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effi
Well, a theoretical example:
compact car uses 13 hp to maintain 65 mph
the engine sweet spot is at 75 hp
so its producing 62 more hp at the sweet spot than it needs.
If you charge the batteries at 62 hp until they are full, then shut the engine off and run all EV i think you may get much better mpg.
So at 65 mph its getting an efficiency of say 20% since its not in the sweet spot, putting it in the sweet spot raises the engine to be 40% or so efficient.
13 hp x 400g/hp = 5200g; 3200g/gal = 1.625gal/hour 65 mph/1.625gal = 40 mpg which is around what the best fuel efficient cars get so these made up numbers arent too innaccurate.
Now 75hpx200g/hp = 15000g or 4.68gal/hour, if run for 30% of time, you would use 1.4gal, then 70% electric....well you saved (46kwh * 30%) * 80% efficiency =11kw if you get 250w/mi it would last you 44 mi, so 30% of 65 is 19mi + 44 mi = 63mi for 1.4 gal or 45 mpg that you went on that 1 gallon.
So 5 mpg better is what i might expect from this mod.
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