In an effort to try and refine my crude theoretical model to make better sense / match the real world data collected.
In watching the 12V system load I regularly see it around ~300W. It goes up and down of course. It depends on what the instantaneous 12V load is. But ~300W from IMA to DCDC would still be about ~326W of ICE parasitic load, if it had to cycle through the IMA battery maybe as much as ~362W of ICE load.
I also tried to narrow down the ICE air pumping losses a bit. The best tool I have is to watch the IMA Volts and Amps while using MIMA to force the ICE to hold certain RPMs ( all while in fuel cut / FAS stationary in neutral ). From the IMA battery side it seems like about ~1 kw of electrical power per 1,000 ICE RPMs. The Actual Air Pumping losses would be less than this as the IMA system is not 100% efficient from battery to shaft. But I've seen studies showing the IMA system ( Motor + Inverter ) combined up to 92% efficient from DC battery load to shaft output. So the actual Air Pumping losses might be around ~0.92 kw per 1,000 ICE RPMs. At 31MPH in 5th gear that's about ~1,058 RPMs and about ~973W of parasitic air pumping losses.
The other interesting thing that came out of that was a better quantification of the air pumping losses ( and IMA Battery electrical consumption ) for running in MIMA-EV-Mode at low speeds. ie. MIMA up to ~10kw IMA assist to move combined with FAS to not use any fuel while doing so. Normally not much use outside of the worst stop and go traffic.
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