Lightweight garage #28 Plastic components @ Bayer K67

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Lightweight garage, News

The vehicle

In 1967, a concept car was presented by BMW and Bayer at the plastics trade fair in Düsseldorf. Equipped with a 120 hp engine from the BMW 1600ti, the car had a kerb weight of just 850 kg thanks to the extensive use of plastics. Thanks in part to this combination, the K67 was able to reach a top speed of 190 km/h: 15 km/h more than the BMW 1600ti.

The vehicle was registered for road use in the same year. However, only two of the five examples built were able to drive on the road, as three were sacrificed in crash tests.

The technology

The idea behind the cooperation between BMW and Bayer was not just to develop a vehicle with a plastic body, as these already existed at the time. The aim was to develop a production-ready car in which other components were also made of plastic.

This goal was achieved: the K67 has a floor assembly with a sandwich construction made of glass fiber reinforced plastic (GRP) and a hard foam core. The fuel tank is made of polyamide and the instrument panel and center console are made of polyurethane.

From a structural-mechanical point of view, the use of a GRP sandwich structure is particularly interesting. The sandwich structures are characterized by good specific mechanical properties, which are achieved by the clear separation of tasks between the cover layers and the core. The rigid and strong cover layers absorb the normal stress from the bending. The core structure between the two cover layers is mainly responsible for increasing the distance between the cover layers, which increases the area moment of inertia and thus the bending stiffness. In addition, the core absorbs the occurring shear load.

The lightweight aspect

The plastic car from Bayer and BMW reached a weight of 850 kg and met the requirements to be approved for road traffic. By reducing the empty mass, among other things, the K67 was able to achieve a speed of around 8.5 % higher than the BMW 1600ti, even though both vehicles had the same engine.

At the 2016 plastics trade fair, Covestro AG presented another concept vehicle (K2016) with a wide use of plastics.

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