DEARBORN, Mich. — Roofs made of carbon fiber. Plastic windshields. Bumpers of aluminum foam.
What sounds like a science experiment could be your next car.
While hybrids and electrics may grab the headlines, the real frontier in fuel economy is the switch to lighter materials.
Automakers have been experimenting with lightweighting, as the practice is known, but the effort is gaining urgency with tougher gas mileage standards. To meet the government’s goal of nearly doubling average fuel economy to 45 mpg by 2025, cars need to lose some serious pounds.
Lighter doesn’t mean less safe. Cars with new materials are already acing government crash tests. Around 30 percent of new vehicles already have hoods made of aluminum, which can absorb the same amount of impact as steel.
Ford gave a glimpse of the future last week with a lightweight Fusion car. The prototype is about 800 pounds lighter than a typical Fusion.
The instrument panel consists of a carbon fiber and nylon composite instead of steel. The rear window is made from tough but thin plastic.
The car has aluminum brake rotors that are 39 percent lighter than cast iron ones and carbon fiber wheels that weigh 42 percent less than aluminum ones.
Because it’s lighter, the prototype can use the same small engine as Ford’s subcompact Fiesta, which gets an estimated 45 mpg on the highway.
The car won’t be in dealerships anytime soon. For one thing, it’s prohibitively expensive. Its seats, for example, cost up to $73 apiece because they have carbon fiber frames. The same seats with steel frames are $12.
Still, prototypes are helping Ford and other companies figure out the ideal mix of materials.
“These are the technologies that will creep into vehicles in the next three to five years,” said Matt Zaluzec, Ford’s technical leader for materials and manufacturing research.
Some vehicles have already made a lightweight leap. Land Rover’s 2013 Range Rover, which went on sale last year, dropped around 700 pounds with its all-aluminum body, while the new Acura MDX shed 275 pounds with use of high-strength steel, aluminum and magnesium.
cars lighten up
Here’s a look at some of the materials automakers will use to shed the pounds:
•HIGH-STRENGTH STEEL: Steel isn’t going away. Chances are, high-strength steel — a lighter and stronger steel mixed with other elements such as nickel and titanium — already makes up at least 15 percent of your car’s weight. Some newer models, such as the Cadillac ATS, are nearly 40 percent high-strength steel.
High-strength steel costs about 15 percent more than regular steel, but less than other materials such as aluminum. It still weighs more than aluminum, but continuing advances could cut that weight. Extremely thin but strong steels made with nanotechnology could be on cars by 2017.
•ALUMINUM: The typical vehicle already contains around 340 pounds of aluminum, or about 10 percent of the weight of a midsize car. It’s most commonly used in engines, wheels, hoods and trunk lids.
Aluminum is lighter than steel and easy to form into a variety of parts. It’s also more corrosion-resistant than steel.
There are drawbacks. The supply of steel is many times greater than that of aluminum, and will be for many years. Aluminum also costs 30 percent more than conventional steel, and an increase in demand could make aluminum prices volatile.
Still, consultant McKinsey and Co. predicts aluminum’s use in the auto industry will triple by 2030.
•CARBON FIBER: Airplanes use it. Boats use it.
Carbon fiber is a high-strength material made from woven fibers. It’s half the weight of steel, it is resistant to dents and corrosion, and it offers the most design flexibility, since it can be shaped in ways that stamped metal can’t.
But the high cost of carbon fiber and the time it takes to form it into parts are huge barriers for the auto industry.