Not Your
Grandmother's Diesel

In gay parlance, words can have multiple meanings. Take diesel: It could be a brand of sunglasses, an action-movie star, or a surly gal whose wardrobe consists mainly of tank tops and motorcycle boots. And beginning this year, diesel could also mean the eco-friendly, fuel-efficient car parked in the driveway.

In the past 20 years diesel cars have fallen out of favor in the United States. They tended to be slow, make a lot of noise, and burp foul-smelling black smoke. That last quality caused the cars to fail the strict emissions standards in New York and California. In 2006 a new ultralow sulfur diesel fuel -- which removed the rotten-egg smell and lowered the emission of soot and nitrogen oxides -- paved the way for resurrection. And now, thanks to a big push from Germany's automakers, new diesel technology, including particulate filters and a diesel version of a catalytic converter, is making the engine even cleaner and more refined.

Only three automakers currently offer diesels in the United States: Mercedes-Benz, with its 3.2-liter turbodiesel V6 available in SUVs in the R, GL, and ML classes as well as the E-series sedan; Jeep, which uses a Mercedes-derived 3.0-liter turbodiesel V6 in the Grand Cherokee; and Volkswagen, which, for those on a budget, will bring the frugal 2.0-liter TDI engine option to the 2009 Jetta and Jetta SportWagen models this summer.

And the future looks even more diesel-inspired: Audi will introduce its diesel Q7 SUV and A4 sport sedan this year. Honda also has diesel plans for a fuel-miserly Odyssey minivan and Acura MDX SUV.

With gas prices steadily heading north, fuel economy is perhaps diesel's strongest selling point -- diesels get roughly 30% better fuel economy than gas engines. While the diesel Benz and Grand Cherokee offer gas mileage in the low 20s to 30s, VW promises to get it above 50 miles per gallon.