X marks the pinnacle because it blends the best of the Skyactiv-G engine and the Skyactiv-D diesel engine that sit below it, chief engineer Kota Beppu said a briefing here last week.
"It combines the advantages of both," Beppu said. "It was developed as the top-end engine."
Using a technology called spark-controlled compression ignition, Skyactiv-X promises to deliver the driving dynamics and clean emissions of a gasoline engine and the low-end torque and fuel economy of a diesel. Skyactiv-X is also combined with a mild-hybrid system to ensure linear acceleration and spirited driving.
How this will translate to U.S. showrooms is unclear. Mazda CEO Akira Marumoto said last week it is definitely coming to North America but declined to give a time frame. Mazda still hasn't clearly publicized plans to bring Skyactiv-X to the U.S. The redesigned Mazda3 hit U.S. lots in March with the 2.5-liter Skyactiv-G engine as its only option, for now.
Mazda may fear that talking up Skyactiv-X before its sales begin will hurt Skyactiv-G sales. Spokeswoman Yukari Hara said product announcements are closely tied to marketing plans.
Skyactiv-X is one of a slew of technologies Mazda Motor Corp. plans to introduce in a bid to move the brand more upmarket. Marumoto said this month he wants to expand the carmaker's offerings and widen the range of sticker prices its vehicles can command.