JP2007315179A - Control method of fuel injector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method of a fuel injector capable of properly performing opening-closing operation of a fuel injection valve. <P>SOLUTION: This control method of the fuel injector controls the fuel injection valve using a solenoid and a magnetostrictive element as driving force of a valve train, and controls opening-closing of the fuel injection valve, by making an electric current flow to a magnetostrictive coil of the magnetostrictive element, by using any of a plurality of magnetostrictive element driving power sources (for example, a first boosting power source 32, a second boosting power source 33 and a 12 V power source 34) for driving the magnetostrictive element, when the electric current flows to a solenoid coil, by making the electric current flow to the solenoid coil for driving the solenoid 18. In valve opening operation and valve closing operation of the fuel injection valve, since the plurality of magnetostrictive element driving power sources can be used, the opening-closing operation of the fuel injection valve of the fuel injector can be properly performed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control method for a fuel injection device capable of appropriately opening and closing a fuel injection valve using a solenoid and a magnetostrictive element.

  An electromagnet fuel injection device used for an internal combustion engine includes an injector provided with a fuel injection valve driven by an electromagnet, a driving power source, and a fuel injection command as an operation signal provided between the power source and the injector. And a drive circuit for supplying a drive current from the power source to the injector. A battery is generally used as the driving power source.

In the injector of the electromagnet type fuel injection device, when fuel is not injected, the needle valve is pressed against the injection hole by a coil spring, and the fuel is injected by sucking the needle valve using an electromagnet during fuel injection and opening the injection hole. . However, the electromagnetic fuel injection device has a problem that the actual opening and closing operation of the fuel injection valve reacts slowly with respect to the operation signal. For this reason, in the fuel injection device of Patent Document 1, a piezoelectric, electrostrictive, or magnetostrictive element is attached to a part of the needle of the injector, and the opening and closing of the fuel injection valve is adjusted by the extension operation of the element. Has been.
Japanese Patent Laying-Open No. 2004-316644 (paragraphs 0005 to 0026, FIG. 2)

  However, in the description of Patent Document 1, the piezoelectric element is energized via an electrical terminal (not shown), and the piezoelectric element expands and contracts depending on the energization. Further, it is only described that the urging of the piezoelectric element is performed regardless of the urging of the electromagnetic operation device, and any electrical control circuit and control method can be used to open and close the fuel injection valve. It is not disclosed whether the operation is properly realized. In addition, the relationship between the operation of the piezoelectric element during the opening / closing operation of the fuel injection valve and the electromagnetic operation has not been clear.

  The present invention is an invention for solving the above-described problems, and an object thereof is to provide a control method for a fuel injection device capable of appropriately opening and closing a fuel injection valve using a solenoid and a magnetostrictive element.

  A control method for a fuel injection device according to the present invention is a control method for a fuel injection device that controls a fuel injection valve that uses a solenoid and a magnetostrictive element as driving force for a valve operating mechanism, and includes a solenoid coil for driving the solenoid. Of the magnetostrictive element using any one of a plurality of magnetostrictive element driving power sources (for example, the first boosting power source 32, the second boosting power source 33, and the 12V power source 34) for driving the magnetostrictive element. The opening and closing of the fuel injection valve is controlled by energizing the working coil.

  It is preferable that the displacement amount of the solenoid and the displacement amount of the magnetostrictive element are substantially equal.

  It is preferable that the fuel injection valve includes a first step of supplying a current to both the solenoid coil and the magnetostrictive coil to hold the fuel injection valve in the first state when the fuel injection valve is in the closed state.

  In the first state, it is preferable to include a step of opening the fuel injection valve by cutting off a current flowing through the magnetostrictive coil.

  It is preferable to further include a valve closing step of closing the fuel injection valve by supplying a current to the magnetostrictive coil in the valve open state.

  As a plurality of magnetostrictive element driving power sources, a first power source (for example, the first boosted power source 32) that outputs a first voltage boosted from a predetermined voltage, and a first voltage that is higher than the first voltage boosted from the predetermined voltage. It is preferable to use one of the second power supplies (for example, the second boost power supply 33) that outputs the second voltage.

  Preferably, the first step includes a step of passing a current through the solenoid coil and a current through the magnetostrictive coil using the first power source.

