|
littco
|
 |
« Reply #30 on: June 01, 2016, 02:02:46 AM »
|
|
|
ok i can do that.
Can you perhaps explain how the ECU selects an WGDC? I've read the Wiki but cant really figure it out.
I assumed it used IMX, but looking at that table it appears to reference WGDC against ambient pressure? I expected there would be a table of WGDC against boost and rpm? The wiki seems to suggest that IMX should follow the WGDC at WOT? yet in the stock file, its up in the 70-80% range across the board? Does the little 5psi actuator need that much DC to produce 12psi?
Is there some way i can cap maximum WGDC to stop it spiking stupidly while i'm trying to figure out why its running so much WGDC? Theres no way i'm going full throttle again with it in its current state. I like my engine in one piece. If i'm right above, i presume i can limit the top two rows of IMX to say 30%?
Cheers
Kev
To cap the boost you need to set KFLDRL to the max you want by RPM AND THROTTLE or you cap set an absolute limit with TVLDMX which is the max n75 DC. It wont go above that. |
|
|
|
|
Logged
|
|
|
|
Aragorn
Full Member
Karma: +3/-0
 Offline
Posts: 94
|
|
« Reply #31 on: June 01, 2016, 02:27:22 AM »
|
|
|
Does DRL have a throttle input? I thaught input was WGDC from the pid? So if i cap it with TVLDMX, will the logging a WOT pull still show what the PID controller is trying to do? I've found the big thread on here which discusses using KFLDRAPP to set fixed duty cycles and logging. I think thats probably where i need to start? http://nefariousmotorsports.com/forum/index.php?topic=517.msg4028#msg4028 |
|
|
|
|
Logged
|
|
|
|
|
armageddon
|
|
« Reply #32 on: June 01, 2016, 05:18:43 AM »
|
|
|
ok that IMX axis isnt atmospheric is it? Its boost...
Means it only goes up to 1 bar as stock though?
my understanding is that imx axis is mbar above atmospheric pressure, could be wrong... |
|
|
|
|
Logged
|
|
|
|
|
nyet
|
|
« Reply #33 on: June 01, 2016, 11:29:28 AM »
|
|
|
Can you perhaps explain how the ECU selects an WGDC? I've read the Wiki but cant really figure it out.
You'll have to read up on PIDs and read the FR. The input to the PID is lde (requested pressure - actual pressure) and there is a ton of gain scheduling also done. The output is WGDC pre-lin, which goes into DRL. If I were to add an explanation of PIDs to the wiki, it would be 100 pages long. I assumed it used IMX, but looking at that table it appears to reference WGDC against ambient pressure? I expected there would be a table of WGDC against boost and rpm?
No. The wiki seems to suggest that IMX should follow the WGDC at WOT? In the absence of all other inputs, a PID will follow the accrued I value, which, in ME7, is limited by IMX yet in the stock file, its up in the 70-80% range across the board? Does the little 5psi actuator need that much DC to produce 12psi?
In some conditions, yes. Is there some way i can cap maximum WGDC to stop it spiking stupidly while i'm trying to figure out why its running so much WGDC? Theres no way i'm going full throttle again with it in its current state. I like my engine in one piece. If i'm right above, i presume i can limit the top two rows of IMX to say 30%?
Yes, you can do that but I think you are wasting your time. You need to start with a stock file. Cap DRL is the safest, it is the last step before WGDC. I've found the big thread on here which discusses using KFLDRAPP to set fixed duty cycles and logging. I think thats probably where i need to start?
I think you need to start by figuring out how PIDs work before doing ANY tuning. |
|
|
|
|
Logged
|
|
|
|
|
littco
|
|
« Reply #34 on: June 01, 2016, 01:17:04 PM »
|
|
|
You'll have to read up on PIDs and read the FR. The input to the PID is lde (requested pressure - actual pressure) and there is a ton of gain scheduling also done. The output is WGDC pre-lin, which goes into DRL. If I were to add an explanation of PIDs to the wiki, it would be 100 pages long.
No.
In the absence of all other inputs, a PID will follow the accrued I value, which, in ME7, is limited by IMX
In some conditions, yes.
Yes, you can do that but I think you are wasting your time. You need to start with a stock file.
Cap DRL is the safest, it is the last step before WGDC.
I think you need to start by figuring out how PIDs work before doing ANY tuning.
Nyet , Have you tried taming the PIDS on the 1.8t files, unlike the 2.7 files its not that easy and from experience the easiest way to control the actuator when its over stock is open loop via KFLDRL. It works perfectly well and far easier than trying to set up the PID maps to control the n75. My suggestion and it is only that, is to raise LDRXN out the way, then disable the maf diagnosis maps and increase the boost deviation, set IRL and IOP enough to cope with your new loads and simply map the boost using KFLDRL ie n75 DC.. |
|
|
|
|
Logged
|
|
|
|
|
nyet
|
|
« Reply #35 on: June 01, 2016, 01:21:03 PM »
|
|
|
Have you tried taming the PIDS on the 1.8t files, unlike the 2.7 files its not that easy and from experience the easiest way to control the actuator when its over stock is open loop via KFLDRL.
Honestly, never had a problem tuning the 1.8t pid. 99% of the work is in IMX and DRL. You don't even really need to tweak Q2 if IMX and DRL are set up right. You can even use "almost" open loop by clamping DRL around the area you want PID control to be limited to.. |
|
|
|
|
Logged
|
|
|
|
|
littco
|
|
« Reply #36 on: June 01, 2016, 01:36:44 PM »
|
|
|
Honestly, never had a problem tuning the 1.8t pid.
