Ever Wondered how airbags work?

No one would ever want anything to blow up in their face under any circumstance, but the one time an explosion might actually save your life is the blowing up of the airbags during an accident. Forty milliseconds is all it takes for the airbag to be fully blown from the first impact. Airbags are a very major safety component of vehicles but still hasn't become part of standard equipment in all cars yet. But have you ever wondered how airbags work?

When a vehicle crashes the people occupying the front seats face around 30 G's of force at a speed of around 50Kmph. During the event of a crash, the vehicle decelerates almost immediately upon impact but the passengers inside do not decelerate at the same rate due to the change in momentum. It is similar to the case of getting out of a moving bus, where the person will tend to move forward in the direction of the motion due to the inertia of motion. So at the point of impact, the people inside will move forward, which will cause a direct impact on the steering wheel or the dashboard of the car which can be fatal at such high speeds. 

An airbag does not just act as a pillow but actually helps in the deceleration of the occupants of the car in a faster and smoother way. An airbag system consists of multiple accelerometers and a gyroscope that constantly monitor the acceleration and deceleration rates of the vehicle and upon rapid deceleration, these accelerometers will send signals to an airbag control module which will decide if the deployment is required or not. There are other crash sensors too surrounding the vehicle. When airbag deployment is not required, the locking up of the seat belt is the only safety measure operated. If the module decides the airbag must be released, at the time of seat belt lockup, a signal is sent to the airbag inflator. The airbag inflator essentially heats a canister containing sodium azide, a chemical that on heating gives large amounts of nitrogen gases and sodium. This nitrogen fills up the airbags, that deploys the airbags at speeds between 150-200 miles an hour.

You might have also noticed that by the time the people are evacuated from the car the airbags are fully deflated. What you don't know is that the airbags start deflating as soon as they are inflated which is what aids in smoothening the deceleration of the person providing a cushioning effect. 

But just an airbag is not enough too. With the person accelerating forward, and the airbag accelerating in the opposite direction and towards the person, the impact can be very painful. This is where seatbelts play a very important role. The locking up of the seat belt upon sudden hard braking is a major component of the deceleration of the person on impact.   In a few vehicles, engaged seat belts is a mechanism of turning on the airbag system too. 

So with responsible driving and a locked-in seatbelt, your car is a much safer place for you;)