  It is preferable that the valve closing step includes a step of closing the fuel injection valve by applying a current to the magnetostrictive coil using the second power source.

  According to the present invention, a plurality of magnetostrictive element driving power sources are provided, and the magnetostrictive element driving power source can be used independently during the opening and closing operations of the fuel injection valve. Can work properly.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First embodiment.
The fuel injection device according to the present invention includes an injector 200 and a fuel injection valve control unit 100 (see FIG. 2).

  FIG. 1 is a configuration diagram conceptually showing an injector of a fuel injection device according to a first embodiment of the present invention. The injector 200 includes a solenoid 18 (an armature 14 that is a conductive solid, a fixing core 13 that is attracted to the armature 14 by an attractive electromagnetic force, a return spring 12 that biases the fixing core 13 and the armature 14, and a fixing It is composed of a holding coil 11 for applying an attractive electromagnetic force to the core 13), a cylindrical valve 22 formed of a magnetostrictive element, a magnetostrictive coil 21 for the valve 22, and a lower part of the valve 22. It comprises a valve needle 15, a seat 16, and an injection hole 17 provided in the seat. The fuel injection path, the injector outer container, and the like are not shown. Further, the valve 22 may have a shape other than a columnar shape, for example, a hollow shape.

  The solenoid 18 is a device that converts electrical energy into a mechanical linear motion. By energizing the holding coil 11, the armature 14 is electromagnetically attracted, and when the energization is stopped, the armature 14 is restored. .

  An armature 14 is joined to one end of the valve 22 and a valve needle 15 is joined to the other end. It can be moved up and down along the central axis of the drawing. The magnetostrictive element of the valve 22 is an external magnetic field generated by the magnetostrictive coil 21, and its length expands and contracts along the central axis of the drawing due to the Joule effect.

  When the injector 200 is in a closed state, the tip of the valve needle 15 opposite to the valve 22 is in pressure contact with the injection hole 17 of the seat 16. When the injector 200 is in the valve open state, the tip of the valve needle 15 opposite to the valve 22 is separated from the seat 16 and fuel is injected from the injection hole 17.

  The holding coil 11 and the magnetostrictive coil 21 are connected to the solenoid drive circuit 10 and the magnetostrictive element drive circuit 20 (see FIG. 2), respectively, and a voltage can be applied from the drive power supply 30 (see FIG. 2).

  FIG. 2 is a block diagram showing a fuel injection valve control unit of the fuel injection device according to the first embodiment of the present invention. The fuel injection valve control unit 100 shows a case of four cylinders, and includes a drive circuit FD1, a drive circuit FD2, a drive circuit FD3, a drive circuit FD4, a drive power supply 30, and a control unit 40. The holding coil 11 and the magnetostrictive coil 21 are provided in the injector 200 and are shown for explanation.

  The drive circuit FD1 includes a solenoid drive circuit 10 and a magnetostrictive element drive circuit 20, and the drive circuit FD2, the drive circuit FD3, and the drive circuit FD4 have the same configuration as the drive circuit FD1. The solenoid drive circuit 10 applies a voltage to the holding coil 11 by a command signal from the control unit 40. The magnetostrictive element driving circuit 20 applies a voltage to the magnetostrictive coil 21 by a command signal from the control unit 40.

  The drive power supply 30 includes a solenoid power supply 31, a battery power supply, or a first boosted power supply 32 that outputs a first voltage for a magnetostrictive element boosted from a predetermined voltage output from the magnet generator, a battery power supply, or a magnet generator. Are provided with a second boosted power source 33 that outputs a second voltage for the magnetostrictive element boosted from a predetermined voltage of the output of 12 and a 12V power source 34 that is a battery power source. For example, the first boost power source 32 is a 40V power source, and the second boost power source 33 is a 150V power source.

  The control unit 40 controls the opening / closing command of the drive circuits FD1 to FD4 for controlling the driving power source 30 and opening / closing the fuel injection valve. Specifically, the control unit 40 is realized by a microprocessor (not shown) or a program stored in a nonvolatile raw memory (not shown).

  FIG. 3 is a circuit diagram showing a solenoid drive circuit. The solenoid drive circuit 10 is a switch circuit that controls energization to the holding coil 11 of the injector 200. As shown in FIG. 3, the switch SW11, the switch SW12, and the switch SW13 are switching elements, and are composed of, for example, FETs.

