Yesterday's Mazda press conference mostly focused on its 2011 Mazda2 subcompact, but the company also dropped a bombshell.

Starting in 2012, it will sell a clean diesel version of its Mazda6 midsize sedan in the U.S. And it expects the car to return 43 miles per gallon on the EPA highway cycle.

Mazda press conference, 2010 New York Auto Show

Mazda press conference, 2010 New York Auto Show

The diesel will be part of the company's new line of high-efficiency Sky engines, which it will begin rolling out in new models next year.

The Sky-D line of diesel engines,  which it says will return fuel efficiency ratings close to those of today's hybrid vehicles, will make Mazda the first Asian company to offer U.S. diesels.

Other Japanese makers, including Honda, Nissan, and Subaru, have all delayed or shelved their plans to offer clean diesels as gasoline prices have stayed at or below $3 a gallon.

So Mazda's plans are ambitious, showing that it too will offer a range of green technologies--including the hybrids it plans to license from Toyota.

The company will also begin to replace its current gasoline engines with the new Sky-G engine, which it says is 15 percent more efficient--as well as 15 percent more fuel efficient.

[The Car Connection]