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Jeffersonc

Closed Loop Over Boosting

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I am looking into fine tuning the boost control. I am reading the help files to get a better understanding on how closed loop control and PDI works. Have a look at my log and give me an idea what area I could look into for adjustments. 
I can see that my boost integral (%DC) goes into (-).  Whats happening exactly here? 
 

now.llg

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Integral is used to remove "long term offset".  So because your boost was sitting above the target for a reasonable period of time the integral tries to correct it.  -ve integral means it is reducing wastegate DC.

After a quick look at you log I notice stage 1 is never initiated, I think this means you have probably got too much proportional trying to make up for it so thats why you get the overshoot.  

The reason for the Stage 1 not working I suspect will be "stage 2 on" setting too high.  Read note below to make sure you understand how that works:

b51pbp.png

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1 hour ago, Jeffersonc said:

Okay, if I understand correctly then perhaps try a stage 2 setting of 15kpa to start? 

Start at more like 50kpa. It looks like your wastegate DC table might need some work too.  Did you tune it in open loop first?

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In the area I highlighted below the WG DC starts at about 33% but needs to be pulled right back to about 18% before the boost stabalises on target.  So it looks like the base table has numbers of around 30 in this area, I think you can probably manipulate the base table to get it down closer to 20% faster when boost is near target rather than relying on the closed loop to do it. 

ng51m0.png

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Can you attach your tune also.  At the beginning of your log stage 3 is active before you have even reached 100Kpa so something is wrong in your settings.  That's possibly something to do with your target settings.

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Try this map below, be careful the first couple of times you boost it as I have changed it quite a bit so it may not behave as expected.  To take some variables out I have flattened the boost target table and made the Wastegate DC table more in line with what I would expect for closed loop control.

New setup.pclr

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