  Note that the switch SW11, the switch SW12, and the switch SW13 may have any switching function. For example, a bipolar transistor, an IGBT (Insulated Gate Bipolar Transistor), or the like may be used.

  The drain of the switch SW13 is connected to the solenoid power supply 31, and the source of the switch SW13 is connected to one end of the holding coil 11. The gate of the switch SW13 is connected to the high voltage HI driver terminal 41 via a protective resistor R14.

  The drain of the switch SW12 is connected to the 12V power source 34, and the source of the switch SW12 is connected to one end of the holding coil 11 via the diode D11. The gate of the switch SW12 is connected to the low voltage HI driver terminal 42 through a protective resistor R13.

  The drain of the switch SW11 is connected to the other end of the holding coil 11, and the source of the switch SW11 is grounded via the resistor R11. A zener diode ZD11 is connected between the drain and gate of the switch SW11. The gate of the switch SW11 is connected to the LO driver terminal 43 via a protective resistor R12. One end of the holding coil 11 is connected to the cathode of a diode D12 that functions as a commutation diode.

  The high voltage HI driver terminal 41, the low voltage HI driver terminal 42, and the LO driver terminal 43 are connected to the control unit 40.

  To energize the holding coil 11, an ON command signal is given from the control unit 40 to the high voltage HI driver terminal 41 or the low voltage HI driver terminal 42 and the LO driver terminal 43.

  FIG. 4 is a circuit diagram showing a magnetostrictive element driving circuit. The magnetostrictive element drive circuit 20 is a switch circuit that controls energization of the magnetostrictive coil 21 of the injector 200. As shown in FIG. 4, the switch SW21, the switch SW22, the switch SW23, and the switch SW24 are switching elements, and are composed of, for example, FETs.

  Note that the switch SW21, the switch SW22, the switch SW23, and the switch SW24 may have any switching function. For example, a bipolar transistor, an IGBT, or the like may be used.

  The drain of the switch SW24 is connected to the first boost power supply 32, and the source of the switch SW24 is connected to one end of the magnetostrictive coil 21 via the diode D24. The gate of the switch SW24 is connected to the boost open driver terminal 44 via a protective resistor R25.

  The drain of the switch SW23 is connected to the second boost power supply 33, and the source of the switch SW23 is connected to one end of the magnetostrictive coil 21 via the diode D23. The gate of the switch SW23 is connected to the boosting closed driver terminal 45 through a protective resistor R24.

  The drain of the switch SW22 is connected to the 12V power supply 34, and the source of the switch SW22 is connected to one end of the magnetostrictive coil 21 via the diode D22. The gate of the switch SW22 is connected to the 12V system driver terminal 46 via a protective resistor R23. Note that a cathode of a diode D25 functioning as a commutation diode is connected to one end of the magnetostrictive coil 21.

  The drain of the switch SW21 is connected to the other end of the magnetostrictive coil 21, and is connected to the first boosting power source 32 or the second boosting power source 33 via the diode D21. The source of the switch SW21 is grounded via the resistor R21. The gate of the switch SW21 is connected to the low-side driver terminal 47 through a protective resistor R22.

  The boost open driver terminal 44, the boost close driver terminal 45, the 12V system driver terminal 46, and the low side driver terminal 47 are connected to the control unit 40.

  In order to energize the magnetostrictive coil 21, an ON command signal is sent from the control unit 40 to any one of the boost open driver terminal 44, the boost close driver terminal 45, and the 12V system driver terminal 46 and the low side driver terminal 47. Given.

Next, the operation will be described.
FIG. 5 is an explanatory diagram showing the operation principle of the fuel injection device according to the first embodiment of the present invention. As shown in FIG. 5A, the basic valve opening / closing operation of the injector 200 includes an off mode, a valve opening mode, a fuel injection mode, a valve closing mode, and a return mode. The “mode” is used to indicate the state of the valve opening / closing operation. FIG. 5B shows the voltage / current waveform of the holding coil 11, the voltage / current waveform of the magnetostrictive coil 21, the solenoid lift amount, the magnetostrictive element displacement amount, and the overall lift amount of the valve 22 in each mode. ing. The horizontal axis represents time t. The magnetostrictive element displacement amount is the amount of expansion of the magnetostrictive element according to the magnetic field applied to the magnetostrictive element, and is zero when there is no applied magnetic field, and increases (extends) as the applied magnetic field becomes stronger.

