Taking a crack at carbon fiber

As we all know, light and heavy vehicle manufacturers alike are facing the imposition of fuel economy mandates that’s forcing all sorts of changes upon their car and truck products – changes affecting everything from engine displacement, tires, even the very materials used to construct chassis and body components.

One such change involves greater use of carbon fiber material composites – the same stuff used to build aircraft fuselages – to maintain if not increase vehicle body strength whilst significantly reducing weight. That weight reduction translates, of course, into fuel economy improvements (ah ha!), which are oh-so-vital for light- and heavy-duty vehicle manufactures alike due to new federal fuel efficiency mandates that reside just around the figurative corner.

[The video below provides a nice overview of how carbon fiber composites are manufactured and used in the commercial aircraft world. FYI, listen to most unusual way the narrator pronounced the word “aluminum.”]

Now, steel has mainly been the material of choice in the automotive and truck worlds because of its strength and low cost. Yet the weight of steel is why man OEMs started using aluminum, fiberglass, even some plastic components, in the construction of their vehicles.

The reason carbon fiber composites are so attractive is that they weigh about one-fifth as much as steel, but can be comparable or better in terms of stiffness and strength depending on fiber grade and orientation. These composites do not rust or corrode like steel or aluminum, noted researches at the Oak Ridge National Laboratories (ONRL), a division of the U.S. Department of Energy (DOE).

Perhaps most importantly, according to ONRL, carbon fiber composites could reduce vehicle weight by as much as 60%, thus significantly increasing vehicle fuel economy.

The problem, however, is that carbon fiber composites in the past cost at least 20 times as much as steel and also required a slow, energy-consuming process to make fibers, with large ovens and other capital equipment needed to produce them adding significantly to the price tag. Thus ONRL found in past studies automobile and truck makers uninterested in using carbon fiber unless it dropped in price from $8 to around $3 a pound and production could significantly speeded up.

Now, however, that seems to be changing. Many automakers – especially the luxury brands such as Germany’s BMW – are now widening their use of carbon fiber composites, as lower material pricing and faster production times are now possible.

[It’s a rather long video below, but it provides a good overview of how BMW makes and uses carbon fiber in its products.]

Ford Motor Co. is the latest manufacturer takes a crack at using carbon fiber, partnering with Dow Automotive Systems – part of The Dow Chemical Company – to research the use of advanced carbon fiber composites in high-volume vehicles.

The reason is simple: Ford says it needs to cut vehicle weight by some 750 pounds by the end of the decade not only to meet impending fuel economy rules but boost electric vehicle range targets as well.

"Vehicle weight reduction through intelligent design with a focus on materials focus is a priority," said Florian Schattenmann, director of research and development for Dow Automotive Systems. "This partnership with Ford on carbon fiber composites is a logical next step to progress already achieved through the use of lightweight, high-strength polymers and structural bonding technology."

To make the use of carbon fiber feasible in high-volume automotive production, Dow and Ford plan to collaborate on several fronts, focusing on establishing an economical source of automotive-grade carbon fiber and develop component manufacturing methods for high-volume vehicle production applications.

“Reducing weight will benefit the efficiency of every Ford vehicle. However, it's particularly critical to improving the range of plug-in hybrid and battery electric vehicles,” stresses Ford’s Mascarenas.

Of course, other questions still need to be answered where carbon fiber is concerned – especially in terms of how to repair the material when damaged and how much such repairs might cost.

For example, if dents and dings result in requiring fleets to throw out whole body sections, such as hoods, side fairings, etc., that would make the material prohibitively expensive from a vehicle life cycle perspective.

Still, with the need for fuel economy improvements greater than ever, no stone or material is being left unturned or unexamined by OEMs these days.