I’m not saying it’s done. I have zero information to allow me to do that. It’s a hypothesis, just as your suggestion was. Do you think operating butterflies at valve train frequency is practical? I would think that since the plenum is permanently pressurised a physical separator wouldn’t be necessary. The return volume would only be a small proportion of the cylinder volume.Zynerji wrote: ↑Tue Oct 08, 2019 7:57 amHonda released the info about the intake runner butterflies. I speculated at the time that they were pressurizing the intake runner during the compression stroke, or backfilling fuel into the plenum.henry wrote: ↑Sun Oct 06, 2019 9:53 amI doubt anyone outside the engine makers is likely to know. In 5 years very little has been confirmed about the actual operation of these power units.NL_Fer wrote: ↑Sat Oct 05, 2019 9:00 pmThe FIA imposed a limit for compression ratio of 1:18 a while back.
Can anyone confirm they are using a Miller cycle, because 1:18 is very high for an Otto cycle, even without turbo.
Miller would be a logical choice, to reduce the amount of exhaust gas, these ultra-lean burn engines produce. Sure the MGU-H can harvest it, but direct to the crank would be the best.
A potential for Miller cycle would be to inject in such a way that some of the fuel/air is returned to the intake manifold where it could be mixing in preparation for the next cycle. This would help stratify the charge and emulate two injector jet combustion.
IIRC, lots of posters dismissed the concept out of hand. It's nice to read that it may have actually been done.