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Author Topic: MED9 LDRLMX  (Read 7460 times)
dgpb
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« on: February 19, 2021, 05:39:51 PM »

Hello after a long time.

I'm now a 1p cupra happy owner. I read its flash with MPPS some days ago and was preparing my definition (1P0907115C) from a well defined 1K0907115S from this forum. I'm totally open to share it once it's more or less ok.

Good. I come from me7 and I know pretty well the algorythm from the title. However, in MED9 it's more different than I would've expected... I guess it follows the same principle though:



At first sight, as LDORXN is lower than LDRXN (from rlmx_w), both go to the minimum selector and LDORXN (Absurdly low in my opinion, something like load 30) becomes plxs_w (by pressure transformation).

Obviously, this is not what happens without E_lde (overboost error).

So I assume the explanation is in the [IF] block working mode. For sure it has something to do with the arrow numeration, but I don't understand it's behaviour. I even tried to look at the begining of FR but nah... not clear enough.

Could someone explain to me how/why this works and wtf is LDORXN so stupid low?

Thanks a lot for your time mates

Ps: My presumption is that the latest option from the active [IF] becomes directly the last variable affected by any present [IF], no matter what's up/downwards. But even so, I couldn't find E_tnl so I don't know what it means. What's more, what should happen in the event of no E_xxx, aka, no errors? The [ELSE] from the only [IF] that has one? (then, ignoring LDPNB)
« Last Edit: February 19, 2021, 06:06:09 PM by dgpb » Logged
dgpb
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« Reply #1 on: February 20, 2021, 10:21:35 AM »

Any help guys?
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nyet
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« Reply #2 on: February 21, 2021, 09:39:02 PM »

Not quite sure but this is my guess:

lets ignore E_tnl for the moment:

call the minimum of rlmx_w (corrected), ldrlts_w, ldrlms_w, and LDORXN some variable "foo"

Now, the purpose of that flip flop is to inhibit updating plxs_w from foo while B_ll

As long as B_ll is false or E_lde is true, plxs_w is updated by "foo" on the 50ms raster

As soon as B_ll goes true and E_lde goes false, the flip flop resets to false, NOT IF is triggered and plxs_w stops being updated by "foo", until E_lde becomes true again, and plxs_w starts getting updated by "foo" again.

Do the same for E_tnl, roughly, to add it back in with respect to the raster update.

I could be wrong, of course.
« Last Edit: February 21, 2021, 09:42:38 PM by nyet » Logged

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« Reply #3 on: February 22, 2021, 06:14:35 AM »

This is the clusterfuck in the FR that is the hardest to understand.

But how you should read it, is that this minimum is evaluated only in case B_emxldr or E_lde are set.
Otherwise this minimum is not evaluated.

LDORXN is so stupid low because it's basically for limp mode.
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dgpb
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« Reply #4 on: February 22, 2021, 06:12:18 PM »

I think we understand more or less the same from the diagram...

This would've been a lot clearer if bosch used triggerable selectors (in my humble opinion) as they usually do in many other algorythms

And regarding LDORXN, from what I remember from me7, it is much higher there... Isn't it? But well, that's secondary

Thank you both guys
« Last Edit: February 22, 2021, 06:19:37 PM by dgpb » Logged
nyet
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« Reply #5 on: February 22, 2021, 10:26:04 PM »

I think we understand more or less the same from the diagram...

This would've been a lot clearer if bosch used triggerable selectors (in my humble opinion) as they usually do in many other algorythms

And regarding LDORXN, from what I remember from me7, it is much higher there... Isn't it? But well, that's secondary

No. The description is also pretty clear: "Maximalfuellung LDR bei E_ldo (Überladefehler)"
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dgpb
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« Reply #6 on: February 23, 2021, 04:23:31 AM »

No. The description is also pretty clear: "Maximalfuellung LDR bei E_ldo (Überladefehler)"

The description is in fact the same, but values are much lower:

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« Reply #7 on: February 23, 2021, 05:00:35 PM »

I thought you meant higher than LDRXN
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« Reply #8 on: February 23, 2021, 05:13:13 PM »

So they just limited it harder.
What's so special? Nothing Smiley
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dgpb
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« Reply #9 on: April 16, 2021, 03:18:54 PM »

Hello again,

I made a very soft "stage0.5" to validate the concept, +20g/s.

Installed an aftermarket intake (I know, not needed for that, but my plans are to go harder) and adjusted maf a tiny bit to reduce fuel trims as much as possible.

It goes quite well in my opinion now. HOWEVER, I've got to regulate my right foot even in 3rd if I don't want to do burnouts out of several corners (don't wanna imagine with higher requests)... So as my short term plans aren't compatible with an lsd I thought to limit torque by gear up to 3rd

I read that some mates here have experienced timing issues by using KFMDBGRG... So I thought is the perfect oportunity to start with IDA. Will it be very optimistic to start by assigning different lrdxn(s) or even ldorxn/kfldhbn... To different gears?

