When thinking about diesel-powered vehicles, most Americans will immediately think of massive 18-wheel trucks with their noisy engines and soot-stained exhaust pipes. However, modern diesel vehicles aren’t necessarily louder or more polluting than gasoline powered engine thanks to developments in both diesel engines as well as the diesel fuel industry.

Beginning December 1, 2010, service stations that provide fuel for highway use are mandated to sell Ultra Low Sulfur Diesel (ULSD) fuel. While the mandate has not yet taken affect, a recent survey by the Environmental Protection Agency reveals that 100 percent of the service stations supplying fuel for highway use are already compliant with this regulation.

By combining modern diesel engine technology with ULSD fuel, today’s diesel-powered passenger vehicles meet or exceed even California’s stringent air pollution standards. While ULSD fuel is slightly less efficient than its predecessor, a diesel vehicle is typically more fuel-efficient than a similar vehicle powered by a traditional gasoline engine. Taking things a step further, a diesel hybrid vehicle is going to be more fuel-efficient than a gasoline hybrid.

Although diesel cars are commonplace in Europe, they are far from common here in the United States. However, automakers may see an upswing in sales of diesel vehicles here in the United States thanks to clean diesel initiatives like the EPA’s National Clean Diesel Campaign and the attention that diesel-powered cars are receiving in the green motoring arena.

Back in 2008, the Volkswagen Jetta TDI earned the 2009 Green Car of the Year title from the Green Car Journal. This was the first clean diesel car to receive top honors from the organization. One year later, another clean diesel car took the top spot, this time it was the 2010 Audi A3 TDI. While new gasoline hybrids came to market in those two years, the Green Car Journal chose two clean diesel engines for recognition.

Although the Chevy Volt was named as the 2011 Green Car of the Year, clean diesel vehicles aren’t out of the picture. Two clean diesel vehicles made it onto Kelley Blue Book’s 2010 Top 10 Green Cars list, the Volkswagen Golf TDI and the BMW 335d.

While sales of clean diesel cars won’t top hybrid sales next year, it could still end up being a good year for diesels. Volkswagen has four clean diesel vehicles in its 2011 lineup: the VW Golf TDI, VW Jetta TDI, VW Jetta SportWagen TDI and the VW Touareg TDI.

In addition to the BMW 335d, the German automaker also offers a diesel-powered crossover, the BMW X5 xDrive 35d. Audi will continue to sell the A3 TDI, winner of last year’s Green Car of the Year award, as well as the Audi Q7 TDI SUV. Mercedes-Benz is also in the clean diesel business with its Bluetec technology. The ML350, GL350 and R350 are included in the 2011 Mercedes-Benz Bluetec lineup.

While no domestic manufacturers are included on the list of automakers offering clean diesel cars for 2011, the Detroit 3 will continue to sell diesel-powered pickup trucks to its faithful clientele. The European diesel market has a much wider selection of vehicles to choose from but if clean diesel sales increase in the coming year, automakers may decide to introduce new models to the U.S. market.