Quote:
Originally Posted by rmay635703
The conversion factor is overcome by being able to hold the motor at its one efficient point, other motors might behave differently but that one would not work for accelerating direct drive or driving at any point other than WOT.
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I'm not advocating unloading the engine, but if you want hybrid, the car is moving in a parallel system you can still charge batteries with the engine as needed, or assist with the load using the batteries.
From the site for that generator:
4.5kw output continuous (5kw max)
Consumption at 1/2 load 0.24 gallons/hour
Consumption at 3/4 load 0.30 gallons/hour
Consumption at full load 0.34 gallons/hour (4.5kw assumed?)
half load uses %71 of the fuel consumption as full load.
3/4 uses %88 of the fuel as full load.
So, like many engines, it likes full load, but it doesn't mean it is terribly rpm sensitive efficiency wise, most bsfc charts have a wider than taller island. And you can just use electric at those low speeds where it makes sense, no law against having a series sized motor on a parallel hybrid if the situation demands it.
But since we have a fuel consumption figure, lets look at the bsfc coming out of the generator:
.34 gallons is about 1.29 litres, or 1095 g of diesel, divided by 4.5kw is 243 g/kwh, when fully loaded, which is ok, on par with a saturn at peak bsfc.
But that is also fully loaded, and if the engine is capable of 200g/kwh then that is like a %20 penalty when accelerating (efficiently) and cruising, zero opportunity to recover it, plus rectification and controller/motor. You must pump up the batteries to load the engine during cruise, and eventually they get full. Parallel can far more efficiently apply the needed torque to the wheels and load /unload the batteries if that proves out, either when accelerating or cruising.
Unless all the mechanical/electrical electrical/mechanical conversions start approaching the same efficiency as a gearbox under various conditions, parallel wins, it is simply a matter of power management. Varying load is still a problem.
Series only is a glorified and lossy torque converter without lockup. PLEASE lets not make that mistake again!