Braking Assistant (BAS) - Operation - GF42.31-P-0001SX

MODEL 221.0 /1, 216.3 up to Model Year 8 

Fig 1: Braking Assistant Reference Graph

Courtesy of MERCEDES-BENZ USA

Investigations with normal drivers in the driving simulator and on the test track have shown that most drivers in emergency braking situations, above all in the initial phase of braking, operate the brake pedal quickly but not hard enough.

A distinction is made between: 

• Hesitant brake application
  • in the initial phase the driver applies too little pedal force and increases it too slowly
• Inadequate brake application
  • the driver applies too little pedal force throughout the entire brake application

To improve these situations, the active safety system Brake Assist (BAS) has been developed. The Brake Assist System is active when the driver brakes very rapidly in an emergency situation. The system detects whether an emergency braking situation exists on the basis of the speed at which the driver presses the brake pedal.

The speed of brake actuation is recorded via the BAS diaphragm travel sensor (A7/7b1) in the BAS brake booster (A7/7). The BAS function is terminated corresponding to the signal of the BAS release switch (A7/7s1) (Pedal not actuated).

The deceleration through BAS is achieved by actuation of the BAS solenoid valve (A7/7y1) in the brake booster.

Benefits: 

• Basic reduction in brake distance in the event of hesitant or inadequate brake application
• Assisting the antilock brake system (ABS) by as large as possible brake force boosting
• ABS maintains the full steerability also in the event of intervention by BAS

The BAS function is triggered by the ESP control unit (N47-5).