Fuel Economy: Why Not Take It Even Higher?

Last week, President Obama announced a plan to boost the fuel economy of vehicles sold in the U.S. from 27.5 to 54.5 mpg beginning in 2017—effectively doubling fuel economy standards by 2025.

This important step—agreed upon by the auto industry after some wrangling—to reducing America’s reliance on foreign oil requires annual fuel-economy increases of 5 percent for cars. Light trucks, such as pickups will be able to raise fuel-economy at 3.5 percent for the first five years the rule is in effect—then at a rate of 5 percent thereafter as reported by Bloomberg Businessweek.

“This program will result in significant cost savings for consumers at the pump, dramatically reduce oil consumption, cut pollution and create jobs,” the administration said in an official statement.

Recent studies show that automakers could reach the 54.5 mpg threshold with just tweaks to existing car design. And, while these incremental improvements are a step in the right direction toward mitigating the economic and environmental impacts of oil use, RMI experts suggest that the time is right for automakers to seize an opportunity to reestablish themselves as global leaders in innovation, manufacturing and performance.

Reinventing Fire, slated for publication this fall, offers a comprehensive vision for weaning the transportation sector off fossil fuels. One key enabler of the transition is to apply integrative design, vehicle fitness and new manufacturing methods, which can save far more fuel at a similar sticker price by simplifying automaking and shrinking powertrains.

“We are currently on the tail end of a 100-year learning curve, where we see design improvements flattening out,” said Greg Rucks, RMI transportation consultant. “Instead of wringing the last bit of innovation left in current designs, the same amount of innovation and design effort could be more productively applied toward revolutionary autos that exceed 100 mpg with better safety and performance. Automakers who recognize this early will be in the best position to capture market share.”

Out-Innovating the Competition

Some smart automakers have already achieved efficiency improvements by making their cars lighter. Audi, for example reduced the weight of their TT-RS 35 percent over a standard steel frame by using aluminum steel hybrid technology. But even this effort falls short, achieving an mpg rating of just 35.6.

Meeting the 54.5 mpg standard with existing (or incrementally improved) technologies will require design innovation to shed additional pounds.

“There is only so much lightweighting we can achieve with conventional materials,” Rucks said. “If automakers are putting in the effort to achieve 35 percent weight savings in a current platform, we have the opportunity to open up a completely new design space.”

The key to taking significant amount of weight out of a vehicle without making it smaller is to substitute lighter, yet stronger materials such as advanced composites like carbon fiber. Transitioning to advanced composites—as compared to design optimized for metals—could vault automakers into the realm of 150 + mpg, and capture safety and performance benefits (at only one-third the density of steel, carbon fiber is able to absorb up to six times more crash energy than aluminum).

“The difference between achieving 54.5 mpg vs. 100+ mpg is the difference between meeting a mandate versus out-innovating your competitors and transforming the market,” Rucks said. “A fuel savings gap that significant would make efficiency a far greater factor in consumer buying behavior.”

Getting to Revolutionary Vehicles

For automakers, a shift to advanced materials requires significant retooling both in the boardroom and on the factory floor.

“While clean-sheet integrative design yields the largest benefits, we can’t assume that Detroit can tackle plants, people, products and processes all at once,” Rucks said. “However, taking the right steps in the right order can mitigate risk and maximize competitive advantage.”

For example, in its M3 sedan, BMW introduced a carbon fiber roof as an option. Adding this feature required hiring the right people to understand the processes, and buy new tooling for that specific part. “Offering advanced versions as an alternative option to current models carries the added benefit of gauging how much efficiency and the performance benefits of carbon fiber are worth to the consumer,” Rucks said.

As automakers move further down the learning curve and continue to pursue vehicle fitness, introducing smaller fleets allows companies to test the market.

“Right now, the U.S. is far behind German or Japanese automakers in the use of advanced composites,” Rucks said. “Reaching a 54.5 mpg standard will put a big dent in our oil consumption, but revolutionary lightweight cars can reposition the U.S. auto industry as a world leader.”

Kelly Vaughn is public relations specialist for Rocky Mountain Institute.