Disclosed is a method for controlling a DC-DC voltage converter for current-driving at least one fuel injector of a motor vehicle internal combustion engine. The method notably includes the steps of determining a time referred to as the “recovery” time at which the output voltage crosses the predefined high voltage threshold, of determining a time referred to as the “drop” time, corresponding to the start of injection, at which the output voltage decreases below the predefined high voltage threshold, and of calculating the time elapsed between the recovery time and the drop time.

Disclosed is a method for controlling a DC-DC voltage converter for driving with current at least one fuel injector of a motor-vehicle internal combustion engine. The method includes, when the transistor is switched from the off state to the on state, triggering a counter for measuring time, and, if at the end of a preset time called the “observation” time, the amplitude of the peak current has not reached its maximum value, steps of commanding that transistor so that the transistor switches from the on state to the off state, of keeping the transistor in the off state for a preset time called the “cooling time”, and of commanding the transistor so that the transistor switches to the on state at the end of the cooling time.

An electromagnetic valve drive device includes: a state detection unit configured to detect an on-state or an off-state of a first switch and a second switch forming a boosting circuit; a boosting control unit configured to control a boosting operation, by performing a synchronous rectification control on switching of the first switch and the second switch, depending on the state of the first switch or the second switch detected by the state detection unit; and a drive circuit configured to drive an electromagnetic valve by supplying a voltage boosted by the boosting operation to the electromagnetic valve.

An injection control device includes a boost controller performing boost control of a boosted voltage generated by a booster circuit until a boosted voltage, which is generated in a boost capacitor, rises to a full-charge threshold when the boosted voltage falls below a charge start threshold. When a power interruption controller interrupts electric current supplied to the fuel injection valve by the drive unit, a regeneration unit regenerates electric current generated in the fuel injection valve to the boost capacitor of the booster circuit. The boost controller stops the boost control of the booster circuit when at least the electric current is regenerated by the regeneration unit to the boost capacitor of the booster circuit after the interruption control by the power interruption controller.

An injection control device includes a boost controller performing boost control of a boosted voltage generated by a booster circuit until a boosted voltage, which is generated in a boost capacitor, rises to a full-charge threshold when the boosted voltage falls below a charge start threshold. When, for stopping a peak current by a drive unit, a power interruption controller interrupts electric current supplied to the fuel injection valve by the drive unit as interruption control (i) of an application voltage to a fuel injection valve or (ii) of a constant current by the drive unit, a regeneration unit regenerates electric current generated in the fuel injection valve to the boost capacitor of the booster circuit. The boost controller upward-shifts (i.e., raises) the full-charge threshold of the booster circuit.

An injection control device includes a boost controller performing boost control of a boosted voltage until a boosted voltage, which is generated in a boost capacitor, rises to a full-charge threshold when the boosted voltage falls below a charge start threshold. A drive unit supplies electric current to a fuel injection valve from a start timing t1 of an injection instruction period. A power interruption controller interrupts electric current supplied to the fuel injection valve by the drive unit. A regeneration unit regenerates electric current generated in the fuel injection valve which is caused by interruption control by the power interruption controller to the boost capacitor of the booster circuit.

Disclosed is a method for regulating the duty cycle of a controlled current signal of a conversion module of a voltage converter including a step of measuring, by the microcontroller, the duty cycle of the envelope of the controlled current signal, and when the value of the duty cycle is below a predetermined threshold, a step of controlling, by the microcontroller, the current control module to decrease the amplitude of the control signal and that the duty cycle of the envelope of the controlled current signal thus tends toward a predetermined threshold, or when the value of the duty cycle is higher than the predetermined threshold, a step of controlling, by the microcontroller, the current control module so the current control module increases the amplitude of the controlled current signal and that the duty cycle of the envelope of the controlled current signal thus tends toward the predetermined threshold.

An injection control device controls the opening and dosing of a fuel injection valve by performing peak current drive and constant current drive and controls injection of fuel from the fuel injection valve to an internal combustion engine. The injection control device includes a preheat current energization control unit configured to, when a temperature of a solenoid coil of the fuel injection valve prior to starting the internal combustion engine is lower than a predetermined temperature, energize the fuel injection valve with a preheat current having an output density that causes the temperature of the solenoid coil to increase, the preheat current being within a range that maintains the fuel injection valve in a valve closed state, and when the temperature of the solenoid valve increases to or above the predetermined temperature, stop the energization of the fuel injection valve with the preheat current.

Provided is a booster device for driving an injector which can suppress an insufficiency of a boost voltage applied to the injector even when the fuel injection interval is short. A boost driver (switching element) is connected to a boost coil in series and turns on/off the conduction of the boost coil. A boost capacitor applies a voltage to the injector. A boost diode has an anode connected to a connection point of the boost coil and the boost driver and a cathode connected to the boost capacitor. A boost gate control circuit controls the boost driver to be turned on/off so as to increase a charging speed of the boost capacitor increases when a decision period indicating a period corresponding to an injection interval of the injector is equal to or less than the first threshold value.

Disclosed is a method for controlling a module for driving a transistor of a DC-DC voltage converter allowing at least one fuel injector of a motor-vehicle internal combustion engine to be controlled. The method includes a step of measuring the amplitude of the current flowing through that of the first switch or of the second switch that is in the on state, a step of determining the electric charge transported by the current, and a step of interrupting the operation of the drive module when the determined electric charge is higher than a preset maximum electric-charge threshold.