Provided are an electromagnetic valve control unit and a fuel injection control device using the same that can precisely detect a change of an operating state of an electromagnetic valve, that is, a valve opening time or a valve closing time of the electromagnetic valve, precisely correct a drive voltage or a drive current applied to the electromagnetic valve, and appropriately control opening/closing of the electromagnetic valve, with a simple configuration. In an electromagnetic valve control unit for controlling opening/closing of an electromagnetic valve by a drive voltage and a drive current to be applied, the drive voltage and the drive current applied to the electromagnetic valve are corrected on the basis of a detection time of an inflection point from time series data of the drive voltage and the drive current when the electromagnetic valve is opened/closed.

The objective of the present invention is to correct deviation in the injection amount and changes in the injection timing when the voltage of a high-voltage source for a drive device decreases. This drive device for a fuel injection device is equipped with a function whereby, when the pulse width of the injection pulse is set to an energization time 815 that closes a valve after a drive current has been switched to a maintenance current, the injection pulse width when the voltage of a high-voltage source has decreased is corrected so as to be longer than the injection pulse width when the voltage of the high-voltage source has not decreased, and, when the pulse width of the injection pulse is set to an energization time 804 that closes the valve before the drive current has been switched to the maintenance current, the absolute value of the amount of correction of the injection pulse width is made smaller than when the injection pulse width is set to the energization time 815 that closes the valve after the drive current has been switched to the maintenance current.

The disclosure proposes a method for controlling discharge of a solenoid valve arranged in a vehicle, wherein the solenoid valve comprises an inductor and a plunger arranged to be moved by the inductor from a hold position to a rest position, whereby the solenoid valve is opened or closed. The method comprises stepwise discharging the inductor by discharging the inductor at a slow decay rate during an operating time period during which a final part of a movement of the plunger from the hold position to the rest position takes place. The method further comprises discharging the inductor at a fast decay rate during at least one other time period, wherein the plunger is stagnant during at least a part of said other time period, wherein the fast decay rate is faster than the slow decay rate.

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 recognized 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.

In voltage boosting circuit for performing rapid power supply to a plurality of electromagnetic coils that drive fuel-injection electromagnetic valves, an overcurrent from vehicle battery is suppressed, and continuous noise is prevented from being produced. Each of rapid-power-supply voltage boosting capacitors that are connected in parallel with each other is charged from corresponding one of a pair of induction devices, which are asynchronously on/off-magnetized by first and second voltage boosting control circuits, by way of corresponding one of charging diodes in a pair; when addition value of exciting currents for induction devices in a pair continuously exceeds predetermined value, driving modes of one of and the other one of voltage boosting control circuits are set to large-current low-frequency mode and to small-current high-frequency mode, respectively, so that on/off timing of exciting current becomes irregular even when respective inductances values of induction devices in a pair are close to each other.

A fuel injection control device has a valve opening control portion which opens a control valve by electrically charging a piezoelectric element, and a valve closing portion which closes the control valve. The valve opening control portion includes a first rising control portion, a pause control portion and a second control portion. The first rising control portion increases a charge amount of the piezoelectric element during a first rising period. The pause control portion pauses an increase in the charge amount of the piezoelectric element during a pause period after the first rising period. The second rising control portion increases the charging amount of the piezoelectric elements again during a second rising period after the pause period. The pause period includes a period of immediately before the control valve is opened.

A control device of a fuel injection device improves stabilization in an opening operation of a valve element and stabilizes an injection amount. The control device includes a valve element to open a fuel passage by being separated from a valve seat, a movable iron core to perform an opening/closing operation of the valve element, and a fixed iron core to attract the movable iron core when a current flows to a coil. The control device includes a control unit which performs an intermediate energization in which the coil is energized again to attract the movable iron core to the fixed iron core and then the energizing to the coil is blocked and the movable iron core is displaced in a direction away from the fixed core. The control unit controls whether the intermediate energization is performed according to an injection interval of the fuel injection device.

A method for controlling a piezoelectric actuator of a fuel injector of an internal combustion engine of a vehicle, the actuator acting on valve elements to open or close the injector, respectively enabling or stopping the injection of fuel into a combustion chamber of the engine, includes the steps of: applying to the actuator a first nominal electric charge required to open the injector in accordance with the torque requested and the engine speed, to open the valve elements for fuel injection, instructing the closure of the injector to stop the fuel injection, by applying an electric discharge to the actuator to close the valve elements, the method applied from an on-board engine control unit during operation, and including applying to the actuator between these 2 steps at least one second electric charge to polarize the actuator during an opening phase of the injector and during fuel injection.

The objective of the present invention is to correct deviation in the injection amount and changes in the injection timing when the voltage of a high-voltage source for a drive device decreases. This drive device for a fuel injection device is equipped with a function whereby, when the pulse width of the injection pulse is set to an energization time 815 that closes a valve after a drive current has been switched to a maintenance current, the injection pulse width when the voltage of a high-voltage source has decreased is corrected so as to be longer than the injection pulse width when the voltage of the high-voltage source has not decreased, and, when the pulse width of the injection pulse is set to an energization time 804 that closes the valve before the drive current has been switched to the maintenance current, the absolute value of the amount of correction of the injection pulse width is made smaller than when the injection pulse width is set to the energization time 815 that closes the valve after the drive current has been switched to the maintenance current.

Methods and systems are provided for increasing a lift pump voltage to a high threshold voltage responsive to a DI pump efficiency being below a threshold efficiency, and increasing a lift pump voltage to a first threshold voltage less than the high threshold voltage responsive to a main jet pump fuel reservoir level being less than a first threshold reservoir level. The approach increases fuel jet pump performance and thereby reducing engine stalls induced by fuel vaporization, while maintaining DI pump efficiency and fuel economy.