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Eco mode

Discussion in 'Prius c Main Forum' started by Banjo, Oct 11, 2012.

  1. Banjo

    Banjo Junior Member

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    I did an experiment, on my regulaer commute route 38 miles. I usually average about 56-62mpg, with cruise control set to 65mph. I set my cruise to 60mph and activated ECO mode.Arriving home final mpg was 53.How do ya like that!
     
  2. bisco

    bisco cookie crumbler

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    i don't think it matters to cruise what mode your in, mpg difference because of other factors. repeat 10 times each mode and get back to us.:)
     
  3. RocMills

    RocMills Active Member

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    You got lower mileage going slower and using Eco? How odd.

    I wonder... does cruise control allow for the EV to come into play automatically, or is cruise control always going to be ICE only?

    And as Bisco said, you should repeat the same experiment several times to get an average before you decide which way is better for you.
     
  4. hieronymous

    hieronymous Member

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    Your mpg 0f 53 is only a little below the lower end of your average 56-62 mpg - a decent head wind would do that.

    When you get off the freeway you might usually run your traction battery down to get the best mpg possible - with ECO mode on, your C would probably protect its energy reserve a little more conservatively by boosting it with the ICE .

    Cruise control is no more than a substitute for your foot in trying to maintain speed. At 65 the mode would make little difference to the end result; the ICE is doing most of the work.
     
  5. Corwyn

    Corwyn Energy Curmudgeon

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    Since Eco mode affects the response of the car to the gas pedal (and some AC/heat controls), and since when you are in cruise control you aren't touching the gas pedal, it seems likely that Eco mode isn't the cause of the difference in MPG.
     
  6. Tracy

    Tracy Member

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    I think cruise pulls in the electric motor for more power as needed, but cruise control is for over 40 mph so you don't have ev only. I had the sense that my car was getting better mpg going 60 (or pick a highway number) when I used cruise versus doing it myself. It just seemed to very smoothly cycle engines on and off.
     
  7. SquallLHeart

    SquallLHeart The Techie Guy

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    i rarely use cruise control because of how the car behaves during any uphill incline. the cruise control will want to maintain speed.. and will use up fuel as necessary to do that.

    the beauty of driving without cruise control is that you are able to see what's on the road ahead.. something the cruise control can't do.

    similar with ECO mode.. it's just a tool.. driven properly.. a human being can easily get better fuel economy without it. i personally don't use it unless i'm running the A/C.
     
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  8. Corwyn

    Corwyn Energy Curmudgeon

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    How? I can understand how you could get the same fuel usage in normal mode as eco mode, but how can you get better fuel economy in normal mode (assuming that you drive optimally in both modes)? Of course, it easy to get better economy in normal mode if you drive badly in eco mode.
     
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  9. Ryephile

    Ryephile The Technophile

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    You answered your own question. Furthermore, SquallLHeart was referring to the cruise control being typically less than ideal for fuel economy versus a well trained driver on hilly terrain.
     
  10. Corwyn

    Corwyn Energy Curmudgeon

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    If the only thing SquallLHeart meant was that it was possible to drive worse in eco mode than normal, then I agree, but don't see much merit in bothering to say it. If there is some way that he envisions driving well in normal mode beating eco mode driven just as well, (which is how I read that) that would be something worth knowing.
     
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  11. RocMills

    RocMills Active Member

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    I interpreted the post by Squall the same way Corwyn did - that he was stating he could get better mileage without using Eco Mode. Shrug. Not that the original wording matters as think we all know what he was trying to say. Or not. LOL
     
  12. Rob.au

    Rob.au Active Member

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    I think this needs to be clarified. Cruise can be set when your speed is above 25 mph (40 km/h). I use mine all the time at 50 km/h (31 mph) or 60 km/h (37 mph) where I find the posted limit a bit ridiculously low and too annoying to maintain manually when the car will happily do it for me.

    The cruise doesn't change the car's behaviour... it's simply a replacement for you providing input via the pedal.

    Not only will the cruise control happily run the car without the ICE, but in a significant and delightful difference from cruise control in conventional vehicles, it has access to the regen braking, so if cruising downhill it will use regen braking to maintain your set speed without you needing to provide any pedal input (and without automatically cancelling cruise by you operating the brake pedal). It's amongst the things I love most about this car.
     