99% of the work is in IMX and DRL. You don't even really need to tweak Q2 if IMX and DRL are set up right. You can even use "almost" open loop by clamping DRL around the area you want PID control to be limited to..
I agree with this but I think by adjusting the DRL you are really open loop still as the pids aren't really learning or adjusting as they would in a true closed loop system, you aren't setting the ECU up to run the stronger actuator just stopping it from uncontrollably going above, the Pid isn't really controlling in the strict sense, I can see it working though.. My personal choice is just go open loop and set the n75 dc where you want it... and with a little effort you can get a pretty good boost profile.. |
|
|
|
|
Logged
|
|
|
|
|
nyet
|
|
« Reply #37 on: June 01, 2016, 01:45:04 PM »
|
|
|
I agree with this but I think by adjusting the DRL you are really open loop still as the pids aren't really learning or adjusting as they would in a true closed loop system, you aren't setting the ECU up to run the stronger actuator just stopping it from uncontrollably going above, the Pid isn't really controlling in the strict sense, I can see it working though.. My personal choice is just go open loop and set the n75 dc where you want it... and with a little effort you can get a pretty good boost profile..
Except if the temp changes, or the altitude changes, or ... etc. etc. the boost will drift, and unless you numb all the deviation codes, you'll eventually throw a code. Even worse, fueling might start going all over the place too, unless you're really anal about getting fueling right at a variety of WOT boost levels. The latter isn't as big a deal on wideband 1.8ts, though so we can agree to disagree. To each his own. I have no problem with people who decide on open loop boost control, as long as they're aware of the downsides. |
|
|
|
|
Logged
|
|
|
|
|
Rick
|
|
« Reply #38 on: June 01, 2016, 02:44:12 PM »
|
|
|
It's a base file purely to allow running on the larger injectors. Boost control is standard and it will almost certainly go straight into limp with the stiffer actuator. It will run full closed loop when it's finished  Rick |
|
|
|
|
Logged
|
|
|
|
Aragorn
Full Member
Karma: +3/-0
Offline
Posts: 94
|
|
« Reply #39 on: June 01, 2016, 02:52:29 PM »
|
|
|
Cheers Rick I did say quite a few times that the file was stock, some reason they're jumping to conclusions that its been buggered about with. Thanks for all the help guys, just a little too much too soon i think. It needs time spending learning whats going on and i just dont have the time at the moment. Managed to get it booked in next week, so the wife will stop bending my ear about "messing with her car"  I think i'd be better starting with a "stage1" type tune and working my way up, hopefully i'll get my track car converted to ME7.5 in a few months and sort out a tune on its standard turbo, and work my way up from there. Cheers Kev |
|
|
|
|
Logged
|
|
|
|
|
nyet
|
|
« Reply #40 on: June 01, 2016, 02:53:35 PM »
|
|
|
Cheers Rick I did say quite a few times that the file was stock, some reason they're jumping to conclusions that its been buggered about with. You claim you want to learn (and diagnose the problem), but you've ignored me every time i've said this, including my requests to log the PID variables Rick, if this is your base file, what am I missing? |
|
|
|
« Last Edit: June 01, 2016, 02:55:49 PM by nyet »
|
Logged
|
|
|
|
Aragorn
Full Member
Karma: +3/-0
Offline
Posts: 94
|
|
« Reply #41 on: June 01, 2016, 03:08:37 PM »
|
|
|
I didnt get a chance to log the PID vars, Work and babies get in the way of tinkering with cars!
Spent this evening replacing some pipes that had been chafing and sorting out the cruise control stuff, which incidentally works perfectly, leaving me quite chuffed that i managed to disassemble the file, find the ram variable and log the required info. Clearly some learning is happening. Just not with PID controllers.
You've said a few times that lde<0 shouldnt result in a DC >10, yet the logs clearly show exactly that happening. I'm not an expert, i'm a noob learning how to tune ME7.5. If you dont know why its requesting significant WGDC when lde<0 then how do you expect me to know!?
|
|
|
|
|
Logged
|
|
|
|
|
nyet
|
|
« Reply #42 on: June 01, 2016, 03:13:50 PM »
|
|
|
If you dont know why its requesting significant WGDC when lde<0 then how do you expect me to know!?
Specifically, addressing your statement: they're jumping to conclusions that its been buggered about with
And, generally, one good reason not to use open loop boost control.. |
|
|
|
« Last Edit: June 01, 2016, 03:15:36 PM by nyet »
|
Logged
|
|
|
|
Aragorn
Full Member
Karma: +3/-0
Offline
Posts: 94
|
|
« Reply #43 on: June 01, 2016, 03:29:21 PM »
|
|
|
I dont really understand your response.
Are you suggesting, yet again, that its got non-standard boost maps and it running open loop?
I've posted the IMX and DRL maps as screenshots earlier in this thread, they are exactly identical to the 018CB OLS file posted on here years ago. So unless Audi mapped it with open loop boost...
|
|
|
|
|
Logged
|
|
|
|
|
nyet
|
|
« Reply #44 on: June 01, 2016, 04:59:46 PM »
|
|
|
No idea. Without logs, we'll never know.
|
|
|
|
|
Logged
|
|
|
|
|
