BMW 7 Series: Display And Control Elements

Fig. 94: Display Function Illumination And Active Blind Spot Detection Button

DRIVER ASSISTANCE SYSTEM REFERENCE CHART

1. Function illumination
2. Active Blind Spot Detection button

LIN-bus Connections

Fig. 95: LIN Bus Connections At Footwell Module

LIN BUS CONNECTIONS REFERENCE CHART

ASP_FA - Driver's door mirror
ASP_BF - Front passenger door mirror
BE_FAS - Operating unit for driver assistance systems
FRM - Footwell module

The operating unit for the driver assistance systems is fitted with a button that can switch the Active Blind Spot Detection system on and off.

The operating unit is connected via the LIN bus to the footwell module (FRM). A bus signal from the FRM to the ICM is used to inform that the button has been pressed.

The ICM only permits the Active Blind Spot Detection to be switched on, if the system is working faultlessly.

Only then does it send a positive response via a bus signal to the FRM, to activate the function illumination on the button.

If instead there is a fault with the system, the function illumination remains off despite being pressed. The driver will then know that the system is not available.

Warning Light in the Driver's Door Mirror

There is a triangular-shaped warning light in the left and right door mirror. This lights up two-dimensionally and can be activated in different intensities.

The ICM sends a request together with the requested intensity to the footwell module.

Using the LIN bus, the request is passed on to the electrical system of the respective door mirrors. Amplitude-modulated control is used to light up the LEDs in the door mirror.

Vibration Actuator in the Steering Wheel

The vibration actuator is housed in the six o'clock spoke of the steering wheel. It has the task of causing the steering wheel to vibrate.

The Lane Departure Warning and Active Blind Spot Detection systems use this vibration, in order to alert the driver of dangerous situations. In both systems, the warning is executed by vibrating the steering wheel.

The steering wheel module that controls the vibration actuator is also housed in the interior of the steering wheel. This produces an alternating voltage that causes the vibration actuator to oscillate. The frequency of the alternating voltage is not changed during operation. It is designed so that oscillations from the vibration actuator fit perfectly to the overall steering wheel system.

The amplitude of the alternating voltage can be changed using the steering wheel module. Therefore, you have the option of different systems with varying oscillating amplitudes available to you for the warning.

Fig. 96: Identifying Steering Wheel With Vibration Actuator

STEERING WHEEL LEGENDS

1. Steering wheel module (LRE)
2. Vibration actuator

The E6x LCI is already equipped with the driver assistance system called lane departure warning which has already used steering wheel vibration to warn the driver in a similar way. Here a vibration motor is used as the vibration actuator. An unbalance mass is located on the shaft. If the vibration motor is activated, the unbalance mass rotates and thus produces the vibrations.

The vibration actuator in the F01/F02 has undergone a significant advancement in comparison with the vibration motor. Instead of the unbalance motor, a structural element is used that only oscillates in a longitudinal direction. For this reason, it is known as a "longitudinal oscillator". This active principle has the advantage that the vibrations are only induced in this one direction. The vibration actuator is built into the steering wheel so that the direction of its oscillations corresponds with the direction of rotation of the steering wheel. This provides an ideal expression of the warning and the driver is made immediately aware that he must use the steering wheel to avert the dangerous situation. In addition, this principle to a large extent avoids unwanted side-effects such as noises or oscillations that could be transferred in other directions to the body.

The two brackets connect the vibration actuator with the steering wheel. However, the brackets on the vibration actuator are not screwed to the case, but to the coil carrier.

Fig. 97: Exploded View Of Vibration Actuator

VIBRATION ACTUATOR LEGENDS

1. Left bracket
2. Left case section
3. Permanent magnet
4. Spring
5. Coil carrier
6. Coil
7. Electrical connection
8. Spring
9. Right case section
10. Right bracket

This means the coil carrier is fixed in place. The permanent magnet can move instead. It is set into an oscillating motion in the direction shown, when alternating voltage is applied to the coil. The longitudinal movement of the permanent magnet is transferred to both case sections due to its length. This is why the case sections also have a long slot in the electrical connection area to the coil. The springs ensure that the case sections do not hit against their end positions and therefore prevent noises.

The request to activate the vibration actuator is sent from the Integrated Chassis Management over the FlexRay to the steering column switch cluster (SZL). The SZL guides this request via LIN bus further to the steering wheel module (LRE).

Fig. 98: LIN Bus Subscribers Of Steering Column Switch Cluster

LIN BUS REFERENCE CHART

LRE - Steering wheel module
SZL - Steering column switch cluster

Instrument Cluster

There are no function displays for the Active Blind Spot Detection system in the instrument cluster (different to the lane departure warning). Instead Check Control messages are displayed in the instrument cluster, when the Active Blind Spot Detection system is not available. A distinction is made between two possible causes:

ACTIVE BLIND SPOT DETECTION SYSTEM CAUSES REFERENCE CHART

Active Blind Spot Detection deactivated (due to functional peripheral factors such as, blindness)

Active Blind Spot Detection failure (due to real faults or defects with components)

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