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Electric Fan clutch

ak diesel driver

ak diesel driver

6.5 driver
Messages
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Location
alaska
So for those who want accurate fan clutch engagement this could be for you. I know on my 96 the fan clutch has never engaged the entire time I've owned it. Living in cooler climates does have it's advantages. I even tried modding the spring to no avail. This clutch will only work with the spin on fan clutch so if you have the bolt on clutch you'll have to upgrade it as well. The clutch will need to be controlled by an aftermarket electric fan controller such as
http://www.ebay.com/itm/350455203392?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
For myself I'd use this style vs the radiator probe as it would read water temps in the head and be more accurate but either style would work.
The clutch is also designed to be a variable engagement but for simplicity I'd just have it be on or off. This probably won't cool as effectively as the hydraulic version that is in the works as it's still a viscous clutch and will only engage about 90% of shaft speed. But unless your a super heavy tower most of us just need one that will turn on and off as needed without any delays.
You also need to use the Ford fan that this clutch uses which is part number YA250 and IIRC measures 20.3" in diameter.
I have not done this mod yet but plan to on my 99 so the only thing I'm not sure of is the distance the fan will have to the shroud.
 

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Thanks for posting.

I had been seeing clutches out the salvage yards that had the electrical connector in the middle (viscous). Was curious about the correct hub diameter to mount one.
 
Yeah, I just saw some images on google for electronically controlled viscous fans the other day. Hayden has some but that is about all I have investigated them. Hayden's website mentioned newer cars the ECM can electronically engage the viscous fan instead of the metal thermo spring. This is helpful for ac, transmission temp or other heat load that might not cause coolant temp to rise to the point of engagement or will lag too much. I thought it was interesting and seemed fairly doable.
 
Love the EV fan clutches. Good idea as I was thinking of the unavailable stand alone PWM controller for them and never thought of just on-off for them. Did a lot of work with them on Trailblazer SS to get the AC to cool off when it went over 105 out. Result was sealing the stack and helping design a thicker radiator available here. Our 6.5 trucks do not have a radiator thickness issue - they have an airflow issue.

My 2003 Dodge Cummins has one. Full fan on a cold engine due to AC demand.

The biggest issue is sucking the wires through the fan. The reliability is just short of the word unreliable and replacements are expensive. Same standard as the electrics and Obsolete spring thermal clutches..
 
I found a controller that would let you vary it but it seemed to me to be more complicated, more expensive, more to fail
 
I like the idea of varying engagement. ON/OFF seems like a lot of cycling in stop and go traffic or mild climate for HVAC or light to medium duty. To me ON OFF is good for a dragster. Why engage it fully if say 30% would do it. Maybe an in cab adjustment or override would be the ticket.

Maybe instead of using head temp as turn on point ON/OFF use a more average temp of the radiator and slowly increase fan engagement. Like the progressive water injection controllers do with boost if that makes sense.

Kinda thinking and might should add this to Leroy's thread.

I wouldn't want there to be a lot of cool flushes of water over the heads if say the AC cuts on fan 100% for AC cooling but the EC is ok.

I don't know if this would happen often but wouldn't want it to..... Engine is running normal stats open radiator maintaining temps. Turn on AC and turns fan on fully. It cools the radiator and stats start to close radiator gets cooler then you hit a grade and stats open with hot engine and cool radiator flushes engine.

I read they will start up engaged then after some warm up they disengage. So will they roar on first starting and warm up????
 
I don't know what numbers would be but something like this.....

Use a temp sender in mid to lower part of the radiator.

If normal operation is say 140F or cooler but under load over 160F radiator temps cause engine temps climb on dash guage and you need to keep mid radiator under 180F to keep ECT below 200F

Then the controller should engage fan at about 10% increments for each degree at 161 F thru 170F. Or what ever saftey factor is needed and to smooth out control so its not so abrupt and you only engage as much as you need.

I don't know how the controllers work normally. Are they turn on at 180F and off at 170F and heat transfer naturally periodically cycles the fan even if it was ON/OFF ???
 
schiker said:
I like the idea of varying engagement. ON/OFF seems like a lot of cycling in stop and go traffic or mild climate for HVAC or light to medium duty. To me ON OFF is good for a dragster. Why engage it fully if say 30% would do it. Maybe an in cab adjustment or override would be the ticket.

I read they will start up engaged then after some warm up they disengage. So will they roar on first starting and warm up????
Click to expand...

Why? Because there isn't an off the shelf controller or kit offered to control the EV fan clutch. So in a stroke of KISS genius the OP figured out why not just on/off it and solve the "turn on delay" spring thermal has. Again the way you are thinking is already implemented in the vehicles and applications EV clutches come factory from. Sadly it's in the ECM. Specifically what is 30%, 50%, 90%? Shaft RPM vs fan RPM right? So here is the big challenge: how do you use a PWM signal to get the desired lockup %? Sure add complexity and monitor Fan RPM and with a feedback loop biased on tables you vary the PWM signal to get the desired RPM vs engine RPM, oh wait you need to monitor input RPM too - this is getting complex for a stand alone controller.

To be clear a 50% duty cycle PWM signal to a EV fan clutch doesn't mean 50% lockup.

The EV fan clutch doesn't really care about cycling like "dry" clutches do with wearout from locking up.

