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highway driving

Discussion in 'Prius v Fuel Economy' started by syscon, Oct 17, 2012.

  1. syscon

    syscon Member

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    Location:
    Edm. Alberta
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    I don't do much highway driving but I know some of you do.
    What is the best mode to drive on a highway (flat road), is it better to pump the gas and let it go or set it on a cruise control?
     
  2. skwcrj

    skwcrj Member

    Joined:
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    Location:
    Gig Harbor, WA
    Vehicle:
    2012 Prius v wagon
    Model:
    Two
    I use the cruise control all the time along with ECO mode. I do disconnect it occasionally for a little hypermiling around hills.

    Cruise speed makes all the difference when it comes to highway mpg's (or L/100km in your case). At 60 mph, you will see around 55-60 mpg (3.9L/100km at sea level on flat roads. Of course, going faster will yield less mpg (more L/100km). It all depends on your comfort factor.
     
  3. jonb505

    jonb505 Member

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    Location:
    Vancouver, BC
    Vehicle:
    2012 Prius v wagon
    Model:
    N/A
    I do the same as skwcrj generally.
    One thing to note, just from my experience, I found what mode you are in does not make any difference on how Cruise Control behaves. If you start to climb a hill with CC on, even in ECO mode it will accelerate hard to maintain your speed. Maybe the dynamic CC is different(smarter?) but the standard CC seems to work the same as in any other car.
    I notice though it does accelerate gently to get up to speed if you are trying to get up to speed going downhill, and it will even use regen to slow the car a bit on a steeper descent if you are going too fast.
    That aside, ECO mode does make it easier to control the lead foot when cruising down the highway with CC off.
     
  4. rotwein

    rotwein Junior Member

    Joined:
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    Location:
    Traverse City, Michigan
    Vehicle:
    2012 Prius v wagon
    Model:
    Two
    I just leave it in eco and use cruise above 35 mph. On a recent trip I cruised at 73 mph and got 43 mpg. Two in the car with light luggage.
     
  5. syscon

    syscon Member

    Joined:
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    Location:
    Edm. Alberta
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    I'm getting better fuel mileage on highway than in a city! 4.5l/100km (52.2Mpg) on highway - calculated at the pump.
    Terrain: Flat
    Temp outside: -7C (19F)
    Distance: 149.7km (93mi)
    Mode: Eco, with cruse control ON
    Speed 79km/hr (49mph).

    I know some of you drive with that speed on fast roads in the city (so do I) but I was experimenting, observing the l/100km display and it was fluctuating most of the time below 4L/100km (above 58Mpg) but as we know Prius display is a bit optimistic; and my calculation is at the pump.
    I was driving at night, so traffic was low and yes, everybody was passing me. Did I get a "finger"? :) I don't know it was too dark to see buy yes, one guy use his honk. Did it bother me, not at all.

    Nevertheless, this mileage is better what I'm getting in the city.
    Another observation is that, as I increased the speed for example to 85km/hr (52Mph) the fuel consumption is going down as well, going with that speed about 300km distance I got about 5.1l/100km (46Mpg) that is calculated by computer (so optimistic).

    Another thing I've observed is that Prius keep taking the charge from the battery automatically to keep the battery charge in check (two bars bellow the top line) and computer keeps cutting the fuel to the engine when going down hill.
     
  6. jonb505

    jonb505 Member

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    Location:
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    Vehicle:
    2012 Prius v wagon
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    N/A
    Nice detailed observations.
    Maybe not as detailed as yours but here are some observations from my last tank. I wasn't particularly driving for economy this last tank(stayed in normal mode the whole time, generous use of heater). I suspect my location is close to yours syscon, as the outide temperage has averaged about -5 the past week where i've been driving, so interesting to compare results.

    filled up tonight:
    537 km on the trip computer
    6.1l/100km avg indicated
    i calculated 6.5l/100km after 35 liter fill up

    Most of my highway driving is on highway 16 west of edmonton so speed limit is 110 kph. Depending on my mood and if i've been in a hurry i say i've set cruise on 120 kph(sometimes sprinting to 140kph to pass gravel trucks) , when i wasn't in a hurry drove 100 kph. 1/3 of my commute to work involves a section of secondary highway with a speed limit of 80. I drive the speed limit on that portion of highway. So a real mix of cruising speeds on the highway but i try to stay out of the pwr zone if theres nobody behind me and try to maximize regen when coming to a stop, no abrupt changes of speed. I would say 20% of that tank was city driving.


    Seems like cruising speed makes a big difference, so i'm going to try to keep my average speed down this next tank, keep it in eco mode. Have also started plugging in the block heater every night now if it gets below 0(set on timer to heat for 2 hours before i leave for work), neighbors might think i'm nuts, if anyone asks i just tell em i need to plug it in because it's an electric car. :D
     
  7. syscon

    syscon Member

    Joined:
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    Location:
    Edm. Alberta
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    I'm from Edmonton as well. I drove to Calgary passed weekend so I took the opportunity to take some notes.
    As you have observed speed is everything. Set the console to show "l/100km" on your display, set on cruise control and observer how the speed effects the fuel consumption. You can control increase/decrease speed with cruise control.

    2hr advance plug-in is unnecessary. After about 40min your engine temp will be reading about 30C
    I know because I have an extra gauge connected to OBDII port so it keep showing me coolant temp. battery voltage etc.
    When I took those reading at speed 79km/hr the computer was showing average fuel consumption 4.2L/100km. and I've noticed that the computer tries to keep the coolant temp. at 88C.

    As the outside temp. will be going down it is a good idea to block at least the lower front vent, 1/2in pipe isolation works best. In your case I think you commute to Spruce Grove, I would keep the upper vent open for cooling.
    I blocked both upper and lower vents as I'm making mostly short trips 16km max in a city.

    Driving in a city I make usually 800 - 850km per tank (about 40L), @500km the fuel level is usually in the middle.
    If you decrease the speed to 80km/hr (decent highway speed) no need to pass every truck :) you can expect to make about 890km from one tank.