C 320 4MATIC Sedan (203.084) V6-3.2L (112.953) (2003)
Side Air Bag: Description and Operation
Rear Side Airbag
Purpose
The rear left/right side airbag serves to protect rear seat occupants from upper body and head injuries in the event of a side-impact collision affecting the
door, B-pillar or C-pillar areas. It is deployed at the same time as the front side airbag and the window airbag.
Design
The rear side airbags consist of a gas generator with ignition squib and airbag. The airbags consist of an uncoated, recyclable polyamide textile material.
They have a volume of 16 liters in the inflated state.
Function
Hybrid Inflator For Side Airbag
Exceeding the deployment threshold in a side-impact collision results in the deployment of the rear left side airbag (R12/11)/ rear right side airbag
(R12/12) except Model 203.7 along with the front door-mounted side airbag and the window airbag.
Operational sequence
1
When the deployment threshold for the side airbag is exceeded, the restraint systems control module (N2/7) sends an electrical trigger pulse to the
squib (4) in the hybrid gas inflator.
2
The squib then ignites the rings of solid propellant in the propellant chamber (2).
3
The solid propellant burns off and a gas evolves. This creates a high pressure in the propellant chamber which destroys the bursting diaphragm (5)
of the pressure vessel (1).
4
This allows the compressed inert gas mixture inside the pressure vessel to flow out through the discharge ports (3) into the airbag.
5
Under the pressure of the gas flowing into the bag, the bag rapidly inflates, tearing open the side airbag housing and the seam in the door lining,
and thrusting into the passenger compartment.
6
The bag reaches its full volume within approximately 20 msec.
7
The bag begins to deflate immediately after reaching its maximum volume. The gas escapes from the airbag through a filter and the airbag
collapses.