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Old 01-17-2017, 09:53 AM   #97 (permalink)
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Join Date: Dec 2007
Location: Germantown, WI
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CM400E - '81 Honda CM400E
90 day: 58.68 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
Team Toyota
90 day: 49.53 mpg (US)

Daox's Insight - '00 Honda Insight
90 day: 64.33 mpg (US)

Swarthy - '14 Mitsubishi Mirage DE
90 day: 56.69 mpg (US)
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Originally Posted by toc View Post
I question this!

If it were me, the thermostat being fully open at 197, I'd open it before this - say 190.. if the thermostat opens, the radiator will provide cooling providing the airflow isn't restricted (by the grill block). Close it at 180, so that the thermostat should be reasonably closed. (Play with the numbers so that you are operating in half of the thermostat range - grill block closed as thermostat closes)..

It'll use more energy to leave it closed til the fans are required (206 is too close, you'll miss free cooling from airflow!) - (fans use electricity).
I do think it will require tweaking. However, I would ideally (at least for now to start testing) like it to operate as such (I'll leave specific numbers out as tweaking will definitely be required):

Grill block closed at start up.
Engine warms up.
Thermostat starts to opens up, radiator starts to warm up, but still provides some cooling.
Thermostat is fully open, radiator is fully saturated with heat.
Just before coolant fan turns on, open grill block. At this point you have the highest delta T you will see, and your radiator will be used the most efficiently.
As thermostat closes, close grill block. As you mentioned, this will require tweaking this temperature.
Repeat until keyed off, then close grill block.

If I set the close temperture to 180F, I don't think it will ever close because the coolant will not get that cool unless I am blasting the heat. The thermostat on the Insight is a 195F thermostat. So, maybe close it at 190-195 instead? I ideally want to only push air through the radiator when it is saturated, but before the e-fan turns on. 206F may well be too late. I fully agree we want to avoid using the cooling fan. However, I'd also like to reduce the amount of cycling as much as I can too for longevity sake.

Eventually, it would be great to setup a comparison loop that opens and closes the grill incrementally as needed. But, that part is on the back burner until I get this thing in and tested.
Current project: Adding regenerative braking to the Mirage
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