Hmm, I always thought that Atkinson cycle engines like they use in most hybrid cars[1] were, like "normal" Otto cycle engines, more efficient at low-ish RPMs, h

Hmm, I always thought that Atkinson cycle engines like they use in most hybrid cars[1] were, like "normal" Otto cycle engines, more efficient at low-ish RPMs, hence why cars tend to have low RPMs at freeway cruising speed. The figure in [2] is 2500-4000 RPM, which is definitely "normal" freeway RPM for most cars. [2] also talks about why engines like those used in most modern hybrids are not actually true Atkinson engines. 1. http://en.m.wikipedia.org/wiki/Atkinson_cycle http://en.m.wikipedia.org/wiki/Atkinson_cycle 2. http://www.curbsideclassic.com/blog/the-atkinson-and-miller-cycle-engines-not-exactly-how-they-started-out-to-be/ http://www.curbsideclassic.com/blog/the-atkinson-and-miller-...