Closed loop boost control starting numbers
04-01-2016, 02:14 AM
#1
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Closed loop boost control starting numbers
I've tuned open loop, ran this for 4 years. Max boost I look for is 12psi
Interested in trying closed loop but after several failed attempts thought it was worth asking for help.
I've a ms2 rev enhanced ecu, FM2 turbo set up on a 1.8.
Does anyone running a similar set up on closed loop boost control have a basic set of numbers I can start on ?
Interested in trying closed loop but after several failed attempts thought it was worth asking for help.
I've a ms2 rev enhanced ecu, FM2 turbo set up on a 1.8.
Does anyone running a similar set up on closed loop boost control have a basic set of numbers I can start on ?
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04-01-2016, 07:48 AM
#3
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Ok, but ......
Is there at least a starting point?
PID values ?
I had these numbers but they were from another guys set up and the car keep overboosting cutting.
My open loop map is fairly good so I figure if I can get close with PID and start dropping P until it stops over boosting I'm heading in the right direction.
P=145
I=40
D=100
Do you start at 0-0-0 or 100-0-0 or 100- 50-0 ?
Is there at least a starting point?
PID values ?
I had these numbers but they were from another guys set up and the car keep overboosting cutting.
My open loop map is fairly good so I figure if I can get close with PID and start dropping P until it stops over boosting I'm heading in the right direction.
P=145
I=40
D=100
Do you start at 0-0-0 or 100-0-0 or 100- 50-0 ?
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04-01-2016, 11:33 AM
#5
Boost Czar
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I had these numbers but they were from another guys set up and the car keep overboosting cutting.
P=145
I=40
D=100
Do you start at 0-0-0 or 100-0-0 or 100- 50-0 ?
P=145
I=40
D=100
Do you start at 0-0-0 or 100-0-0 or 100- 50-0 ?
start at 100-0-0.
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04-01-2016, 12:08 PM
#7
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So here's what I had my settings at for open loop control
<br >This is now my closed loop, just changed the PID settings to my starting numbers. Am I right in that's all I need to change to get started ?
<br >
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04-02-2016, 01:40 PM
#8
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Followed the guide below with settings
P = 100
I = 0
D = 0
Held it at 2000rpm Wot runs in 3rd
No matter what I lowered P to nothing changed. Fairly slow spool up gets the wastgate.
The boost duty figure is changing but the same with any PID number.
Followed these guidelines:
Set Integral and Differential Gains to 0% - To make tuning the Proportional gain easier, set the Integral and Differential gains to 0%.
Set Proportional gain to 150% and slowly lower - While tuning Proportional gain, higher numbers mean slower boost climb and lower final boost. For safety, start with a very high gain (150% should be sufficient). Find the RPM that typically spools quickly, and fully and quickly depress the accelerator. Note how much boost is reached. If boost overshoots the target, increase the Proportional gain. Otherwise, reduce the Proportional gain and try again. Do this until boost reaches the target with little or no overshoot.
Switched back over to open loop and all back to normal working from my OL boost control duty table spools upto target 10psi
P = 100
I = 0
D = 0
Held it at 2000rpm Wot runs in 3rd
No matter what I lowered P to nothing changed. Fairly slow spool up gets the wastgate.
The boost duty figure is changing but the same with any PID number.
Followed these guidelines:
Set Integral and Differential Gains to 0% - To make tuning the Proportional gain easier, set the Integral and Differential gains to 0%.
Set Proportional gain to 150% and slowly lower - While tuning Proportional gain, higher numbers mean slower boost climb and lower final boost. For safety, start with a very high gain (150% should be sufficient). Find the RPM that typically spools quickly, and fully and quickly depress the accelerator. Note how much boost is reached. If boost overshoots the target, increase the Proportional gain. Otherwise, reduce the Proportional gain and try again. Do this until boost reaches the target with little or no overshoot.
Switched back over to open loop and all back to normal working from my OL boost control duty table spools upto target 10psi
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04-04-2016, 02:25 PM
#12
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Then started tweaking I and went to 10.05.0 and it overshot
Went to 10.02.0 and it overshot
Went to 10.01.0 and it didn't seem to change anything
Ended up back at 10.0.0
Log attached
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04-04-2016, 04:53 PM
#14
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Logging - Can anyone confirm if my goal is to get my MAP to be matched with the my Boost Target, as much as possible. If that's correct how close should I be aiming for, whats achievable ? Thanks
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06-08-2016, 12:49 PM
#15
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Brain - can you elaborate on this:
Every PID controller I've ever tuned (I work in controls for a living) uses P gain such that it is being multiplied by the instantaneous error Kp*(target boost - actual boost) for this case. Increasing P in all the other controllers I use should INCREASE boost response (more adjustment for a given error should result, ultimately, in overshoot and oscillation conditions)...Why is it reverse in this case?
I have an email out to Matt at DIY about it and so far he has told me it is a PID Type C controller but I'm not finding much on it, even in the source code!
Any help is appreciated here.
higher numbers mean slower boost climb and lower final boost.
I have an email out to Matt at DIY about it and so far he has told me it is a PID Type C controller but I'm not finding much on it, even in the source code!
Any help is appreciated here.
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09-26-2017, 08:53 AM
#16
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Got back onto this after a year hill climbing the car in England.
Found an old thread from Braineack and did the following:
1) Ran some WOT runs in 2nd gear with no boost control to get the wastegate pressure which on mine is 9psi (approx 165 MAP)
2) Set the boost control to closed loop and the rate to 40
3) Set the boost target table to a higher pressure than wastgate - 185 MAP (approx 12 psi)
4) Set P.I.D to 200.0.0
5) Ran 2nd gear pulls nice and steady and allowed boost to build the revs
6) Checked the log to see if the MAP was getting close to target boost.
7) Repeated steps 5 & 6 and reduced P until it overshot slightly.... on mine it was 11.0.0
8) Next step I believe is to increase I until it maintains the boost target better, oscillation to be tuned out with D. Will try again at the weekend.
What I like about the open loop is that it appears to give a consistent boost level through the gears and doesn't fluctuate by +2 psi dependent on ambient temps.
Previously if my target was 14psi I had to tune this for 4th gear pulls which gave me about 11psi in 2nd gear. Seems not to vary with closed loop.
Found an old thread from Braineack and did the following:
1) Ran some WOT runs in 2nd gear with no boost control to get the wastegate pressure which on mine is 9psi (approx 165 MAP)
2) Set the boost control to closed loop and the rate to 40
3) Set the boost target table to a higher pressure than wastgate - 185 MAP (approx 12 psi)
4) Set P.I.D to 200.0.0
5) Ran 2nd gear pulls nice and steady and allowed boost to build the revs
6) Checked the log to see if the MAP was getting close to target boost.
7) Repeated steps 5 & 6 and reduced P until it overshot slightly.... on mine it was 11.0.0
8) Next step I believe is to increase I until it maintains the boost target better, oscillation to be tuned out with D. Will try again at the weekend.
What I like about the open loop is that it appears to give a consistent boost level through the gears and doesn't fluctuate by +2 psi dependent on ambient temps.
Previously if my target was 14psi I had to tune this for 4th gear pulls which gave me about 11psi in 2nd gear. Seems not to vary with closed loop.
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