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Optimum MPG-Way To Drive The Prius?

Discussion in 'Gen II Prius Technical Discussion' started by Susan4ET, May 9, 2007.

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  1. Susan4ET

    Susan4ET Oldie but Newbie!

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    If maximizing miles per gallon is always the goal are there any Prius driving instructions that explain the best way or the best speed to drive the car under different conditions. I assume at this point that I can experiment and learn over time what all works best from the power-train feedback but I would like to know some of this up front too so I can know that my Prius is working properly...or not.

    For instance... If I'm driving over a mountain pass and the speed limit and conditions are not exceeded or a factor would it be best to drive at 65 mph or 55 mph? Other situations like straight and level driving speeds?

    Does that battery in the touch-screen display ever show a fully charged state (full of bars all the way to the top)? Most of the time they seem to show 3 or 4 bars to mid-range. When it shows 2 bars the blue turns to purple. If on a long trip will they fill all the way up and turn a green color? Is there an article anywhere that describes all this?

    I haven't figured out nor am I clear on how to figure it out how to approach 60 mpg in the city or 51 mpg on the highway. I know that these are extremes the EPA has come up with that can't really be reached but I need to learn what I need to do to know how best to approach the highest mpg possible. If it always ends up to be just driving the car as slow as you can then that will pretty much mean staying at or under speed limits. If I'm on a highway posted 70 max am I really going to drive it at 55? I don't think so... I like to drive 5 mph over the speed limits but maybe that won't feel comfortable in the Prius?

    Well, you get the idea what I'm looking for I think. Thank you.
  2. bestmapman

    bestmapman 2010 Prius

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    Hello,

    First technique to learn is Pulse and Glide

    There is a lot of good information in this forum. I am new also, but have gained a lot of very good techniques
    in this forum. The first thing I learned was Pulse and Glide. Basically this is moderate acceleration (Pulse) followed by (Glide) essentually coasting using the go-pedal (accelerator) to get into the different modes. Search for Pulse and Glide or P & G and you should come up with some good threads.

    Also you should read some of the sticky threads in the Fuel Ecomony forum this would be a good one to start with:

    Sticky: New owner? Want MPG help? Read this first. great info from one of our own

    One fact that I learned is that the Prius has essentually two different operating regions.

    1) Below 42 MPH: In this region the gas engine(ICE) will stop running in the glide mode and will come on as power is needed. Using P & G you can use this to great advantage.

    2) 42 MPH and above: In this region, the ICE always is tuning. It does this so MG2 (the small motor/generator) does not overspeed. This presents a whole different set of techniques to maximise fuel ecomony. Search for Warp Stealth. Hope this is a good start.

    The other good thing about this forum is that there is no shortage of knowlege or humility. So you should get plenty of responses.
  3. JimboK

    JimboK One owner, low mileage

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    Hello, Susan. Welcome to PriusChat!

    Bestmapman's suggestion for a starting point is on target. To save you some time, here's a link to that thread. (Actually, a minor correction: MG1 is the smaller of the two motor/generators.)

    Also read this article on CleanMPG.

    The battery shows a fully charged state very infrequently. (In reality, when it's showing fully charged it's still only about 80%, but to keep it simple here we'll call it "full.") The Prius' computer does an excellent job of battery management to maintain longevity -- it prevents it from being either overcharged or discharged. The optimal state is 6 blue bars. When it starts to creep higher, the system pulls a little off to help power the car. As it gets lower, the engine runs a little more to help charge it up. Generally the only time you'll see it "full" is descending a long downgrade, e.g., a mountain road.

    Like bestmapman says, there's a lot of knowledge here, so stick with it and keep searching. I'm not sure I agree with him about the humility part, though. :D
  4. FireEngineer

    FireEngineer Active Member

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    If your driving environs are more urban than suburban/country learn to glide, forget the pulse.

    Wayne
  5. bestmapman

    bestmapman 2010 Prius

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    <div class='quotetop'>QUOTE(JimboK @ May 9 2007, 07:30 AM) [snapback]438155[/snapback]</div>

    "The other good thing about this forum is that there is no shortage of knowlege or humility. So you should get plenty of responses."

    I guess "shyness" would be the better work. I just meant that people here won't hold back there opinions. Meant as a good thing for a forum environment.
  6. seftonde

    seftonde New Member

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    Hello Susan,

    The other posters are right - check out threads on pulse and glide and the link that the one person mentioned.

    I am also new, I have had my Prius for 5 weeks. I drive 41 miles one way to work, 7 miles on back country roads, 30 miles on the highway and the last 4 (or more) in city stop and go traffic (Hartford CT).

    I usually set my cruise control for 74 on the higheay portion. I'm still feeling my gas mileage out of course, but I average about 45. The cruise, in my opinion, does a very good job of maintaining high efficiency travel, especially on my highway which is gently rolling up and downhill.

    My other vehicle is a pickup that gets about 13 mpg. Yesterday I turned 3000 miles on the prius. At 3 bucks a gallon I have saved over 500 dollars in the last month by driving the prius than the truck!

    Daniel
  7. brick

    brick Active Member

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    <div class='quotetop'>QUOTE(Daniel Sefton @ May 9 2007, 01:34 PM) [snapback]438359[/snapback]</div>

    Do you come up 9 or 2? Both have some pretty good hills that will sustain speed in a "warp stealth" glide if you ever feel like trying to break into the 50s. Just cancel CC at the top and feather the pedal on the way down, just enough pressure to cancel regen. You'll see arrows indicating power from the battery to the wheels, which really just keeps the ICE spinning without using any fuel. The car coasts free in this state and provides a very nice boost to your fuel economy. Unfortunately you do have to get up the hill first, which will take less fuel if you drop down closer to the 65mph limit. (Aero drag gets pretty nasty at those higher speeds, and slowing down the 9mph adds less than 4min to your commute.) That should give you an easy 10% boost in fuel economy.

    I guess that kinda contributes to answering the OP's question. ;)
  8. Susan4ET

    Susan4ET Oldie but Newbie!

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    Someone could write a technical manual on the Prius covering driving, technical specs/systems of the car and secrets.
  9. JimboK

    JimboK One owner, low mileage

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    If you haven't already seen it, visit john1701a's site. Lots of useful, well-written, and easily understood information on the car and its systems, including a newly updated user guide.

    John is a proponent of the "just drive it" philosophy, so you'll probably find less on techniques for optimum MPG there than at some of the links we gave you previously. There is certainly nothing wrong with that approach; the Prius will still out-perform virtually every other car on the road MPG-wise. Some of us are nerds and want more. :D
  10. bwilson4web

    bwilson4web 03 and 10 Prius

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    <div class='quotetop'>QUOTE(Susan4ET @ May 9 2007, 04:18 AM) [snapback]438137[/snapback]</div>

    I've been collecting data on the 2001-2003 Prius MPG vs MPH:
    [​IMG]


    On the highway, one good technique is to find slow moving traffic, say a heavy semi-trailer, and follow it at a safe distance. This is more to take advantage of lower speeds and let the other traffic flow around you and the trucker. The truck is your 'pace car.'

    As others pointed out, there is a difference between speeds below 42 mph and above. As a general rule, try to stay under or above 42 mph and avoid getting in a speed range where you are transiting between these two control laws. The transitions can cause the ICE to start or stop not based upon what is most efficient but simply because you are transiting this critical speed.

    Otherwise, pay attention to your maintenance:
    1. oil 3/4 of full
    2. tires at 42/40 or max cold pressure (if the ride is OK)
    3. reasonable oil change intervals 5-10k miles
    4. replace air filter annually
    GOOD LUCK!
    Bob Wilson
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