Rethinking Fuel Economy

The President is expected to sign the compromise Energy Bill today. If sustained $3.00/gallon gasoline hasn't already put fuel economy front and center for American consumers, the bill's landmark 35 mile-per-gallon efficiency standard for the entire new car fleet should do so, as auto manufacturers start to modify their product lines to meet the new target. A recent episode of NPR's Science Friday included a fascinating discussion of what is possible in this regard, but the most interesting portion of the program focused on the efforts of a group of engineering students and faculty who are rethinking the entire concept of the car for new markets. As important as it is for the US to shift toward more efficient vehicles, the opportunity in large emerging markets such as India is even more critical, before consumers' expectations there are locked into a status quo that cannot be sustained, globally.

Contrary to some disingenuous comments we heard during the debate about the 35 mpg CAFE Standard, it is simply not realistic to imagine that US consumers will be able to purchase essentially the same cars as today, differing only in their ability to achieve dramatically better fuel economy. Consumer expectations of vehicle cost and performance and the engineering solutions necessary to deliver an average of about 10 mpg lower fuel consumption are headed for a minefield of trade-offs. Something must give, whether vehicle size and weight, performance, or sticker price. Two of the main constraints on Detroit are our expectations of being able to accelerate to highway speeds in 10 seconds or less, and traveling roughly 300 miles without refueling, regardless of vehicle size. What could engineers create if those expectations disappeared?

The work of the Vehicle Design Summit (VDS) seems aimed precisely at that conundrum, targeting a developing-country market in which consumers are seeking personal mobility without such preconceptions, and for which the notion of a 12 mpg SUV that can accelerate like a sports car is entirely alien. Their first-stage prototype is anticipated to achieve 100 miles per gallon, using a plug-in hybrid architecture with a small, highly-efficient onboard generator capable of running on a variety of fuels. And because it won't have to go 300 miles at a stretch, the size of the engine and battery pack can be minimized. That reduces both cost and weight, increasing energy economy further. And that's a key point; from what I can tell, VDS isn't just trying to reduce oil consumption, but rather the entire energy consumption of the vehicle, including the "embodied energy" and greenhouse gas emissions of the manufacturing process.

Having cars such as the ones VDS is designing available for developing-country consumers, as they reach the income levels at which car ownership rates take off, will be crucial in managing global emissions and getting the most out of the world's limited supplies of transportation fuels. As daunting as it may sound, it may actually prove easier to create an entirely new concept of the personal vehicle that is capable of achieving an actual 100 miles per energy-equivalent gallon, compared to boosting the current American car to 35 mpg by incorporating energy from electricity or biofuels that is conveniently ignored or under-counted for the purposes of the federal fuel economy regulations.