5 Series E60 525xd (M57T2) SAL
The direction and severity of an impact is detected by the acceleration sensors in the crash safety module and
by external acceleration sensors.
External acceleration sensors:
•
Front airbag sensor, driver's side and front airbag sensor, passenger's side
•
Airbag sensor on driver's door and airbag sensor on front passenger's door
•
Airbag sensor on driver's side B-pillar and passenger's side B-pillar
The crash safety module processes all acceleration data. This is used to determine the accident severity.
Triggering of safety 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 tensioners
•
End fitting pretensioner
•
Front airbags
•
Knee airbags
•
Side airbags
•
Head airbags
•
Active head restraint
•
Adaptive belt force limiter
The restraint systems are triggered only when 2 independent sensors detect the corresponding threshold.
For example, a frontal collision is detected by the longitudinal acceleration sensor in the airbag sensor in the
driver's side B-pillar and by the longitudinal acceleration sensor in the crash safety module. The crash safety
module calculates the direction of the impact and the collision severity from the data sent by the sensors.
Depending on accident severity, the safety battery terminal is activated and the electric fuel pump switched off.
Triggering of the various restraint systems is illustrated based on two examples (frontal impact and side impact):
•
Head-on collision
The restraint systems (seat belt tensioner, end fitting pretensioner, front airbag, knee airbag, adaptive belt
force limiter) are triggered when the force of the frontal impact is so strong that the triggering thresholds in
the crash sensor module are exceeded.
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 crash safety module.
If the seat belt buckle switch is faulty, the crash safety module 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 occupied. The
restraint systems are 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 crash safety module 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.
Data storage in the case of safety system triggering
SBT Crash safety (ACSM) E60, E61, E63, E64, E70, E85, E93
BMW AG - TIS
21.02.2013 11:34
Issue status (12/2007) Valid only until next DVD is issued
Copyright
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