Servotronic (SVT) - Active Steering / Integrated Chassis Management: Notes

Servotronic is a transverse dynamics system. Servotronic has the task of continuously adapting the steering servo depending on the driving speed and steering angle. For this purpose, Servotronic correspondingly controls the electrical current of the Servotronic valve so that the flow of hydraulic fluid assists steering to a greater or lesser extent. The current steering angle is additionally taken into account in order to harmonize the steering assistance based on the steering angle. The steering servo is determined with the aid of characteristic maps and decreases with increasing driving speed, thus increasing the amount of steering torque required.

Steering servo is realized by means of a conventional rack and pinion power steering gear. The size and direction of the hydraulic forces acting on the rack depend on the rotational angle of the torsion bar spring. torsion bar spring is located between the steering shaft and pinion.

The control unit responsible for the Servotronic function contains the following components:

Servotronic output stage
Servotronic software

The Servotronic function can be realized by different control units:

E70 without active steering built after 04/2010 = Servotronic control unit (SVT)
E70 with active steering = active steering (AL)
E71, E71M and E70M = Integrated Chassis Management (ICM)

Servotronic is optionally available for the E70 without active steering (AL) as from 04/21010. Vehicles without active steering do not have active steering (AL). The Servotronic control unit (SVT) is additionally installed in these vehicles.

NOTE: Vehicles without active steering!

This functional description describes the Servotronic function on the E70 built after 04/2010 without active steering.