Seen a lot of pistons of that design at different booths at the PRI wonder the reason for all the designs in the top?
Direct injection piston. Just like diesel's, it promotes fuel mixture and controls the flame front.
I had seen a really cool animated gif of the spray pattern and burn, but now can't seem to find it.
But here is the Hot Rod article.
http://www.hotrod.com/how-to/engine/1501-direct-injection-is-the-future-of-efi/
