re: Fuel economy -- Does the Prius appear to be self-braking?

Discussion in 'Gen 3 Prius Fuel Economy' started by jrlnc, Mar 2, 2011.

  1. jrlnc

    jrlnc Junior Member

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    I'm not sure this is a totally dumb question, but I have to ask it.

    Please note that I am not entirely new to hybrids (I was a Honda Insight II owner for almost 2 years).

    When I am driving and I accelerate up to my desired speed, I back off the throttle and it always seems to me that the Prius has more drag or "rolling resistance" than I would expect. Don't get me wrong -- it is still a very efficient car and I'm sure that Toyota has worked all this out. But it seems to me that without any throttle or brake input, on a totally flat road with no wind, the Prius would slow itself down more than it should. Could this be because the car by default goes into regen mode immediately when there is no throttle input?

    I have observed this behavior even when the battery SOC icon appears to be full. Is this a normal feature?

    Granted, I've only been driving the car for 2 months, but now that winter is almost over and we're getting somewhat decent weather I am focusing on driving more efficiently.

    I would appreciate any input from the sage wisdom of older Prius owners here.
     
    #1 jrlnc, Mar 2, 2011
  2. calirider

    calirider ECOmobile

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    You need to figure out the glide skill.

    As far as I understand when you are not touching either pedal it goes in to a light regn mode and does put drag on the rolling distance of the car. If you lightly touch the gas pedal then it will not go into that mode and you will be able to glide for a long distance without slowing much. Look up the "pulse and glide"
     
    #2 calirider, Mar 2, 2011
  3. GrumpyCabbie

    GrumpyCabbie Senior Member

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    I'm trusting you're not driving the car in 'B' (engine Brake for hills) rather than 'D' (drive)?
     
    #3 GrumpyCabbie, Mar 2, 2011
  4. jrlnc

    jrlnc Junior Member

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    No, I've only used "B" once when driving back down from a mountain range with an approximately 3,000 ft drop in elevation.

    @ calirider: I'm going to see if that makes any difference the next time I drive anywhere.

    I do enjoy this enjoy car. :) It's not perfect, but has a some character in addition to its awesome fuel economy.
     
    #4 jrlnc, Mar 2, 2011
  5. jdcollins5

    jdcollins5 Senior Member

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    You are correct in that when you take your foot off of the accelerator, the car does go in to a slight regen mode and you can feel the drag you mention. You can see this on the HSI display.

    In an effort to make the Prius "feel" like a non-hybrid car, this regen is simulating engine drag of a normal gas-only car.

    If you will "feather" the accelerator just slightly until the bar just comes out of the regen area, then this is what calirider is referring to as the glide in the pulse and glide. Most people like to use the ECO mode when doing this as the pedal is less sensitive to movement in this mode and makes this feathering easier to accomplish.
     
    #5 jdcollins5, Mar 2, 2011
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