Description & Operation: Notes
The main components of SRS include: inflatable air bag/gas generator module, electronic SRS control unit, 2 crash sensors, contact ring, energy capacitor and voltage transformer (integrated into SRS control unit), SRS warning light and driver knee bolster mounted under steering column. See Fig 1 and Fig 2 .
If vehicle is equipped with passenger-side air bag, it is installed inside dash above glove box. An Emergency Tensioning Retractor (ETR) is incorporated within passenger seat belt assembly. For SRS to operate properly, 3-point seat belts MUST be worn.
The system is activated by crash sensors when vehicle's deceleration rate is equal to a direct head-on collision impact at least 12 MPH. SRS control unit then transmits a voltage signal that triggers the gas generator, igniting a solid propellant to produce a quantity of non-toxic nitrogen gas. The nitrogen gas passes through a filter to fill and deploy the air bag in about 30 milliseconds. After the air bag has inflated to maximum expansion, the gas is then released away from driver by 2 ventilation holes. The entire sequence of air bag inflation and collapse takes about 30-35 milliseconds.
Manufacturer recommends replacing air bag module, contact ring, crash sensors, SRS control unit and SRS wiring harness after air bag deployment.