Responding to federal CAFE (Corporate Average Fuel Economy) standards requiring their vehicle lines to average 54.5 mpg by 2025, automakers have gone all-out offering hybrid, electric, natural gas, clean diesel and fuel-cell vehicles. They’ve maximized gasoline engines with strategies like turbocharging, start-stop engines and regenerative braking. Higher gasoline prices and concern about greenhouse gas emissions and climate change also are creating market pressure for efficiency without sacrificing power.
Trimming weight is another way to increase efficiency. Lighter vehicles use less fuel. And manufacturers are looking to aluminum, carbon fiber reinforced plastics and other materials to “lightweight.” Steel, the industry standard, is undergoing some changes to make it lighter and stronger, as well.
Ford’s announcement in January that it would build F-150 trucks – America’s most popular vehicles – out of aluminum instead of steel was “a game changer,” says Kevin Shaughnessy, general manager for Denver’s Phil Long Ford. Trimmed by more than 700 pounds, “F-150s will have greater fuel economy. With lighter weight the brakes will last longer and it will mean less wear and tear on the components.”
Some high-end cars have been using aluminum, but this is a first for a mass-market vehicle. Shaughnessy says consumers seem less skeptical than might be expected, something he attributes to their understanding how well Ford trucks’ EcoBoost six-cylinder engine worked out in the F-150’s last big change.
To balance aluminum’s higher cost, Ford totally redesigned the truck, reducing the labor needed to repair it. Parts once made in one piece now are segmented and each segment is replaceable. “Ford also consulted the insurance industry on the design to lessen the cost of repairs,” Shaughnessy says. “Ford has put this through unbelievably rigorous testing.”
One potential worry is collision repair. Aluminum repairs must be isolated from steel body repairs, and technicians require training in aluminum bodywork. Shaughnessy says the sheer volume of F-150s will pressure collision repair centers to acquire the space, equipment and training needed to repair them and to earn Ford certification necessary to purchase replacement parts. “Aluminum is definitely the direction the industry is going and Ford opted to be the leader,” he says.
While Ford has gone big on aluminum, BMW’s adoption of carbon fiber reinforced plastic (CFRP) is just as revolutionary. CFRP has been used for several years in racecars and BMW has used it for some body parts on high-performance vehicles. Now BMW is taking CFRP mainstream with carbon fiber passenger compartments (Life Modules) on its new i3 electric and i8 plug-in vehicles.
Carbon fiber is lighter, stronger and more easily shaped than steel. Instead of welds or rivets, carbon fiber uses super-strong adhesives. Its repair also takes specialized training and facilities. “It’s unique because you can cut out a piece of carbon fiber and replace it. You don’t have to replace a whole panel if there’s a crack or tear or break,” according to Schomp BMW’s Business Development Director Michael Dunlap. BMW’s CFRP vehicles can only be repaired in BMW-certified facilities.
BMW is so committed to CFRP that it built a hydroelectric manufacturing plant in Washington State, whose size it’s already expanding. BMW and other manufacturers are researching how carbon fiber can be used in other automotive components, such as springs and brakes, as well.
Both aluminum and CFRP vehicles cost more to produce and have higher initial prices but manufacturers and the government hope customers will understand that they will recoup more than their initial investment with lower long-term fuel costs.
Meanwhile, don’t count steel out. New alloys and manufacturing methods have made it lighter, stronger and easier to fabricate. Since steel’s raw materials are cheaper and more abundant than aluminum or carbon fiber, it will continue to be a contender. And while none of these materials may come out the victor, ultimately consumers will win with stronger, safer and more fuel-efficient vehicles.