Don't Discount Diesel

For many Americans, diesel-powered cars are just another bad memory of the 1980s, like Milli Vanilli, fingerless gloves, and Mohawk hairstyles. Those diesels of yore were noisy, soot-belching vehicles that could barely outrun a Yugo out of the starting gate. But advances in technology have made diesel all the rage in Europe, where they'll account for more than half of all passenger cars sold this year. And auto makers such as DaimlerChrysler (DCX ) and Volkswagen hope to repeat that success in the U.S. after new federal rules requiring gas stations to carry cleaner-burning diesel fuel kick in this fall.

There's more at stake here than just some carmakers' bid to profit from a hot auto trend. The real attraction is the prospect of reducing America's use of transportation fuels, much of it imported. For example, Margo Oge, head of the Environmental Protection Agency's Office of Transportation & Air Quality, says the U.S. could save up to 1.4 million barrels of oil per day -- roughly the amount it imports from Saudi Arabia -- if a third of U.S. vehicles ran on diesel.

Domestic carmakers aren't so sure about such aggressive forecasts, noting that up to half of the fuel-efficiency advantage regular diesel engines enjoy over gasoline models could be erased by all the expensive gear and special catalytic converters needed to filter soot and scrub pollutants from diesel exhaust to meet U.S. emission requirements for cars. So it'll still be an uphill battle to revive diesel here, although clean diesel technologies such as the one unveiled recently by DaimlerChrysler should ease such concerns. But while the much-hyped clean diesel is unlikely to prove a silver bullet for solving the energy problem, the U.S. should certainly further investigate this -- or any -- promising technology that could help it regain energy independence.

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