Cold Weather, Short Trip trick

Discussion in 'Gen 2 Prius Fuel Economy' started by donee, Jan 20, 2007.

  1. donee

    donee New Member

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    Hi All,

    I think I have found a short trip in cold weather trick. When you come to a stop light within about 5 minutes of starting, the engine will idle, and there will be no indication of charging. So, apparently its just running the engine to warm it up. A bit wasteful. I put the car in park today twice after a cold soak startup while waiting at a light, and the car began to show battery charging while the engine continued to run. After about 30 seconds to a minute the engine then shut down. I had allot more battery available to bleed off in the around-town driving, and that kept the engine off later on in the short trip cycle.

    Can somebody with instrumentation check to see if this is a display glitch, or if the car actually does begin charging as described?
     
  2. Allannde

    Allannde Just a Senior

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    <div class='quotetop'>QUOTE(donee @ Jan 20 2007, 08:51 PM) [snapback]378531[/snapback]</div>
    If you get rear ended at a stop light, even gently, and you are in Park, the parking pall will break. That is not cheap to fix. I wouldn't put my car in Park at a stoplight.

    If you want to charge the HV battery or are trying to hasten the warming of the ICE, turn on the defroster and the ICE will keep running when you stop. Your mileage will suffer a little, but that is a tradeoff you may accept for the benefit you seek.
     
  3. donee

    donee New Member

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    Hi Allande,

    Good point, but then I have the cost of parking pall covered by paying insurance.

    No, the engine is running, wether I am in park or not. Its automatic. I am not causing it to run by any of my actions. The CAR is trying to warm up the ICE, I have no say in it. A 1000 RPM idling engine is just wasting gas. Pulling that energy into the battery is going to improve milleage. The engine will run for the whole stop light otherwise. Putting the car in park, appears to charge the battery, and shuts the engine down quicker.




    Hi Allande,

    Based on your comments, it does not seem that you have driven the Prius after an overnight cold soak. I had Defrost and Heater set off while trying this. It was sunny out, and the cabin temp was in the 40's F, and there was not fogging on the windows. Outdoor temp was in the low 20's F. Overnight temps were in the teens.
     
  4. Tideland Prius

    Tideland Prius Moderator of the North
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    <div class='quotetop'>QUOTE(donee @ Jan 21 2007, 09:01 AM) [snapback]378665[/snapback]</div>
    I think I know what you mean.
    Just note that if the engine is charing the battery, it's running at a slightly higher rpm. You can hear the engine pitch increase a bit when it's charging.

    Another alternative to the Park option is to quickly release and reapply the brake. Do it fast enough so your car barely moves. That'll also make the engine charge the battery if it wasn't before.


    Also, I just assumed that donee puts it in P AFTER cars start piling up behind.
     
  5. Allannde

    Allannde Just a Senior

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    <div class='quotetop'>QUOTE(donee @ Jan 21 2007, 09:01 AM) [snapback]378665[/snapback]</div>
    Hi donee

    I guess you are correct. I am into my second winter with my Prius, but I have always had and used a block heater with it and this year I have a total radiator block as well. In addition the car is always garaged which is out of the wind and a few degrees warmer because of the heat from the block heaters (two cars). I feel that keeping the mechanics of the car warm and happy will pay back many times the investment in performance as well as longevity of the car.

    I wasn't aware that extreme cold over rides the usual ICE off at stops. Defrost ON is just a trick to keep the ICE running. You didn't report a fogging problem.
     
  6. JimN

    JimN Let the games begin!

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    donee,

    Are you running with a blocked grill? If not, buy some pipe insulation and you'll find the engine acts as it does in warmer weather.
     
  7. donee

    donee New Member

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    <div class='quotetop'>QUOTE(JimN @ Jan 21 2007, 09:47 PM) [snapback]378808[/snapback]</div>
    Hi JimN,

    Yepper. But I do park outside. So, the cold soak does its thing. I have the top radiator opening all closed off, ala Efusco, and the bottom is 3/4's blocked off with my own method (3/4 inch insulation snapped into the grill work - its adjustable that way).
     
  8. LanceinOregon

    LanceinOregon New Member

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    <div class='quotetop'>QUOTE(Allannde @ Jan 20 2007, 09:28 PM) [snapback]378558[/snapback]</div>
    But what about AVOIDING accidents??? If you see a car coming at you, you will litterally be a sitting duck, if you are stuck there in PARK.

    PARK should not be used while in traffic. It is just too much of a safety risk.

    Which is more valuable to you? Having your Prius save you a little money, or saving your life??

    Lance
     
  9. donee

    donee New Member

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    <div class='quotetop'>QUOTE(LanceinOregon @ Jan 22 2007, 08:08 PM) [snapback]379200[/snapback]</div>
    Hi Lance,

    Its not that bad in the Prius, as it can shift to drive very fast. Its not like you have to be careful to avoid pulling the lever through drive. Just flick your wrist, and floor it. It takes less time to put the Prius in drive, then to get a manual transmission car in 1 st and pop the clutch, from neutral (unless the driver is riding the clutch). And its not like the stop lights in one's neighborhood are not familar to one either.

    I will be checking if Neutral provides the same benefit, but since Saturday, the car has not been cold soaked cold enough for the engine to run at a stop light. Its shutting off in about 10 seconds after stopping. It was only down to the mid 20's overnight.
     
  10. poodlemaster

    poodlemaster New Member

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    <div class='quotetop'>QUOTE(LanceinOregon @ Jan 22 2007, 06:08 PM) [snapback]379200[/snapback]</div>
    you gotta be kidding me. safety risk?
     
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