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Author Topic: ME7.9.10 - Understanding the torque model  (Read 48128 times)
guyst
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« on: June 05, 2016, 05:42:17 PM »

Hi to all (my 1st real question/subject..)

Im currently struggling to understand my fiat bravo tjet 1.4 torque model. I found many relevant maps using a damos of an alfa mito 135 (same Tjet motor) - torque, ignition and lambda related. main maps for torque at WOT:

KFPED Torque requirement from pedal
KFMIRL Load from required torque
KFMIOP Optimum torque from load
KLMIMAX Characteristic maximum indicated torque
KFMDBGRK Max torque for clutch protection
MDMAXNMOT Max indicated Trq for power limit

I couldnt find any map relating max load like LDRXN or KFLDHBN, only torque limiters, so it seems this ECU has a different torque model than ME7? (Based on torque and not load i guess). This means i cant use the strategy you people use on the ME7 - although there seem to be some similarities.
As of now I tried raising the torque limiters and got the boost up to 1.25 at low revs, but it lowers down to stock 0.8-0.9 by 3500-4000RPM. The requested torque seems to be high enough (not by logging).
I also measured WGDC and its at 55-60% at 4000RPM, so I dont think its a hardware issue.

My first aim is to raise boost to ~1.3 Bar and make a flat and wide as possible torque curve. After addressing that ill take care of the fueling and ignition.
I would very much appreciate any help at understanding the torque model of the ME7.9.10 as there is absolutely no info on the web...
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woj
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« Reply #1 on: October 21, 2016, 11:53:54 AM »

Hi,

Can't really give you a straight answer, and I am also not a very active member of this forum (any questions I had so far were not answered). But at least you get a friendly soul, because I also try to understand the workings of this ECU and I studied the same WinOLS definition as you did I believe (there is only one out there). And I was also looking for corresponding maps in other bins to compare.

First thing to note, this ME7.9.10 definition has unfortunately mistakes, so you have to take everything you see there with a grain of salt.

Second, yes, to me it also seems that raising MDMAXNMOT should do the trick in most part. (BTW, I do own a 120 hp t-jet, but I am nowhere near being able to play with it live), but there is a couple of other torque and pressure watchers and limiters that may interfere with this. And yes, there is no maps similar to ones mentioned here a lot for the older ME-s.

If I come up with a good candidate what blocks your boost at higher revs I will let you know here. But in the meantime you could try to share your findings since June Wink

Cheers
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Rick
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« Reply #2 on: October 22, 2016, 05:33:27 PM »

Torque managed ECU instead of load managed ECU.
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woj
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« Reply #3 on: October 25, 2016, 12:00:02 PM »

Torque managed ECU instead of load managed ECU.

If I may ask politely - what does this answer bring to the subject? This is already given in the title. The question of the OP is very valid, because this ECU is newer than the commonly known ME 7.1 / 7.3 around here, it is similar to MED9, but in many ways different, and in particular in the fact there is *really no load* in a sense - Fiat chose in most of their gasoline engines not to employ a MAF, so this ECU is based solely on two MAP sensors on the two sides of the throttle for load estimation. And a very detailed intake manifold and valve duration model.

One Mr. Revlimit a.k.a. hammersword known on another forum (perhaps he is around here too) tries to convince everybody that this ECU is very complex, and in a way he might be right - the factory maps and parameters that upgrade the 155hp version of Fiat Grande Punto to the 180hp Abarth go way over 400 items. On the other hand, looking at the map definitions and comparing it to the available ME documents, the general principle of this ECU and basic tuning does not seem to be that complex as the above mentioned person would try to make you believe. I think he just might be protecting his business.

In any case, there is little information about this ECU out there we are trying to get the basic understanding of how this particular ECU differs from the better known ME instances, and where the fine points are. Yes, we know it is torque model kind Wink
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prj
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« Reply #4 on: October 26, 2016, 12:25:31 AM »

If I may ask politely - what does this answer bring to the subject? This is already given in the title. The question of the OP is very valid, because this ECU is newer than the commonly known ME 7.1 / 7.3 around here, it is similar to MED9, but in many ways different, and in particular in the fact there is *really no load* in a sense
You do not understand ME7.

