Mazda is pretty damn smart in figuring out a way to make it work well.

http://www.motoiq.com/MagazineArticl...-X-Engine.aspx

 

I think their genius is to not solve everything but to integrate where they can.

 

Actually Volvo has been a leader when it comes to HCCI engines but what I do would like them to explain is the following:
1) Transition from spark-ignited to compression ignited.
2) Noise control.... moving from flame-propagation to sporadic flame
3) Volatility of fuel and they could accommodate for it quickly.
4) Emissions associated with compression ignition. spray patterns....etc

 

I didn't know Volvo was the leader in HCCI. I guess that doesn't matter now.

 

http://jalopnik.com/i-drove-mazda-s-...t-w-1800874806


http://jalopnik.com/mazda-s-holy-gra...ely-1801820285

 

More detailed dive on a prototype:

http://www.roadandtrack.com/car-cult...-how-it-works/

 

I have a hunch that they figured this out while developing their next gen rotary engine.

 

... except they're still unable to meet emissions with the skyactiv-d, which means the entire right side of their road map is fantasy land.

 

At least they didn't go the VAG route.