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Full charge, coast downhill -> engine runs?

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by ntucker, Feb 12, 2013.

  1. retired4999

    retired4999 Prius driver since 2005

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    I'm pretty sure it starts and is using gas for the warm up cycle.
     
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  2. bisco

    bisco cookie crumbler

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    it burns gas because unlike the hatchback, the ice hasn't fired. so, when it spins to burn off electrons, it goes into warm up mode and burns a few ounces depending on outside temp. the problem is, if you do this everyday, it tanks your mpg's because you're in ev mode. it's not doing anything but warming up the ice each time.
     
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  3. REmmons

    REmmons New Member

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    I would buy the explanation that everyone else has shared that the battery is full and the regen has nowhere to go, but that wouldn't explain the horrible mileage you mentioned. What kind of mileage are you getting?
     
  4. ntucker

    ntucker Junior Member

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    Well, it is definitely running the engine, not just spinning it dead. So yeah, my mpg really is dropping on these trips. I think the reason the number gets so ridiculously low is that the engine runs the entire time in warmup mode, but I travel a very small distance (I just checked and it's .92 miles) at low speeds, so the gas put towards warmup is just wasted. If I slowed way down and just crept a few blocks but let the engine run for the same amount of time, the mpg would drop even further.

    ETA: just now I was walking home up the hill and saw my wife driving down the hill, having just pulled out of the driveway. She rolled down the window and waved, and I said, "hey, your engine is running." She gave me the finger. :D
     
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  5. retired4999

    retired4999 Prius driver since 2005

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    What Your Number 1 (y)
     
  6. ksstathead

    ksstathead Active Member

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    Charge by time when you know you are going downhill?
    This stinks. Still fine for my needs in flatland, but that would frustrate me if we had a hill.
     
  7. bisco

    bisco cookie crumbler

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    it's not an ev, that's what the issue is. and there has been a lot of confusion over this in the purchase and decision making process. i like ev as much as anybody, but it can take a little extra thought under certain conditions.
     
  8. ntucker

    ntucker Junior Member

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    Well, what would an EV do in that situation? It would use the brakes. It's not like slowing down without burning gas requires some kind of advanced technology the PiP doesn't have.
     
  9. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    Maybe it is more efficient and safer to use the engine. If you are going down a long hill you could overheat the brakes. Which is more important, mpg or safety?

    Mike
     
  10. bisco

    bisco cookie crumbler

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    i'm not disagreeing with you. that is what an ev would do i guess. it's not an ev.
     
  11. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    There are scenarios where the car will use engine compression braking rather than friction brakes if there is no battery capacity remaining for regeneration. This in and of itself does not require fuel, but I expect it will go through the warmup cycle first. What I am not sure of is whether it will then turn off the fuel completely. This is not just with the B setting. Sorry I don't have the exact scenarios.
     
  12. bisco

    bisco cookie crumbler

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    there are some old threads that cover this, done by people with scangauges.
     
  13. ntucker

    ntucker Junior Member

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    By the way, I tried this with the thermostat at 68 and my round trip mileage was 93mpg. At this point, I'm satisfied that the car is fine and I just have to let my wife strike a balance between her green guilt and her desire to have the car be 75 degrees at all times.
     
  14. retired4999

    retired4999 Prius driver since 2005

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    (y) :D
     
  15. mmmodem

    mmmodem Senior Taste Tester

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    If it were me I'd just drive up the hill a bit or around in a circle to burn off some EV before heading downhill. You'll eventually find the right amount to burn off without engaging the ICE downhill.

    When DW is in the car, I switch on the seat warmers.
     
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  16. lensovet

    lensovet former BP Brigade 207

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    i think you missed this in the multitude of replies to this thread (the vast majority of which were off-topic lol) – but to solve your core issue – just put the car into neutral before going downhill and this will force the car to use friction brakes.
     
  17. chesleyn

    chesleyn Active Member

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    DW -- damn wife? LMAO!


    iPad ? HD
     
  18. mmmodem

    mmmodem Senior Taste Tester

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    Darling!!!
     
  19. mmmodem

    mmmodem Senior Taste Tester

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    Seems a little dangerous driving in neutral and going downhill. I'd rather go in circles. Although that also seems rather idiotic. :confused:
     
  20. ntucker

    ntucker Junior Member

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    I think you missed that I said I was going to try that. ;) And it worked.