Methods and systems are provided for moving an injector needle of a fuel injector assembly from a first position to a second position to provide a first fuel injection at the first position, and moving the needle from the second position to the third position to provide a second fuel injection at the third position, and moving the needle back to the first position via the second position, and providing a third fuel injection at the second position. In this way, three fuel injections may be performed during a single actuation cycle of the injector during a single combustion cycle.

A high-pressure pump includes a plunger reciprocating in conjunction with rotation of a rotational shaft to be able to change a volume of a pressurizing chamber and a control valve having a first valve body and a second valve body disposed in a fuel suction passage that communicates with the pressurizing chamber and supplies/blocks fuel to/from the pressurizing chamber by displacing the valve body in an axial direction by switching between energization and non-energization of a coil. An ECU adjusts a fuel discharge amount of the high-pressure pump by switching a valve opening and a valve closing of the control valve by the energization control of the coil. The ECU detects movement of the valve body with respect to a drive command of the valve opening or the valve closing of the control valve and executes an actuation determination of the high-pressure pump on the basis of a detection result.

A method for determining the movement behavior of a fuel injector having a coil drive includes: (a) applying an electrical excitation to a coil of the coil drive, which prompts an opening movement of a valve needle; (b) recording the temporal progression of a first electrical measurement variable of the coil; (c) determining the time when the opening movement ends based on the recorded temporal progression of the first electrical measurement variable; (d) modifying the electrical excitation of the coil such that the valve needle performs a closing movement; (e) recording the temporal progression of a second electrical measurement variable of the coil; and (f) determining the time when the closing movement ends based on the recorded temporal progression of the second electrical measurement variable. One of the two measurement variables is the voltage present at the coil and the other is the intensity of current flowing through the coil.

A fuel injection control device includes a valve closing detection unit (54) to detect a valve closing timing by using either of an electromotive force quantity detection mode and a timing detection mode, a selection unit (21) to select either of the electromotive force quantity detection mode and the timing detection mode for detecting the valve closing timing, and a correction unit (21) to calculate a correction coefficient for correcting a requested injection quantity so as to reduce the difference between an estimated injection quantity and the requested injection quantity, and the selection unit selects the electromotive force quantity detection mode regardless of the value of the requested injection quantity when the calculation of the correction coefficient is not completed.

A pressure reducing valve control apparatus is provided for a fuel supply system having a common rail and a pressure reducing valve to control rail pressure in the common rail by controlling a current supply state of the pressure reducing valve. The pressure reducing valve operates to open a valve body for discharging fuel from the common rail against a biasing force applied in a valve-closing direction by fuel-generated valve-opening force biasing the valve body in a valve-opening direction by the rail pressure and an electromagnetic force generated by current supply to an electromagnetic coil. The ECU starts to open the valve body during a period of holding a hold value by holding current supplied to the electromagnetic coil at a predetermined hold value after starting current supply to the electromagnetic coil. The ECU sets the hold value to increase as the rail pressure decreases.

A method for heating a sliding camshaft actuator at cold engine start wherein the sliding camshaft actuator includes at least one magnetic field generating coil having a core, a piston armature disposed in the core of the at least one magnetic field generating coil, a magnet in mechanical communication with the piston armature, and an actuator pin in mechanical communication with the magnet. The method includes detecting a cold engine start condition and reversing an energizing voltage on the at least one magnetic field generating coil when the outside temperature is below a predetermined temperature threshold. The reverse energizing voltage on the at least one magnetic field generating coil is maintained for a predetermined period of time to heat the piston armature, the magnet, and the actuator pin.

A fuel injection control device includes a correction unit to calculate a correction coefficient for correcting a valve closing timing detected by an electromotive force quantity detection mode by using a valve closing timing detected by a timing detection mode. An estimation unit estimates an estimated injection quantity by using a valve closing timing after corrected by using a correction coefficient when the electromotive force quantity detection mode is selected by a selection unit and a valve closing timing is detected by the electromotive force quantity detection mode.

An injection controller has a voltage applicator that applies a voltage to a driving coil of an injection valve. After a voltage is applied to the driving coil with a peak current for opening the injection valve, the voltage applicator applies a power supply voltage to the driving coil in an ON-OFF manner, to supply the driving coil with a less-than-peak current. A comparator detects whether a terminal voltage at a terminal of the coil is less than a predetermined threshold voltage. Upon detecting that the terminal voltage is less than the threshold voltage, a discharge switch applies a boosted voltage to the driving coil.

A method of controlling the operation of a solenoid activated fuel injector, actuator being operated by applying a activation pulse profile to the solenoid. The method includes measuring the voltage across, or current through, the solenoid during a time period of the valve closing phase, subsequent to a valve opening phase. The method also includes determining at least one parameter from the measuring step. The method also includes controlling and varying the activation pulse profile during a subsequent activation/fueling cycle of the fuel injector based on the parameter.

A fuel injection control device includes a valve closing detection unit to detect a valve closing timing by using either of an electromotive force quantity detection mode and an timing detection mode and a selection unit to select either of the electromotive force quantity detection mode and the timing detection mode for detecting the valve closing timing, and the selection unit: selects the timing detection mode when a requested injection quantity is larger than a prescribed reference injection quantity in partial lift injection; and selects the electromotive force quantity detection mode when the requested injection quantity is smaller than the reference injection quantity.