(thank you Tervuren)
It looks like the compression is varied by altering the height of the piston/rod/crankshaft.
So instead of a single location for the lobes/balancer/rods, the entire middle of the crank moves in an elliptical?
I've seen patents for mechanically lifting the piston-to-rod pin to vary piston height. Extra weight at the end.
Yeah I still don't get it.
-I don't get how that extra power (especially turbo kick) can be efficiently handled even to straight cut gears at high speed.
-Gear teeth wear down and make noise. Small contact area. Not a good look for LeMans.
-Lots of variable-compression techniques have been attempted:
https://nap.nationalacademies.org/read/21744/chapter/27
-And Infinity
https://www.caranddriver.com/features/g15084183/under-pressure-the-science-behind-infinitis-variable-compression-ratio-engine uses an intermediate crankshaft like the Prius
https://en.wikipedia.org/wiki/Atkinson_cycle
-Not applicable but worth noting.
The first 'long stroke' is very efficient for lower rpms.
The extra cycle is what I don't understand.
The "compression-power-exhaust" sounds like the first exhaust has left but there is still pressure in the cylinder with more squash.
Do they keep and use that stored exhaust pressure as another short-stroke under turbo?
How does the cylinder stay clean without using hydrogen/methanol/etc?