Air Bag, Driver: Operation
The multistage Driver AirBag (DAB) and the active vent (domestic market vehicles only) are deployed by electrical signals generated by the Occupant Restraint Controller (ORC) through the DAB squib 1, 2 and 3 circuits to the two initiators in the airbag inflator and the active vent inflator. By using two initiators and an active vent, the airbag can be deployed at multiple levels of force. The force level is managed by the ORC to suit the monitored impact conditions by providing one of several delay intervals between the electrical signals provided to the two initiators and the active vent. The longer the delay between the initiator signals and the later the active vent is released, the less forcefully the DAB will deploy.
When the ORC sends the proper electrical signals to each inflator initiator, the electrical energy generates enough heat to initiate a small pyrotechnic charge which 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 back of the DAB housing 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 DAB trim cover will split at predetermined breakout lines, then fold back out of the way. Following a deployment, the airbag cushion quickly deflates by venting the inert gas towards the instrument panel through discrete vents within the fabric used to construct the back (steering wheel side) panel of the airbag cushion.
The active vent is like a small airbag cushion within the airbag cushion except the active vent cushion slows the deflation of the primary cushion by partially blocking the vents in the primary cushion. The ORC monitors a seat track position sensor on the driver front seat. The ORC signals the active vent Micro Gas Generator (MGG) to deploy in a manner that provides the optimal airbag deployment force to reduce the possibility of an airbag-induced injury.
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 a Supplemental Restraint System (SRS) 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. Refer to HANDLING NON-DEPLOYED SUPPLEMENTAL RESTRAINTS .
The inert gas that is produced when the chemicals are burned during a deployment 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 ORC monitors the condition of the driver airbag through circuit resistance. If any fault is detected the ORC will illuminate the airbag indicator in the instrument cluster and store a Diagnostic Trouble Code (DTC). Proper diagnosis of the DAB inflator and squib circuits requires the use of a diagnostic scan tool and may also require the use of the Airbag Kit. Refer to the appropriate diagnostic information.