[quote=08kermit;161623]

To avoid mixed units (watt-hours, horsepower, BTU,
joules, calories, whatever), let's make up a universal energy unit I'll call
"Noodle" which applies to both electric and ICE domains.

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It seems like we're all trying to be armchair powertrain engineers, so I pulled out a couple of automotive engineering references and texts from the late 1990s. ( I have studied enough mechanical engineering and wrenched enough race cars to know something about powertrains).

Depending upon which branch of transportation, and which continent and which era you are in, the units of energy you use will vary. My references describe energy in units of Joules (Euros) Kw-hours (Euros and electrical guys), Horsepower-Hours (Yanks and Brits), and my favorite, "Coal-equivalent-tons" (probably you steam locos).

Here is an interesting assertion, based on a chart of typical 1985 carburetted engines: "As passenger automobiles are now designed, it is not possible to run on a level road at constant speed anywhere close to the regime of best fuel economy. To get closer to the BSFC [brake-specific fuel consumption, a measure of engine efficiency] minimum it would be necessary to reduce the final drive ratio substantially - that is, reduce the engine speed... normal overdrive does not bring the operating point very near the BSFC minimum." Indeed, for carb'd cars in 1985, BSFC min was around 70% of actual actual cruise consumption.

Nothing in my books about Atkinson cycle fuel injected engines, so I think its time to update my reference materials.