I've never modified anything with ida to my ex-golf aum, but I've got some degree of assembly knowledge with some good old PICs

Do you recomend me to go ahead? Or it's not a reallistic approach?

What I have in mind is something like search the variable rlmx_w and inject some "bit skip if" whatever bit is set, and assign the output of the LDRXXXX I want

And then, tune that maps for each gear.
« Last Edit: April 16, 2021, 03:28:35 PM by dgpb » Logged
prj
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« Reply #10 on: April 17, 2021, 02:32:55 AM »

The ECU can already limit torque by gear with stock maps.
There are different maps. One of them is for "load path", which does not cause any timing intervention and is also used by OEM's.

That said, I don't see what is bad about timing intervention when you are limiting the torque. If you want precise torque then you are going to need some timing intervention to keep it there.
It's only active at WOT, and only in the gears you are limiting, not like you get bad timing all the time.

But as I said, you can just limit the load path as well. No need for IDA or any other shenanigans.
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dgpb
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« Reply #11 on: April 17, 2021, 04:04:15 AM »

The ECU can already limit torque by gear with stock maps.
There are different maps. One of them is for "load path", which does not cause any timing intervention and is also used by OEM's.

That said, I don't see what is bad about timing intervention when you are limiting the torque. If you want precise torque then you are going to need some timing intervention to keep it there.
It's only active at WOT, and only in the gears you are limiting, not like you get bad timing all the time.

But as I said, you can just limit the load path as well. No need for IDA or any other shenanigans.

Thanks prj, I'll take a look.

Btw, the reason why I don't wanna reduce torque by timing is cause I don't want my egts to go high... If you want to reduce 5-10 Nm, maybe it's ok. But for 50? I consider it excesive.
« Last Edit: April 17, 2021, 04:06:03 AM by dgpb » Logged
prj
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« Reply #12 on: April 17, 2021, 05:52:49 AM »

Why do you think it will reduce it by timing alone? It won't.
It just uses fast path intervention to do the last part for which the slow path intervention does not kick in soon enough.

If you base everything you know just on reading a forum, then most likely you will have a very skewed view of things which is far out of touch with reality.

Just try setting it and log the car...
As I said there's another map that does it on slow path only IIRC gangi x tmot. Don't remember the name without looking it up.
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dgpb
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« Reply #13 on: April 17, 2021, 06:07:47 AM »

Why do you think it will reduce it by timing alone? It won't.
It just uses fast path intervention to do the last part for which the slow path intervention does not kick in soon enough.

If you base everything you know just on reading a forum, then most likely you will have a very skewed view of things which is far out of touch with reality.

Just try setting it and log the car...
As I said there's another map that does it on slow path only IIRC gangi x tmot. Don't remember the name without looking it up.

"If you base everything you know just on reading a forum, then most likely you will have a very skewed view of things which is far out of touch with reality."

Hahahahaha

I don't. But I prefer to go more or less guided towards the algorythm I need in FR rather than searching for it blindly.

Anyway, it's pointless to keep talking before trying it out. Thanks guys and I'll keep you informed.

Ps: Yep, gangi is obviously one input for KFMDBGRG. I'll search for that and post map's name in case I find it. Although tmot reminds me MDBRGA or something like that... It exists in me7 but not med9. Maybe it' just got other name.
« Last Edit: April 17, 2021, 07:07:04 AM by dgpb » Logged
dgpb
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« Reply #14 on: April 17, 2021, 07:33:13 AM »

I think this is what you explained before prj:

Die Funktion %MDBGRFZG berechnet eine reduzierende Momentenanforderung des Fahrzeugs, die in der Funktion %MDBGRMOT mit reduzierenden Momentenanforderungen des Motors zu einer begrenzenden Gesamtanforderung koordiniert wird.
Die reduzierende Gesamtanforderung aus der Funktion %MDBGRMOT wird in der Koordination der Momente (%MDKOL, %MDKOG) berÜcksichtigt. Die AusgangsgrÖße mibgrfzl_w wirkt auf den ’langsamen’ Luftpfad, wÄhrend mibgrfz_w den ’schnellen’ kurbelwinkelsynchronen Pfad begrenzt.

The% MDBGRFZG function calculates a reducing torque request from the vehicle, which is coordinated in the% MDBGRMOT function with reducing torque requests from the engine to form a limiting overall request.
The reducing overall requirement from the% MDBGRMOT function is taken into account in the coordination of the moments (% MDKOL,% MDKOG). The output variable mibgrfzl_w acts on the ’slow’ air path, while mibgrfz_w limits the ’fast’ crank angle-synchronous path.

« Last Edit: April 17, 2021, 08:35:23 AM by dgpb » Logged
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