Mazda seeks to lighten redesigned vehicles

Mazda Motor Corporation in the US has a goal that will at some point become impossible to achieve: eliminate at least 220 pounds of weight every time it redesigns one of its models.

But automakers argue they have to pursue such ambitious targets as they work to meet stricter government fuel-economy standards.

Meanwhile, engineers working to take weight out are constantly battling safety and emissions regulations and consumer demand for more comfort and convenience features, all of which add weight.

Early on, cutting out weight is not too tough a task. Mazda, as part of an approach it calls SkyActiv, made its CX-5 crossover as much as 575 pounds lighter than its similar-sized predecessor, the CX-7.

“Obviously that’s going to get harder and harder,” Dave Coleman, vehicle development engineer for Mazda’s North American operations, told Automotive News after speaking to the Center for Automotive Research’s Management briefing seminars. “We focused so much on the low-hanging fruit that we still have a lot of room.”

To make such a difference, Mazda made big changes, such as designing the frame in a way that less steel is needed to provide the necessary strength, as well as some minute alterations that have a big cumulative effect. For example, the CX-5 uses bolts that are 8 grammes lighter.

Other carmakers, including Audi, have increased their use of lighter materials, including aluminum, magnesium and carbon fibre. The Wall Street Journal recently reported that Ford is considering a largely aluminum body for the next generation of its F-150 pickup truck.

Manfred Sindel, quality manager for Audi, said lighter vehicles have many benefits beyond fuel economy, including better performance and handling.

But more exotic materials cost more, and in some cases too much to be practical today or indeed anytime soon.
James Morgan, Ford’s director of global body exterior and stamping business unit engineering, said some on his team say carbon fibre is “the material of the future – and always will be.”

Coleman said Mazda will need to employ more advanced materials in future generations of SkyActiv models. He said their cost will inevitably come down as they become more widely used throughout the industry.

But he admitted that weight reduction can only go so far: “Or eventually, they’ll not weigh anything.”

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