A New Kind of Boom - Mazda engine is 20 to 30 percent more efficient

[Onkel Neal]

Very cool, something new in auto engines

DIESEL CARS, NO longer popular in Europe, are definitely a pariah in the US. Americans never warmed to them, and VW's scheme to dupe millions of customers and pollute the planet didn't help. But diesels provide better fuel economy than gasoline engines, even if they do emit more pollution. The ideal internal combustion engine, then, would combine the efficiency of a diesel with the (relatively) lower emissions of a gasoline engine.
Automotive engineers have spent decades trying to build just such an engine. Mazda just announced it's finally done it.
The Japanese automaker says the Skyactiv-X will be the world’s first commercially available compression ignition gasoline engine. I'll explain the tech in a moment, but the big takeaway is Mazda claims the engine is 20 to 30 percent more efficient than its current gas engines, and at least as efficient, if not more so, than its diesel engines.

https://www.wired.com/story/mazda-in...activx-engine/