JP2017075542A - Fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately control injection of an injector.SOLUTION: A fuel injection device 100 includes: an injector 100 for injecting fuel; a temperature determination section 50; and a correction section 50. The injector 10 includes a magnetic sensor 40 for detecting a change of a magnetic field caused by movement amount of a valve element and outputting a position signal corresponding to the detected change of the magnetic field. The temperature determination section 50 determines a fuel temperature in the injector 10 on the basis of the position signal at a predetermined position of the valve element 20 and temperature characteristics of the magnetic sensor 40. The correction section 50 corrects a drive signal for driving a driving section 30 on the basis of the fuel temperature determined by the temperature determination section 50.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel injection device including an injector for injecting fuel.

  Conventionally, in a fuel injection device for an internal combustion engine, high pressure fuel is injected into each cylinder of the engine using an injector. The injector includes a body having an injection hole for injecting fuel, a valve body that is accommodated in the body and opens and closes the injection hole, and a drive unit that reciprocates the valve body. When the control unit controls the drive unit, the opening / closing of the injection hole by the valve body is adjusted, and the amount of fuel injected from the injector, the injection timing, and the like change.

  Patent Document 1 discloses a configuration in which a magnet is attached to one end of a valve body, and the operating position of the valve body is detected based on a voltage change that occurs when the magnet passes through a coil. In addition, the control unit corrects the output voltage from the coil caused by the temperature change of the magnet to improve the detection accuracy of the operating position.

JP 2011-231697 PR

  When the fuel temperature in the injector is different, the density of the fuel, the atomized state of the fuel after injection, and the like change. In order to optimize the injection amount of the injector, it is desirable that the operation of the valve body can be controlled in consideration of the fuel temperature.

  The present invention has been made in view of the above problems, and an object thereof is to provide a fuel injection device capable of appropriately controlling injection of an injector.

  In order to solve the above-described problems, in the present invention, a body including an injection hole for injecting fuel, a valve body that is accommodated in the body and switches between opening and closing of the injection hole, and a drive unit that reciprocates the valve body And a magnetic sensor that detects a change in the magnetic field associated with the amount of movement of the valve body and outputs a position signal in accordance with the detected change in the magnetic field. And a temperature determination unit that determines a fuel temperature in the injector based on the position signal at a predetermined position of the valve body and a temperature characteristic of the magnetic sensor, and based on the determined fuel temperature A correction unit that corrects a drive signal for driving the drive unit.

  In the invention configured as described above, the magnetic sensor detects a change in the magnetic field associated with the amount of movement of the valve body, and outputs a position signal corresponding to the detected change in the magnetic field. A temperature determination part determines the fuel temperature in an injector based on the position signal according to the position of the predetermined valve body output from a magnetic sensor, and the temperature characteristic of a magnetic sensor. The correction unit corrects a drive signal for driving the drive unit based on the determined fuel temperature.

  Therefore, the temperature determination unit can determine the temperature of the fuel flowing through the injector from the position signal detected by the magnetic sensor. The correction unit corrects the drive signal for controlling the drive of the valve body based on the determined fuel temperature, thereby making it possible to optimize the injection of the injector.

1 is a diagram showing a schematic configuration of a fuel injection device 100. FIG. The figure explaining the relationship between the injection pulse INJ produced | generated in ECU50, and the injection of the injector. The figure explaining the output and temperature characteristic of the magnetic sensor 40. FIG. 7 is a flowchart in which the ECU 50 corrects the injection pulse INJ based on the fuel temperature TF in the injector 10. The figure explaining injection period Map and injection timing Map as an example. The perspective view which shows the shape of the magnetic sensor 140 which concerns on 2nd Embodiment.

  Hereinafter, an example of an embodiment of a fuel injection device according to the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the same reference numerals is used.

