Roll Bar: Description and Operation
Roll-Over Protection System
In conjunction with the windscreen frame, the roll-over protection system protects passengers, particularly on the rear seat, if the car should roll over.
The rollover protection system consists of the following components:
Two interchangeable modules each with a triggerable roll-over bar and an actuator
The control module with integrated g sensor and level sensor
Warning light in instrument cluster
1. Roll-over bars
Overview:
Triggering Solenoid:
The two roll-over bars and modules are attached to an subframe behind the rear seat.
If the sensors detect a roll-over situation, the rollover bars are extended through spring force.
The actuators consist, among other things, of solenoids which directly actuate the trigger lever.
2. The control module
Control Module Components:
The control module consists of:
- A g-sensor (g = gravitation), which detects loss of contact with the road surface
- Two level sensors, which detect the vehicle inclination, transverse and longitudinal acceleration
- Evaluation electronics with self-diagnosis
- Capacitors to provide reserve power if the battery voltage fails.
3. Electrical plug connection of the roll-over bar
The plug connections are situated on the rear side of the rollover bar. Before connecting and disconnecting the plug connection, first unscrew the six fastening screws of the rollover bars.
4. Warning light of roll-over protection system
After the ignition has been switched on, the warning light lights up for five seconds.
In the event of a fault, the warning light briefly goes out and then comes back on continuously.
NOTE: The warning light also lights up if the transport lock has been activated via the diagnostic module.
The level sensor
The following parameters can be measured with the aid of the level sensor:
- Vehicle inclination
- Transverse acceleration
- Longitudinal acceleration
The level sensor consists of the following components:
- Spirit level housing which is filled with fluid and contains an air bubble
- Light-emitting diode (LED) (sender function)
- photo transistor (receiver function)
Level Sensor Component View:
If the vehicle exceeds the set limit values during transverse or longitudinal acceleration or pitches around the longitudinal axis by more than the limit value, the air bubble passes through the visual send and receive section. This movement of the air bubble is detected by the receiver and the system is triggered.
Gravitation sensor (g-sensor)
G - Sensor Component View:
The g-sensor is used to detect driving situations in which the vehicle loses contact with the ground (e.g. jumping over a bump).
The g-sensor function is based on a spring/weight system. As a weight, a magnet which counteracts the spring force with the force of its weight is used.
If the vehicle lifts up from the ground the magnet becomes lighter and the spring can press it upward. This closes the reed contact and triggers the system.
Self-test
The roll-over protection system performs its own diagnosis, and carries out a self-test for 5 seconds after the ignition is switched on. The red indicator light in the instrument cluster goes out if no faults are detected during the self-test.
Detected faults are stored and can be read out using the diagnostic module.
Emergency triggering
If the roll-over bars cannot be triggered using the diagnostic module they can be triggered mechanically via a sealed hole in the actuator.
CAUTION: Risk of injury if the roll-over bar is triggered!
- The range of movement of the roll-over protection system must be kept clear during emergency triggering.
Procedure
Manual Unlocking:
1. Insert a screwdriver into the hole in the module and press it against the top edge of the pawl.
2. Press the screwdriver to the left (arrow A) and hold it while pressing down (arrow B). The roll-over bar is triggered.
Retracting the roll-over bars
The rollover bars can be retracted by hand.
Procedure
Manual Retraction:
1. Press the paw to the right.
2. Press the roll-over bar down with your hand.