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Author Topic: Actual pre-control in LDRPID  (Read 43195 times)
cgramme
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« Reply #210 on: July 12, 2018, 01:43:52 PM »

I think I found the problem. When comparing KFLDRL with an unmodified version of KFLDRL I get this. This would explain the dips that wgdc was following. Wow. I have no idea how I got this improper definition, but finding this makes me very happy.

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cgramme
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« Reply #211 on: July 12, 2018, 02:40:17 PM »

So I have redefined KFLDRL. This is what it was following... notice that the map isn't on the correct axis.

« Last Edit: July 25, 2018, 12:10:25 AM by cgramme » Logged
cgramme
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« Reply #212 on: July 12, 2018, 04:07:36 PM »

Not perfect by any means, but wgdc is now making sense.   Grin Finally I can get to dialing it in.

Thank you guys for all the help, and for an excellent tuning method!

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SB_GLI
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« Reply #213 on: July 12, 2018, 06:40:33 PM »

Not perfect by any means, but wgdc is now making sense.   Grin Finally I can get to dialing it in.

Thank you guys for all the help, and for an excellent tuning method!


This is where I will just modify the KFLDIMX axis by a fixed percent, and it's usually perfect after that. KFLDRL is set how you want it, now you just have to line KFLDIMX up with it.  Since you are underboosting, subtract 10-15 percent across the whole pressure axis.  Try it!
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cgramme
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« Reply #214 on: July 13, 2018, 05:48:46 PM »

Subtracted 5% from KFLDIMX mbar axis, raised LDRXN slightly, and completely linearized KFLDRL as an experiment. I need to get some higher +60% wgdc logs so I can repopulate KFLDRL the proper way with the tool. Also, other than a custom downpipe my exhaust is basically stock, so that'll be addressed very soon. Would you think the dips in boost pressure could be symptoms of a restrictive exhaust/wastegate?

Next I will be raising KFLDIMX mbar axis by 5-10% and see what happens.

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dream
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« Reply #215 on: July 16, 2018, 12:20:10 AM »

I've had some time this weekend to try this method.

Altough something isnt right, I think my def is not on spot because ldtvr is not likely to follow ldtvm in any way.

It shows that ldtv is at 95% when it comes from KFLDRL then after TVLDMN and TVLDMX it goes out as ldtvmd (as I can assume it from the FR) then into LDR_APP which comes out as ldtvm. But ldtvm is not even near where I've hoped to get it.

I haven't defined KFLDRAPP in my file (yet). I see that in my H-box its not used because all the values are 0. I am not sure but I am guessing they dint used it also either in a 6K0906032AA Seat file.
From my understanding from the FR is that KFLDRAPP is used when B_ldsapp = 1, so I am not sure if this would be the issue why my DC (ldtvm) is not in range with my KFLDRL (ldtv).

I have CWMDAPP 8 and because of the low actual boost it threw an DTC negative deviation which I think it caused the ldtvr_w and ldtv drop to zero in the log.

Anyway I don't understand why my WGDC is acting this way.

Also I am not yet confidend using the LDRPIDTool, but I am still going to work that out.
« Last Edit: July 16, 2018, 03:46:52 AM by dream » Logged
dream
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« Reply #216 on: July 16, 2018, 04:04:29 AM »

I think I found the issue regarding to FR cuz CWMDAPP = 8 (Feinabstimmung LDRXN, sowie Applikation aller Korrektureingriffe für rlmax (%LDRLMX)), which activates KFLDRAPP (which I haven't defined yet in my file).
So I am supposed to understand where the difference of ldtv and ldtvm is coming from.

Now I am going to find KFLDRAPP and see if the log is compared with the map.
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SB_GLI
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« Reply #217 on: July 18, 2018, 01:12:58 PM »

I think I found the issue regarding to FR cuz CWMDAPP = 8 (Feinabstimmung LDRXN, sowie Applikation aller Korrektureingriffe für rlmax (%LDRLMX)), which activates KFLDRAPP (which I haven't defined yet in my file).
So I am supposed to understand where the difference of ldtv and ldtvm is coming from.

Now I am going to find KFLDRAPP and see if the log is compared with the map.

Seems you might have put the cart before the horse.  You need to set KFLDRAPP to have a fixed WGDC in order to log fixed WGDC runs.
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aef
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« Reply #218 on: July 18, 2018, 04:18:27 PM »

I have to change the ambient and all of the axis in your tool, right?

Or is the ambient just a filter for lets say: please use only the parts of the log with this exact ambient?

Can i add additional logs to the folder for more details with 65, 75, 85% duty or will it just use the ones matching the axis of KFLDRL in the tool?
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dream
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« Reply #219 on: July 20, 2018, 12:21:48 AM »

Seems you might have put the cart before the horse.  You need to set KFLDRAPP to have a fixed WGDC in order to log fixed WGDC runs.

I think I found KFLDRAPP (see picture).
I am going to alter it and test it later today in the car and see what the results are.

