Patent ID: 8676473

Claim:
Method for the self-learning of the variation of a nominal functioning feature of a high pressure pump in an injection assembly of an internal combustion engine; the high pressure pump feeds the fuel to a common rail connected to injectors and is controlled by a solenoid valve depending on an objective pressure inside said common rail and using the nominal functioning feature which provides a delivery of fuel pumped in the common rail according to a closing angle of the solenoid valve; the method for the self-learning comprises, when the internal combustion engine is in a cut-off condition, the steps of: determining the value of the pressure leaks due to blow-by in the common rail; measuring the real pressure of the fuel inside the common rail; actuating the high pressure pump for a given number of learning cycles controlling the solenoid valve with a closing angle corresponding in the nominal functioning feature to a predetermined learning delivery of fuel; measuring the real pressure of the fuel inside the common rail at the end of the learning cycles; estimating the expected pressure of the fuel inside the common rail at the end of the learning cycles according to the real pressure of the fuel inside the common rail before the learning cycles, according to the pressure leaks due to blow-by, according to the predetermined learning delivery of fuel and according to the stiffness of the system; determining a pressure deviation between the real pressure and the expected pressure of the fuel inside the common rail at the end of the learning cycles; and updating a correction angle of the nominal functioning feature according to the pressure deviation.