feature request, pwm fan control

[krisr]

What would have to happen to get PWM added to the normal fan controls?

Lots of begging and pleading, unfortunately

[Matt Cramer]

One work around is to use a bitfield to activate an output when both the PWM output and the fan activation criteria are met. Or wire a regular relay, triggered by fan output, in series with a solid state relay controlling the duty cycle.

[Jamie V]

One work around is to use a bitfield to activate an output when both the PWM output and the fan activation criteria are met. Or wire a regular relay, triggered by fan output, in series with a solid state relay controlling the duty cycle.

First part of that would mean that the AC wouldn’t be able to turn the fan on unless ECT was high enough to trigger the fan also. Not good for the AC.

Second part of that would mean the fan wouldn’t be controlled with PWM.

What would have to happen to get PWM added to the normal fan controls?

Lots of begging and pleading, unfortunately

Who do I start begging to?

PWM is a feature that should 100% be in fan control (and not as a generic PWM).

I understand the need for a generic PWM for other uncommon things but controlling your cooling fans with PWM is not generic.

There should be an option in Fan Control for multiple fans, soft start, PWM for each fan independently, etc.

[dontz125]

Slight modification of what was discussed earlier, to replace 'PWM B' with 'AC => 100% DC'

Use two of the unpopulated outputs for the fan output and the PWM output; say, PK1 and PK3. You would then have the actual fan signal as a prog out coming on when [Portk] [AND} '10' Hyst '10'. The fan function turns on Port K bit 1 (=2) and the PWM function turns on Port K bit 3 (=8). If both bits are on (2+8=10), the output pin turns on and drives the fan controller.

Instead of looking at PWM B, look instead at Status 7 Bit 5 (=32); this is the 'AC = ON' bit. The function for your output channel is then:

[portk] [And] '10' '10'
[OR]
[status7] [And] '32' '32'

If you want two fans controlled separately, then you need a second output channel and a second PWM output; say, PWM B out put on PK7 (=128). The function for the second channel would then be:

[portk] [And] '130' '130'
[OR]
[status7] [And] '32' '32'


This allows normal, separate function of the 2 fans, as well as 100% operation when AC is engaged.

[Raymond_B]

I'm describing a workaround. There currently is no dedicated function that will PWM a fan while maintaining all other aspects of the Fan Control tab.

I understand that and am appreciative.

What would have to happen to get PWM added to the normal fan controls?

All, in order to make a correct request for this functionality (which it seems many want) is this first a firmware request from James and then a TunerStudio request from Phil? Or is it one or the other?

[dontz125]

There is no function to be added in TS. The firmware code has to be added by the devs, then the .ini modified by the devs to include the new function.

[Matt Cramer]

The settings that Don posted would activate the fan any time the fan activation criteria were met, as long as the PWM table had values at low tempertures to make the fan come on along with the A/C if you wanted it to run on a cold engine.

Wiring a solid state relay in series with a conventional one, likewise, would have the regular fan activation criteria decide if the fan should be off or on, and the PWM output decide how fast it should run.

[Jamie V]

Matt, i’m sure there are multiple ways we can use a walk around to make this work but the main purpose of this thread is to request that PWM be added to the fan controls.

Everyone helping each other find a way to make it work until then is wonderful but it sure would be nice if they could make the changes so that it was very easy to do for non-smart people like me.

[dontz125]

The only difference is that the relay method requires wired output pins, and wiring, and hard parts. Using the other-wise unused Port K pins reduces wiring and only needs a single hardware-equipped output pin (VVT, IDLE, etc).

[Jamie V]

The only difference is that the relay method requires wired output pins, and wiring, and hard parts. Using the other-wise unused Port K pins reduces wiring and only needs a single hardware-equipped output pin (VVT, IDLE, etc).

That’s what we’re after. My buddy Jeff is helping a bunch of us with this and his comment was

“Yeah I'm really surprised this functionality isn't in the system. All the pieces are there, just not connected.”

