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How to improve fuel efficiency?

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Lisa C, Aug 31, 2019.

  1. Lisa C

    Lisa C New Member

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    I've had my 2017 Prius a couple of months. The best mpg I got was 64.4 mpg on a one hour trip on the highway using the adaptive cruise control. It was very hard for me to trust the car to speed up and slow down appropriately, but I managed to hardly ever have to touch the brake pedal the whole time I was on the highway. What other tips can you give on how to get the best fuel efficiency without having to spend a lot of time watching the display?
     
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  2. fuzzy1

    fuzzy1 Senior Member

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    #2 fuzzy1, Sep 1, 2019
    Last edited: Sep 1, 2019
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  3. Tideland Prius

    Tideland Prius Moderator of the North
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    1. Ensure that your tires are properly inflated with the changing temperatures/seasons
    2. Use the climate control sparingly (summer and winter)
    3. Use Eco Heat/Cool to reduce power consumption
    4. Use S-Flow to “Driver Priority” for even lower power consumption of the climate control
    5. Drive the speed limit (50-60mph bets much better mpg than 70-75mph)
    6. Learn Super Highway Mode technique for lower speed highway driving (50-60mph) if you wanna use the displays
    7. Learn to control the power output with your accelerator rather than use cruise control (which means your speed may vary so use according to traffic conditions).
    8. Learn the multiple routes to/from work and see if one route has fewer stops/more consistent speed or if one avoids a hill and goes around it instead. Maybe one route has 45mph limits and it’ll only cost you 5-8 mins commute time vs. the interstate and its traffic.
     
  4. alanclarkeau

    alanclarkeau Senior Member

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    Good advice already - but in reality, 64.4 is very good. What speed were you doing at the time?
     
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  5. sam spade 2

    sam spade 2 Senior Member

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    Nothing. Drive like an old lady and don't worry about it. :ROFLMAO:
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Whenever no one's behind, getting irate, and you need to slow for a corner or a stop, coast to that slowdown point, as best you can.

    Keep an overly generous following distance whenever there's a car ahead. This allows you to coast through the excess distance when there's a slow down, and/or gives tailgaters a motive to get by you, out of your hair.

    Use a block heater.

    Consolidate trips.

    Use alternates when practical: walk to the corner store, for example.
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Amen.

    If I can add something sacrilegious these days, and especially if no one's on your butt: stay under the speed limit.
     
  8. Lisa C

    Lisa C New Member

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    For the most part, the speed limit was at 70 and I stayed at 70 except when traffic slowed down. I think I can credit the great mpg to the dynamic cruise control.
     
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  9. alanclarkeau

    alanclarkeau Senior Member

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    DRCC is great, I use it about 80+% of my driving. But you're right - you need to be alert to what it's doing - it's not as good as an alert human brain in an emergency.

    Actually any C/C will improve most driver's economy. It takes a very steady foot and concentration to get better economy than a C/C.

    64.4 mpg is good for 70 mph.
     
  10. Lisa C

    Lisa C New Member

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    I have read conflicting opinions on whether slow traffic is actually good for fuel efficiency for a Prius.

    "traffic is an opportunity. The constant braking recharges the battery, and gentle acceleration lets the gas engine stay dormant. Pay attention, pick the right lane, and you can work your way through a nice long traffic jam with nary an ounce of gasoline consumed."

    and

    "It's torturous with any car, and with the Prius, all the stops and starts to waste gas."
     
  11. Prodigyplace

    Prodigyplace Senior Member

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    What driving mode were you using? I find that if I use Eco mode the dynamic cruise control reacts too slowly. I usually use Normal mode. I find the dynamic cruise in PWR mode a little agressive.
    On downhill stretches I sometimes torn off the cruise control. Since the system does not know how long the down slope is, it tends to use B mode which reduces regeneration to the battery.

    At 70 mph you are getting 64.4 mpg in a car that is rated at 50 mpg for highway driving.
     
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  12. alanclarkeau

    alanclarkeau Senior Member

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    The best economy I've ever experience in PRIUS was in slow traffic using DRCC where the traffic (for 100+km) fluctuated from 30 to 80km/hr - about 3.2 l/100km. And the trip back was about the same. Frustrating if you're in a hurry - and makes one wonder if the term "Motorway" was dishonest - "fast carpark" would have been better.

    Hard braking, driving too close to the car in front, not anticipating the traffic ahead, hard accelerating will ruin economy.
     
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  13. fuzzy1

    fuzzy1 Senior Member

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    It depends on just how you deal with it. It can be tortuous, especially if you make a lot of quick starts and hard stops. Or it can be a great opportunity for low speed gliding, and pulse and glide, if you intentionally keep enough spacing to buffer the erratic movements around you and avoid as many full stops as possible.

    But "nary an ounce of gasoline consumed"? Not a chance, battery recharging is nowhere near that efficient, it will merely consume very noticeably less than a car without braking regeneration. But you can do much better by minimizing braking in the first place.
     
  14. Mendel Leisk

    Mendel Leisk Senior Member

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    Route choices, if available, can help mpg:

    We've got a couple of ways to head downtown. One is via the freeway, speed limit 90 kmh (and everybody hassles you to speed), or a secondary coastal highway, speed limit 80 kmh. Haven't taken the freeway in over a decade. Easier on the nerves too.

    There's a couple of ways to get to one of our semi-regular destinations. One's more direct, but is up-and-over a big hill. The other's a bit longer, but goes around it. I'm not sure how that would work out, in our case, and I usually go the up-and-over route, prefer it for the road vibe, but yeah, something to think about.

    The name of the game ultimately, is to use less fuel. A lot of people turn it into a mpg game, and will actually drive further, to improve mpg, but that seems nonsensical. Simplest way to reduce fuel use, is to just drive less. Walk to local destinations, reduce your reliance on restaurants, Starbucks for coffee, that sort of thing.
     
    #14 Mendel Leisk, Sep 1, 2019
    Last edited: Sep 1, 2019
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  15. Prodigyplace

    Prodigyplace Senior Member

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    The Prius, unlike non-Hybrid cars has better economy in city driving. The 2017 is rated for 54 mpg in city but only 50 mpg for highway driving.
     
  16. Aaron Vitolins

    Aaron Vitolins Senior Member

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    Lisa I'm so jealous! I have a Ford c-max hybird and I can barely get 40 MPG on the highway!
     
  17. sam spade 2

    sam spade 2 Senior Member

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    Indeed.

    But IF you are taking the displayed number as gospel, you might be fooling yourself.
    Starting a trip high up in elevation can contribute to good mileage too if your destination is near sea level.
    So can a sustained tail wind.
     
  18. sam spade 2

    sam spade 2 Senior Member

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    That is not a "rating", it is an ESTIMATE.
     
  19. Mendel Leisk

    Mendel Leisk Senior Member

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    It is so convenient to quote and rely on displayed mpg, and Toyota bare-faced BS's on it, around 7.5% (in my 3rd gen experience).
     
  20. RRxing

    RRxing Senior Member

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    For my 2017, the Displayed/Calculated variance ranges from 3-6%, and not in Toyota's favor... ;)