The airbag deployment system is a very important safety component in modern vehicles. Airbag deployment system is a system to protect passengers in case of a vehicle collision during travel. If a collision occurs during the journey, the airbag deployment system is detected by sensors and deploys to help the occupants avoid injury from the collision. In this article we will learn about how do Airbags Work in detail.
How Do Airbags Work?
Air bag deployment system consists of many subtle parts like airbag, controller module, sensor system, etc. So let’s study each part in detail
(1) Crash Sensors :
Crash sensors are placed throughout the vehicle designed to service changes from sudden increases in vehicle speed or sudden to extreme decreases in vehicle speed. These crash sensors measure the force and direction of the impact and provide this information to the control module.
(2) Control Module :
The control module is known as the brain of the airbag deployment system. It receives the signal from the crash sensor whether a collision has occurred and decides whether the air bag needs to deploy or not. The control module takes into account various factors such as the severity of the collision, the position of the passengers and the use of seat belts. Considering all such forces, the controller module decides whether the air bag needs to be deployed or not.
(3) Airbag :
An air bag is a positioning balloon-like bag placed inside the vehicle in the steering wheel, in the seat and inside the dashboard. In the event of a collision, the air bag acts as a cushion to help reduce the risk of injury to the occupants. A signal to rapidly inflate the bag with gas is received by the controller module. Once the air bag is deployed it completely surrounds and protects the occupants.
So let us now look at the various events that take place during a collision and how the air bag deployment system works.
How the air bag deployment system works?
(1) Collision Detection :
A crash sensor detects a sudden increase in speed or a sudden decrease in speed when a collision occurs. These crash sensors send signals to the vehicle’s collision controller module.
(2) Signal Processing :
The controller module receives the signal sent by the crash sensors and analyzes the data received by it to determine the severity of the collision. It decides whether to deploy the air bag or not based on a highly sophisticated algorithm and pre-programmed limits.
(3) Deployment Decision :
After analyzing the data the controller module decides whether to deploy the air bag or not. For that he takes the final decision considering various factors like severity of collision, position of passengers, position of seat belt etc. Considering all these factors, if the controller module detects the need to open the air bag, it takes the next step.
(4) Gas Generation :
Once the controller module makes the final decision it sends a signal to the inflator module. The inflator module contains a mixture of chemicals that include sodium azide and potassium nitrate. As soon as the inflator module receives the signal, it mixes these two chemicals to produce nitrogen gas in very large quantities and very quickly.
(5) Airbag Inflation :
The gas produced by the inflator module enters the air bag through the filter to inflate the air bag. This process is very fast which takes place within a fraction of a second. Fully inflated bags act as cushioning and reduce the risk of injury to passengers during a collision.
(6) Occupant Protection :
The air bag, which is quickly fully inflated with gas, deploys towards the occupants of the vehicle and acts as a means of protection between the occupants and the hard surface of the vehicle interior. In a collision, the passenger’s head, chest or any part of the body avoids hitting the windshield or any other hard surface. Air bags also protect passengers from being ejected from the vehicle.
Thus, air bags are an important safety feature in today's modern vehicles and they actually help the passengers to avoid serious accidents many times.
At what speed do airbags open?
If the passenger is not wearing a seat belt while traveling and if a collision occurs, the air bag deploys at high speed in 10-12 mph. If the passenger is wearing a seat belt during the collision, it opens in 16 mph because the seat belt itself also works as a safety device.
Which gas is used in airbags of car?
Generally Sodium Azide is used in airbags. Electric charge triggered by the car causes Sodium Azide to breaks down. Sodiun Azide is very sensitive to electric charge or physical shock. As Sodium Azide breaks down it creates Nitrogen Gas in tremendous amount. This Nitrogen Gas fills the AirBag rapidly.