Still in the long term purpose of understanding the various factors of consumption of my car, I recently discovered that I have about 15-20% difference between the liter/km (and indeed, liters) given by the car computer vs the value I obtain by filling the tank quite to the same max level each time divided by km done since the last filling.
-> Where is the problem ?
On a few measures on more than 40l, I see about 7l of difference between liters used according to the computer vs the gas pump. So I don't think imprecision of my "filling at same level" could explain. Idem for evaporation (plus it's in the wrong order, since the computer see more liters consumed than what I do have to refill).
-> On which kind of sensors is based the consumption evaluation? tank level, or some accumulated flux at injection? Or more indirect? Are some values empirically estimated rather than measured, or accumulated with bad precision? Are my sensors faulty, or is it quite a common imprecision?