[wes kiser]

You may simply want to try the suggested methods/workoarounds. How frequently do you want/need fan at Max for AC, with no vehicle speed and a cool engine? While I understand the desire for real pen fan control and am not debating it, I think fundamentally a 40% ish minimum duty and and another pin functioning as the "enable" will work just fine. When it's relatively cool out the condenser doesn't need full flow. If the condenser is heating up, physically so is the engine. If engine heats up fan will spin faster. If it's hot outside the engine will heat up very quickly if stationary. If it doesn't the fan is oversized anyway relative to automotive AC needs. Certainly a "kluge" but physically I bet its a kluge that works well.

[Jamie V]

Wes, we are working on trying exactly what was suggested, and I’m sure with the help of everyone here we will be able to accomplish most of what we are trying to accomplish but I hope all this talk is demonstrating the need to add these features directly to fan control so all of these workarounds are not needed.

[Raymond_B]

As you guys have acknowledged, this is not a frivolous one off request. Hopefully James will weigh in and let us know if it's possible and if it is where it fits in his release schedule.

[Jamie V]

The fuel pumps options for PWM is similar to what I’m looking to add to fan control (ON/OFF or PWM).

But on top of that add Fan 2 (ON/OFF or PWM)

Have independent PWM tables for each of Fan 1, Fan 2 and Fan On With AC On. Fan 1’s load axis being the coolant temperature, Fan 2 and AC being able to select different load axis.

In my application I’d only use 1 Fan for now and I’d have it come on at 10% around 180° and ramp up to 100% around 200° the. Use the AC on option with a time based load axis and have it turn on at 10% and ramp up to 100% in 5-10 seconds.

It would shut off above 70% TPS and above 50 mph.

[Droppedf100]

Im just about finished with my pimpXshift install and would definitely be interested in pwm on the fan

[Droppedf100]

I’m with Jamie. I’d like the same thing and the easier to set up the better. I have a dual windstar fan set up and a pwm would be perfect as the fans work great but they hit hard on startup.

[vw_chuck]

I could use something like this when I switch my aircooled VW to electric fans for cooling. PWM would be mandatory for that setup.

[Dookie454]

Because the cooling fan options are so limited, I have to use Generic PWM A to PWM the cooling fan. This way I can slow the FAN way down when RPM is below 800rpm when alternator is not making much power, I use this on a plow truck that uses a 12v hydraulic motor lift the plow. Usually lifting the plow at idle or below idle, power draw is at a max so need to save power by slowing the fan.

Also I have it blend the fan on to full speed over 200deg coolant temp. Starts real slow, usually stays there unless it gets warmer, then comes on faster. No need for all the noise and wasted power for no reason.

As far as AC Fan control, OEM's usually monitor low or high side pressure.. as pressure increases then so should the FAN speed.

[Raymond_B]

@James, any thoughts on this? Is it something that can be done?

[wes kiser]

While I have personally never had a need to do this that couldn't be easily met as a generic PWM, it seams a large number of people really want this. A large percentage of people posting in this particular thread happen to have "our" plug and play.

While I see lots of people asking, I see very few identifying specifically what needs to be there. WIthout completely defining the feature, it is kinda hard for the developers to actually do it, as they have to guess, and then inevitably people will complain.

I propose the following:

1- Option to select fan type. If PWM is selected, then the following menus become active
2-Min Fan PWM %
3-Max Fan PWM %
4-Ramp to value time. Always starts at min duty, and ramps to commanded value over this time.
5-AC duty adder.
6-PWM table of fan duty verses coolant temperature. Should be no need for unusually high resolution, and can be 2d (duty verses coolant).
7-Typical PWM settings that go with generic table (frequency, pin, etc...)

Obviously if "AC duty Adder" plus table duty exceeds "Max Fan PWM %" then "Max Fan PWM %" is used instead.

Would the above cover everyone's requests? If not discuss. Don't just ask and expect someone to develop a feature that behaves as YOU want.