Curtain airbags have proven to be very efficient in side-impact collisions. However, so far it has not been possible to use them in convertibles, since curtain airbags are deployed from the roof.Currently, many convertible vehicles use “combo bags” for side-impact protection. These are chest bags with an extension that inflates upwards to protect the head. But the extension could be wobbly since it – unlike a curtain airbag – is not attached to any roof pillars. There is also a risk that the occupant’s head misses or slides off the relatively narrow head extension of the combo bag. To address these drawbacks we are developing a specially designed door-mounted airbag. It is made up of a multitude of small cells (like a beehive) in three layers. This ingenious structure gives it unsurpassed stability in addition to the necessary cushioning capabilities. As a result, the new airbag will not only be used in side-impact collisions but also in rollovers, because the inflated structure will be strong enough to keep occupants in the car in many such crashes. The three layers of cells are manufactured by our weaving company near Manchester, U.K., using Autoliv’s patented one-piece weaving technology.
To date, driver airbags have had to be round and symmetrical. The top of the bag should protect the occupant’s head as well as the abdomen and chest, whether the wheel is turned or not. However, the head and the chest have different weights and are at different distances to the bag. Consequently, neither the top nor the bottom of a driver airbag can be optimized for just one body part, unlike passenger bags which are fixed and can be rec-tangular. To address this situation, we have developed a steering wheel with a fixed hub. As a result, future driver airbags can even be designed with an appendix airbag that prevents the driver from hitting the windshield pillar in oblique crashes. The fixed-hub steering wheel also eliminates the need for a connecting coil. Without this mechanism, the wires to the horn and the other controls on the steering wheel would wear out due to the constant turning during the life of the vehicle. Now, an almost unlimited number of direct cable connections can be made, and car designers have the freedom to locate many more controls on the steering wheel where they will be more visible and easily accessible at a fingertip’s distance. The new fixed-hub steering wheel is being introduced in the new C4-model where Citroën has put as many as 21 controls on the steering wheel.