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Author Topic: Opinions: using KFLBTS vs LAMFA for fuel all the time?  (Read 351821 times)
masterj
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« Reply #90 on: December 06, 2011, 06:48:33 AM »

Well, I'll try to use KFLF map... Any suggestions on E85 AFR? (attached image)
« Last Edit: December 06, 2011, 06:54:09 AM by masterj » Logged

Rick
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« Reply #91 on: December 08, 2011, 11:54:25 AM »

KFLF won't help you if car is still in closed loop, you don't want to touch that.
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masterj
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« Reply #92 on: December 08, 2011, 01:33:41 PM »

KFLF won't help you if car is still in closed loop, you don't want to touch that.

And how can I force open loop instead? Which maps should I edit?

BTW: If car is in open loop does it still uses o2 sensor to reach target AFR?
« Last Edit: December 08, 2011, 01:35:39 PM by masterj » Logged

nyet
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« Reply #93 on: December 08, 2011, 01:39:09 PM »

BTW: If car is in open loop does it still uses o2 sensor to reach target AFR?

Not on a narrow band ECU like ME7
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phila_dot
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« Reply #94 on: December 08, 2011, 01:40:56 PM »

Can't you just raise the lean limit and target a leaner AFR?
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masterj
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« Reply #95 on: December 08, 2011, 01:42:48 PM »

BTW: If car is in open loop does it still uses o2 sensor to reach target AFR?

Not on a narrow band ECU like ME7

mine is ME7.5 and has wideband o2 sensor...
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masterj
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« Reply #96 on: December 08, 2011, 01:43:49 PM »

Can't you just raise the lean limit and target a leaner AFR?

that's what I was thinking... just change target AFR and o2 sensor should adjust automatically to it... But Rick said that it's a no no
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phila_dot
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« Reply #97 on: December 08, 2011, 01:54:27 PM »

Can't you just raise the lean limit and target a leaner AFR?

that's what I was thinking... just change target AFR and o2 sensor should adjust automatically to it... But Rick said that it's a no no

The lean limit is lambda 1 by default. Lamlgfmn needs to be raised to allow a leaner mixture.

Edit: i wouldn't adjust kflf though.
« Last Edit: December 08, 2011, 01:56:01 PM by phila_dot » Logged
masterj
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« Reply #98 on: December 08, 2011, 01:58:13 PM »

Can't you just raise the lean limit and target a leaner AFR?

that's what I was thinking... just change target AFR and o2 sensor should adjust automatically to it... But Rick said that it's a no no

The lean limit is lambda 1 by default. Lamlgfmn needs to be raised to allow a leaner mixture.

Edit: i wouldn't adjust kflf though.

thanks Smiley if not KFLF then which map would you suggest to control target AFR?

Btw: maybe you know address/factor of Lamlgfmn on m box, so I could compare it to my bin?
« Last Edit: December 08, 2011, 02:00:25 PM by masterj » Logged

phila_dot
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« Reply #99 on: December 08, 2011, 04:10:58 PM »

Can't you just raise the lean limit and target a leaner AFR?

that's what I was thinking... just change target AFR and o2 sensor should adjust automatically to it... But Rick said that it's a no no

The lean limit is lambda 1 by default. Lamlgfmn needs to be raised to allow a leaner mixture.

Edit: i wouldn't adjust kflf though.

thanks Smiley if not KFLF then which map would you suggest to control target AFR?

Btw: maybe you know address/factor of Lamlgfmn on m box, so I could compare it to my bin?

It should be map LAMLGF or something along those lines. I'll look it up when I get home. Lean target lambda is the hard part as LAMSEL is set up to always follow the minimum/richest path and LAMDSK is hardcoded Lambda 1 by default.

Edit: Lambda lean limit is LAMLGMTM at 18CC0 factor 0.007813 and axis 1014B degrees celcius factor 0.75 offset -48. Stock is 1.093.

I don't think it will help though.
« Last Edit: December 08, 2011, 07:27:16 PM by phila_dot » Logged
s5fourdoor
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« Reply #100 on: December 10, 2011, 06:22:28 PM »

Hey Guys - i've been following this thread for a while and I'm not sure about alot of things here.

The stock DLBTS has a % that ranges from 4 to 17.  Surely this can't be that relevant right?  The values taken by the table are all negative, implying that when multiplied by KFFDLBTS - where the values are all positive, we'd see a decreasing of the KFLBTS target.  In other words, with everything stock, when the EGT model goes above TABGBTS, there is targeted richening of the mixture.
This obviously makes intuitive sense.

