Airbags are designed to protect passengers in the event of a car accident by mitigating the impact of a collision. They deploy quickly thanks to a special electronic chip capable of detecting when the vehicle suddenly stops. This chip activates an explosive that fills the airbag with gas, causing it to inflate in an instant.
What is an Airbag?
An airbag (also known as an “air cushion”) is a type of safety device that can be found in most cars today. It is a flexible fabric bag designed to inflate almost instantly in any situation where an accident occurs.
The primary purpose of an airbag is to limit the rapid movement of the vehicle occupants moving forward after the car suddenly decelerates, while also providing some cushioning effect to reduce the impact force that the occupants would otherwise experience.
The head is the most vulnerable part of the human body; thus, the primary airbag (front airbag) is installed in the steering wheel of all modern vehicles. However, there are many types of airbags, such as side airbags, knee airbags, curtain airbags, and various others.
Car airbags are an important safety feature, capable of deploying almost instantly in a collision, helping to protect drivers and passengers from serious injuries. This process occurs extremely quickly, taking only about 0.025 to 0.15 seconds, which makes many people curious about the mechanism behind it.
How Do Airbags Work?
Airbags can protect passengers and drivers from serious injuries and make the accident less harmful for those involved; but how does an airbag accurately determine the moment of deployment?
Airbags are managed by the ACU (Airbag Control Unit, a type of specialized electronic controller). The ACU also monitors a range of other sensors found in the car, including collision sensors, accelerometers, wheel speed sensors, gyroscopes, seat sensors, etc., all contributing to the deployment of the airbag in one way or another.
Like the Engine Control Unit (ECU), the Airbag Control Unit (ACU) receives signals from the sensors, analyzes the data, and makes decisions about which airbags to activate and with how much force. The ACU operates based on complex algorithms, calculating the time and force needed to protect the occupants of the vehicle in the most effective way.
When a vehicle collides with an object, it decelerates rapidly, or technically begins decelerating at a high rate, which means the deceleration will be very fast and extremely dangerous.
Upon collision, an electronic chip, known as an accelerometer, will immediately detect the sudden change in the vehicle’s speed. If this change exceeds the “deployment threshold,” the airbag circuit will be activated.
An electric current is sent through a heating element, which ignites an explosive (specifically a chemical explosive). A large amount of harmless gas is generated and instantly fills the airbag located behind the steering wheel. At this point, the plastic cover of the steering wheel ruptures and the airbag inflates (like a balloon), protecting your face!
Sodium azide is the most common explosive used in airbag systems. When the ACU sends a signal, sodium azide is ignited by a small amount of electric current, producing hot nitrogen gas at a very high speed. The pressure inside the airbag can reach up to 30 bar, equivalent to a force of 300 kg impacting one square meter. This force is strong enough to deploy the airbag instantly, protecting vehicle occupants from collisions with hard parts inside the car, such as the steering wheel, windshield, or dashboard.
As the driver is propelled forward due to sudden deceleration, the airbag will immediately inflate; however, it will gradually deflate as gas escapes through small holes around the edge of the bag. The airbag must completely deflate after the vehicle has come to a complete stop.
In reality, the entire process of airbag inflation occurs extremely quickly. On average, the entire airbag deployment process is completed in 0.120 seconds, depending on the type of vehicle and the design of the airbag.
Airbags are designed in various sizes and shapes to fit their installation locations and provide optimal protection for each seating position in the vehicle. For example, the driver’s airbag is typically larger and shaped differently compared to the passenger airbag.
To ensure optimal protection, drivers and passengers should follow these safety rules:
Always wear seat belts: Seat belts work in conjunction with airbags to provide the most effective protection for vehicle occupants.
Sit in the correct position: Adjust the seat so that the driver and passengers are seated at least 25 cm away from the airbag.
Do not place objects that obstruct the airbag: Avoid placing items such as books, bags, or toys on the seats, as they may interfere with the airbag’s operation.
Replace airbags after deployment: Airbags are designed to work effectively only once. After deployment, it is necessary to replace the airbag to ensure safety for any future collisions.
