Operation

OPERATION

WARNING:
Some of the chemicals used to create the inert gas may be considered hazardous while in their solid state before they are burned, but they are securely sealed within the airbag inflator. Typically, both initiators are used and all potentially hazardous chemicals are burned 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 or hazardous materials.

The inert gas that is produced when the chemicals are burned is harmless. However, a small amount of residue from the burned chemicals may cause some temporary discomfort if it contacts the skin, eyes, or breathing passages. If skin or eye irritation is noted, rinse the affected area with plenty of cool, clean water. If breathing passages are irritated, move to another area where there is plenty of clean, fresh air to breath. If the irritation is not alleviated by these actions, contact a physician.


The airbag 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. A radial deploying fabric airbag cushion with internal tethers is used. The airbag inflator is a dual-initiator, non-azide, pyrotechnic-type unit with four mounting studs and is secured to the stamped metal airbag housing using four hex nuts with washers. The driver airbag cannot be repaired, and must be replaced if deployed or in any way damaged.

The multistage driver airbag is deployed by electrical signals generated by the Occupant Restraint Controller (ORC) through the driver 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 four 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.

AIRBAG DEPLOYMENT SEQUENCE





1. When the actuation impact threshold for the driver side airbag is exceeded, an electric pulse is transmitted to the squib in the gas generator by the Seat Belt Tensioner (SBT) and Occupant Restraint Controller (ORC).
2. The squib ignites the solid fuel in the gas generator. The solid fuel combusts, developing a gas which explodes under high pressure into the airbag through a filter.




3. The airbag inflates and tears open the steering wheel cushion cover at a predetermined breaking point.




4. While continuously inflating, the airbag begins to exit the steering wheel cushion.




5. After approximately 45 ms. the airbag reaches its maximum volume.
6. When the maximum volume is reached, the pressure in the airbag starts decreasing immediately. The gas escapes from the airbag through a filter and the airbag deflates.