Hi, i would like to discuss if you can add some settings or how to deal with these. I met these situations on PRO and V3.
During cruising i would like to have wastegate closed(due exhaust noise, flapper rattle and start of spool) but not want to force EWG servo to end position for a long time. My idea is to have adjustable margin treshold, to switch between baseDC(not zeroDC) and fullDC according rpm vs boosttarget for example.
When turbo starts to make some backpressure at high boost, i notieced PID control of EWG position doesnt able to adjust DC fast enought to stay on target. It can be little overcome by false adding more boost DC, but… What about simple small ewg DC correction table rpmVSactualboost ?
And last thing, its also on standard pneumatic boost control. The margin below target treshold, make it again as a table vs RPM, to better balance Integral windup at low rpm and boost spiking at high rpm.
Hi,
We can discuss it, but first you have to provide data supporting your claims.
Post a project and log file, and point us to a timestamp with the issue you are describing.
You can achieve that by setting a high boost target at cruising.
I don’t see how it’s different from changing the margin.
What type of EWG? With or without a return spring?
Please post the data as mentioned above.
Again, let’s see it first.
Before we start talking about making changes to the software, we have to confirm that we can’t tune it with the tools available currently.
Thanks. Im sending log from V3 as its latest car i work with.
Actuator is Mahle, it has weak return spring.
Margin is making switch between zeroDC and fullDC(on V3, im not sure on PRO now to be honest, as its was on racecar so i set boostcontrol minimum RPM to 0 and minimum kpaG also 0, it will shut WG immediately when i saw positive boost target and then hold forever) . Idea is to be able set WG almost close during cruise are, for example 95%. Its also quicken and smooth out transient into low boost in part throttle acceleration, not off-on switch.
At 0:20 is the pull, where you can see EWG do not follow the target position at high rpm. EWG dc start to rise of course(logged PID is for boost control). Yes, it start to be on the limit of the mechanical force of the actuator, but it can be better.
At 2:00 are dyno pulls on lower boost settings, i know its not fully perfect base DC but also not completely off…margin is -30kpa and you can see the trend, when target is lower, margin is turning off in area where boost is rising slowly so there is more and more time for Integral windup and resulting in overshoot.
I already responded to that.
Change the boost target at cruise to a high value.
Wastegate will be closed to try to generate boost.
Ok, I see what the problem is.
In EMU PRO, we have the option to select EWG with or without a return spring.
When the EWG with spring is selected, there is an additional table with the base DC for EWG.
That spring mode for EWG is missing in Black V3.
For now, you can try more aggressive PID gains for EWG.
How did you conclude it’s an integral windup?
Because there is no integral windup at that point, so that’s not the reason.
You can check the channel “Monitored I term”.
The highest value during that pull was less than 1.
That means the integral part changed the EWG position by 1%.
The solution to that is opening the wastegate more at that point with the “Duty cycle feedback” table.
But thats what i dont want during cruise, to save EWG motor, but also do not want lagging response due open WG completely. If in PRO margin is switching from basedc to fulldc, its ok and “issue” is only in V3 then.
The EWG integral term was already pretty high at 30 (32 is maximum) and yes i rised it a bit only due this.
Sorry i may not call it integral windup, just simply P+I have more time to feed boost DC well over base to pronounce overboost. As you can see, because low rpm spool is exponencial, with 1.5bar boost target, time since boost reaching margin treshold to target boost is only cca 0.3sec, but with boost target of 0.6bar the time is almost 5x times longer (1.5sec). At higher RPM the difference will not be that high. So some compensation will be nice to have.
Sorry, I missed the part where you said you don’t want it fully closed, but almost closed.
My solution to achieve this would be a table with the DC when the boost is under the margin.
Currently, when the boost pressure is under the margin, the controller outputs the max DC/max position target to achieve the best spool. With a table, you could set max DC at WOT and 90-95% at part throttle. This could also be used for a better transition from the spool to hitting the target.
We will discuss this.
I was looking only at the 2:00 pull, and it was 1.2 bar.
I see that at 0.6 bar, there is too much correction from the PID.
I think the solution would be a table for the margin value based on the boost target. For a high boost target, the margin can be bigger to have time to react, and for a low boost target, the margin can be tight to limit the PID windup during slow spool.
To sum up:
Base DC for EWG with spring.
Table with DC/Target when under the margin, based on APS, and maybe boost target error.
Table instead of a single value for the margin below, based on the boost target.
This should solve all your issues and allow for precise control at multiple boost levels.
You mean without spring isnt?(in PRO), to be able compensate backpressure for both types? And is this table only difference in type setup or is also something on backround? => can i temporarily enable it now on car where is without spring type calibrated now?
Maybe it can be just as simple as add another treshold condition for activation maxDC margin function, the boost target. If driver will cruise, just slightly accelerate but target demand will be under boost target gkpa = baseDC. And when accelerate more, target will rise over treshold…ecu compare if is under margin and = maxDC. Or simply allow “negative” gkpa taget in target table, so it can be filled by lower values to suit margin as needed…but it can be messy.
Table rpm vs boost target? More rpm, less this situation occur and maybe it can make boost spikes at high rpm on small boost target conversely. But i know you dont want waste resources on another 2/3/4D table.