In the off mode (t <t ₁ ), the holding coil 11 and the magnetostrictive coil 21 are not energized and are closed.

In the valve opening mode, a voltage is applied to the holding coil 11 and the magnetostrictive coil 21 to prepare for valve opening. At time t ₁ , a voltage is applied to the holding coil 11. Then, an energizing current flows through the holding coil 11. As the energization current increases, the solenoid starts to lift. In time t _2, the voltage is applied to the magnetostrictive coil 21. Then, energization of the magnetostrictive coil 21 is started and an energization current flows. The current rises linearly with the inductance of the magnetostrictive coil 21 as a gradient, but gradually rises because the magnetic permeability is non-linear. As the energization current increases, the magnetostrictive element expands and the amount of displacement increases. At time t ₃ , the solenoid armature 14 is attracted and held by the holding coil 11, and the magnetostrictive element is expanded by the magnetic field generated by the energizing current and the displacement amount is increased. Since the lift amount of the solenoid and the displacement amount of the magnetostrictive element are offset, the lift amount of the entire valve is zero and the valve is closed. In FIG. 5, the start of the applied voltage of the holding coil 11 is shown before the start of the applied voltage of the magnetostrictive coil 21, but after the applied voltage to the magnetostrictive coil 21 is started. The voltage applied to the holding coil 11 may be started.

In the injection mode, the voltage applied to the magnetostrictive coil 21 is turned off and the valve is opened. When turning off the voltage applied to the magnetostrictive coil 21 at time t _3, the energization current of the magnetostrictive coil 21 is attenuated, the displacement of the magnetostrictive element enters the open state decreases. At time t ₄ , the lift amount of the entire valve 22 is maximized, and the valve is open.

In the valve closing mode, a voltage is applied to the magnetostrictive coil 21 to close the valve. At time _{t 5,} a voltage is applied to the magnetostrictive coil 21. Then, an energizing current flows through the magnetostrictive coil 21. As the energization current increases, the magnetostrictive element expands and the amount of displacement of the magnetostrictive element increases. The lift amount of the entire valve is reduced. Becomes a closed state at time t _6, the injection of fuel is stopped.

In the return mode, the voltage applied to both the holding coil 11 and the magnetostrictive coil 21 is turned off, the solenoid is restored, and the displacement of the magnetostrictive element is restored. At time t _7, it turns off the voltage applied to the holding coil 11. Then, as the energization current of the holding coil 11 decreases, the lift amount of the solenoid decreases due to the return force of the return spring 12. At time t _8, when turning off the voltage applied to the magnetostrictive coil 21, current supplied magnetostrictive coil 21 is attenuated, the displacement of the magnetostrictive element becomes small. At time t _9, the lift amount of the solenoid becomes zero, the flow returns to the state of the off mode.

FIG. 13 is an explanatory diagram showing the operation principle of another valve opening mode according to the first embodiment of the present invention. The explanatory view shown in FIG. 13 differs from the explanatory view shown in FIG. 5 in the operation of the valve opening mode. The off mode, the injection mode, the valve closing mode, and the return mode are the same as those in FIG. If the valve opening mode shown in FIG. 13, at time t _2, the voltage is applied to the magnetostrictive coil 21 first. Then, energization of the magnetostrictive coil 21 is started and an energization current flows. The current rises linearly with the inductance of the magnetostrictive coil 21 as a gradient, but gradually rises because the magnetic permeability is non-linear. As the energization current increases, the magnetostrictive element expands and the amount of displacement increases. At time t ₁₀ , a voltage is applied to the holding coil 11. Then, an energizing current flows through the holding coil 11. As the energization current increases, the solenoid starts to lift. At time t ₃ , the solenoid armature 14 is attracted and held by the holding coil 11, and the magnetostrictive element is expanded by the magnetic field generated by the energizing current and the displacement amount is increased. Since the lift amount of the solenoid and the displacement amount of the magnetostrictive element are offset, the lift amount of the entire valve is zero and the valve is closed. As shown in FIG. 13, in the valve opening mode, energization by the applied voltage to the magnetostrictive coil 21 may be started and then energization by the applied voltage to the holding coil 11 may be started.

