Jump to content

Closed loop boost control help


434josh

Recommended Posts

Can someone look over this log file and included map and suggest some PID changes to stop the boost target overshoot?

I can see them all working in the log - Integral steps on and starts reducing duty but it plateaus right when target is achieved and doesn't stop the overshoot.

Log 2019-03-8 9;37;58 pm.llg Ford 363plus ve smooth.pclr

Link to comment
Share on other sites

I've only had a very quick look but it seems a bit odd on the 2nd pull that the ECU has pulled 6% DC out by the end when you lift off but the boost was still climbing.  I guess thats just more inertia to the turbos I typically see.

Stage 2 is P & D only, Stage 3 is P & I only.  You can see when it initially switches to stage 3, integral is still positive so it adds to the DC for quite some time.  I would try reducing the "stage 3 on" value to 10kpa and maybe extend the stage 3 delay for a little longer.  This will mean it will stay in PD mode for a little longer so that integral doesnt end up adding DC just before it reaches target.  

I suspect you may need more P too so it is a bit more reactive but try the above first. 

Link to comment
Share on other sites

I've also had a look, and have some comments in addition to Adam's...

On 3/9/2019 at 9:27 AM, Adamw said:

ECU has pulled 6% DC out by the end when you lift off but the boost was still climbing

Would it benefit from tuning the wastegate table in open loop so that the control system has less corrections to do?

 

image.png

Link to comment
Share on other sites

On 3/10/2019 at 11:09 AM, Tim D said:

I've also had a look, and have some comments in addition to Adam's...

Would it benefit from tuning the wastegate table in open loop so that the control system has less corrections to do?

 

image.png

In open loop the boost is solid at 17 psi. Just a lot slower getting up to peak. 

 

So i did what Adam suggested and its much much better. Doesn't overshoot like it was but does oscillate from 205-211 kpa throughout a pull and is enough it makes the rpm fluctuate a bit.

Ignore the stupid high IAT...forgot to activate my meth injection system.

642 pass.llg

Link to comment
Share on other sites

1 hour ago, Adamw said:

What have you got for P & I gains in that run?  One of them is too high, Im leaning towards too much I.

I is the same as the original log/tune file above. 

I only changed the stage 3 to 10kpa, added some D and lowered target from 220 to 210ish kpa. 

I was much more active this time so I will try lowering. 

All in all this was so much better than before and stayed within 1-2 psi of target. This netted my fastest 1/8 mile pass to date and on less boost. 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...