Small pulsewidths calibration

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vw_chuck
Master MS/Extra'er
Posts: 633
Joined: Wed Dec 11, 2013 1:16 pm

Small pulsewidths calibration

Post by vw_chuck »

Has anyone calibrated their small pulsewidths cals? I flowed my injector from the dead time up to 2 ms in .1 ms steps and have the curve which makes a big S in some areas. Now how is my curve which is cc/pulse on the y axis and milliseconds on the x axis used to fill in my small pulsewidths tables which have milliseconds on the x and Y axis.
Should the small pulsewidths table be cc/pulse on the y axis????
Thanks for any help on this.
elutionsdesign
Super MS/Extra'er
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Joined: Mon Sep 05, 2011 1:20 pm

Re: Small pulsewidths calibration

Post by elutionsdesign »

It is set up so that the x-axis is what is actually flowing, the y-axis is what you have to set your injector pulse width TO in order for it to flow the x-axis amount. Example, 750 cc/min injector or 750 ml/min is 12.5 ml/second. If the world was perfect then setting the pulse width to 1.0 mS would give 12.5 ml/sec*.001 S or 0.0125 ml fuel. But you being smart do a calibration and find that you actually get 0.0125 ml fuel when the injector pulse width is set to 1.2 mS, so for that data point x is 1.0 and y is 1.2, both in mS. Obviously you can't accurately measure 0.0125 ml, everything is averaged over many injections, but you already knew that.
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vw_chuck
Master MS/Extra'er
Posts: 633
Joined: Wed Dec 11, 2013 1:16 pm

Re: Small pulsewidths calibration

Post by vw_chuck »

I understand the theory above and I have been trying to figure out just how to calibrate this from a graph that is milliseconds on the x axis and cc/pulse on the y axis for the better part of the afternoon to no avail. As far as I can tell this feature is uncalibratable. How would you ACTUALLY go about calibrating this, not just theory?
Thanks
Yves
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Joined: Tue Jun 17, 2014 1:23 pm
Location: Belgium

Re: Small pulsewidths calibration

Post by Yves »

I'm going through the same issue here. I can calculate the fuel flow per pulse but where do I go from there ? Figure out at what pulsewidth it flows the same as theoretically ? ?
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