ESP(R) braking torque closed-loop control circuit, function

Normal mode

This is the case when the driving state requires no control mode.

Anti-lock braking system (ABS)

The wheel speed signals are used by the Electronic Stability Program (ESP) control unit (N30/4) to determine whether the criteria for ABS control exist. The corresponding regulating valves of the traction system hydraulic unit are then actuated individually.

Acceleration slip regulation (ASR)

As soon as a drive wheel has a tendency to spin, the ESP® control unit actuates the corresponding regulating valves of the traction system hydraulic unit.

Engine drag torque control (MSR)

As an addition to ASR, EBR optimizes slip at the drive wheels when the accelerator is released. Excessive wheel slip is prevented by means of a precisely controlled increase in power. The EBR also prevents the drive wheels from slipping on slippery road surfaces.

Electronic brake force distribution (EBD)

EBD uses the difference in speed between the wheels on the front and rear axles to determine the maximum permissible brake pressure for the rear wheel brakes. Based on the vehicle load, EBV regulates the brake pressure at the rear axle so that overbraking is prevented. EBD replaces the original pressure-dependent and load-dependent brake force regulator.

Brake Assist System (BAS)

From the actuation speed of the brake pedal, the ESP® control unit detects that an emergency stop situation exists, and initiates BAS mode.

Electronic Stability Program (ESP®)

The signals for the wheel speeds, steering angle, turn rate and lateral/longitudinal acceleration of the vehicle as well as the brake pressure are captured and processed in the ESP® control unit. After the input signals are evaluated, the corresponding regulating valves of the traction system hydraulic unit are actuated in order to control the brake pressure.

Control mode with deactivated ESP®

When the ESP® OFF button (S76/6) is pressed, the ASR is switched off; ESP®, however, remains active. At a speed > 50 km/h or if the vehicle gets into an unstable driving situation, the ASR is switched on again automatically.