Airbags are a safety device used in most modern vehicles. They are designed to quickly inflate in the event of a crash to prevent the drivers and passengers from colliding with objects inside the car, such as the steering wheel and dashboard. Traditionally airbags were only installed in the steering wheel and passenger dashboard, but modern vehicles may have multiple airbags located in different parts of the vehicle. It is estimated that airbags have saved many lives and prevented many injuries since they have been introduced. Many countries now require or strongly urge that airbags be installed in all modern vehicles.
What are airbags made from?
An airbag is basically a fabric bag that is designed to be strong enough to handle rapid inflation. The most common synthetic fabrics used in airbags are nylon and polyamide. The inflation of this nylon airbag occurs with nitrogen gas. For this to occur, each airbag contains a certain amount of NaN3, KNO3 and SiO2. About 40 milliseconds after a crash, 3 separate reactions take place in the airbag to produce the nitrogen gas and this inflates the bag. After deployment the airbag immediately begins deflating as gas is released through a vent.
The inflation of the airbag is controlled by an airbag control unit (ACU). The ACU monitors sensors in the vehicle and triggers the airbag in a serious crash. They are programmed with a number of settings to ensure they are only deployed when necessary and these programs are a closely guarded secret.