Airbags. Everything we need to know about them

Airbags are a vehicle feature that we seem to overlook. Meanwhile, our life may depend on their correct action!

Although we pay attention to the number of airbags in our car when buying a car, we completely forget about them during operation. It is right? The service life of the pillows corresponds to the declared by the manufacturer? Do they require periodic review? How to check for airbags in a purchased used car? What scams do car dealers use to hide the fact of a malfunction or removal of an airbag?

In the next article, I will try to present my operational knowledge of the popular "airbags".

Air bag. How did it all start?

The history of automotive airbags dates back to the XNUMXs, when former manufacturing engineer John W. Hetrick patented the "Automotive Airbag System". Interestingly, John was inspired by a previously experienced traffic accident. In Germany around the same time, inventor Walter Linderer patents a similar system. The idea behind the operation of patented devices was similar to today's. In the event that the car came into contact with an obstacle, compressed air had to fill a bag that protected the driver from injury.

GM and Ford took care of the patents, but it quickly became clear that there were many technical problems on the way to creating an effective system - the time for filling the air bag with compressed air was too long, the collision detection system was imperfect. , and the material from which the airbag is made could cause further harm to the health of the airbag.

Only in the sixties, Allen Breed improved the system, making it electromechanical. Breed adds an effective collision sensor, pyrotechnic filler to the system, and uses a thinner cushion bag with valves to relieve pressure after the gas generator explodes. The first car sold with this system was the 1973 Oldsmobile Tornado. The 126 Mercedes W1980 was the first car to offer a seat belt and an airbag as an option. Over time, airbags have become popular. Manufacturers began to use them on a large scale. By 1992, Mercedes alone installed about a million airbags.

Air bag. How it works?

As I mentioned in the historical part, the system consists of three elements: an activation system (shock sensor, acceleration sensor and digital microprocessor system), a gas generator (includes an igniter and solid propellant) and a flexible container (the pillow itself is made of nylon-cotton or polyamide fabric with impregnation neoprene rubber). Approximately 10 milliseconds after the accident, the microprocessor activation system sends a signal to the gas generator, which begins to inflate the airbag. 40 milliseconds after the incident, the airbag is full and ready to catch the speeding body of the driver.

Air bag. System life

Given the advanced age of many vehicles equipped with the system in question, it is worth considering whether any of the components can stop obeying. Does the airbag swell over time, does the activation system break down, like any other electronic part of the car, or does the gas generator have a certain durability?

The container itself, the pillow bag, is made of very durable synthetic materials (often with an admixture of cotton), the strength of which is determined many times higher than that of the car itself. So what about the activation system itself and the gas generator? Automotive disassembly plants are most often involved in the recycling of airbags. Disposal is based on the controlled activation of the cushion.

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In informal conversations, bettors admit that old pillows are almost 100% effective. Only a few out of a hundred do not “burn out”, most often in cars with easy access to moisture. I heard the same thing in a service specializing in the replacement of car security systems. If the car was operated in normal mode, i.e. has not been filled or repaired properly, the service life of the airbags is not limited in time.

What do authorized service stations and car dealerships say about this? In the past, engineers used to give airbags a lifespan of 10 to 15 years, often attaching decals to the bodywork to indicate when the airbags were replaced. When manufacturers realized that pillows were much more durable, they abandoned these provisions. According to independent experts, such a replacement cannot be performed in vehicles with the above recommendations.

There is also another and rather marginal opinion that the abolition of the mandatory replacement of airbags is a purely marketing ploy. The manufacturer does not want to scare a potential buyer with the possible operating costs of replacing expensive components, therefore, like oils with a long service life, it eliminates the need to replace it, knowing that in ten years the responsibility for a faulty airbag will only be illusory. However, this is not confirmed in remanufactured, even very old airbags, which inflate with almost 100% efficiency.

Air bag. What happens after the “shot” of the pillow?

What should I do if an airbag deployed during an accident? How much does it cost to replace components? Unfortunately, professional repairs are not cheap. The mechanic will have to replace the gas generator bag, replace or regenerate all parts of the dashboard damaged by the explosion, and replace seat belts with pretensioners. We must not forget to replace the controller, and sometimes the airbag power supply. In an authorized service center, the cost of replacing front airbags can reach PLN 20-30 thousand. In a private professional workshop, such repairs will be estimated at several thousand zlotys.

Due to the high cost of repairs in Poland, there are "garages" that are engaged in fraud, which consists in installing dummy airbags (often in the form of rolled up newspapers) and deceiving electronics in order to get rid of unwanted system alerts. The easiest way to simulate the correct operation of the airbag lamp is to connect it to the power of the ABS lamp, oil pressure or battery charging.

After such a procedure, the airbag indicator light goes out a moment after the ignition is turned on, signaling a false system health. This scam is fairly easy to detect by connecting the car to a diagnostic computer at an authorized service center. Unfortunately, scammers use more sophisticated methods. In one of the airbag replacement workshops in Warsaw, I learned that the system that controls the operation and presence of the airbags is mainly to control the resistance of the circuit.

Fraudsters, by inserting a resistor of the appropriate rating, deceive the system, due to which even diagnostic computer control will not check for the presence of a dummy. According to the specialist, the only reliable way to check is to dismantle the dashboard and physically check the system. This is an expensive procedure, so the owner of the plant admitted that customers choose it very rarely. Therefore, the only reasonable check is an assessment of the accident-free condition, general condition of the vehicle, and possibly a reliable source for purchasing the vehicle. It is comforting that, according to information obtained from the largest car dismantling station in Warsaw, according to statistics, fewer and fewer cars that end up in a landfill have dummy airbags. Therefore, it seems that the scale of this dangerous practice is gradually beginning to be marginalized.

Air bag. Summary

In summary, according to most experts, airbags do not have a definite expiration date, so even the oldest of them, under normal driving conditions, should effectively protect us in the event of a collision. When buying a used car, in addition to assessing its accident-free condition, it is worth conducting computer diagnostics to reduce the likelihood of buying a car with a dummy airbag.

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