It is a Passive Safety vehicle device, consisting of a flexible fabric cushion which is designed to inflate rapidly during the occurrence of an automobile collision.
When a car travels at about 60km/hr speed, it has the tendency to move in the same direction and speed until some opposite force acts on it. In a moving car, along with the car, the occupants would also travel in the same speed as that of a car. However the inertia of the occupants were independent of the car, when a car is set to crash with a pole or a tree, then the inertia or the momentum of the car will be stopped abruptly, but still the occupant’s inertia will force them to hit the steering wheel or dashboard or windshield of the car body. This would result in damage to occupants face, head or sometime in worst case it would cost a life.
So the Car manufacturers have decided to develop two different restraint systems, Airbags and Seat belt tensioner. Purpose of the seat belt tensioner is that, as soon as the crash is happened, the occupant’s seat belt will be pre-tensioned to hold the occupants intact with the seat thus it will result to reduction of some sort of damage.
On the other hand the ultimate aim of the airbag is to cushion the bodies and protect them from being hit to the interior objects of an automobile, such as Steering wheel, dashboard and front mirrors.
In the present advancement of technology we have a maximum of 10 airbags (in Mercedes Maybach), which can protect the Driver & Passengers from various impacts. Provided, the driver and passengers were correctly restrained with seat belt and other mandatory conditions such as child seat and so on.
Airbag Control System:
It is a passive restraint system (since it operates after an action is happened) which determines the crashes and deploy Airbags, thus preventing loss of human life in crash situations.
An electronic control unit processes a signal from an Acceleration sensor and based on an algorithm, deploys the airbags with the use of Pyrotechnical Generators.
Some of the Pre-Requisites:
1.Driver & Passenger needs to wear the Seat Belt.
2.Passengers should be in seating positions.
3.Not too many passengers in the car.
4.No child seats in the front (Facing the Rear).
Other safety concerns: It’s most important to take care that, the force of an airbag will hurt for those who were very nearer to the Airbag. It has been found by research that the occupant will be in risk zone, if he sits 5 to 8cm of inflation. So the occupant should be placed at a distance of 25cm from the inflation which would results in a high safety.
So always keep in mind that you are seated at the safe zone, by measuring the distance between the Steering wheel and your breast bone. You can move the seat backwards in a way that you have placed your feet comfortably on the pedals. Also point the center of the steering wheel to your breast bone and not your face.
Working of Airbag:
There are three parts of an airbag system that helps to accomplish the Passenger Protection
1.The Airbag, which is made of a thin nylon fabric, which is folded and placed inside the center of the steering wheel or most recently in seat or door.
2. The Sensor, which tells the device when to inflate the airbag. Deployment will happen when a collision force which is equal to running into a brick wall at 16 to 24 km/hr speed. Sensors will detect the crash using the switch which gets contacted during the mass shifts. Mostly the sensors which were used is Accelerometer sensors in front of the Cars bumper.
3.The Nitrogen Gas, which is used to rapidly inflate the airbag soon when it receives the Go signal from the control unit. The nitrogen gas which is used to inflate the airbag is obtained from the chemical reaction of Sodium Azide and Potassium Nitrate.
Example of a Modern Restraint System:
A typical restraint system is shown above with, Front Airbags, Side Airbags, Curtain Airbags and Rollover protection.
Statistics of Airbag (The Life Saver):
Between 1987 and 2000, around 6553 lives were saved by the airbags (in US alone). In 2000, more than 100 million airbags equipped passenger vehicles were on road. Significant reduction of serious injuries to Face, Head, Chest and Knee were achieved through this airbag.
Over 200 million cars and trucks on U.S. roads have Driver Airbags. And over 140 million of these were also have passenger airbags. Another 1 million new vehicles with airbags are being sold for every month. The NHTSA have estimated that around 18,319 people were survived because of airbags.
After the airbags arrival, the death tolls in frontal crashes are reduced about 26% with drivers using seat belts and 14% with right front passengers using seat belts. Also the NHTSA have predicted that a combined Airbag & Seat belt will reduce the risk of serious head injury.
Future of Airbags:
The NHTSA have triggered for a some improved dummies injury criteria on the knowledge, research and previous collision data’s. Till now most of the Car manufacturers have given importance to the Frontal collision, even though 40% of the serious injuries happen because of side impact and 30% due side impact collision. Now this has been taken up as a challenge by the car manufacturers. As a result of which, the car doors were made thicker
Engineers have said that, designing an effective side airbag is far more difficult than designing as effective frontal airbag, this is due to the luxury of time offered during the frontal crash. The algorithm has got 30 to 40 milliseconds to decide & deploy the airbags in frontal crash, but in side crash, the algorithm has got only 5 to 6 milliseconds to make a decision & to deploy the airbag.
All this has proved that airbags development is still new and under rapid development. You can expect much advancement from the engineers.
This is a very good resource and it is very important for everyone to note the details in this articles. It saves lifes and prevent injuries during accident while driving.
I will particularly take note of everything discussed here.
Thanks for your comments!... This is a life saving feature, and it will be made as a regulation soon in India.