TRAVERSE CITY, Mich. -- Lightweight vehicle materials are delivering significant side benefits to automakers striving to improve fuel economy.
Toyota, for example, has found that its pursuit of lighter bodies through high-strength steel has resulted in production lines that are less expensive to build, said Takefumi Shiga, general manager of Toyota Motor Corp.’s No. 1 Body Division in Japan.
The side benefits will take some of the sting out of adopting costlier lightweight materials, such as aluminum, high-strength steel and carbon fiber.
Toyota is also finding that using carbon fiber parts allows it to mix materials on the same welding lines, instead of operating separate welding lines, Shiga told an audience Monday at the 2014 Management Briefing Seminars.
The improvement to lighter materials also enables Toyota to use advanced laser-screw welding to bond them. Shiga said that laser-screw welds can be applied at the rate of a half-second per spot, compared with two to three seconds for a traditional weld. Laser-screw welding makes pinpoint welds.
BMW, which has embraced carbon fiber for significant parts of its new i3 electric car, has picked up a benefit in collision repair, said Franz Storkenmaier, BMW’s head of lightweight construction and vehicle weight.
Damaged portions of the carbon fiber body can be cut away for repair, and new sections of carbon fiber can be bonded back in their place.
The i3 uses numerous carbon fiber parts, including its frame, bumper, rear seat buckets, propeller shaft and multiple chassis and engine compartment parts.
Storkenmaier said the breakthrough of i3 construction opens the door to other BMW vehicles designed and built the same way.
Additionally, the innovations in i3 body construction have enabled BMW to operate a paint line at its assembly plant in Leipzig, Germany, that requires half the energy of a traditional steel-body paint line and consumes 70 percent less water.
“It’s a different construction,” Storkenmaier said of working with carbon fiber. “It’s a quantum leap in material design.”