The overall performance and fuel economy of any vehicle is determined by the complex interaction of engine power, aerodynamics, weight, and drag, among other things, and automakers are continually looking for ways to tweak these.
When it comes to weight, however, there are special considerations. Typically, weight and safety are at odds, heavier vehicles being safer than light vehicles, simply by virtue of the fact that less weight typically means less metal protecting the driver. The only problem is that, the more weight you add, the worse your fuel economy and performance. Then, to recover performance, you have to add a larger engine, which further impacts fuel economy.
On the other hand, the performance / fuel economy spiral works both ways, and lighter materials don’t necessarily result in an unsafe vehicle. Volvo, for example, has been experimenting with structural supercapacitor panels, which could replace non-essential body panels, eliminating the heavy sealed lead acid battery. It’s a small step, but a lighter battery means slightly less engine power required to move it. The engine gets smaller, uses less fuel, and emissions are reduced.
All automakers are working to improve fuel economy and emissions without impacting performance. The Volkswagen XL1, uses an F1-derived carbon-fiber monocoque, is rated at 261 mpg, and weighs a scant 1,900 pounds. One of VW’s brands, Audi, has just introduced other lightweight innovation, perhaps in an area you wouldn’t expect. Audi’s new springs are 40% lighter than the steel versions they replace, and they’re made of glass fiber-reinforced plastic (GFRP). Spread out over the four corners of the suspension, GFRP springs save nearly 40 lb over the weight of the original vehicle.
Interestingly, GFRP springs, besides being lighter for better fuel economy, also enhance performance, less weight when cornering, accelerating, and braking, better all around!
Image © Audi