- Mon Mar 21, 2016 10:59 pm
#6643
Feeling I owe you, and more importantly the community further explanations....
In the first, the "sensor" for the switch was mounted at the top of the radiator, in contact with the "fins", and also as close as possible to where the "hot" coolant entered the radiator. Air temp bore much less influence than the temperature of things conducted through the radiator to the sensor. The fact the fan when running, was enough to lower the temp in that area so the fan could turn off was surprising. However, it's apparent that placing the sensor where it's not in direct contact with the coolant had an adverse effect on things, which was my primary impetus in doing this particular test.
As evidenced by test 2, placing the sensor within the coolant path resulted in the fan coming on 10F lower than when the sensor was elsewhere, and similarly had the engine running 10F cooler, give or take. However, unlike the first test, the fan once started it did not turn off.
This is relatively easy to explain: the thermostat, rated 195F, opened at that temp and the fan came on shortly after. Even if the coolant temp behind the thermostat caused it to close, the temperature of the coolant after the stat wouldn't set in the hose long enough to cool off enough to turn the fan off. The fan switch has an approximate 20F span between "on" and "off", so if the fan came on at 200F, it would turn off at ~180F.
Sensing the coolant temp in this manner was the only method out of the three that resulted in both "normal" engine temperatures and fan cycling. The latter being important as it, as tested, demonstrates the ability of the radiator to remove heat from the coolant and retain significant reserve cooling capacity.
This also demonstrates that if the forward motion of the vehicle is satisfactory so as to cool the coolant adequately, the fan won't run.
No laws of thermodynamics violated in the process.
The only inaccurate data presented wasn't technically inaccurate but only appeared so due to an unfortunate omission, which I've corrected above.
While we're at this banter, maybe you can explain why removing the thermostat from some engines results in overheating while in others it doesn't?
... in spite of cooling fan operation....
Xnke wrote:Cx500tc:Pay attention, please.
You are wrong. Tough luck. If you want examples, I can give you literally hundreds. With documentation.
Your fan control system was not properly adjusted to maintain engine temp. Sorry. You've done it wrong.
Case 1:The "switch" was set to turn on at 200F for both of the above tests.
If you fan did not kick on until the AIR temp coming through the radiator was 210 degrees, there is NO POSSIBLE WAY that you could have controlled the engine temperature.
The AIR temperature will always be lower than the coolant temperature...if the air temperature was HOTTER than the coolant temperature, then you would have had to add heat from an outside source! You can't get more energy out of a heat exchanger than you put in. So, since you fan cut-on temperature was 210 degrees, IT WOULD BE NORMAL to have the coolant temperature rise to 220 degrees...you are removing 10 degrees of heat from the system. In order to prevent the engine from overheating, you would have to adjust the fan cut on temperature to LESS than 210 degrees! In this case, assuming that when the fan is running, the radiator will continue to remove 10 degrees of heat, adjusting the fan cut on temperature to 180 degrees would result in a coolant temperature of 190 degrees. The reason your fan control system didn't work? You were operating the cooling system outside of it's specified control limits.
Case 2:
In this case, you demonstrate again, that your radiator, with the cooling fan you installed, was capable of removing 10 degrees of heat from the cooling system. Nothing spectacular here, except that you needed to set the cut-in temperature lower in order to get it under control of the thermostat. I repeat:
You were not turning the cooling fan on within the control range of the engine thermostat. You were operating the cooling system OUTSIDE OF SPECIFIED LIMITS.
Also, how did you change the temperature setting of the thermostatic switch? You said it turned on at 210F in test one...but you used the same switch in test two, and it magically turned on 10 degrees cooler? They don't work that way, unless YOU changed the cut-in temperature by using an adjustable fan temperature switch. Of course, if you did...why not set the fan cut-on temperature to operate within the control range of the engine thermostat?
In the first, the "sensor" for the switch was mounted at the top of the radiator, in contact with the "fins", and also as close as possible to where the "hot" coolant entered the radiator. Air temp bore much less influence than the temperature of things conducted through the radiator to the sensor. The fact the fan when running, was enough to lower the temp in that area so the fan could turn off was surprising. However, it's apparent that placing the sensor where it's not in direct contact with the coolant had an adverse effect on things, which was my primary impetus in doing this particular test.
As evidenced by test 2, placing the sensor within the coolant path resulted in the fan coming on 10F lower than when the sensor was elsewhere, and similarly had the engine running 10F cooler, give or take. However, unlike the first test, the fan once started it did not turn off.
This is relatively easy to explain: the thermostat, rated 195F, opened at that temp and the fan came on shortly after. Even if the coolant temp behind the thermostat caused it to close, the temperature of the coolant after the stat wouldn't set in the hose long enough to cool off enough to turn the fan off. The fan switch has an approximate 20F span between "on" and "off", so if the fan came on at 200F, it would turn off at ~180F.
Case 3:Now, I admit this one could be confusing to most people. I did, inadvertently, forget to include the adjustment to the fan temp setting. I adjusted it to turn on at 180F, which means the radiator's ability to radiate heat to atmosphere before the coolant reached the sensor was included. As in the fan only turned on if the coolant temp at the lower radiator hose reached 180F, and as mentioned before, it turned off if the coolant dropped below ~160F.
This one simply doesn't make sense. I suspect data was collected inconsistently, but we'll roll with it. You are telling us, that you did not turn on the fan until the ALREADY COOLED liquid coolant leaving the radiator was 200F. That means the coolant entering the radiator (that we have established through test 1 and 2 above can remove at least 10 degrees of heat energy when used WITH THE FAN ON and therefore we can safely assume it can NOT remove 10 degrees of heat with the fan off) was AT A MINIMUM of 210 degrees, which means the engine was already on it's way to overheating. But According to test 1, the coolant exiting the radiator would have had to heat the switch to 210 degrees to activate the fan...which would mean coolant entering the radiator would have had to be at least 220F...again, well over the temperature at which the thermostat can control the engine coolant temperature. So yet again, you are operating the system outside of the specified limits. And yet you claim that the coolant temperature entering the radiator coming from the engine, was less than or equal to the temperature of the coolant exiting the radiator and entering the engine?
Sensing the coolant temp in this manner was the only method out of the three that resulted in both "normal" engine temperatures and fan cycling. The latter being important as it, as tested, demonstrates the ability of the radiator to remove heat from the coolant and retain significant reserve cooling capacity.
This also demonstrates that if the forward motion of the vehicle is satisfactory so as to cool the coolant adequately, the fan won't run.
So, now that we have established that not only are you wrong about how most OEM's control and monitor coolant temperature, we have also established that you can magically violate the laws of thermodynamics that govern heat exchangers, or perhaps we have established that the laws of thermodynamics weren't violated and you simply presented inaccurate data?Not wrong about OEM's, as evidenced by a few other posts.
No laws of thermodynamics violated in the process.
The only inaccurate data presented wasn't technically inaccurate but only appeared so due to an unfortunate omission, which I've corrected above.
I invite you to try the testing again, but I would expect after reading this, you'll understand why I take your results with a grain of salt.No need to test again. Feel free to take what I say with either salt or strychnine.
While we're at this banter, maybe you can explain why removing the thermostat from some engines results in overheating while in others it doesn't?
... in spite of cooling fan operation....