Fuel economy in the automotive industry has been largely dependent on aerodynamics and powertrain enhancements, but lightweight cars are going to take us into the future.
Since CAFE (Corporate Average Fuel Economy) standards were first implemented by the EPA (Environmental Protection Agency), back in 1978, the main means of reducing fuel consumption and emissions has been via engine and transmission development, as well as aerodynamic enhancements, which explains how the Chevy Camaro, an American muscle car, between 1977 and 1986, was available with an engine as small as 88 hp.
Of course, we’ve come a long way since those days, and today’s Camaro is exceptionally powerful, over 300 hp, yet delivers fuel economy on par with some family sedans. Of course, this isn’t even a green car, so what about hybrid cars and clean diesels, for example? Industry experts tend to note that we’ve come as far as we can with powertrain enhancements, such as electrification, small-displacement turbocharged engines, and boxfish-inspired aerodynamics tweaks. So far, these developments have brought us ever closer to the CAFE standards, averaging 54.5 mpg by 2025, but something else is needed.
If car fuel economy is going to be won by anything, it’s going to be lightweight construction. Ford recently proved this with an all-aluminum body on its best-selling Ford F-Series, saving some 700 pounds off the original steel body, but it also said that it wasn’t considering the lightweight material for its automobile lineup, citing costs, which brings up why lightweighting is such a touchy subject. Paul Krajewski, General Motors Engineering Group Manager, remarks that the “biggest challenge is the cost / value proposition to the customer. We have methods to achieve CAFE standards, but they require adding cost to the customer.” Ford’s solution will be the implementation of more carbon-fiber and CFRP (carbon-fiber reinforced plastic), and General Motors has been toying with magnesium sheet metal.
Of course, improving vehicle fuel economy is mechanically possible, but another important part has to do with the consumer. Of course, some people spend more on “green cars” because it’s the responsible thing to do, but even those people balk at the more expensive, yet cleaner, options. Jon Riley, National Center for Manufacturing Sciences Vice-President of Digital Manufacturing, says of this change, “The biggest challenge to meeting CAFE standards will be the consumer cultural shift the necessary technologies will impose… People will have to get use to smaller cars made of advanced and expensive materials… and to styling driven more by aerodynamics than by market research.” Riley admits, however, that “these things may not be readily embraced.”