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Author Topic: ME7.9.10 - Understanding the torque model  (Read 177404 times)
woj
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« Reply #270 on: August 30, 2018, 05:59:16 AM »

Thank you! That's more than I need and it actually confirmed what I wanted to check (that the last part from raw 680 on is unused, properly). Plus one other small thing Wink
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woj
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« Reply #271 on: September 22, 2018, 07:41:06 AM »

I am still playing with E85, and now the weather got substantially colder (still not freezing or anything). My cranking is working fine so far, but I also noticed uneven AFR figures during the first minute of driving (maybe not even a whole minute). Is my conclusion that the wall wetting maps need some attention for E85 on the colder side correct?

EDIT: After careful analysis of my logs from this morning the question turns out to be rather rhetorical. The one that should be asked is by what order of magnitude I should modify KFBAKL/KFVAKL?
« Last Edit: September 22, 2018, 12:51:47 PM by woj » Logged
Assoor
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« Reply #272 on: September 23, 2018, 12:33:04 AM »

i believe Ethanol always needs 60% more fueling than Gasoline. so i believe you can add 50% will be good for E85
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woj
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« Reply #273 on: September 23, 2018, 03:12:56 AM »

Not 60 for Ethanol, less, and precisely 43% for E85 in my case, but that's not what I asked :/

Interestingly, increasing KFBAKL / KFVAKL made things worse, my test area was 20 deg C. Will try with less, but the car needs to cool and it will be in use for the rest of the day. The other problem is a horrible lag in my AFR readings, makes log analysis very difficult.
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woj
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« Reply #274 on: September 24, 2018, 12:38:35 AM »

I am a getting a bit confused with the semantics of KFVAKL - do bigger values mean more fuel / lower AFR? It seems it's the case, but it is sort of counter-intuitive, because the map name in "enleanment"...

EDIT: The code, from what I see, says "the bigger KFVAKL value to more fuel subtracted on deceleration". So my intuition was correct, but that also means something weird is going on in my engine.

EDIT2: Reading further threads on the issue and also looking at my logs it is more or less clear that (a) the increase in enleanment needs to substantial, contrary to enrichment which most people report as more or less OK (which I cannot fully agree with, but enleanment seems to more crucial), (b) this needs to be done through the whole or almost whole operation range, not only for cold. My logs seem to confirm point (b) too.

All in all it sounds like I'll have to make a couple of test drives with lambda control fully disabled until I get the numbers right.
« Last Edit: September 24, 2018, 11:42:02 AM by woj » Logged
pc1010
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« Reply #275 on: September 28, 2018, 05:16:28 AM »

Regarding logs I'd like to ask how do you log EGT? MultiEcuScan shows the parameter empty and says it's not possible. Is it related to SW version?
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IamwhoIam
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« Reply #276 on: September 28, 2018, 06:05:45 AM »

Regarding logs I'd like to ask how do you log EGT? MultiEcuScan shows the parameter empty and says it's not possible. Is it related to SW version?

Ideally you want a real thermocouple in the exhaust manifold, just before the turbine, EGT model values that you log from the ECU could be totally wrong vs the reality.
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I have no logs because I have a boost gauge (makes things easier)
woj
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« Reply #277 on: September 28, 2018, 06:14:44 AM »

Regarding logs I'd like to ask how do you log EGT? MultiEcuScan shows the parameter empty and says it's not possible. Is it related to SW version?

Most probably, I have never looked at EGT variables carefully, but I have seen other variables disabled in bins, even though the docs I have seen suggest they should give a reading.

BTW, following the other comment, I log EGT only to have the logging of it ready later when I get the actual EGT logged too to be able to see how (un)faithful the EGT model is. Just looking at the values I get and from previous experience with FIRE engines they seem about right, but this "about" can be actually off by over 50 degrees, which does make a difference.
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pc1010
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« Reply #278 on: September 28, 2018, 06:50:36 AM »

That's too bad. I wanted to check the EGT the ECU calculates internally because my car always follows the KFLBTS maps for fuelling. Now I run about 0.75-0.8 lambda at WOT with LAMFA but it drops nearly instantly to about 0.7 like in BTS maps.
Is there an option to enable it?
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woj
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« Reply #279 on: September 28, 2018, 07:04:21 AM »

LBTS might be one reason (and would be, but you can always edit LBTS to suit your AFR needs), but the other problems are notorious ignition retards on these setups which imply further enrichments. These you can also edit out in the LAMBTS module. And what's wrong with LBTS setting your fueling?
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pc1010
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« Reply #280 on: September 28, 2018, 10:03:45 AM »

