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carsey
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« on: May 16, 2014, 10:23:05 AM »
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Hi Another newbie question again  Just wondering how KFLDRL 'linearises' the boost. I know I can cap N75 DC% with KFLDIMX however since using the 032hn KFLDRL on my k04 ECU running k03s turbo the boost was 5psi less. IMX values are still up in the 95% through spool dropping to ~85% midrange so should have plenty of duty to keep things boosting. A couple pics of the maps in question are attached Top - KFLDIMX Middle - KFLDRAPP Bottom - KFLDRL Im not too sure how/what KFLDRAPP does but the 032HN one was different to K04 so I changed that over too. Does KFLDRL use the bottom line for full throttle since thats 95% throttle plate angle? When i did a quick log the duty cycles were ~65% and actual engine load not meeting specified. Anyone any pointers? |
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nyet
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« Reply #1 on: May 16, 2014, 11:00:24 AM »
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1) it does not linearize boost, it linearizes the wastegate response to the output of the PID
2) KFLDRL has NOTHING TO DO WITH THROTTLE PLATE ANGLE
3) KFLDRAPP does nothing unless you enable it via CWDMAPP
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« Last Edit: May 16, 2014, 11:02:00 AM by nyet »
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phila_dot
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« Reply #2 on: May 16, 2014, 11:16:08 AM »
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4) KFLDIMX does not cap N75 DC. It is the base for the upper and lower I limits.
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carsey
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« Reply #3 on: May 16, 2014, 01:52:29 PM »
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Bit more reading for me it appears Shame everything is in german on the FR
Doesnt help in a poor learner just by reading things either. I have to put into practice the parts and then top it up with the theory after.
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nyet
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« Reply #4 on: May 16, 2014, 03:20:36 PM »
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The result of the PID is the input to KFLDRL. The output of KFLDRL goes to the N75. That part of the FR is not in german, it is in the block diagram.
You'll also want to brush up on how PIDs work and why the output of PID often has to be linearized before feeding it into the control system...
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userpike
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« Reply #5 on: May 16, 2014, 03:28:00 PM »
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Bit more reading for me it appears Shame everything is in german on the FR
Google translate is your friend. It has really come a long way. I feel it translates better than even a few months ago. So far the best explanation of PID tuning I have found to date: http://youtu.be/SefKQb9y_B4 |
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« Last Edit: May 16, 2014, 03:34:40 PM by userpike »
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ddillenger
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« Reply #6 on: May 16, 2014, 03:43:14 PM »
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I reallllllly would like someone to help me rewrite the PID section of the s4wiki.
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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!
Email/Google chat:
DDillenger84(at)gmail(dot)com
Email>PM
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userpike
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« Reply #7 on: May 17, 2014, 01:52:42 AM »
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I reallllllly would like someone to help me rewrite the PID section of the s4wiki.
working on it. |
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carsey
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« Reply #8 on: May 17, 2014, 04:35:41 AM »
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That video is pretty helpful in understanding how the PID works to get the output wanted.
Looking at the LDRPID section I think I can see the P,I,D sections of it.
P - ldptv
I - lditv_w
D - ldptv
These will stabilize the boost to the output map of KFLDRL, which will then give the duty cycle to the wastegate?
Does this then mean that the base N75 input maps to the PID controller are: (P) - KFLDRQ0, (I) - KFLDRQ1, (D) - KFLDRQ2
Sorry if im talking a load of rubbish, but ill try get my head round it all at some point
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Rick
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« Reply #9 on: May 17, 2014, 05:00:52 AM »
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yes
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userpike
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« Reply #10 on: May 17, 2014, 08:06:15 AM »
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That video is pretty helpful in understanding how the PID works to get the output wanted.
Looking at the LDRPID section I think I can see the P,I,D sections of it.
P - ldptv
I - lditv_w
D - ldptv
These will stabilize the boost to the output map of KFLDRL, which will then give the duty cycle to the wastegate?
Does this then mean that the base N75 input maps to the PID controller are: (P) - KFLDRQ0, (I) - KFLDRQ1, (D) - KFLDRQ2
Sorry if im talking a load of rubbish, but ill try get my head round it all at some point
you are getting there. now read the attachment. I am going to refine it a bit more and then write my interpretation of the sentences that still aren't making total sense. I finished at like 5 am and went to bed so I still need to reread it still. I have to go to work soon though so after. The text is a complete and direct translation of the LDRPID section from the FR through Google translate. I manually corrected what Google translate didn't as far as accent marks above letters and moving words up lines in the translate input box so that the translator didn't get so confused on where the end of the sentences are. Some of the German words have capitals in the middle of sentences which screws shit up in google translate, also periods(.) in odd spots help not either..other translations I've found seem to have simply C&P from the FR into a translator and left rough, and it makes a big difference in the translation. |
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phila_dot
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« Reply #11 on: May 17, 2014, 08:46:49 AM »
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During spool :
Q0DY - P shoots up and is your main influence
Q1DY - is building I up for later
Actual approaching target:
Q2 - aggresively offsets DC to correct under/overshoot
Steady state:
IMX - contains I (there are maps that offset IMX conditionally as well and adaptation)
Q0ST - small corrections
Q1ST - small corrections
P only corrects present error so it drives spool and does small corrections in steady state. I is built by the accumulation of past error, so it is the main value during steady state. D is predictive of future error by using the lde delta and is only active in dynamic state (-lde).
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« Last Edit: May 17, 2014, 09:19:31 AM by phila_dot »
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nyet
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« Reply #12 on: May 17, 2014, 09:34:55 AM »
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I will attempt to edit the translation time permitting as well. Thanks userpike!
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carsey
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« Reply #13 on: May 18, 2014, 05:05:28 AM »
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Think ive had a bit read now.
So KFLDRL is the duty cycle map for the WG DC%. The 'I' part of the PID will be the upper limit for the DC% which is map KFLDIMX. Raising that will allow greater headroom for the WGDC% to meet those set in KFLDRL.
What does the % axis mean in KFLDRL. From the FR it looks to be the output of the PID controller (LDTVR_W).
LDTVR_W - calculated output of the P,I,D functions?
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nyet
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« Reply #14 on: May 18, 2014, 11:16:07 AM »
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Both the input and the output of KFLDRL are duty. The input is the DC from the PID, the output is the linearized DC. unity gain would be 0: 0 0 0 0....
10: 10 10 10 10....
20: 20 20 20 20....
30: 30 30 30 30....
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80: 80 80 80 80....
95: 95 95 95 95....
such that input == output everywhere. Look in your ME7L config (you should already have logged these before touching your PID) ldtv , {WastegateDutyCycleAfterLin} , 0x382752, 2, 0x0000, {%} , 1, 0, 0.005, 0, {LDR Tastverh▒ltnis}
ldtvr_w , {WastegateDutyCycleBeforeLin} , 0x382754, 2, 0x0000, {%} , 1, 0, 0.005, 0, {LDR Tastverh▒ltnis vom Regler}
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