1. First Embodiment FIG. 1 is a diagram showing a schematic configuration of a fuel injection device 100. The fuel injection device 100 includes an injector 10, an ECU (ECU: Electronic Control Unit) 50, an NE sensor 53, and an accelerator position sensor 54. The injector 10 is mounted on a cylinder head of the engine, and injects fuel supplied from a common rail (pressure accumulation chamber) into the combustion chamber of each cylinder of the engine. In FIG. 1, only one injector 10 is shown for convenience, but actually, the fuel injection device 100 includes a number of injectors 10 corresponding to the number of cylinders of the engine.

  As the fuel, light oil, dimethyl ether (DME), biodiesel (BDF (registered trademark)), or synthetic oil obtained by synthesizing light oil and another fuel can be used. The fuel is preferably a non-magnetic material.

  Hereinafter, in a state where the injector 10 is mounted on the cylinder head, the side on which the injection hole of the injector 10 is formed is referred to as “lower side”, and the side opposite to the side on which the injection hole of the injector 10 is formed. Is described as “upper side”. “Valve opening direction D1” means a direction from the lower side to the upper side, and “Valve closing direction D2” means a direction from the upper side to the lower side.

  The injector 10 injects fuel, and includes a body 11, a needle valve 20, an urging member 24, a command piston 25, a drive unit 30, and a magnetic sensor 40. In this embodiment, the needle valve 20 functions as a valve body.

  The body 11 includes a fuel passage 12, a valve accommodating chamber 13, a nozzle hole 14, a pressure control chamber 15, and a leak flow path 16. The fuel passage 12 is a passage through which fuel flows inside the body 11, and is connected to a common rail (not shown) at the suction port. The valve housing chamber 13 has a lower diameter that is narrowed according to the diameter of the needle valve 20, and functions as a guide that holds the needle valve 20 slidably in the valve opening direction D1 and the valve closing direction D2. Further, the valve housing chamber 13 communicates with the fuel passage 12 on the lower side, and also functions as a hydraulic chamber in which the fuel pressure in the valve opening direction D1 is applied to the needle valve 20. The nozzle hole 14 is formed on the lower side of the body 11 and is a hole through which fuel is injected, and communicates with the valve housing chamber 13. The pressure control chamber 15 communicates with the fuel passage 12 and applies a fuel pressure in the valve closing direction D <b> 2 to the needle valve 20. The pressure control chamber 15 communicates with the leak channel 16 through the orifice 17. The leak channel 16 is a channel through which return fuel from the pressure control chamber 15 flows, and is connected to a fuel tank (not shown).

  The needle valve 20 is a member that switches the injector 10 between a valve closing state and a valve opening state by reciprocating in the valve opening direction D1 and the valve closing direction D2, and includes a sliding portion 21, a tip portion 22, And a detection unit 23. The sliding portion 21 is formed of a cylindrical member having a part of different diameters, and is accommodated in the valve accommodating chamber 13 so as to be slidable in the valve opening direction D1 and the valve closing direction D2. The distal end portion 22 is a truncated cone-shaped portion formed on the lower side of the sliding portion 21 and is accommodated in the valve accommodating chamber 13 while being directed to the injection hole 14. The detected portion 23 is a target portion for detecting the reciprocation of the needle valve 20, and is located on the upper side of the sliding portion 21. The detected part 23 is constituted by a cylindrical part having a diameter larger than that of the sliding part 21. The shape of the portion to be detected 23 is not limited to that shown in FIG. 1 and may be any shape as long as the reciprocation of the needle valve 20 is detected.

  An urging member 24 that applies an urging force in the valve closing direction D <b> 2 to the needle valve 20 is disposed on the upper side of the valve accommodating chamber 13. The biasing member 24 includes, for example, a pressure pin and a return spring.

  The pressure control chamber 15 accommodates a command piston 25 that slides in the valve opening direction D1 and the valve closing direction D2 in accordance with changes in internal fuel pressure. When the fuel pressure in the pressure control chamber 15 is maintained at a predetermined value, the command piston 25 applies a force in the valve closing direction D <b> 2 to the needle valve 20 via the biasing member 24. On the other hand, when the fuel pressure in the pressure control chamber 15 becomes a predetermined value or less, the command piston 25 slides in the valve opening direction D1. As a result, the fuel pressure in the valve storage chamber 13 exceeds the fuel pressure in the pressure control chamber 15, and a force in the valve opening direction D <b> 1 is applied to the needle valve 20.

