Airbags, the Lives Savior

Traffic accidents are currently the number one contributor to the world's highest death. Driving a vehicle in high speed make the drivers do not realize that to run fast requires a vehicle that is safe, especially if there is an unexpected accident. No wonder if the modern vehicle manufacturers began to equip their vehicles with safety features in addition to the seat belt, the air bag.

Statistics show that the use of seat belts and the airbags existence has saved thousands of lives that might have been lost in accidents. Until now, several data indicate that airbags reduce the death risk in a direct frontal crash about 30 percent.

The concept of airbag became a cushion which was inflates when a collision happen has been there since many years ago. The airbag idea takes the concept of an airplanes inflatable crash-landing device that used in World War II. Originally airbag system is designed to be used as a substitute for seat belts. Ford had used it in 1970, but the first commercial airbags used on automobiles that produced in 1980. Widespread usage and then directly applied in the United States where all the new cars mandatory equipped with airbags in 1998.

At first airbag only used for the driver and it stored in the steering wheel. Along with the increased security, airbag also placed for passengers on the front seat, back seat, also at the door in anticipation of a side collision. For some manufacturers, the airbag has a variety of technical names like Supplementary Restraint System (SRS), Air Cushion Restraint System (ACRS), and Supplemental Inflatable Restraint (SIR).

The airbags protects the head, neck, and chest, during an impact from the front and later the airbag inflates in a few milliseconds. There are three main components in the airbag system are bags, sensors, and inflation systems. The air bag material using nylon material that is folded into the steering wheel, dashboard, door panels, as well as some mounted on the roof and on the doors. Then the sensor as a mechanism that will provide information on when the bags must inflate. When it detects a collision, sensors on the car sends a signal to the control module that will make the airbag inflates.

The basics of airbag inflation. (Left) An undeployed airbag is folded within a car's steering wheel, its sodium azide–containing inflator attached to the crash sensor in the steering column. (Right) Activated by a crash (arrows), the sensor triggers the inflator to produce an electric spark that ignites the sodium azide, which rapidly produces nitrogen gas that inflates the airbag. (Picture from: http://www.lanl.gov/)

On the first model of airbags which was placing a sensor on the front of the car. In the new model, sensors mounted directly on the airbag module so the sensor also serves to measure the speed and extent of damage in a collision. There are also sensors placed on the door to activate the side airbag. Airbags are mounted on the dashboard or the steering wheel will only inflate in case of front collision or in the area of ​​30 degrees from the front of the car.

Then the airbag inflation system is usually using combination of potassium nitrate (KNO3) and sodium azide (NaN3). Both of these substances will form nitrogen gas. This gas will inflating the bag with a speed of about 321 kph. After inflation, the gas spread through the small holes in the airbag is causing it to deflate. The whole process takes about 1/25 sec. Although increasingly sophisticated airbags and also as the standard feature for modern vehicles, I think you should never use it. *** [EKA | FROM VARIOUS SOURCES | DOE | PIKIRAN RAKYAT 02082013]

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