Fuel Economy Gets Sexy
In the wake of the Prius--and sky-high gas prices--carmakers start finding ways to give us bang for our three bucks.
By Andrew Tilin

(Business 2.0) – Two years after its U.S. debut, why is Toyota's iconic Prius hybrid still so hard to get your hands on? It's no longer about saving the planet or projecting a greener-than-thou image. Nope, today it's all about $3-a-gallon gas. Fortunately, most of the smart automakers have noticed. After years of one-upping each other in an infantile game of whose-SUV-is-bigger, the car companies are finally working to develop more fuel-efficient engines--and not just pie-in-the-sky stuff like fuel cells. This year both Honda and Lexus introduced high-performance hybrids that get, relative to their impressive power, excellent mileage. Ford just unveiled its second hybrid SUV. Meanwhile, with little fanfare, a number of other advancements have already arrived or are just around the corner. Here's a look at the gas sippers of tomorrow. -- A.T.

Good Mileage

Those lucky enough to own the new BMW 760Li are driving the future today, and they love it: The 438-horsepower, $120,000 sedan gets better mileage and performance, courtesy of a "direct-injection" V-12 engine. Basically, BMW engineers redesigned the 760's fuel injectors so that they now squirt vaporized gas with such precision that the mist both cools the motor for added efficiency and combusts more rapidly for superior performance. Direct injection helps the car get 15 percent better mileage than its predecessor, and published reports suggest it has also increased the engine's power output by 5 percent. Audi, Mazda, Mercedes-Benz, and VW have also started offering models with direct-injection engines or currently have them on the drawing board. Estimated highway mpg: 22-32

Better Mileage

Last year archrivals General Motors and DaimlerChrysler became odd bedfellows in an attempt to beat the Japanese automakers at the hybrid game. The first result? GM's sleek Graphyte concept SUV, which was designed to house the new "two-mode" hybrid technology that--sure enough--adopts the best attributes of models from Toyota and Honda. Like the Prius, the GM/Daimler hybrid runs on batteries alone at low speeds. At highway clips, two compact, assisting electric motors relieve the accompanying gasoline engine of so much work that it can--like a Honda hybrid--deactivate half its cylinders while moving. When an SUV derived from the Graphyte debuts in late 2007, GM and Chrysler promise that its mileage will be at least 25 percent better than that of today's sport-utilities. Estimated highway mpg: 26-35

Best Mileage

Diesel engines are quieter and more powerful than ever--while continuing to deliver supreme fuel efficiency (up to 40 percent better than their gas-powered siblings). Trouble is, they spew a lot of pollution. So much, in fact, that they can't be sold in five states with stringent air-quality laws, including key markets like California and New York. Enter Mercedes-Benz's Bionic diesel concept vehicle, which is shaped like a boxfish for improved aerodynamics and, more important, runs crystal-clear thanks to the incorporation of "selective catalytic reduction." The Bionic's exhaust gets sprayed with precisely metered amounts of an ammonia-based fluid that neutralizes nasty pollutants by as much as 80 percent. SCR is already available in commercial trucks and could show up in Mercedes production vehicles, in all 50 states, within a year. Estimated highway mpg: 70

Pick Your Mileage

Toyota's next act may very well resemble the Prius's alter ego: The company's experimental Volta is an all-wheel-drive gas-electric supercar that, despite its 408 horsepower and ability to reach 60 miles an hour in four seconds, still delivers nearly 32 miles per gallon. And if that's not stingy enough for you, don't fret: It seems that Toyota is also considering mixing the muscle of the Volta with the economy of a Prius. Company officials hint that they're tweaking the hybrid software so that, with the turn of a dashboard-mounted knob, you'll be able to instantly switch your car from miserly all-electric mode to all-out high performance. "It's just algorithms," says Bill Reinert, Toyota USA's national manager of advanced technologies. "It wouldn't be much different than switching the channels on a TV." If Toyota pulls it off, you can bet that every other car manufacturer will soon be reaching for the fuel-efficiency dial. Estimated highway mpg: 32-100