MPG in Hybrid Mode

Discussion in 'Prime Technical Discussion' started by CEJ, May 13, 2019.

  1. CEJ

    CEJ Junior Member

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    Thanks, Bisco. Appreciate the explanation!
     
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  2. Salamander_King

    Salamander_King Senior Member

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    So, I took another pic this morning. This is similar to what you have described. An arrow from unlit engine is going out to the motor only. This pic was taken right after switching to HV while still EV SOC remains similar to the last one with arrow going to both the motor and wheels. Only difference is that at this instance, I did not have my foot on accelerator at all, so the car is coasting. Obviously there is no energy applied to the wheels and regenerative braking is charging the battery indicated by the green arrow from the motor to the traction battery. Is this what you have seen?

    IMG_20190611_092152.jpg
     
  3. CEJ

    CEJ Junior Member

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    Bingo! You totally got it. This situation seems to occur intermittently for me as I am driving along, at least on shorter trips of a few miles. Be interesting to know if it persists on longer forays. I also just noticed as I was driving that sometimes the engine icon is lit when none of the three outward channels is lit up with orange. Wondering if this is one your famous "lag" things, where the engine light is about to catch up and go off or is it some kind of an engine warm-up deal. A friend sent me an interesting Utube video that discusses a bit the generator, which I will see if I can figure out how to upload later and send along (maybe you have already seen it).
     
  4. Salamander_King

    Salamander_King Senior Member

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    Yeah, the pic was during engine warm-up immediately after switching from EV to HV. I will see if I see anything similar happening on my long trip this weekend. When I mix EV and HV on short trip less than 40 miles, I try to keep the engine warm so that I don't have to go through the warm-up cycle more than once. But that is not always possible. After switching from EV to HV, and initial engine warm-up is complete, if you switch back to EV and stay on EV long enough, ICE will cool sufficiently so that if you go back to HV second time, it has to go through another warm-up. I am not sure if I stay on HV only long enough, do I ever see the engine icon un-lit and still showing arrow coming out of it.

    I might have seen the case you described "the engine icon is lit when none of the three outward channels is lit up with orange", but can't say in what situation. It could well be the lag period after the engine is warmed up as you said about to catch up and go off. I will watch for those events as well for my next long HV drive.

    This morning my EV range on GOM was 36.1 miles. New record for me. My actual EV range yesterday was ~35 miles give or take 1 mile error for there is no easy way to measure actual EV range when you switch EV-HV back and force.
     
  5. CEJ

    CEJ Junior Member

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    So I was just sitting at a stoplight for a half a minute or so and the EM depicted exactly the scene we have now both seen: engine icon unlit but one orange channel showing from the engine icon toward the motor and also the green channel from motor to battery. So how do we interpret this? The only logical explanation would seem to be that the engine is in a charging but non-propelling mode. No channels are shown moving out or from the wheels, obviously, since the car is not moving. One other fact: the EV icon on the EM was unlit suggesting that the icon regards the engine as "on" in this case even though it isn't providing any propulsion.
     
  6. Salamander_King

    Salamander_King Senior Member

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    My interpretation is the same as the one we have discussed above on the "lag" things, where the engine light is about to catch up and go off, but in this case, engine went off before the charge arrow. Or did the charge arrow continues on for the duration of time you sat at the stoplight? I can't explain it. In any case it is usually very brief for those strange combination of arrows and engine icons and EV icons are on or off. Maybe the computer inside of the car is not that smart after all, and getting confused just like us??? LOL :ROFLMAO::ROFLMAO::ROFLMAO:
     
  7. CEJ

    CEJ Junior Member

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    I think the charge arrow continued the whole time I was stopped and the engine light remained unlit. So I don't know if lag theory applies here. I still am fuzzy about the whole regen/recharge process. Is there a stand-alone generator attached to the engine or motor, driven by the engine and/or the kinetic energy derived from the wheels during braking or coasting which then replenishes the battery charge? Or is the motor itself being turned into a generator by being driven backwards by the engine or wheel energy? Or something else? I am probably more confused at the moment than the computer.

