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Engine fan control


Ivaylo Angelov

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Hello all and Happy New Year!

Please, I need an advice how to switch ON and OFF the engine fan based on two different temperatures. The fan is located behind two radiator cores, sealed inbetween. The front core is for the air-water intercooler system. The rear core is the engine  cooling radiator.  So, my aim is to switch ON the fan based on the ECT and also on the IC coolant temperature (there is a dedicated temp sensor connected and calibrated to AN volt 8 input).  

So far checked the engine fan AUX output as GP Output with logic cond 1 OR 2 (Cond 1 is ECT. Cond 2 is AN Volt8) and it seems it should work OK. What bothers me is that for GP Output there is no temperature hysteresis value but only a switch OFF timer delay value with max 12s only! That means if any of the temeratures falls slowly, the fan will be switched OFF (after 12s) but the actual coolant teperature drop could be just 2-3 C !?

Is there another way or logic for the engine fan control so I could achieve my aim but using OFF Hysteresis temperature  for both values?

Can I connect another! AUX Out to the same Fan relay pin as the "Engine Fan" Aux Output, so the Fan relay will receive ground signal from two independent Aux Outputs? What function to choose for the other AUX Out?

It is G4 Xtreme Red ecu.

Thank you!

Ivo

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Think this should work:

Setup 2 Virtual Aux

Virtual Aux 1

Logic = Cond(1 AND 2) OR 3

SW Cond 1 ECT | > 55

SW Cond 2  | Aux Virtual Value1 = ON  | 1

SW Cond 3 | ECT > | 75

Virtual Aux 2

Logic = Cond(1 AND 2) OR 3

SW Cond 1 IAT | > 35

SW Cond 2  | Aux Virtual Value1 = ON  | 2

SW Cond 3 | IAT > | 50

Then setup a AUX as a GP output 

Switch Logic Cond 1 OR 2

SW Cond 1 Aux Virtual Value1 = ON | 1

SW Cond 2 Aux Virtual Value1 = ON | 2

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26 minutes ago, Ivaylo Angelov said:

Thank you Clint! I'll try these settings.

It seems though, there is no support for G4 since New Year !??? I hope this wont be "forever"...

Support was closed till the 8th of Jan so are probably a little backlogged.

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OK,

Here are my new settings:

Virtual Aux 1 as a GP Output:

Virtual Aux 1.bmp

Virtual Aux 2 (for the intercooler coolant temperature) as a GP Out:

Virtual Aux 2.bmp

and the FAN control Aux Output set as a GP Out:

Fan control Aux as a GP Out.bmp

I understand your logic and it corresponds to the examples given in the Help menu. What bothers me is the Fan's GP Output setup. Why SW Cond 2 is again "Aux Virtual Value 1=ON" ? (Actually there is no other choise but "Aux Virtual Value 1=ON"  in the "SW Cond" menu!?) What, where from are the values 135 and 75 on the attached screenshot (Fan ctrl as a GP Out)? I didn't put them there.

What do you think?

Thanks!

Ivo

PS:  Aha! OK!  You!!!!  have adopted  "1" and "2" as Aux Virtual VALUES! for SW Cond 1 and SW Cond 2 ? Does that distinguish for sure betveen Virtual Aux 1 Out and Virt. Aux 2 Out  in the Fan Control GPOut setup?

SW Cond 1 Aux Virtual Value1 = ON | 1

SW Cond 2 Aux Virtual Value1 = ON | 2

;)

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21 hours ago, ClintBHP said:

On Aux 1 you have a mistake you need to reference the same Aux in the second condition.

Hi Clint,

OK, but when I'm setting the SW Cond2 for Virtual Aux 1-GP Output, there is avaiable only "Aux Virtual value 2=ON (OFF)" from the pull-down menu? It seems I have to use for SW Cond 1 the Virt.Aux1 own on/off state. Only then the pull-down menu offers "Aux Virtual value 1=ON (OFF)".

...Or I'm totally out of space?:(

Please, would you check this again for me?

Thank you!

 

 

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Thank you vey much Clint!

No , it is not tested yet because I have to brake in the engine first. I could try it with variable resistors on the temp. sensor connectors.

It would be great if someone of the Link support could confirm these Fan control settings.

Thanks again. Will give a feedback when tested.

Ivo

 

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  • 9 months later...

Hi, 

Unfortunately it is not fully tested yet. The car is in a body preparation period, so no more engine starts lately. I did test these fan settings once though. The fan turned on as expected on the set engine coolant temperature. I  had not enuogh time to  play with the IC water temperature settings to trigger the fan.

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  • 2 years later...

Hello all!

The work on the car was postponed for a long time. Just recently the engine was started again and... here is the thread revival. I need help though:(The problem I'm facing is with the idle rpm control.  My radiator fan is switching ON and OFF as per the control logic described above. So far so good but when it turns ON the idle rpms sink down remarkably due to the initial generator el. load. Tried to add ms fuel and % PWM idle valve corrections when the fan kicks in but without success. Then I realized that these idle rpm corrections/compensations might work only when the output is configured as "Engine Fan" . This is not the case with my current Fan control output that is configured as "GP Output" so I could implement the logic. If that's correct, how could I add the same idle control corrections when a "GP" Output controls the engine fan?

Thanks!

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Hello Adam,

Unfortunately I forgot to take a log from the moment of idle rpms sink. I'll do that when I get back to the car. Here is my pcl file. The fan is wired to AUX 7.  Again, what I can read in the Help Manual,  G4 ECU Tuning Functions>Fuel>Idle Load Trims is related only about when "Engine Fan" output is activated.  The same is with the Idle speed control settings and the "Engine Fan Step".

Thank you!

050921.pcl

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G4 is a bit limited in this respect.  There are no user definable "idle steps".

The best work around that I see is to loop a wire from your Aux 5 fan output to a spare DI.  Set the DI up as power steer switch.  Then you can use the power steer idle step and power steer idle load fuel trim for the fan.

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On 9/11/2021 at 1:54 AM, Adamw said:

G4 is a bit limited in this respect.  There are no user definable "idle steps".

The best work around that I see is to loop a wire from your Aux 5 fan output to a spare DI.  Set the DI up as power steer switch.  Then you can use the power steer idle step and power steer idle load fuel trim for the fan.

Strange,  there is no Idle Load Fuel trim for the Power Steer. There is just Air ConTrim, Engine Fan trim and Drive trim. Anyway, I'll configure the DI as an Air Con Request

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