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Low inter city mpg

Discussion in 'Gen 3 Prius Fuel Economy' started by Manhal K Alrashdan, Sep 24, 2015.

  1. Manhal K Alrashdan

    Manhal K Alrashdan Junior Member

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    I'm a new prius Gen 3 owner. From what I read so far, I should expect higher Mpg when driving inside the city slow traffic than when driving on the highway. But what happens to me is the opposite. I usually get 55-60mpg on the highway using mostly cruise control, and only 35-40 in city busy traffic. My prius 2010 has 135k on her. Any explanation?
     
  2. bisco

    bisco cookie crumbler

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    that sounds about right, actually. it depends on the type of city driving, but heavy congestion will kill your mpg's.
     
  3. bwilson4web

    bwilson4web BMW i3 and Model 3

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    There are some threshold speeds:
    • 42-46 mph (67-73 km/h) - this is the boundary between hybrid mode when the engine can turn off and above which the engine has to run all the time. When possible, try to be below 42 mph or 67 km/h.
    Braking early and longer tends to improve energy capture by the traction battery. Braking harder and shorter is sometimes unavoidable but when approaching a traffic light, stop sign, or other traffic slow-downs, begin early so you can save as much energy as possible.

    Warm-up for the first 1-2 miles (1.5-3.0 km) uses the most amount of fuel on any short trip. As much as possible, try to take it slow and even consider shifting into "N" to coast during this time. The transmission is entirely electronic so shifting between "D" and "N" is safe especially if you have experience with a manual transmission car.

    Using "ECO" mode is reported to moderate the air conditioner. I don't have any data but reports are it will still cool the car but not as aggressively.

    Taxi or delivery use?

    GOOD LUCK!
    Bob Wilson
     
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  4. CR94

    CR94 Senior Member

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    We don't know your situation, but I'd guess excessive braking, short trips, congested traffic, or some combination. Also, what Bob said.
     
  5. Munpot42

    Munpot42 Senior Member

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    If you have a series of errands, go to the longest one first and work your way back home. That allows the car to fully warm up and stay warm for all your errands. Warmed up car equals best gas mileage.
     
  6. bisco

    bisco cookie crumbler

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    have you studied pulse and glide? of course, a/c can eat up mpg's.
     
  7. Anas Almustafa

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    I drive in jordan with a prius too and i see almost the same numbers for in city driving 35 to 40 MPG
    It seems when you're stuck in traffic and you have used up all your battery the engine will come one and will keep running until the battery is charged to a certain point usually more than 30% or so which then is used up and the engine turns on again and starts charging.
    ((( The Engine becomes the - only source of charging - the battery- slow speeds - very brief short braking - which kills MPG )))
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Also, Air Conditioning will tend to be less efficient in low speed city driving: there's less air flow coming through the radiator. Coupled with battery running down, then engine running constantly, as mentioned above.
     
  9. bwilson4web

    bwilson4web BMW i3 and Model 3

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    High battery temperatures can also trigger engine running. I first saw it this summer.

    Can you get instrumentation to measure traction battery temps?

    Bob Wilson
     
    #9 bwilson4web, Sep 27, 2015
    Last edited: Sep 27, 2015
  10. Manhal K Alrashdan

    Manhal K Alrashdan Junior Member

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    Thank you Bob,is it safe to shift to N while on the move, in manual cars, you can disengage the gear while descending down hill, to save gas. But is this feasible in the prius.
     
  11. Manhal K Alrashdan

    Manhal K Alrashdan Junior Member

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    Actually, we have 'nt any problem of warming up here in Jordan, as we have warm weather most of the year.
     
  12. Manhal K Alrashdan

    Manhal K Alrashdan Junior Member

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    Yes, I have, but you can't use pulse and glide on inner city bumper to bumper traffic.
     
  13. Manhal K Alrashdan

    Manhal K Alrashdan Junior Member

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    No, I can't. How can I do that?
    However, I doubt it's the case with me as my errands are short;less than an hour, and I usually run the AC which improve the cooling of the hybrid battery through the vent in the back seat.
     
  14. Manhal K Alrashdan

    Manhal K Alrashdan Junior Member

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    Thank you Anas, it's good to have fellow Jordanian in the forum. I,m also from Irbid.
     
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  15. bwilson4web

    bwilson4web BMW i3 and Model 3

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    1. MiniVCI - about $30 (USA) but requires a Windows XP laptop. The advantage is the Techstream software has all of the Prius known metrics. But it is not easy to run in the car because of the laptop and if you don't have one, it becomes an extra expense.
    2. Scangauge II - about $150 (USA) which runs by itself. There are XGAUGEs that are about as difficult to program as sending an SMS message on an old flip-top phone. It can display four metrics at a time so it is a good driving tool but it has no data recording capability.
    3. Android/iPhone apps - about $50-100 (USA) depending upon OBD interface. Derived from street-racer software, some hold a lot of promise and the ability to record metrics. I tried one but was not terribly impressed but it was a borrowed Android, software, and interface.
    Personally I like the MiniVCI because of the wide range of metrics and ability to record data. A small laptop can slip under the drivers seat. Not a 'driving tool', it is also a diagnostic tool if anything goes wrong.

    I drive with a Scanguage II and find it also meets 90% of my data needs. The lack of data recording is a problem since even if you use a camera, there is a data entry issue.

    I leave the Android/iPhone apps to others who are more committed to those technologies.

    Bob Wilson