To elaborate:
All ME7 goes from pressure to load. It is a speed density ECU by nature.
If it runs MAF it calculates the pressure in the manifold from the MAF reading, if it runs MAP it takes the pressure direct from the manifold.

The same VE maps are present in all ECU's. In case of MAF it uses the VE maps to go to pressure and then the same VE maps to go back to load.
Meaning even if you calibrate them wrong it won't change much.

Do some reading on BGSRM and other things.

As for limiting load, nothing special - LDRXN is just torque based, not load based, and called differently, that's all there is to it.
As for a certain person writing on every forum that everything is complicated - well it is just PR to build some kind of image. In reality there are many competent people capable of tuning these ECU's and he is nothing special.
« Last Edit: October 26, 2016, 12:27:42 AM by prj » Logged
woj
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« Reply #5 on: October 26, 2016, 01:56:49 AM »

I am quite sure that I understand it more than you think Wink I only probably do not explain myself so well, I tend to get problems of building things in my head in a different way than others.

Yes, I got the part where pressure is converted to load and vice versa, my impression so far was that this is to be able to establish how much air pumping from the turbo should be there, because pressure is the only controllable thing on a turbo. As for the load, it is indeed "fake" in a way, and from what I see mostly used as an intermediate index to other tables. The actual load getting into the cylinders is calculated in the BGLWM module (which BTW is not present in the MED, probably there is a counter part of some sort). But then, there is BGRLP module for predicted load that calculates mass flow depending on throttle angle and pressure delta across the throttle. Probably has nothing to do with the the actual load calculation (does it?), but it so much different in two versions of the same factory program for this ECU, that it has to have some serious influence on something somewhere. These are the kind of things that I want to understand, and I am not there yet.

This ECU has no BGSRM, but I looked it up briefly in MED and I see what you are getting at. The module that this is mentioned in is BGFKMS and the only thing that changes in this module in this ECU is the total mass-flow leakage parameter MSLG, everything else stays the same on all engine / turbo versions in the factory calibrations.

Yes, there is a counterpart of LDRXN, I believe this is the MDMAXNMOT that the OP mentioned. But for him something else limited the boost / torque, and it is really not obvious what. (For me might as well be the calculated EGT). Yes, I know, to find out things should be logged and analysed. I am not yet at the stage of being ready to play with my engine, and the OP seems not to want to share / participate anymore Wink

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prj
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« Reply #6 on: October 26, 2016, 03:05:24 AM »

Yes, I got the part where pressure is converted to load and vice versa, my impression so far was that this is to be able to establish how much air pumping from the turbo should be there
Nothing to do with turbo.
Quote
As for the load, it is indeed "fake" in a way
Load is no more real or fake than the engine is. It is air charge in cylinder, what's so hard to understand? Whether you measure it directly with the MAF or you calculate it based on measured pressure bears no relevance to the ECU. rkte, more precisely rk_w is calculated from load.

Your entire wall of text is wrong.

Had a quick look - BGLWM has the VE maps to go from pressure to load, just as BGSRM does on other ECU's. KFFKUPRLLB, KFFKUPRLMX are multiplicative corrections, KFFKPBRRES, KFFPBR additive.
BGRLP is transient compensation, turned off on many ECU's because ESUK is sufficient.

Took me literally one glance to tell you that, without walls of text.

MDRLMX replaces LDRLMX, it is simply a compile time option to use one or the other. Same for MED9.
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woj
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« Reply #7 on: October 26, 2016, 04:58:04 AM »

I will look into this, some things still bother me about this - if the two factors are additive, then there I need to look up exactly what is going on there, because in the map definition that I have they certainly look like a multiplicative factor (probably they multiply some something additive first), I know that the mult one works directly on fupsrl.

This does sound simple, but then what are all the maps like turbine and compressor efficiency used for, or cam shaft duration? These are all calibrated between the different engine setups (the bare engine being the same, differing only in cams and turbos) and the total amount of these things goes to over 400 items in factory calibrations. What I am after is understanding which ones are crucial, which ones are not, for DIY tune.

