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Cruise Control on Highway for best MPG

Discussion in 'Gen 3 Prius Fuel Economy' started by Roger T, May 10, 2014.

  1. Roger T

    Roger T Member

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    Hi Everyone,

    I am typically driving at 60 mph on highway.

    Today afternoon I tried cruise control. It surprised me that the bar on HSI has been reduced so much with cruise control ON compared to cruise control OFF(i.e. manual control of gas pedal, i found myself giving unnecessary accelerations occasionally). The Cruise Control seems to provide minimal traction for the car to run on certain speed. With cruise control on today, my 30 miles trip achieved 54 computer mpg, with AC on, which is better than my past experience.

    To maintain a certain speed on highway WITHOUT CRUISE CONTROL, I have to adjust the gas pedal to the road condition (mostly slight terrain, without much traffic). Sometimes I give slightly too much gas which makes the car accelerate, then i response by reducing the gas pedal. The whole process of unnecessary acceleration and deceleration contributes to the loss of MPG. For the same reason, Cruise Control helps a lot on higher MPG in my situation.

    What do you guys think? Do you use cruise control often on highway GIVEN good road condition?
     
  2. Roland1555

    Roland1555 Senior Member

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    Might have changed between 2010 and 2014 models, but I'd be surprised if Toyota engineers would do that.

    My 2010 will hold speed even when travelling in the mountains here. Better than any other car I've owned in fact. Going up and downhill. Don't think it would be the case that my car with adaptive cruise would be so different from one without radar.

    I do use cruise very often, again more so these years with the adaptive feature working so well even in more dense traffic that I'd typically use in past years.

    Talk to your dealer if you find it isn't cutting it on gentle slopes, I believe it should.

    Roland
     
  3. ForestBeekeeper

    ForestBeekeeper Active Member

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    Pulse-and-glide is hated by other motorists.
    Cruise-control is loved by other motorists.

    I use cruise-control extensively and it helps a lot. We get very good mileage.

    The interstate here is posted at 75mph, I generally set cruise-control at 81.
     
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  4. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    The flatter your terrain, the more Cruise Control helps, the more vertical your terrain, the more Cruise Control hurts.

    In my neighborhood, I can drive 156 miles and only gain 90 feet, so Cruise Control works fine for me.
     
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  5. -1-

    -1- Don

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    :)I'm a big cruise control fan and use it when possible. The Dynamic Radar Cruise Control gives me even more incentive. Why not. I've had several incidents when in EV mode on the interstate, not using cruise control where my speed creeped above 62 mph and the ICE cut on. The cruise control is very accurate and there's no reason for me not to use it where possible.
     
  6. El Dobro

    El Dobro A Member

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    I wouldn't own a car without CC. I use it as much as possible, especially in cop zones. ;)
     
  7. fuzzy1

    fuzzy1 Senior Member

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    Do you use ECO mode? If not, you may benefit from trying it when not in cruise control. I use it full time, but not everyone likes it or benefits from it.

    As for cruise control, its usefulness varies considerably with both road conditions and driver style. Cruise will produce better MPG for something more than half of drivers, and works best on flatter roads. I use is sparingly, partly because I can do better, and also because I drive in a lot in places where doesn't do well or is outright dangerous.
     
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  8. Roger T

    Roger T Member

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    Sorry about the ambiguity of my post. The Cruise Control on my prius behaves exactly the same as yours (hold speed even in uneven terrain). The reason i think it saves gas is because it saves me from some unnecessary acceleration.
     
  9. Roger T

    Roger T Member

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    Yes, I do use ECO mode, almost exclusively. It reduced the chance of excessive acceleration for me. :)

    The bold sentence above is exactly my situation. As a relatively new driver with a lead foot ;) , I tend to push on the gas pedal unnecessarily, even on highway. So the cruise control saves me a lot.
     
  10. dorunron

    dorunron Senior Member

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    Roger,

    Have you tried "Regular" Mode? Regular Mode is all buttons off... If you are like me, you will find that Regular mode is basically in between ECO and Power. Gives ample power without having to move the go pedal a considerable distance, but is still easy to operate the pedal when doing pulse and glide.

