Quote:
Originally Posted by dcb
I don't think the question was about the transaxle as a whole, as there are numerous gear losses not being represented here, but it was in relation to the relative electrical power going through mg1 and mg2 and the battery. It was not clear if each motor and the battery had their own current sensors even, because you cannot infer one and then use that inference to measure efficiency (otherwise they will all be 100% efficient).
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Patience, there are more than one way to measure losses. Certainly current is interesting but it also needs voltage and these are pulsed and pulsed-width-modulated power flows. This poses an interesting technical challenge of trying to measure RMS values from a complex waveform.
For now, I'm after the 'low hanging fruit,' power generated and consumed ... the energy flow. The data is reasonably smoothed and will meet my interest. After all, it is measured in the field versus Appendix B of the Oak Ridge report, a lab bench test.
I'm also thinking about how to measure wheel torque and rpm via another channel. There are new strain gauges that make this entirely practical and affordable. I could either mount on a drive shaft, the wheel hub, possibly a lug-nut, or even tire strain sensor. Then
there are the
off-the-shelf solutions. Good, fast, cheap, pick two.
Bob Wilson