Text Size AAA
Aug 1, 2011

Taking Fuel Economy Further


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.”   


Showing 1-10 of 10 comments

August 2, 2011

Thanks for pushing the thinking to the next level regarding advanced composites. Am I correct in assuming you are in communication with the auto makers? The auto makers would do themselves a favor by having your representatives on their development teams.

August 2, 2011

Advanced composite materials for automotive design have already been used by Aptera, which achieved a 1800 lb weight for a two passenger vehicle. The Aptera also reached 200 mpg at 60 mph using batteries only! Any auto maker that claims advanced composites and vastly better mileage cannot be achieved with today's technology is simply not telling the truth!

August 2, 2011

The industry seems to forget, or be blind to what has already been done. I used to own a 1958 BMW Isetta. Seated 2, weighed about 750 pounds, and could manage about 50mpg with ancient design gas engine. Made with steel tubing and body shell. Certainly not an ideal car, but it was done with (now) 50 year old technology. A more modern design, built of aluminum or carbon fibre, and with modern engine/hybrid technology should easily manage 100 mpg at a steady speed. No new engineering breakthroughs needed - just apply what is already known.

August 2, 2011

Here in the UK Vauxhall are bringing out their interesting E-REV vehicle next year called the Ampera which they maintain will equate to 165 mpg. US citizens may want to press for a left-hand drive version when it appears

August 3, 2011

Ron makes a great point; in the mid-70s, I had a 1964 Datsun Fairlady that got 45mpg in town, 50+ on the open road, and always exceeded 35mpg in closed-course roadracing. Of course, it didn't have AC or soundproofing, the "heater" was of almost no value in 20F-30F Oregon Winters, and there were no fancy-schmancy creature comforts the car-buying public insists upon today.

While that Fairlady was a blast to drive AND very economical, it today would have almost no market, primarily because it would not conform to current comfort expectations. As consumers, we need to be REAL honest when asking - what levels of "trim" am I willing to do without, and conversely, willing to pay for? That 9-year-old Fairlady cost me $500. Today, a 9-year-old car is $5,000, $10,000, $25,000. New "energy-efficient" models sell for $25,000-$50,000. When small serviceable economic cars are selling in India for $2900, is "hi-tech" really the answer to our energy perils, or is "hi-tech" more of an excuse?

August 3, 2011

Perhaps it is time to fire American managers and boards, and bring in Chinese and Japanese people to run US heavy industries. The displaced personnel can then move on to doing what indigenous US industrial leaders do so well; like run amazingly innovative and entrepreneurial banks and hedge funds. They really know how to get a lot of mileage out of financial vehicles, even if they are unsafe at any speed.

August 4, 2011


You are indeed correct in assuming that RMI is in touch with automakers. Our forthcoming publication, Reinventing Fire, was peer-reviewed by several automakers and we relied heavily on their direct input during the research phase of writing the book. We are now pursuing consulting projects with them in order to get the ideas of the book on the ground.

August 4, 2011


Thank you for mentioning Aptera. The 2e is a great example of advanced-materials design underpinned by the fundamentals of vehicle fitness.

August 4, 2011

Ron, Neil,

The past models you mention and other models like them have demonstrated that no technological breakthroughs or manufacturing transformations are required to meet the 54.5 mpg standard. From 1975-85, Detroit responded with aplomb to Gerald Ford's CAFE standards, raising rated efficiency 62% while making cars safer, cleaner, and no less powerful, and without a major manufacturing transformation. You also make a good point that fuel efficiency, at least on the scale of current CAFE standards, need not be a high-tech solution or drive additional cost. Models like the G.M. Sonic and Ford Fiesta demonstrate this. Tata's Nano is another example, but would come in at a much higher price point and be much less fuel-efficient after adding safety features to meet standards to which the Fiesta and Sonic are subject.

August 5, 2011

We need to go in two directions. One is to retrofit existing vehicles. For example, regenerative braking with a "bolt on kit" could save massive amounts of energy.
Second is to create a new independent vehicle industry. No use expecting dinosaurs to change their spots. Government (like NASA), or private or mixed, I don't care. Now!
I am convinced this is a time of flux. Existing institutions, and societies, will struggle to survive as we deal with realities of climate change and diminishing resources. Therefore, the time is ripe for innovation on a massive scale.
Actually, we don't really have a choice.

PAGE: 1 
Show Subscribe