By Neal E. Boudette and Mike Ramsey
DETROIT—Auto makers wrestling with ambitious mileage goals have touted hybrids and electrics as the wave of the future, but they have found a quicker path to improved fuel efficiency, reinventing the way traditional gas-powered cars are built.
For the past century, autos were made largely of steel. But pressed to produce cars and trucks that go farther on a gallon of gas, manufacturers gathering here this week for the Motor City’s annual auto show are cutting weight by substituting more plastics, aluminum and magnesium, including materials once found only in high-end race cars.
Only a handful of parts fashioned from new, lightweight materials are in current models—for example, the magnesium tailgate of the Explorer, the sport utility vehicle from Ford Motor Co. But in four to six years, car companies will roll out vehicles completely redesigned to use a wide mix of specialized materials.
Ford is testing a prototype F-150 pickup truck—aimed for launch by 2015—that features aluminum instead of steel body panels. It will weigh 700 pounds less than the current model, the company said, a reduction of about 15%.
Other lighter-weight vehicles will be unveiled this week at the North American International Auto Show here. The new Chevrolet Corvette that made its debut Sunday features an underbody made of aluminum, and a hood and roof made of carbon-fiber composite, the same material used in Formula One race cars. BMW AG will display an electric car with a frame made of the same composite. The new Lincoln MKZ sedan will showcase an aluminum roof frame.
“Vehicles are going to look very different in a dozen years,” Robert Bienenfeld, senior U.S. manager for energy strategy at Honda Motor Co., said at a recent symposium on fuel-economy. “We are going to redefine what a conventional vehicle is.”
The federal government is requiring auto makers produce vehicle fleets that average 54.5 miles per gallon by 2025, roughly double today’s standard. Europe has set limits on carbon-dioxide emissions that, in effect, impose similar fuel-economy targets.
Shaving weight is one strategy auto makers will use to reach those goals. Ducker Worldwide, a market researcher based in Troy, Mich., predicts the average vehicle will shed 400 pounds by the 2025 deadline through a doubling of aluminum. Steel, which now accounts for 56% of average vehicle weight, is expect to fall to 46%, according to the research group.
The U.S. Council for Automotive Research, a collaboration of General Motors, Ford and Chrysler Group LLC, estimated about 350 pounds of magnesium will be used in the average vehicle by 2020, replacing 500 pounds of steel.
Read more in The Wall Street Journal.