While the rest of the world can opt for fuel-efficient gasoline and diesel four-cylinder versions of the 3-Series, the entry-level model in the U.S. sports a six-cylinder powerplant. Given the current concerns about climate change and the increasing cost of fuel, officials at BMW are now planning to add a four-cylinder engine to its U.S. lineup.

The move would almost certainly boost sales, since the European 320i, powered by a 167 horsepower gasoline four-cylinder is already one of the company's strongest-selling models. The engines planned for the U.S. will feature turbocharging technology, however.

The information comes from BMW’s U.S. chief Jim O'Donnell, who revealed at the 2009 Frankfurt Auto Show that the introduction of the powerplants, equipped with the automaker's next-generation twin turbochargers, “is the goal and we will do it.” The car will be available for sale in spring of 2012.

If successful, BMW intends on adding four-cylinder engines to its X1 and X3 crossovers in the U.S. as well.

O'Donnell explained that the move is part of the company’s goal to meet tough new fuel economy standards coming into the U.S. between now and 2016. In line with the new standards, automakers will have to boost the fuel economy of their fleets by 5% every year before a national standard of 35.5 mpg takes effect in 2016.

Rival Mercedes-Benz has already decided to bring four-cylinder cars, including its new diesels, to the U.S. and Canada in 2010, proving even luxury and premium brands aren't entirely immune from the more mundane considerations of efficiency.

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