This fuel includes: a first switching element disposed between a booster circuit boosting a battery power and one end of a solenoid; a second switching element disposed between a battery and one end of the solenoid; a third switching element disposed between the other end of the solenoid and a ground; a fourth switching element disposed between one end of the solenoid and a ground; and a control unit configured to control open/closed states of the first switching element, the second switching element, the third switching element, and the fourth switching element. The control unit is configured to open the fourth switching element during a valve closing detection period of detecting closing of a fuel injection valve and to detect the closing of the fuel injection valve on the basis of a change in voltage of the other end of the solenoid.

The invention relates to a method for determining a characteristic value of a magnetic switch valve. The magnetic switch valve can be switched from a closed switch state into an open switch state, via the movement of a rotor by means of a switching magnet applied with current against a conservative restoring force. According to the invention, during the switching of the switch valve from the open state into the closed state, the time course of the current flowing through the switching magnet and/or of the voltage at the switching magnet is measured. The characteristic value to be measured is evaluated from this time course. It was recognised that every movement of the rotor against the switching magnet induced a voltage in same. Now the voltage at the switching magnet is regulated at a constant value, for one, the voltage induced by the movement can be observed as a control deviation in the short term. For another, the induced voltage causes a current flow through the switching magnets. Based on this, the kinematics of the rotor can be deduced. Given that the switching magnet has an ohmic resistance, energy is also dissipated via the current flow. This energy is the key to determining the switching path covered by the rotor when switching between the closed and the open state. The invention also relates to a measuring device that is particularly suitable for the method.

A fluid injector comprising a coil arranged to drive a pump from a first state to a second state when energized, so as to pump a dosing fluid; a PN junction electrically arranged across the coil to discharge energy stored in the coil when the voltage across the coil is above a threshold. In one particular embodiment, the fluid injector is a selective catalytic reduction dosing fluid injector.

An injection control device of capable of correcting an energization time even in an S/N non-guaranteeable situation includes: an energization controller calculating an energization time correction amount based on an area correction performed by an energization time correction amount calculator regarding electric current flowing in a fuel injection valve when the fuel injection valve is electrically driven for injecting fuel; and an energization instruction time calculator correcting an energization instruction time for fuel injection in a next cycle and thereafter by using the energization instruction time correction amounts in or before a current cycle.

A method for controlling a fuel injector includes applying a spill valve current, applying a control valve current, the control and spill valves including components in electrical communication with each other, and detecting a timing at which the spill valve returns to an open position based on induced spill valve current. The method includes detecting a timing at which the control valve returns to a resting position based on induced control valve current, the induced spill valve current and the induced control valve current being included in respective freewheeling currents that at least partially overlap each other, adjusting a spill valve current that is applied during an injection, based on the detected spill valve return timing, and adjusting a control valve current that is applied during the injection, based on the detected control valve return timing.

An injection control device includes: a fuel injection quantity command value output unit that outputs a command value for a fuel injection quantity of a fuel injection valve; and a controller that executes current control on the fuel injection valve. The controller executes current area correction by calculating an area correction amount for an energization time to cause an integrated current value of an energization current profile and the integrated current value of a current to be equal to each other. Correction control of the current area correction is changed based on a detection signal of a cooling water temperature of an internal combustion engine.

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 system includes a fuel injector, the fuel injector having an injection control valve, a solenoid that, when energized, is configured to modify a position of the injection control valve, and a controller. The controller is configured to generate a command for energizing the solenoid, identify variability in one or more injection events, and based on the identified variability, increase an amount of energy supplied to the solenoid.

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 of capable of correcting an energization time even in an S/N non-guaranteeable situation includes: an energization controller calculating an energization time correction amount based on an area correction performed by an energization time correction amount calculator regarding electric current flowing in a fuel injection valve when the fuel injection valve is electrically driven for injecting fuel; and an energization instruction time calculator correcting an energization instruction time for fuel injection in a next cycle and thereafter by using the energization instruction time correction amounts in or before a current cycle.