Patent ID: 7789068

Claim:
A control method of a direct injection system of the common rail in an internal combustion engine; the control method comprises the steps of: feeding the pressurized fuel to a common rail by means of a high-pressure pump presenting at least one pumping element mechanically operated by a drive shaft of the internal combustion engine; measuring the angular position of the drive shaft; measuring the fuel pressure (P rail ) in the common rail; analyzing the oscillations of the fuel pressure (P rail ) in the common rail; and determining phase of the pumping element of the high-pressure pump with respect to the drive shaft according to the oscillations of the fuel pressure (P rail ) in the common rail when there is no injection; wherein the step of determining the phase of the pumping element of the high-pressure pump with respect to the drive shaft comprises the further steps of: determining the angular position of the drive shaft at which the fuel pressure (P rail ) in the common rail reaches a relative maximum; and determining the angular position of the drive shaft at which the TDC of the pumping element occurs according to the angular position of the drive shaft at which the fuel pressure (P rail ) in the common rail reaches a relative maximum; and wherein the step of determining the angular position of the drive shaft in which the fuel pressure (P rail ) in the common rail reaches a relative maximum comprises the further steps of: determining a variation model of the fuel pressure (P rail ) in the common rail according to the position of the pumping element of the high pressure pump; detecting a sequence of measurements of the fuel pressure (P rail ) in the common rail during a pumping cycle by correlating the corresponding angular position of the drive shaft at the time of the measurement to each measurement; and estimating the angular position of the drive shaft at which the fuel pressure (P rail ) in the common rail reaches a relative maximum using the variation model of the fuel pressure (P rail ) combined with the measurements of the fuel pressure (P rail ).