In describing the operation of the driving circuit shown in FIGS. 6-9, 5, the operation period of time _{t 3} from time _{t 2} OP1, time _{t 3} the operation period of time _{t 5} from OP2, the time _{t 5} the period of time _{t 8} and the operation OP3 from.

  FIG. 6 is an explanatory diagram showing the expansion control of the magnetostrictive element in the valve opening mode. In operation OP1, in order to extend the length of the magnetostrictive element, it is necessary to apply a voltage to the magnetostrictive coil 21 and to pass an energizing current. The energization power source for the magnetostrictive coil 21 includes a first boost power source 32, a second boost power source 33, and a 12V power source 34.

  In order to apply a voltage to the magnetostrictive coil 21, the voltage of the first boost power supply 32 is applied to the switch SW 24 by an ON command signal from the boost open driver terminal 44. Alternatively, the voltage of the second boosting power source 33 is applied to the switch SW23 by an ON command signal from the boosting close driver terminal 45. Alternatively, the voltage of the 12V power supply 34 is applied to the switch SW22 by an ON command signal from the 12V system driver terminal 46. When a voltage is applied to the magnetostrictive coil 21, an energization current flows through the magnetostrictive coil 21 by turning on the switch SW <b> 21 in response to an on command signal from the low-side driver terminal 47. Note that it is preferable to control the first booster power source 32, the second booster power source 33, and the 12V power source 34 in accordance with the required specification speed of the expansion operation of the magnetostrictive element and the specification requirement of countermeasures for bounce of the valve.

  In general, the higher the voltage applied to the magnetostrictive coil 21, the faster the response of the magnetostrictive element. For example, the magnetostrictive element is first driven by the second highest voltage (150V in this example). The drive voltage may be switched to a voltage (for example, the first voltage or 12V) sufficient to maintain the desired displacement amount after quickly displacing to the desired displacement amount. As a result, the fuel injection valve can be operated at high speed while suppressing power consumption.

  FIG. 7 is an explanatory diagram showing contraction control of the magnetostrictive element in the injection mode. In operation OP2, in order to contract the length of the magnetostrictive element, it is necessary to turn off the voltage applied to the magnetostrictive coil 21 and cut off the energization current. The case where the switch SW24 is turned on and the energization current to the magnetostrictive coil 21 from the first step-up power supply 32 is cut off will be described. The switch SW24 is turned off by an off command signal from the boost open driver terminal 44. The coil energization current to the magnetostrictive coil 21 does not become zero immediately after the applied voltage is turned off, and the current continues to flow. Therefore, when the voltage application to the magnetostrictive coil 21 is turned off, the coil conduction current is turned off from the low-side driver terminal 47. The switch SW21 is turned off by the command signal. Then, the energization current flowing through R21 is commutated to the diode D21 side, so that the energization current can be rapidly attenuated and cut off.

  Even when the energization current to the magnetostrictive coil 21 from the second boosting power supply 33 is interrupted, the energization current to the magnetostrictive coil 21 can be interrupted by turning off the switch SW23 and the switch SW21.

  FIG. 8 is a circuit diagram showing a magnetostrictive element driving circuit according to another embodiment. In operation OP2, in order to contract the length of the magnetostrictive element, it is necessary to turn off the voltage applied to the magnetostrictive coil 21 and cut off the energization current. Another circuit configuration and operation for cutting off the energization current to the magnetostrictive coil 21 will be described.

  The magnetostrictive element drive circuit 20a shown in FIG. 8 differs from the magnetostrictive element drive circuit 20 shown in FIG. 4 in that the diode D21 is deleted and a Zener diode ZD21 is provided between the gate and drain of the switch SW21. When the switch SW24 is turned on and the energization current from the first boost power supply 32 to the magnetostrictive coil 21 is cut off, the switch SW24 and the switch SW21 are turned off. Then, the current to the magnetostrictive coil 21 can be rapidly cut off by the clamping operation by the Zener diode ZD21 and the FET.

  FIG. 9 is an explanatory diagram showing the expansion control of the magnetostrictive element in the valve closing mode. In operation OP3, in order to extend the length of the magnetostrictive element, it is necessary to apply a voltage to the magnetostrictive coil 21 and to pass an energizing current. In the valve closing mode, it may be required to close the valve in a short time. To close the valve in a short time, the second boosting power source 33 is set to a voltage higher than that of the first boosting power source 32, and a large current is rapidly passed through the magnetostrictive coil 21. By turning on the switch SW23 and turning on the switch SW21, a large current can be supplied to the magnetostrictive coil 21 from the second boosting power source 33.

