Passenger Airbag
The horizontal surface of the injection molded, thermoplastic passenger airbag door (1) is the most visible part of the passenger airbag. The passenger airbag door is located above the glove box opening on the top of the instrument panel (2) in front of the front seat passenger seating position.
The outboard edges of the airbag door are secured with integral snap features (3) to the instrument panel base trim. Located below the passenger airbag door (2) within the instrument panel is the passenger airbag unit. The passenger airbag housing fits into a molded receptacle on the back of the airbag door, where twelve stamped hook formations on the forward and rearward edges of the airbag housing are engaged in mating small window openings on the forward and rearward flanges of the receptacle to secure the air-bag door to the airbag housing. These airbag door fasteners and mounting provisions are all concealed beneath the instrument panel base trim. The passenger airbag unit is secured by two screws through a stamped mounting bracket (5) to the instrument panel structural support.
The passenger airbag unit used in this model is a multistage, Next Generation-type that complies with revised federal airbag standards to deploy with less force than those used in some prior models. The passenger airbag unit consists of a stamped and welded metal housing, the airbag cushion, the airbag inflator, and a stamped metal air-bag cushion retainer plate that is secured to the airbag housing with four studs and nuts. The airbag housing contains the airbag inflator and the folded airbag cushion. An approximately 80 centimeter (31.5 inch) wide by 90 centimeter (35.5 inch) high rectangular fabric cushion is used.
The airbag inflator (4) is a non-azide, pyrotechnic-type unit that is secured to and sealed within the airbag housing. A short four-wire pigtail harness with a keyed, yellow connector insulator (1) connects the two inflator initiators to the vehicle electrical system through a dedicated take out and connector of the instrument panel wire harness.
The passenger airbag includes the airbag door. This unit cannot be repaired, and must be replaced if deployed, faulty, or in any way damaged.
The multistage passenger airbag is deployed by electrical signals generated by the Occupant Restraint Controller (ORC) through the passenger airbag squib 1 and squib 2 circuits to the two initiators in the airbag inflator. By using two initiators, the airbag can be deployed at multiple levels of force. The force level is controlled by the ORC to suit the monitored impact conditions by providing one of three delay intervals between the electrical signals provided to the two initiators. The longer the delay between these signals, the less forcefully the airbag will deploy.
When the ORC sends the proper electrical signals to each initiator, the electrical energy generates enough heat to initiate a small pyrotechnic charge which, in turn ignites chemical pellets within the inflator. Once ignited, these chemical pellets burn rapidly and produce a large quantity of inert gas. The inflator is sealed to the airbag cushion and a diffuser in the inflator directs all of the inert gas into the airbag cushion, causing the cushion to inflate. As the cushion inflates, the passenger airbag door will split at predetermined tear seam lines concealed on the inside surface of the door, then the door will pivot up over the top of the instrument panel and out of the way. Following an airbag deployment, the airbag cushion quickly deflates by venting the inert gas through vent holes within the fabric used to construct the back (windshield side) of the airbag cushion.
Typically, both initiators are used during an airbag deployment event. However, it is possible for only one initiator to be used during a deployment due to an airbag system fault; therefore, it is necessary to always confirm that both initiators have been used in order to avoid the improper disposal of potentially live pyrotechnic materials.