    Here's a link to the video I mentioned earlier:
    https://www.youtube.com/watch?v=BkET_SgtKRA
     
  8. CEJ

    CEJ Junior Member

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    After reviewing the video, it shows the generator to be separate from the motor and apparently the generator can act at times as a motor rather than the other way around.
     
  9. Salamander_King

    Salamander_King Senior Member

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    I watched the video you linked. Even though it seems to be published by Toyota as a part of technical PR, I do believe it is wrong. I think it is just simplifying the technology trying to explain it to lay people. I am no expert nor claim to be knowledgable about all the technical aspects of the Prius Hybrid system, but all of the technical explanations and information I have read state both MG1 and MG2 are motors as well as the generators. There are no separate motor and generator in the car. What the video diagram labeling "motor" is the MG2 which I believe is the main traction motor, but it is also a generator that captures energy by regenerative braking. What is labeled "generator" in the video is the MG1 which act more as a buffer between MG2 and ICE, and can also dual-function as a "starter" and "alternator (generator)". I might be totally off, but that's my understanding. I hope someone more knowledgable than I will chime in.
     
  10. CEJ

    CEJ Junior Member

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    That’s extremely interesting and I think in sync with what Jerry has posted earlier. Do you by chance have a reference that explains MG1 and MG2 in more detail?
     
  11. Salamander_King

    Salamander_King Senior Member

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    Do Google search. You will get plenty of information, I always start with Wiki for an overview. Although most of information you find about PRIUS Hybrid system online may not be specific to PRIME or the latest generation of PRIUS (Gen4), I think the principle of technology is very similar throughout generations of PRIUS in terms of how MG1, MG2 and ICE work together. Hybrid Synergy Drive - Wikipedia
    Also the video Jerry put on this thread is extremely informative. If you like to read the technical paper, this may be of some use, though it is beyond my comprehension or interest. http://www.ae.pwr.wroc.pl/filez/20110606092430_HEV_Toyota.pdf
     
    #211 Salamander_King, Jun 12, 2019 at 8:22 AM
    Last edited: Jun 12, 2019 at 11:13 AM
  12. jerrymildred

    jerrymildred Senior Member

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    This is about the ultimate in detail. It's a couple hours, but it's like going to school on your transaxle.
     
  13. Salamander_King

    Salamander_King Senior Member

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    Thanks Jerry. It will be my summer project to watch this video. 2 hour of technical lecture is not for a faint heart.:eek:
     
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  14. jb in NE

    jb in NE Senior Member

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    Please post a Cliffs notes version after you watch, to save us each the 2 hours.
     
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  15. Salamander_King

    Salamander_King Senior Member

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    That's if I don't fall asleep middle of the lecture. Growing up as the golden ages of MTV generation, any video longer than 3 min is usually beyond my attention span. :LOL::ROFLMAO::oops:
     
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  16. jerrymildred

    jerrymildred Senior Member

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    This one is more easily digested. Bottom line is that M/G 1 is where the magic really happens. ;)
     
  17. Salamander_King

    Salamander_King Senior Member

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    Yeah, that's the one you posted earlier on this thread in your comment #158. MPG in Hybrid Mode | Page 8 | PriusChat It was still long for me, but I did finish watching that one!(y)
     
  18. jerrymildred

    jerrymildred Senior Member

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    Oops! I guess that after a couple hundred posts in a thread some of us start to lose track. :oops:
     
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  19. CEJ

    CEJ Junior Member

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    I got this picture yesterday soon after starting out and switching to HV (all three outward channels from the engine lit up but the engine icon unlit--also the EV icon on the EM unlit). It took a couple of miles before the engine icon lit up. Your suggesting the energy was sending out energy to wheels and motor without being "fully" operational. So you think it is sending "some" energy out but not up to full capacity?
     
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  20. Salamander_King

    Salamander_King Senior Member

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    Yes, I think ICE while going through the warm-up cycle has reduced power but still sending some energy to the wheels and motor. At least during the warm-up cycle even after you run out of EV range, traction battery will keep providing power to the wheel. How long the warm-up takes seems to depends on ambient temp and maybe some other factors. I have had the warm-up to finish in less than a few miles in some day, but occasionally take much longer.
     
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