Valves of Steering Unit

The proportional valve that adjusts the electronic flow (EVV valve) and the Servotronic valve is activated directly from the ICM control unit. The ICM control unit contains the necessary output stages that are built up using power semiconductors.

Each valve is connected by two lines to the ICM control unit. The ICM control unit calculates the reference values for the aperture of both valves based on the road speed, steering angle and steering-angle speed input signals. These reference values are converted to a pulse-width-modulated signal that is applied at the lines leading to the valves. This means that the ICM control unit can change the aperture of the valves at any time.

Fig 1: Identifying Steering Unit Valves

Courtesy of BMW OF NORTH AMERICA, INC.