  FIG. 10 is a flowchart showing the operation of the control unit of FIG. As shown in FIG. 10, in the valve opening mode, the solenoid coil 31 energizes the holding coil 11 (step S101), and the first booster power source 32 energizes the magnetostrictive coil 21 (step S102). The energization timings of step S101 and step S102 may be simultaneously or before and after so that the tip of the valve needle 15 is not separated from the seat 16. Further, bounce when the solenoid is lifted can be reduced by energizing the magnetostrictive coil 21 in step S102.

  In the injection mode, the energization to the magnetostrictive coil 21 is cut off (step S103). It is preferable to cut off the energized current rapidly for high-speed response of valve opening.

  In the valve closing mode, the magnetostrictive coil 21 is energized by the second boosting power source 33 (step S104). The second boost power source 33 is preferably set higher than the first boost power source 32. Thereby, a large current can be supplied to the magnetostrictive coil 21 and the valve can be closed at high speed.

  Further, by using a plurality of power supply voltages by the first boost power source 32 and the second boost power source 33, etc., energization to the magnetostrictive coil 21 in the valve open mode and to the magnetostrictive coil 21 in the valve close mode are performed. Can be energized with individual voltages. As a result, the use period of the high voltage can be shortened and the capacitor charging of the high-voltage power supply circuit can be completed in a short time, so that the valve can be opened and closed at high speed.

  In the return mode, the energization to the holding coil 11 is interrupted (step S105), and the energization to the magnetostrictive coil 21 is interrupted (step S106).

  FIG. 11 is a timing chart showing the fuel injection valve control method according to the first embodiment of the present invention. FIG. 11 shows waveforms of the control signals ((a) to (f)), the magnetostrictive coil current (g), the magnetostrictive element displacement (h), and the valve stroke (i) of each part. In each mode of FIG. 5, the valve opening / closing operation will be described in accordance with a command signal from the control unit 40.

During opening mode, at time t _11, the control unit 40, a higher-level control (e.g., the engine integrated control section) than, receives an ON command signal (corresponding to the drive circuit FD1.) Injector 1. Here, the ON command signal of the injector 1 is received from the host control unit here, but the control unit 40 may output the ON command signal of the injector 1.

Then, the control unit 40 at time t _12, the boosting open driver terminal 44 and the low side driver terminal 47 outputs an ON command signal. Energization of the magnetostrictive coil 21 is started, and displacement of the magnetostrictive element is started. Controller 40 at time t _13, and outputs an ON command signal to the solenoid driver.

Controller 40 at time t _14, and outputs an ON command signal to the 12V system driver terminal 46, and outputs an OFF command signal to the boosting open driver terminal 44. Here, the power source applied to the magnetostrictive coil 21 is switched from the first boost power source 32 to the 12V power source 34. Since the amount of displacement of the magnetostrictive element has already increased, the heat generation of the magnetostrictive coil 21 is reduced by reducing the energization current.

During the period from time t ₁₄ to time t ₁₅ , the control unit 40 outputs a PWM on / off signal to the low-side driver terminal 47. As a result, the energization current to the magnetostrictive coil 21 is turned on / off, and heat generation due to an excessive energization current is reduced.

In the injection mode, at time t ₁₅ , the control unit 40 outputs an off command signal to the 12V system driver terminal 46 and the low side driver terminal 47. The energizing current of the magnetostrictive coil 21 is cut off, the magnetostrictive element contracts, and the displacement amount of the magnetostrictive element returns to the initial state of the off mode. Therefore, the valve stroke of the valve 22 is opened. The fuel injection amount is determined by the degree of opening and closing of the valve and the opening and closing time. In the case of the present embodiment, since the valve opening due to the contraction of the magnetostrictive element can be performed at high speed, the injection amount can be precisely controlled.

