Since 1995, airbags have deployed more than 800,000 times, saving more than 1,700 lives and reducing the rate of fatal injuries in car crashes by 11%. In this article, CarOn will bring readers the most basic, concise and useful information that not everyone knows about airbags – extremely important safety equipment on a modern car.
What is a car airbag?
The airbag system’s English name is Supplemental Restraint System (SRS). This is a passive device equipped on cars to limit impact and injury to the vehicle occupants when a collision occurs. According to statistics in the US, the airbag system helps limit the risk of casualties by up to 30%. When the car encounters a dangerous incident, the airbag system will inflate very quickly to form an air cushion to help reduce injury to the person sitting in the car and will quickly deflate. In some countries, airbags are considered mandatory equipment in cars in addition to seat belts.
When did car airbags appear?
The idea of shaping the bag dates back to 1919 by two British dentists named Harold Round & Arthur Parrott of Birmingham, England and was approved in 1920. And the application of air-filled air bags was officially used since 1951. .
Airbags specifically for automotive use are independently credited to American John W. Hetrick, who filed a patent application on August 5, 1952, issued by the United States Patent Office. However, his airbag design only emerged when he combined his experience working with naval torpedoes with his desire to protect his family on the road. No company invested in this great idea of his
A German engineer Walter Linderer, who filed a German patent on October 6, 1951 and was approved on August 18, 1953. Hetrick and Linderer airbags are both based on a compressed air system, released by a spring, in contact with the driver.
In 1964, a Japanese auto engineer, Yasuzaburou Kobori, began developing an airbag “safety net” system. His design harnessed an explosive to inflate airbags, for which he was later awarded patents in 14 countries.
Locations of car airbags and their effects
The airbag system is installed hiddenly in a number of locations in the compartment and chassis. According to installation location, this system usually includes 4 types: front airbags, side airbags, knee airbags, and seat belt airbags.
Front airbags
This is a common type of airbag, usually found in all types of cars. The front airbag is responsible for protecting the occupant’s head and chest before a frontal collision and is activated when the collision angle is about 30 degrees on both sides of the vehicle.
Airbags will only be activated when necessary. If the impact level is lower than the limit, the airbag will not inflate.
Rib airbags
Side airbags protect the occupant’s head and chest in the event of a side collision. There are 3 main types: curtain airbags for head-level protection, side airbags for chest-level protection, and airbags that combine both. When the vehicle body is subjected to strong impacts or the temperature in the vehicle is above 150 degrees Celsius, side airbags are used. will be activated.
Knee airbag
When the vehicle has a frontal collision, the knee airbag will be activated to protect the knee joints of the vehicle occupant.
Airbags on seat belts
The chest of the person sitting in the car always needs to be protected, the airbag on the seat belt is responsible for limiting damage to this part of the body when a collision occurs.
Structure of car airbags
The airbag system includes 3 main parts: Sensor system, detonator and airbag.
Sensor system of cars includes acceleration sensors, side pressure sensors, collision sensors, brake pressure sensors, seat sensors, and gyroscopes. All these sensors are closely connected to the airbag controller. When there is a collision, the system will activate a series of sensors to deploy airbags to help protect the driver and passengers.
Detonation part is responsible for creating gas to inflate the area inside the airbag and detonate when an impact occurs to ensure driver safety.
Air bag Made of high-strength fabrics with good elasticity and neatly folded and placed in the airbag positions. Most vehicles have airbags in the front of the dashboard, and many also have airbags along the side of the vehicle. These bags are compressed and kept in a small area. During an accident, the airbag fills with air very quickly to create a cushioning system for the vehicle occupants to protect them from being thrown out in the event of a collision.
Principle of operation
When the vehicle collides, the sensors will transmit signals to the ECU. If the collision exceeds the specified value, the ECU will transmit a signal allowing the airbag detonator to operate. At this point, the detonator will ignite the igniter, creating a large amount of gas that will inflate the air bag.
Previously, car airbags used to be inflated with compressed air. However, manufacturers found it did not work effectively. Therefore, it was later replaced by a sodium chemical reaction, meaning that when charged, it will inflate the air bag in a very short time (about 30 ml/s).
When receiving an activation command from the ECU controller, the igniter is burned, producing Hydrogen and Oxygen gas. At this time, a large amount of air is produced in a narrow area, forcing the air bag to inflate.
Why do we need airbags when we already have seat belts?
When a car crashes into another car or a fixed object, it stops very quickly but not immediately.
For example, if the front of the vehicle crashes into a fixed barrier or the rear of a stationary vehicle at a speed of 50 km/h, the vehicle will only stop completely after about 0.1 seconds. At the moment of impact, the front part of the car stopped suddenly but the rest continued to move at a speed of 50 km/h due to inertial force. (cabin compartment is also among them).
During the impact, the cabin begins to decelerate, but the passenger continues to move forward at the same speed as the initial speed in the cabin. Without protective equipment, they will continue to move at a speed of 50 km/h until they collide with objects in the car (front glass, dashboard, etc.) – this speed is equivalent to being hit. fell from the 3rd floor to the ground. Furthermore, with strong impacts (at speeds above 20 km/h), seat belts cannot guarantee 100% of their protection and impact resistance. Passengers can still hit objects in the car, just with less force.
From that basis, air bag was born to Combined with seat belt helps further reduce the possibility of impact of the face and head with objects in the vehicle and absorbs part of the impact force from the driver and passengers.
Notes when using airbag systems in cars
– When the airbag explodes, it will be very fast and create very strong force. Do not leave or install any additional items on the airbag system of the driver and front passenger. Leaving or installing additional items can cause injury to passengers when the airbag operates.
– After the air bag explodes, it will emit a large amount of heat. Therefore, absolutely do not touch the parts inside the airbag after it explodes, this will cause burns.
– Children under 12 years old should not sit in the front row, this is very dangerous if a collision occurs. The belt system does not have enough traction to operate, while the airbag’s explosive force is very strong and can cause serious injury to the child.
The above article hopes to give readers an overview of car airbags – one of the indispensable devices in cars today.
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