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MPG down/SOC Up?

Discussion in 'Gen 2 Prius Fuel Economy' started by tag, Dec 1, 2004.

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  1. Frank Hudon

    Frank Hudon Senior Member

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    thanks Ken that's what I thought
     
    #21 Frank Hudon, Dec 7, 2004
  2. bruceha_2000

    bruceha_2000 Senior Member

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    That works for me, unless my wife is in the car. She isn't as interested in max MPGs as I am. :) But I don't wait until I can't feeel them any more, just notice I'm feeling cold. ICE almost ALWAYS goes off (when the car is stopped) if I turn off auto A/C and starts if I turn it on (after the car has warmed up).
     
    #22 bruceha_2000, Dec 7, 2004
  3. hdrygas

    hdrygas New Member

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    We recently had a mini cold snap and I saw the snowflake for the best part of 3 days. I noticed that I saw more green bars in those few days than I have since I got the car in August. I also had a new experience of the car starting up while stopped at a longish light. I had the temp at 68 a heater on recirculate at the time. I was surprised. The car truly behaves differently in summer and winter and we have not had any real winter yet.
     
    #23 hdrygas, Dec 7, 2004
  4. FloridaShark

    FloridaShark Member

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    We've been having a mini heat wave here. mid 80's
    Did my first fillup today. 54.0mpg computer. 51.27mpg actual
    What an amazing car!! :mrgreen:
     
    #24 FloridaShark, Dec 7, 2004
  5. ryogajyc

    ryogajyc Active Member

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    I've seen two references now to blocking the radiator in cold weather to prevent heat loss from the engine thus increase engine efficiency. I don't have enough knowledge about controls for the water pump and radiator fan, but from my layman's point of view, it seems like it would be pretty easy to have the computer slow the water pump and radiator fan in cold weather to improve engine efficiency. Does anyone know for certain if the Prius does this or not? I'm not sure how to check this, but perhaps a more mechanically inclined person could. Perhaps that's why blocking off the radiator did not improve efficiency as you hoped. Maybe the Prius is already controlling the radiator fan.
     
    #25 ryogajyc, Dec 7, 2004
  6. bruceha_2000

    bruceha_2000 Senior Member

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    I prefer to trust the computer. There isn't a good way to know how much gas you had in the car when you got it. Also, the pumps, while regulated, aren't necessarily accurate. There are other threads that talked about this.
     
    #26 bruceha_2000, Dec 8, 2004
  7. efusco

    efusco Moderator Emeritus
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    I remembered this thread and thought I was noticing a higher average SOC on my battery in the cool temps, but until the last 48 hours we really hadn't been consistantly below 30 degrees. Also, I usually park my car in a closed garage that is passively heated from the house so the temp of the ICE is in the 40s or 50s at start up.

    But, last noc after work the temp was ~22 degrees F and the car had been parked outside for upwards of 9 hours.

    At low speeds in the city with 'normal' acceleration I noticed the expected increased duration of ICE running and warm-up and no significant change in the use/charge of the HV Batt.

    But, once I got on the highway I began to notice the things with the higher maintained SOC that you guys were talking about.

    I'm now quite convinced that the purpose of this is something other than keeping the CAT warm...which should be quite easy...and wouldn't be necessary under hard acceleration.

    I think the entire algorhythm for the ratio of ICE : HV Batt used for acceleration power changes significantly when the battery is cold. There may be some integration for outside air temp (i.e. to conserve battery power to run the electric heaters at a stop), but I'd bet the main reason is due to the lower power output available from the cold battery.

    I'd bet that once the cabin temp reaches normal operating temps, and thus the battery is relatively warmed that you'll begin to see more 'typical' use of battery and ICE. I'm purely speculating, but that's based on the observations I had last night.

    The thing that really convinced me was at 2 seperate lights; that I usually do my best to time so I don't have to stop; I was forced to stop. As soon as the light changes there are steep, albeit relatively short, uphill climbs.

    The Prius usually does great zipping up those and the high torque generally leaves all but the most agressive drivers way behind. Last noc I was pulling up those hills (ICE plenty warm after ~15 min driving) and the ICE was as loud as I'd ever heard it and there were No Arrows from the Battery!!

    None, zilch despite the clear hard powered acceration. I'd estimate cabin temp up to around 45 degrees (Max heat, AC off, Auto off, fan on low). In fact, before I crested the hill, ICE still roaring, I saw arrows To the battery and was completely shocked b/c the SOC was at 6 bars!