"So will they roar on first starting and warm up????"
YES. The only difference in a EV fan clutch and the standard factory issue spring thermal fan clutch is the control. Thus the fan clutch has "morning sickness" that is a normal part of it's operation.
 
I forgot the stack would normalize somewhat. If ac load increased it would warm radiator doesn't it????? So a big thermal swing is unlikely.

Just giving my thoughts. I assumed the stand alone controller could controll the fan fairly easily but i guess i dont know how it can be programmed or commanded to control the fan.

AK can you describe the stand alone controller? If it's still on/off but you can adjust the % lock up then I still like the idea being able to adjust lock up %. For example leave it at say 50 % power at an early set point in mid radiator or stack temp probe and if gauge temp isn't controlled crank the power. Or when u anticipate a hill crank up the power before a hill.
 
Hope this helps understanding of how the system works and the challenges we are trying to overcome with different fan clutch options.

If the radiator isn't hot turning the fan on early just sucks power you need for the hill. So the controller commanding the fan to lockup at the setpoint eliminates the heat the radiator and the thermal spring delay. The clutch still has a small delay in coming 100% on as the silicone moves to the working chamber. So by the time the tstat opens and heats the radiator from high throttle the fan will be locked in.

The thermostat regulates the engine temperature within it's limits. You shut fuel off on a long downhill grade and the airflow through the cylinders will completely cool the engine off. So much so you can smoke white with little fuel input going downhill.

The max temperature of a condenser I have seen is 160 degrees at ~250 PSI head pressure if I recall correctly. That is not hot enough alone to kick on the fan let alone the heat sink of the radiator. KD's fan clutch is set for 180 degrees and factory is 195.
 
I guess in my minds eye I can envision a fairly simple progressive controller.

Having exact slippage or exact fan speed is not that critical just so it doesn't huff and puff and hunt for slippage adjustment. Or cause some weird interaction such that it roars on and off ??? I think it would be ok if at idle 50% duty cycle signal would provide say anything steady between 30-60% slippage but at 2000 rpm it might slip 70-80%. Just so you can kind of sorta control how hard the fan pulls.

If electric fans can work for light duty operation I think some adjustable slippage rate would be ok. I would think just so you could basically increase pull of the fan with a controller when you wanted to. Say 2 setting (normal/ tow haul) with AC override????

Anyone have link to stand alone controller?

I don't see much but did see this

http://www.hortonww.com/en-us/produ...sterfandriveswithdigitalinterfacecontrol.aspx
 
Best bet is to check with Horton to see whether the EV clutch will allow PWM application or slippage. If it does not, then everybody will likely walk away with disappointment.


Seems like a push / pull combination is ideal.

Pusher(s) to kick-in for moderate heat relief.

And then the motor driven fan to kick-in 100% to completely dump the heat.
 
Has anybody found anybody using an EV fan clutch in a non factory equipped application? I did some searching on the DODGE boards, and found where they said it required a PWM control, not an on off signal to work. They tried using one from an 03+ truck which was a BORG WARNER EV fan clutch, and retrofitting them to athe older 1st gen trucks. They powered it directly and said it just wouldn't engage properly. Somebody said it required a pulse width modulated signal to properly enagage the clutch.
 
In testing my implementation of the Hydraulic clutch using a new/reman clutch and updated control solenoid valving this setup runs the fan similar to an unlocked fan clutch. Just enough drag that the fan turns and moves air without being engaged. This is good because for normal non-ac driving the water temp stays right at operating temperature and hasn't needed clutch engagement intervention. Less temp swing, keeps air moving through the stack and through the engine compartment (reduce heat soak under hood). So, this hydraulic setup isn't just ON or OFF. For all intensive purposes it has behaved like a thermostatic clutch except it engages fully and precisely/optimally when needed.

There is a driver switch that:

Commanded ON
Commanded OFF
Automatic Control

Test vehicle is a 1994 K2500 LD Ex Cab SB 3.42 Gears and 265 Rubber.
 
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Somewhere between those 2 is what is needed I would think Ak. I can't imagine the little solenoid would require that much amperage as the Derale unit?

Now I guess we might assume its not at all linear duty cycle vs slip and WW might be saying on one day (given temp, humidity, elevation etc) 50% duty cycle might produce 30-40% slip. But at another environment it might be 15-20% slip or a lot more depending. And it might vary according to load on fan. That doesn't bother me as long as it doesn't surge with a set PWM signal too bad.

IF fully on is considered 100% duty cycle and it does not work command fan on fully then maybe the controlling valve has 2 or more ports such that its using a ports to multiply the mechanical ON/OFF frequency of the flow. Might take some other factor of 100 pecent duty cycle to engage fully ( which then is still not locked up 1:1 but what ever the working fluid will produce through the port ie only 10% slip ????.

I could see maybe a 2 port piston equal spaced with a cross flow passage you would have to have a back and forth motion to allow working fluid to pass through to the working chamber. The PWM might have to be adjusted to the viscosity of the working fluid and the shear load to really control the engagement % precisely.
 
UD,

Have you ever tried to adjust pressure on the hydraulic engagement/disengagement mechanism to try and control the amount of slip on the clutch?

How does that work? I will assume its not easy to feather engagement but is it doable?
 
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