Help for a new Prius owner

Discussion in 'Gen 2 Prius Fuel Economy' started by LongRun, Dec 12, 2006.

  1. LongRun

    LongRun New Member

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    Is the pulse and glide more difficult to do, that is turning off the display arrows, when the battery charge is a little low?

    And when you're pulsing I've found out that when I go from gliding, all arrows off or regen, to power, if only the electric motor is helping, that I get better mileage by getting the ICE to come on too, is that what others have found?
     
  2. kDB

    kDB New Member

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    http://hybridcars.about.com/od/ownership/a/pulseandglide.htm

    In most cases it's best to glide with no arrows, and pulse with arrows from ICE to wheels, and ICE to MG to battery (first image). Though you could pulse with two other scenarios (image 2 and 3)
    [​IMG][​IMG][​IMG]
    Images borrowed from http://john1701a.com/. A lot of good info there.

    And yes it is a little harder when the charge isn't where the car likes to keep it, 6 bars. After you drive the car for a while it gets a lot easier to glide, for you anyway.
     
  3. LongRun

    LongRun New Member

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    <div class='quotetop'>QUOTE(kDB @ Dec 12 2006, 01:12 PM) [snapback]361118[/snapback]</div>

    Thanks for the link and the info. On a 75 mile commute I'm now doing 67mpg one way and 63mpg the other way. I makes the drive a little more interesting and there are fewer traffic jams when you just go with the flow of traffic. Once you try to speed up, you hit it and that makes commuting a pain.
     
  4. eagle33199

    eagle33199 Platinum Member

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    grrrr.... complaining that high mileage isn't high enough... try coming up here where it's nice and cold :p I'd kill for your mileage right now...
     
  5. LongRun

    LongRun New Member

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    <div class='quotetop'>QUOTE(eagle33199 @ Dec 13 2006, 06:47 AM) [snapback]361436[/snapback]</div>
    Today it's 74F in Los Angles, but with the wind chill factor it's 76F. I worry about the mileage and starting the Prius with the temperature dips into the 50's, and believe me it's happened several times this winter. Because of the cold weather I run synthetic oil. You can't be too careful when the weather turns cold.
     
  6. theorist

    theorist Member

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    <div class='quotetop'>QUOTE(kDB @ Dec 12 2006, 04:12 PM) [snapback]361118[/snapback]</div>
    I try to both pulse and glide without arrows going to or from the library. Perhaps I misread, but this was my understanding of what the hypermilers who have attained remarkably low fuel consumption did. They call this staying out of the battery. Did anyone hope to save gas by charging the battery but not drawing from it?

    As for the pictures, doesn't the battery discharge and feed energy to the motor when truly high power is demanded when accelerating hard? I guess the 'high power' diagram above represents high engine power as opposed to high hybrid system net power or acceleration, which will have an arrow going from the battery to the motor?

    As for the SOC (state of charge), the hybrid system will try to return a battery's state of charge to around six bars. Pulsing while staying out of the battery when the SOC is lower than 6 entails (requires and enables) shorter, more intense pulses. I forget what SOC some of the hypermilers reported while pulsing and gliding their way to over 100 mpg.
     
  7. kDB

    kDB New Member

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    <div class='quotetop'>QUOTE(theorist @ Dec 13 2006, 06:32 PM) [snapback]361934[/snapback]</div>
    The problem with that is you are constantly drawing forn the battery. Headlight, Radio, etc. If you constantly deadband, your SOC will eventually fall.
     
  8. theorist

    theorist Member

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    Here's a link to a hypermiler website where hypermilers in the US and Japan report intentionally running the SOC down to a maximum of 4 bars to sustain over 100mpg.

    http://www.cleanmpg.com/forums/showthread.php?t=1793

    Wayne Gerdes reports getting his best mileage after forcing the battery down to a maximum of 4 bars. TeddyGirl in Japan reports keeping her battery at 3 or 4 bars.