In the valve closing mode, at time t ₁₆ , the control unit 40 outputs an ON command signal to the boost close driver terminal 45 and the low side driver terminal 47. The magnetostrictive coil 21 is supplied with current from the second boosting power source 33, and the amount of displacement of the magnetostrictive element increases at high speed. This is because the second boost power source 33 is a boost power source higher than the first boost power source 32. As the amount of displacement of the magnetostrictive element increases, the valve is closed. The fuel injection amount is determined by the degree of opening and closing of the valve and the opening and closing time. In the case of the present embodiment, since the valve closing due to the extension of the magnetostrictive element can be performed at a high speed, the injection amount can be precisely controlled.

At time t ₁₇ , the control unit 40 outputs an on command signal to the 12V system driver terminal 46 and outputs an off command signal to the boost close driver terminal 45. Here, the power source applied to the magnetostrictive coil 21 is switched from the second boost power source 33 to the 12V power source 34. Since the amount of displacement of the magnetostrictive element has already increased, the heat generation of the magnetostrictive coil 21 is reduced by reducing the energization current.

During a period from time t ₁₇ to time t ₁₈ , the control unit 40 outputs a PWM on / off signal to the low-side driver terminal 47. As a result, the energization current to the magnetostrictive coil 21 is turned on / off, and heat generation due to an excessive energization current is reduced.

At time t _18, the control unit 40, a higher-level control (e.g., the engine integrated control section) than, for receiving an off command signal (corresponding to the drive circuit FD1.) Injector 1.

In response to this, the control unit 40 returns enters mode, at time t _18, the solenoid driver outputs an OFF command signal to the boosting close driver terminal 45 and the low side driver terminal 47,. The solenoid is returned to the original state, the energization current to the magnetostrictive coil 21 is cut off, and the displacement amount of the magnetostrictive element returns to the initial state of the off mode.

  In the present embodiment, a plurality of different boosting power sources (first boosting power source 32 and second boosting power source 33) are used for energizing the magnetostrictive coil 21 in the valve opening mode and the valve closing mode. For this reason, the magnitude | size of an energization current can be changed and the expansion | extension time of a magnetostriction element can be controlled.

Also, if the repetition period of energization of the magnetostrictive coil 21 is short (for example, if the period of time t ₁₂ and time t ₁₆ is short) also in, by selectively using the plurality of boosted power supply can be energized .

Second embodiment.
FIG. 12 is a timing chart showing a fuel injection valve control method according to the second embodiment of the present invention. FIG. 12 shows waveforms of control signals ((a) to (f)), magnetostrictive coil current (g), magnetostrictive element displacement (h), and valve stroke (i) of each part. The waveform diagram shown in FIG. 12 is a case where the second injection mode is added to the waveform diagram shown in FIG. The second injection mode is a variable stroke mode in which the valve stroke is variable in order to adjust the fuel injection amount in the injection mode. The off mode, the valve opening mode, the injection mode, the valve closing mode, and the return mode are the same as those in FIG.

When the second injection mode, the control unit 40 at time t _21, the boosting open driver terminal 44 and the low side driver terminal 47 outputs an ON command signal. Energization of the magnetostrictive coil 21 is started, and displacement of the magnetostrictive element is started.

Controller 40 at time t _22, and outputs an ON command signal to the 12V system driver terminal 46, and outputs an OFF command signal to the boosting open driver terminal 44. Here, the power source applied to the magnetostrictive coil 21 is switched from the first boost power source 32 to the 12V power source 34. Since the amount of displacement of the magnetostrictive element has already increased, the heat generation of the magnetostrictive coil 21 is reduced by reducing the energization current.

During the period from time t ₂₂ to time t ₂₃ , the control unit 40 outputs a PWM on / off signal to the low-side driver terminal 47. Thereby, by turning on and off the energization current to the magnetostrictive coil 21, heat generation due to the energization current is reduced.

At time t ₂₃ from the time t _21, by changing the displacement of the magnetostrictive element, and by varying the valve stroke.

Controller 40 at time _{t 23,} and outputs an OFF command signal to the 12V system driver terminal 46 and the low side driver terminal 47. Then, the valve stroke returns to the injection mode.

  In the case of the present embodiment, the fuel injection amount can be adjusted by the variable stroke mode. This is because the displacement of the magnetostrictive element can be adjusted by energizing the magnetostrictive coil 21. As the power source in the variable stroke mode, the first boost power source 32 is used in the description shown in FIG. 11, but the second boost power source 33 or the 12V power source 34 may be used. Any current can be used as long as a current corresponding to the coil resistance of the magnetostrictive coil 21 is allowed to flow and the linear magnetostrictive element can be extended. In the variable stroke mode, it is preferable to use different power sources in consideration of the power source capacities of the first boost power source 32, the second boost power source 33, and the 12V power source 34.

