Operating process of the SRS airbag
1. The impact force generated by frontal collision is transmitted via the vehicle's structural components and input from each of the front impact sensors, the front impact G sensor and the safing drive circuit inside the SRS unit.
2. The front impact sensor converts the collision to electrical signals which are sent to the microprocessor and the safing drive circuit inside the SRS unit. At the same time, the front impact G sensor inside the SRS unit converts the collision input into waveform electrical signals and sends them to the microprocessor.
3. The microprocessor outputs actuation signals if the outputs from the front impact sensors and front impact G sensor exceed the preset threshold value. At this time, if the output from the safing drive circuit inside the SRS unit exceeds the preset threshold value, current flows through a trigger circuit, which deploys the SRS airbag and operates the seat belt tensioner and the driver's seat belt outer lap tensioner.