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Fuel pressure sensor on 1:1 regulator - Correct way to setup Injector dead time table?


TnF

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Hello guys. I have my engine running Injector Dynamics 1050x injectors @~3bar base fuel pressure on a 1:1 fuel pressure regulator. Was running them on a 2D injector dead time table with correct short pulse adder table, and last week i've got a 10bar (absolute?) fuel pressure sensor of which i've hooked up and wired correctly. Now i am doing the map setup to change to the 3D injector dead time table and i am confused (already changed Fuel system type from MAP referenced to FP sensor, that is correct right?). The following data i have is 100% correct (fuel pressure vs voltage vs injector lag time). Now should i use differential fuel pressure instead of fuel pressure? If i do this shouldn't i have to subtract 3bar (300kpa - aka my base fuel pressure) from the x-axis values shown in my screenshot? Or does the model internally calculates this correctly the way i have it set up in the screenshot right now?

You see my "problem" is that if i use differential fuel pressure this means in case the BASE fuel pressure changes for whatever reason the system will compensate incorrectly and it will require re-adjustment of the x-axis values. The way i see this to function correctly is if the model when set up to MAP referenced, to take account the 3d table i have below automatically assuming i gave it a correct base fuel pressure.

I am pretty sure i am mistaken somewhere in my thinking because i am confused, so if you can please shed some light i would really appreciate it!

 

edit: btw i've noticed the 3d table has 2 decimal places instead 3 decimal places of the 2d table, am i losing something?

edit2: After thinking it about a lot i think i've got it, just changing the x-axis of this table in my screenshot from fuel pressure to differential fuel pressure should net me the correct results! This is because for example if i had my base fuel pressure to 300kpa, the engine idle to -50kpa MGP then the fuel pressure would be 300-50=250kpa and then the DP=250-(-50)=300kpa which can looked up on this table. This means if base fuel pressure = differential fuel pressure on 1:1 regulator meaning for any change it will be compensated by this table! Correct me if i'm wrong :)

fuelpressure.png

Edited by TnF
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