DIYPNP install: inital tuning - Page 7 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 05-03-2011, 09:18 PM   #121
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Shouldn't be an insurmountable problem. An aggressive 'D' should help.

Unless there's something wrong with how the 'D' was implemented...
JasonC SBB is offline   Reply With Quote
Old 05-03-2011, 09:36 PM   #122
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,809
Total Cats: 1,780
Default

I don't let the code go all nutso.



this log shows 1 minute of idling. about 30 seconds of it is with a/c. was targeting 950rpm here. This was 5/30/15, before the new code.
Attached Thumbnails
DIYPNP install: inital tuning-idle-ac.jpg  

Last edited by Braineack; 05-03-2011 at 09:53 PM.
Braineack is offline   Reply With Quote
Old 05-03-2011, 10:12 PM   #123
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

You don't have an s/c with a large throttled volume.
JasonC SBB is offline   Reply With Quote
Old 05-03-2011, 10:13 PM   #124
Junior Member
Thread Starter
 
Join Date: Jun 2007
Posts: 411
Total Cats: 0
Default

Damn. That's how I want the idle valve to be driven, instantaneous jump! But that's the feedforward thing of MS3, not closed loop... I do believe that kind of response can be implemented in MS2/Extra using only 1 input-- a hardware input from the AC will make the ECU jump up by a set adder %. Not exactly feedforward, but better than reactive.

Last edited by Greg G; 05-04-2011 at 08:01 AM.
Greg G is offline   Reply With Quote
Old 05-03-2011, 10:14 PM   #125
Junior Member
Thread Starter
 
Join Date: Jun 2007
Posts: 411
Total Cats: 0
Default

Quote:
Originally Posted by JasonC SBB View Post
You don't have an s/c with a large throttled volume.
Nyarr. I need a hookup for the dual throttle body mod! Already have a spare throttle body here...
Greg G is offline   Reply With Quote
Old 05-04-2011, 10:07 AM   #126
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,809
Total Cats: 1,780
Default

Quote:
Originally Posted by Greg G View Post
Damn. That's how I want the idle valve to be driven, instantaneous jump! But that's the feedforward thing of MS3, not closed loop...
yeah, but what has worked well for me is manipulation of the PID code where it's not constantly trying to make adjustments. MS3 doesn't have the deadzone yet like you said you had, I would like that. I think that would help, I'd be happy with 50-75rpm window within the target, really with the way the PWM% duty jumps (at my freq it makes 0.6% jumps IIRC) you're never going to be able to hold it exactly, so the code will keep jumping back and forth and accomplish nothing.

The way mine is set makes it able to reach my target with stereo at full blast, a/c running and headlights on. Like I said before, starting at 0/0/0 I like to turn on everything, then find the lowest I value that can reach my target. Then I start bumping up P and at the same time start causing the idle to get upset (blips, a/c cycling, etc) and see how it reacts and tracts. If I start adding too much P even with a **** ton of D, it reacts too quickly and starts a cycle of oscillation.

I got new firmware yesterday with the mario enhancements written into the MS3 PID code, so I had to retune. I ended up at 5/17/40.

I was talking to Ken about it and he said he typically ends up with more P than I, but anytime I try it it overreacts and can't idle steady. One thing he suggested to me was enlarging the min-max rpm zone to cut down the sensetivity of the code, but that only allowed 2 more points of P. It could be our slow idle frequency or something, but I've been happy with how it's running my car.

I could try to turn of the a/c idle up code and see what happens when my a/c turns on. I had it that way when I first installed MS3, as the a/c code wasn't implemented yet. I had a little dip, the CL code brought the idle back up and all was well again. For my setup, P still reacts fast enough, even set so low, and the high D keeps it in check.

