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What is your DTE after fill-up?

Discussion in 'Prime Fuel Economy & EV Range' started by Salamander_King, Oct 8, 2019.

  1. Selbyevers

    Selbyevers Junior Member

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    My DTE doesn’t seem to update until after I have driven a few miles after filling up so I tend to forget to look at it, but after filling up today and driving quite a few miles it showed 594 miles. I’ll have to remember to keep an eye on it.
     
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  2. Salamander_King

    Salamander_King Senior Member

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    You are correct that the car does not update DTE immediately after the fill-up at the start. But in my experience, it is not very long before it updates it. I usually fill the tank, and turn on the car, wait 30 sec, then turn it off, then turn on again. This usually updates it.
     
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  3. fuzzy1

    fuzzy1 Senior Member

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    The fuel level sensor experiences a lot of slosh, so the computer likely needs to take time for a good series of readings to be averaged together for a usably accurate estimate.

    An OBDII-port monitor (I have a ScanGauge-II) will show the raw unfiltered fuel sensor reading, revealing how much slosh happens.
     
  4. Gokhan

    Gokhan Senior Member

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    The DTE for my fifth fill for my 2021 Prius Prime Limited Blue Magnetism (Spirited Aqua Metallic) is 679 miles. I still haven't reached 700 miles.

    I only do long trips on HV. I turn on HV when I reach the main street so that I don't waste fuel idling—typically after 1–2% of SOC use. Usual hypermiling tricks such as gentle acceleration, avoiding braking as much as possible, maintaining speed, setting the A/C near ambient temperature, avoiding speeds over 60 mph (62 mph on the speedometer), and trying to synchronize with lights, which seems to work better if you drive well below the speed limit.

    [​IMG]
     
  5. PiPLosAngeles

    PiPLosAngeles Senior Member

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    In the Los Angeles area they long ago ditched the concept of synchronized lights. More often than not you hit about 75 - 80% red lights. It can be mildly infuriating, especially in special cases where there are multiple traffic lights in a short distance. There's one spot with three traffic lights within about 200 yards and why they haven't bothered to make sure they're timed to prevent gridlock escapes my imagination.

    Anyway, I've noticed that driving significantly faster than the speed limit reduces the frequency of red light encounters. I've always wondered if this was intentional to boost ticket revenue.
     
  6. jerrymildred

    jerrymildred Senior Member

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    Same here. More than mildly infuriating imho. They say they want clean air and and then make drivers spend all their time either idling/braking or accelerating.
     
  7. PiPLosAngeles

    PiPLosAngeles Senior Member

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    And true to form, rather than make the relatively small investment required to reap huge emissions gains, they punt. It becomes the auto manufacturers that have to research and develop space age materials and technology to reduce emissions and consumers who have to pay the increased prices just so the decision makers won't have to get out a stopwatch and a calculator and manually set some traffic lights.
     
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  8. jerrymildred

    jerrymildred Senior Member

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    I don't think most drivers care. Around here, at least, they race past me in a tremendous hurry to get to the light in time to stop and idle for a while. Then, when the light turns green, they just sit there messing with their phones.

    The most fun part of my job as an industrial electrician was line control. That meant getting the conveyors starting/stoping at the right times, running the right speeds, accelerating/decelerating at the right rates so that the machines making the cans stopped as seldom as possible. I always thought it would be a neat challenge to do that with traffic. The hard part is that cans are a little more predictable than drivers. Well, I guess it's usually a safe bet that some of them will do something stupid. :D
     
  9. Gokhan

    Gokhan Senior Member

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    DTE after the sixth fill: 715 miles

    Vehicle: 2021 Prius Prime Limited Blue Magnetism (Spirited Aqua Metallic)

    What do you guys think about this DTE?

    I estimated my actual HV mileage after substracting the EV miles (using my watt-hour meter as an estimate) and using the actual fill-up gallons and driven miles to be just about 75 mpg. On the MFD, which seems to inflate by about 5%, I typically get around 85 mpg, and then there is typically a 5% battery SOC use in a 22-mile trip, which subtracts about 1.7 miles. So, about 75 mpg checks right.

    [​IMG]
     
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  10. road2cycle

    road2cycle Active Member

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    Wow, 715 miles DTE is insane!!

    I just filled up this morning, a few miles after the fuel light turned on, with 9.26 gallons. DTE after the fill up was 521 miles. So I’m getting roughly 56mpg out of the gas burner. The only time I run the engine is on the freeway (around 70mph) and slightly before I get to the freeway on-ramp.

