Brake Light Switch

ASC MK60 Automatic Stability Control

ASC MK60 is an anti-slip and stability system. The ASC MK60 consists of the following subfunctions: ABS, EBV, CBC and MSR.

Brief description of components
Tandem master brake cylinder
The brake circuits are split diagonally.

Hydraulic unit
The hydraulic unit performs the hydraulic control procedure. The hydraulic unit consists of the following components:

Return pump

Inlet and outlet valves

Damper chambers

Accumulators

Changeover valve

Add-on control module
The add-on control module compares the speed changes of the individual wheels with a reference value; if this is exceeded, the control procedure starts. To secure the functions, the system is subject to permanent self-monitoring. Faults that occur are stored in a fault memory and, if required, displayed to the driver.

Wheel speed sensors
The wheel-speed sensors register the individual wheel speeds and transmit these to the add-on control module.

Main functions
Automatic Stability Control (ASC)
The ASC regulates the wheel that has the tendency to spin in order to preserve driving stability. This takes place by reducing the engine power and braking the spinning wheel. The return pump provides the required brake pressure. Spinning wheels are detected by means of a comparison of the wheel speeds of the front and rear wheels. The system is active when the ignition is switched on and can be deactivated as desired. For driving with snow chains, ASC must be deactivated.

The ASC indicator lamp lights up when

the system is regulating (indicator lamp flickers)

the system has been switched off

a fault has been discovered by the system

Anti-lock braking system - ABS
ABS prevents the wheels from locking when braking and thus retains the steerability of the vehicle. When the add-on control module detects danger of locking, the brake pressure is regulated in the hydraulic unit. First, the inlet valve is closed: the brake pressure can no longer rise. Then the outlet valve is opened to reduce brake pressure. The return pump draws off the return flow of brake fluid and simultaneously ensures there is adequate brake pressure before the inlet valve. Activation of the valves in cycles modulates the brake pressure in such a way that optimum deceleration is achieved.

Engine drag moment control (MSR)
Severe load changes produce a braking force at the drive wheels. The MSR function counteracts this effect by slightly increasing the drive torque.

Cornering Brake Control (CBC)
CBC increases the driving stability in the case of light braking in curves with medium to high lateral acceleration. Here, the pressure at the wheel brakes of the rear axle is modulated individually. CBC begins regulating before ABS becomes active.

Electronic brake force distribution (EBV)
During braking, EBV prevents ABS control from starting in the rear axle before it starts in the front axle. This ensures greater driving stability. If a lockup tendency is detected at the rear wheels, the brake pressure is reduced by activating the inlet valves of the rear wheels. The driver perceives the opening and closing of the outlet valves in cycles in the form of a harder and pulsing pedal feel.