YOKOHAMA, Japan -- Nissan aims to slash the weight of redesigned models by 15 percent below comparable 2005 models to cut emissions and meet stricter fuel economy standards.
The goal is to cut the weight in all full model changes after 2015. The three-pronged weight-loss program focuses on using new materials, re-engineering parts and developing better construction methods.
Cutting a car's weight by 15 percent can reduce emissions by up to 6 percent, said Kunio Arishige, Nissan Motor Co.'s general manager for advanced vehicle engineering, at a briefing last week.
"The trend has been for each successive model change to get heavier and heavier," Arishige said. "So reducing weight by this much is a pretty high hurdle."
Automakers increasingly seek to take out pounds because lighter cars deliver better fuel economy from the same engine performance. Mazda Motor Corp. is among those making weight-watching a cornerstone of product planning.
By 2015, Mazda aims to boost average fleet fuel economy by 30 percent above 2005 levels. Its strategy calls for trimming 220 pounds from the next generation of each model. The move is seen as contributing to a 5 percent increase in fuel economy for each car.
While Nissan's electric-vehicle program often captures the spotlight for being zero emissions, Nissan acknowledges that gasoline engines will be the mainstay for years. Nissan already has begun cutting weight to make recently overhauled models greener.
The newly redesigned Infiniti M, for example, shed 33 pounds when engineers increased the use of high-tensile steel. The luxury sedan also lost 3 pounds when they used a spongy foam-core floor undercover instead of a solid synthetic resin one.
Engineers also trimmed 44 pounds from the latest Nissan 370Z by using aluminum instead of steel for the side and back doors, Arishige said.
Other advances come through redesigning parts, often to combine what used to be several components into one or by making them smaller and more lightweight.
In the latest version of Nissan's March small car, engineers were able to take out 4.6 pounds by reducing the thickness of the fuel tank wall by 25 percent.
And the latest X-Trail SUV lost 13 pounds because Nissan slimmed its front side members and re-engineered the suspension to pick up the slack in cushioning front impact.
Nissan also is reconsidering vehicle construction.
It used to be that components had to be extra thick to account for margins of error in forecasting bending and breaking points. But through more accurate computer modeling, engineers often are able to make components smaller and lighter.
Nissan reckons that can slice 20 percent off the weight of some components.