It should be noted by all, tho, that the Prius gets some of its efficiency from using a Atkinson Cycle engine rather than a conventional Otto Cycle engine.
I think it also has an offset crankshaft. Now, if they would eliminate one cylinder, add a turbocharger, change fuel to diesel, reduce engine RPMs by half...they’d really be doing something.
Thanks for the information.
I believe Atkinson would roll over in his grave if knew that we are using his name on that engine. It is much closer to Miller cycle, but calling it a 100 year old design solves lots of possible patent issues.