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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. PriusNeckBeard

    PriusNeckBeard Active Member

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    Ok, very small sample size, but thought I'd share any way.

    Today, for the first time ever, I really did all the Prius gas saving tricks.
    AND I did pulse and neutral-glide.

    From an between two locations 3.7 miles from each other:
    80.8 mpg in one direction!
    50.5 the other.

    I'm guessing the distances are too small for the Prius' mpg estimate to be accurate?
    (in addition to the 10% thumb on the scale it adds).

    OR...Am I on to something, potentially? JC. :)

    I did:
    PWR mode - nice brisk accelerations from stop and good steady ones on the straight-aways.
    4-lane in the suburbs for 3.5 miles of the trip each way, 30-42 mph.
    Coasted in to the few traffic lights perfectly - hardly had to use the brakes. I think I stopped at two traffic lights.
    There were three turns in each direction.
    There are some hills along the way. I.e. up and down, not referring to the elevation change. One big gentle up-down, and a smaller set too. Normally that hurts gas mileage, for me. I guess not much this time!
    An elevation change between the two end points, explaining some of the mph difference.
    Very light traffic - nearly total control of the roads
    About 75 degrees outside, though I was using A/C and headlights (night driving).
    Pulse-n-'neutral-glide' nearly the entire way. i.e. pulse up, put the car in neutral for the glide.

    Anyway the numbers were fun and thought I'd share

    The more I think about it, I just killed it from the lower elevation to upper and achieved the 50 mpg

    80.8 mpg the other way from the upper elevation to lower was awesome fun once I saw the display when turning off the car. Certainly elevation change has helped me before on other routes!, but not to this extent. ! LOL :) !!

    otoh...I may be on to a little something with this pulse-n-neutral thing (below 62 mph).

    Any ideas on this?
     
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  2. The Electric Me

    The Electric Me Go Speed Go!

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    Just pulse and glide.
    Don't try to out think the system.
    IMO it's dangerous to drive around with your vehicle in neutral.
     
  3. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    +1

    Neutral has zero advantage in a Prius that you can't get with a calibrated foot yet keeps all the downsides (and illegality) of driving in neutral.
     
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  4. Maarten28

    Maarten28 Active Member

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    3.7 miles is a bit short to take any conclusions. If you start with a full battery and end with an empty one in one direction then that will make a huge difference compared to starting with an empty battery and ending with a full one.
     
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  5. PriusNeckBeard

    PriusNeckBeard Active Member

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    True!

    Now *that* seems to make sense!

    Thx
     
    #5 PriusNeckBeard, Sep 27, 2017
    Last edited by a moderator: Sep 27, 2017
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  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Neutral doesn't charge the battery, so that's likely a short-lived mpg victory? This image immediately popped into my mind:

    upload_2017-9-27_6-7-31.png
     
  7. bestmapman

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

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    In my opinion, using neutral is a valid technique, that I occaisionally used. I used it when I had a long glide and I could take my foot of the pedal. For it to be useful, you must know that the ICE(internal combustion engine) is stopped. You need a scanguage or similiar device to ensure the ICE is off. If the ICE is running in the neutral position, then it is burning gas and defeats the purpose of using neutral. Also watch overspeed of MG1 ( I use 62 MPH, others may have a different number) for the ICE off.

    Here is a good read on the subject:
    Anything wrong with this technique....? | PriusChat

    BTW my 2010 had well over 200K miles on it with no apparent damage.
     
    #7 bestmapman, Sep 27, 2017
    Last edited: Sep 27, 2017
  8. drysider

    drysider Active Member

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    There are many threads on this going back many years. Neutral does a lot more than just take the car "out of gear". It also disables all of the Synergy system. That being said, keep us advised.
     
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  9. Mendel Leisk

    Mendel Leisk Senior Member

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    Come to think of it, Wayne Gerdes advocates shift-to-Neutral quite frequently, in this tutorial:



    (He's a bit over-the-top, my 2 cents. Think I'd rather just pay for the extra gas then be constantly using his techniques, lol.)
     
  10. Sam Spade

    Sam Spade Senior Member

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    AND it defeats some of the advantages of the hybrid design......like regen braking.
    While in N the hybrid battery won't be charged at all.....by braking OR by running the engine.
    That is false economy.
     
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  11. bestmapman

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

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    Sorry, but I must have misread the posts in the thread somewhere.

    I don't see anywhere anyone is advocating about braking while in neutral. Not charging or regening is exactly the state that is desired in a glide position. Also I don't understand why are you concerned with "running the engine" in neutral. It makes no sense to do that either.
     
  12. MelonPrius

    MelonPrius Senior Member

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    Do we have new hypermiling definitions? I always thought "Pulse and glide" was decribing "pulse and neutral glide with the engine off". At the least, it meant, pulse and neutral glide". With the foot pressing the pedal slightly, the Prius goes into neutral, and often with the engine off, in the Prius.