  13. X HCH2

    X HCH2 Member

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    Cruise control is not the way to save gas. Especially in ECO, where the pedal sensitivity is drastically reduced to make it easier to modulate with your foot.
    In cruise, as you approach a hill, the engine will race excessively to maintain the speed. You will be much better off to lose a few mph on the way up by keeping the pedal constant or backing off a little. Cruise will floorboard it to try to maintain its set speed. This will kill your mileage. It is worse in ECO because it is so sluggish, that it will be far behind the setpoint before it starts to notice it and then it races even more.


    X
     
  14. SquallLHeart

    SquallLHeart The Techie Guy

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    yes.. the reason why ECO mode can be detrimental to your mileage are the methods it uses to slow down your acceleration.. esp. if you're doing P&G.. it's usually beneficial to get up to speed at a faster rate than what ECO mode allows you to easily... and then glide from there.

    on a similar note, those who drive a regular liftback or a V have the larger 1.8L engine that gives them plenty of power.. and thus.. have PWR mode available to those vehicles... and under good conditions and with a good driver.. more aggressive P&G techniques utilizing PWR mode can result in better fuel economy.

    cruise control.. esp. on any road conditions other than flat.. can hurt your mileage because unlike a driver with two eyes... the car can't see the road conditions ahead.. something i've already mentioned... on completely flat roads? yea.. sure. it could compete with a good driver.
     
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  15. fjpod

    fjpod Member

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    Am I the only one that thinks it is odd that the OP says he gets 56-62 mpg with CC set at 65? A little high, no? Sure, you can get this on a one way trip, but repeatedly on a round trip???
     
  16. SquallLHeart

    SquallLHeart The Techie Guy

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    it's downhill.. yanno.. both ways.. lol. :whistle:
     
  17. Rob.au

    Rob.au Active Member

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    This is not so black and white. The engine will only power up excessively on more significant uphill inclines. On moderate hills it will stay entirely within the ECO area. If the hill has a sudden crest such as if you are going straight over the top of a ridge line, then sure, cruise would fail to back off when it should. However many hills don't crest in this way and the cruise control does an excellent job of rapidly adapting to the conditions, smoothly adjusting the input probably better than any human will.

    This depends on the circumstances.

    I would recommend people try out cruise control for themselves and get used to how it behaves. There are times when not to use it for this reason, but it is easy to learn when those times are and how to correctly use the cruise control.

    For those hills that would cause this behaviour, a simple flick of the fingers will temporarily deactivate cruise control and another flick on the far side will resume the previously set speed (or choose a new speed). Depending on the hill, another technique available is to use the +/- control to bring the set speed down as you come over the hill and back up as you go down the other side, but generally it would be easier to just crest manually.

    Cruise control is not a hypermiling technique, but there are times in cruising traffic on main roads where P&G is not a realistic option for courteous drivers and most of the time it will not kill your mileage. To take my example given earlier - there are times for example where I will use cruise to hold my car down to the posted 60 km/h speed limit. I'm already the slowest car on the road when doing this - I am not going to start P&G below that speed and I choose not to exceed it. Much of the time, cruise control will handle the car no differently than I would myself.

    If you're an absolute hypermiler and want to control every fraction of pedal travel then great - but most regular drivers should not be afraid to use their cruise control and learning its strengths and weaknesses can easily lead to more enjoyable drives with little cost.

    If nothing else, if you have a long cruisy downhill that you take at a chosen speed, why not flick on the cruise and enjoy the ride as the car adaptively manages the regen down the slope?

    ECO mode makes absolutely no difference to the cruise control, it only alters how the car interprets pedal input (and alters air con behaviour).
     
  18. Corwyn

    Corwyn Energy Curmudgeon

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    Those methods being, remapping the gas pedal response? I don't consider pushing a bit more on the gas pedal to be a hardship. YMMV.

    Power mode remapping the gas pedal response, allows less movement of the gas pedal (for the first half anyway), to achieve the same acceleration, but ALL acceleration levels are possible in any of the three modes.

    [​IMG]

    It is a persistent myth that PWR mode allows more acceleration, and that ECO mode allows less, but it just isn't true.
     
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  19. Tracy

    Tracy Member

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    Rob, thanks for clarifying this! My eye must have caught the "40 kph" on that laminated cheat sheet. I used cruise control for the first time a week ago and had to pull over quickly (at 4 in the morning - no wonder my brain wasn't engaging) to check the "cheat sheet".