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GTR Head restraintsES-6208.09.2006Page 1
HR-7-8GTR Head restraintsDynamic test procedure
Trigger-point in dynamic test procedure
GTR Head restraintsES-6209.06.2005Page 2
HR-7-8GTR Head RestraintsDynamic test procedure – trigger point
– full vehicle sled test (without wheels, fluids)
– synthetic sinusoidal pulse peak acceleration: 86 m/s² (corridor defined)max velocity (delta v): 17, 3 km/h ± 0,6 km/h
– 50th-percentile male Hybrid III test dummy (49 CFR § 572, Subpart E)
– angular rotation between head and torso 12°
– HIC15 500
FMVSS 202a provides a dynamic test procedure as compliance option for front outboard designated seating positions
GTR Head restraintsES-6209.06.2005Page 3
HR-7-8GTR Head RestraintsDynamic test procedure – trigger point
GTR Head restraintsES-6209.06.2005Page 4
HR-7-8GTR Head RestraintsDynamic test procedure – trigger point
Active head restraint system
– reducing of backset in case of rear end collision by moving head restraints front surface;
– energy store (e.g. preloaded spring, pyrotechnic actuator);
– Activation by control unit (e.g. airbag-control-unit)
– Activation dependant on algorithm which is implemented in control unit and is based on various sensor signals received in real world crash;
GTR Head restraintsES-6209.06.2005Page 5
HR-7-8GTR Head RestraintsDynamic test procedure – trigger point
Comparison of vehicle accelerations in test procedures concerning rear end collisions
– FMVSS 202a dynamic test;
– barrier test (with equivalent velocity change)
GTR Head restraintsES-6209.06.2005Page 6
HR-7-8GTR Head RestraintsDynamic test procedure – trigger point
Barrier test for rear end collision
Dynamic test with movable barrier to test for vehicle in rear end collisions. The barrier test shall cause a corresponding velocity change (energy) to the FMVSS 202a dynamic test; The impact speed of the barrier is vehicle specific– movable barrier
(longitudinal direction) impacts vehicle at standstill from rear;
– barrier weight 1400 kg;
– 10° angle of barrier to vehicle longitudinal axis;
– 40% offset;
– approx. 35 km/h barrier impact speed
(dependant on mass of struck vehicle);
GTR Head restraintsES-6209.06.2005Page 7
HR-7-8GTR Head RestraintsDynamic test procedure – trigger point
Comparison of sensed vehicle accelerationsA
ccele
rati
on [
m
/s²
]
Time [ s ]
barrier test
FMVSS 202a
Acceleration sensor signal at vehicle body (B-pillar position)
GTR Head restraintsES-6209.06.2005Page 8
HR-7-8GTR Head RestraintsDynamic test procedure – trigger point
Deployment of active head restraint
The software and data in the control units contain:
– plausibility checks of sensor signals;
– discrimination routines for crash severity;
The deployment algorithm of an active head restraint is contained in the control unit.(e.g. airbag control unit)
The deployment algorithm evaluates various sensor signals (e.g. linear acceleration; rotational acceleration, deformation)
GTR Head restraintsES-6209.06.2005Page 9
HR-7-8GTR Head RestraintsDynamic test procedure – trigger point
The active head restraint may not deploy if vehicle is subjected to a dynamic test according to FMVSS 202a.
The active head restraint will deploy if vehicle is subjected to a rear end collision with a velocity change of the vehicle of 17, 3 km/h.
GTR Head restraintsES-6209.06.2005Page 10
HR-7-8GTR Head RestraintsDynamic test procedure – trigger point
Proposal for active head restraints in dynamic test procedure
– Dynamic test procedure according to FMVSS 202a with battery installed and ignition “ON”;
(Airbag system operable)
– Usage of trigger point for active head restraints in dynamic test procedure according to FMVSS 202a
on request of the vehicle manufacturer;
– Vehicle specific trigger point according to manufacturer’s information;
– Manufacturer must provide data of a standardized barrier test (rear end collision) with energy level (delta v 17,3 km/h) of FMVSS 202a pulse;