Efficient driving for a 1,000 mile tank

Discussion in 'Gen 3 Prius Fuel Economy' started by bwilson4web, Jul 3, 2013.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

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    One of the first parts was to compare the odometer and true distance using both highway mile markers and GPS. So when I had to replace my tires, I resized them so the revs/mile matched mile marker and GPS within less than 1% error. Actually, slightly conservative as the indicated MPG is lower than true.
    Yes, provided you define these terms:
    • full tank to full tank - I let the tank run dry so the engine stopped. I did under-fill the tank by inverting the fuel handle.
    • all the idles - during the driving stunt, the idles were only when unavoidably stopped. My shift in schedules and route selection made this less than 1% of the minimum hour duration for each trip. See route descriptions above.
    • cold starts - every day was a cold start
    • evaporation - the fuel cap remained on the tank the whole time
    • fuel dilution - nothing I put in
    • etc. - not a precise engineering term
    • averaging over multiple full tanks - one tank is enough but if someone is willing to pay my labor rates, I would be happy to replicate this stunt as many times as wanted. It takes ~40 hours per test, 1000/25 ~= 40 hours, @$50/hr, my current pay rate. I've already done one but subsequent ones will need a 'Gertes' payment. But of course, this is negotiable.
    Bob Wilson
     
    #61 bwilson4web, Jan 2, 2016
    Last edited: Jan 2, 2016
  2. bisco

    bisco cookie crumbler

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  3. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Not mine!

    Bob Wilson
     
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  4. bisco

    bisco cookie crumbler

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    nope, go cans. i wish i had your patience.;)
     
  5. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Not patience, curiosity and it is the 'monkey on my back.' Strange as it may seem, I ask myself a question and sometimes can not put it down until I know. The funny thing is I'm OK if others choose to remain ignorant or deluded.

    My rule of thumb:
    1. Answer first for accidental ignorance
    2. Answer twice with sources, facts and data
    3. Third time, let 'reality' run its course
    I will try to help folks see reality but I don't quarrel. If someone chooses an alternate reality, after two attempts (i.e., turn the other cheek,) I can find something more interesting to investigate. They have already condemned themselves to the judgement of reality and it is . . . their choice.

    There is a reason why some users are on my 'ignore user' list. They have had their two chances (often many times more but perhaps short of 'seven time seven') but there comes a time when 'God must see the sparrow', which is above my pay-grade.

    Bob Wilson
     
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  6. kenoarto

    kenoarto Senior Member

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    What techniques do you use to get 55 mileage? Speed, RPM, etc. Do you pulse to 41 and glide to 15? Yer killin' me! How do you do that you rotten bastard?!? ;)
     
    #66 kenoarto, Feb 29, 2016
    Last edited: Feb 29, 2016
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  7. bwilson4web

    bwilson4web BMW i3 and Model 3

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    • 1-1.5 miles - drive as slows as traffic allows (cut through 25 mph neighborhood;) take early routes that avoids stops, and; when possible, shift to "N".
    • 8.5-9 miles - follow slowest traffic using cruise control for a constant speed
      • do not accelerate going up-grade
      • accelerate going down-grade
    • 38 mph is optimum speed - fully engages hybrid mode (follow slow traffic)
    These three rules will achieve 90-95% of the optimum MPG. However, there is a longer list of subtle rules that have an impact at the margins:
    • shift into "N" when engine is off and no following traffic.
    • early braking in "D" approaching a red stop light and no following traffic so it can change green before you get there
    • use 4 lane roads and change lanes so following traffic can pass and not tailgate
    I'm an efficient driver which means: NO pulse and glide except on limited access road with no traffic for testing. I drive on cruse control, all the time, and fortunately, I live on fairly flat terrain. Even in hilly and mountainous terrain, I used cruise control by using semi-trailer trucks as pacing vehicles . . . a lot of space so I can drive around road debris.

    Bob Wilson
     
    #67 bwilson4web, Mar 1, 2016
    Last edited: Mar 1, 2016
  8. kenoarto

    kenoarto Senior Member

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    • 1-1.5 miles - drive as slows as traffic allows (cut through 25 mph neighborhood;) take early routes that avoids stops, and; when possible, shift to "N".
    • 8.5-9 miles - follow slowest traffic using cruise control for a constant speed
      • do not accelerate going up-grade
      • accelerate going down-grade
    • 38 mph is optimum speed - fully engages hybrid mode (follow slow traffic)
    • shift into "N" when engine is off and no following traffic.
    • early braking in "D" approaching a red stop light and no following traffic so it can change green before you get there
    • use 4 lane roads and change lanes so following traffic can pass and not tailgate
    NO pulse and glide ... using semi-trailer trucks as pacing vehicles . . .


    ARRRRRRG!
    I thought 26-27 was the optimum speed! Why 38?
    1-1.5 miles how slow is your slow?
    1.5-9 miles at what speed? This is most of my driving -- I live in the city.
    "N" instead of glide?
     
  9. GasperG

    GasperG Senior Member

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    Short trips (<9 miles) won't get you high MPG no matter what you do, also winter will make a HUGE difference compared to summer on those short trips.

    On my 12 miles commute, difference between summer and winter is 1 l/100 km (>10 MPG).
     
  10. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I thought 26-27 was the optimum speed! Why 38? - The hybrid transition speed is 42-46 mph depending upon vehicle warm-up and other factors. So I recommend using 38 mph make sure you're not transitioning through 42-46 mph and forcing unnecessary engine running.

    1-1.5 miles how slow is your slow? - Through the neighborhood posted at 25 mph.

    1.5-9 miles at what speed? This is most of my driving -- I live in the city. - These are posted 45, 50, and 65 mph:
    [​IMG]
    I recommend using Google or MapQuest to investigate alternate routes to your work. Try them until you find one that works best.

    "N" instead of glide? - Simple, easy, and works 100% without having to worry about anything else. But I grew up on manual transmission cars and have no problem with using the shifter to change gears. It is a skill that comes easy for me.

    Bob Wilson
     
  11. kenoarto

    kenoarto Senior Member

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    Fantastic explanation. Thanks oodles for taking the time to make a map.
    Here's my crib notes:
    1st mile -- 25 mph
    off hwy -- 38 mph
    hwy -- 51 mph
    Always use cruise control, always use N rather than Glide.
    Looks simple and quite doable!