    TeddyGirl also reports:
    Her basic is no arrow gliding, but she sometimes uses weak battery powers when she needs to maintain speed.
    She does not care about the "deadband" pulse and she sees green charging arrow, but she does not do too much to see yellow discharge arrow.

    No arrow gliding ... sees green charging arrow ...? Perhaps she tries to allow for minimal charging to power the 12 volt load as kDB suggested, but minimal charging indeed to hold the battery down to 3 or 4 bars.
     
  9. nerfer

    nerfer A young senior member

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    <div class='quotetop'>QUOTE(LongRun @ Dec 13 2006, 05:16 PM) [snapback]361901[/snapback]</div>
    Are you being serious? I think you forgot the smiley face. The weather isn't cold until it's below freezing. It's not bitter cold until it's below zero (fahrenheit, or about -18'C). When it's -40' (C or F, it's the same) then you know you're alive when you walk outside, better than a strong cup of coffee. And we're not talking wind chills.
     
  10. LongRun

    LongRun New Member

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    <div class='quotetop'>QUOTE(nerfer @ Dec 14 2006, 12:45 PM) [snapback]362400[/snapback]</div>

    Gotcha. :blink: :blink: :blink: :blink: :blink:
     
  11. Pinto Girl

    Pinto Girl New Member

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    <div class='quotetop'>QUOTE(LongRun @ Dec 13 2006, 06:16 PM) [snapback]361901[/snapback]</div>
    Teeeheeee! That's funny..."when the weather turns cold..."

    That nippy Santa Ana really cools things off, eh?
    [laughing]
     
  12. VABeachPrius

    VABeachPrius Member

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    eagle,

    I still get 65ish mpg when its 30F outside. :p You can keep your artic air right where it is. :D It's almost 70F today.


    theorist,

    When I pulse, my energy screen looks like image 1. When I glide, there are no arrows. I do not deadband pulse, because that type (very quick) of acceleration does not work for my traffic and traffic light scheme. Every time I have tried the deadband pulse, sure as heck, there is a red light 200 feet ahead. Pulsing like image 1 is slower and lets me take in what is going on ahead and behind of me. When I start my pulse from a stop, my consumption screen looks like image 2, until I hit about 20 mph. Above 20ish mph, my consumption screen looks like image 1.

    If the SOC is very low (i.e. after a very long EV; which I try not to do), the instantaneous mpg values are very low as the computer is trying to charge the hybrid battery. If the SOC is very high, (excuse my poor attempt to describe this), I notice that at the same instaneous mpg value my acceleration rate is quicker. I think more of the engine power is acutally being used to accelerate the car, rather than tying to charge the battery.

    As far as acceleration goes:

    Image 1 should be named "light acceleration"
    Image 2 is acceleration more than image 1, "Medium acceleration", but less than image 1
    Image 3 is acceleration more than image 2, "Moderate acceleration", but less than image 2
    Image 4 (not shown) would be like image 2, but the arrow would be going from the battery to the electric motor. That would be the highest form of acceleration, "High Power Acceleration"
     
  13. Pinto Girl

    Pinto Girl New Member

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    Sometimes I find myself wondering if the pulse and glide is actually faking out the computer, more than really mileage...?

    Note: The best I've gotten on a tank is 58.something, and I'm more of a corner-carver, so consider the source.

    Does the mpg achieved with pulse and glide add up to the actual amount of fuel burned?
     
  14. eagle33199

    eagle33199 Platinum Member

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    <div class='quotetop'>QUOTE(Pinto Girl @ Dec 15 2006, 01:23 PM) [snapback]362877[/snapback]</div>
    Yes, Pinto, it does. You can do the experiments your self: drive for a year using P&G, and you'll see the MFD mileage closely matches the calculated mileage (from gas put into the car and miles driven) If you then drive "normally" for a year, without doing any pulse and glide, you'll see the same close correlation between MFD and calculated - most likely very similar difference between the two numbers, as well.
     
  15. MSantos

    MSantos EcoAccelerometry

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