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Could 'Pulse and Neutral' be the new 'Pulse & Glide'?

Discussion in 'Gen 3 Prius Fuel Economy' started by PriusNeckBeard, Sep 27, 2017.

  1. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    I agree, if you brake in "N", no energy is recaptured. But why would you do that. Simply shift to D before or during braking and all is recaptured. Doesn't that make sense to you?

    Right, shift to D before or during braking. Easy Peasy

    This never happens during a glide. There is not enough glide time to run the traction battery down. Even during protracted downhill stretches. It just never happens. (Emphasize: NEVER) Even if it did get below 2 bars, just shift to D and all is back to normal.

    Agreed with the exception that the glide must have the physical condition of the ICE off or it is not a glide regardless of your state of mind. The "neutral" or "N" position is an alternative method that works, but only if the ICE is off.

    I was taught that the glide condition was:
    1) ICE off (You need a seperate RPM or other gauge to make sure the ICE is not running)
    2) No energy being used for propulsion or
    3) No energy being gained from regen.
    There are two ways to acomplish that. The first is by modulating the accelerator pedal to get the engine to turn off and then zeroing out the electric regen and propulsion, or the getting the ICE to go out and selecting "N". Both result in the "glide" condition.

    The energy screen does not indicate if the ICE is on or off on the Gen 2 or 3. The EV indicator does on the gen 4. Without the ICE off it is not a glide.
     
    #21 bestmapman, Sep 27, 2017
    Last edited: Sep 27, 2017
  2. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    Yes please do tell.
     
  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    #23 JimboPalmer, Sep 27, 2017
    Last edited: Sep 27, 2017
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  4. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    LOL
     
  5. MelonPrius

    MelonPrius Senior Member

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    I agree with what you've written. I didn't have a kill switch on my previous car, but would N glide with the engine on. I knew that officially wasn't technically considered gliding, but was the best I could handle.

    From what I read on other threads here, below 42 mpg, you have a good chance for engine off gliding. Over 42 mph, the ICE stays on. Not sure if that's accurate, but it's what I keep in mind when I hypermile on local streets.
     
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  6. Tideland Prius

    Tideland Prius Moderator of the North
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    P&G for long enough and your SOC will eventually run low because you're gliding to a lower speed (or even to a stop if you happen to time it well). The pulse part isn't enough to charge up the battery since the ideal way to pulse is to have the engine power going to the wheel as well as the engine power to MG2 to the wheel (as shown on the Energy Monitor). There shouldn't be any going to the battery (but why HSD does that is for efficiency and a whole different story).

    So if you are using A/C in the summer, the battery will drain because it's not being topped up by the engine or regenerative braking. I think a blend of techniques will work well - take advantage of your commute's topography and traffic flow to either maximize regen or to maximize gliding.
     
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  7. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    It depends on the gen. On gen 2 it is about 41 on gen 3 it is about 46 and gen 4 about 74,
     
  8. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    That is correct. Each circumstance is different. Go slightly uphill it is difficult to P&G. Also as your SOC (state of charge) is lower it is harder to get the ICE to go out and the ICE comes on faster. All these are variables that you have to take into consideraton for P&G. It is more of an art than science. Once practiced and mastered it yields significant results.

    P&G with a high SOC is much different than P&G with a low SOC.

    That was my point about the "N" position. There are times when it is useful and times when it is a waste of effort.
     
    #28 bestmapman, Sep 27, 2017
    Last edited: Sep 27, 2017
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  9. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    Note on P&G for people unfamiliar with it.

    P&G is a tool. It cannot be used all the time. It can be used very effectively in times when the conditions warrant. If utilized it will greatly increase your fuel economy during that period. That will increase your total fuel economy in the measured period.

    P&G is also more of an art than science and requires learning of techniques. My results increased with experience. I suspect everyone has a learning curve. The N position is the same way. It is a tool in the P&G bag to be used occaisionally when it is warranted. Like any tool you have to know when and where and how to use it.
     
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  10. Sam Spade

    Sam Spade Senior Member

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    No it isn't. It is a colossal pain in the nice person.
    But whatever you enjoy..........:)
     
  11. Grit

    Grit Senior Member

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    The only special technique with this drive summary is that it was under eco mode the entire drive. No neutral, stop n go traffic at 35 mph peak and no hills.

    15 min
    3.9 miles
    89.3 MPG

    IMAG1424.jpg
     
  12. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    I understand. It is not for you.
     
  13. Grit

    Grit Senior Member

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    You should include if this was right after cold start.
     
  14. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    As was mentioned earlier, short distances such as 3.9 miles is not a large enough drive distance to be meaningful. Post something with 200 miles in the 80 MPG range. That would be significant.

    I'm not trying to be mean here, but you could force charge your SOC and get that easily in the gen 3 over 3.9 miles. Or, just start with a high SOC and it will do the same.

    Just a note of interest for those who have never heard on force charging. How to force charge your battery (SOC) gen 2 and gen 3. You can increase your (SOC) by putting the car in D and hold the brake firmly so the car does not move and apple enough accelerator to to start the engine. This will increase the SOC. It will eventually stop charging as it reaches its limit. This limit usually is the top bar.

    You may say why would I want to do that. The point is, know what your car can do, so if you ever need it you can have it in your bag of tools.

    I used force charging one time. Unfortunately one evening, I had to sleep in my car. It was 90+ in the desert that night and I needed the A/C on. With the A/C on the car kept coming on to replenish the SOC as the A/C bleeds off the charge rapidly. It kept me awake as the eingine kept coming on. I forced charged the SOC all the way up and was able to get to sleep. Slept pretty well for a grumpy old guy after that.
     
    #34 bestmapman, Sep 27, 2017
    Last edited: Sep 27, 2017
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  15. Grit

    Grit Senior Member

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    Just wanted to show OP that we can get same results as the OP's, or better, without going to N and put his hv battery in jeopardy, and other people lives in danger. Didn't see that reply that way at all :)
     
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  16. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    Sorry, good point.
     
  17. MelonPrius

    MelonPrius Senior Member

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    Ok, thanks for the info. So, on my gen 3, I can actually go up to ~46 mpg, go into neutral, and the ICE could be off? Nice.

    On a side note, when I say neutral, I'm referring to using lightly my right foot to find that spot where there is no regen action going on. Is that a proper use of neutral with the Prius on this board? Either way, that's my glide.
     
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  18. Sam Spade

    Sam Spade Senior Member

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    NO. Confusing terminology.
    There is a notch on the shifter marked N for neutral.
    Any other situation is NOT neutral.
     
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  19. Grit

    Grit Senior Member

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    Improper.
     
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  20. MelonPrius

    MelonPrius Senior Member

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    Sam and grid,

    Thanks for the feedback. I'll have to go back and watch some videos again to get my terminology the same page.