Study: Aluminum Superior to High-Strength Steel in Shedding Vehicle Body Mass, Boosting Fuel Economy

A new study shows that an all-aluminum vehicle can shed more than 40 percent body mass, boosting fuel economy by 18 percent when combined with secondary mass savings and other design changes.

The study helps explain why car and truck makers are shifting away from steel to aluminum, and supports projections that aluminum-intensive vehicles will become more common in the marketplace with continued demand for more fuel efficient vehicles.

The research, conducted by EDAG Group and commissioned by the Aluminum in Transportation Group of the U.S. Aluminum Association, was presented last month at the Society of Automotive Engineers (SAE) World Congress during a panel discussion on advances in lower weight materials. I

It comes at a time when automotive aluminum use is at an all-time high, with automakers announcing plans to incorporate more of the metal into vehicle designs – doubling aluminum’s 2008 share of the automotive metals mix by 2025.

“Automakers are putting cars and trucks on a major diet to get better gas mileage, and are saying they’re reaching the limits of using advanced steels to lose weight,” said Randall Scheps, chairman of The Aluminum Association’s Transportation Group (ATG) and automotive marketing director for Alcoa, Inc. “This study reinforces that aluminum is the material of choice to reduce body mass and boost fuel economy – which consumers list as their primary concern when buying a new car or truck –while providing the safety, performance and durability that consumers also demand.”

The study built upon research EDAG performed last year for the Environmental Protection Agency (EPA) examining mass reduction, safety and cost variables in a mid-size crossover Toyota Venza.

The EPA study aimed to reduce vehicle mass by 20 percent while meeting all NHTSA and IIHS safety standards, and maintaining or improving performance, handling and braking.

It found that using a maximized high-strength steel (HSS) Venza body resulted in a body mass reduction of only 14 percent over the baseline production vehicle body, and that the study’s total vehicle mass reduction target could not be met without the use of aluminum closures and chassis components.

The new EDAG research uses a full aluminum body and closures to achieve almost three times the body mass reduction over the EPA study’s HSS vehicle, while still conforming to the same stringent safety and performance standards.

This was done at a modest cost increase – about a dollar per kilogram of weight saved – which, the study said, consumers will recoup in fuel savings in less than two years of operating the more efficient vehicle.

Aluminum intensive vehicles – like Audi’s A6, the Tesla Model S, and Land Rover’s Range Rover are already on the road today, with more expected to be in showrooms in the next few years.