What Are Air Bags
An air bag is a safety feature designed to protect passengers in a head-on collision. Most cars today have driver's side airbags and many have one on the passenger side as well. Located in the steering wheel assembly on the driver's side and in the dashboard on the passenger side, the air bag device responds within milliseconds of a crash. After the initial impact, a folded nylon bag becomes rapidly inflated with nitrogen gas. This acts as a cushion for passengers, preventing them from hitting the steering column and dashboard, something that often causes traumatic injuries.How an Air Bag Works
The air bag system can be broken down into two main components. These are the impact sensor and the air bag module unit. The impact sensor does what its name implies, senses impacts. The sensors are set to a sensitivity level where they will only deploy in an accident that is equal to or greater than a 12 mph crash into a concrete wall. The sensors function by detecting automobile deceleration. When the automobile decelerates at a rapid rate, the sensors are tripped. This deceleration detecting is the job of two or more deceleration sensors, placed at the front of the car. When the sensors go off, they send an electrical current to the air bag module unit, causing it to deploy.The air bag module unit consists of an inflator assembly, a nylon bag, and a breakaway cover. This unit is typically located in the steering wheel column on the driver's side or in the dashboard on the passenger's side. The electrical current from the sensors travels to the inflator assembly, where it causes a tiny initiator to be fired. This inititator creates a spark which ignites a propellant, which in most air bags is sodium azide. The reaction creates nitrogen gas. Cinders are removed and the gas is cooled through a filtration screen also inside the assembly. The nitrogen gas is what causes the air bag to inflate. This inflation occurs in an average of only 30 milliseconds. When an occupant plunges into the air bag, the gas if forced backwards through vents, a process which takes another forty-five milliseconds. The whole sequence from initial detection of a crash, until the air bag is fuly deployed, happends very quickly. This quickness is required in order to protect those inside of the car, and was one of the major obstacles that needed to be overcome in the development of the air bag.
Comments
Post a Comment