based on engine speed,accelerator pedal (for the first two mentioned, ask yourself why after a certain number of engine revolutions can no longer calculate the correction) pressure pipe,injection time(msec indicates and calculates how much time is remaining in the injector open during the phases of injections per cylinder) from here understands that the time of opening more pressure flute(on the basis of the pressure indicates how much diesel ec in the flute and so far as I inject in the early stages of injection indicated in msec etc.
I will not dwell otherwise ce to write so much
ps the explanation and a little home-made, but much more' technical