MDRLMX looks simple enough but it surely is not the only thing that controls the end torque / load / boost. For one, there is a map that limits the compression ratio of the turbo to maintain low enough charge temperature. These the kind of "small things" I am after understanding Wink
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prj
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« Reply #8 on: October 26, 2016, 12:48:14 PM »

This does sound simple, but then what are all the maps like turbine and compressor efficiency used for, or cam shaft duration? These are all calibrated between the different engine setups (the bare engine being the same, differing only in cams and turbos) and the total amount of these things goes to over 400 items in factory calibrations. What I am after is understanding which ones are crucial, which ones are not, for DIY tune.
They are not used in calculating load from pressure.
Quote
For one, there is a map that limits the compression ratio of the turbo to maintain low enough charge temperature. These the kind of "small things" I am after understanding Wink
Just like it is in every single ME7.

I know all this, because I have tuned all of these ECU's, also the ME17 that is on those cars.

I just think that the spoon I'm feeding you with is big enough already, might be good if you went through it on your own Tongue
The FR will help. Also walls of text about how you think things work is worthless. Things work only one certain way - the way the code is in the ECU. Look it up in the FR. If you don't have FR, disassemble. That's how I do it.
« Last Edit: October 26, 2016, 12:50:27 PM by prj » Logged
woj
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« Reply #9 on: October 26, 2016, 01:45:17 PM »

I really appreciate the spoon Wink And believe me, I do spend time on this, and it is not the first ECU I am studying, previous studies went flawless, but admittedly these were much simpler ECUs (but without documentation whatsoever). But now there are lots of obstacles, severe lack of time for starters, poor knowledge of German is the other (yes, I know there are and I have seen the translations of the crucial modules). And last couple of months I spent solely on matching the maps in the different bins that I have based on a definition for just one that is out there. I only got back on FR reading last couple of days once having all the maps I want to look at in place and in the only program I know how to use efficiently, TunerPro that is, written up a TP checksum plugin for this ECU, these kinds of things. Getting back on FR made me end up here, hence the sudden activity Wink

Thanks again for the pointers, and as for "walls of text" - nothing to do with my approach to things, I am just keyboard happy Wink I'll try to constrain myself and be more concise (surely not with this post yet Wink).

 
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« Reply #10 on: October 26, 2016, 03:33:13 PM »

As a noob to torque (not load) based systems, can you explain what torque is in those systems? Because in load based systems (as understand it), torque is an efficiency %, not a fixed number, so 100% torque means different things at many different operating points, unlike load, which is always load.

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ME7.1 tuning guide (READ FIRST)
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ME7Sum checksum checker/corrrector for ME7.x

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience.
mbkr89
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« Reply #11 on: October 27, 2016, 12:14:22 AM »

You have FR from this ECU ?
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woj
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« Reply #12 on: October 27, 2016, 12:18:38 AM »

You have FR from this ECU ?

I don't, if I had I wouldn't be asking questions. Maybe somebody else has?
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woj
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« Reply #13 on: October 27, 2016, 01:34:38 AM »

As a noob to torque (not load) based systems, can you explain what torque is in those systems? Because in load based systems (as understand it), torque is an efficiency %, not a fixed number, so 100% torque means different things at many different operating points, unlike load, which is always load.

Well, the basis seems to be, in the different bins that I have, 100% torque is engine output at some fixed maximum load. In one version 100% torque is the torque that the engine would have at 240% RL, regardless of RPM it seems in one particular case, in another bin this relation varies across the RPM range. BTW, this floating torque figure across the different maps sets for essentially the same engine makes understanding what is really going on even harder.
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nyet
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« Reply #14 on: October 27, 2016, 11:39:47 AM »

Well, the basis seems to be, in the different bins that I have, 100% torque is engine output at some fixed maximum load. In one version 100% torque is the torque that the engine would have at 240% RL, regardless of RPM it seems in one particular case, in another bin this relation varies across the RPM range. BTW, this floating torque figure across the different maps sets for essentially the same engine makes understanding what is really going on even harder.

Well, it makes sense from a driver request standpoint: set a given load max (ie. possible available torque) as a benchmark. For a given fixed torque request, try to meet that request as a % of the benchmark load (available torque).
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ME7.1 tuning guide (READ FIRST)
ECUx Plot
ME7Sum checksum checker/corrrector for ME7.x

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience.
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