by Alex.T » Tue Feb 12, 2013 11:30 pm
What I do is convert Injection Duration from microseconds to degrees, then add that to SOI.
Resulting EOI map will have degrees ATDC.
I start from SOI and i suppose I'm at 1250rpm and I want to inject 70mm3.
SOI map will tell me I have to start injecting at 3,6° BTDC.
Now I need to know injection duration, but in order to get that, I first have to know rail pressure.
So I open Rail Pressure map and look for IQ=70mm3 and RPM=1250. This will give me 700bar.
Now I can open Injection Duration and look for IQ=70mm3 and Pressure=700bar.
Duration for that will be 1668 µs.
All I have to do now is to convert that to crankshaft degrees.
But to go from time to angles, we need to know how much time a revolution will take at given rpm.
In this case we have 1250rpm. That means every 60 seconds 1250 revolutions.
Calculate (60/1250)=0,048
That means a revolution will take 0,048 seconds.
In microseconds will be 48000.
Now, if 48000µs is the time equivalent of 360° of rotation
1168µs would be 8,76°
Add this to SOI and you'll find EOI is 5,16° ATDC.
I prefer to use BTDC for SOI and ATDC for EOI...