Mazda will make significant changes to vehicle platforms to accommodate the Sky engines, which will be more powerful and fuel-efficient at lower displacements than the company's current engines.

The first Sky gasoline engine is expected to debut in the United States in 2011. A direct-injection Sky diesel is to appear in 2012.

Mazda won't say which vehicles will get the Sky powertrains first, but the entire lineup will have the updated powertrains by the 2014 or 2015 model year, a source said.

Mazda2: The smallest vehicle in the company's lineup debuted here this summer. The small 2011 five-door hatchback is powered by a 1.5-liter four-cylinder engine that produces about 100 hp and gets more than 30 mpg on the highway and about 28 mpg in city driving.

Mazda3: After a redesign for the 2010 model year, Mazda's highest-volume model is scheduled for a freshening in 2013. It will get a Sky direct-injection engine, but the timing is uncertain.

RX-8: Questions about the future of the rotary-engine sports car have been rumbling for months, and there are hints that Mazda may kill it. Don't count on it.

While no changes are planned for the 2011 RX-8, updates are in the works for a 2012 model to bridge the gap until a successor is ready for production, a source said.

Mazda's next-generation RX-8 is at least one model year behind schedule because of problems in developing a new 1.6-liter rotary engine, called the 16X. The 16X, Mazda's first rotary developed from scratch in nearly 20 years, isn't hitting emission reduction targets. The global financial crisis forced the company to shift priority to the Sky range of gasoline and diesel engines, needed to meet more stringent fuel economy requirements.

So don't expect a redesigned RX-8 until at least the 2014 model year.

Mazda5: The redesigned 2012 small minivan goes on sale in January featuring Mazda's Nagare design language. The new Mazda5 also will have an updated interior and a more fuel-efficient engine.

Mazda6: For the 2011 model year, the mid-sized Camry-fighter got new headlights, 17-inch alloy wheels, seat materials, interior trim and additional technology. A redesign, with at least one of the new Sky engines, is scheduled for the 2013 model year.

MX-5: The roadster is due for a freshening for the 2012 model year but likely won't get the Sky gasoline engine until later. A rumored 2012 redesign won't happen, a source said.

CX-5: The successor to the Mazda Tribute will complete the company's lineup of CX crossovers in 2012 or 2013. The Tribute shares a platform with the Ford Escape. The CX-5 will be based on a Mazda platform.

CX7: The mid-sized crossover will be offered in a new iTouring trim level for the 2011 model year. The CX7 is expected to be equipped with a gasoline or diesel Sky engine when it is redesigned for the 2013 model year.

CX9: Mazda's largest crossover is due for a redesign in the 2013 model year.