    This same thing may have happened last year, but I wasn't as aware of what was going on and/or wasn't as observant, but this behavior was obviously controlled by the HV ECU and it seems clear to me that it has nothing to do with warming the CAT. I see no reason, either, to think that the purpose is to increase the SOC of the battery. If that is the main purpose during level driving it seems that the algorhythm would still want to use the battery under these hard powered climbs...but it didn't. That makes me think that the battery is to cold to provide significant power for a sustained period of time.

    Note that it wasn't cold enough to see the 'turtle' icon. Sorry to get so long winded, but I suspect someone's going to want to ask about this in the future and I wanted a fairly complete description of my observations and guesses as to the reasons we experience this cold weather phenomenon.
     
    #27 efusco, Dec 15, 2004
  8. paprius4030

    paprius4030 My first Prius

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    Evan, this is basically what i was talking about in the beginning. It surprised me to see that the car was charging an almost fully charged battery and at other times the battery wasn't being used to help propel the car when you normally would think it would. I'm glad you got to see what I was talking about.
     
    #28 paprius4030, Dec 15, 2004
  9. daniel

    daniel Cat Lovers Against the Bomb

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    What Evan says above makes sense. We've had a couple of sub-zero snaps, and my car would not go into electric mode at all during my normal 10-minute commute, but on a longer drive yesterday at just a few degrees below zero F. it did finally start behaving "normally." I was even able to go into EV mode with the heater running.

    What's this about a turtle icon? Last year I was out at 20 or 30 below zero F. and I don't remember a turtle.

    It sounds to me like what the Prius needs is a plug-in heater. Not for the engine, but for the HV battery! And while we're at it, how about for the cabin as well!
     
    #29 daniel, Dec 22, 2004
  10. paprius4030

    paprius4030 My first Prius

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    turtle icon????????
     
    #30 paprius4030, Dec 22, 2004
  11. efusco

    efusco Moderator Emeritus
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    When the HV batt get's too cold to operate properly a turtle icon appears on the dash...just in case you couldn't figure out that you were under powered.
     
    #31 efusco, Dec 22, 2004
  12. paprius4030

    paprius4030 My first Prius

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    OMG you mean there's another thing WORSE than the snowflake!!!!LOL If i ever saw that I think I'd be too frozen to operate properly, never mind the battery!
     
    #32 paprius4030, Dec 22, 2004
  13. drew

    drew New Member

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    you mean the 04-05's still have a turtle light, below is my post to the classic group - a few days ago when the mercury hit 4 below, the prius "turtle light " came on when it started. after some research in the manual, this is a "don't push me, i'm cold" light similar to what your wife says when she's uncomfortable. evidently at these temps, the battery (and everything else) is cold (or hot) enough for the elves at toyota to be concerned if you hard accelerate the car. . my wife drove the 10 miles to work normally (i.e. the energy display seemed to work normally for power to and from engine and battery) with the light still on even after the engine and cabin warmed up. when she shut it off and restarted it at work, the turtle light was out.

    i'm not sure what this accomplishes for toyota or its customers, but i'd say it uneccesarily freaks us out. given we have about 5-10 below zero mornings a year, it's a nuisance.

    of course milage is now suffering from the cold down to 45 from 55 in summer.

    02 classic 55k miles 10 k and 10 months by me
     
    #33 drew, Dec 26, 2004
  14. efusco

    efusco Moderator Emeritus
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    I've never seen the turtle on my '04 and have, since making my post here, read that there is no turtle on the 2G Prius. Sorry to start a panic!
     
    #34 efusco, Dec 28, 2004
  15. plusaf

    plusaf plusaf

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    <div class='quotetop'>QUOTE(skruse\";p=\"54459)</div>
    ah, diesels have vacuum gauges? only if they have a vacuum pump...

    ???
     
    #35 plusaf, Jan 9, 2005
  16. bruceha_2000

    bruceha_2000 Senior Member

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    <div class='quotetop'>QUOTE(efusco\";p=\"60157)</div>
    That would explain why I have seen low temps (not Jayman low) at -9F, I didn't see a turtle. My car lives out in the cold, not even a shell to keep the wind off.
     
    #36 bruceha_2000, Jan 10, 2005
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