Driver's/front passenger's side airbag, function - GF91.60-P-4004-02Q

A side impact is reported to the restraint systems control unit (N2/7) via the left side airbag and window airbag sensor (A53/1) or the right side airbag and window airbag sensor (A54/1). The restraint systems control unit (N2/7) checks these values for their plausibility and as a consequence triggers an ignition pulse for the corresponding side airbag.

Operating procedure 

If the triggering threshold for the side airbag is exceeded, an electrical ignition pulse is delivered from the restraint systems control unit (N2/7) to the left front side airbag ignition squib (R12/20) or right front side airbag ignition squib (R12/21). The squib ignites the solid fuel rings in the fuel chamber. The solid fuel burns. The burst disk is welded on during this combustion process.

The compressed inert gas mixture (argon/helium) now escapes from the composite pressure vessel, mixes with the gases of combustion and is led into the airbag via the exhaust vents. In doing so the escaping gas is heated by the burned off solid fuel, whereupon this additionally increases the volume of gas. Under the pressure of the in flowing gas, the inflating airbag tears open the side airbag housing and the predetermined fracture point in the door lining and enters the interior.

The airbag reaches its full volume within approximately 20 msec.

Once maximum volume is reached, pressure is decreased in the airbag immediately. The gas escapes from the airbag via a filter and the airbag folds up.