Not headed to America yet but Mazda is bringing out its homogenous charge ignition engine.
https://www.foxnews.com/auto/mazda-has-a-revolutionary-new-engine-and-its-not-a-rotary
Sorry, Mazda fans, it’s not a rotary, although the company does have one of those in the works to use as a range-extending generator in electric cars. Instead it’s a technology that Mazda calls Skyactiv-X, which is an original take on a concept known as Homogenous Charge Combustion Ignition, or HCCI.
Coleman says the idea is to get a gasoline engine to work more like a diesel, where compressed fuel ignites all at once rather than spreading away from a spark, which is less efficient. Gas burns faster than diesel, however, and it’s tough to control its ignition in this kind of engine. So, what Mazda did was design a high-compression (16:1) motor that uses a small spark that goes off just before the fuel would auto-ignite, creating the extra pressure needed to set it off at the right moment.
The lean-running engine is also supercharged to pack as much air into it as possible for and even more efficient burn, especially at full throttle, and Mazda has combined it with a mild-hybrid system that gives the powertrain an electric boost under acceleration. Fuel economy is improved by about 20 percent compared to a conventional gas engine with the same displacement, which in this example is 2.0-liters, according to Coleman.
https://www.foxnews.com/auto/mazda-has-a-revolutionary-new-engine-and-its-not-a-rotary