SIR System Overview

SIR SYSTEM OVERVIEW




The supplemental inflatable restraint (SIR) system supplements the protection offered by the occupant's seat belt system (2). The SIR system may contain several inflator modules located throughout the vehicle, i.e. steering wheel module (1), instrument panel (I/P) module (1) and front seat belt pretensioners. Each inflator module and seat belt pretensioner has a deployment loop that is controlled by the sensing and diagnostic module (SDM) mounted inside the vehicle. The SDM determines the severity of a collision. When the SDM detects a collision of sufficient force it will process the information provided by the sensors to further support air bag deployment. The steering column (1) and knee bolsters (3) are designed to absorb energy and compress during frontal collisions in order to limit leg movement and decrease the chance of injury to the driver and passenger.




A frontal crash of sufficient force up to 30 degrees (a) off the longitudinal centerline of the vehicle will deploy the frontal air bags and the pretensioners.

The frontal SIR system deploys an air bag from the center of the steering wheel and from the right side of the instrument panel.

The seat belt pretensioners remove slack from the driver and passenger front seat belts during a frontal impact. The frontal SIR system may deploy the seat belt pretensioners with or without the frontal air bags.

The SDM performs continuous diagnostic monitoring of the SIR system electrical components. Upon detection of a circuit malfunction, the SDM will set a DTC and inform the driver by requesting the instrument panel cluster (IPC) to turn the AIR BAG indicator ON.