Mazda Motor Corp. disclosed plans to introduce a next-generation engine called SKYACTIV-X in 2019. The company bills it as the world's first commercial gasoline engine to use compression ignition.

In compression ignition, the fuel-air mixture ignites spontaneously when compressed by the piston.

Mazda says that a proprietary combustion method called Spark Controlled Compression Ignition overcomes two issues that had impeded commercialization of compression ignition gasoline engines: maximizing the zone in which compression ignition is possible and achieving a seamless transition between compression ignition and spark ignition.

Compression ignition makes possible a lean burn that improves engine efficiency up to 20-30 percent over Mazda's current SKYACTIV-G, and from 35-45 percent over its 2008 gasoline engine of the same displacement.

With high efficiency across a wide range of rpms and engine loads, Mazda says the engine allows much more latitude in the selection of gear ratios, providing both fuel economy and driving performance.

Mazda says the engine is still under development and figures are subject to change.