Also notice in my log I posted that since the idle valve holds steady, the AFRs now have the most effect on the idle speed.
Braineack is offline   Reply With Quote
Old 05-04-2011, 10:31 AM   #127
Junior Member
Thread Starter
 
Join Date: Jun 2007
Posts: 411
Total Cats: 0
Default

Thanks! What are your Min/max rpm settings? I remember reducing the max, and the valve just stopped responding

Next time you talk to ken, remind him to port the "idle duty adder on hardware trigger" code from ms3. He did tell me it's doable...
Greg G is offline   Reply With Quote
Old 05-04-2011, 10:46 AM   #128
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,809
Total Cats: 1,780
Default

Yeah but I want him to do my stuff first


I have it set to 700-1500RPM, was 775-1300RPM.
Braineack is offline   Reply With Quote
Old 05-04-2011, 10:54 AM   #129
Elite Member
iTrader: (1)
 
Join Date: Jun 2006
Location: Warrington/Birmingham
Posts: 2,658
Total Cats: 39
Default

Quote:
Originally Posted by JasonC SBB View Post
Shouldn't be an insurmountable problem. An aggressive 'D' should help.

Unless there's something wrong with how the 'D' was implemented...
Possibly, seeing as Ken states you should never need any 'D'....
richyvrlimited is offline   Reply With Quote
Old 05-04-2011, 12:15 PM   #130
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Perhaps he never tried to do idle on an s/c setup with an intercooler.

I will repeat.

P and D work together. D allows big P. Together they make the loop react quickly.

I have been doing control systems for over 20 years in my day job. Properly implemented, D allows a large P; together they allow fast response with little or no overshoot.

Look what 'D' did for my AEM boost control. They didn't have any 'D' in it so I built a circuit just to add it in. I used to get as much as 5 psi of overshoot - without my D circuit, I had to make boost control very slow in order to prevent overshoot. Now I get 0-0.5 psi of overshoot.


See logs below. This is with a 5 psi (133 kPa) wastegate can. The D circuit modifies the duty cycle going to the solenoid, so you won't see its action in the duty cycle trace.

Top red trace is MAP. Left: no 'D'. Right: with 'D'.


JasonC SBB is offline   Reply With Quote
Old 05-04-2011, 12:30 PM   #131
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,809
Total Cats: 1,780
Default

See I tune EBC PID different. I start with a high P and lower until when I spool I reach my target. Then I add I to keep the target held to redline. I add D term to reduce any oscillation/overshoot and tweek the other values as need. My boost curve is baller status.

this was my last dyno pull:


Last edited by Braineack; 05-04-2011 at 12:41 PM.
Braineack is offline   Reply With Quote
Old 05-04-2011, 12:41 PM   #132
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

The MS boost control PID algorithm is also a bit oddball.
Do you have boost control logs at full boost at say 5500 RPM, WOT, then you lift completely, and get back on immediately, just like the upper right hand trace I show above? That used to be where I would get the most violent overshoot.
JasonC SBB is offline   Reply With Quote
Old 05-04-2011, 12:45 PM   #133
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,809
Total Cats: 1,780
Default

No, but I could later. I do have logs of throttle maniuplation while in boost and it handles it perfectly.
Braineack is offline   Reply With Quote
Old 05-04-2011, 03:55 PM   #134
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,809
Total Cats: 1,780
Default

just took a log, if anything it just proved I have too much D. no overshoot whatsoever, map log looks exactly like yours.
Braineack is offline   Reply With Quote
Old 05-04-2011, 04:38 PM   #135
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Might be fun to reduce D by 30-50% and see effect on WOT-lift-WOT.
JasonC SBB is offline   Reply With Quote
Old 05-04-2011, 04:58 PM   #136
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,809
Total Cats: 1,780
Default

I know I added the D to remove a bit of oscillation I had, but I need to retune it completly, they changed the code a little and I'm not quite hitting my boost target anymore.
Braineack is offline   Reply With Quote
Old 05-05-2011, 07:36 AM   #137
Junior Member
Thread Starter
 
Join Date: Jun 2007
Posts: 411
Total Cats: 0
Default

Been a bit busy these past 2 days. Trying to get a semblance of feedforward, I did 3 things:

1. plumbed in the EGR solenoid for added air
2. added a time delay relay to the ground signal to the AC relay (1J). EGR solenoid and AC fan are not delayed.
3. wired the AC out signal (1J) to PE1 to enable table switching. Table 3 is the same except for a higher spark advance at idle. Previously, I had used idle advance, which was still reactive and had a 700 ms delay from AC on to spark advance, and occasionally dropped out during oscillations. Now spark advance is instantaneous and unaffected by oscillations.

