Intelligent solutions for lightweight vehicles

Louise Smyth

Antje Lewe discusses how modern materials benefit automotive design in a variety of ways

Huge weight savings can be achieved with modern passenger compartment materials. Technical plastics are materials for the future for the automotive industry. After all, ever more stringent upper emission limits must be met, and customers have to be offered economical solutions despite rising fuel prices. That is only possible if vehicles become lighter.

The average vehicle weight has already fallen by 20% since 2008 – and Dr Erhard Barho, Head of R&D at surface specialist Benecke-Kaliko is convinced that this trend will continue in order to achieve the optimal fuel efficiency. This is made possible primarily by means of lightweight plastic components. Their use is particularly important in vehicles using electric drives, which are still heavy – every gram of weight saved in these means a longer range and better drive performance. But the initial effect of measures to cut consumption and reduce emissions in internal combustion engines, too – such as exhaust gas recirculation systems, particulate filters and electronic control systems – is to increase the vehicle weight, which then has to be saved elsewhere.

Plastics must also become lighter

Numerous plastic materials can already help if they are used in place of the heavier materials employed hitherto. But Barho is certain of one thing: “To also meet future requirements, it will be necessary to develop ever lighter plastic solutions.“ After all, experts estimate that plastics will constitute up to 18% of the weight of an average vehicle by 2020.

The materials for the vehicle interior offer an especially large potential. This is where Benecke-Kaliko comes in, with its lightweight construction solutions. The ultralight Xpreshn Light and Xpreshn HD Light decorative foils, for instance, offer vehicle manufacturers the ability to reduce the weight of their vehicles without the purchasers having to accept lower quality or even lower comfort as a result.

No adverse impacts on other product properties

Xpreshn Light and Xpreshn HD Light, which is cross-linked for especially high grain stability, are expanded foil laminates with a compact upper foil and a foam lower foil. The foils are deep-drawn in the customer’s plant and bonded to the substrate – for example, the door cladding. “They enable a further 20% weight saving compared with the Xpreshn and Xpreshn HD materials, which were themselves conceived as lightweight design solutions,” says Barho. “This means they are up to 60% lighter than conventional solutions.” However, the advantages extend far beyond the weight saving and the associated environmental benefits: the two materials permit tight radii and impress buyers thanks to their grain stability, surface quality and dimensional stability. They are also available with the “high scratch resistance” option.

Another lightweight construction solution is Benecke-Kaliko’s Acella Light trim and upholstery material for seats, consoles and decorative elements. “The material weighs 20% less than comparable standard surface materials,” explains Barho. “It is free of plasticisers and foaming agents that are toxic to reproduction and also contains no heavy-metal stabilisers.”

The Yorn Light foil solution is used for instrument panels, door trims, consoles, head restraints, seat backs, tray areas and pillars. Benecke-Kaliko claims that this environmentally friendly and inexpensive surface material for vehicle interiors enables weight savings of up to 50% compared with standard decorative materials, and its carbon footprint is up to 46% smaller than standard PVC foils. It can be used wherever PVC expanded foils have been used up till now. The difference is that lighter polypropylene (PP) is now used instead of a PVC foam. The company’s experts have calculated that if lighter foils are used consistently, up to 2kg can be saved per vehicle. Yorn Light’s other convincing properties are that it is soft to the touch and has a wide processing window and a broad spectrum of colours and grain designs. 

Lightweight gearbox adapter for premium cars

Other options for continuing consistently in the lightweight construction vein include vibration control components, which ContiTech manufactures. The latest example is a new gearbox adapter for premium cars. Its special feature is that the component is 55% lighter than the previous aluminium variant thanks to the use of BASF’s Ultramid glass-fibre-reinforced polyamide. “Such an enormous reduction in weight is a huge step in the field of lightweight design,” says Kai Frühauf, who heads up ContiTech’s Vibration Control business unit. The first car in which the gearbox adapter will be fitted was unveiled in January 2016.

This major weight reduction is made possible by optimally exploiting the material’s characteristics. “A wide range of simulation tools was used throughout the development process. The perfect interaction of strength analysis and process simulation with a thorough understanding of the material itself enabled this significant weight reduction to be achieved,” declares Diethard Schneider, head of Advanced Development Lightweight Construction at ContiTech Vibration Control.

Antje Lewe is with ContiTech