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Mpg deviation

Discussion in 'Gen 2 Prius Fuel Economy' started by lpf, Feb 15, 2022.

  1. lpf

    lpf Member

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    for the first time I Note deviation between the consumption on the screen and the consumption I get from Hybrid Assistant app. E.g. MFD says 5.2 l/100 and Hybrid Assistant 5.8 l/100. The later has been confirmed at the gas station.
    I don't know what the reason is but I suspect that the tank sensor sends wrong level?
    Thanks
     
    #1 lpf, Feb 15, 2022
  2. jerrymildred

    jerrymildred Senior Member

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    Not related to the fuel level sensor. It's because the system in all Prii is very optimistic in measuring the rate of fuel consumption against the distance traveled. Most people just mentally adjust what they see on the MFD to compensate. If you track the fuel use and miles over several tanks, you can get a pretty close approximation.

    But it's worse in North America. In the North American 2nd generation Prius, there's an extra complication that I don't think you have in Europe. We have a rubber bladder in the tank. It varies in flexibility as the temperature changes. That means that, in cold weather, the gas station pump often shuts off sooner than it would in hot weather.
     
    #2 jerrymildred, Feb 15, 2022
  3. lpf

    lpf Member

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    Thanks. I always trust the gas station, what is the fuel-up is exaclty what burned for the given mileage.
    On the other hand I've never noticed so much deviation in the app, as this time.
     
    #3 lpf, Feb 15, 2022
  4. jerrymildred

    jerrymildred Senior Member

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    #4 jerrymildred, Feb 15, 2022
  5. lpf

    lpf Member

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    23 months so far, 51,000km
     
    #5 lpf, Feb 15, 2022
    jerrymildred likes this.
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