Vanilla Option

The Fisker Karma has a sleek, luxurious look that seems to scream "future!" A sedan created by a former designer for BMW and Aston Martin, the Karma is a plug-in hybrid, much in vogue in these days of enthusiasm for all things green. After charging overnight from an ordinary wall socket, the Karma can run on electricity for up to 80 kilometers before a gasoline engine kicks in. The car, slated for production next year, probably turned more heads at the recent Detroit auto show than any other concept car. But good-looking as it may be, the Karma isn't likely to populate the streets in significant numbers any time soon. Like many of the hottest new green-car designs, it carries a high retail price tag—a cool $80,000.

The green auto revolution of the next 10 to 20 years may revolve around a far more mundane technology: the conventional combustion engine. After 120 years of engineering, it's hard to believe that engineers can wring any more efficiency out of the humble car engine, but they can. Partly because consumers of the last few decades put a greater a premium on power than fuel efficiency, there are a thousand and one incremental improvements—some of which have already reached the market—that can potentially turn the average sedan into a machine even Al Gore could love. Taken together, they can easily—and cheaply—boost fuel efficiency by 20 percent or more in the next decade. That's a faster and cheaper improvement than any green technology is likely to yield. "The internal combustion engine is fighting off the competition by improving," says Michael Omotoso, a forecaster with J.D. Power and Associates. "We don't really see it going away any time in the next 20 to 25 years."

The pressure to put greater numbers of gas sippers on the highway largely comes from consumers now balking at triple-digit oil prices and concerned about our toaster-oven globe. The European Union has proposed new legislation that would strictly limit auto emissions on the Continent, and already several European countries, notably France, are experimenting with tax rules that penalize carbon-spewing behemoths and reward compacts. Even the United States is now tightening fuel-efficiency standards.

The green tide of opinion has already lit a fire under engine designers, who are readying new technologies. For instance, gasoline direct injection, or GDI, delivers fuel more precisely by injecting it directly into the combustion chamber, rather than an intake manifold. (The technology has existed for years, but only now is being included in mainstream vehicles.) That provides an efficiency boost of up to 10 percent, according to an analysis done last month by the PricewaterhouseCoopers Automotive Institute. Turbocharging achieves similar streamlining by using engine exhaust that would otherwise be wasted to spin a turbine, making the vehicle 6 percent more efficient. Both have long been used in diesel engines (and some higher-end gas ones), but now are making their way to sizable numbers of gas cars. Ford has combined these twin advances in its new EcoBoost engine, which debuted at the Detroit auto show last month. Ford plans to roll out half a million EcoBoost engines annually by 2013—the kind of scale necessary to begin to make a meaningful impact on emissions.

There are other advances, too. Engines are most efficient when operating at a speed of about 2,500rpm (although it varies by vehicle), but variable valve timing, already available in many new cars, broadens that sweet spot by continuously adjusting the mixture of fuel and air. In 2006, Chrysler, Hyundai and Mitsubishi put the finishing touches on the last of five plants that can together produce up to 1.8 million of these engines a year for the three automakers.

The new emphasis on efficiency is visible even at the micro level. At Chrysler, for instance, engineers are urged to prevent "parasitic loss" from electrical elements—from speakers to seat warmers—stealing away more power than is necessary from the engine. That philosophy leads engineers to pore over schematics with a metaphorical looking glass. They zero in on energy vampires like the rear window defroster, which was forced to go on an electrical diet. Even the light bulbs had to become leaner, and Chrysler has switched most of its models to less energy-intensive LED lights.

Initiatives like this are one reason that auto researchers at MIT are cautiously optimistic that U.S. manufacturers can meet Congress's new mileage standards.

If auto manufacturers can satisfy government regulators and consumers merely by making incremental improvements to the gasoline engine and selling a few more diesels and hybrids, will that push back the day of arrival for a true auto-efficiency revolution? Could it be that the new standards don't go far enough? Maybe, says John Heywood, a mechanical engineer who led the MIT study. "But I don't think one should automatically assume that that's a bad thing. Since electric vehicles and hydrogen are iffy technologies, it might be a good idea to put our money into stuff that we know will be better. It might not be as much of an improvement, but we can get it out there in the near term in much larger volume, and the costs won't be as great." The green car of the future might be a lot like the car of today.