BMW 7 Series: Vertical Dynamics Control
General Information
When driven vigorously or on an uneven road surface, a vehicle tends to respond with undesirable body movements. BMW first developed Vertical Dynamics Control for the E70 and was able to effectively reduce such body motion as a result.
VDC improves the following driver-perception related vehicle characteristics according to road surface conditions:
- Body-related ride comfort (primary ride comfort)
- Roadwheel-related ride comfort (secondary ride comfort)
- Dynamic handling (transitional response, agility) even with more comfortable suspension setting.
BMW is the first manufacturer to offer a damper adjustment system that is continuously controllable independently of damper compression/extension as is the case with the VDC (2) on the F01/F02.
The essential improvements compared with VDC (1) are:
- 1 EDC control valve for damper extension control
- 1 EDC control valve for damper compression control
- "Pre-opening adjustment" for improved body stabilization (has adjustment effect even at low damper rates)
- Driver-perceptible broad spread in conjunction with the handling setting switch (difference between soft and hard characteristics)
- Separately adjustable characteristic for roadwheel-related ride comfort (extension characteristic independent of compression characteristic)
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Fig. 123: Identifying VDC Front Dampers
INDEX REFERENCE CHART
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VDC DAMPER REFERENCE CHART
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Signal Processing
- The vertical movement of the wheels is detected by the wheel-acceleration sensors integrated in the EDC satellite control units
- From the wheel acceleration rates and the ride height signals (FlexRay bus) the vehicle body motion is calculated
- In addition, signals such as the vehicle road speed are read from the FlexRay bus for the purpose of determining required damping forces.
Signal processing/VDC (2) controller
Individual damping forces are calculated for each individual wheel according to the vehicle body motion, the wheel motion and the additional signals read from the FlexRay bus, and are sent every 2.5 ms to the EDC satellite control units.
Damping Force Adjustment
- Stored on each EDC satellite control module is the actual individual damper characteristic, making it possible to minimize differences from the specified characteristic arising from manufacturing tolerances
- From the specified damping force and the damper characteristic data map, the EDC satellite control units calculate the required current to be applied to the damper extension valve and compression valve
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Vertical Dynamics Control (VDC)
Control Unit
Fig. 124: Identifying VDM
INDEX REFERENCE CHART
VDM
The location of the VDM control unit is dependent on the country in which the
vehicle is sold.
On left-hand drive vehicles the c
Electronic Ride-Height Control
Function of Air Springs
The various control modes on the F01/F02 are similar to those on other model
series such as the E70:
Fig. 131: EHC Control Mode Flowchart, F01/F02
Control Modes with Single-a
Electronic Ride-Height Control (EHC)
Control Unit
The EHC control unit is located in a module carrier in the rear of the
luggage compartment on the right-hand
side.
Fig. 132: Identifying Air Supply (LVA) And EHC Control Module On Mount
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If equipped with Equipment
Stop Assistant
Concept
If the driver is no longer fit to drive, the system
helps to safely bring the vehicle to a standstill.
General information
The emergency stop function is not triggered
automatically. The emergency stop function can
only be triggered manually by the occupants.
When the system is activated, t
Seats, mirrors, and steering
wheel
Electrically adjustable seats
Thigh support
Forward/backward, height, seat tilt
Upper backrest
Backrest width
Lumbar support
Backrest tilt, head restraint
Adjusting the head restraint
Height
Push switch up or down.
Adjust distance: manual head restraints
Back: press the button
