alt Hacker NewsOne thing that always puzzled me was how the gas engines in hybrids were so efficient. Technology Connections has a great video explainer: https://www.youtube.com/watch?v=KnUFH5GX_fI
tl;dw: constant RPM and a weird stroke geometry where the power stroke is longer than the other strokes to extract more energy from the expanding gasses.
Replies
wow this seems like a great video and a channel overall. Following it.
That and Weber Auto's teardown of Toyota's hybrid drivetrain which is referenced by TC: https://www.youtube.com/watch?v=O61WihMRdjM
Yes, gas engines have very bad efficiency. The best way to run them is with constant torque and RPM, that is, charging a battery
And yes the Atkinson cycle helps
I'm surprised there isn't more effort to create hybrids in reverse--an electric car with optional gas generator. The gas generator could run at constant speed, never changing RMP, while the battery handles constant changes in acceleration. The idea is not mine. I've heard about it in China
> a weird stroke geometry where the power stroke is longer than the other strokes to extract more energy from the expanding gasses
A.k.a. Atkinson-cycle (1882): https://en.wikipedia.org/wiki/Atkinson_cycle