DETROIT – After being very non-committal last year about whether it would offer a diesel powertrain in the U.S., BMW AG announces at the North American International Show here it intends to offer diesel-powered vehicles in the U.S. market in 2008.

The engine will feature state-of-the-art catalytic-converter technology and be able to meet emissions requirements in all 50 states, says a BMW executive.

BMW has a family of highly renowned turbodiesels, and about 40% of its vehicles worldwide are powered by diesels.

Nevertheless, BMW has been downplaying its interest in offering a diesel option in the U.S.

It also has been unwilling to join forces with fellow German auto makers Volkswagen AG, Audi AG and DaimlerChrysler AG in jointly developing and marketing a new generation of “clean” diesels using urea-injection technology to make the engines compliant with emissions nationwide.

The auto makers are marketing the technology under the Bluetec name.

Mounting competitive pressures may have changed BMW’s thinking. Klaus Borgmann, senior vice president-powertrain development, told Ward’s last spring BMW was not overly excited about the prospect of selling diesel-powered vehicles in the U.S., saying the auto maker feared offering diesel alternatives to its performance-oriented gasoline engines would make for few conquest sales.

He said that in the U.S., it might be difficult to fully recover the cost of diesel engines and their accompanying complex exhaust aftertreatment systems.

This concern may explain why the announcement was buried in the BMW’s executive’s presentation Sunday. He says BMW is working on a 3-tier strategy under the heading of EfficientDynamics.

The long-term focus, the executive says, is using zero-emission hydrogen as a fuel for combustion engines.

The medium-term strategy includes development of hybrid-electric vehicle powertrains, which it is co-developing with General Motors Corp. and DaimlerChrysler.

The third tier of the strategy is improving the efficiency and performance of its conventional gasoline and diesel engines.

dwinter@wardsauto.com