While DaimlerChrysler's Jeep brand is touting its plan to build a Grand Cherokee with a fuel-efficient diesel engine, the automaker quietly ended production of a successful diesel version of its Jeep Liberty SUV for the U.S. market.

The reason? The engine for the compact SUV doesn't meet tougher federal emissions standards that go into effect next year, and Chrysler said it wasn't cost-effective to the replace the engine with a more modern version.

"The emission standards are becoming very stringent, and we weren't able to make a credible business case for a limited production vehicle," Chrysler spokeswoman Dianna Gutierrez told The Detroit News.