Application Center for Wood Fiber Research HOFZET®

Research project

Bioconcept-Car: Sustainable lightweight bodywork as a building block for climate-neutral mobility

Together with HOBUM Oleochemicals, Porsche Motorsport and the Four Motors racing team, we are developing lightweight components made from natural fiber-reinforced plastics for vehicle bodies. They are a sustainable, cost-neutral alternative to conventional body materials and offer technical advantages. We initially test their performance in motorsports under extreme conditions. With the obtained knowledge, we conceptualize a potential material solution for series-production utilization in road traffic. We are thereby supporting the European Union's aim of becoming climate-neutral by 2050.

Lightweight high-performance composites have long been used in motorsports. In view of climate change, efficient lightweight construction solutions are also playing an increasingly important role in everyday vehicles. These reduce the total weight and therefore contribute towards saving energy and reducing emissions. To date, lightweight construction using polymer materials has primarily utilized carbon fiber-reinforced plastics (CFRP). Carbon fibers offer very good stiffness and strength, but their production requires fossil resources and a large amount of energy. Technical challenges exist concerning handling, repair and recycling.

Single, white-painted car door stands in front of a wall.
© Fraunhofer WKI | Federico Böhm
Door of the “Bioconcept-Car”, made from natural fiber-reinforced plastic (NFRP).

Bio bodywork components bring benefits for society and the automotive industry

In this project, we are developing lightweight body components made from natural fiber-reinforced plastic (NFRP) and bio-based epoxy resin. The decorative paint is also to be bio-based. Our goal is to achieve a biogenic content of at least 85 percent in the entire component. This will not only improve the ecological balance: The use of renewable raw materials is also interesting from an economic point of view, as natural fibers cost less than carbon fibers. In comparison, natural fibers do indeed exhibit lower stiffness and strength; these values are, however, sufficient for many applications. Due to their naturally grown structure, natural fibers actually dampen sound and vibrations even better. In addition, they do not cause skin irritation during processing. Their lesser tendency to splinter can also help reduce the risk of injury in the event of accidents. As a result of its chemical structure, the bio-based epoxy resin can be expected to be tough and elastic. This could also be advantageous in accidents.

Porsche racing car with open passenger door in the pit-stop area of the Nürburgring.
© Christoph Habermann
The “Bioconcept-Car” racing car, equipped with bio body parts, during testing at the Nürburgring.

Racing car “Bioconcept-Car” as test vehicle and demonstration object

The Bioconcept-Car of the Four Motors racing team is a rolling test laboratory for environmentally friendly vehicle technologies: biofuels, bio-lightweight components and re-refined oil. In racing use, their suitability for series production is tested under extreme conditions. The development of the bio-lightweight components is funded by the German Federal Ministry of Food and Agriculture via the project management agency Fachagentur Nachwachsende Rohstoffe e. V. (FNR). On its project website, the FNR provides information on the Bioconcept-Car as well as videos illustrating the research work of the Fraunhofer WKI.

To the FNR project website (German)

Development work of the Fraunhofer WKI

Bio-based resins for serial processing of fiber-reinforced components; Subproject 1: Material development and process adaptation 

  • Test vehicle (Bioconcept-Car): Porsche Cayman GT 4 Clubsport
  • Development achievements (planned):
    • Development, characterization and evaluation of bio-based resin-hardener mixtures with regard to an economic implementation in the RTM process
    • Transfer and “proof of concept” of the new developments to the production tool for the door from the previous project
    • Testing and evaluation of the door in the laboratory and in racing use
    • Ecological evaluation of material and manufacturing process compared to the use of petro-based plastics
    • Evaluation of the RTM process under energetic aspects as well as achievable surface qualities
    • Development and testing of a bio-based PU system for the decorative coating
    • Utilization of the low splintering behavior of natural fibers to create a ductile natural fiber-reinforced plastic
    • Consolidation of all results to create a new design of a body component and its evaluation under selected aspects of its utilization in road traffic
  • Objectives:
    • Series production-ready implementation of a series door for the Porsche Cayman GT 4 Clubsport 982 with a biogenic content of at least 85 percent
    • Comprehensive data basis and conceptual design of a component, which should enable automobile manufacturers to consider natural fiber-reinforced plastics in their design process under criteria for road-use approval

Project partners

  • HOBUM Oleochemicals GmbH
  • Porsche AG
  • Four Motors GmbH

Funding

Funding body: German Federal Ministry of Food and Agriculture (BMEL)

Project management: Fachagentur Nachwachsende Rohstoffe e. V. (Agency for Renewable Resources, FNR)

FNR funding reference: 2220NR094A

Project duration: 1.10.2020 to 30.09.2020

 

Funded by the Federal Ministry of Food and Agriculture by decision of the German Parliament

Sustainable biohybrid lightweight construction for future-oriented mobility

  • Project title: “Sustainable biohybrid lightweight construction for future-oriented mobility”
  • Test vehicle (Bioconcept-Car): Porsche Cayman GT 4 Clubsport
  • Development achievements:
    • Production of natural fiber-reinforced plastics and subsequent characterization and testing under standardized and real conditions
    • Feasibility study and empirical data collection
    • Identification and redesign of suitable body components
    • Production of various laminate structures and comparison with regard to, amongst other aspects, the mechanical properties, splintering behavior, fire behavior, economic indicators
    • Testing of the components in the laboratory and on the racetrack
    • Conceptual design and implementation of a small series of the door by means of resin transfer molding (RTM) and of the rear wing by means of the prepreg autoclave process through the project partner Porsche
  • Result: At the beginning of 2019, the Porsche Cayman GT 4 Clubsport 982 was presented to the public as the world's first series-produced racing car with natural-fiber body components.
Single, white-painted car door stands in front of a wall. The top image shows the outside of the door, the bottom image shows the inside of the door.
© Fraunhofer WKI | Federico Böhm
Door of the “Bioconcept-Car”, made from natural fiber-reinforced plastic (NFRP).
The left image shows a flat test specimen made from carbon fiber-reinforced plastic (approx. 1 mm thick, 6 cm long and wide) with visible fabric structure and a hole in the center; at the edges of the hole, the material stands erect. The right image shows a flat test specimen made from natural fiber-reinforced plastic (approx. 1 mm thick, 6 cm long and wide) with visible tissue structure and a hole in the center; at the edges of the hole, the material stands erect.
© Fraunhofer WKI | Ole Hansen
Ball penetration in test specimen (left: CFRP, right: NFRP).
The left microscope image shows 16 black, elongated, thin pieces with a spear-like shape and an approximate length of 3 mm to 12 mm. The right microscope image shows three light-brown pieces with fibrous structure and an approximate length of 1 mm.
© Fraunhofer WKI | Ole Hansen
Splinters following ball penetration (left image: CFRP, right image: NFRP).

Project partners

  • Porsche AG
  • Four Motors GmbH

Funding

Funding body: German Federal Ministry of Food and Agriculture (BMEL)

Project management: Fachagentur Nachwachsende Rohstoffe e. V. (Agency for Renewable Resources, FNR)

FNR funding reference: 22007717

Project duration: 15.6.2017 to 14.6.2020

 

Funded by the Federal Ministry of Food and Agriculture by decision of the German Parliament

Project initiation

  • Pilot vehicle (Bioconcept-Car): VW Scirocco 2.0L TDI
  • Development achievement: Provision of a trunk cover