System functions: Notes
The following system functions of the multiple restraint system (MRS) are described:
- Triggering the multiple restraint system
- Visual and audible seat-belt warning
Triggering the multiple restraint system
Extensive testing has allowed the triggering thresholds to be determined for all possible types of accidents.
The following triggering thresholds were set for activating the different restraint systems:
- Seat-belt tensioner
- Front airbags
- Side airbags and head-level airbags
- Safety battery terminal
- Electric fuel pump
The following examples illustrate how the various restraint systems are triggered:
- Head-on collision
The belt tensioner and the front airbags are activated if frontal impact is sufficient to exceed the triggering thresholds in the MRS control unit.
The belt tensioners have a lower triggering threshold than the front airbags. This means that depending on accident severity, only the belt tensioner may be activated by the MRS control unit.
If the seat-belt buckle switch is faulty, the MRS control unit will attempt to activate the belt tensioner in spite of the error message.
If the seat-occupancy detector is faulty, the control unit assumes that the passenger seat is not occupied. The restraint systems are not activated.
Depending on accident severity, the safety battery terminal is activated and the electric fuel pump switched off.
- Side impact
If the triggering threshold in the MRS control unit is exceeded, the side airbag and the head-level airbag on the side affected by the impact are activated.
Depending on accident severity, the safety battery terminal is activated and the electric fuel pump switched off.
- Front diagonal impact
The airbags and belt tensioners are triggered depending on the rate of vehicle deceleration in a longitudinal or lateral direction.
If several triggering thresholds are exceeded, the corresponding restraint systems will be triggered for frontal collision and/or side impact (front airbag, side airbag, head-level airbag).
Depending on accident severity, the safety battery terminal is activated and the electric fuel pump switched off.
- Rear-end collision
The belt tensioners are activated if rear impact is sufficient to exceed the triggering threshold in the MRS control unit.
Depending on accident severity, the safety battery terminal is activated and the electric fuel pump switched off.
- Rear diagonal impact
The airbags (side airbags, head-level airbags) and belt tensioners are triggered depending on the rate of vehicle deceleration (or acceleration). If a number of triggering thresholds are exceeded, the appropriate restraint systems are activated.
Depending on accident severity, the safety battery terminal is activated and the electric fuel pump switched off.
- Rollover
The MRS control unit does not detect the vehicle rolling over.
The corresponding restraint systems are triggered: for example if the side impact causes the vehicle to roll over or if impact occurs while the vehicle is rolling over and the operating thresholds in the MRS control unit are exceeded.
Depending on accident severity, the safety battery terminal is activated and the electric fuel pump switched off.
- Rear-end collision