    Pulse and Coast is simply taking your foot off the gas completely after reaching your desired speed (leaving the car in D). In my experience, that doesn't work as well because of the engine braking- although it helps regenerate the traction battery.
     
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  13. WilDavis

    WilDavis Senior Member

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    Nope! ...sounds like a really stupid, dumb idea to me! (What the hell were you smoking when that gem came to you? o_O:rolleyes:;))
     
  14. Sam Spade

    Sam Spade Senior Member

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    And that conclusion is arrived at with blinders firmly ON.

    Sometimes it will be necessary to brake while in a "glide" cycle. If you do that in N, no energy is recaptured.
    Also just slowing down by releasing the gas pedal completely results in a little regen.

    Thinking that YOU can do a better job of energy management than the car does is.......egotistical for some and unnecessarily stressful for others. For all it is a small distraction to your driving attention that is not a good thing.

    Just my opinion.....as I am sure that you will be able to rationalize whatever it is that you want to do.
     
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  15. fuzzy1

    fuzzy1 Senior Member

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    I was a regular on his site at that time. My memory of reports from that event was that he was having drivers use Neutral as a reference point for what a proper glide feels like, and as a gliding shortcut during their short training shifts. Longer term, they were supposed to keep the car in Drive and use the calibrated foot method of gliding. But with limited ride-along time and plenty of material to cover, Neutral was a temporary shortcut so they didn't waste valuable lesson time trying to perfect just the first item.
     
  16. Mendel Leisk

    Mendel Leisk Senior Member

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    Ahh. Yeah it's much simpler (in my experience) to just touch the gas, if regen's imposing too much drag.
     
  17. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    Yes but there will be a time when you will have to brake, and better to be in D for that.

    Yes it does. When the Prius is in neutral is disables the engine from starting. The Prius, even when gliding, consumes 300W+ of power minimally. With the air conditioner on, it could be much much higher. This is fine, it will all work as it should but the hybrid battery is supplying the power. When the battery gets low to 2 bars, the car wants to start the engine to get it back to its happy place. But you being neutral have told it to hold on, I am overriding you. This is OK for now. Then it keeps draining the battery and gets to 1 bar. It really really really wants to run the engine now to get the battery back into the happy zone, but again you won't let it. There will be no warnings, no indications, nothing, just an unhappy car. Eventually you will bypass the lower safe zone of the battery. At this point the car will light up and tell you to shift the car into park or neutral as there is a hybrid system malfunction. The malfunction is the human preventing the car from keeping the battery happy. It will still continue coasting though. If you can keep your coast up like a long gradual downhill pass, you may get to the point where the battery is so discharged it cannot spin the engine back up when you do finally put it back into drive and now you have the chicken and egg problem. You need the hybrid battery to start the engine to charge the battery. But the battery is so low in charge it can't start the engine. Now you need a very expensive grid charge to get the car back.

    None of that is required when you just move your foot gradually while still in D. It is not hard to learn and you can glide as if you are in neutral without being in actual neutral. That's one of the benefits of having a single static gear that never disengages. "Neutral" is a state of mind, not a physical connection.

    "Pulse and Glide" and "Pulse and Coast" are the same thing said 2 ways. Both refer to (originally) as getting no arrows of flow on the energy screen of the MFD. Which is what neutral feels like. The advocacy was to try out neutral to see what it feels like, but then modulate your lead foot on the go-pedal to emulate that feeling. Takes a little practice but becomes second nature.
     
  18. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Ohio does not have a Law about coasting in Neutral, but a great many states do, (Largely dating back to manual transmissions but still on the books)

    This article is about N at a red light (also a bad idea) but list many states where coasting in N is illegal.
    united states - Is it illegal in any U.S. jurisdiction to be in neutral at a red light? - Skeptics Stack Exchange

    (I am 61, I have only been pulled over for coasting in N once, in 1983 in WA. Manual transmission, Mazda GLC; i have been saving gas for a long time)
     
  19. WilDavis

    WilDavis Senior Member

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    These stories about coasting in "N" reminds me of an early driving experience shortly after I first moved here (USA) fron the UK, back in 1983. One of the young software engineers I worked with had just taken delivery of a brand new BMW 318 of which he was very proud, and so offered to drive us to the local sub-shop for lunch. I couldn't help but notice his habit of putting the car in neutral whenever possible (it had a manual gearbox) and I asked him why he did so, he told me that was how he had been taught, and it saved gas! :eek:) I kept my mouth shut, but it wasn't just his driving ability which immediately went down in my estimation at that point! ;)
     
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  20. fuzzy1

    fuzzy1 Senior Member

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    How did the occifer know?