  The driving unit 30 causes a pressure change in the pressure control chamber 15 and includes a valve 31 and a solenoid 32. The valve 31 switches between opening and closing of the orifice 17 of the pressure control chamber 15 by sliding in the valve opening direction D1 and the valve closing direction D2. The solenoid 32 changes the fuel pressure in the pressure control chamber 15 by sliding the valve 31 based on the control by the ECU 50. When the valve 31 opens the orifice 17 of the pressure control chamber 15, the fuel in the pressure control chamber 15 flows into the leak passage 16, and the fuel pressure in the pressure control chamber 15 is reduced.

  The injector 10 has been described by taking a solenoid type in which the drive unit 30 includes the solenoid 32 as an example. However, the injector 10 may be a piezo type in which the drive unit 30 includes a piezo element. In this case, the command piston 25 slides with the displacement of the piezo element, and the fuel pressure is changed in the pressure control chamber 15.

  The magnetic sensor 40 detects the amount of movement of the needle valve 20 based on a change in the magnetic field, and outputs an output voltage (position signal) corresponding to the amount of movement. The fixed unit 41, the magnetic field generating unit 42, , And a detection element 45. In the first embodiment, the magnetic sensor 40 is disposed in the valve accommodating chamber 13 of the injector 10 and detects the amount of movement of the detected portion 23 as the needle valve 20 slides.

  The fixing unit 41 fixes the magnetic field generation unit 42 and the detection element 45 to the valve accommodating chamber 13 of the body 11. For example, the fixed portion 41 is configured by an annular nonmagnetic member having an inner diameter larger than the inner diameter of the valve storage chamber 13. A magnetic field generation unit 42 and a detection element 45 are disposed on the inner peripheral side of the fixed unit 41. In FIG. 1, the fixed portion 41 is disposed so as to be embedded in the wall portion of the valve accommodating chamber 13 so that the detected portion 23 of the needle valve 20 can pass inside the fixed portion 41.

  The magnetic field generator 42 is a member that generates a magnetic field around the detected portion 23, and has magnets 43 and 44 having different magnetic pole directions (in FIG. 1, the magnet 43 has an N pole and the magnet 44 has an S pole). .). The magnet 43 and the magnet 44 are fixed to the inner peripheral side of the fixing portion 41 so as to be arranged in the reciprocating direction of the needle valve 20. Therefore, a magnetic force line (magnetic field) from the magnet 43 toward the magnet 44 is generated inside the fixed portion 41. Note that the magnet 43 as the N pole and the magnet 44 as the S pole are merely examples, and the magnet 43 may be the S pole and the magnet 44 may be the N pole.

  The detection element 45 detects a change in magnetic field lines (magnetic field) generated by the magnetic field generator 42 and outputs an output voltage VH. The detection element 45 is fixed to the inner peripheral side of the fixing portion 41 so as to be positioned between the magnet 43 and the magnet 44 in the sliding direction. The detection element 45 is disposed on the fixed portion 41 with the sensing surface facing the needle valve 20. The output terminal of the detection element 45 is connected to the ECU 50 and outputs a change in the lines of magnetic force generated by the magnetic field generator 42 to the ECU 50 as an output voltage VH.

  For example, the detection element 45 is configured by a Hall element or a magnetoresistive element (MR sensor).

  In this embodiment, the magnetic field generator 42 (magnet 43) is located between the drive unit 30 (solenoid 32) and the detection element 45 in the sliding direction of the needle valve 20. By positioning the magnetic field generation unit 42 between the solenoid 32 and the detection element 45, it is possible to prevent the detection element 45 from erroneously detecting the magnetic field generated from the solenoid 32.

  The ECU 50 controls the injection of the injector 10, and includes a control unit 51 and an electronic driving unit (EDU: Electronic Driving Unit) 52. In this embodiment, the ECU 50 is provided with the EDU 52, but the ECU 50 and the EDU 52 may be configured separately.

