How They Can Squeeze More Miles From the Gallon

"This is auto mechanics, not rocket science."

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How can automakers make more fuel-efficient cars, as Congress is aiming to force them to do? The best rundown of the technology, and an analysis of how much it's going to cost you—or more likely, how much it will benefit you—is in a 244-page decision handed down this past September by a federal judge in Vermont.

Judge William K. Sessions was not ruling on the Corporate Average Fuel Economy law that Congress is about to overhaul, but on a parallel development that could become just as significant: California's effort, which could turn out to have the force of law across the country, to force carmakers to limit their greenhouse gas emissions. The easy way carmakers can cut carbon dioxide is by getting more miles per gallon, so the judge's look at the technology is relevant to CAFE.

The short version is that the judge agreed with California's expert witness, who estimated that the initial increased vehicle cost for consumers would be about $1,500. Not only would this be offset by about $5,000 in fuel savings over the car's lifetime, if fuel is $3 per gallon, but the judge said it is likely the premium would be only temporary. "The automobile industry has historically been very effective at improving the quality of necessary technology while decreasing its cost," he said. Sessions said the estimate by the automakers' expert witness, that more fuel efficiency would cost consumers $5,000 per car, was inflated because he had not considered these already available technologies:

• Gasoline direct injection/turbo. Allows a four-cylinder to replace a six-cylinder engine without significant sacrifice of power. Already popular in Europe. About 12 percent fuel economy improvement possible.

• Camless valve actuation. The valve motion is controlled by electrical or hydraulic energy instead of a camshaft mechanism. About 12 percent improvement possible.

• Tires with lower rolling resistance. A very low-cost option. Although it must be balanced with the need for traction, the National Academy of Sciences says a 1 to 15 percent improvement is possible.

• Reducing aerodynamic drag. Even the automakers' expert said it was an "almost zero cost" method, but he argued consumers would reject a more aerodynamic look. California's expert pointed out that small detail changes can make a big difference, which is why the large, square Lexus LS 460 is more aerodynamic than many cars on the market.

• Continuously variable transmission. An infinite range of gear ratios, as opposed to the usual four to six, improves power transmission efficiency. Already in use; one of the reasons the 2007 Nissan Altima has highest horsepower and fuel economy in its class. A 6 percent fuel economy increase is possible.

As environmental consultant Dan Becker said this week, "This is auto mechanics, not rocket science." Congressional vote-counters say that both the House and the Senate have the support to lift CAFE standards in votes they have planned this week, but this is Washington, after all, and the effort might still fail. It's wrapped up in a big energy bill that would also increase use of wind, solar, and other renewable energy for electricity, and the Senate GOP has vowed to filibuster and President Bush has threatened a veto. As usual, Gristmill is following this closely and has the likely veto letter here. Stay tuned to see if the Democratic leadership can hold together an effort to raise fuel-efficiency standards to an average 35 miles a gallon by 2020, the first increase in 30 years.