Invertor Cooling System

[NoMoShocks]

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?

[faith2walk]

<div class='quotetop'>QUOTE(NoMoShocks @ Apr 21 2007, 11:48 PM) [snapback]427607[/snapback]</div>

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? [/b]

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.

[Bill Merchant]

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!

[NoMoShocks]

<div class='quotetop'>QUOTE(Bill Merchant @ Apr 21 2007, 10:14 PM) [snapback]427669[/snapback]</div>

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!
[/b]

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.

[Bill Merchant]

I don't recall any discussions of a separate "transmission" cooler. The HSD in not like an automatic or manual conventional transmission.

[efusco]

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.

[apriusfan]

<div class='quotetop'>QUOTE(Bill Merchant @ Apr 21 2007, 11:36 PM) [snapback]427692[/snapback]</div>

I don't recall any discussions of a separate "transmission" cooler. The HSD in not like an automatic or manual conventional transmission.
[/b]

The CVT of the Prius is closer to a manual transmission - no torque converter.

[NoMoShocks]

<div class='quotetop'>QUOTE(apriusfan @ Apr 22 2007, 12:44 PM) [snapback]427892[/snapback]</div>

The CVT of the Prius is closer to a manual transmission - no torque converter.
[/b]

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.

[jiepsie]

<div class='quotetop'>QUOTE(NoMoShocks @ Apr 22 2007, 10:36 PM) [snapback]427907[/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.
[/b]

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).

[Tempus]

<div class='quotetop'>QUOTE(NoMoShocks @ Apr 22 2007, 04:36 PM) [snapback]427907[/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.
[/b]

There are no pulleys and no drive belt.