  The control unit 51 is mainly composed of a microcomputer mainly including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a rewritable nonvolatile memory such as a flash memory, and an input / output interface. It is configured. The control unit 51 is connected to the magnetic sensor 40, the NE sensor 53, the accelerator position sensor 54, and the like, and stores the output from each sensor in the RAM or the ROM or flash memory based on the output from the sensor. The control program stored in the program can be executed. When the control unit 51 executes the control program, an injection pulse INJ that is a drive signal for controlling fuel injection by the injector 10 can be output.

  The EDU 52 controls the state of the drive current DRC generated in the injector 10 (drive unit 30) based on the injection pulse INJ output from the control unit 51. For example, the EDU 52 controls driving of a high voltage generation circuit that generates a high voltage to be supplied to the drive unit 30, a plurality of switching elements for switching the injector 10 that supplies a high voltage, and driving of the high voltage generation circuit and the switching elements. Has a microcomputer. When the EDU 52 receives the injection pulse INJ, the EDU 52 applies this high voltage to the injector 10 to be injected and generates a drive current DRC.

  The NE sensor 53 detects a pulsar gear indicating the rotation angle of the crankshaft and outputs a crank angle signal NE corresponding to the crank angle. The accelerator position sensor 54 is attached to the accelerator unit and outputs an accelerator signal (VACCP) corresponding to the amount of depression of the accelerator.

  In the non-injection state of the injector 10, the EDU 52 does not apply a high voltage to the drive unit 30, and the drive current DRC does not flow through the drive unit 30. Therefore, the fuel pressure difference between the pressure control chamber 15 and the valve storage chamber 13 does not occur in the injector 10, and the force in the valve closing direction D <b> 2 is applied to the needle valve 20 by the command piston 25 and the biasing member 24 (closed). Valve state). On the other hand, in the injection state of the injector 10, the EDU 52 applies a high voltage to the drive unit 30, and a drive current DRC flows through the drive unit 30. For this reason, the solenoid 32 slides the valve 31 in the valve opening direction D <b> 1 and makes the fuel pressure in the pressure control chamber 15 lower than the fuel pressure in the valve storage chamber 13. As a result, force in the valve opening direction D1 is applied to the needle valve 20, and the needle valve 20 slides in the valve opening direction D1 (valve open state).

  Next, the relationship between the injection pulse INJ generated in the ECU 50 and the injection of the injector 10 will be described with reference to FIG. FIG. 2A shows the waveform of the ejection pulse INJ. FIG. 2B is a diagram illustrating a waveform of the drive current DRC that flows through the drive unit 30. FIG. 2C shows a waveform of the output voltage VH of the magnetic sensor 40. FIG. 2 (d) is a diagram for explaining the state of the injector 10 (the valve closed state and the valve open state).

  Hereinafter, a state where the needle valve 20 does not block the nozzle hole 14 is also referred to as a fully opened state, and a state where the needle valve 20 blocks the nozzle hole 14 is described as a fully closed state. Further, the change in the position of the detected portion 23 of the needle valve 20 in the reciprocating direction (sliding direction) from the fully closed state to the fully open state is also referred to as a lift amount ΔL. For example, in FIG. 2D, the lift amount ΔL indicates a change in the height of the lower surface of the detected portion 23. Needless to say, the reference position of the lift amount ΔL is not limited to that described in FIG. 2D, and the reference position may be set as appropriate.

  As shown in FIG. 2A, the injection pulse INJ sets a non-injection period in which the injector 10 does not inject fuel in the Low state, and sets an injection period in which the injector 10 injects fuel in the Hi state. The rising timing of the injection pulse INJ defines the injection timing INT indicating the valve opening timing of the injector 10, and the wavelength of the injection pulse INJ defines the injection period INP indicating the period during which fuel is injected. When the ECU 50 advances the rising timing of the injection pulse INJ, the timing at which the driving current DRC is generated advances, and by delaying the rising timing, the timing at which the driving current DRC is generated is delayed. Further, the ECU 50 increases the wavelength of the injection pulse INJ to increase the period in which the drive current DRC flows, and shortening the wavelength decreases the period in which the drive current DRC flows.

