dx4picco Posted January 18 Report Share Posted January 18 I have a question that I can't fin an answer. until now I only ran open loop boost control on my cars. my dad's subaru now has a vf36, very sensitive turbo, to climatic condition changes. I'm looking to start with close loop. until now I've always ran boost by pedal style of control so you have a very linear control of the car. now my trial setup looks like this: https://drive.google.com/file/d/1lV4QTTteAPNlO6UGKWto5SWH9AHwwamX/view?usp=sharing basically I was running similar parameter, with gains of 0 and only a boost target in my upper row. now I added some base parameters and had to fill target table aswell. my question would be, is there a smart way of doing things so that the closed loop is effectively working only above 70% APS? because high boost target will get me stuck in stage one and low boost target puts me in stage 3 very quickly. I don't need closed loop at lower boost levels, only for the upper 2 rows lets say How would you go about it? NB: also, i'm not sure I understand the difference between both base DC mode (2 or 2 and 3) Quote Link to comment Share on other sites More sharing options...
Adamw Posted January 18 Report Share Posted January 18 You can vary the target with APS as you have set up. Set up the control so that it only moves into stage 2 when you are somewhere close to the minimum achievable "spring pressure boost". The lowest value anywhere in the target table should also be the same "minimum achievable spring pressure boost". In stage 2 the duty cycle will still mostly be coming from the wastegate DC table just like it did in openloop mode but with corrections added depending on how far off target you are. 2 hours ago, dx4picco said: NB: also, i'm not sure I understand the difference between both base DC mode (2 or 2 and 3) In stage 3 the actual DC value applied to the wastegate comes from "Base DC" + Proportional correction + Integral correction. If the base DC mode is set to "Stages 2-3" then the "Base DC" part is coming directly from the base DC table. If set to "Stage 2 only" then the "Base DC" part is fixed at the last base DC that was being commanded from the table when you left stage 2. I would suggest base DC mode "Stages 2-3" based on the shape of your base DC table. You have a big change in your base DC table between 5&6000RPM so likely closed loop will need to do less work with the variable base dc coming from the table through the whole rev range. I dont think I have ever needed to use the "Stage 2" base DC mode but I suspect there are applications where there is some other factor involved that causes the DC required to reach target quite variable, but once you are on target the control requires less variation. dx4picco 1 Quote Link to comment Share on other sites More sharing options...
dx4picco Posted January 19 Author Report Share Posted January 19 8 hours ago, Adamw said: You can vary the target with APS as you have set up. Set up the control so that it only moves into stage 2 when you are somewhere close to the minimum achievable "spring pressure boost". The lowest value anywhere in the target table should also be the same "minimum achievable spring pressure boost". In stage 2 the duty cycle will still mostly be coming from the wastegate DC table just like it did in openloop mode but with corrections added depending on how far off target you are. In stage 3 the actual DC value applied to the wastegate comes from "Base DC" + Proportional correction + Integral correction. If the base DC mode is set to "Stages 2-3" then the "Base DC" part is coming directly from the base DC table. If set to "Stage 2 only" then the "Base DC" part is fixed at the last base DC that was being commanded from the table when you left stage 2. I would suggest base DC mode "Stages 2-3" based on the shape of your base DC table. You have a big change in your base DC table between 5&6000RPM so likely closed loop will need to do less work with the variable base dc coming from the table through the whole rev range. I dont think I have ever needed to use the "Stage 2" base DC mode but I suspect there are applications where there is some other factor involved that causes the DC required to reach target quite variable, but once you are on target the control requires less variation. that's clear now for the difference! in regards to the first paragraph, it doesn't feel right to me, if that makes sens? lets say at 4000 rpm 35% tps, having a boost target of 150kpa as you wrote (wg spring is 0.5 bar) would mean I'm in stage 1 with very high DC at first then stage 2 will try to increase boost at 150 which is lower when openloop, and this is not wanted as I would then get a boost surge when it should actualy be between 0 and 15% duty (solenoid acts only after 15%). Would that then make sens to have a 0 P and 0 D to be kind of openloop in those area and a stage 3 limit to never be reached? and keep the I gain for stage 3 at higher pressures to hit target boost? Or maybe I'm lost in my analysis Quote Link to comment Share on other sites More sharing options...
Adamw Posted January 20 Report Share Posted January 20 On 1/19/2024 at 9:07 PM, dx4picco said: would mean I'm in stage 1 with very high DC at first Stage 1 can be any DC you want, typically you have it as high as possible to reach target as quick as poss, but if you dont want that then fix it to something lower. Quote Link to comment Share on other sites More sharing options...
dx4picco Posted January 22 Author Report Share Posted January 22 Made some test yesturday, Integral is making some crazy things was down to 0.05 and still seemed too high. will tryat 0.02 with higher P and D later this week. Quote Link to comment Share on other sites More sharing options...
Adamw Posted January 22 Report Share Posted January 22 Yeah, typical starting point for I seems to be around 0.04 for me. Quote Link to comment Share on other sites More sharing options...
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