Mazda says it has made a long-awaited breakthrough in engine technology

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Fresh on the heels of last week's tie-up with Toyota, Mazda announced on Tuesday that it has finally made a breakthrough in gasoline engine technology. Mazda is calling it Skyactive-X; we know it better as homogenous charge compression ignition, or HCCI. It should mean a 20-30 percent boost in efficiency compared to Mazda's current gasoline direct-injection engines, and we may well see it in the next revision to the Mazda 3.

HCCI engines have been one of those "if only" technologies for some time now. Kyle Neimeyer first covered the idea back in 2012 for Ars as part of a deep dive into new engine tech that could help meet looming efficiency requirements for automakers.

In essence, HCCI is an attempt to run a gasoline engine like a diesel instead. Rather than squirt fuel into a cylinder—done directly, at high pressure, in the case of Mazda's current gasoline engines—then ignite it with a spark, the fuel and air are well-mixed and then compressed to achieve the bang in suck, squeeze, bang, blow.