Emergency brake assist
A brake assist system (BAS ) is a brake booster in an automobile, which ensures that the necessary pressure on the pedal to trigger an emergency braking is increased in an apparent (emergency) braking maneuvers up to the maximum possible braking pressure. The basis for this change of the brake gain characteristics, among other things, the time between the last pulse of gas, and the operation of the brake pedal ( emergency braking ) and the speed at which the accelerator pedal is released. Through an active turn of the brake assist in this way by the driver, it differs from the emergency braking system which performs initiated by the onboard computer of the vehicle braking. A wheel lock is thereby prevented by the anti -lock braking system (ABS).
Basics
The BAS is an important link in a chain of assistance systems, the development of the ABS began. Based on the ABS initially created the Traction Control System ( TCS, 1985). This was followed by the automatic locking differential ( ASD, 1985) and the automatically switching four-wheel drive 4MATIC (1985). Also, the Electronic Stability Program ESP (1995 ) used ABS signals. The brake assist system builds directly on the ESP functions. From it eventually became the Brake Assist PLUS (BAS PLUS). He warns the driver visually and audibly before an impending rear-end collision and automatically calculates the required braking pressure to prevent the crash. The interplay of all components provided a rating based on forward-looking sensors, adaptive feedforward control of the braking system a further innovation for optimal delay of the car in dangerous situations dar.
These systems are classified differently according to vehicle manufacturers and automotive suppliers:
- BMW: intelligent brake ( iBrake )
- Daimler AG: Pre-Safe brake
- Ford Motor Company: Active City Stop
- Robert Bosch GmbH: Predictive Safety System (PSS )
- Volvo: City Safety
Function and operation
Technically, a partially evacuated chamber with atmospheric air pressure is applied in the brake booster, so that changes the brake booster. Alternatively, it is the same with a hydraulic or mechanical. It is triggered via an electronic control.
Older methods measure using a sensor the traversed path of the brake pedal with respect to the elapsed time and then calculate the instantaneous velocity and possibly even accelerating the brake pedal came. The sensor operates according to potentiometric principles, ie The mechanical Pedalwegwert is assigned to an equivalent electrical value, which is evaluated in the downstream ABS / ESP system.
Newer systems work similarly as above, except that the sensor is not on the brake pedal, but integrated is installed in the master brake cylinder.
Characteristic of false initiated emergency braking are especially braking maneuvers that begin with high brake pedal speed, but then even before reaching the required braking pressure to subside intensity (negative brake pedal acceleration). BAS in the integrated ABS / ESP system detects this and then establishes the necessary high braking for the emergency braking pressure in the master cylinder. Because the most important during an ABS braking time of the commencement of braking with the highest possible braking pressure, the BAS can shorten the braking distance something here at too gently braking the driver.
Light of the introduction is the behavior of many motorists, not optimal to respond in an emergency braking situation and initiate no full braking of the vehicle.
Potential
With the standard installation of collision warning and emergency braking systems in cars could avoid many serious rear-end collisions after calculations of accident researchers, as too cautious and late braking occurs frequently in dangerous situations. Then with modern brake assist would be possible to reduce the serious car accidents by 12%.
The Insurers Accident Research ( UDV ) speaks according to his own calculations for the use of Brake Assist. In addition to the mandatory on all new cars in Europe from 2011 ESP anti-skid would promise collision warning and emergency braking systems, the highest accident avoidance potential.
Legal position
In the EU, the rule that since November 24, 2009 already had to be fitted as standard with Brake Assist, all new passenger car and light commercial vehicle types applies. Since 24 February 2011, this applies to all newly registered vehicles.