  The wavelength and rise time that define the waveform of the injection pulse INJ are defined in synchronization with the crank angle of the engine. The control unit 51 sets the wavelength and rising timing of the injection pulse INJ based on a crank angle signal NE output from the NE sensor 53 and an output from a timer (not shown).

  As shown in FIG. 2B, the waveform of the drive current DRC generated by the ejection pulse INJ includes a large current portion RC and a constant current portion CC. The large current portion RC is set to secure energy necessary for the solenoid 32 to slide the needle valve 20 in the fully closed state in the valve opening direction D1, and is set by a predetermined current value. Yes. The constant current portion CC is set to continue the position of the needle valve 20 after the generation of the large current portion RC, and is set with a current value lower than that of the large current portion RC. Further, the fluctuation range of the constant current portion CC is smaller than that of the large current portion RC.

  As shown in FIGS. 2C and 2D, when the needle valve 20 slides in the body 11, the magnetic sensor 40 senses a change in the magnetic lines of force accompanying the lift amount ΔL, and outputs an output voltage VH to the ECU 50. Since the lift amount ΔL of the needle valve 20 in the fully closed state is 0, the output voltage VH maintains a low value. When the drive current DRC is the large current portion RC, the needle valve 20 slides in the valve opening direction D1, and the lift amount ΔL increases. As a result, the output voltage VH from the magnetic sensor 40 increases. When the drive current DRC changes to the constant current portion CC, the lift amount ΔL of the needle valve 20 does not change and the output voltage VH becomes constant. Thereafter, when the generation of the drive current DRC stops, the needle valve 20 slides in the valve closing direction D2, and the output voltage VH decreases.

  Next, the output and temperature characteristics of the magnetic sensor 40 will be described with reference to FIG. FIG. 3A shows the relationship between the change in the lift amount ΔL of the needle valve 20 at the temperature T 0 and the output voltage VH output from the detection element 45. FIG. 3B shows the temperature characteristic of the detection element 45 at an arbitrary lift amount (ΔL0 in the figure).

  The magnetic sensor 40 has temperature characteristics, and the output voltage VH varies according to changes in the temperature T. FIG. 3A shows the output characteristics of the magnetic sensor 40 at a certain temperature (T0). When the temperature is the same, the input (lift amount ΔL) and the output (output voltage VH) maintain the same relationship. . On the other hand, due to the temperature characteristics of the magnetic sensor 40, even if the input is the same (lift amount ΔL), the same output (output voltage VH) is not obtained if the temperature is different. In FIG. 3B, the corresponding output voltage VH decreases as the temperature changes in the order of T1, T0, and T2.

  If the output voltage VH and the lift amount ΔL are determined in advance, the temperature around the magnetic sensor 40 can be determined by using this temperature characteristic. Therefore, in this embodiment, the ECU 50 determines the fuel temperature TF in the injector 10 based on the output voltage VH from the magnetic sensor 40, and corrects the injection pulse INJ using the determined fuel temperature TF. .

  Next, a process in which the ECU 50 corrects the injection pulse INJ based on the fuel temperature TF in the injector 10 will be described with reference to FIG. In the flowchart shown in FIG. 4, the ECU 50 functions as a temperature determination unit in step S12, and functions as a correction unit in steps S15 and S16.

  In step S11, the ECU 50 reads engine operating conditions. The engine operating conditions are various conditions required for operating an engine that is an internal combustion engine, and include an intake air amount, an intake air pressure, a cooling water temperature, and the like. For example, these engine operating conditions are detected by sensors (not shown) (air flow meter, intake pressure sensor, water temperature sensor) connected to the ECU 50 and managed by the ECU 50.

