Brake Intervention (ADB)

Brake intervention is applied to the individual drive wheel which is loosing traction by regulating the brake calipers in three phases:

• Pressure Build
• Pressure Hold
• Pressure Release

When brake intervention is necessary, the front wheels must be isolated from the Pressure Build sequence in the hydraulic unit.

Here is an example of an ASC brake intervention at the left rear wheel:

• The Changeover Valve for the rear brake circuit, the right rear and both front Inlet Valves are energized and closed.
• The rear brake circuit Intake Valve is energized and opened.
• The Return/Pressure pump is activated and draws brake fluid through the open Intake Valve from the Master Cylinder (via the Central Valve)  and delivers the pressurized fluid to the open Inlet Valve braking the left rear wheel.
• Pressure Hold and Pressure Release are done by cycling the Inlet and Outlet Valves similar to the ABS sequence described previously.

The control unit decides which regulation method should take place based on input criteria and chooses from two regulating principles:

• Select-High
• Select-Low