The least expensive way to improve fuel economy is to reduce vehicle weight, and reduce it everywhere, so automakers are open to new ideas and new materials.

“You go to the [automakers’] engineering offices and they want to take weight out of everything -- like cupholders,” said Phil Sklad, field technical manager-lightweight materials program with the U.S. Department of Energy.

EPA’s new rules, formally announced Sept. 15, would begin to be phased in during 2012, and surpass earlier Congressional requirements for 35 miles per gallon by 2020. The government is starting a required discussion period for the regulations now with the expectation that they will become official later this year.

Sklad joined automakers and auto industry watchers to discuss lightweighting during the Society of Plastics Engineers’ Automotive Composites Conference & Exhibition Sept. 15 in Troy. While the Corporate Average Fuel Economy requirements are cited in discussions about a growing market for hybrids and plug-in electric vehicles, consumers are still going to want a range of vehicles -- both large and small, said Mike Jackson, director of North American vehicle forecasts for consulting group CSM Worldwide.

“There’s still going to be a place for an F-150 [pickup truck],” said Jim deVries, staff technical specialist and manager-manufacturing research department for Ford Motor Co.’s research laboratory. “We know what we can do for fuel economy with small cars, but the different issue will be with trucks.”

The new rules do not separate out cars and trucks, unlike current regulations which call for 27.5 miles per gallon performance from cars and 22.5 miles per gallon from trucks. Instead there will be one unified requirement.

Dearborn, Mich.-based Ford and other automakers will still make what consumers will buy, deVries said, and will need ways to supply those vehicles without sacrificing performance or adding too much cost. Carmakers will be looking at material and powertrain improvements simultaneously to meet those goals.

That call to lighten up will not automatically give a nod to traditional composites, however.

“Five to six years ago, composites like [sheet molding compound] competed against steel in terms of weight save and cost,” deVries said. “Steel is no longer the standard we’re up against. Now it’s other lightweight materials like aluminum and magnesium.”

Steel will still play a part, Sklad said, but carbon fiber is the plastics option getting the most attention now because it offers the biggest potential weight savings. It is also among the most expensive options both for raw material costs and processing.

General Motors Corp. of Detroit uses carbon fiber on its Corvette ZR1 model, but at $106,000, it is easier to afford the material, said Tadge Juechter, chief engineer for the Corvette and the Cadillac XLR sports car.

“Lightweighting has to be affordable,” Juechter said. “You need to make the material at a low cost point.”

Much of the focus on driving down the cost of carbon fiber will be in finding more efficient ways to process it, he noted.

The automakers also urged suppliers to look beyond body panels for potential markets for composites. Structural components can make an even bigger impact if it can replace steel, deVries noted.

Composites using lighter weight natural composites instead of glass also are an option increasingly gaining interest, Sklad said.