Anyone install the Mercedes Benz electrically controlled fan clutch on a 403 yet? (Mike Perez)

[Tom Pryor]

Karen Bradley has installed her MB fan using the EBL software and the GM
based controller. As i understand it, most any of the EFI controllers can
actuate our MB viscous fan clutch solenoid. Most EFI devices can turn and
off a fan or Fan clutch, but cannot modulate for soft start and reduced
duty cycle (RPM) which means less noise and less cooling

I believe Karen would entertain conversations on the matter. In one of the
last Emails we traded she had the following comments:
KB

 

[billvv]

Tom,
Is the soft start/RPM modulated control one that has always been provided with the kit, or is this a new version? I have an uninstalled kit from last
May and wondering if that controller has those features.
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015.

 

[SteveW]

Hello Tom -

And the same question from Steve W out in Southern California.

I recently installed the kit that I had purchased quite a while ago. My controller was a little different than your instructions - clockwise vs
counter-clockwise adjustment for temperature setting - and mine seems not to have the wide range indicated in the write-up. Tuned it in to energize
at around 210 and that was very near the limit.

It works great. It looks great. And the manual engagement feature is seriously cool. As is the indicator light to see when energized.

Thanks for all of your work and your contributions to the GMC Motorhome community.

Steve W
1973 23' Yellow
Southern California

 

[Tom Pryor]

Bill VB and others. I have a test stand fitted with MB fan/fan clutch.
With a crude PWM setup installed it is able to start the Fan Clutch
softly. Still working on Duty cycle parameters and Temperature set
points........As I tell Kanomata, I'm running the race with a small engine
and a mostly healed replacement shoulder.
Be patient with me!

--
Regards,

Tom Pryor
4188 Limerick Dr
Lake Wales, Fl 33859
Cell 248 470 9186
1977 23'B named "CASPER", HARDLY ORIGINAL, (455 EFI) (Pwr. Drive)
(tailgate) (rear bunk beds)
(Webasto petrol boiler) (MB Elect fan clutch) (Brake reaction arms) BUT
STILL A WORK IN PROGRESS!

 

[billvv]

Tom,
Glad you're healing...

And glad you're working on the PWM control - I thought I'd missed something, but the soft start and PWM control will be great when you're finished
with it. Maybe have the EFI fan start signal as an input, then it can be 'start it when the EFI says so, with soft start, and control it to maintain
the current temp or lower'.
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015.

 

[hal stclair]

I put together an electronic fan clutch setup for my diesel swap and used a PWM controller with great hopes of very precise fan control. What I found
was a little different result than I'd hoped for. The PWM does provide a soft start and the manual override control which is nice but the fan doesn't
want to run at reduced fan speeds to throttle the cooling that I'd hoped would happen. It acts very similar to a stock properly working fan clutch in
this regards. The controller permits a wide range of temperature turn on settings that takes a little extra effort to set correctly also. I'd guess
the fluid can't work fast enough for the PWM pulse in the Hayden controller. Of course, the controller was designed for electric fans so wouldn't have
any 'buffering' to slow the pulses which is probably needed in my application. I'd be interested in knowing if the new PWM controller will have this
'buffering'?
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM

 

[johnny]

Let's note here, 'soft start' is a bit of a misnomer. The MB clutch, like the original, activates by opening a valve and letting the acting fluid
through. This gives a smooth engagement rather than a jerk. Just llike the original, turning it on isn't going to shock load the pump. What it
dies is modulate the fan speed. Whether this i worth the more complicated circuitry is open to debate, as those controllers go intop the field we'll
find out.

--johnny

--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[billvv]

Google helped me with some info.....

Here's a PDF of how GM describes the PWM viscous fan control - from 2002.
www.norcal-cobras.com/GTM/gm-tech-link/7_02_e.pdf

And here is a description with graphs.
http://www.ngclark.com.au/brands/horton/fan-clutch/vmaster-directly-controlled-viscous/

Both references describe using a PWM signal from the ECU, which likely has a PI or PID algorithm to prevent hunting or overshoot.

Control is a little tricky, because engine speed is changing as the controller is trying to maintain a controlled temperature. Pretty sure there needs
to be a fan speed feedback to the controller.

--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015.

 

[jim kanomata1]

The orton fan clutch is for low rpm (desila) only, not same as the one for
gasoline engine that turn much higher rpm.

On Fri, Feb 22, 2019 at 8:54 AM Bill Van Vlack via Gmclist <

> Google helped me with some info.....
>
> Here's a PDF of how GM describes the PWM viscous fan control - from 2002.
> www.norcal-cobras.com/GTM/gm-tech-link/7_02_e.pdf
>
> And here is a description with graphs.
>
> http://www.ngclark.com.au/brands/horton/fan-clutch/vmaster-directly-controlled-viscous/
>
> Both references describe using a PWM signal from the ECU, which likely has
> a PI or PID algorithm to prevent hunting or overshoot.
>
> Control is a little tricky, because engine speed is changing as the
> controller is trying to maintain a controlled temperature. Pretty sure
> there needs
> to be a fan speed feedback to the controller.
>
>
>
>
>
>
> --
> Bill Van Vlack
> '76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath,
> Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o
> mid
> November 2015.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[johnny]

Feedback is available. Matterofact, you can get for a bit of trouble the fan RPM and compare it to the engine tach. I see little need for it, bit
it's available. Feed the controller 5 volts and ground, and get the pulse train from it. 6 pulses per rev, so a divide by two chip will output a
pulse train which is accurate in a tach set for a 6 cylinder engine.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[billvv]

What controller would that be, Johnny? The one provided with the kit, the one Tom is experimenting with, or something else?
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015.

