What are the components of an airbag?
The airbag system consists of: collision sensors, an ECU (Electronic Control Unit), a gas generator, and the airbag itself.
Airbag sensors: Also known as collision sensors, collision sensors are categorized into trigger collision sensors and protective collision sensors based on their application. The driver-side airbag is located in the steering wheel; the passenger-side airbag is typically mounted on the dashboard. Airbag sensors are installed on the left, right, and center of the passenger compartment partition; the center airbag sensor and airbag system are integrated with the electronic control unit. The airbag assembly mainly consists of the airbag, gas generator, and igniter.
How a car airbag works: During airbag operation, when a collision of a certain intensity occurs while the car is in motion, the sensor switch is activated, the control circuit begins to operate, and then the detection circuit determines whether a collision has actually occurred. If signals come from two sensors simultaneously, the airbag will be activated.
Because the car’s alternator and battery are usually located in vulnerable areas at the front of the car, the airbag control system has its own power supply to ensure its function. After confirming that the conditions for airbag deployment are correct, the control circuit sends current to the igniter, which then heats up rapidly to ignite the contained sodium nitride propellant.
According to calculations, a conventional airbag must activate within 0.01 seconds of a car collision, the ignition must start within 0.03 seconds, high-pressure gas must enter the airbag within 0.05 seconds, the airbag must inflate outwards within 0.08 seconds, and the airbag must fully inflate within 0.11 seconds. Only then will the driver hit the airbag. Passengers contact and press the airbag to achieve safety protection; through the viscous damping effect of the gas, the forward energy of the occupant is absorbed and dissipated, and the overpressure gas inside the airbag is discharged through the airbag vents without causing injury to the occupant.
What are the classifications of airbags?
- According to the number of airbags: Single airbag system (only installed on the driver’s side), dual airbag system (one airbag on the driver’s side and one on the front passenger side), and multi-airbag system (front airbag, rear airbag, and side airbags).
According to size, airbags can be divided into: large airbags that protect the whole body, large airbags that protect the entire upper body, and small face airbags that primarily protect the face.
According to the objects they protect, airbags are divided into: driver’s side airbags, front passenger side airbags, rear passenger side airbags, and side impact airbags.
Airbags deploy immediately upon impact to cushion the impact and protect the driver and passengers. Typically, in a collision, they prevent the occupants’ heads and bodies from directly impacting the vehicle’s interior, thus reducing the severity of injuries. According to a study by the National Highway Traffic Safety Administration (NHTSA) in the United States, proper use of airbags can reduce the fatality rate for car drivers by 11% and reduce the impact force of frontal collisions by 30%. If the airbag system malfunctions, a specialized OBD2 airbag scanner can be used to read the SRS fault codes.