Huh. That's interesting. I should have researched more before I started driving one of these just for fun's sake.
So, this model doesn't include the battery yet, that's an additional layer, but it shows a larger MG2 motor that is attached to the wheels; wheels don't turn unless that electric motor is turning. ok.
Murphy said: In normal operation if the engine is running it drives one electric motor as a generator and the current flow is to the other electric motor driving the wheels. If there is excess current available it also charges the battery.
ok. if in that model I kick the ICE to 2000 rpm, holding MG2 at 0, MG1 is spinning, but actually too fast (that's an aside interesting as I can sit in park with my foot on the gas at 3000 rpm, so there's something different between that model (prius) and our vehicle I think). But anyway, assuming I'm driving, maybe MG2 kicks in to get me to 25 mph. MG1 is spinning at 3391 rpm. So, the current flow is to MG1, which is driving MG2, correct? I don't know how to know if there would be enough excess to also charge the battery.
I'm further not sure how my pushing the gas pedal converts a signal to fire MG2 vs. ICE. Obviously it's dependent on how hard I'm pressing it, whether I'm on a hill, and battery charge level, but how those factors convert to this model I don't know.
I'm trying to bring this back to the question: if I have a 75% charged battery, and I coast down a hill, should a) the battery be charging up, b) is this kicking on the ICE to do so? and is that by design or indicative of a problem?
I would presume that when I'm coasting downhill, the ICE is off and no electrical motors need to be driving the wheels. I'm sure that betrays my naivety about how cars work. If that were true then you couldn't correlate it to the power split device model, because RPM would be zero on the motors, but speed would be positive. I suppose that with a positive speed downhill, MG2 is getting turned by the wheels? and thus MG2 is turning in reverse-- so maybe the battery is getting charged simply by that energy, sort of like regen braking? and the ICE is out of the equation?
I'm not sure, this clarifies some things and yet shows I need a deeper understanding.
Back to real world numbers, I filled up today and then spent a little time looking back through my mpg history. It's variable of course, I think my best tank ever was 38.5, soon after I acquired the car with about 40k miles. It's somewhat steadily fallen over the following 6 years and was hovering around 30 mpg before it just took another little nosedive in the last couple of months to 27-28. Which all adds up to this newest behavior, possibly affected by airbag recall and computer reset, not having a great effect on my gas mileage.
It does make me wonder a couple of things. First, in another thread someone posted the images showing how much available power they have to run in electric-- from the dead stop the line is barely discernible from 0. This matches my behavior and I think probably has for a while. Under ideal conditions, how high do you guys see that bar go? I have 7 notches in the "empower" view, I think it is. With the HV full, flat surface yesterday running at 15 mph, that bar goes only to the first notch. Thinking back on it, I'm not sure I've ever seen that (green) bar go any higher than 1 notch. Wish I'd paid closer attention. So-- are my batteries dying but none of my systems are telling me yet? Are there other tests I can run to know more about that, or must I visit another dealer to learn more? I'm afraid most of the time real-world driving conditions are severely limiting my car's use of its battery; my primary mpg gains are coming from the engine turning off at a stop sign or at a coast, not from the electric motor, driven by the battery, turning the wheels. I'll keep experimenting...