Lightweight door panels incorporate natural fiber

The German subsidiary of Johnson Controls in Burscheid is supplying a series of innovative door panels, seat structures and instrument clusters for the new BMW 3 Series.


Johnson Controls makes the hybrid door panels for the new BMW 3 Series using a combination of natural fibers and plastic.

The non-visible door panel elements employ a combination of wood fibers and polypropylene (PP) that are 20% lighter than conventional components. The natural-fiber carrier is directly molded with the plastic matrix.

A state-of-the-art process known as groove lamination is used to apply the fabric or leather trim onto the door panel. This process involves the trim being joined in recesses, eliminating the need for an additional component and further reducing weight.

Four special features characterize the seat structure of the new BMW 3 Series. The use of high-strength steel means it is both stable and lightweight. The low seat back pivot point makes the seat particularly comfortable as it snugly fits the occupant's back. The structure also offers a very finely graduated recliner to ensure the best sitting position. Finally, adjusting motors using four-pole technology, in some cases with rare-earth magnets that have a stronger magnetic field than conventional ferrite magnets, are used in the electrically adjustable seats. This means they need a smaller installation space and are approximately 200g lighter. With up to four motors per seat, this also enables a significant weight reduction. The seat structures are modular in design and in the case of the driver's seat, a weight reduction of three to four kilograms is possible depending on the model.

The basic instrument cluster for the new BMW 3 Series has day and night design and not only offers high-quality analog displays and LED pilot lights but also a 2.7-inch TFT display. The instrument cluster features a bidirectional Automotive Pixel Link (APIX) high-speed point-to-point connection that facilitates robust image and control data transmission using just one interface. This technology is used in displays and stepper motors on the design circuit board to communicate with the electronics on the PCB (printed circuit board) behind it.—[email protected]

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