Acceleration Techniques for best MPG

Discussion in 'Gen III 2010+ Prius Fuel Economy' started by sixseat7, Apr 3, 2012.

  1. sixseat7

    sixseat7 New Member

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    So I just got a nice new Prius 3rd gen. The salesperson informed he of one oddity when driving. That to get the best mpg, after i get up to "cruising speed" I need to take my foot off the accelerator and then put it back on. When I am accelerating from a stop, I see the "MPG" indicator slowly trend down, sometimes to nothing as I ramp up my speed. The only way this doesn't happen is if I accelerate to 40ish over 1 minute (and the people behind me would no doubt kill me). When I do as he told me, after achieving some cruising speed, my pmg does jump to 100 and level off closer to 40-50 (assuming i can re find the sweet spot on the pedal).

    So my basic question is this. Do I hold the pedal to the floor, accelerate quickly to cruising speed, then do the off the pedal, on the pedal trick? Or do i have to accelerate more slowly to come up to speed, but still do the trick?
     
  2. krazypriuslady

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  3. qbee42

    qbee42 My other car is a boat

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    Accelerate briskly, but not pedal to the floor. Wide Open Throttle (WOT) is a special case where mileage is sacrificed to power. You don't want to do that.

    Tom
     
  4. Sabby

    Sabby Member

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    You should read this. I found it helpful early on

    HSI
     
  5. p00kienrayray

    p00kienrayray Active Member

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    Just look up the term "pulse and glide". That's what the dealer guy was talking about, and it's a commonly talked about process among Prius and hybrid communities.
     
  6. HaveNoCents

    HaveNoCents Conservative Tree Hugger

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    This is a pretty good video to watch.
     
  7. walter Lee

    walter Lee Hypermiling Padawan

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    Background: The salesman is referring to a hypermiling technique called Pulse & Glide, P&G. P&G can only be sustained when wind resistance/aerodynamic drag is not too strong so it works best when the Prius top speed is under 40 mph, when the Prius has is on a downhill grade, or when the Prius has a strong tail wind pushing behind it. If you donot have to stop for traffic, low speed glides of a P&G are extended by a very smooth road surface, a downhill grade in the road, overinflated tires/low rolling resistant tires, and a warmed up engine (the gas engine needs to be running for atleast 5 minutes). For speeds greater than 40 mph, P&G often is not effective so another hypermiling technique called Driving with Load, DWL, is often used instead because road are almost never completely flat. For completely flat superhighway roads, just to set cruise control (cc) at 55 mph and the Prius will achieve +50 mpg for trips over 20 minutes in normal driving conditions. Faster highway speed acceleration, use Normal or Power mode instead of Eco Mode.

    Answer: To optimize the fuel efficiency of a P&G session the ratio between the pulse-acceleration time/distance to glide-coasting time/distance should be greater than 1:3. For example, for every 1 minute that you pulse, you should be gliding atleast for 3 minutes. The longer you glide the higher your fuel efficiency so a P&G session with a pulse-to-glide ratio of 2:8 (2 minute acceleration and 8 minute coasting) would likely give better fuel efficiency than a 1:3 ratio P&G session.