While cars have changed a whole lot even in the last ten years, the laws of physics have not, and weight remains the enemy of speed and fuel efficiency. Carbon fiber is a popular material for trimming weight, because of its unique combination of strength and lightness, but it is quite expensive compared to metals. According to Auto Express, BMW is planning on skirting that issue by transforming carbon fiber production waste from the Project i cars into full-carbon fiber wheels, steering wheels, and propeller shafts.
Carbon fiber is about 30 percent lighter than aluminum and 50 percent more so than steel, which made it an ideal material to counter the heavy hybrid components for the BMW i3 and i8. These vehicles use an underlying carbon fiber structure sourced from BMW’s new carbon fiber production network, and the network could shape up to be the gift that keeps on giving. “Carbon fiber is an expensive material to work with, but if you are using production waste then it’s a different cost structure from working up raw carbon fiber,” BMW lightweight construction manager Franz Storkenmaier told Auto Express. “It’s cheap, and that’s how we can position it as a competitor to magnesium.”
While BMW uses the material for certain body panels in its high-performance M vehicles, and the bodies of the i3 and i8 plug-ins, the next step is to build more critical components out of carbon fiber. Storkenmaier says that BMW is working on a carbon fiber and alloy “hybrid” wheel with a carbon rim and alloy spokes. This combination alone would be 25 percent lighter than forged alloy wheels, while a fully carbon wheel would add another 10 percent in weight savings. A carbon fiber steering wheel is also possible, which would build even further upon the carbon fiber-trimmed steering wheels of today (these still use metal frame underneath).The technology is no pipe dream, but it is still a few years down the line seeing as it needs to pass European Union inspection and regulation before it can go into series-production cars.
BMW also developed a carbon-plastic material (Secondary carbon-fiber-reinforced-plastic) which could be used for future applications like dashboard support structures and seat frames. These parts are typically made of heavier metals, so replacing them with lightweight CFRP materials could play a big role in BMW’s plan to reduce its vehicles' weight.
There isn’t any word yet on exactly when these lightweight carbon fiber parts could reach production, but the news reflects well on BMW’s investment in Project i. All of the Project I naysayers, who thought that BMW had lost its way by expanding into the uncharted territory of advanced hybrid electric technologies, might eat their words when they benefit from the improved performance and efficiency of future BMW vehicles.