About the duty cycle in my last log,could it be that ldtvm was coming from vsldtv?
Because the KFLDRAPP was all 0'ed and FR shows it adds vsldtv before it goes out as ldtvm.
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SB_GLI
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« Reply #220 on: July 20, 2018, 06:24:31 AM »

I have to change the ambient and all of the axis in your tool, right?

Or is the ambient just a filter for lets say: please use only the parts of the log with this exact ambient?

Can i add additional logs to the folder for more details with 65, 75, 85% duty or will it just use the ones matching the axis of KFLDRL in the tool?

The fixed DC log's WGDC does not have to match the axis.  Ambient is just an override in the case that it's not included in your log.
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jpurban
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« Reply #221 on: July 20, 2018, 09:57:34 AM »

Question regarding the design points of KFLDIMX desired pressure (pssol) axis, specifically setting the low axis point.  I've completed all the necessary runs at fixed DC -- just need some education to make sure I implement this correctly.  My boost control is seems acceptable now, but I want to try this approach if it offers any improvement...  Why not, right?

Here's what I think I've gleaned so far from this thread -- Please feel free to correct me:
1) KFLDIMX pssol axis should be distributed evenly, making linearization of the table values as easy as possible
2) KFLDIMX pssol high axis point should be above maximum achievable boost (not max desired boost).  This is done to ensure full range is covered (last row of KFLDRL table values is all 95).  LDRXN/KFLDHBN may limit boost below this level, but can be ignored here.
3) KFLDIMX pssol low axis point should be below "base boost"...

This may be a really dumb question...  What is the definition of "base boost"?  Intuitively, I think it is the curve representing maximum achievable boost at WGDC = 0 as a function of engine speed.  The value is lower at low rpm and peaks at a higher rpm, but before redline (for most turbos).  Is this correct? 

If so, what value of "base boost" do you use as the pssol low axis point since it varies?  My OEM file uses 1150, which is close to the maximum WGDC=0 boost achievable with the OEM 6 psi wastegate at any engine speed.  My wastegate pressure has been increased from about 6 psi OEM to 12 psi and my car will achieve about 1.6 bar (1600) at higher engine speeds at WOT and WGDC=0.

« Last Edit: July 20, 2018, 10:44:37 AM by jpurban » Logged
SB_GLI
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« Reply #222 on: July 20, 2018, 11:18:45 AM »

Question regarding the design points of KFLDIMX desired pressure (pssol) axis, specifically setting the low axis point.  I've completed all the necessary runs at fixed DC -- just need some education to make sure I implement this correctly.  My boost control is seems acceptable now, but I want to try this approach if it offers any improvement...  Why not, right?

Here's what I think I've gleaned so far from this thread -- Please feel free to correct me:
1) KFLDIMX pssol axis should be distributed evenly, making linearization of the table values as easy as possible
2) KFLDIMX pssol high axis point should be above maximum achievable boost (not max desired boost).  This is done to ensure full range is covered (last row of KFLDRL table values is all 95).  LDRXN/KFLDHBN may limit boost below this level, but can be ignored here.
3) KFLDIMX pssol low axis point should be below "base boost"...

This may be a really dumb question...  What is the definition of "base boost"?  Intuitively, I think it is the curve representing maximum achievable boost at WGDC = 0 as a function of engine speed.  The value is lower at low rpm and peaks at a higher rpm, but before redline (for most turbos).  Is this correct? 

If so, what value of "base boost" do you use as the pssol low axis point since it varies?  My OEM file uses 1150, which is close to the maximum WGDC=0 boost achievable with the OEM 6 psi wastegate at any engine speed.  My wastegate pressure has been increased from about 6 psi OEM to 12 psi and my car will achieve about 1.6 bar (1600) at higher engine speeds at WOT and WGDC=0.


Everything you said here is accurate.   Don't overthink the low axis point.   Just pick a value that is below the amount of boost the turbo can produce at 0% WGDC where it's no longer ramping up.
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jpurban
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« Reply #223 on: July 20, 2018, 09:07:46 PM »

Thanks for the quick confirmation.  I'll give it a go tomorrow.

*** Update:  Sharing my experience, for whatever it is worth... This method produced boost control at least as good as my best prior attempts, probably better.  No overshoot issues.  Didn't require any changes to boost PID. I'm sticking with it because it removes one variable (KFLDIMX) and makes fine tuning boost control in KFLDRL more straightforward.  Thanks to PRJ and SB_GLI for this thread.***
« Last Edit: July 24, 2018, 09:57:55 PM by jpurban » Logged
cgramme
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« Reply #224 on: July 30, 2018, 06:01:58 PM »

I've been trying to smooth the oscillations out of my boost profile, but I think I'm dealing with something I haven't seen in any other posts here or on other sites. I believe a "normal" linear wgdc pull should make a boost profile without a boost spike like I am getting from my turbo. Has anyone seen this type of spike from a linear wgdc pull? I can only assume it has to do with the wastegate itself, which might be too small or just not opening correctly initially. I am using a cheap t3/t4 .63 / .50 trim turbo with internal wastegate. The wastegate has been bench tested and seems to function properly and the turbo runs nicely except for this spike. Maybe my wastegate preload is set too high? Any ideas?



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