The invention of airbags have revolutionized the attempts to provide safety to the car passengers during a crash. Airbags are capable of protecting the occupants by acting as cushions during an impact. But the technology behind the working of an airbag still seems to be in its infancy. Incidences of accidental deployment of airbags have killed substantial number of people. Also, most mishaps occurred when the airbags failed to deploy during the crash and deployed at some other time. Though, this can be largely attributed to the system errors, human intervention is also responsible to a great extent. In this article, we have presented a few causes of accidental deployment of airbag, as well as a few precautionary measures to avoid mishaps. But before that, it would be interesting to know the working of an airbag deployment system.
Working of an Airbag
Airbag system is made up of three components - crash sensors, diagnostic module and airbag module. Crash sensors sense a series of forces such, such as inertial and gravitational force along with the sudden deceleration of the car. They break the electrical circuit when they detect that the impact of forces is such that it warrants the deployment of airbags. The diagnostic module is responsible for constantly monitoring the electrical circuits, and controlling the operation of the indicator lamp that detects the fault in the system. It is also responsible for storing and recording diagnostic information, and for supplying back- up power when the battery of the vehicle is low on power or damaged.
The airbag module is the visible module which consists of a baseplate and cushioning components. Air bags use a pyrotechnic device for inflation. This device uses the current (approximately 750ma) for energizing an igniter which initiates the combustion of sodium azide pellets to create nitrogen gas for filling airbags. For deployment of an airbag certain criteria must be met. A vehicle is subjected to various forces during a crash, if this forces exceed the threshold limit, they trigger the inflation of airbags. The speed of inflation of airbags is about 250 mph and the deployment is completed in less than a second.
Causes for Accidental Airbag Deployment
The primary cause is faulty working of some on board computer. There are about hundreds of on board computers installed in advanced cars. Thus, you can imagine the probability of something going wrong with any of these computers. Besides, the installation of after market equipment tends to interfere with the deployment mechanism of the airbag. Many car owners clutter the area around airbags with mobile phone chargers, i-pod docking stations and other such equipment. This is highly risky as it can interfere with the signals of sensor, and can cause accidental deployment of an airbag. In addition, certain seemingly harmless actions such as slamming a car door, hitting a pot hole or taking a turn too fast can also activate airbag deployment system. Also, certain environmental factors like dust, moisture can trigger the chances of accidental deployment of airbags.
How to Avoid Accidental Airbag Deployment
Visit a specialized technician for any problem concerning the electrical circuitry around airbag deployment system. If you intend to do it on your own, make sure you follow the guidelines below for safe functioning of airbag deployment system.
- Do not undertake any electrical operation without deactivating the battery.
- The deactivation should be done as per the manufacturer's instructions only.
- Do not clutter the area near dashboard and airbags with unnecessary electronic devices.
- Avoid driving vehicle in wet, dusty conditions for too long.
- Routinely check for faulty, outdated parts and replace them with new factory parts.
- Get the computerized test done to check if the airbag system is working properly.
Apart from taking the above precautions you should also strictly adhere to the safety recommendations given by NHTSA, which include:
- Never allow children, infants or senior citizens to ride in the front seat. Install a child seat at the back, preferably in the middle.
- Drivers should sit at a safe distance (about 10 inches) from the center of the steering wheel.
- Wear your shoulder harness and lap belts. This reduces the risk of serious head injury in a crash by 85 percent.
- Most airbag systems come with an ON/OFF mechanism, however if your car doesn't have one, you can install it only if you are not able to adhere to the above recommendations.
The technology of airbag system is still evolving. Safer airbags, which will take into account various factors like the weight of the occupant, vehicle speed, seat belt use, seat position etc. are under-way. They will be greatly beneficial to children and adults of small stature.