The airbag was first proposed by Hetrick in August 1953, and obtained the patent of "automobile buffer safety device" in the United States. It is a passive safety protection system, which can provide effective collision protection for passengers when used in conjunction with seat belts. When a car collides, the car airbag can reduce the head injury rate by 25% and the face injury rate by about 80%. When the collision sensor detects a collision, the relevant control system will judge the degree of collision and decide whether to trigger the inflator. Usually, the inflation module consists of a gas generator such as gasoline or explosives and an ignition device.
Yes, you are right. The airbag bounced up by explosives. Accurately speaking, the airbag does not pop up, but is instantly inflated by the explosives inside, breaking through the pre-designed weak area on the steering wheel or dashboard. You see, the dashboard in the center of the steering wheel and in front of the co-pilot is generally seamless and smooth, but there will be a carefully designed line under the smooth surface. The plastic thickness of that wire is generally only 0.5 mm, or even thinner. This is the legendary tear seam. This is also the key to airbag design. The design of this seam was determined by a lot of experiments under different conditions, and other positions were 1 to 2mm. When the airbag is ignited, the gas generator instantly releases a large amount of gas, and the airbag expands at a very high speed.
Airbag sensors are respectively installed at the left, right and middle of the cab partition; The airbag sensor and airbag system in the middle are installed together with the electronic control device. The airbag is not as comfortable as most of us think. It is like a cushion. In fact, the impact of the ejected airbag is a very painful thing, provided that the seat belt is fastened.
The airbag module is mainly composed of airbag, gas generator and igniter. The electric control device is used to collect and process data, diagnose the reliability of the airbag, ensure that the ignition signal is sent out in time when the preset value is reached, and ignite at the appropriate time to ensure that the driving gas generator has enough driving current. Airbags must be used in conjunction with seat belts to achieve maximum protection. If you don't wear a seat belt, the impact of the collision will make the human body rush forward instantly and violently explode the airbag, which is likely to bring serious damage to the weak parts or collision parts of the human body. Moreover, if there is no restraint of the seat belt, the airbag may not completely collide with the human body, and the violent deceleration of the collision may still cause the occupants in the car to be "hooked" by the airbag, continue to smash the windshield or window, and then be thrown out of the car.
When a car collides during driving, the airbag sensor first receives the collision signal, and as long as it reaches the specified strength, the sensor will act and send a signal to the electronic controller. After receiving the signal, the electronic controller compares it with the original stored signal, and if the airbag deployment condition is met, the driving circuit sends a start signal to the gas generator in the airbag module. After receiving the signal, the gas generator ignites the gas generant to generate a large amount of gas, which enters the airbag after filtering and cooling, so that the airbag can break through the buffer pad and expand rapidly in a very short time, form an elastic air cushion in front of the driver or passenger, and leak and contract in time to absorb the impact energy, thus effectively protecting the head and chest of the human body from injury or reducing the degree of injury.