Neutral when stopped...fuel savings?

Discussion in 'Gen 3 Prius Fuel Economy' started by Author, May 31, 2010.

  1. Author

    Author New Member

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    The Prius is set up to "creep", even with the ICE off, when stopped. It's reasonable then that energy (battery charge) is be being consumed to provide this movement.

    Can we then expect battery charge savings (and hence fuel savings) by shifting the transmission into neutral at long lights? Is there a saving of transmission wear too?

    In my old Jetta TDI (automatic) the fuel consumption at idle dropped by 50% (according to my ScanGaugeII) when shifted into neutral at lights.
     
  2. qbee42

    qbee42 My other car is a boat

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    Press on the brake when stopped. This eliminates the simulated creep, so no energy is wasted. If you hold the brake down very lightly it is possible to draw some power when not moving.

    Tom
     
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  3. bwilson4web

    bwilson4web i3 and Prime

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    The 2001-03 Prius engine ran until the coolant reached 70C. Shifting into "N" when stopped appeared to reduce fuel burn by a measurable amount. However, that effect is gone in the 2010 Prius. I can't find any use for "N" as a fuel savings except to coast up to a light or stop sign.

    Bob Wilson
     
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  4. Author

    Author New Member

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    Thanks Tom and Bob...been wondering about that for a while.
     
  5. E-GINO

    E-GINO Active Member

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    Scangauge Xgauge "amp" (Battery Amps) tells me that shifting to Neutral when stopped, the absorbed current changes from 1,5 amp to 1,0 amp. Therefore, while waiting at the red lights, I usually shift to N.
     
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  6. Author

    Author New Member

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    Ciao E-GINO and thanks.

    I'll have to set up the amp gauge and try it. Five hundred milliamps doesn't seem like much, but over time could offer some fuel saving.

    By the way, what are you paying for a litre of petrol in your neck of the woods? Here, $ 0,981/L (Can).
     
  7. mand

    mand New Member

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    If if I have to wait for a longer time at the traffic light I just push the Park button and rest my foot and relax ( of course the ground level has to be flat or nearly flat to that you don't get a jerk when you let go of the foot brake after the P button is pressed).
    Mand
     
  8. fuzzy1

    fuzzy1 Senior Member

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    Nothing in the Prius transmission ever physically engages or disengages when you switch between D, N, and R, so these have no wear implications.

    Park does engage the HSD equivalent of a parking pawl, and B will spin up the engine faster, so these do theoretically have some wear potential.
     
  9. MJFrog

    MJFrog Active Member

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    Hmmmm. Sounds like a good recipe to get rear-ended...no brake lights to let inattentive drivers know you're stopped.
     
  10. E-GINO

    E-GINO Active Member

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    Well, honestly I cannot say "the drain is 0,5 Amps" because the minimum reading of the XGauge "amp" is 0,5 amp as well, i.e. there is no solution of continuity between 1,5 A and 1,0 A Xgauge readings. Anyway, for sure there is a loss, because the electric motor is contrasting the braking force applied, so some energy is converted in heat. Coming to your question, these times I pay for a liter of Premium (98 octanes) something like a whopping 1,44 Euros. This is another incentive to look for details, in term of economy... all in all, the hybrids economy performances are composed by little pieces of savings. And related fun....
     
  11. mand

    mand New Member

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    Thanks for pointing it out. I always put in P when I can see 1-2 cars stopped behind me and never when I am the only one or the last one at the traffic light. Yes it is dangerous as you pointed it out re inattentive drivers and no brakelight on.
     
  12. pablovv

    pablovv Junior Member

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    I see more electric consumption when stopped in a ramp, so when I reach 12 or 11 Kph I put N.
     
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