Knee Blocker Air Bag - Operation

OPERATION

The knee blocker airbag (also known as the Knee AirBag/KAB or the Inflatable Knee Blocker/IKB) is deployed by an electrical signal generated by the Occupant Restraint Controller (ORC) to which it is connected through a knee blocker line 1 and line 2 (or squib) circuits to the initiator in the airbag inflator. The hybrid-type inflator assembly for the airbag contains a small canister of highly compressed inert gas. When the ORC sends the proper electrical signal to the airbag inflator, the electrical energy creates enough heat to ignite chemical pellets within the inflator.

Once ignited, these chemical pellets burn rapidly and produce the pressure necessary to rupture a containment disk in the inert gas canister. 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 knee blocker airbag protective cover will split at predetermined tear seam lines concealed on the underside of the cover, then fold open and out of the way.

The cushion protects the lower extremities of the vehicle operator and helps to keep the seat occupant properly positioned for the Driver AirBag (DAB) deployment during a frontal impact collision. Following an airbag deployment, the knee blocker airbag cushion quickly deflates by venting the inert gas through the loose weave of the fabric used to construct the instrument panel side of the airbag cushion, and the deflated cushion hangs down loosely from the lower instrument panel.

Proper diagnosis of the knee blocker airbag inflator and squib circuits requires the use of a diagnostic scan tool and may also require the use of the SRS Load Tool special tool along with the appropriate Load Tool Jumpers and Adapters. Refer to the appropriate diagnostic information.