Magneti Marelli S.p.a.

Marelli Europe S.p.a.

Marco Parotto

Gabriele Serra

Claudio Guido

Matteo De Cesare

Domenico Paolino

Stefano Sgatti

Fabio Sensi

Giovanni Prodi

Saverio Armeni

Tommaso Cardellini

Luigi Santamato

Romito Tricarico

Andrea Leoni

A method to estimate the temperature of an electromagnetic actuator, which entails a preliminary step in which to define a first threshold value for the current or for the voltage; and define a characteristic curve of the actuator family in the plane temperature/time needed to reach the threshold value; a step in which to carry out a reference measurement, in which, using the characteristic curve, a reference time needed by the electromagnetic actuator to reach the first threshold value is associated with a known reference temperature; and a step in which to carry out a series of measurements in which to determine the time needed by the electromagnetic actuator to reach the first threshold value, calculate the deviation between the time needed by the electromagnetic actuator to reach the first threshold value and the reference time; and determine the temperature of the electromagnetic actuator, using the characteristic curve, by associating the temperature of the electromagnetic actuator with the sum of the deviation and of the reference time.

Method to estimate the temperature of an electromagnetic actuator

The invention relates to a method to control a fuel pump for a direct injection system of a heat engine provided with a common rail comprising the steps of determining a minimum threshold based on the pressure in the common rail and on the speed of the heat engine, on the temperature of the high-pressure pump and on the inlet pressure of the high-pressure pump; calculating the objective fuel flow rate to be fed by the high-pressure pump to the common rail instant by instant in order to have the desired pressure value inside the common rail; comparing the objective fuel flow rate with the minimum threshold; and controlling the high-pressure pump based on the comparison between the objective fuel flow rate and the minimum threshold.

Method to control a high-pressure fuel pump for a direct injection system

Method to determine a closing instant of an electromagnetic fuel injector; in a beginning instant of the injection, a positive voltage is applied to a coil of an electromagnetic actuator so as to cause an electric current to circulate through the coil, said electric current determining the opening of an injection valve; in an end instant of the injection, a negative voltage is applied to the coil of the electromagnetic actuator so as to cancel the electric current circulating through the coil; a first voltage time development is detected at least one end of the coil of the electromagnetic actuator after the cancellation of the electric current circulating through the coil; the voltage actuation time development is compared with a voltage comparison time development; and the closing instant of the electromagnetic injector is determined based on the comparison between the voltage actuation time development and the voltage comparison time development.

Method to determine a closing instant of an electromagnetic fuel injector

Method to determine an opening time of an electromagnetic fuel injector; the electromagnetic fuel injector is controlled using a series of progressively increasing energization times of the electromagnetic actuator; for each control of the electromagnetic injector, the presence or the absence of a closing of the injection valve is detected; the opening time is identified, which is equal to an intermediate value between the last energization time of the electromagnetic actuator for which the absence of a closing of the injection valve was determined and the first energization time of the electromagnetic actuator for which the presence of a closing of the injection valve was determined.

Method to determine an opening time of an electromagnetic fuel injector

A method refreshes an injection law of a fuel injector to be tested in an injection system. The method comprises steps of establishing a desired fuel quantity for the fuel injector to be tested, performing at least one first measurement opening of the fuel injector to be tested in a test actuation time, determining a pressure drop in a common rail during the first measurement opening of the fuel injector to be tested, determining a first fuel quantity that is fed during the first measurement opening, calculating a second fuel quantity as a difference between the desired fuel quantity and the first fuel quantity, and performing a second completion opening of the fuel injector to be tested for feeding the second fuel quantity needed to reach the desired fuel quantity.

Method for refreshing the injection law of a fuel injector

A method determines an injection law of a fuel injector to be tested in an injection system and includes steps of: completely interrupting feeding of fuel from a fuel pump to a common rail; avoiding opening of all injectors except for one to be tested; measuring initial pressure of the fuel inside the rail before starting the opening of the injector; opening the injector for consecutive openings with a same test-actuation time; measuring final pressure after ending the opening; determining a pressure drop in the rail during the opening (equal to a difference between the initial and final pressures); estimating, according to the pressure drop, a fuel quantity that is actually injected by the injector when the injector is opened for the time; and causing an internal-combustion engine using the system to rotate by an external actuator during the openings to allow execution of consecutive openings with the same time.

Method for determining the injection law of a fuel injector using a roller-test bench

A method for determining the closing time of an electromagnetic fuel injector including the steps of applying at a starting time of the injection a positive voltage to the coil of the electromagnetic actuator in order to circulate through the coil an electric current which causes the opening of an injection valve; applying at an ending time of the injection a negative voltage to the coil in order to annul the electric current flowing through the coil; detecting the trend over time of the voltage across the coil after the annulment of the electric current flowing through the coil; identifying a perturbation of the voltage across the coil; and recognizing the closing time of the injector that coincides with the time of the perturbation of the voltage.

Method for determining the closing time of an electromagnetic fuel injector

A method determines an injection law of a fuel injector to be tested in an injection system and includes steps of: completely interrupting feeding of fuel from a fuel pump to a common rail; avoiding opening of fuel injectors except for one injector to be tested; measuring initial pressure of the fuel inside the rail before starting the opening of the injector; opening the injector for consecutive openings greater than one with a same test-actuation time; measuring final pressure of the fuel inside the rail after ending the opening of the injector; determining a pressure drop in the rail during the opening of the injector, which is equal to a difference between the initial and final pressures; and estimating, according to the pressure drop in the rail, a fuel quantity that is actually injected by the injector when the injector is opened for the test-actuation time.

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Bologna, Italy

Marco Parotto