Closed Loop boost control Help.

Mxp_57
Posts: 18
Joined: Fri Apr 03, 2009 9:17 am

Closed Loop boost control Help.

Postby Mxp_57 » Fri Nov 06, 2009 5:41 pm

Hi, i am just looking for some help in order to set the closed loop mode.
I've been searching everywhere in the forum in manuals etc and i'm quite surprised to see that people on the forum have to give up using closed loop boost control because nobody is able to help, to see that the HELP in the software is not up to date with what's in the boost control window. And that there isn't any proper manual for the interceptor and the available manual doesn't even show once the word closed loop...

I'm not novice with cars, i'm a DIYer but i'm lost here. So if someone could explain me the different settings in the digital output window and how they affect boost that would be great, for me and for a lot of people on this forum.

So for example the PID, what is boost thres? the boost period etc etc...

Thank you very much!

Cedric

PS: i have a celica gt4 and i'm using the haltech solenoid.

Mxp_57
Posts: 18
Joined: Fri Apr 03, 2009 9:17 am

Re: Closed Loop boost control Help.

Postby Mxp_57 » Sat Nov 07, 2009 11:14 am

I found this pretty useful. http://files.haltech.com/downloads/plat ... st_control

But there is still two thing that confuses me:

-In what unit is Boost Thres (Psi, %, kpa??)
-Is boost period the same as solenoid frequency (20~30Hz) How come it is in ms?

Cheers

Mxp_57
Posts: 18
Joined: Fri Apr 03, 2009 9:17 am

Re: Closed Loop boost control Help.

Postby Mxp_57 » Tue Nov 10, 2009 10:07 pm

Anybody? :oops:

vosadrian
Posts: 25
Joined: Thu Sep 10, 2009 9:43 am

Re: Closed Loop boost control Help.

Postby vosadrian » Thu Nov 12, 2009 3:45 pm

Boost threshold is the amount of boost before the setpoint (from boost map with trims) that the closed loop operation starts. So if threshold is 5psi, and setpoint is 15psi, the closed loop starts at 15-5=10psi. Below that, the output is 100% to get to boost setpoint asap. Once it hits the threshold the closed loop starts with a start duty that is set in the start duty table (for different boost levels).

Ideally you set the start duty to the duty required to run that boost. This allows the closed loop to start with close to the right duty cycle. Then you set the threshold so that it has enough time to get control without a boost spike. If you set it to 1 psi, you will get a boost spike, as the wastegate will not have enough time to move from fully closed to the right postion for control. This can depend on the setup. 5 psi is a good starting point.

Then set the PID paramters for good stability. Initially set them all to zero (which is effectively open loop mode and it will just run the start duty all the time), and set the start duty map so the boost run matchs the set point in the boost map. Then start adding in proportional. Add it in 0.1 increments. Get it as high as you can whilst still maintaining stability. At some point it will start to osciallate as it is too high. Back it off and then some, as it may still oscillate on a cold night. Then do the same with I (leaving P where you set it). Add it in slowly in smaller increment (0.01-0.02 increments) until it becomes unstable and then back it off (and then some for stability in cold weather). You can do the same with D also, but I generally leave D at zero, as it can cause strange behaviour if you have a noise map sensor signal.

If you get it setup right, you should get nice stable boost control that is very repeatable in a wide range of atmo conditions.

-- Adrian

Mxp_57
Posts: 18
Joined: Fri Apr 03, 2009 9:17 am

Re: Closed Loop boost control Help.

Postby Mxp_57 » Fri Nov 13, 2009 9:42 am

Thank you so much!! :wink:

Just one last question boost period is the frequency of the solenoid. in ms no?
So the haltech solenoid is 20-30Hz, os 1/20= ms ?
Is it better to put 20hz or 30 hz?

Cheers!

vosadrian
Posts: 25
Joined: Thu Sep 10, 2009 9:43 am

Re: Closed Loop boost control Help.

Postby vosadrian » Fri Nov 13, 2009 2:38 pm

Yes period is in ms which is 1/frequency. I normally use 50ms (20Hz).

-- Adrian

jasaircraft
Posts: 636
Joined: Sat Feb 16, 2008 4:17 pm
Location: Santa Cruz Bolivia
Contact:

Re: Closed Loop boost control Help.

Postby jasaircraft » Sun Oct 24, 2010 10:11 am

anyone know the frequency of the 99 sti boost control solenoid? in hertz and in ms???
and if possible the frequency of their earlier (1998 and earlier) idle valves?
Making people fly!


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