Hi
There's currently a lot of combustion system discussion across multiple threads with plenty of overlap/ duplication.
I thought I'd open a dedicated thread for ease of posting/reading.
Reading the debate so far, the 'aggregated rumour/discussion' seems to point towards:
* High overall pressure ratio
* Lean AFR
* Novel ingnition system - prechamber/jet/other
* Fuels optimised for energy and knock