An Examination of the Technology that Makes Airbags Deploy so Rapidly
It’s a little known fact that airbags are actually not a new idea, and some may be astounded to realise the design has been around for over 60 years. The very first patent on an airbag for air planes was lodged during World War 2. In the 80s, the first commercial airbags were present in vehicles.
Up to the present day, statistics indicate that air bags reduce the possibility of dying in a square head-on crash by around 30%. These days we also have door mounted side and seat-mounted airbags. As a matter of fact, some cars go way further than just having dual airbags, and instead have six to eight airbags.
The task of an air bag is to decelerate the passenger/driver’s forward movement as evenly as possible in just a split second. An air bag can accomplish this task in three steps:
- The bag itself is made of a thin, nylon fabric, which is compressed into the steering wheel or dashboard and, more recently, the seat or door
- The detector is the device that instructs the bag to inflate. Ballooning happens when there is a smash force equal to motoring into a wall at around 15 miles an hour. A mechanical switch is flicked when there is a weight shift that cuts off an electric contact, notifying the detectors that a smash has taken place. The detectors receive data from an accelerometer that’s part of a microprocessor chip
- The bag’s inflation facility reacts sodium azide (NaN3) with potassium nitrate (KNO3) to develop nitrogen gas. Hot blasts of the gas inflate the airbag
Because of the incredibly fast inflation of an air bag, it’s essential the driver and passenger sit in the seat with a straight back providing a good space between their face and the dashboard / steering wheel - this provides time for the bag to expand while the passenger/driver are being pushed forward by the shock of the smash.
