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.

Provided is an injector control unit capable of preventing unintended fuel injection other than an engine drive period. The injector control unit includes a cutoff mechanism for cutting off current supply to the injector from at least the ignition OFF to the next ignition ON.

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.

A fuel injection controller has terminals which can be connected to the coil of the fuel injector. A first valve-open control portion supplies the valve-opening voltage to the terminals for opening the fuel injector. The first valve-open control portion stops supplying the electric supply to the coil before the fuel injector is positioned at a full-open position. Before the fuel injector is fully closed, a small injection quantity can be obtained. A demagnetization portion forms a demagnetization circuit for demagnetizing the magnetism remaining in the coil. A normal-injection portion controls the fuel injector at full-open position.

An engine includes a fuel injector. The fuel injector includes a valve body and an electromagnetic part that moves by energizing the valve body from a valve-closed position to a valve-open position. The fuel injector injects fuel when the valve body is moved to the valve-open position. In fuel injection, an ECU feeds a pre-charge current smaller than a current for operating the valve body, to the electromagnetic part in a pre-charge period at the beginning of a start of energization, and subsequently feeds a drive current for operating the valve body, to the electromagnetic part. Further, the ECU acquires a current change parameter as a parameter correlated with a speed of a rising change in drive current, and controls the feed of the pre-charge current to the electromagnetic part of the fuel injector, based on the acquired current change parameter.

An electromagnetic actuation system includes an actuator having an electrical coil, a magnetic core, and an armature. The system further includes a controllable bi-directional drive circuit for selectively driving current through the electrical coil in either of two directions. The control module provides an actuator command to the drive circuit effective to drive current through the electrical coil in a first direction to actuate the armature and in a second direction subsequent to armature actuation to oppose residual flux within the actuator. The control module includes a residual flux feedback control module configured to adapt the actuator command to converge residual flux within the actuator to a preferred flux level.

The magnetic coil driving circuit of the magnetic contactor according to the present invention comprises a semiconductor switch configured to open or close a circuit for magnetizing or demagnetizing a magnetic coil; a pulse width modulation unit configured to output a pulse signal as a control signal for turning on or off the semiconductor switch; a control unit configured to output a control signal for changing a pulse width of the pulse signal to the pulse width modulation unit; and a temperature detection and protection unit configured to detect a temperature inside the magnetic contactor, output an output signal for turning off the semiconductor switch when the temperature exceeds an allowable temperature, and control the semiconductor switch by the pulse signal from the pulse width modulation unit when the temperature is within the allowable temperature.

A method for operating an electromagnetic actuator (10) with an actuating pin (9) is proposed which comprises the following steps: —determining a pin actuation actual dead time (t11), during which the magnetic armature (15) is substantially immobile while a magnetic coil (12) is supplied with current, wherein the actual dead time ends with the current break-in at the magnetic coil, as a result of counter induction of the magnetic armature overcoming the magnetic force threshold; —determining, before a subsequent pin actuation, the starting time of the magnetic coil current supply, wherein the starting point of the current is advanced compared with that of the target movement start of the pin out of the actuator housing (13) and the determined actual dead time.

A fuel injection control method of injecting fuel to a combustion chamber through an injector, the method may include performing, by a controller electrically-connected to the injector, a main injection configured of controlling the injector to inject the fuel in a target injection fuel amount; and performing, by the controller, a pre-energizing configured of driving the injector to inject the fuel in advance, before the performing of the main injection with a predetermined idle time interposed therebetween, wherein the performing of the pre-energizing is configured of magnetizing an injector coil of the injector by applying a current to the injector during a predetermined pre-energizing time, in which a flow rate of the fuel is prevented from being generated by the pre-energizing.

An electromagnetic valve driving device which drives a fuel injection valve having a solenoid coil, includes: a regenerative switching element disposed between a first end portion of the solenoid coil and the ground; and a control unit configured to control the regenerative switching element to be in an ON state or an OFF state, wherein the control unit includes: a voltage detection unit configured to detect a voltage of the first end portion of the solenoid coil; and an abnormality detection unit configured to detect an abnormality of the regenerative switching element on the basis of the voltage detected by the voltage detection unit.