Electronic brake pressure distribution, operation

The functionality of the electronic brake-force distribution system is integrated within the ETS (N47-2) or ESP control unit (N47-5), allowing the system to operate with no additional sensors. It replaces the automatic load-sensitive proportioning valve (ALB) familiar from the 460/461/463 model series.

The ETS control unit (N47-2) or (N47-5) continuously monitors the rotation rates at all four wheels. When braking occurs, all the wheels slow at the same rate initially. As the braking force increases, however, the rear axle brakes tend to overbrake.

This causes increased slip at the rear wheels. When wheelslip rates rise beyond the defined maxima stored in the ETS (N47-2) or ESP (N47-5) control unit, the system responds to stabilize braking pressure by activating the pressure-maintenance phase in the hydraulic unit. This process entails triggering selected solenoid valves within the hydraulic unit, with no intervention at the high-pressure/return pump (A7/3m1).