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Why 136 HP?

Discussion in 'Gen 3 Prius Technical Discussion' started by Abarnabe, Feb 17, 2023.

  1. Abarnabe

    Abarnabe Member

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    Why does Toyota declare 136 hp maximum power for the 2010 Prius when the ICE max power is 98 HP and the maximum DCL discharge current limit of the inverter is 21KW = 28hp?

    According to above statement the total max power should be 98hp +28hp = 126HP
     
    #1 Abarnabe, Feb 17, 2023
  2. Tombukt2

    Tombukt2 Senior Member

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    because you're missing something I'm sure but I'm not worth a crap enough to tell you what step you're missing but it's all good. The generation 3 has that sun gear and that goes around or is it the planetary gear that goes around the transmissions gear assembly that may add to that whatever gives you that high torque multiplication that the guys talking about the videos down and wherever he is Florida I think The Prius school guy You have to take all of this stuff and do account that's why I really don't get into it that much because it's a lot of mathematics and sitting at a desk and head scratching or whatever it is you doing a desk. I'm generally behind the wheel of the car going on service calls.
     
    #2 Tombukt2, Feb 17, 2023
  3. ChapmanF

    ChapmanF Senior Member

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    Your question might contain the nucleus of your answer. When the DCL is 21 kW, you might be right about the total available at that moment being 126 HP. :)

    Did you see that 21 kW value for DCL reported on a scan tool? It changes, computed by the battery smart unit based on conditions affecting the battery. The repair manual gives the "normal" range as 30 kW or less.

    dcl.png
     
    #3 ChapmanF, Feb 17, 2023
  4. Abarnabe

    Abarnabe Member

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    yes, I've seen that value with a scan tool and Hybrid assistant app, 21kw is the max value in S4 at about 35 C,in other warm up stages and temperatures is less than that. The charge current limit CCL is instead 25kw, I guess because the nimh chemistry is 70% efficient and 30% of the charging power goes in heat.
     
    #4 Abarnabe, Feb 17, 2023
    Last edited: Feb 17, 2023
  5. ChapmanF

    ChapmanF Senior Member

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    Right. So 21 kW is the maximum calculated value you have captured on a scan tool in the vehicle(s) where you've looked, under the conditions you've driven.
     
    #5 ChapmanF, Feb 17, 2023
  6. Abarnabe

    Abarnabe Member

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    Hmmmm, the screenshot shows a dcl of 21kw, but a battery output peak of 26kw, so the software limit is unable to stop battery output above 21kw
     

    Attached Files:

    #6 Abarnabe, Feb 17, 2023
  7. ChapmanF

    ChapmanF Senior Member

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    Probably used as input to a control algorithm that treats it as a target, while other rapidly-changing things are going on.
     
    #7 ChapmanF, Feb 17, 2023
  8. fuzzy1

    fuzzy1 Senior Member

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    My original 2010 brochure claims 134 hp (100 kW), comprised of 98 hp (73 kW) from the ICE, and 36 hp (27 kW) from the battery. It doesn't go into inverter or other details or limits.
     
    #8 fuzzy1, Feb 17, 2023
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  9. Tideland Prius

    Tideland Prius Moderator of the North
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    To be fair, Toyota revised this to 121hp for Gen 4. I can't remember what else has changed as the power is only derated to 95hp (torque remains the same but at a much lower 3,600rpm). They said they revised it to better match the output.
     
    #9 Tideland Prius, Feb 22, 2023
  10. ChapmanF

    ChapmanF Senior Member

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    According to numbers I linked to here (and do not independently know the accuracy of), MG1's power capacity took a steep reduction from Gen 3 to Gen 4.
     
    #10 ChapmanF, Feb 22, 2023
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  11. Tideland Prius

    Tideland Prius Moderator of the North
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    Usually that’s offset by a reduction gear, no? The Gen 2 had 295lb-ft of torque from MG2 and now it’s down to 151lb-fr or something like that.
     
    #11 Tideland Prius, Feb 22, 2023
  12. ChapmanF

    ChapmanF Senior Member

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    A reduction in a torque rating, you can offset with a reduction gear. Spin the thing faster but at lower torque. Power is torque ✕ rpm, so you're just achieving the same power rating in a different way.

    But lower the power rating itself, and you've just ... lowered the power rating.

    Starting with Gen 3, they have been using reduction gearing between MG2 and the PSD, so they can use a smaller lighter MG2 that spins faster.

    To my knowledge, they've never done that with MG1 so far.
     
    #12 ChapmanF, Feb 22, 2023
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  13. priusman15

    priusman15 New Member

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    A little bit wrong! 21 kw = 28.16146 hp

    kW to hp - Kilowatts to Horsepower Conversion Calculator
     
    #13 priusman15, May 7, 2024
  14. ChapmanF

    ChapmanF Senior Member

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    In "21 kW", you have a value stated with two significant figures.

    When you convert that to HP and round as needed to preserve the number of significant figures, you get ... 28 HP.
     
    #14 ChapmanF, May 7, 2024
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