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Invertor Cooling System

Discussion in 'Gen 2 Prius Accessories & Modifications' started by NoMoShocks, Apr 21, 2007.

  1. NoMoShocks

    NoMoShocks Electrical Engineer

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    I am reading the book, "The Prius that Changed the World". Chapter 9 talks about three seperate radiators for Air Conditioner, ICE and Invertor ICs. Of course, they are dicussing the design of the original Generation 1, but it made me wonder about those blocking the grill in the G2. If they are only monitoring ICE temperature? Is there still a seperate cooling system for the Invertor ICs? Could that be running on the hot side, shortening the life of those semiconductors?
     
    #1 NoMoShocks, Apr 21, 2007
  2. faith2walk

    faith2walk Upgraded again

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    <div class='quotetop'>QUOTE(NoMoShocks @ Apr 21 2007, 11:48 PM) [snapback]427607[/snapback]</div>
    Good question...at my 100k checkup, they charged me twice for the coolant flush (actually just a drain and fill, since the prius can't be flushed, or so they told me). The prices were different and they entoned that it was because the systems were separated. Not sure how and didn't have the time to find the details about it. Would like to see a flow schematic on it, if anyone knows where to get one.
     
    #2 faith2walk, Apr 22, 2007
  3. Bill Merchant

    Bill Merchant absit invidia

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    Yes, the inverter radiator is the bottom 6 inches (15 cm) or so of the main radiator, engine coolant runs in the top two-thirds. The AC radiator is separate. I think most people concerned about engine temps with a blocked grill are monitoring the coolant for the engine, not the inverter, though you could with a CAN view, I don't know about the Scan Guage. The Prius is not too hot blooded, I think you should be safe with a blocked grill on into the 50°F (10°C) area. If you hear the radiator fans come on, unblock the grill!
     
    #3 Bill Merchant, Apr 22, 2007
  4. NoMoShocks

    NoMoShocks Electrical Engineer

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    <div class='quotetop'>QUOTE(Bill Merchant @ Apr 21 2007, 10:14 PM) [snapback]427669[/snapback]</div>
    Thanks Bill!
    I think next winter, if I want to experiment with blocking the radiator, I will go under the hood and try blocking just the top section that I can monitor with the ScanGuage only. It should provide the same boost in economy, without blocking the Inductor cooler on the lower 1/3.

    The Scanguage can monitor Engine water temp and Air Intake Temp, so if someone blocks their grill, I would be afraid that the ScanGuage monitoring water temp might be the ICE cooler, and the Invertor could be running hot enough to shorten the life the ICs, but not so hot as to make any warning lights come on.

    I don't plan to get a CANVIEW, because of the need for a second LCD in 2007 models.

    According to the book I am reading, which again is talking about the development of the G1, the Invertor IC cooling radiator was considered the most critical, then AC, and finally, the ICE. It talks about how they wanted to use a two layer radiator design with AC up front and then split second layer behind with ICE on top and Invertor Cooler on bottom extending below the AC so that part of the Invertor cooler was getting air that had not passed through the AC condesnor.

    Anyway, I guess they ran out of time on G1 and went to three layers of radiators, but from Bill's added information, it is apparent that G2 is back to two layers with Invertor cooler on the bottom half of one layer.

    One thing I meant to ask you today Bill, has anyone talked about adding a transmission cooler? I added one on my Pontiac Sunbird back in the 80s, but it backfired on me. I didn't realize I had run one of the rubber hoses too close to a body weld, and it gradually wore a hole in the hose when Michele and I were on a trip from San Luis Obispo, CA to Sierra Vista, AZ. Going over the San Bernadino Pass, all of a sudden, the car had no power so I limped into a gas station and imediately found the leak. Bypassed the cooler, filled up the tranny and we were on our way again. Guess I do a search, and then maybe post the question if I don't find it has already been talked about.
     
    #4 NoMoShocks, Apr 22, 2007
  5. Bill Merchant

    Bill Merchant absit invidia

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    I don't recall any discussions of a separate "transmission" cooler. The HSD in not like an automatic or manual conventional transmission.
     
    #5 Bill Merchant, Apr 22, 2007
  6. efusco

    efusco Moderator Emeritus
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    Many of us do/have monitored the inverter temps in the early stages of experimenting with the grill blocking. That's how we arrived at the conservative temp limit of 50 degrees F outside temp for removing the lower grill block--some of us were observing occasional MG2 temps above 120 degrees when it was over 50 degrees outside but never that high when under 50 degrees. Supposedly the inverter is built to handle temps closer to 240 degrees, but clearly prefers to operate in a cooler range.
     
