Well, I'd restate it as "I've entered 7 data points for dead time versus voltage, does the interpolation routine use all of them?", to which the answer appears to be "No, we're going to ignore one of them."Marek wrote:So you're really asking "Do I have a 'free' seventh data point on the curve at 13.2v?" to which the answer would be no.
Seems to me that was bad call.
Given that disappointment, I agree that I can rework my compensation curves to better use the six available points. And I will.
Regarding the injector data, I completely agree that the bump looks suspect. However, I saw it on multiple injectors, and the bump appeared again when I retested the "guilty" injectors. It did not appear in all the injectors (I tested six). I can't explain how it is happening, but I have not studied the dynamic behavior of solenoid valves. One WAG is some kind of resonance that occurs at a particular pintle rate.
My injector flow bench uses National Instruments Compact RIO controller hardware and an FPGA timed loop structure in the LabVIEW code. The FPGA in my Compact RIO runs at 40 MHz (it's an older model), so loop timing granularity is 25 ns. My pulse timing is very, very accurate! Orders of magnitude better than what it needs to be. I wrote the code so that the injectors fire one at a time to minimize fuel pressure fluctuations. The bench is quite repeatable, far better than it was when I bought it.
http://www.ni.com/compactrio/
Edit: Some of my stuff from a decade ago is still on the National Instruments web site.
http://sine.ni.com/cs/app/doc/p/id/cs-11023
Jeff