driver, the Predictive Brake Assist builds up a preventive brake pressure by placing the braking pads on the brake disks as a matter of precaution and setting the hydraulic brake assistant into a state of "alert". If the driver actually brakes, he gets the fastest possible brake response with optimal deceleration values and the shortest possible stopping distance. When there is no braking action, the alert status is once again cancelled. The Predictive Brake Assist will be installed for the first time worldwide as additional function of the Adaptive Cruise Control (ACC) in the Audi A6.
The Predictive Safety Systems are part of the Bosch CAPS concept. CAPS (Combined Active and Passive Safety Systems) presents a comprehensive cross linkage of sensors and electronic control units of already in the vehicle existing safety and convenience systems, such as the Electronic Stability Program ESP(r), ACC as well as airbag controls. This leads to novel and extended safety functions.
A look at the accident statistics reveals the great potential of the new Bosch safety systems: about one third of all car accidents are due to collisions with other vehicles or obstacles on the road. Even in critical traffic situations, only some 30 percent of drivers will initiate a full braking action, most drivers are much too hesitant. In cases like this the Predictive Brake Assist helps to prevent accidents or their consequences to a large degree. On the one hand, the system in an identified dangerous situation boosts a too slow deceleration with the hydraulic brake assistant to a full emergency braking maneuver, on the other hand, a full braking effect is reached some 30 milliseconds sooner, since the braking system has been prepared for an emergency braking. Broad estimates say that about 2.5 percent of crashes with oncoming traffic could be avoided in this way, as well as 3.5 percent of accidents in intersections and 5 percent of rear-end collisions.
The Predictive Brake Assist is an upgrading of the ACC from a purely convenience to a safety system. In its basic function, the ACC recognizes vehicles driving in front, measures their speed and keeps the desired safety distance. The heart of the ACC system is a sensor control unit which houses a radar sensor and control unit in a compact entity. The radar sensor detects the vehicle in front up to a distance of 200 meters. The electronic control unit measures the speed and the distances. The ACC then adjusts the speed of one's own vehicle to the flow of traffic through controls of engine and brake system. Once the road is cleared again, the ACC accelerates the vehicle once more to the speed pre-selected by the driver.
In 2006, Bosch plans to launch a Predictive Safety System which gives an early warning to the driver in critical traffic situations – such as by giving a noticeable brake jerk -which will in many cases help to prevent accidents. In a further stage of upgrading, the system will additionally trigger a fully automatic emergency braking with maximum vehicle deceleration if a collision is unavoidable, thus helping to reduce the severity of the accident and its consequences.


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