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.

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 drive circuit is controlled when power is interrupted. When power is turned off, a main power supply is switched to a sub-power supply, and a residual charge of a step-up circuit is lowered to a drive voltage of a drive circuit using a step-down circuit is used as the sub-power supply.

A drive circuit is controlled when power is interrupted. When power is turned off, a main power supply is switched to a sub-power supply, and a residual charge of a step-up circuit is lowered to a drive voltage of a drive circuit using a step-down circuit is used as the sub-power supply.

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 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 supply system includes an electronic control unit that outputs a target fuel pressure for controlling a low-pressure pump and an engine status, and a fuel pump controller (FPC) that generates a drive signal for driving the low-pressure pump based on the target fuel pressure. The FPC is configured to obtain an actual fuel pressure, to set a duty ratio and to perform a feedback control for the actual fuel pressure to follow the target fuel pressure, and to set a lower limit guard value based on the engine status. The lower limit guard setter sets a duty ratio of 0% as the lower limit guard value when the engine status indicates a stop of the engine.

A device comprises: an injector for injecting fuel into an engine combustion chamber, a switch formed by an injector housing and an injector nozzle needle and which changes its switching state depending on a closed or open state of the injector, an input line for supplying energy to an actuating element which adjusts the nozzle needle in its two states, an output line for conducting energy away from the actuating element, and an evaluation unit for detecting the switching state of the switch, wherein a first switch contact of the switch is connected to an electrical input line of the injector, a second switch contact of the switch is connected to ground, and the evaluation unit is configured to carry out a signal measurementon the input line and/or an output line to conclude a switch state.

A device comprises: an injector for injecting fuel into an engine combustion chamber, a switch formed by an injector housing and an injector nozzle needle and which changes its switching state depending on a closed or open state of the injector, an input line for supplying energy to an actuating element which adjusts the nozzle needle in its two states, an output line for conducting energy away from the actuating element, and an evaluation unit for detecting the switching state of the switch, wherein a first switch contact of the switch is connected to an electrical input line of the injector, a second switch contact of the switch is connected to ground, and the evaluation unit is configured to carry out a signal measurementon the input line and/or an output line to conclude a switch state.

A control device controls a drive current that flows through a drive coil of a fuel injection valve that is electromagnetically driven. A control device includes a determination unit configured to determine whether a supply fuel pressure, which is a pressure of fuel supplied to the fuel injection valve, is higher than a determination pressure at which the fuel pressure is determined abnormally high; a first control unit configured to control the drive current in a first mode when the determination unit determines that the supply fuel pressure is not higher than the determination pressure; and a second control unit configured to control the drive current in a second mode that facilitates maintaining of the fuel injection valve in an open state more than in the first mode when the determination unit determines that the supply fuel pressure is higher than the determination pressure.