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Strange - 0 MPG ??

Discussion in 'Gen 2 Prius Main Forum' started by adric22, Aug 24, 2010.

  1. adric22

    adric22 Ev and Hybrid Enthusiast

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    [​IMG]

    Notice the second bar completely missing? The strange thing is that the car was moving during that period. Here's what I did. There is a long stretch of downhill slope that is mostly a traffic jam right when I'm getting near my daughter's school. Usually the car would go into stealth mode most of this journey anyway. But today, just for the heck of it, I hit the EV mode button. I was in EV mode for about 8 minutes but used very little power being it was mostly stop-and-go downhill. But the car did move about half a mile during this time-frame. So I find it odd that it would show 0mpg. In fact, you can see that I even had some regen during that period.
     
    #1 adric22, Aug 24, 2010
  2. Rokeby

    Rokeby Member

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    The O MPG is a work-around so the computer doesnt have to deal
    with the mathematical impossibility of division by zero.

    In the case you gave (EV mode, ICE off);

    MPG =
    any number of miles/ zero gallons of gas =
    unsolvable =
    insert preprogrammed "0."

    Or maybe it has to do with the intractable; tomorrow^-2. :D
     
    #2 Rokeby, Aug 24, 2010
  3. BAllanJ

    BAllanJ Active Member

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    It would be better to indicate infinity with a full bar rather than an empty one in my opinion. I see empty bars in cases like this all the time, but my screen is in litres/100km. When I burn some gas without going anywhere it displays that infinity as a full bar, so I'm not sure why they chose this display style for mpg displays.
     
    #3 BAllanJ, Aug 24, 2010
  4. adric22

    adric22 Ev and Hybrid Enthusiast

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    Yes, but the odd thing is, I'm certain I've remained in "stealth" mode for an entire 5 minute section before and it displayed 99mpg. So I'm confused why it would should zero when in EV mode. There is no real difference.
     
    #4 adric22, Aug 24, 2010
  5. qbee42

    qbee42 My other car is a boat

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    It depends on whether any fuel was burned. The algorithm treats zero fuel and a small amount of fuel differently. I suspect the code looks for a value equal to zero to avoid the obvious error.

    Tom
     
    #5 qbee42, Aug 24, 2010
  6. ken1784

    ken1784 SuperMID designer

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    Following is copy of my post.
    -----
    The behavior is different between 2004-2005 model and 2006-2009 model.

    When there was no fuel usage at all and the vehicle moved during the 5 minutes period,
    the 2004-2005 model displays full (100mpg) bar on the screen and
    the 2006-2009 model displays no (0mpg) bar on the screen.
    That's the feature, not a bug. :)

    Ken@Japan
     
    #6 ken1784, Aug 24, 2010
  7. adric22

    adric22 Ev and Hybrid Enthusiast

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    You know.. now that I think about it, previous times I've gone more than 5 minutes in stealth mode was in my 2002 Prius. I've only had the 2008 for a few weeks.
     
    #7 adric22, Aug 25, 2010
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