I'm not certain if the grooves are funneling the flame to the charge that's laying in the quench area or laying a path for that charge to squeeze out to where there's a flame...or a combination of both..
I've read several of these threads about these and have always wondered if the grooves were providing the path into the quench area for the flame, instead of the other way around, just like you say Larry.
Flame speed is order(5 to 20 m/sec) in a non-boosted SI engine. So the above question could be re-worded as: which is faster, flame speed or forced convection in the groove?
IMO forced convection (in the groove) will be much greater than flame speed so the flame won't penetrate the jet (initially) but the jet will feed the flame rather quickly and foremost; the by-product of the jet will be turbulence and that will also
help move the flame around.
The acoustic results are very interesting; EGT data taken at the same time would also be interesting. I will add that in an energy sense there is very little difference in the total energy between the with/without grooves, so there is not much extra power being made even though the grooved engine is quieter.
On the matter of more than one groove: remember that the more grooves you use, the less chamber surface area to squish, and therefore the less each groove can be forced. I understand placement of the groove(s) is key especially if you know something about how swirled the mixture is as the piston rises to TDC; IOW the groove probably always wants to be pointed twds the spark plug, but the angle used to get there can be good, indifferent, or bad depending on the direction of swirl.
Someone in one of the much-earlier threads made a comment that the groove method is probably a good thing to do on a head from the 1990s or earlier, especially for street use with pump gas. On race gas with newer heads, I'm not so sure.
I never could see how the area with the most distance (the groove) was supposed to "shoot" the fuel/air out. The widest gap approaching tdc would create less pressure than the rest of the quench area. Rick
See the "room full of basketballs" argument in one of the earlier (or earliest?) threads.
The flow in the entire squish region seeks to flow to the location of the least flow resistance. So if you provide a channel (the groove) then there will be a zone around the groove where the mixture will preferentially flow, and so you get a concentrated jet of mixture from the groove especially very late as the piston rises. The widest area (the groove gap) does taken away (as you said) from some of the squish area, so it's a compromise in design. You hope to gain more than you lose in power.
If it does help to speed the burn, then you could get away with using less spark advance and therefore absorb less work (and gain more shaft power) during the climb to TDC.... assuming it really does help.
On using the patented idea: it's published in the USPTO Gazette and it has a patent number --- that means (if the claims are written properly) that no one can gain fiscally from the idea without an agreement from Singh. But it also means that anyone can read the patent and try it for non profit use --- that's the point of patenting something and putting it in the public domain: to make it available to all so that progress occurs. Keeping it secret would inhibit commercial progress. FWIW.