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Home >> BMW >> 2002 >> 745Li >> Repair and Diagnosis >> Restraints >> Restraints Control Systems >> Intelligent Safety Integration System - Overview >> Intelligent Safety Integration System (ISIS) >> System Overview >> Advanced Head Protection System (AHPS) >> Operation
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Advanced Head Protection System (AHPS): Operation

The Advanced HPS is fitted in the roof zone. It consists of a woven tube with an additional curtain wrapped around it. The curtain is secured to the roof frame and is tensioned downward by the woven tube.

Fig 1: Identifying Gas Generator For AHPS I And II
G03391550Courtesy of BMW OF NORTH AMERICA, INC.

In the event of a side collision, the generator is ignited and the gas flows through the gas injector into the woven tube. The woven tube expands to approx. 130 mm in diameter and its length is reduced.

Secure fitting of the woven tube on the A-pillar and the C-pillar HPS II or on the roof frame (AHPS I) brings the head airbag into position. In the process, the curtain tightens between the side window or pillar trim and the occupant.

The high tensioning force in the woven tube pulls the curtain downward, which increases the stability of the curtain. The closed system means that the structural firmness and stability remain for several seconds. This is an advantage if the vehicle rolls over.