The BMW iFE.20 Formula E racer uses a cooling shaft manufactured from flax fibers—the first BMW race car fielded by a works team with parts made out of renewable textile fibers.
Compared with carbon, flax has greater absorption and greater impact resistance, which can be advantageous on the street circuits with their bumps and crash barriers, on which Formula E takes place, BMW said. The same is true of contact with other cars during races, it added.
The flax cooling shaft that we use in the BMW iFE.20 is further proof of the hugely important role of BMW i Motorsport as a tech lab for the BMW Group. We are consistently using Formula E as an innovative platform for series development—in this instance for testing flax in extreme weather conditions. What’s particularly remarkable is the fact that in some areas this renewable material even has advantages over materials established in racing, such as carbon. Our ambition is to always use the best suited material for each part.—BMW Group Motorsport Director Jens Marquardt
Like its predecessor, the BMW iFE.20 has a uniform chassis as stipulated by Formula E regulations. However, there are areas in which BMW i Motorsport engineers were able to improve the car with the aid of insights gained from Season 5. These primarily relate to the rear structure, which was modified significantly due to innovative lightweight construction.
The development of parts using generative design methods or 3D printing technology saved a considerable amount of weight compared with conventional development and production procedures, and gave engineers more room to maneuver in terms of the center of gravity of the car and weight distribution.
For the first time, parts made of fiber-reinforced plastics made from sustainable raw materials, are being used in a race car competing on a works basis for BMW—in this case, the flax cooling shaft.
The cooling system for Formula E racers feeds the air that rushes into the car’s side pods to coolant-filled radiators connected via a system of pipework to the powertrain’s main heat producing components: motor, power electronics and battery.
It its Gen 2 iFE.20 racer, BMW uses glycol as the coolant and improved the overall cooling system through a number of efforts, including CFD optimization to reduce pressure loss, and the use of materials with high thermal conductivity (e.g. ceramic, casting compound). The flax cooling shaft directs the air to the radiator.
The BMW iFE.20 is the first works BMW racing car in which the material is used. However, the expansion of this concept to include other BMW Motorsport race cars is currently already in the development phase.