http://www.greencarreports.com/news/1111978_2019-mazda-3-to-feature-world-first-hcci-engine-for-efficiency-report

  Thanks for sharing. Fascinating. looks kind of fragile although it probably isn't. 14:1 compression is impressive. I'd like to see the Harmonic Drive internals. Kinda reminds me of the auto articles from the early 1900's. Inventors were everywhere and tried almost everything they could lay their hands on. To control engine speed, the cam lobes were cut on a compound angle. They would slide the cam endways to control engine speed. Variable valve lift and duration. This was prior to butterflies in the carbs to control the intake flow.