Wideband closed loop and AFR targets

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Wideband closed loop and AFR targets

Postby 34blazer » Tue Mar 05, 2019 11:20 am

TL;DR: I'm exploring the possibility of using the 0-5v output from my wideband as the input for closed loop fuel control.

I'd like to split the signal from the wideband or even just use that as the primary input and convert the add definition as needed. Looking at the conversion, it's expressed as x/230. Quick math indicates x/51 to convert the xdf definition to display a 0-5v range. But that's only part of it. I'd like to know if it's possible to get some guidance to change the conversion in the code to use that 0-5v signal as part of the calculations. I seem to grasp the concept if I can reverse engineer the procedure rather than comb through a hac and guess.


There's a flag called "Map A: set= A/F check for closed loop fuel logic", what is that for? Does it check the AFR target tables or something?

Also, when in PE mode will the BLMs lock at 128?

Thanks
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Re: Wideband closed loop and AFR targets

Postby vlad01 » Tue Mar 05, 2019 3:20 pm

Closed loop uses the narrow band input. Most good WB sensors have a simulated NB output. I would just use that. I do on mine and it works great.

You can use VE learn mode to directly auto adjust the VE table on the fly. I have also used that feature with good success. That mode uses the existing WB input and no need for special setups.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.

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Re: Wideband closed loop and AFR targets

Postby 34blazer » Wed Mar 06, 2019 1:17 pm

Oh I know it is NB feedback, I'm just exploring the road to using wideband closed loop for emissions reasons.

I don't have an NVRAM so I can't use VE learn.

My AEM 3110 should be able to produce a 0-1v output but I'm worried about resolution and the possible negative effects.

I used CL with wideband feedback with code 59, but I found that the BLMs didn't lock at 128 during PE. Junkclr modified 8D to use Wideband feedback and had some great results.
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Re: Wideband closed loop and AFR targets

Postby 34blazer » Wed Mar 06, 2019 2:43 pm

So I was just thinking......

12P already has a wideband patch for wideband VE learn with the NVRAM, and it already has the scale defined for 0-5v. So basically the NB current value is stored as part of the equation, and what if I can use the value for the WB instead. And as long as I can find the scalers and change the equation to use 0-5v then I think that will work. Unless those scalers use a lookup table as well? Then it would be a matter of redirecting them to use the WB lookup table?
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Re: Wideband closed loop and AFR targets

Postby 34blazer » Fri Mar 08, 2019 4:02 pm

Bump?
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Re: Wideband closed loop and AFR targets

Postby Dylan » Fri Mar 08, 2019 4:12 pm

Hi mate, I haven't read your whole posts. It's good to see your jumping to 12P.

Not to sound rude but I'm wondering if you're making it harder than it needs to be? The VE learning is a great feature but it's far from auto tune. Tick the flag for open loop and tune from logs with wide band connected to the ECU.
Post the logs up and I'd be more than glad to help you along.

I look forward to your progress.

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Re: Wideband closed loop and AFR targets

Postby 34blazer » Fri Mar 08, 2019 10:27 pm

I thought I need NVRAM for that? I don't have NVRAM, rather the Ostrich 2.0 :(

Thanks Dylan!
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Re: Wideband closed loop and AFR targets

Postby Dylan » Sat Mar 09, 2019 7:48 am

You can still data log with wideband without an nvram board.
Wire in wideband. Set the 0 5 volt scalers to get readings correct and start logging. Then adjust VE table after reviewing the logs.

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Re: Wideband closed loop and AFR targets

Postby 34blazer » Sat Mar 09, 2019 11:13 am

Yes, that's what I've been doing. Just wanted a wideband closed loop option.
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Re: Wideband closed loop and AFR targets

Postby Dylan » Sat Mar 09, 2019 11:19 am

Post up a log with a matching bin. I'll have a look over.

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