Browse Publications Technical Papers 2005-01-1219

Lightweight Easy Opening Invisible Airbag Lid R.A.L.F. - Reinforced Airbag Lid in Foam 2005-01-1219

The role of a cockpit within the safety restraint system is to provide a technically reliable airbag-lid function for passenger and knee airbag modules. The concept must also be in line with aesthetic and styling requirements from the OEM. The goal for current and future systems is to have invisible airbag-lids integrated into the overall cockpit design.
With the new FMVSS 208 requirements, the restraint system performance requires more tuning and the role of each component must be developed in an integrated way. Especially, the Out of Position (OoP) performance can be affected by the position and the design of a passenger airbag (PAB) lid.
The content of this paper describes the new airbag-lid concept “RALF” (Reinforced Airbag Lid in Foam) that can be considered as one step towards the integration of an airbag module into the cockpit. Main focus of this integration is the compliance to the new FMVSS 208 requirements.
The chosen principle for this solution is that, the accelerated mass in case of an airbag deployment is minimized, therefore the kinetic energy content and the force to accelerate the airbag-lid is minimized. In the “RALF” concept the typical weight of a complete airbag-lid ranges from 70 g - 100 g. while most optimized airbag lids with sheet metal insert weigh between 250 g and 400g. The “RALF” concept contains a “soft” / flexible airbag-lid.
Most of the invisible airbag lids are made from a stiff material (hard plastic or sheet metal). The position of such a hard airbag lid in the Instrument panel is determined by two factors:
  1. 1
    It should be out of range for the OoP scenarios so it won't interact with the test dummy's head
  2. 2
    In case of airbag deployment, contact of the airbag lid to the windscreen is critical because the windscreen could be damaged when hit from a hard lid.
A soft airbag lid design offers an additional degree of freedom for designing the Cockpit, because interaction of the airbag lid with the test dummy and/or the windscreen can be permitted.
Additionally to the safety aspect, a Passenger airbag that is located very close to the windscreen offers high value of free package volume close to the passenger. This additional space could be used for storage bins or a bigger glove box.


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