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Extra Auxiliary Heater in Prius for climate demand?

Discussion in 'Gen 3 Prius Technical Discussion' started by dig4dirt, Jan 10, 2020.

  1. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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  2. dig4dirt

    dig4dirt MoonGlow

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    Yep that is it!

    I would not want to have to change that puppy out.
     
  3. dig4dirt

    dig4dirt MoonGlow

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  4. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I saw it in an ebay ad for another part, then tried to read the microscopic print with old eyes. The part number took me to 2017, but I doubt it changed.
     
  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    This any good?
     
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  6. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Yours is cheaper than mine!
     
  7. dig4dirt

    dig4dirt MoonGlow

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    Yep same one discounted!
     
  8. Ronald Doles

    Ronald Doles Active Member

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    I couldn't find any technical specs for what is called the "Quick heater".
    It provides some instant heat to the heater/defroster air stream after a cold start in cold climates.

    There may be more conditions than the ones that I have listed but as near as I can tell, it operates on the following logic:

    Heater disabled above 50 deg F ambient or in ECO mode or the blower is not on.

    Heater enabled below 50 deg F ambient, while not in ECO mode, with the blower on and coolant temperature of less than 150 deg F.
     
    #28 Ronald Doles, Jan 12, 2020
    Last edited: Jan 12, 2020
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  9. Ronald Doles

    Ronald Doles Active Member

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    The funny thing about aftermarket sales of this electric heater is, how many would they sell? It's functionality is so slight that people would have no way of knowing that it failed. Actually most people don't know that it even exists.

    I didn't know until I did some serious digging and since my Prius is always in ECO it would never be energized on our car anyway.
     
    #29 Ronald Doles, Jan 13, 2020
    Last edited: Jan 13, 2020
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  10. dig4dirt

    dig4dirt MoonGlow

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    Yeah, I actually think it seems strange to possibly not work in "eco" mode.
    I would think it would be a bit more eco to use it, then to have engine run a bit more to satisfy heat demand.
    But maybe im not thinking correctly?

    I suppose either way, it does not provide enough for actual heat, but maybe for defrosting a
    windshield would be best use.

    For the Prius "c" or even Corolla, I wonder if it is standard on all models (it says it fits all models)
    or if it is actually on only the higher trims.

    Since the "c" was the cheapest Prius, seems they could have made it even cheaper,
    and only sold the lower trims in the south or non freezing climates.
    But I guess $500 or so is not a head turner in a sticker price for the most part.

    I guess it is what it is
     
  11. tonynap

    tonynap Member

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    Capitalism is so out of control it requires [checks notes] wearing only one layer of clothing year-round.
     
  12. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    I'd venture a guess that it is most economical to take heat from the gas engine only and put up with a few temperature swings that are normally handled by the electric element. Energy used by that element has to go from the fuel tank to the engine to the HSD to be made into electricity to pass through the DC/DC converter before it gets to that heater. That is a long and inefficient trip. The less energy you put through there, the better. The heat from the engine coolant is free; it is a waste product of all the work you are paying for. It just isn't available full-time due to the hybrid run pattern.

    So really your choices are high efficiency heater that runs when it runs [eco mode] or part-time high efficiency heater + rest-the-time low efficiency heater [default; non-eco mode]
     
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  13. dig4dirt

    dig4dirt MoonGlow

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    SO true when the warm up stages are already being performed.

    Gen4 fires up ICE even in EV mode when outside temp is under certain temp. (14F, i think)
    (one reason why have not upgraded our Gen3 to Gen4)
     
  14. ChapmanF

    ChapmanF Senior Member

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    I don't get the impression that it was added so much to routinely fill in during temperature swings in stop-start operation (though maybe it does, if the coolant temperature drops below its threshold), but just to get you a little more quick heat off the bat when you get into the cold car. And no, 700 watts really isn't enough to feel (it's what, half of a typical blow dryer? but blowing out several vents instead of a nozzle straight at your head), but does have a noticeable effect on the windshield; I'll turn ECO mode off for that when needed.
     
  15. Ronald Doles

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    With the Gen 3's, we have another heat source. The heat from the exhaust gasses that pass through the EGR cooler heats the coolant when the ICE is running. The cooler may be capable of transferring more heat than the "Quick heater" but the spec for btu's the cooler is capable of transferring to the coolant is not stated.

    The logic for the typical EGR solenoid is closed at idle and open when the throttle is not at idle. There may be more conditions with the Prius.
     
    #35 Ronald Doles, Jan 14, 2020
    Last edited: Jan 14, 2020
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  16. ChapmanF

    ChapmanF Senior Member

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    Not just the EGR cooler; IIRC there's a second Gen 3 exhaust-to-coolant heat exchanger further down the exhaust pipe (which is where those extra hoses go).

    The EGR cooler is primarily there to keep the recirculated gases cool, while the lower heat exchanger there is primarily to warm up cold coolant faster.
     
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  17. Ronald Doles

    Ronald Doles Active Member

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    Correction on how EGR works. The EGR valve is shut off when the engine is cold, at idle or at full throttle. That precludes the EGR helping during warm-up.
     
  18. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Technically that is the EGR helping warm things up. More EGR = less power & associated waste heat.
     
  19. ChapmanF

    ChapmanF Senior Member

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    And today's Hairsplitting Award goes to....