Hemp used in doors, seat covers from PET bottles – the future of mobility is not only electric, but with components made from recycled and renewable raw materials it will become really sustainable.
The “soybean car” is still legendary… In 1941 no lesser person than Henry Ford presented a car with body panels made of hemp and soy fiber. The vehicle weighed only 900 kilograms – which was considered revolutionary. However, high taxes made hemp cultivation unattractive on an industrial scale. So back then a development was nipped in the bud that now seems to be taking hold again. Today renewable raw materials are used in components such as arm rests, trunk floors and insulation. Fibers from coconut, beets and coffee grounds are serving as fillers. Sheep’s wool is used in seat covers. Mercedes-Benz has used olive coke in its activated charcoal filters. Kenaf, a tropical member of the mallow family, is used in the interior door panels of the VW Golf. Flax is popular at Opel, in particular for cladding on side panels and tailgates.
Car seats made of vegan leather are beginning to appear and are expected to replace real leather. It feels exactly the same, but is a different material. Volkswagen, for instance, is using “AppleSkin” in its ID. family. The vegetable part of this artificial leather consists of organic waste from apple juice production, which also finds it way into decorative inserts and films. More exotic alternatives are available, made from pineapple fiber or fungi. The interior of the electric Polestar 2 is already made entirely from vegan materials. And the same should be true of tires at some stage. Continental is experimenting with obtaining natural rubber from the Russian dandelion, and has brought a bicycle tire onto the market (link to article). Dandelion rubber could cover the demand for rubber, which is growing all over the world, without having to sacrifice more valuable rainforest for the cultivation of rubber trees. Components of the new S-Class made from renewable raw materials have a total weight of 40 kilograms.
Curiously, Four Motors’ “Bioconcept Car” racing car project has not focused primarily on being the first to reach the finish line. The main aim for the developers surrounding hobby-racer Smudo from the band “Die Fantastischen Vier” was technology transfer. To that end, he and his team have forged an unusual alliance with race car builders and material scientists. They set out to realize cars that run on biofuels and are made of organic materials. Seven concept cars have been built since 2003, which can now be seen racing around the Nürburgring. The latest model is a Porsche 718 Cayman GT4 with 425 hp. Its doors, rear wings, fenders, front splitter and hood, trunk lid, diffuser and front mudguards are made of natural fiber composites. They have to stand up to severe conditions, as the demands placed on the car are enormous. It accelerates from zero to 100 km/h in 4.2 seconds, and sustains speeds of 200 km/h or more during 24-hour races. The findings drive forward the industrial application of natural materials.
Alongside natural materials, recycled materials are also considered perfectly normal these days. Ford once used old jeans to make interior door panels and seat covers in the Focus. The Golf 6 will never be forgotten – part of the steel for the engine block came from the steel skeleton of the “Palast der Republik” (the “People’s Palace”) in Berlin, previously the seat of the East German parliament and a symbol of power in the GDR. The building was demolished from 2006 to 2008. The total weight of components in the S-Class made from recycled materials has now risen to 120 kg – more than twice as much as in the predecessor model. Recycled PET bottles have proven their value in the seats and armrests for Renault’s electric Zoe. Plastic bottles are also being used in the headliner fabric of the swift electric Polestar 2. Furthermore, old cork has found its way into the car’s head restraints. Volvo is planning that as of 2025, the synthetics it uses should contain at least 25 percent recycled material. The Volvo XC60, for example, has a tunnel console made of renewable fibers and plastics from discarded fishing nets and maritime ropes.
Well, it’s not beautiful, but the point is what’s inside: the two-seater Luca is made entirely from recycled materials such as aluminum, PET bottles recovered from the sea, UBQ bio-based plastic and flax. It is the latest baby from TU Ecomotive, a team of students at the Eindhoven University of Technology. Luca weighs 360 kilograms and is powered by a 20 hp wheel hub motor. The recycling car reaches a top speed of 90 km/h. At this time there are no plans to go into series production. The students are concentrating first and foremost on highlighting the technical possibilities – which are nowhere near exhausted.
Audi is already working with scientists from the Karlsruhe Institute of Technology (KIT) to develop the next recycling method for plastic components based on petroleum, such as fuel tanks, wheel trim parts, and radiator grilles. This is an important project. After all, the annual need for plastics in cars alone is estimated at around 1.5 million tonnes, of which approx. 230,000 tonnes are recycled. KIT is working on a chemical process for converting waste into pyrolysis oil. The advantage is that its quality matches that of petroleum products and the material can be used to manufacture components of equally high quality. At present, there are a number of promising projects on materials to replace plastics. Daimler is cooperating with the Israeli startup UBQ Materials, which produces bio-based plastic from food and garden waste, diapers, paper and packaging – a product which itself is 100 percent recyclable. The Israelis have found a way to turn this chaotic mixture into a homogeneous mass by breaking down organic waste into its natural component parts.
Recycling also conserves resources during vehicle manufacture. Aluminum is an ideal construction material – it is light, resists corrosion, and is stable. But it takes a huge amount of energy (and money) to produce. BMW therefore channels valuable aluminum waste into a closed loop. Its plant in Landshut processes 500 tonnes of aluminum every day. This equates to 25 times the weight of the Eifel Tower every year. The aluminum is used to manufacture numerous components for gasoline/diesel cars, motorcycles and lightweight components for electric cars. Around half of it is left over from production, which is returned to the established cycle, melted down and used in production again. Audi sends back aluminum waste from its press shops directly to the supplier. It processes the material that Audi then uses to make parts for its cars in the series A3 to A8 and for the electric models e-tron and e-tron Sportback. In all, the procedure saves 150,000 tonnes of CO2 annually.
Everything comes to an end – even the life of a car. Yet life goes on, at least in parts. In Germany, under certain conditions used cars or those damaged in accidents can be returned to a collection point free of charge. Other vehicles that end up here include those that look like new but have production flaws, or developmental vehicles from a manufacturer’s pilot series. The good news is that 95 percent of an end-of-life car can be recycled. That is enshrined in EU law. The passenger cars are taken apart, piece by piece. First of all, specialists remove the fuel, oil from the engine and gearbox, brake fluid, and coolants from the air-conditioning system. Parts that are still intact are taken out and join the market for replacement parts – with a warranty. The materials collected include copper cables, aluminum and iron waste, glass and plastics. Electrical waste contains rare earths. Platinum and rhodium can be recovered from catalytic converters, while old tires can be used to make asphalt. Batteries from electric cars are either remanufactured or begin a second life storing electricity. What is left is fed to the shredder. The car body is ripped apart and metallic materials are sorted and melted down. Some non-metallic residues are re-processed. This whole procedure enables 95 percent of the vehicle to be recycled, so only a small fraction ends up in landfill.
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