A fuel injection control device for an internal combustion engine which is applied to a fuel injection system of the internal combustion engine, the fuel injection system including fuel injectors, driving circuits that drive the fuel injectors in each of driving systems into which the fuel injectors are divided, and current detection circuits that are provided to the driving systems, respectively, and the current detection circuits that sense driving currents of corresponding fuel injectors. The fuel injection control device includes an acquisition unit to acquire a current change parameter that is a parameter correlative to a change quantity of a sensed current per unit time in each of the driving systems, and a current correction unit to execute a current correction in at least one of the driving systems based on the current change parameter in each of the driving systems.

Appropriate detection of an abnormality of voltage information, which is a basis for correcting a fuel injection amount, becomes possible. For this reason, a fuel injection control device 127, which has a drive IC 208 controlling a fuel injection drive unit 207a to supply a high voltage to a solenoid 405 so as to open a fuel injection valve 105 and controlling the fuel injection drive unit 207a to supply a low voltage to the solenoid 405 so as to hold a valve-open state of the fuel injection valve 105, includes: a drive voltage input unit 211 that measures and outputs voltage information based on an upstream voltage of the solenoid 405 of the fuel injection valve 105 and a downstream voltage of the solenoid 405; a fuel injection amount correction unit 213 that corrects a fuel injection amount of the fuel injection valve 105 based on the voltage information output from the drive voltage input unit 211; and a voltage input function abnormality detection unit 212 that detects whether an output of the drive voltage input unit 211 is abnormal based on the voltage information output from the drive voltage input unit 211.

Disclosed is a method for triggering the switching of a switching transistor of a quasi-resonant DC-to-DC voltage converter to the on state. The method includes the steps of phase-shifting the drain voltage of the transistor by a predetermined temporal phase-shift value that corresponds to the difference between the duration of a quarter of the period of the damped sinusoidal oscillation generated when the transistor is switched off and the period of time that elapses between the command to switch the transistor to the on state and the transistor actually conducting, and, when the phase-shifted voltage is equal to the reference voltage, triggering the command to switch the transistor to the on state such that the transistor starts conducting at the time when the value of the drain voltage is at a minimum.

Disclosed is a method for reducing the electromagnetic interference produced during the switching to the on state of a transistor for switching a quasi-resonant DC-DC voltage converter. The method includes the steps of: the transistor being initially controlled so as to be in the on state on the basis of a first control current, controlling the driving module by way of the control module so that the driving module switches the transistor to the off state at a first instant; and triggering the timer from the first instant, and, if the timer reaches a predefined duration threshold, controlling, by means of the driving module, the transistor so as to be in the on state on the basis of a second control current the intensity of which is lower than the intensity of the first control current.

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.

Provided is a fuel injection control device capable of reducing variations in injection amounts of a plurality of fuel injection valves. Thus, the fuel injection control device of the present invention includes a control unit that controls voltages applied to coils of a plurality of fuel injection valves, the coils being adapted for energization. The control unit performs control such that the voltage being applied to the coil is cut off. The control unit changes a timing at which the cutoff of the voltage to the coil of at least one fuel injection valve is started or a timing at which the cutoff of the voltage to the coil of at least one fuel injection valve is ended, based on a valve closing time until closing of the fuel injection valve is completed or a valve opening time until opening of the fuel injection valve is completed.

Systems and methods for improving accuracy of an amount of fuel injected to an engine are disclosed. In one example, holding current of a fuel injector is adjusted to follow a fixed period and timing of a fuel injector off command is adjusted according to attributes of fuel injector holding current so that a fuel injector may provide a requested fuel amount. The fuel injector off command may be adjusted according to an amount of holding current that is expected to be flowing through the fuel injector at a time when the fuel injector is commanded off.

A fuel injection control device is applied to an internal combustion engine including a fuel injection valve and causes a valve body to be in a valve open state accompanying an energization of the fuel injection valve to inject fuel. The fuel injection control device acquires a dynamic parameter. The fuel injection control device acquires an injection amount parameter. The fuel injection control device calculates, based on the dynamic parameter, a dynamic correction value. The fuel injection control device calculates, based on the injection amount parameter, an injection amount correction value. The fuel injection control device corrects a fuel injection using the dynamic correction value and the injection amount correction value.

A fuel system includes a fuel injector, and a fueling control unit electrically connected to a solenoid actuator in the fuel injector. The fueling control unit is structured to energize and deenergize the solenoid actuator to lift and return an armature coupled with an injection control valve. The fueling control unit also reenergizes the solenoid actuator with an armature retarding current while the armature is in flight to stabilize closing of the injection control valve. The armature retarding current can be used to electronically trim the fuel injector to limit an error in a quantity of injected fuel.

An injection control device controls fuel injection to an internal-combustion engine by driving a fuel injection valve with an electric current to open and close the valve. The injection control device includes a boost circuit boosting a battery voltage; a boost controller controlling the boosting of the boost circuit; and a charge control setter setting charge permission or charge prohibition of the boost circuit to the boost controller. The charge control setter sets the charge permission or charge prohibition of the boost circuit to the boost controller according to a magnitude of an influence of a drive current error.