Systems and methods for improving accuracy of an amount of fuel injected to an engine are disclosed. In one example, a maximum fuel injector holding current value is adjusted from a higher value to a lower value within a predetermined amount of time of an end of fuel injection. By adjusting the maximum fuel injector holding current value, it may be possible to reduce variation in an amount of fuel that is injected via the fuel injector.

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.

Method for controlling a fuel injector with a solenoid actuating a needle opening the injector and a spring returning the needle to the closed position. A controller, powering the solenoid, provides a first potential connected to a first transistor's drain, the source of the first transistor connected to the first diode's anode, the cathode of the first diode connected to a second diode's cathode, to a first connector of the solenoid and to the source of a second transistor. The drain of a second transistor is connected to a second potential, the second diode's anode being connected to ground, the second potential being connected to ground via a capacitance and to the cathode of a third diode, the third diode's anode being connected to a second connector of the solenoid and to the drain of a third transistor, the source of the third transistor being connected to ground.

Provided is a solenoid valve drive device capable of accurately controlling a hysteresis value of a drive current for driving a solenoid valve. The solenoid valve drive device according to the present invention controls a set value of a hysteresis or a time width of the hysteresis based on a difference between an extreme value of the hysteresis in a peak hold period of a drive current and a set value of the extreme value.

A fuel system for an internal combustion engine includes a fuel injector, and a fueling control unit electrically connected to a solenoid in the fuel injector. The fueling control unit energizes the solenoid with a lift current pulse to lift an armature, then energizes the solenoid with a separate capture current pulse to capture the armature at a lifted position. The solenoid is deenergized a dwell time while the armature is in flight toward the lifted position. Armature lifting speed is retarded based on the deenergizing of the solenoid so as to limit bouncing of a valve pin in the fuel injector against a stop. The techniques assist in linearizing a fuel delivery curve.

An injection control device includes: a booster circuit that boosts a battery voltage; a boosting control unit that performs boosting control on the booster circuit; a charge control setting unit that sets a charge prohibition time of the booster circuit for the boosting control unit; and a maximum time specification unit that specifies a maximum valve-closing detection time based on a valve-closing detection time.

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.

An electromagnetic valve driving device that drives an electromagnetic valve for injecting a fuel, includes: a first charging route that charges a bootstrap capacitor from a battery without intervention of a boost circuit; a second charging route that charges the bootstrap capacitor from the boost circuit; and a switching control unit that switches a charging route for charging the bootstrap capacitor to the first charging route or the second charging route.

An energization control unit is configured to perform a constant current control by repeatedly switching between an on-state and an off-state of at least one upstream switch provided in an energization path of a coil of a fuel injection valve to control opening of the fuel injection valve in a drive period in which the coil is energized to drive the fuel injection valve. A current detection unit is configured to detect a coil current flowing through the coil. A valve-opening detection unit is configured to detect valve-opening timing of the fuel injection valve based on a change in at least one frequency spectrum of the coil current in a constant current control period in which the constant current control is performed. A valve-opening correction unit is configured to correct valve opening of the fuel injection valve based on a detection result of the valve-opening detection unit.

A method for identifying a type of a fuel injector installed in an internal combustion engine includes generating a control signal to supply electrical energy from a power source for actuating the fuel injector, monitoring the electrical energy, identifying a pattern in the electrical energy, the pattern being indicative of the type of the fuel injector, and outputting a notification indicative of an incorrect injector type based on the pattern.