BMW 7 Series: System Components

Steering Systems

There are two lateral dynamics systems available on the F01/F02:

• Servotronic
• Integrated Active Steering

Servotronic Components

The proportional valve for electronic volumetric flow control (EVV valve) and the Servotronic valve are directly controlled by the ICM regardless of whether the Servotronic or Integrated Active Steering is fitted.

Fig. 96: Identifying Servotronic Components

SERVOTRONIC COMPONENTS REFERENCE CHART

1. Hydraulic pump
2. Electronic volumetric flow control valve (EVV valve)
3. Servotronic valve
4. Hydraulic power steering control valve body

Fig. 97: Input/Output Signal Diagram - Control Of Steering By ICM

INDEX REFERENCE CHART

1. Steering column switch cluster (SZL)
2. Wheel speed sensor
3. Dynamic stability control (DSC)
4. Electronic volumetric flow control (EVV) valve
5. Servotronic valve
6. Integrated Chassis Management (ICM)
7. "Steering control" function

Components of Integrated Active Steering

Fig. 98: Identifying Integrated Active Steering Components

INDEX REFERENCE CHART

1. Hydraulic fluid reservoir
2. Power steering cooler
3. DME
4. ZGM
5. CAS
6. Instrument cluster
7. DSC
8. AL
9. SZL
10. ICM
11. Hydraulic pump
12. Electronic volumetric flow control (EVV) valve
13. Lock
14. Servotronic valve
15. Actuator unit electric motor
16. Motor angular position sensor

Fig. 99: HSR Actuator Location On Rear Suspension

INDEX REFERENCE CHART

1. Mounting plate
2. Left track rod
3. HSR actuator
4. Right track rod
5. HSR control unit

The special actuator on the rear suspension is fixed underneath a mounting plate on the rear suspension subframe.

The electromechanical actuator is positioned between the two new track rods of the Integral V rear suspension.

The rear-wheel steering system has its own actuator control unit which is responsible for controlling and monitoring the actuator.

It was previously the state of the art that control systems were largely independent of one another.

On the F01/F02, the Integrated Chassis Management (ICM) system brings the separate systems together.

A central ICM control unit in the ICM architecture replaces the previous dynamic handling sensors and forms a central dynamic handling controller.

Fig. 100: Identifying HSR Actuator

INDEX REFERENCE CHART

1. Left track rod joint
2. Left shaft gaiter
3. Worm shaft
4. Worm nut
5. Electric motor
6. Electrical connector
7. Right shaft gaiter
8. Right track rod joint
9. Iron jacket
10. Winding stator
11. Permanent magnet
12. Carrier/armature winding iron core

The electromechanical actuator essentially consists of an electric motor which moves the two track rods by means of a worm-and-nut steering gear.

The actuator is designed for a maximum travel of +-8 mm, which brings about a maximum steering angle of +-3º at the roadwheel.

The worm-and-nut rear-wheel steering gear is self-inhibiting. That means that if the system fails, the vehicle adopts exactly the same handling characteristics as a vehicle without rear-wheel steering.

Fig. 101: Input/Output Signal Diagram - ICM

INDEX REFERENCE CHART

1. Wheel speed sensors
2. DSC
3. SZL with steering-angle sensor
4. Active Steering control unit
5. AS actuating unit
6. HSR control unit
7. HSR actuator unit
8. ICM
9. DSC sensor in ICM (linear acceleration, lateral acceleration and yaw rate sensor)
10. Back-up DSC sensor in ICM (lateral acceleration and yaw rate sensor)

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