The question is why does the DLBTS axis go from 4% to 17%?  That seems like an irrelevant axis...  Does anyone else agree with this?  Why is this?

Here's the thing.  Everybody here seems to be talking about using KFLBTS as an actual functional target axis.  If this is true, we aren't using this table AT ALL like it was intended.  We are using it rather to distinguish between casual driving and high load driving, not normal driving and emergency conditions - as Audi used this originally.  Therefore we need a discussion about what needs to be done with the associated tables.

Here's my point of view on it.  KFLBTS should be a target AFR, and the additive tables (KFFDLBTS and DLBTS) should be zeroed out.  Input please...

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Rick
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« Reply #101 on: December 10, 2011, 07:18:18 PM »

I really think you have confused yourself.  There are 101 ways in which to work the fuelling, choose and calibrate a method that you think is right. 

Rick
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phila_dot
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« Reply #102 on: December 11, 2011, 04:40:21 PM »

Hey Guys - i've been following this thread for a while and I'm not sure about alot of things here.

The stock DLBTS has a % that ranges from 4 to 17.  Surely this can't be that relevant right?  The values taken by the table are all negative, implying that when multiplied by KFFDLBTS - where the values are all positive, we'd see a decreasing of the KFLBTS target.  In other words, with everything stock, when the EGT model goes above TABGBTS, there is targeted richening of the mixture.
This obviously makes intuitive sense.

The question is why does the DLBTS axis go from 4% to 17%?  That seems like an irrelevant axis...  Does anyone else agree with this?  Why is this?

Here's the thing.  Everybody here seems to be talking about using KFLBTS as an actual functional target axis.  If this is true, we aren't using this table AT ALL like it was intended.  We are using it rather to distinguish between casual driving and high load driving, not normal driving and emergency conditions - as Audi used this originally.  Therefore we need a discussion about what needs to be done with the associated tables.

Here's my point of view on it.  KFLBTS should be a target AFR, and the additive tables (KFFDLBTS and DLBTS) should be zeroed out.  Input please...



lambts provides enrichment to combat rising EGT's. dlambts is an additive to lambts to provide further enrichment for a severely degraded ignition angle up top.

Why would you want to disable this function?

The axis is correct. The input for DLBTS, delta ignition angle efficiency detazwbs typical values are ~0 if zwist equals zwbas and retard is near zero. detazwbs is % of ignition angle effectiveness (zwopt-zwgru) - % of ignition angle effectiveness(zwopt-zwist). Only torque intervention or high retard will activate it. It is also a multiplier for KFFDLBTS which is zero everywhere but up top.
« Last Edit: December 11, 2011, 05:38:05 PM by phila_dot » Logged
s5fourdoor
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« Reply #103 on: December 23, 2011, 02:38:33 PM »

OK.  Thanks for that clarification.  Very insightful.  There's effectively no reason to turn off this inherent safety feature regardless of how you tune LAMBTS.  I understand this now, thanks.

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TTQS
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« Reply #104 on: January 01, 2012, 06:53:35 AM »

I did a quick log with ME7logger yesterday during which I spend a good length of time at 100% mrfa_w to generate EGTs up to 933°C. lambts_w was unity all the time (presumably because the threshold temperatures are 950°C so LAMBTS is never active) and LAMFA reduced steadily from 1 to 0.89 (approximately "lean best torque at WOT") along the 100% mrfa_w line as nmot rose from 2,000 to 6,000.

http://nefariousmotorsports.com/forum/index.php/topic,1296.msg12400.html#msg12400

However, something more subtle is happening because desired lambda (lamsbg_w) and actual lambda (lamsoni_w) decrease well below 0.89 to around 0.75 (approximately "rich best torque at WOT") as EGTs rise above 900°C.

As Rick says, there are many and varied ways to achieve the same result. Before I discovered this, my personal prejudice was that using LAMFA for high load enrichment was perhaps crude way of getting out of tuning LAMBTS. This prejudice on my part arises, I think, from a comment a professional tuner made to me which I paraphrase as "I'm not going to reveal how I tune WOT AFR because many people don't understand the subtleties of LAMBTS".

All good fun.  Cheesy

TTQS
« Last Edit: February 07, 2012, 10:07:09 AM by TTQS » Logged
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