  In step S12, the ECU 50 determines whether or not the needle valve 20 has reached the position (lift amount ΔL) for determining the fuel temperature TH. For example, the ECU 50 stores a period in which the lift amount ΔL of the needle valve 20 is in a fully closed state, and determines whether or not the present time corresponds to this period. In the fully closed state, the lift amount ΔL is constant, so that it is possible to acquire the output voltage VH with little fluctuation. Since the lift amount ΔL of the needle valve 20 is synchronized with the crank angle, the ECU 50 currently corresponds to the closed state based on the crank angle obtained from the output from the NE sensor 53 and the count amount by the timer. It is determined whether or not.

  In step S12, the ECU 50 may use a fully opened state as a position for determining the fuel temperature TH. For example, if the drive current DRC is in the constant current portion CC in the fully open state, the lift amount ΔL is constant, so that it is possible to acquire the output voltage VH with little fluctuation.

  If the lift amount ΔL of the needle valve 20 is not at the position for determining the fuel temperature TH (step S12: NO), the ECU 50 delays until the lift amount ΔL reaches a predetermined position.

  If the lift amount ΔL of the needle valve 20 is a position for determining the fuel temperature TH (step S12: YES), the ECU 50 reads the output voltage VH from the magnetic sensor 40 in step S13. The reading of the output voltage VH in step S13 may be performed a plurality of times and an average may be taken.

  In addition, after the fully closed state is determined, the output voltage VH from the magnetic sensor 40 may be read by moving the needle valve 20 by a certain lift amount ΔL in step S13.

  In step S14, the fuel temperature TF is determined based on the output voltage VH. The ECU 50 determines the fuel temperature TF of the injector 10 based on the value of the output voltage VH read in step S12 and the temperature characteristics of the magnetic sensor 40. Acquisition of the temperature characteristic of the magnetic sensor 40 is performed using, for example, the temperature characteristic Map stored in the ECU 50. In the temperature characteristic Map1, as shown in FIG. 3B, the relationship between the output voltage VH and the fuel temperature TH at a specific lift amount ΔL is stored.

  In step S15, the ECU 50 corrects the injection period INP of the injection pulse INJ based on the fuel temperature TF determined in step S14. For example, the ECU 50 stores the injection period Map indicating the relationship between the fuel temperature TF and the injection period INP, and corrects the injection period INP of the injection pulse INJ by referring to the value stored in the injection period Map. .

  FIG. 5A is a diagram illustrating an injection period Map as an example. The injection period Map defines the correspondence between the fuel temperature TF and the injection period INP, and a value is defined such that the injection period INP becomes longer as the fuel temperature TF determined in step S12 increases. Since the fuel density decreases as the fuel temperature TF increases, the injection amount decreases even during the same injection period INP. In order to suppress the variation in the injection amount according to the change in the fuel temperature TF, a value is defined in the injection period Map so that the injection period TP becomes longer as the fuel temperature TF becomes higher.

  In the injection period Map, each value is defined so that the relationship between the fuel temperature TF and the injection period INP changes according to the change in the command injection pressure output from the ECU 50. The command injection pressure is determined according to the engine condition read in step S11. As the command injection pressure decreases, the injection amount decreases even during the same injection period INP. Therefore, the injection period Map defines a value such that the injection period INP corresponding to the fuel temperature TF becomes longer as the command injection pressure decreases.

  In step S16, the ECU 50 corrects the injection timing INT of the injection pulse INJ based on the fuel temperature TF acquired in step S14. For example, the ECU 50 stores an injection timing Map indicating the relationship between the fuel temperature TF and the injection timing INT, and corrects the injection timing INT of the injection pulse INJ based on the value stored in the injection timing Map.

  FIG. 5B is a diagram illustrating an injection timing Map as an example. The injection timing Map stores the correspondence between the fuel temperature TF and the injection timing INT, and is specified such that the injection timing INT advances (earlies) as the fuel temperature TF determined in step S12 increases. . As the fuel temperature TF increases, the fuel density decreases, and the injection amount decreases even during the same injection period INP. In order to suppress the variation in the injection amount according to the change in the fuel temperature TF, the injection timing Map defines the value so that the injection timing INT is advanced as the fuel temperature TF increases.

