The Ford Fiesta ECOnetic, a small, sporty five-seater that gets an impressive 65 miles per gallon, will the hit the road in November — but only in Europe. “We just don’t think North and South America would buy that many diesel cars,” says Ford America President Mark Fields. The new generation of diesel cars, which are dramatically cleaner than old-school diesels and are at least 30 percent more fuel-efficient than gas-powered vehicles, haven’t managed to shake Americans’ longstanding aversion to the fuel: only 3 percent of cars in the U.S. are diesel-powered. But other automakers are betting that Americans can be swayed. Mercedes-Benz will by next year have three diesel vehicles on the market, and a handful of other automakers will introduce diesel models to the U.S. in 2010.