The subject matter of this specification can be embodied in, among other things, a method for characterizing a fluid injector that includes receiving a collection of waveform data, identifying a pull locus, determining a detection threshold level value, identifying a first subset of the collection of data representative of a selected first electrical waveform of the collection of electrical waveforms, identifying an opening value, identifying a representative closing value, identifying an anchor value, identifying a second subset of the collection of data based on the collection of data, the pull locus, the first subset, and the opening value, identifying a maximum electrical value, identifying an opening locus based the collection of data, the anchor value, and the maximum electrical value, identifying a hold value, and providing characteristics associated with the fluid injector comprising the pull locus, the opening locus, the hold value, the anchor value, and the representative closing value.

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.

It is an object of the present invention to provide a control method of a high-pressure fuel supply pump and a high-pressure fuel supply pump using the same capable of effectively reducing noise generated when an electromagnetic suction valve is opened. This can be realized such that, in a control method of a high-pressure fuel supply pump including a suction valve disposed on the suction side of the pressurizing chamber, a rod for urging the suction valve toward the opening valve direction, and an anchor for moving the rod in the closing valve direction with attraction by magnetic attraction caused by a solenoid being energized, when the anchor moves in the opening valve direction, a first drive current is passed through the solenoid for a predetermined period of time, and thereafter a second drive current larger than the first drive current is passed through the solenoid for a predetermined period of time.

In a drive unit of a fuel injection device, an electric current is supplied to the fuel injection device by applying a high voltage to the fuel injection device from a high voltage source whose voltage is boosted to a voltage higher than a battery voltage at the time of opening a valve of the fuel injection device. Thereafter, the electric current supplied to the fuel injection device is lowered to a current value at which a valve element cannot be held in a valve open state by stopping the applying of the high voltage from the high voltage source. Thereafter, in a stage where a supply current is switched to a hold current, another high voltage is applied to the fuel injection device from the high voltage source.

An object is to suppress an inclination of a waveform indicating an injection quantity with respect to an injection pulse particularly when a lift amount of a valve body is small and an injection pulse width is short, thereby improving control accuracy of the injection quantity of a fuel injection device. Thus, a control device for controlling a fuel injection device, which includes a valve body, a solenoid, and a movable element to open the valve body, is provided with a control unit that controls a drive voltage or a drive current to be applied to the solenoid, in which the control unit controls the drive current such that the drive current to be supplied to the solenoid decreases from a maximum drive current after the maximum drive current is supplied to the solenoid and before the valve body starts to open.

Provided is a high-pressure fuel pump in which responsiveness of closing a suction valve can be maintained even when the high-pressure fuel pump is increased in pressure or capacity of the high-pressure fuel pump is increased, thereby ensuring discharge efficiency. Therefore, the high-pressure fuel pump includes the rod that urges the suction valve in the valve opening direction, the mover that drives the rod in the valve closing direction, and the solenoid that generates a magnetic attraction force for moving the mover in the valve closing direction. After the suction valve starts moving from the suction valve closing position in the valve opening direction, the rod reaches the suction valve closing position and further moves in the valve opening direction.

An apparatus and a method for controlling a flow control valve for a high-pressure fuel pump include: a pressure sensor for fuel in a delivery pipe; a control unit for controlling an operation of a flow control valve by controlling a current applied to a coil; a power switching unit for supplying or blocking driving power supplied to the flow control valve based on a control signal of the control unit; and a current adjustment unit electrically connected/disconnected with the flow control valve by the power switching unit to reduce a current supplied to the flow control valve when the current adjustment unit is connected with the flow control valve. Therefore, a noise and a vibration by collision between the plunger and the core upon closing the flow control valve may be attenuated by adjusting a current amount applied to the 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.

In a drive unit of a fuel injection device, an electric current is supplied to the fuel injection device by applying a high voltage to the fuel injection device from a high voltage source whose voltage is boosted to a voltage higher than a battery voltage at the time of opening a valve of the fuel injection device. Thereafter, the electric current supplied to the fuel injection device is lowered to a current value at which a valve element cannot be held in a valve open state by stopping the applying of the high voltage from the high voltage source. Thereafter, in a stage where a supply current is switched to a hold current, another high voltage is applied to the fuel injection device from the high voltage source.

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.