Many drivers are aware of the car airbag, which can escort themselves in the process of driving the car. But in fact, many people know very little about it. As one of the devices of the passive safety protection system of the car, do you know how the airbag is deployed and how it is deployed? How do airbags work? What parts does it consist of? Why do airbag explosion safety test? And why are the airbags disposable? With these questions, we will slowly come to science.
First of all, the airbag needs to be used in conjunction with the seat belt to maximize the effective protection for passengers. Under normal circumstances, the airbag will be folded in the vehicle interior, and the place where we see SRS written in the car is the place where the airbag is folded and placed. For example, the main driver's airbag is ejected from the cover of the steering wheel. Although there is no gap in the center of the steering wheel, there is actually a gap inside. This position is very thin, generally only 0.5 mm thick. Huge can easily open up this weak area.
The working principle of the airbag is: when the car collides, the collision sensor will capture the collision data and transmit the received data to the electronic controller, and then the electronic controller will analyze the data according to the collision intensity. If the condition of the airbag is satisfied, it will send an instruction to the inflation system to release the airbag, and the inflation system will be ignited, so that the high-density solid substance sodium azide or ammonium nitrate will react to generate a large amount of low-density nitrogen gas, so that the airbag will be in It expands and pops up in an instant, providing cushioning protection for passengers. The airbag just blew up.
Airbags can be divided into driver's seat airbags, passenger airbags, seat side airbags, head airbags, rear seat side airbags, seat belt airbags, knee airbags, head airbags, etc. Due to the strong impact force and the secondary damage to the human body caused by problems such as the untimely explosion time, all car manufacturers need to repeatedly and strictly do the airbag explosion test experiments. For example, the impact angle, impact position, impact strength, etc. of the collision allow the airbag to open at the appropriate time to meet the specified airbag detonation conditions. When these conditions are met, the airbag will be successfully deployed in a timely manner. Each car's airbags are determined through rigorous crash experiments and simulations time and time again.
The airbag can only be used once, after the explosion, it must be returned to the factory for a new one. This is because: First, the chemical reaction cannot be reversed. When the airbag is inflated, sodium azide, which was originally a solid substance, undergoes a chemical reaction and becomes nitrogen gas and quickly fills the airbag. In this case, it cannot reversely regenerate substances such as sodium azide. Therefore, after the airbag is detonated, the inflator is scrapped. And under such a violent collision, the flying glass fragments and broken body parts may damage the airbag. That is to say, while the airbag fulfills its mission of protecting passengers, its structure is damaged and cannot be used again. From the early use of simple cloth bags, to the high-end requirements of materials, coatings, folding methods, igniters, system integration, etc.; from the early simple actuators of airbag controllers to the later analog sensors, and now digital Sensor, the entire airbag system consists of four parts: impact sensor, electronic control system, inflation system, and airbag.
Did you get all the knowledge about the explosion of these airbags above? If you are interested in car safety related issues, you can go to the Shanghai Weitest website, which has a very detailed introduction.