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Uphill technique -- am I just imagining it?

Discussion in 'Gen 2 Prius Fuel Economy' started by jimgraffam, Nov 14, 2005.

  1. jimgraffam

    jimgraffam New Member

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    Hi. Lots of hills out my way and today was my first day commuting w/ my new Prius so I was trying some things. One thing I noticed was that my mileage to work was better than my mileage from work. The main difference is that I used the cruise control home thru many of the hills vs. avoiding it on my way to work.

    I noticed that if I stuttered the accelerator (avoiding the term pulsing even though it may be a more appropriate term) by letting off just a bit and returning it right back, it seemed to kick in electrical assist and keep the mpg up better than cruise did.

    Am I just drunk with the newness of the Prius experience? Or, is this a technique that others have noticed as well. (or both? ;)
     
  2. Wayne

    Wayne Active Member

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    Yes, this is a common technique to shut down the motor and glide along using battery power. At higher speeds your speed will bleed off, but at lower speeds you can maintain it until you hit a hill, or the battery needs recharging.

    I usually keep the consumption screen up to monitor whether the motor is running or not. Just look at the instantaneous MPG bar, it reacts within a second or two.

    You're learning, that's great!
     
  3. efusco

    efusco Moderator Emeritus
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    Well, it's really too early to draw too many conclusions.

    The 'feathering of the pedal' that you did on the way to work is a real thing, and you can get the ICE to kick off and into all electric more easily that way. That is often beneficial to fuel economy, though not always.

    Your trip to work may be slightly more downhill than uphill and, obviously, the opposite on the way home.

    Traffic, temperture, technique, how you held your mouth may all be factors too.

    Give this several weeks and see if you can detect trends. You've many many thousands of miles of driving to hone your technique and really get an understanding of what your car is doing and what it will do under various conditions.

    It's an enjoyable and educational process...I don't wanna spoil it by telling you the ending! :rolleyes:
     
  4. jimgraffam

    jimgraffam New Member

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    Learning a lot over the past 2 months while awaiting delivery. I'll keep the feathering up uphill and pulse 'n' glide down and see how it goes. Must be doing something right so far... staying between 53 and 55 mpg on first tank... hope it lasts.

    Follow-up question: Does feathering the pedal tickle??? :D
     
  5. Jack 06

    Jack 06 New Member

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    If you've got a moderately hilly,non-high-speed (as in divided four-lane highway) road, where average speed might be 40-50, you've got an ideal "lab" for developing a few techniques. I'd avoid cruise on such a route unless you have a stretch or more of at least 3-5 miles of relatively level, constant speed.

    Other might disagree; there are cruise aficionados who maintain cruise always gives them their best MPG. But your anticipation of terrain, especially hilltops, gives you an automatic advantage over cruise.

    Have fun!
     
  6. Jack 06

    Jack 06 New Member

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    do not know--does your Prius giggle? :lol:
     
  7. sanguis

    sanguis Member

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    I've noticed that the cruise control will allow the motor regeneration breaking when going downhill. I think that is a waste and its better to just glide downhill and let your speed increase a few mph. I haven't watched the MFD specifically to see if the downhill recharges the batteries, it's just how it feels.

    If you keep the gas pedal just barely pressed down in the downhill, the engine shuts off, the car accelerates a little, and there's no automatic regeneration of the battery (again my current theory).

    I also think its better (efficiency-wise) to accelerate hard on the uphill and glide the downhill versus the other extreme of a constant (medium) load on the engine.
     
  8. jimgraffam

    jimgraffam New Member

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    Nope. Just tolerates it quietly. :lol: Guess that empirically proves that it does not tickle.
     
  9. jimgraffam

    jimgraffam New Member

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    Wouldn't any electrical assist help overall efficiency vs. a hard nearly 100% ICE uphill? I tend to see a temporary boost in mpg when the ICE is assisted.
     
  10. hdrygas

    hdrygas New Member

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    The electricity ultimately comes from gas and as you transform one type of energy into another there are losses at each step. The regenerative breaking is better than friction breaking converting inertia to heat but it still all comes from gas so using the motor less is better. Learn to step on the gas so there is no transfer to or from the battery when you can.
     
  11. Bionic

    Bionic New Member

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    I also recently received my Prius and am "struggling" with learning the driving technique (it's not much of a struggle in a car this great). So far I feel like I'm missing something, seeing as how my MPG is in the low 40s. I have quite a few hills between home and work, so I'll give the "pulse" technique a try today.
     
  12. LaughingMan

    LaughingMan Active Member

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    How far do you live from work? How long is your commute, that is?

    The shorter the daily commute, the worse it is for your mileage.
     
  13. jimgraffam

    jimgraffam New Member

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    Thanks, hdrygas. That makes sense downhill and level, but I'm actually considering the case where I am going uphill. Are you saying that one can stealth thru parts of an incline and gain efficiencies?

    Anyways, I tried feathering on the way in to work again today and was able to keep the mpg up in the 30s going up most of the hills (some big hills excepted) (Rt 2 to Rt. 495 for you MA folks.) Seems like the best advice on this and most other threads is to keep it up for a while, try some things, tune, retune, and keep reading.
     
  14. Bionic

    Bionic New Member

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    Yeah, I'm thinking that might be it. My commute is about 5 miles, all on surface streets with a good number of stop lights/signs

    If it wasn't for my bad knees (and oncoming winter), I'd probably be biking it more.

    I guess I need to start taking the long way to work if I want to get my mpg up :rolleyes:
     
  15. aaf709

    aaf709 Ravenpaw of ThunderClan

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    If you have SKS, take a hose and try spraying water on the side by the driver's door. If you have your fob with you it should lock and unlock like the car's ticklish. :D
     
  16. LaughingMan

    LaughingMan Active Member

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    That's about the same as my commute. You will get better at it. I was able to pull my averages from about 40 when I first got my car, and now I average about 50 with the same commute... and I go places over the weekend, which helps my mileage immensely.