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Pulse & Glide: accel to 41mph or 45mph?

Discussion in 'Gen 3 Prius Fuel Economy' started by F8L, Jul 20, 2012.

  1. F8L

    F8L Protecting Habitat & AG Lands

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    After 6hours of pulse & glide yesterday I made some interesting observations regarding pulse speeds.

    I initially start using the 41mph top speed for my pulses out of sheer habit from driving my GenII. Then I remembered the GenIII has a 46mph EV speed limit so I started using 45mph as a top speed. Check out the results from my consumption screen and tell me what you think.

    First photo is pulse to 41mph and not using neutral.
    [​IMG]

    Second photo is pulse to 45mph and using neutral. The portion of time to the far right of the photo was where I switched back to 41mph pulse and no neutral.
    [​IMG]
     
    #1 F8L, Jul 20, 2012
  2. markabele

    markabele owner of PiP, then Leaf, then Model 3

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    To be honest I think this is just a function of taking slightly longer to pulse up to 45 instead of 41. Those dips just happened to be timed right to get more of the pulse than the glide. FWIW I don't think it would affect much one way or the other. That's just my new, uneducated opinion though.

    Another questions to ask you is...why didn't you glide down to about 17 or 18 mph?
     
    #2 markabele, Jul 20, 2012
  3. F8L

    F8L Protecting Habitat & AG Lands

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    Because the mpg axis doesnt go any higher than 100mpg I can't tell which method is more efficient so I stuck with the GenII technique. Because this was my first real serious effort at pulse & glide I stuck to one method as much as possible. I may try a lower mph in the future but even at these speeds I was easily getting a long glide vs. pulse. My pulse could take 1-2 tents of a mile but the glide could be 5-7 tenths of a mile. If I had better real time analytics that showed higher than 100mpg I could have tried different techniques.
     
    #3 F8L, Jul 20, 2012
  4. bisco

    bisco cookie crumbler

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    do you have more trouble holding a glide in the gen III vs II?
     
    #4 bisco, Jul 20, 2012
  5. F8L

    F8L Protecting Habitat & AG Lands

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    I did when i first started driving this car but now it's second nature.
     
    #5 F8L, Jul 20, 2012
  6. GruveeGuru

    GruveeGuru Moonstone

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    F8L, I am curious what your screen would show with 45mph and no neutral.


    iPad ? HD
     
    #6 GruveeGuru, Jul 20, 2012
  7. markabele

    markabele owner of PiP, then Leaf, then Model 3

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    I don't think he did use neutral.
     
    #7 markabele, Jul 20, 2012
  8. SageBrush

    SageBrush Senior Member

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    Justin, do you have a SG ? It will show you MPG > 99.9
     
    #8 SageBrush, Jul 20, 2012
  9. F8L

    F8L Protecting Habitat & AG Lands

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    I did for the segment you are looking at. I stopped doing it altogether when I saw the readout become so much more choppy.
     
    #9 F8L, Jul 21, 2012
  10. F8L

    F8L Protecting Habitat & AG Lands

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    The problem with the SGII is that it doesn't give the nice graph over time. The instant mpg should be 9999 in any case so I guess it doesn't matter but I can't wrap my head around the implications of the graphs becoming so much more choppy.
     
    #10 F8L, Jul 21, 2012
  11. SageBrush

    SageBrush Senior Member

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    I was thinking of the trip MPG meter. You will have to unplug/plug the device to 'zero' the meter, but it will smooth out the bars you are agonizing over ;)
     
    #11 SageBrush, Jul 22, 2012
    F8L likes this.
  12. walter Lee

    walter Lee Hypermiling Padawan

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    My experience has been that the 2010 Prius gets higher fuel efficiency (MPG) on a flat or downhill grade when the top speed of a Pulse and Glide (P&G) cycle is lower, i.e. I'm getting better fuel efficiency when i do a P&G with a speed range of 30-40 mph than if I do a P&G with a speed range of 35-45mph. In a Driving with Load (WL) cycle, I found that the Prius gets better fuel efficiency if the speed is increased only a few seconds/hundred feet before the Prius has to climb uphill. It is always better to get to your top speed quickly and early. Fuel efficiency drops as the speed climbs higher than 35mph (because of wind resistance) . Fuel efficiency also drops if the speed is set too high and the Prius must decelerate or stop. The most fuel efficient way to accelerate is from the top of a hill. My experience suggest that for about every +5 psi that tires are overinflated beyond the max sidewall tire pressure , fuel efficiency decreases about 5 mpg at about 55 mph but increases about 5 mpg at about 30 mph (on a flat dry smooth straight asphalt road, no tail/head/cross wind). Also turning at about 90 degrees at speeds greater than 20 mph will lower the fuel efficiency.
     
    #12 walter Lee, Jul 24, 2012
  13. F8L

    F8L Protecting Habitat & AG Lands

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    Here is a new screen shot after a short pulse & glide session on my way home today. I alternated between a 41mph and 45mph max speed depending on the conditions. I did not use any neutral shifting this time. I used 41mph many more times than 45mph but you get the point.[​IMG]
     
    #13 F8L, Jul 25, 2012
  14. markabele

    markabele owner of PiP, then Leaf, then Model 3

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    That's actually a pretty sweet accomplishment to get the whole screen 100+ like that. That's my next goal!
     
    #14 markabele, Jul 25, 2012
  15. F8L

    F8L Protecting Habitat & AG Lands

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    It's easy if you have 30min to kill and have a spot where you won't be bothered by traffic. Just follow my pattern to get the screen like that. Then alter the pattern to figure out what is best for mpg. :p
     
    #15 F8L, Jul 25, 2012
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