A Softer Impact: the Airbag’s Role in Car Safety
Few individuals realise that the concept of the air bag – a soft cushion to impact against in a crash – has been around for many years. The very first patent on an airbag for air planes was lodged during World War II. During the 80s, the first commercial airbags were a safety feature in vehicles.
To date, stats indicate that air bags cut back the chance of dying in a direct anterior crash by as much as 30%. These days there are also door-mounted side and seat-mounted air bags. Incredibly, some automobiles go far beyond just having two air bags, and instead have six to eight airbags.
An airbag’s task is to slow down the advanced motion of the driver in just a fraction of a second. There are 3 components to an air bag that help execute this feat:
- The bag is composed of a thin, nylon fabric, which is folded inside the dashboard or steering wheel and, more recently, the seat or door
- The sensor is the gadget that tells the airbag to balloon. Expansion happens when there is a smash force equating to motoring into a brick wall at 16 to 24 km per hour. A mechanical switch is flicked when there’s a weight shift that cuts off an electric contact, instructing the sensors that a crash has happened. The sensors get information from an accelerometer built into a silicon chip
- The bag’s expansion facility fuses sodium azide with potassium nitrate (KNO3) to make nitrogen gas. Hot blasts of the nitrogen balloon the air bag
Because of the superfast expansion of an air bag, it’s a safety requirement that the driver and passenger sit in an upright position providing a safe space between the steering wheel / dashboard and their face – this leaves time for the airbag to expand while the passenger/driver are being thrust forward by the shock of the accident.
