Main/passenger seat airbag

[WapCar] Airbag (or Supplementary Restraint System, abbreviation: SRS) refers to the inflatable soft bag installed on the car, which consists of the airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor.  The purpose of airbags is to provide soft cushioning and restraint to vehicle occupants during a car collision. Generally speaking, in the event of a collision, the head and body of the occupant can be prevented from directly hitting the interior of the vehicle, reducing the injury between the floating occupant and the interior of the vehicle.

Airbags have been specified as one of the necessary passive safety devices for vehicles by most countries.

The main/passenger seat airbag, as the name suggests, is a passive safety configuration to protect the front passenger, and is often placed in the center of the steering wheel and above the driving glove box.

Working Principle of Airbag

Its working process is actually very similar to the principle of a bomb: when a collision occurs, the vehicle’s collision sensor will provide important information to the airbag electronic controller (ECU). Using this information, the airbag ECU’s collision algorithm determines whether the collision event meets the deployment requirement. Standard, and trigger various trigger circuits to deploy the airbag module in the vehicle. The gas generator of the airbag is equipped with "explosives" such as sodium azide (NaN3) or ammonium nitrate (NH4NO3). When receiving the detonation signal, it will instantly generate a large amount of ammonia gas, filling the entire airbag.

According to statistics, most of the collision accidents are low-level collisions, but because the energy released at the moment of the airbag explosion is very large, when the collision is not too serious and the airbag ejection conditions are reached, the strength of the airbag may Increased harm to the human body? In 1999, the BMW 5 Series was equipped with an airbag with a secondary gas generator developed by TRW. This kind of airbag improved the protection effect of the airbag to a certain extent, and is now popularized by global car companies.

The so-called two-stage gas generator is similar to the multi-stage thruster when the rocket ascends to the sky. In the event of a relatively low-level collision, only the first-stage gas generator ignites, which allows the airbag to "softer" cushion the contact with the human body; when a serious collision is detected, the second stage gas generator will start. Usually the second stage will delay detonation after the first stage is ignited. Relying on the control of the detonation timing, a better cushioning effect can be achieved (generally a few delays Between ten milliseconds and more than one hundred milliseconds, the delay time depends on the degree of collision).

Even if the timing of airbag control is appropriate, in the event of a collision, airbag alone cannot effectively reduce injuries. The reason is that if an accident occurs, the airbag may cause more serious injury to the occupants of the car without the restraint of the seat belt. Therefore, seat belts and airbags cooperate with each other to reduce the damage to the occupants in the accident.

Development History

In 1952, inspired by a traffic accident, American engineer John W. Hetrick began to study airbags. On August 18, 1953, it obtained the U.S. Supplementary Restraint System (SRS) patent.

In 1964, Japanese automotive engineer Yasuzaburou Kobori began to develop an airbag "safety net" system. His design used explosives to inflate the airbag.

In the early 1970s, General Motors began to provide cars equipped with airbags.

In December 1980, the Mercedes-Benz S series became the first car equipped with airbags to be officially sold in Europe. In 1988, Chrysler began to install auxiliary airbags on all its models, and made a major TV commercial to demonstrate the effectiveness of auxiliary airbags, which truly opened up the competition in the automotive industry for safety equipment.

Precautions For Use

1、Airbags must be used together with seat belts to ensure that the degree of injury in a collision is reduced;

2、Keep a proper distance from the airbag when riding;

3、Do not place objects in front of, above or near the airbag, because these objects may prevent the airbag from inflating or be thrown out in an emergency, causing greater danger;

4、Do not change the airbag system and surrounding layout without authorization, do not change the circuit and components of the system without authorization, do not change the bumper and the front structure of the vehicle at will;

5、The airbag is a one-time product and must be returned to the factory for a new one after detonation;

6、For vehicles with airbags in the front passenger position, children cannot sit in the front row or place child seats in this position. Unless the airbag in this position can be manually turned off, the airbag will cause great harm to the child when it detonates.