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nyet
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« Reply #15 on: June 06, 2014, 01:11:14 PM »
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Pretty sure I did modify them.. I need to spend more time on this as current methods of controlling boost by direct n75 control is leading to issues where actuators settle down over time and where say 65% dc gives 1.4bar one week, a few hot cycles and softening of a new spring leads to 1.1bar and the need for tweaking.. Starting to like the old load based tuning much more for this exact point...
I've also seen the N75 itself start to act differently depending on engine bay temps (i think), which makes things even more unpleasant :/ thinking about relocating it to behind the firewall to see if it makes a difference. |
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NOTORIOUS VR
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« Reply #16 on: June 06, 2014, 01:18:14 PM »
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BTW the two graphs in the first post have drastically different boost ramps.
the runs were started at different times in the RPM band, and slight differences in PID tables since the log was from a much earlier revision where I was still trying to calm everything by editing the PID tables. I'll put these two together where the runs started almost at the exact same point, no throttle opening differences at all. The main difference is that I actually numbed the PID/DRL tables to try to avoid overshoot after not getting anywhere with PID adjustments, so the ramp is longer and boost builds slower in the first graph. But I'm telling you that if the only thing I change between file logged in the bottom graph is putting the axis back to stock, I will have oscillations throughout the RPM band from start to end. throttle press. axis stock:  throttle press. axis stock minus 15% across the board:  |
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phila_dot
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« Reply #17 on: June 06, 2014, 02:01:21 PM »
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The pressure axis is a ratio of desired manifold pressure : ambient pressure.
vpsspls_w is a desired pressure ratio pre-throttle pressure : manifold pressure.
vpsspls_w is used to convert desired manifold pressure pssol_w to desired boost pressure plsol_w.
It is also used to regulate pressure pre and post throttle via the throttle plate. If vpsspls_w is > 0.95, then the throttle plate is forced to open that percentage towards WOT. Anytime vpsspls_w is 1, then the throttle is forced to open 100%.
It has no other function and no direct influence on the boost PID controller.
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phila_dot
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« Reply #18 on: June 06, 2014, 02:15:45 PM »
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Target boost pressure is lower in the second one.
Is it switching back to dynamic mode or remaining in steady state?
We really need to see the PID terms at least.
The PID response looks crazy aggressive to me.
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nyet
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« Reply #19 on: June 06, 2014, 02:19:56 PM »
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Log WG pre-lin.
something is very wrong with your LDRL perhaps?
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userpike
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« Reply #20 on: June 06, 2014, 03:17:03 PM »
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Hey nyet, how off are the logs if the PID parameters aren't set up correctly in xPlot?
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nyet
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« Reply #21 on: June 06, 2014, 03:19:48 PM »
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The PID parameters are only for the CALC functions (if you want to simulate a PID given a set of data to see how it would respond)
As an aside, this "simulation" isn't really complete because it is stateless; it only shows what the pid value would be given a set of inputs... it can't manipulate the DC and predict how the system would respond.
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NOTORIOUS VR
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« Reply #22 on: June 08, 2014, 05:48:05 AM »
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The pressure axis is a ratio of desired manifold pressure : ambient pressure.
vpsspls_w is a desired pressure ratio pre-throttle pressure : manifold pressure.
vpsspls_w is used to convert desired manifold pressure pssol_w to desired boost pressure plsol_w.
It is also used to regulate pressure pre and post throttle via the throttle plate. If vpsspls_w is > 0.95, then the throttle plate is forced to open that percentage towards WOT. Anytime vpsspls_w is 1, then the throttle is forced to open 100%.
It has no other function and no direct influence on the boost PID controller.
I"ll get some more data soon... in any case modding just the axis made the car found like it's boosting but something else is going on (looks like the car trying to correct the boost by taking away timing). anyway, I've reverted back to a much tamer file, I'll throw up some logs soon for it. Still according to Phila logging the vpsspls_w variable is enough to setup the maps/axis properly in these two maps, correct? |
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ddillenger
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« Reply #23 on: June 08, 2014, 05:57:27 AM »
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It's a pressure ratio. No logging required, just set it based on your wastegate pressure.
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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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phila_dot
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« Reply #24 on: June 08, 2014, 11:59:20 AM »
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The axis variable is vpssplg_w and can be logged itself.
Keep in mind that the pressure ratio, vpssplg_w, is based on desired intake manifold pressure pssol_w, so it's post throttle and will always be less than or equal to desired pressure at the MAP sensor plsol_w which is pre-throttle.
Assuming:
a) the MAF and scaling is reporting true airflow
b) you're running a proper 5120 or not maxing out the pressure variables
c) no other parts of the model are messed up
ps_w should follow pssol_w and rl_w should follow rlsol_w.
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phila_dot
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« Reply #25 on: June 08, 2014, 12:29:03 PM »
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To explain it as simply as possible,
The map is used to request a 1:1 ratio pre and post throttle, i.e. full throttle.
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masterj
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« Reply #27 on: March 17, 2015, 02:24:43 PM »
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Sorry to bring up old topic but I have some weirdness with dwdksut_w and was thinking of updating KFVPDKSD/KFVPDKSE to all 1s. Will that help me to overcome that dwdksut_w "swing" (please look attached log screenshot)? Currently dwdksut_w makes my throttle plate go 100% -> ~80% -> 100% in 1000-1520 rpm zone.
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masterj
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« Reply #28 on: March 19, 2015, 02:01:13 PM »
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Anyone who has tuned K04-015 or K03s what have you set in these maps (KFVPDKSD/E)? Screenshots would be most welcome  I kinda am thinking of setting everything to 1s (as it is done in 2.7T A6) or just copy RS4 values here as a starting point... |
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« Last Edit: March 19, 2015, 02:08:00 PM by masterj »
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