BAS PLUS, function - GF30.30-P-3310LE

ENGINES 156, 273, 275 in MODEL 216 up to 31.8.10 with CODE (233) Distronic Plus as of model year 2009/YoM 08

ENGINES 156, 272, 273, 275, 642, 629 in MODEL 221 up to 31.8.10 with CODE (233) Distronic Plus as of model year 2009/YoM 08

Fig 1: View Of Accident-Critical Situation Detection

Courtesy of MERCEDES-BENZ USA

Accident-critical situation detected by the BAS PLUS (Brake Assist System PLUS)

BAS PLUS function requirements, general

"ADTR_AVL" (DISTRONIC PLUS) coded in central gateway control unit (N93)
Radar sensor system not disabled
Long range radar soiling and function test completed
Circuit 61 ON (engine running)
Parking brake not applied
Gear range "D" engaged

BAS PLUS, general

The BAS PLUS function is an additional function of the Brake Assist System (BAS), which assists the driver during emergency braking by means of specific calculations of the brake force for a given situation.

The data from the long and short range radar is used to continuously calculate the potential risk of a collision. If the driver brakes heavy in a critical situation, the brake force is (if necessary) boosted so as to avoid a collision (within physical limits).

Function sequence for BAS PLUS

The function sequence is described in the following steps:

Function sequence for braking torque computation
Function sequence for activation
Function sequence for an accident-critical situation
Function sequence for deactivation

Function sequence for braking torque computation

The sensor data from the long range and short range radars and the input signals are evaluated by the radar sensors control unit (SGR) (N62/1) and the necessary braking torque to support the Brake Assist System is calculated.

The calculated braking torque is transmitted via the chassis CAN (CAN E) to the ESP control unit (N47-5) or regenerative braking system control unit (N30/6) (for hybrid) which controls the brake pressure appropriately via the traction system hydraulic unit (A7/3).

The required braking torque is newly calculated in the process by the radar sensors control unit based on the current clearances and the closing speed and transmitted to the ESP control unit or the regenerative braking system control unit (for hybrid). A partial braking right up to emergency braking of the vehicle can occur depending on the situation.

Function sequence for activation

BAS PLUS is activated when:

A potential accident situation is detected
Heavy driver-induced braking is detected from the brake pedal travel and the actuation speed of the brake pedal
Accelerator not operated
The vehicle is moving forwards

Function sequence for an accident-critical situation

At the current closing speed, the distance of the vehicle from a detected object (vehicle) is detected as critical for an imminent collision. The objects in question are all objects in front of the vehicle that have been detected at least once as moving at speeds (of the host vehicle) up to 70 km/h as well as stationary objects.

Function sequence for deactivation

If the driver applies significant movement to the brake pedal again, at a certain threshold value, brake assistance is withdrawn until braking is by the driver alone (depends on brake pedal travel) and BAS PLUS is deactivated.

The BAS PLUS function is also deactivated if the accelerator pedal is operated.

Component description for regenerative braking system control unit	N30/6 Model 221.095/195	GF42.22-P-1100LEH
Component description for ESP control unit	N47-5 Model 216.3, 221.0/1 except 221.095/195	GF42.45-P-5118LE
Component description for radar sensors control unit	N62/1	GF30.30-P-3301LE