I had no idea triple injection was a thing. According to Delphi, the first injection happens during the upstroke. The second targets the piston bowl. The third is approximately at TDC when temp and pressure are high.
Apparently, it stratifies the mixture (makes some areas unused) and allows more aggressive combustion timings for a given noise output. With 60% of the mix in the second injection, they got ~50% thermal efficiency... which is pretty awesome (even with the PM issues, atleast it's not NOx).
Thanks for posting this up.
LINK to Delphi paper. They did alot of single-cylinder testing and KIVA simulations. When I worked at University of Houston, I tried to get our KIVA program off the ground... but research funding was moving away from combustion modelling. Most of our stuff was live-engine with production sensors (and a few more).