Air Bag Systems: Description and Operation: Overview
DESCRIPTION AND OPERATIONFrontal Impact Area:
The air bag supplementary restraint system (SRS) is a safety device which, when used in conjunction with the seat belt, is designed to protect the driver and front passenger by operating when the vehicle receives a frontal impact (in the area shown) exceeding a certain set speed.
In the event of a frontal impact, when the air bag diagnostic control unit and one of the air bag crash sensors senses the impact, the diagnostic control unit triggers the air bag modules which fires an igniter. This in turn ignites tablets of sodium azide which generate a large amount of Nitrogen gas leading to air bag inflation in approximately 30 milli-seconds.
When fully deployed the air bag offers additional protection to the front seat occupant. As an occupant moves into the air bag it immediately discharges the gas from vent holes to provide progressive deceleration and reduce risk of injuries. The whole process is completed in approximately 0.3 seconds.