 

[johnny]

Not controller specific... the fan unit has a Hall Effect sensor in it and six tabs which the sensor can pick up. Those are the three unused leads.
One gets 5V, one gets ground, and the other will output a pulse train. This is the same as the Ford setup we first looked at, and appears to be much
the same on all the manufacturer's controlled fans. Modulating the valve gives a slight reduction in engine load relative to having it full open all
the time. No one has publicly owned up to the amount of benefit, but in a situation where every bit of mileage is chased, it may have some value. I
personally don't see the complexity as being worth it on a GMC, but I'm open minded about it and thus waiting for the results from the people sorting
it out. I don't think pulse width modulated vs on or off is going to be very noticeable in our coaches. Or, put another way, we're using very long
pulses. Note Hal's experience above.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[billvv]

I think the control algorithm would need to act slowly to avoid overshoot and maintain a water temp setpoint because the sensor that is sensing
engine heat load moves slowly, but the fan itself has to change speed quickly to make up for the loss of fan speed when the engine slows down.

One control that tries to maintain constant air mass through the radiator and another that changes the setpoint of the air mass control in reaction to
engine heat gain/loss.
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015.

 

[johnny]

Bill, if you or somebody is interested, get an arduino or the like for data gathering, and record temps, speeds, fan duty cycle, etc. Basically I'm
told the systems use a 20Hz pulse train width modulated. 20 Hz relative to the reaction speed of the valve and the fan is essentially a way of
turning the fan voltage up and down. It's cheaper than anything else. It would be interesting to hang your scope across the valve and see hoe
integrated the pulses actually are.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[billvv]

Johnny,
I think the PWM pulses turn the solenoid in the fan clutch on and off. The longer the pulse, the longer the solenoid is open, the more viscous fluid
is let through, the more the clutch is engaged and the closer fan speed is to engine speed.

I know that PWM control of electric fans basically change the average DC voltage to the motor and therefore change the fan speed. I don't think
viscous fans work that way.

--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015.

 

[johnny]

They turn the power to the solenoid on and off. It (the solenoid) opens and closes a valve to allow the working fluid into the vanes of the clutch.
It isn't capable of opening and closing 20 times per second although the voltage is appearing and disappearing at that rate. What happens is the
valve 'integrates' the pulses and essentially opens to a value equivalent to the average voltage of the pulse train. A switching transistor can
handle a lot more current that an amplifying one of the same size, thus the PWM controller is les expensioive to iterate than a voltage controller.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[johnny]

Before transistor radios (transmitters) pulse width modulation was popular. The transmitter integrated a 60 - 70KHz pulse train into an audio voltage
for the final amplifier. The intergration was done electrically rather than mechanically as in the fan clutch.


--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[Jim Hupy]

Solenoids are a long, long, wire of fairly small diameter. When a voltage
is applied to the wire, a very strong magnetic field is produced around
that coil of wire. If there is a plunger in the middle of the coil, usually
made of soft iron, it will try to get out of that strong magnetic field.
Repulsion induction is one name for the effect. Hook a lever or belcrank
onto the plunger, and you can do work. (Open a fluid valve, for example).
There is heat produced in the process, as well as a rapidly collapsing
magnetic field, and sometimes a high voltage of brief duration. RFI also is
produced. Not a friendly environment for electronic stuff like radio
receivers or on-board computers and the like. A viscous fluid coupling is
an imprecise device. Seems to me that there must be a better way to
regulate fan speed than this.
Jim Hupy
Salem, Or

On Mon, Feb 25, 2019, 6:42 AM Johnny Bridges via Gmclist <

> They turn the power to the solenoid on and off. It (the solenoid) opens
> and closes a valve to allow the working fluid into the vanes of the clutch.
> It isn't capable of opening and closing 20 times per second although the
> voltage is appearing and disappearing at that rate. What happens is the
> valve 'integrates' the pulses and essentially opens to a value equivalent
> to the average voltage of the pulse train. A switching transistor can
> handle a lot more current that an amplifying one of the same size, thus
> the PWM controller is les expensioive to iterate than a voltage controller.
>
> --johnny
> --
> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> "I forgive them all, save those who hurt the dogs. They must answer to me
> in hell" - ol Andy, paraphrased
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[johnny]

Let me suggest that in our coaches, I don't see it necessary anyhow. Turn the fan on or off as needed. IF you wish to run it at other than full on,
though, the cheapest and probably most reliable way is with a PWM system. As to solenoids and heat, the maker tells is it's built to remain on
constantly. I suspect in FedEx trucks in town it never turns off.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[billvv]

Johnny,
Aren't fuel injectors really solenoids? They open and close pretty darn quickly. But I can see how a PWM signal into a slow solenoid could pull the
solenoid towards open for the duration of a pulse, then relax, then pull again on the next pulse, and so on... thereby allowing a quantity of viscous
fluid through that is proportional to the duty cycle of the pulse train and to the average voltage as you describe.

Engine Control Units (ECUs) with EV Clutch speed control capability send out a PWM signal.

Here's video from Borg Warner showing how the EV clutch works.
https://www.youtube.com/watch?v=VxjfuJi4IUs
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015.