    I prefer that for normal driving, but if I am on the highway I put it on ECO mode. It has been said the "A/C runs more efficiently" on the highway when driving in ECO mode. I usually switch over to ECO mode once I have the cruise set. When I come off the highway, I go back to Regular mode. I only use Power mode if I am in heavy traffic with a lot of traffic lights and high speed limits. That way I keep up with the pack, and not break the flow of the traffic. I just remember that in Power mode, a little bit of pedal makes a BIG difference.

    The modes are simply how the go pedal is fine tuned for response of the ICE. ECO takes more pedal travel to achieve the same thing in Regular mode. Regular mode takes more pedal to achieve the same thing in Power mode. Power mode has the least amount of travel/movement of the go pedal whereas ECO mode is just the opposite.

    Ron (dorunron)
     
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  11. Emcguy

    Emcguy Member

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    In the v cruise control is pretty much the only way to get the car into 'stealth warp'. We have a freeway hill where the MG is used to hold the car in 'neutral' at 70mph for quite a while. In hilly areas I've found it works to hard uphill and over regens downhill, but hey, if I'm on holiday, then cruise it is.
     
  12. cproaudio

    cproaudio Speedlock Overrider

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    I love radar cruise control but I hate the mileage. It gets worse than without. It doesn't anticipate up hill or down hill so you're left with flooring or regen when coming to overpass and underpass. You can pulse and glide between 60 and 70 mph and get better mileage than CC at 65MPH. The only time I use DRCC is when I'm drafting behind a big rig. Don't get your panties in a bunch because with DRCC at 3 bars the following distance is about 3-4 seconds. Enough distance for 4 cars to cut in front of me.
     
  13. Roger T

    Roger T Member

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    Hello Ron,

    I have never tried the Normal mode on Highway yet. I will see whether it gives me better pedal control... Thanks for your advice.
     
  14. ItsNotAboutTheMoney

    ItsNotAboutTheMoney EditProfOptInfoCustomUser Title

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    Cruise control is relatively good at maintaining constant speed. But it's the need to maintain constant speed that hurts fuel economy.

    If traffic is light enough that people can pass easily, then you can allow your speed to vary. But traffic tends to bunch, so be aware of traffic approaching from behind to know when you'd be holding somebody up.

    ACC may be nice, but beware of tailgaters.
     
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    I use cc frequently, and yes it helps improve mpg, at least for me. Keeping an eye on the instant mpg on my Scangauge, it seems very quick to react to changing load conditions, delivers consistently good mpg values.
     
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  16. fuzzy1

    fuzzy1 Senior Member

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    ECO won't directly make A/C more efficient, it just lets the climate control dial back the amount somewhat.

    ECO also allows more slop in the cruise control's speed accuracy, which should somewhat reduce the wastage caused by trying to maintain a precise speed in variable conditions.
     
  17. jhinsc

    jhinsc Senior Member

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    I use CC to avoid speeding tickets, first and foremost, and then to maintain a steady speed, which make for a more enjoyable drive. On generally flat terrain I think it helps with gas mileage but on drives with hills, it results in lower mileage for me. I also stopped using ECO, especially during warm days - staying cool and having a more responsive gas pedal is more important to me.
     
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  18. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I use cruise control at all speeds above 24 mph, city and highway. You can make small speed adjustments patting the stalk up or down for a 1 mph change to a 'stack' limit of ~3 back-to-back changes. To coast or slow down, I shift into "N" knowing I'll have to set the cruise control when I shift into "D".

    Bob Wilson
     
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  19. bwilson4web

    bwilson4web BMW i3 and Model 3

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    It was one of the critical omissions in the 2001 Prius that kept us from buying one. It also had an in-car GPS and a hideous green color. But cruise control was critical for us. Instead, we bought a 2001 Echo with: dealer installed, after-market cruise control; electric door locks, and; silver. We sold it in 2009 to help pay for a 2010, silver Prius with stock cruise control and no in-car GPS . . . we use Garmin.

    Bob Wilson
     
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  20. jdk2

    jdk2 Active Member

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    I have not seen that behavior at all ECO has no effect on the amount of acceleration the CC demands. When ascending a hill, the engine will go to WOT very quickly.
     
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