Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.