Air Bag: Description and Operation

Fig.11 Driver Airbag Location:

DRIVER AIRBAG
The driver airbag protective trim cover is the most visible part of the driver airbag system. The driver airbag is mounted directly to the steering wheel. Located under the airbag trim cover are the horn switch, the folded airbag cushion, and the airbag cushion supporting components. The resistive membrane-type horn switch is secured within a plastic tray between the driver airbag cover and the backer plate which is heat staked on to the driver airbag cover.

The driver airbag cannot be repaired, and must be replaced if deployed or in any way damaged. The driver airbag trim cover and the horn switch are available for service replacement.

The driver airbag includes a stamped metal housing to which the cushion and an inflator unit are attached and sealed. The conventional pyrotechnic-type inflator assembly is mounted to studs on the back of the airbag module housing. The inflator seals the hole in the airbag cushion so it can discharge the gas it produces directly into the cushion when supplied with the proper electrical signal. Following an airbag deployment, the airbag cushion quickly deflates by venting this gas towards the instrument panel through the porous fabric material used on the steering wheel side of the airbag cushion.

The protective trim cover is fitted to the front of the airbag and forms a decorative cover in the center of the steering wheel. The inside of the trim cover has locking blocks molded into it that engage a lip on the airbag metal housing. Two stamped metal retainers then fit over the inflator mounting studs on the back of the airbag housing and are engaged in slots on the inside of the cover, securely locking the trim cover into place. The trim cover will split at predetermined breakout lines, then fold back out of the way along with the horn switch and tray unit upon airbag deployment.

Fig.14 Passenger Airbag Location:

PASSENGER AIRBAG
The passenger airbag is located behind the passenger airbag cover, between the glove box and instrument panel top cover.

The passenger airbag includes an aluminum housing within which the cushion and inflator are mounted and sealed. Two stamped metal brackets, one on each end of the housing, enclose the cushion and inflator. The mounting scheme consists of two weld studs and a bracket with two tabs off the bottom of the housing.

Following a passenger airbag deployment, the passenger airbag and the passenger airbag cover must be replaced. If inspection reveals that the passenger airbag mounting points on the instrument panel have been cracked or damaged, the instrument panel assembly must also be replaced. The passenger airbag cannot be repaired, and must be replaced if deployed or in any way damaged.

The hybrid-type inflator assembly includes a small canister of highly compressed argon gas. The inflator seals the hole in the airbag cushion so it can discharge the gas it produces directly into the cushion when supplied with the proper electrical signal. Following an airbag deployment, the airbag cushion quickly deflates by venting this gas through the porous fabric material used on each end panel of the airbag cushion.

The passenger airbag is secured with nuts to the instrument panel beneath the instrument panel top pad and above the glove box opening.

Fig.17 Seat Airbag - Typical:

Seat Airbags, SIACM:

SEAT AIRBAG
The left and right seat airbags are located in the outboard edge of the front seat backs. The airbag contains a bag, an inflator (small canister of highly compressed gas), and a mounting bracket. The seat airbag cannot be repaired and must be replaced if deployed or in any way damaged.

When supplied with the proper electrical signal, the inflator seals the hole in the airbag cushion so it can discharge the compressed gas directly into the cushion. Upon deployment, the seat back trim cover will tear open and allow the seat airbag to fully deploy between the seat and the door.