  Further, in the injection period Map, a value is defined such that the relationship between the fuel temperature TF and the injection period INP changes according to a change in the load of the internal combustion engine. Since the required fuel consumption decreases as the load decreases, the injection period Map stipulates that the injection timing INT corresponding to the fuel temperature TF is delayed as the load decreases.

  In this embodiment, the injection timing INT is corrected only from the fuel temperature TF. However, the present invention is not limited to this, and the injection timing INT is corrected using the fuel temperature TF and the lift amount ΔL. Also good.

  In step S17, the control unit 51 outputs the corrected injection pulse INJ corrected in steps S15 and S16 to the EDU 52. The EDU 52 drives the drive unit 30 of the injector 10 in accordance with the waveform of the corrected injection pulse INJ from the control unit 51 to inject fuel.

  In the first embodiment as described above, the ECU 50 determines the fuel temperature TF from the output voltage VH from the magnetic sensor 40, and appropriately controls the driving of the needle valve 20 based on the determined fuel temperature. It becomes possible to do. Since the object to be determined by the magnetic sensor 40 is the fuel temperature TF in the injector 10, the correction amount is more suitable for the fuel temperature TF than in the case of determining the fuel temperature TF from the temperature outside the injector 10. It can be.

  The magnetic sensor 40 includes a detected portion 23 provided in the needle valve 20, a magnetic field generation unit 42 that is disposed in the body 11 and generates a magnetic field, and a magnetic field that is disposed in the body 11 and is generated by the magnetic field generation unit 42. And a detecting element 45 for detecting a change in the. By setting it as the said structure, the magnetic field generation | occurrence | production part 42 which generate | occur | produces a magnetic field will be arrange | positioned in the body 11 side instead of the needle valve 20, and the weight increase of the needle valve 20 can be suppressed. As a result, the responsiveness of the needle valve 20 with respect to the action of the drive unit 30 can be increased.

  The drive unit 30 reciprocates the needle valve 20 by a solenoid 32 disposed on the opposite side to the end of the needle valve 20 that opens and closes the nozzle hole 14, and the magnetic field generation unit 42 includes the solenoid 32 and the detection element 45. Is located between. With the above configuration, the magnetic field generation unit 42 is positioned between the solenoid 32 that reciprocates the needle valve 20 and the detection element 45, and the detection element 45 erroneously detects the magnetic field generated from the solenoid 32. Can be suppressed. As a result, a change in the position of the needle valve can be detected with higher accuracy.

  The ECU 50 (temperature determination unit) determines the fuel temperature VF using the output voltage VH when the needle valve 20 is in the fully closed or fully opened position. With the above configuration, the fuel temperature TF can be determined based on the output voltage VH when the signal waveform is stable. As a result, the fuel temperature TF can be determined with higher accuracy. Further, by using the output voltage VH in the fully closed state for the temperature determination, the fuel temperature VF immediately before the injector 10 injects the fuel can be determined, and a sudden change in the fuel temperature VF immediately before the fuel injection occurs. Even if it occurs, this temperature change can be associated with the correction.

  The ECU 50 (correction unit) corrects the drive signal so that the injection period becomes longer as the determined fuel temperature VF becomes higher. By setting it as the said structure, the dispersion | variation in the injection amount accompanying the change of the fuel temperature VF can be suppressed.

  The ECU 50 (correction unit) corrects the drive signal so that the injection timing is advanced as the determined fuel temperature VF increases. By setting it as the said structure, the dispersion | variation in the injection amount accompanying the change of the fuel temperature VF can be suppressed.

2. Second Embodiment In the fuel injection device 100 according to the second embodiment, the configuration of the magnetic sensor is different from that of the first embodiment. FIG. 6 is a perspective view showing the shape of the magnetic sensor 140 according to the second embodiment.