  In the embodiments described above, the drive power supply 30 has been described as including the solenoid power supply 31, the first boost power supply 32, the second boost power supply 33, and the 12V power supply 34. However, the drive power supply included in the fuel injection valve control unit 100 is not necessarily limited to this configuration. In addition to the 12V voltage adjusted to an appropriate specification based on the voltage supplied from the battery, the solenoid voltage, the magnetostrictive coil Any configuration may be used as long as it can output the first voltage and the second voltage. In addition, the control signals for the switching elements of the drive circuit have been described as being supplied from the control unit 40 via the respective terminals for convenience of explanation, but these terminals are not necessarily required and can be omitted.

It is a block diagram which shows notionally the injector of the fuel-injection apparatus by the 1st Embodiment of this invention. It is a block diagram which shows the fuel injection valve control unit of the fuel injection apparatus by the 1st Embodiment of this invention. It is a circuit diagram which shows a solenoid drive circuit. It is a circuit diagram which shows a magnetostriction element drive circuit. It is explanatory drawing which shows the operation | movement principle of the fuel-injection apparatus by the 1st Embodiment of this invention. It is explanatory drawing which shows expansion | extension control of the magnetostriction element at the time of valve opening mode. It is explanatory drawing which shows contraction control of the magnetostriction element at the time of injection mode. It is a circuit diagram which shows the magnetostrictive element drive circuit by other embodiment. It is explanatory drawing which shows expansion | extension control of the magnetostriction element at the time of valve closing mode. It is a flowchart which shows operation | movement of the control part of FIG. It is a timing chart which shows the fuel injection valve control method by the 1st Embodiment of this invention. It is a timing chart which shows the fuel injection valve control method by the 2nd Embodiment of this invention. It is explanatory drawing which shows the operation principle of the other valve opening mode by the 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Solenoid drive circuit 11 Holding coil 12 Return spring 13 Fixing core 14 Armature 15 Valve needle 16 Seat 17 Injection hole 18 Solenoid 20 Magnetostrictive element drive circuit 21 Magnetostrictive coil 22 Valve 30 Drive power supply 31 Solenoid power supply 32 1st pressure | voltage rise power supply 33 Second boosting power supply 34 12V power supply 40 Control unit 100 Fuel injection valve control unit 200 Injector

Claims (8)

A control method of a fuel injection device for controlling a fuel injection valve using a solenoid and a magnetostrictive element as a driving force of a valve operating mechanism,
The fuel injection by energizing the solenoid coil for driving the solenoid and energizing the magnetostrictive coil of the magnetostrictive element using any one of a plurality of magnetostrictive element driving power sources for driving the magnetostrictive element A control method for a fuel injection device, characterized by controlling opening and closing of a valve. 2. The control method for a fuel injection device according to claim 1, wherein the displacement amount of the solenoid and the displacement amount of the magnetostrictive element are substantially equal. When the fuel injection valve is closed,
The method for controlling a fuel injection device according to claim 2, further comprising a first step of supplying a current to both the solenoid coil and the magnetostrictive coil to hold the fuel injection valve in a first state. . In the first state,
The method for controlling the fuel injection device according to claim 3, further comprising a step of opening the fuel injection valve by interrupting a current flowing through the magnetostrictive coil. In the opened state,
The method for controlling the fuel injection device according to claim 4, further comprising a valve closing step of closing the fuel injection valve by causing a current to flow through the magnetostrictive coil. As the plurality of magnetostrictive element driving power sources, a first power source that outputs a first voltage boosted from a predetermined voltage, and a second power source that outputs a second voltage higher than the first voltage boosted from a predetermined voltage. The method for controlling a fuel injection device according to any one of claims 1 to 5, wherein any one of the power sources is used. The fuel injection device according to claim 6, wherein the first step includes a step of causing a current to flow through the solenoid coil and a current to flow through the magnetostrictive coil using the first power source. Control method. 7. The fuel injection device according to claim 6, wherein the valve closing step includes a step of causing a current to flow through the magnetostrictive coil using the second power source to close the fuel injection valve. Control method.

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