MS2 3.4.2 - Closed Loop Boost Control

[DisgruntledMotorist]

I've been playing with the closed loop boost control for a while now.
I can get okay results, but I would like clarification on the way the PID terms work.

The way I understand it is like this:
0 = nothing
1 = smallest amount/smallest influence
100 = largest amount/largest influence

Cheers

[DisgruntledMotorist]

Bumping this back to the top.

[Matt Cramer]

Yes, except that they top out at 200 instead of 100.

[DisgruntledMotorist]

Why doesn't closed loop boost control use the open loop "boost control duty table" as a feed forward term and apply the PID to this value?
This feature does not work with the current control strategy.

[Matt Cramer]

Why doesn't closed loop boost control use the open loop "boost control duty table" as a feed forward term and apply the PID to this value?
This feature does not work with the current control strategy.

Because the open loop table doesn't specify what boost amount the numbers will actually give you. It uses an initial value table as a feed-forward instead.

[DisgruntledMotorist]

Why doesn't closed loop boost control use the open loop "boost control duty table" as a feed forward term and apply the PID to this value?
This feature does not work with the current control strategy.

Because the open loop table doesn't specify what boost amount the numbers will actually give you. It uses an initial value table as a feed-forward instead.

Hi Matt. Maybe I wasn't as clear as I would have liked to have made myself.
I'm familiar with the control strategy, and the initial value function works well.
I believe that closed loop would be much better if the initial value table was actually a feed forward table over the entire rev range of the engine. i.e. if the PID terms were all set to 0, the controller would work just like open loop using the values in the initial value table. And with the PID terms on the duty cycle value would be altered from a calibrated initial duty cycle value, not made up as it goes along.
A maximum percentage authority from the initial value would also make the system much more robust.

[Matt Cramer]

That is currently the strategy the MS3 code follows. I am not sure if it can be back ported to MS2 or not.

[DisgruntledMotorist]

As far as I can tell the developers have no desire to continue the development of the ms2. And as I have no desire to buy an ms3 it looks like I'll have to persevere with the ms2 strategy and retune the PID for the different weather conditions of each season.

[jsmcortina]

As far as I can tell the developers have no desire to continue the development of the ms2.

This is correct. MS2 has been in a "mature" phase for a number of years and no new features are planned.

James

[rickb794]

As I understand it MS2 development became problematic as the memory space in the processor had been used up and to add anything means that something has to be removed first.

[DisgruntledMotorist]

memory space in the processor had been used up and to add anything means that something has to be removed first.

That does sound familiar, which is a shame.
I would happily give up the secondary VE, AFR and Ignition maps, nitrous control and sequential fueling (i don't use and have no intention of using these features) for more robust boost control.