Low PW Compensation

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blakebonkofsky
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Low PW Compensation

Postby blakebonkofsky » Wed Jun 07, 2017 6:25 am

Noticed on the ID2000 datasheets, they list Low PW Compensation numbers, but I have not figured out a way to configure the Elite to use these. I understand the numbers that are listed in the datasheet (I think), but cannot find a pulsewidth variable to set as the axis for the generic correction. If I used a single injector output pulse width, that would base corrections for all 8 injectors off of a single injector. While 99% of the time, this may be fine, I wouldn't think it would be ideal. Is there a variable I'm missing that would be suitable for this? Or is this only something that would be possible when using injection time for mapping instead of VE? I wouldn't think ID would list the data if there was no way to use it...

LowPWComp.png

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Mattias
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Re: Low PW Compensation

Postby Mattias » Thu Jun 08, 2017 2:21 am

Hi, I did like this. And I don't have any individual cylinder corrections.

Low pw.JPG

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blakebonkofsky
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Re: Low PW Compensation

Postby blakebonkofsky » Thu Jun 08, 2017 9:56 am

Does that work correctly like that? I would think it would get stuck in a loop? Like, Inj pulse of 1.0ms, it adds ~5%, then the pulse is 1.05, where it would again add another ~5% and so on... I don't know exactly how the final pulse is calculated, it would just seem like it would cause a loop problem. Maybe I'm just reading too much into it...

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Mattias
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Re: Low PW Compensation

Postby Mattias » Fri Jun 09, 2017 9:01 pm

I don't think I'm down that low in pw that it's actually used, but I will check.

But I see your point. But for the low pw comp to work it should be based on actual pw with all compensations added, think this needs some explaination by Matt :)

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HaltechMatthew
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Re: Low PW Compensation

Postby HaltechMatthew » Wed Jun 14, 2017 11:26 am

The low pulse width compensation exists to cover for conditions where you are commanding less injection time than the time it takes for the pintle to open fully. In other words, more injection time than the dead time, but not enough to have the injector open fully so the pintle is floating. So when you ask for a certain amount of fuel you don't get what you asked for, and a tiny amount of extra time is needed so you do get the correct amount of fuel.

In most instances this does not impact the tuning or is never noticed, but it can if you have a small engine size with very large injectors and very light load (decel). Due to the complexity and, in all honesty, most people never tuning to this fine a level, it was just simply not added so as to remove confusion for those who do not understand what it is for. Case-in-point, if you did not receive this data from the injector supplier would you have ever tried to find these values? Most of the time the close loop control covers this anyway.

At the moment it will not work because there is no ECU channel that shows the total injection time minus the dead time (actual delivered injection time). You can view the volume channels which do calculate the amount of fuel that is commanded to be sent in (part of VE calculation) and possibly map against this, but it does not reference RPM.

There has been a request for the actual delivered injection time channel to be made available so that this low pulse width information can be entered. No ETA, but it is in the list.

Spadam9
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Re: Low PW Compensation

Postby Spadam9 » Sun Jun 18, 2017 10:26 am

I have an EJ257 with id 1300 injectors so do get in to the low pulse width zone in normal driving even on e85. I mapped mine with the individual cylinder generic fuel comps and the ID provided data. It has definitely made the car drive so much smoother at light load high rpm and idle smoother (more like the stock one which has LPW comps). Interesting what Matt said that dead time is not factored in to each injector out put time and it wont work, may be if I had the correct channel with dead time factored in it would work better. In my opinion already with my trial fix it has improved drive ability alot.

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abraxxa
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Re: Low PW Compensation

Postby abraxxa » Sat Jul 22, 2017 5:00 am

I have ID1000 and found the low pw comp info on their website for the Haltech Elite so I assumed there must be a way to configure this.
What I did is to enable Fuel / Generic 1 Correction, used 'Injector Output 1 Injection' for Axis 1 and entered the ID1000 supplied values.

@Matt: so this doesn't do what I expected and should be removed?

Spadam9
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Re: Low PW Compensation

Postby Spadam9 » Sun Jul 23, 2017 11:40 am

Here are the sheet you are talking about: http://help.injectordynamics.com/suppor ... 13-haltech

These sheets still have PW not including dead time as Matt was saying. To include dead time (DT) I made these tables for the id1000 and id1300 for each injector. It by no means is perfect but accounts for DT somewhat (works well around 14V not so well at 10V 8V etc.) It seems to work better than not having it.

Both of these were made from the COBB Subaru characterization table not the Haltech ones you mentioned.
Attachments
LOW PW ID1300 PER INJ COMP.JPG
LOW PW ID1000 PER INJ COMP.JPG

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HaltechMatthew
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Re: Low PW Compensation

Postby HaltechMatthew » Mon Jul 24, 2017 3:02 pm

Just an FYI, but we are adding the tables needed for this and they should hopefully appear in the next update.

Spadam9
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Re: Low PW Compensation

Postby Spadam9 » Thu Oct 12, 2017 11:22 am

had an update, no LPW tables, next one hopefully?

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HaltechMatthew
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Re: Low PW Compensation

Postby HaltechMatthew » Fri Oct 13, 2017 1:46 pm

Code is apparently done but needs reviewing before release. It might make it to the next one.


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