    5C86EB3C-4BBD-417D-A004-4A0EB0338BCE.jpeg
     
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  11. road2cycle

    road2cycle Active Member

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    It’s been really nice not having to visit the gas station on a weekly basis like I was doing with the Tacoma. I just filled up this morning with 9.2 gallons (a couple ICE miles after the fuel light illuminated) and got 520 miles DTE. I’m getting around 56 mpg which is consistent with the previous fill up. I’m not driving it with any intent on reducing gas consumption, so I could probably squeeze a few more mpg out of this thing if I put in an honest effort.
     
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  12. Gokhan

    Gokhan Senior Member

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    DTE after the seventh fill: 732 miles

    Vehicle: 2021 Prius Prime Limited Blue Magnetism (Spirited Aqua Metallic)

    This is the newest PriusChat record! I was surprised because I was driving faster and my trip-mpg values were smaller. Nevertheless, the DTE still has increased. It looks like it's averaged over more than the last tank.

    [​IMG]
     
    #92 Gokhan, Jul 10, 2021
    Last edited: Jul 10, 2021
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  13. road2cycle

    road2cycle Active Member

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    I tried something new this morning filling up with DTE showing 50 miles remaining. After the fill up DTE showed 520 miles. So for this last tank I got 470 miles using 8.7 gallons of gas so roughly 54 mpg. My previous mpg was 55-56, but this is the first full tank having the HOV lane sticker so I have been driving faster on the way home from work which could account for the slight drop in mpg.
     
  14. fuzzy1

    fuzzy1 Senior Member

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    Never mind how much the DTE display changed, it isn't useful for this purpose.

    How many miles did your odometer or trip meter say you drove on that tank?
     
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  15. Salamander_King

    Salamander_King Senior Member

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    On the contrary to what you suggest, for a Prius Prime, the DTE number after filling the tank is very useful in estimating the HV mode only portion of the mpg from the last full tank driven. Of course, if one is driving a PP as a regular hybrid and never charge the traction battery, then your suggestion is valid. But if any portion of the last full tank driven includes the EV mode driven by charges from the wall, then DTE at the time of filling the tank gives a very good estimate of what the mpg of the HV portion of the drive was by dividing the number by the number of gallons of gas needed to fill it up which is usually around 9.4-9.3 gallon if one fills the tank at the time the empty light comes on.
     
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  16. road2cycle

    road2cycle Active Member

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    The trip meter includes miles driven in EV mode, which would skew the gasoline consumption calculation.
     
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  17. jerrymildred

    jerrymildred Senior Member

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    I suspect that @fuzzy1 didn't notice that the car in question is a Prime. For any other car, he would be right. All we Prime drivers have is just the estimate from the DTE. That and a ridiculously low cost per mile if we don't live in California or New England. ;)
     
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  18. fuzzy1

    fuzzy1 Senior Member

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    Jerry is right, I didn't notice that this was for a Prime.

    At least on a regular Prius, DTE is based on a weighted MPG for an undetermined number of past miles that don't correspond well to the most recent refill. So when refueling, if MPG has been changing due to changed driving conditions or usage pattern, then the DTE change won't match the miles actually driven. So unless the Prime fixed or improved something here, it will still have a similar problem regarding its gasoline miles.

    Though if that is still the best indicator you have ...
     
  19. Salamander_King

    Salamander_King Senior Member

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    I never paid attention to DTE on my previous Gen3, so I don't know how inaccurate using DTE was compared to the actual full tank ODO method on Gen3. For PP, it is quite accurate and sensitive enough to the change in driving condition so that it is always very close to the actual mpg as long as one uses the same gas pump and consistently stop pumping at the first auto-stop never overfilling, and tries to fill the tank as soon as the empty light comes on. I have actually compared calculated mpg by full tank method and DTE estimate without any EV driven miles on a full tank and they were within 5%. It gives a much better realistic mpg number than the mpg showing on the dash which can be as much as 10% inflated.
     
  20. jerrymildred

    jerrymildred Senior Member

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    Facepalm!! Why didn't I think of this sooner? We have a regular Prius trim 2 and a Prime. If I can talk my wife into it, maybe she will be willing to compare DTE with actual miles on a tank. It won't be very scientific, but it's better than speculation.
     
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