    #6 efusco, Apr 22, 2007
  7. apriusfan

    apriusfan New Member

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    <div class='quotetop'>QUOTE(Bill Merchant @ Apr 21 2007, 11:36 PM) [snapback]427692[/snapback]</div>
    The CVT of the Prius is closer to a manual transmission - no torque converter.
     
    #7 apriusfan, Apr 22, 2007
  8. NoMoShocks

    NoMoShocks Electrical Engineer

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    <div class='quotetop'>QUOTE(apriusfan @ Apr 22 2007, 12:44 PM) [snapback]427892[/snapback]</div>
    If the drive pulleys and drive belt are imersed in transmission fluid (I am not saying that they are) then I would argue it is more like an automatic transmission with friction surfaces in oil.
     
    #8 NoMoShocks, Apr 22, 2007
  9. jiepsie

    jiepsie New Member

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    <div class='quotetop'>QUOTE(NoMoShocks @ Apr 22 2007, 10:36 PM) [snapback]427907[/snapback]</div>
    There are no drive pulleys or belts, the gears are always connected at a fixed ratio. If it was a CVT transmission with cones and belts, yes, there would be heat and friction. The previous Mini had an automatic CVT like that, the computer in that system would monitor the oil temperature and adjust the pressure on the belt if the oil got too hot. This is way different, don't let the words transmission or CVT lead you to think it's like a regular transmission or CVT.

    Read about how it works at eahart.com (nice animation too).
     
    #9 jiepsie, Apr 22, 2007
  10. Tempus

    Tempus Senior Member

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    <div class='quotetop'>QUOTE(NoMoShocks @ Apr 22 2007, 04:36 PM) [snapback]427907[/snapback]</div>
    There are no pulleys and no drive belt.
     
    #10 Tempus, Apr 22, 2007
  11. NoMoShocks

    NoMoShocks Electrical Engineer

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    <div class='quotetop'>QUOTE(Tempus @ Apr 22 2007, 01:49 PM) [snapback]427912[/snapback]</div>
    Thanks, Now, I realize it is not truely a CVT, but simply a Power Transder device. I found the cutaway and can see that the chain inside is a single ratio chain, and therefore, I must agree with all that it is more like a differential or manual transmission. The behavior similar to a true CVT is achieved by varying the electrical load. Whatever the electric motors do not consume goes directly to the wheels.
     
    #11 NoMoShocks, Apr 22, 2007
  12. Bill Merchant

    Bill Merchant absit invidia

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    I'm not sure you fully grok the HSD, Larry, even now. The chain in the cut away is a fixed ratio linkage to get the power from the HSD to the axels, it's just an offset from the power train. The magic is in the HSD and the way the computer can turn motors into generators and change their direction to get the desired output to the chain and hence the wheels.

    Study Bob Wilson's Prius Power Flow.

    If you are a more visual person, Graham Davies explanation of the Power Split Device may illuminate your understanding.

    John1701a has a great document on the Power Split Device too, as well as one on Power Flow.

    See why I have HSD on the brain? :)
     
    #12 Bill Merchant, Apr 23, 2007
  13. phidauex

    phidauex Junior Member

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    <div class='quotetop'>QUOTE(Bill Merchant @ Apr 23 2007, 12:35 AM) [snapback]428193[/snapback]</div>
    Its ok, Larry, almost no one truly groks the wonder of epicyclic gearing with multiple power inputs. Hell, it took me two years just to grok the 'belt and cone' CVT in my motor scooter (110 MPG, baby). It exhibits remarkably complex behavior from a very limited number of parts, much like the power split device.

    Engineering finesse beats manufacturing brute force once again. :)

    -Sam
     
    #13 phidauex, Apr 23, 2007
  14. NoMoShocks

    NoMoShocks Electrical Engineer

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    I will look over Bills links. The CVT with the variable cone pullys and such was from my 2006 Honda Civic Hybrid.

    How dare a confuse the two.

    The first one I had was on a minibike when I was eight or nine years old.
     
    #14 NoMoShocks, Apr 25, 2007
  15. Pinto Girl

    Pinto Girl New Member

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    <div class='quotetop'>QUOTE(NoMoShocks @ Apr 25 2007, 01:10 AM) [snapback]429600[/snapback]</div>
    Check out the planetary transmission used on the Model T, also, if you get a chance. It's actually in some ways very similar to that of the Prius.
     
    #15 Pinto Girl, Apr 25, 2007
  16. Rangerdavid

    Rangerdavid Senior Member

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    #16 Rangerdavid, Apr 25, 2007
  17. Bill Merchant

    Bill Merchant absit invidia

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    <div class='quotetop'>QUOTE(Rangerdavid @ Apr 25 2007, 05:01 PM) [snapback]430188[/snapback]</div>
    That's why I put it first. The others have good animations that help make sense of a motor reversing direction as the car accellerates.
     
    #17 Bill Merchant, Apr 26, 2007
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