Mazda has announced that it has made a breakthrough in gasoline engine technology, and it will come in the form of Skyactiv-X (also known by its less sexy name, homogenous charge compression ignition, or HCCI). Mazda is claimng a 20 to 30% increase in efficiency compared to their current direct injection engines.
An HCCI engine attempts to operate a gasoline engine like a diesel engine, so instead of squirting fuel into a cylinder then igniting it with a spark, the fuel and air are well-mixed then compressed, with combustion happening simultaneously at multiple points within the cylinder. This allows the fuel to burn more evenly at a lower temperature with less particulates and nitrogen oxide in the exhaust compared to a normal gasonline engine.
— Ars Technica (@arstechnica) August 8, 2017
Mazda’s new engines will still use spark plugs since it will still operate as a conventional spark ignition engine in certain cases. Mazda has developed a system that will let the engine know when to transition between a spark ignition and when the use HCCI. The system has been named “spark controlled compression ignition.”
The HCCi announcement came as part of a wider announcement by Mazda regarding its long term sustainability plan. In addition to sprucing up the traditional gasonline engine with Skyactiv-X, Mazda also plans to start introducing electric vehicles and hybrids “in regions that use a high ratio of clean energy for power generation or restrict certain vehicles to reduce air pollution.”.
As of now, it appears that Mazda intends to keep its HCCI development to itself. That’s not to say that other automakers aren’t also exploring more efficient gasoline engines; at one point, General Motors, Volkswagen, Mercedes-Benz, Ford, Honda, and Bosch have all attempted to develop some form of HCCI technology.