A fuel injection control device includes an injection valve drive circuit that drives a plurality of injection valves, a booster circuit that generates a boosted voltage supplied to the injection valve drive circuit; and a fuel pump drive circuit that drives a fuel pump for compressing fuel of an internal combustion engine. The fuel pump drive circuit is configured to, when driving the fuel pump, regenerate energy into the booster circuit. The injection valve drive circuit is configured to, during a non-drive period of the injection valves or during a period in which the fuel pump is intermittently driven continuously, perform a non-valve opening energization on at least one of the plurality of injection valves.

A drive device capable of detecting individual variations of an injection quantity of a fuel injection device of each cylinder and adjusting a current waveform provided to an injection pulse width and a solenoid such that the individual variations of the fuel injection devices are reduced. The fuel injection device in the present invention includes a valve body that close a fuel passage by coming into contact with a valve seat and opens the fuel passage by separating from the valve seat and a magnetic circuit constructed of a solenoid, a fixed core, a nozzle holder a housing and a needle and when a current is supplied to the solenoid a magnetic suction force acts on the needle and the needle has a function to open the valve body by colliding against the valve body after performing a free running operation and changes of acceleration of the needle due to collision of the needle against the valve body are detected by a current flowing through the solenoid.

A control method of a fuel supply pump includes moving an anchor in the closing valve direction by passing a maximum drive current through the solenoid, and thereafter holding the anchor at a closing valve position by passing a holding current for keeping a closing valve state through the solenoid. The holding current is smaller than the maximum drive current. A current value of a first drive current is smaller than a current value of the holding current. A current value of a second drive current overlaps a range of the current value of the holding current. A current value of a third driving current is equal to or more than the current value of the holding current.

A control device controls a drive current that flows through a drive coil of a fuel injection valve that is electromagnetically driven. A control device includes a determination unit configured to determine whether a supply fuel pressure, which is a pressure of fuel supplied to the fuel injection valve, is higher than a determination pressure at which the fuel pressure is determined abnormally high; a first control unit configured to control the drive current in a first mode when the determination unit determines that the supply fuel pressure is not higher than the determination pressure; and a second control unit configured to control the drive current in a second mode that facilitates maintaining of the fuel injection valve in an open state more than in the first mode when the determination unit determines that the supply fuel pressure is higher than the determination pressure.

An injection control device controls a drive of a solenoid in a high pressure pump for pressurizing fuel to an internal combustion engine. The injection control device includes a transistor on an upstream side of a power supply path from a direct current power supply line to the solenoid and a transistor provided on a downstream side of the power supply path. The injection control device further includes a diode at a position between an upstream terminal of the solenoid and ground, a transistor arranged in parallel with the diode, and a drive controller. The drive controller drives the solenoid to an open position by switching ON the transistors on the upstream and downstream sides of the power supply path.

An energization instruction switch switches energization instruction signals to instruct energization of fuel injection valves. A first cylinder designation switch designates one of the energization instruction signals to designate a valve closing detection cylinder. A valve closing detection unit monitors downstream voltage of the fuel injection valve to detect occurrence of an inflection point in change of the downstream voltage to detect a valve closing. A second cylinder designation switch designates one of the downstream voltages and designates the valve closing detection cylinder. A valve closing time measuring unit measures a valve closing time, which is from a switching timing of the energization instruction signal from ON to OFF to a valve closing detection timing, for injection of the valve closing detection cylinder. A valve closing time learning unit learns the valve closing time measured by the valve closing time measuring unit.

A fuel injection control method of injecting fuel to a combustion chamber of an engine through an injector, the method may include pre-energizing to drive the injector during a predetermined pre-energizing time; and performing, by the controller, a main injection in which the injector is controlled by the controller to inject the fuel into the combustion chamber by a target injection amount, after the pre-energizing of the injector, wherein the pre-energizing magnetizes an injector coil of the injector in advance by applying the amount of current preventing the flow rate of the fuel from being generated by the pre-energizing, to the injector during the pre-energizing time.

Various embodiments include a method for controlling a pressure dissipation valve comprising a closure element, a spring applying a spring force urging the closure element toward the closed position, and an electromagnetic actuator responding to an applied voltage to urge the closure element to an open position. The method may include: applying a constant voltage until the closure element begins motion counter to the spring force; immediately ending the voltage upon the beginning of motion; thereafter, applying a pulsed voltage to the actuator to induce a substantially constant holding-open current intensity; maintaining the pulsed voltage for a predetermined duration to hold the closure element open; and interrupting the application of voltage after the predetermined duration, wherein the closure element moves into the closed position as a result of the spring force.

A fuel injection control device is for a fuel injection system including a fuel injection valve for injecting a fuel in an internal combustion engine. The fuel injection system is configured to perform multiple-stage injection for injecting fuel multiple times in one combustion cycle. The fuel injection control device includes an information acquisition unit to acquire a parameter, which indicates an influence of a pre-stage injection on a post-stage injection, in the pre-stage injection and the post-stage injection subsequent to the pre-stage injection in the multi-stage injection. The fuel injection control device further includes a correction unit to correct a mode of the post-stage injection based on the parameter.

An increase control unit causes to apply a first voltage to a coil of a fuel injection valve to increase a driving current of the coil to a peak value. A holding control unit stops application of the first voltage, when the driving current increases to the peak value, and subsequently switches between a first holding control and a second holding control. The first holding control is to apply a second voltage lower than the first voltage to the coil based on at least one of the peak value, the second voltage, and a fuel pressure, to hold the driving current at a target current. The second holding control is to apply the first voltage to the coil to hold the driving current at the target current. The holding control unit performs one of the first holding control and the second holding control which is switched.