Components - Operation

RPS COMPONENTS - OPERATION

The main components of the RPS includes the following:

TWO ROLL BAR CASSETTES




The cassettes are positioned in a reinforced body structure, behind the rear seat backrests. Each cassette assembly consists of a "U" shaped bar that is guided by low friction plastic bushings. The bar is held in the retracted positioned against spring pressure by a lever. The lever is solenoid controlled to unlock the bar for deployment. The two springs ensure that the bar will deploy quickly to provide adequate protection.

When deployed, the bar is held in place by a ratchet and lever assembly that locks the bar in the raised position.







Technical Data
Cassette dimensions 249 x 507 x 75mm (retracted)
Maximum bar travel 270 mm
Construction Light alloy steel
Cassette weight 5 kgs (11 lbs)
Absorption force 35 KN

RPS COMPONENTS/OPERATION

Roll Bar Retracted




Roll Bar Deployed




ROLLOVER SENSOR




The rollover sensor in mounted on the longitudinal axis of the vehicle, behind the left backrest. It contains the sensors and control electronics for roll bar deployment.

CONTROL ELECTRONICS
The control electronics include the monitoring circuits for roll bar operation and two capacitors for triggering the roll bars in the event of an electrical failure.

CLINOMETER - (TILT DETECTION)
The clinometer identifies the vehicle's inclination and determines transverse and longitudinal acceleration.




The clinometer consists of three air bubble floats with LED transmitters and photo transistor/receivers. Two of the floats are positioned on opposing angles of 52° to the horizontal axis of the vehicle.

As the vehicle starts to rollover sideways the air bubble will move across the transmitter/receiver circuit when the angel passes 52°. This will signal the electronics to deploy the roll bars. The critical angle for rollover on the E36 convertible is 62°.




The third air bubble float is positioned at an angle of 72° to the longitudinal axis of the vehicle. If the vehicle starts to rollover end to end, the sensor will cause deployment of the rollover bars.




If the vehicle slips sideways into an obstacle (i.e.: the curb) the transverse acceleration is retarded rapidly.




The effect of the vehicle hitting the curb will force the air bubble in the float downwards, before the vehicle starts to rollover. In doing so the air bubble can pass the transmitter/receiver circuit and trigger the deployment of the bars.

This requires an acceleration force of at least 1.28 "G" lasting for approximately 80ms.

"G" SENSOR - detects vehicle's loss of contact with the road surface
If the vehicle becomes airborne, and the rate of acceleration is 1 "G"or more, the effective weight of the vehicle is zero. At this point, the clinometers can no longet detect transverse acceleration with respect to the gravitational pull. In this situation, the "G" sensor will act as the triggering device for the roll bars.




The "G"sensor consists of a reed contact, magnet and spring assembly..As long as the vehicle is in contact with the road surface, the spring does not have enough tension to overcome the weight of the magnet and gravity.




However, if the vehicle becomes airborne, and weightlessness occurs, the spring will force the magnet up which opens the reed contact and triggers the deployment of the roll bars.

A time period of approximately .3 seconds with a "G" force of approximately 0.9 or less is required before the roll bars will deploy.

RPS DIAGNOSIS AND TESTING







The roll over sensor performs a self check every time the ignition key is switched on. All components of the sensor are checked including the output stages for the roll over bar solenoids. If a fault is detected, the warning lamp in the cluster is illuminated and the fault is logged in the memory of the convertible top control module.

In the event of a power failure, the capacitors in the sensor can still trigger the solenoids for approximately 5 seconds.

The operation of the roll over protection system must be checked as every inspection I & II. The operation of the system is checked using the DIS tester or MoDiC to trigger the deployment of the roll bars. A signal is sent from the Convertible top module to the roll over sensor to activate the system.

The total number of times the system is activated is stored in the memory of the top module. It can be read out though the tester display.

After fifty activations of the system, it must be inspected for wear. Refer to the repair manual for the proper checking procedures.