For now I did just like you said. I have edited KFLBTS to 0.8-0.75 from 0.69-0.75 because in my opinion it was just too rich.
The reason I wanted to ride on LAMFA was just to go leaner and in case of high EGT to switch to richer AFR just to cool down. Another thing was that this map could take maximum of 191% of load and that spoils precision a little.
Do you think that it's OK to just ignore it and tune my AFR just for KFLBTS? I heard that these engines run too lean so that would be the reason for cracking headers and turbos and I just leaned the BTS map so this could be dangerous? What is your opinion?
Also there isn't option to log retard events, I just have to watch on values to assume retard?
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woj
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« Reply #281 on: September 28, 2018, 12:19:17 PM »

I think in the default setup this ECU runs mostly on KFLBTS. There is a delay on applying LAMFA (some ECUs 1s, some whole 5s!), which effectively means that KFLBTS will dictate the AFR before you know it. Following the description on the S4 wiki, LAMFA is mostly for preemptive fueling, which effectively means lower rpms and that only if you kill the delay sufficiently. Then it's all KFLBTS. So tune both to your AFR needs. 191% RL limit is not a problem IMO, this is ~1.2bar, at that point you should already be max rich and keep that way for higher boosts.

Who said these engines run lean? I am not accusing anyone of false claims, it's just that I think they are horribly rich, but I only personally dealt with one t-jet. But I did run a self turboed 8V FIRE engine before (successfully for several years and over 60kkm), and my lowest AFRs at 0.8-1bar boost were 11.8-11.5. The trick though was that the AFR table was fully static and conservative otherwise, 13.5AFR already is small vacuum, 12.5 AFR entering boost from 3000 RPM up, no BTS or WOT differentiation shit. Well, OK, admittedly the engine also had much lower CR than t-jet, but in any case it run absolutely sweet. The reason for cracking headers I heard of is simply a factory mistake in making it a fully solid design. Interestingly, mine is very likely cracked too, but I never had a chance to check, and I am far too lazy to replace it when there are no ill signs.

As for the retards, you are a second person saying they are not loggable, this should answer your first EGT question again - software differences. On my high resolution logs I first noticed retards because my actual torque figure was very spiked, this is the result of aggressively varying ignition between cylinders. You could try logging zwout and see if it's spiked and how far it is from your expectations from the tune. But in any case, you are guaranteed to have knock retards, so bad sometimes that the fuel goes insanely rich (I have seen 9.5 on my gauge a couple of times). You can try to kill it by editing DLBTS (I have seen people doing this).
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pc1010
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« Reply #282 on: September 28, 2018, 01:30:58 PM »

So I'm still running too rich? Wink What you said about DLBTS could be cure for my problems with alternative fuel. When on PB98 the car runs quite good but on LPG I'm getting ignition retards with overfuelling that much it is looping injectors. Don't know why if LPG has over 100 octan rating. All setting for LPG I did using STFT on Closed Loop and AFR on Open Loop, just little leaner than noPB.
That's too bad I can't log retards and EGT, I know it's crazy idea but isn't it possible to update/change software to other version? I know it was sometimes possible with older ECUs but there I think it's not.
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woj
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« Reply #283 on: September 28, 2018, 02:07:24 PM »

To know if you run rich or not you'd have to have the real EGT connected I think, the figures I gave were just an example for essentially a different engine.

LPG... that would have to have a piggy back system of some sort, no? Could that be a problem, I mean its setup?

There are some issues swapping software in these ECUs. The software in general is swappable as far as the ECU itself is concerned (well, EEPROM size might be an issue, they came in two sizes), but the versioning spreads to the other ECUs too, CAN IDs in particular can be different. But, the logging interface has a configuration block in the data area, EGT and retards could be added, the only problem is it would require a small amount of disassembly work to find the block and variable addresses...

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pc1010
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« Reply #284 on: September 28, 2018, 02:36:39 PM »

So as for now that is not possible I see...
When it comes to LPG the injection system has its own MAP sensor, RPM and temperature sensors. It gets injection timing from ECU outputs and the LPG injectors have their time scaled by a factor depending on engine load, gas pressure, temperature, etc. Generally it works very well, power is nearly the same as on petrol just when mashing the pedal there is jerking. I am 100% sure it's not LPG system because the pressure is stable on all loads and AFR was set in 3D table to correspond to the petrol ones, just like I said earlier they are leaner because rich LPG mixture isn't too good for engine and especially not for cooling. I couldn't log ME7 that fast to see this phenomenon on log so I can only assume that this could be petrol injectors looping or strong ignition retard.
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