Spark tables:
Name:  55dualtable.png
Views: 4
Size:  187.1 KB

Results:
Name:  55tableswitch-1.png
Views: 4
Size:  151.2 KB


The car is much more sedate in reacting, smoother if you will. There's still a dip and oscillation. The air solenoid is good for 100-150 rpm. Maybe I should also delay the AC fan? It seems to be blunting the effect of the air solenoid. On the other hand, separating it from the AC compressor "softens the big blow".

Was too tired to dial in the closed loop settings. Also need to figure out the correct delay interval for the AC clutch. Too much delay and the closed loop wrestles the idle back down. I'm assuming I should time it in such a way that the AC clutch engages at the peak of the RPM 'hill" from the added air. Will study the logs first. And rest the brain
Attached Files
File Type: msq 2011-05-05_18.17.53tableswitching.msq (79.6 KB, 63 views)
File Type: msl 2011-05-05_16.43.07p8i30d10.msl (191.6 KB, 66 views)

Last edited by Greg G; 05-05-2011 at 09:21 AM.
Greg G is offline   Reply With Quote
Old 05-05-2011, 09:45 AM   #138
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,809
Total Cats: 1,780
Default

I decided I now agree with Jason with too much I and not enough P.

I completely retuned mine and was getting closer to 10.2 | 5.8 | 3.2. But it still needs fine tuning.

With so little P, you really take the spring away from the code to react to the rpm change and get to the I point. Since I do have the feedforward code, I didn't need as much because the only other time I'd need to react to something, is headlights going up. This has worked well for me, only because I never needed more.

I started tuning my code without feedforward active and its completely changed how I went about it. I was basically the idle up adder as my P value. You dont need as much I if you use P to get drive you to the target faster. Some D should just prevent the P code from overshooting that target.



Are you saying you have that code now? or were you just able to delay the compressor onset? I would time it better so the idle speed increases just as the compressor is turned on and would otherwise cause them to drop.
Braineack is offline   Reply With Quote
Old 05-05-2011, 10:07 AM   #139
Junior Member
Thread Starter
 
Join Date: Jun 2007
Posts: 411
Total Cats: 0
Default

Quote:
Originally Posted by Braineack View Post
Are you saying you have that code now? or were you just able to delay the compressor onset? I would time it better so the idle speed increases just as the compressor is turned on and would otherwise cause them to drop.
No change in code. 3.1.1 'mariob v5'

I have an external adjustable time delay relay intercepting the output from 1J. So the purge solenoid and the spark table switch occur ahead of the AC clutch engagement.

So it looks like I have too much delay on that graph? Hard to time it on the car, looking at the log, its about 3 seconds. Will adjust that, then the closed loop idle. The only thing left is to convince Ken to give me that instant idle duty response on a hardware trigger. Hmm, if that happens, then I'd have to drastically reduce the delay. Now I have to ask for a delay in the idle up from the hardware trigger, to match the external delay on the compressor

Last edited by Greg G; 05-05-2011 at 10:29 AM.
Greg G is offline   Reply With Quote
Old 05-05-2011, 10:27 AM   #140
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,809
Total Cats: 1,780
Default

how much is the delay? IIRC, I'm shooting the pwm% up 5% on a 500ms delay.
Braineack is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM
Are my coils failing? viriiguy General Miata Chat 5 09-28-2015 08:39 PM
Missing/knock at idle, can someone point me in the right direction? Mikel MEGAsquirt 4 09-28-2015 05:46 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 04:06 AM.