Quote:
Originally Posted by jamesqf
For the startup time issue, that's why you have the batteries. Your minimum battery requirement is whatever lets you to drive long enough for your SE to get up to speed, though of course if cost & weight allow, you can add more to add more plug-in electric range.
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You're dead straight on the SE principle, bigger difference more juice. You're still also dead straight that the SE burner alone would be greater(I agreed with you a post back) than the ICE.
The only issue I take with it is with the SE only you burn 5-10 minutes of fuel at 0 mpg. True you are moving but as far as the SE is concerned you are doing 0 mpg.
True also that you would get greater power with an SE burner.
But you still lose out because you either have to produce more energy than you use(to avoid having to heat the engine more to get to a higher speed) or you have to toss another 5 minutes worth of fuel at very low mpg to get up to that speed.
Yes the batteries could overcome the problem, but why waste fuel? Running it off ICE exhaust it will generate less overall power (modularly) but the amount its not generating the ICE is off fuel that would have been wasted for the first five minutes.
The reason to employ the ICE-SE combo is to achieve a smooth power delivery curve that's maximized for efficiency
I attached a paint image I sketched very quickly(and horrifically).
Blue is the ICE by itself
Red is the SE by itself
Purple is the ICE-SE.
The initial red trails blue because it takes the ICE less time to achieve 30%(almost instantly, but it takes it time to climb to optimum around 34-35).
The purple matches the blue exactly(it would actually be marginally higher) because at that point its operating just the ICE(the SE's are still warming).
Then purple and Red diverge from Blue because ICE maxes out at 35%.
The dip is presumeably an increase in speed where the stirling loses substantial FE but the ICE-SE still has the ICE dampening the loss. the Blue ICE line does not suffer noteably.
The graph assumes a constant speed with no interruptions otherwise you have more dips for the Red and Purple with the same effects. If the speed is variable above 10 mph the Red(SE) line will tank below the purple(ICE-SE) line.