Feature Request: PID delay for Closed Loop Boost

Testing and development of Megasquirt 3

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cj.surr
Helpful MS/Extra'er
Posts: 68
Joined: Fri Jul 29, 2016 4:28 am

Feature Request: PID delay for Closed Loop Boost

Post by cj.surr »

A specified delay before enabling boost PID control after going to the initial boost duty. When a lower initial boost duty is necessary, the WG takes a significant amount of time to make the transition from 100% duty position to 25% duty position (for example). Without a delay, PID control starts to correct (add duty) before the initial duty WG stroke is achieved and the turbo is still spooling- the result is a boost spike. This can be tuned out with less sensitivity, but the boost control effectiveness suffers otherwise, when higher sensitivity is needed. Adding this delay feature would greatly help boost control on setups with fast spool and touchy WG setups.
93supercoupe
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Location: New Haven, Ct, USA

Re: Feature Request: PID delay for Closed Loop Boost

Post by 93supercoupe »

Agreed. Right now it's a fine line between adjusting the kpa delta. Too much delta results in over boost from not giving it enough time and too little delta also will spike due from the PID adding dc during spool.
BootlegTuned
aidandj
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Re: Feature Request: PID delay for Closed Loop Boost

Post by aidandj »

Also have this issue.
cj.surr
Helpful MS/Extra'er
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Joined: Fri Jul 29, 2016 4:28 am

Re: Feature Request: PID delay for Closed Loop Boost

Post by cj.surr »

Another, possibly more effective, option is waiting to engage PID control until MAPdot has fallen below a specified value, indicating that boost has leveled off. This would take care of variability in wastegate response due to RPM, load, boost target, IAT, etc.

That also brings up initial duty scaling based on IAT, which I think would be very helpful for 4 season cars. I am updating my initial duty table based on the season now, which is inconvenient and still mostly ineffective.
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