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Inverter coolant heat exchanger?

Discussion in 'Gen 2 Prius Technical Discussion' started by #1 Toyota salesman, Jul 5, 2018.

  1. #1 Toyota salesman

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    Anyone toyed with the idea of adding a small oil/trans cooler inline to the inverter/transaxle coolant loop?
    I've even seen a few Honda radiators, so small, they's would fit without impeding airflow to the current rad/condenser

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  2. #1 Toyota salesman

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    Really? JUST me?
    I read they added one on later models, is this correct?

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  3. ChapmanF

    ChapmanF Senior Member

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    Your Prius generation already has the transaxle cooled by SLLC pumped through a heat exchanger behind the front bumper with electric fans behind it. Can you explain why you're thinking that's not adequate?

    -Chap
     
  4. Stimp

    Stimp Member

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    Yup, car takes good care of itself. Here's the temperature log of an 80 mi summer highway run with AC going. Fresh coolant in both loops and fresh atf in the transaxle.

    Screenshot_20180614-213707.png
     
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  5. #1 Toyota salesman

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    Because my dumb nice person didn't realize there was one...that's why lol

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  6. edthefox5

    edthefox5 Senior Member

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    Your on the right track. Every now and then someone will say extra cooler for inverter coolant because cooler inverter fluid better inverter efficiency.

    The G2 has its own inverter rad integrated and in the bottom of the ice rad. Toyota got smart on the G3 and added a separate & not connected inverter rad to counteract the heat soak. That has a fan on it.

    But no matter what the cooler needs a fan. You cannot stick a rad in the wind. It will do poorly needs a fan force sucking air because sooner or later you have to stop for a light. Temp quickly rises.

    BUT....if there was any kind of room to add an auxiliary cooler to a G2 that has a fan and didn't muck up existing airflow to the condenser that would have excellent results & better mileage. The problem is there is no room anywhere for it without a major pipe job.

    Need a bigger car.
     
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  7. edthefox5

    edthefox5 Senior Member

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    I see much higher inverter coolant temps down here in florida. Park the car and wait 3 minutes and measure the inverter coolant again it quickly rises to about 150f just sitting there.
     
  8. #1 Toyota salesman

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    But with an electric fan, you could place the radiator "face down" most anywhere, perhaps beginner the transaxle etc...
    Oil, PS, and differential coolers are often done this way in road racing.
    I know for the ICE, there's a point of diminishing returns, as far as too cool of a coolant temperature. But I know for electronics you can never have them too cool.

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  9. edthefox5

    edthefox5 Senior Member

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    I agree with your thinking. Go for it.

    Would love to see the results. The inverter and trans would love it. Remove the flow from the rad as there is massive heat soak when you shut the car off from the ice rad. I did some tests way back in the day. It goes from 120-140 degree's in the dead of summer in FLA to 160 when you shut the car off. They fixed that in the G3. They had too... the new mgs and the inverter are much more powerful and require better cooling.
     
  10. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I am confused.
    Are you wanting to add ATF cooling to the ATF in the transaxle, or an additional radiator in the coolant loop for the inverter and transaxle?

    [​IMG]
     
  11. #1 Toyota salesman

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    I might have to crawl around under there, and see where there might be space four. And start Google searching some small heat exchangers with fans mounted already.
    or perhaps a small powerful fan, and base the heat exchanger around that.

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  12. #1 Toyota salesman

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    Standalone radiator for the inverter/transaxle cooling loop

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  13. Stimp

    Stimp Member

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    No extra radiator is going to prevent a rise in temperature after the pump stops circulating coolant. Keep in mind 150/160 degrees is inches from a 190 degree engine. But if the system can be improved go for it, I'll gladly follow along. Seems like there is an old post where someone did this mouldering around in PC.
     
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  14. edthefox5

    edthefox5 Senior Member

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    In a G2 the inverter heat soak comes from it being in the same housing as the ice rad. They touch each other. The g3 does not suffer from that so yeah an extra separate rad in a g2 will help with the heat soak and make it much easier to keep cool.

    Many old posts about this.