Hi
having some fun with boost control, boost is higher than expected pressure. running turbosmart egate with blackbox, also have a laptop mounted just to see how wastegate works and it opens but too late to control pressure, if I set gate to be open 100% with turbosmart program pressure does not go above 130kpa. have tried different values in target base map and in activation base map tried md 10 and 85% have also tried with different values in margin target, at the attached log is with 2 different changes
2025_0403_1709.emuprolog boost control problem.emuprolog (1.1 MB)
rallyegolf pro 3-4-25.emupro .emupro (29.4 KB)
Looks like you need to invert PWM.
You have 0% as the control, and the boost doesn’t stop increasing.
I would assume the gate is closed when you have control of 0%.
in the log there are 2 pulse 1 with 85% and 1 with 15%
You must check the log to see the actual duty cycle on the output.
Every run has a 10% duty cycle when building a boost.
- The actuator duty cycle is 10%.
- The actuator DC is calculated from the control value, which is 0%.
- Control is 0% because the boost state is “Above pressure max”.
- Boost pressure at that point is 111 kPa g.
- Maximum boost pressure is set to 80 kPa g. Above that control value is set to 0% to open the wastegate fully.
You can’t just swap values in the base table to invert PWM because the boost logic assumes control 0% is the gate fully open and control 100% is the gate fully closed.
You have to enable the “Invert output” option for the actuator.
Is it intended that max target is the boost pressure you want to drive with? I expected that, so I set it to 80kpa g to see what boost did?
That is not a target.
It’s not in the target category.
You are mixing things.
This parameter is under “Control / Pressure / Activation”.
That means it’s a control activation threshold.
“Max” value is the maximum allowed boost pressure.
Boost controller will always fully open the wastegate when boost pressure is above that value.
You should set it above the maximum boost pressure you are going to be running.
okay what values would you suggest I set if I want a pressure of 250 kpa, if you would like, please show it in a screenshot
Hi
I’m still trying to figure out how the boost control works, my new issue is that boost pressure now varies up and down. I’ve tried changing the margin of target without much difference, does anyone have an idea?
2025_0421_1502.emuprolog boost varies.emuprolog (825.4 KB)
rallyegolf pro 21-4-25.emupro .emupro (29.7 KB)
Hi,
There are a few things that should be corrected.
-
MAP sensor signal
The signal is a bit noisy, and any fluctuation in the MAP value is directly translated to the injector pulse width.
Go to the sensor section and add some filtering to the MAP signal. You want a minimum filtering that gives you a mostly stable signal. This will also improve the signal quality for boost pressure control. -
Boost pressure signal
You can apply additional filtering to just the boost pressure signal. Controlling a chaotic signal is unnecessarily complicated because the boost controller will react to any change in the signal. -
Control margin
Make the margin wider to start. Those big oscillations come from the fact that you are constantly going out and into the margin range.
Set it to something like ±50 kPa. Once your boost control works correctly, you can try to tighten the margins. -
PID
Set the derivative gain to zero. It looks like the PID output is going crazy because of it. I also give the PID more room to work at the start of the tuning. Currently, your PID can only modify the base by ±20%. I would set it to ±50%, so if my base table is way off, the PID can fix it. After the base table is tuned, you can limit the PID output if you want to.
Make those adjustments, try again, and if you still have issues, post the new data.
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