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-   -   good settings for afr/ego control (https://www.miataturbo.net/megasquirt-18/good-settings-afr-ego-control-70454/)

nwNAMiata 01-15-2013 01:22 AM

good settings for afr/ego control
 
Im curious as to what you all are running for settings in afr/ego, PID or Simple algorithm?
And then:
ign. events per step:
Controller auth %:
and if you suggest PID algorithm
proportional gain:
integral:
derivative:

I finally figured out that my massive afr fluctuation was due to my ego settings...so i turned it off and the wideband is steady, so now i want to see what settings are working the best

Loren 01-18-2013 06:02 PM

Okay, I'll chime in.

I'm using Simple, I think 3 ignition events (whatever the default was), and currently 30%.

I think if you had a big fluctuation going on and turning off EGO fixed it, that's probably an indication that your VE table needs to be tuned so that there's not such a big discrepancy between it and what the EGO is trying to do. OR... it could be that your O2 sensor isn't working correctly or configured correctly.

If you trust the O2 data, maybe try turning EGO back on, set the authority to something like 5%. Put a guage on your MT dash to show the EGO correction. That will at least show you what's going on. Is the EGO correction gauge pegged all the time? Go from there... you can give it more authority... or tune better... or both.

In the end, you want to have as little EGO correction happening as you can get away with. Like, if you rev and hold at 2k (or if you have EGO active at idle like I do...), your VE table should be correct enough that you have no more than a couple percent of correction.

With that, it really doesn't matter much (except for when something breaks) how much authority you give the EGO control. You could give it 50%, and if everything is tuned properly, it's only going to correct the 5-10% that it needs. But, if your O2 fails and tells MS that you're rich when you aren't... you wouldn't want it pulling 50% of your fuel. THAT is the purpose of the "authority" setting.

Once I'm done fiddling with "coarse tuning" where I have the authority set to 30%, I'll probably set it at 10 or 15%. Bear in mind that I'm NA... going 15% leaner than expected in the event of some sort of O2 system problem probably won't blow my engine up. On a high boost engine at high revs... maybe it could?

nwNAMiata 01-23-2013 03:19 PM

Thanks for the reply, i did turn my ego correction back on after getting my ve settings closer to the correct mark, and then i changed my spark event to 16 and the oscillation has stopped for the most part, usually runnning about 4% correction can someone chime in on what changing P, I and D do? thanks

albumleaf 01-23-2013 03:35 PM


Originally Posted by nwNAMiata (Post 971283)
Thanks for the reply, i did turn my ego correction back on after getting my ve settings closer to the correct mark, and then i changed my spark event to 16 and the oscillation has stopped for the most part, usually runnning about 4% correction can someone chime in on what changing P, I and D do? thanks

Learn to google.

PID controller - Wikipedia, the free encyclopedia

Braineack 01-23-2013 06:17 PM

3 ignition events is really low for EGO, that's not even a full cycles worth. I use 32.

Loren 01-24-2013 06:43 AM

You're right, 3 is low. I was going from (feeble) memory and guessed what it was. I just checked and it IS at 16 events. Like I said, whatever the default is. I never changed it.


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