Airbags constitute, together with safety belts, the most important parts of the restraint system available to passengers in both motor vehicles and aircrafts. A defective airbag in a car could potentially have tragic consequences. An airbag, which is also known in passenger cars as a SRS (Supplemental Restraint System), is a synthetic material bag that, within milliseconds of a collision, expands and inflates, cushioning, in doing so, the passengers from impacts against the steering wheel and the dashboard. The inventor of this device, Walter Linderer from the city of Munich, had registered a patent for it already back in 1951. Front, side and head airbags have, meanwhile, become standard equipment in automobiles.
Airbag functioning
An airbag system consists of a nylon bag, an inflator, a control unit, and sensors. There are several sensors, which are built in the control unit and also located inside the vehicle compartment itself. Pressure sensors are to be found in the door, and seat position sensors are fitted to the driver’s seat and in the seat harness buckles. Acceleration sensors, which are independent one from the other, also trigger off the inflating of the airbags. The control unit is responsible for the matching of the sensors’ data, which can still be transmitted even when the contact to the vehicle’s battery has been cut due to an accident.
Generators can be classified as pyrotechnic, cold gas, or hybrid gas sorts. In the case of a pyrotechnic generator, an ignition unit is activated by an impulse generated by a control device, which leads to the combustion of a solid fuel propellant. The hot gases released through this process fill up the airbag. In the case of a cold gas generator, the gas is stored by being compressed under great pressure. When the airbag inflates, the compression chamber bursts and the gas flows into the air cushion. Hybrid gas generators possess a gas storing chamber as well as a pyrotechnic initiator, which are used to release the gas.
Different types of airbags
The front airbag is one of the most important types available in the airbag system. It is located in the middle of the steering wheel, just above the glove compartment. It expands and inflates only 15 milliseconds after a collision, reaching its full expansion span after 50 milliseconds. After 150 milliseconds it is completely flat again, with no chance of its inflating again. Drivers’ airbags have a volume capacity of 45-60 litres, while passenger air bags have one of 80-120 litres. Further airbag types such as side airbags, head airbags, and “curtain” airbags which drop down are available, together with knee airbags, and a range of inflatable protective air cushions such as those for backseat passengers, or those to protect the torso. Cars, such as Volvo V40, offer a pedestrian airbag, (for the protection of pedestrians if they are hit), which is located at the lower end of the windscreen.
Injuries caused by airbags
Injuries that are provoked by airbags can come in the form of light burns, hearing damage, and dermabrasions. Besides, it is possible that asthma sufferers may experience temporary complaints. Infants who are being transported in back-facing baby car seats (baby carriers), are not allowed to sit at the front if there is an active passenger airbag there. In fact, in case of a collision, they might be lethally injured by the airbag‘s inflating.
If the warning light comes on
If the warning light comes on for longer than 4 seconds, it flashes or it simply stays on, it could mean that that the airbag is faulty. It could also be that the seatbelt tensioner is malfunctioning. Swapping an airbag may cost up to 6,000 Dirhams, but it is necessary to have it done in order to get your car registration renewed. In the UAE, a car must undergo a regular mandatory general technical inspection (e.g. done by Tasjeel or Al Shamil). Fitting in and taking off of airbags may only be carried out by a specially trained technician.