  The magnetic sensor 140 includes a detection element 141 and a magnetic field generation unit 142 that generates a magnetic field and fixes the detection element 141. The magnetic field generator 142 is configured by an annular member having an inner diameter larger than the inner diameter of the valve storage chamber 13. The magnetic field generation unit 142 is disposed so as to be embedded in the wall of the valve storage chamber 13 so that the detected unit 23 can pass inside the magnetic field generation unit 142. The detection element 141 is disposed below the magnetic field generation unit 142 with the sensing surface facing the needle valve 20, and can detect a change in the magnetic field generated by the magnetic field generation unit 142. Further, the magnetic field generator 142 is located between the solenoid 32 and the detection element 45 in the sliding direction of the needle valve 20.

  The magnetic field generation unit 142 does not have to be magnetized in all of the annular portion, and may magnetize only a portion near the detection element 141.

  In the fuel injection device 100 according to the second embodiment, the magnetic field generation unit 142 is formed in an annular shape, so that the generated magnetic field is strengthened, and the detection element 45 detects a change in the magnetic field accompanying the sliding of the needle valve 20. Can be made easier. In addition, since the magnetic field generation unit 142 has a function as a fixing unit, a separate fixing unit is not required, and thus the configuration of the magnetic sensor 140 can be further simplified.

3. Third Embodiment The injector 10 is not limited to the configuration according to the first and second embodiments described above. For example, the magnetic sensor may be configured to include a magnetic field generator disposed above the needle valve 20 and a detection circuit disposed above the valve storage chamber 13. For example, the detection circuit includes a coil disposed on the upper side of the valve storage chamber 13 and an amplification circuit that detects a current flowing through the coil. In the magnetic sensor according to the third embodiment, when the magnetic field generator passes through the inside of the coil in accordance with the sliding of the needle valve 20, the coil passes a current according to the change in the magnetic field. The amplifier circuit amplifies this current and outputs it to the ECU 50 as an output signal.

  In the fuel injection device 100 according to the third embodiment, even in the configuration in which the needle valve 20 is provided with a magnetic field generation unit, the operation and effect of the present invention can be achieved.

  DESCRIPTION OF SYMBOLS 10 ... Injector, 11 ... Body, 14 ... Injection hole, 20 ... Needle valve, 30 ... Drive part, 40 ... Magnetic sensor, 50 ... ECU, 100 ... Fuel-injection apparatus

Claims (7)

A body (11) having an injection hole (14) for injecting fuel, a valve body (20) housed in the body and switching the opening and closing of the injection hole, and a drive unit (30) for reciprocating the valve body And an injector (10) comprising:
The injector is provided with a magnetic sensor (40) that detects a change in the magnetic field associated with the amount of movement of the valve body and outputs a position signal according to the detected change in the magnetic field.
A temperature determination unit (50) for determining a fuel temperature in the injector based on the position signal at a predetermined position of the valve body and a temperature characteristic of the magnetic sensor;
A correction unit (50) for correcting a drive signal for driving the drive unit based on the determined fuel temperature;
A fuel injection device. The magnetic sensor is
A magnetic field generator (42) disposed in the body for generating a magnetic field;
The fuel injection device according to claim 1, further comprising a detection element (45) disposed on the body and configured to detect a change in magnetism generated by the magnetic field generation unit in accordance with the movement of the valve body. The drive unit reciprocates the valve body by a solenoid (32) disposed on an end side opposite to an end for opening and closing the nozzle hole of the valve body,
The fuel injection device according to claim 2, wherein the magnetic field generation unit is located between the solenoid and the detection element.   4. The fuel injection device according to claim 2, wherein the magnetic field generation unit has an annular shape, and the valve body is positioned to pass inside the magnetic field generation unit.   The fuel according to any one of claims 1 to 4, wherein the temperature determination unit determines the fuel temperature using the position signal when the valve body is in a fully closed position or a fully open position. Injection device.   The fuel injection device according to any one of claims 1 to 5, wherein the correction unit corrects the drive signal so that an injection period becomes longer as the determined fuel temperature becomes higher.   The fuel injection device according to any one of claims 1 to 5, wherein the correction unit corrects the drive signal so that an injection timing is advanced as the determined fuel temperature increases.

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