Horizontal Load Limiting System
| ITEM | DESCRIPTION |
|---|---|
| A | Conventional steering column design |
| B | Horizontal load limiting system |
| 1 | Mismatch between direction of force and motion |
| 2 | Motion aligned to force |
The Horizontal Load Limiting System provides a progressive and stable load limiting characteristic as shown in 'B' in the illustration. Loads applied to the column cause the column to move horizontally with the driver. This movement is controlled by an energy management plate. The plate has leaves which peel back in a controlled manner, absorbing energy and allowing the column to move with the driver.
The plate is bolted to the steering column outer bracket attached to cross-car beam and the inner bracket.
PYROTECHNIC ADDITIONAL LOAD DEVICE - NORTH AMERICAN SPECIFICATION (NAS) ONLY
| ITEM | DESCRIPTION |
|---|---|
| 1 | Energy management plate |
| 2 | Pin |
| 3 | Pyrotechnic device |
| 4 | Electrical connector |
On NAS market vehicles, an additional pyrotechnic device is fitted to provide increased energy absorption to allow for a driver not wearing a seat belt. If an occupant is not wearing a seatbelt and a crash situation occurs, the device is not activated.
The pyrotechnic device is located below the energy management plate. The pin is engaged in a hole (as built) in the central leaf in the energy management plate. This provides the required energy absorption to allow for the loading caused by the unrestrained driver.
When the system detects that the driver seat belt is buckled, and a crash situation occurs which activates the airbags, the device fires, which retracts the pin. This reduces the energy absorption to a level suitable for a restrained (belted) driver.