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Background, Description and Evaluation of a New Side Airbag System
Technical Paper
1994-20-0119
Sector:
Language:
English
Abstract
Side impacts give rise to relatively more severe injuries than
frontal impacts. A Swedish study has shown that the neck and the
legs of the struck side occupant need to be better protected due to
a risk of permanent disabilities. The head, chest and
abdomen/pelvis need to better protected from a risk of life
threatening injuries.
Improved protection in side impacts can be achieved with car
body/door reinforcements and compliant bolstering (padding and/or
airbag) on the inside of the door. A study has shown that a
ventilated airbag of about 12 liter in volume, covering both the
chest and the abdomen down to the armrest level, improves the
protection in side impacts better than 50 mm of compliant chest
padding. A suitable initial bag (over) pressure was found to be
about 40 kPa. The 12 liter ventilated airbag resulted in 30-40%
lower chest deflection and about 60% lower VC than the 50 mm
padding in sled tests simulating full-scale tests. The airbag
during its compression must be softer than the corresponding human
body segment. The TTI was 30-45% lower with the bag. The deflection
based criteria were found to be very sensitive to the door
velocity. Pelvis padding (75 mm thick) effectively reduced the
pelvic loads. The head ejection through the side window frame was
reduced by an average of 30 mm by the side airbag and the neck load
was also reduced.
The paper describes a door mounted side airbag system (including
sensor) as well as a seat mounted system. The latter system has
been developed by Autoliv together with Volvo and is the first side
airbag system installed in serial produced cars for the 1995 model
year.
To further improve the protection of the head/neck in side
impacts a supplementary protective device, the "curtain",
at the side window has been proposed.