(pls forgive the newbie engineering but)
Isn't the
https://en.wikipedia.org/wiki/Atkinson_cycle a "stroker" long throw engine which turns long-burn fuel efficiency into a lever onto crank#2 output for fast torque control of the crank output?
That stroker Atkinson is used in the Hybrid Prius but nowhere else today, but I'm not sure why.
Synthetic oils are much better today.