fuel injection device

Abstract

To reduce attachment of fuel to an injector.SOLUTION: A fuel injection device provided on an engine has: a nozzle portion having an injection hole for injecting a fuel; and a body portion on which a fuel flow channel for supplying the fuel to the injection hole is formed. The fuel injection device has a first electrode for charging internal fuel as the fuel in the fuel flow channel, and a second electrode for charging external fuel as the fuel attached to a tip of the nozzle portion. The fuel injection device has a power source circuit portion for applying voltage to the first electrode and the second electrode, and a control system for controlling the power source circuit portion. The injector includes a valve element moving to a close position for closing the injection hole and an open position for opening the injection hole, and the control system applies voltage to the first electrode and the second electrode to charge the internal fuel and the external fuel with polarities opposite to each other in a state where the valve element has moved to the close position.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a fuel injection device provided in an engine. [Background technology]

[0002] Fuel such as gasoline is injected into the combustion chamber or intake port of an engine from an injector (see Patent Documents 1 to 4). Furthermore, since engine exhaust gas contains particulate matter (PM), there is a demand for reducing the particulate number (PN) in the exhaust gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-25751 [Patent Document 2] Japanese Patent Publication No. 2020-110746 [Patent Document 3] Japanese Utility Model Application Publication No. 4-62341 [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-2629 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, one factor that increases the number of particulate matter contained in exhaust gas is a localized increase in the concentration of fuel injected from the injector. One factor that causes variations in the concentration of injected fuel is the presence of fuel adhering to the tip of the injector. In other words, if a large amount of fuel adheres to the tip of the injector, this adhered fuel may condense and leave the injector, potentially causing a localized increase in the concentration of injected fuel.

[0005] An object of the present invention is to reduce fuel adhesion to the injector. [Means for solving the problem]

[0006] In one embodiment, a fuel injection device is provided in an engine, and includes: an injector having a nozzle portion formed with an injection hole for injecting fuel; and a main body portion formed with a fuel flow path that supplies fuel to the injection hole; a first electrode provided in the injector that charges internal fuel, which is fuel in the fuel flow path; a second electrode provided in the injector that charges external fuel, which is fuel adhering to the tip of the nozzle portion; a power supply circuit portion electrically connected to the first electrode and the second electrode and applying a voltage to the first electrode and the second electrode; and a control system having a processor and memory communicatively connected to each other and controlling the power supply circuit portion, wherein the injector has a valve body that moves between a closed position that closes the injection hole and an open position that opens the injection hole, and the control system applies a voltage to the first electrode and the second electrode when the valve body is moved to the closed position, thereby charging the internal fuel and the external fuel with opposite polarities to each other. [Effects of the Invention]

[0007] According to one aspect of the present invention, the internal fuel and the external fuel are charged to opposite polarities, thereby reducing the amount of fuel adhering to the injector. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of a vehicle equipped with an engine. [Figure 2] FIG. 1 is a diagram illustrating an example of an engine. [Figure 3] FIG. 2 is a diagram illustrating an example of an injector that constitutes a fuel injection device. [Figure 4] 4A and 4B are diagrams illustrating the operating states of the injector. [Figure 5] FIG. 2 is a diagram illustrating an example of a control system that configures the fuel injection device. [Figure 6]FIG. 2 is a diagram illustrating an example of a basic structure of an engine control unit. [Figure 7] 4 is a flowchart showing an example of a procedure for executing fuel charging control. [Figure 8] 10A and 10B are diagrams illustrating a nozzle portion and its vicinity during the execution of fuel charging control. [Figure 9] 10A and 10B are diagrams illustrating a nozzle portion and its vicinity during the execution of fuel charging control. [Figure 10] 10 is a flowchart showing another example of the procedure for executing fuel charging control. [Figure 11] 10A and 10B are diagrams illustrating a nozzle portion and its vicinity during the execution of fuel charging control. [Figure 12] FIG. 10 is a diagram showing another example of an injector constituting a fuel injection device. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. In the following description, identical or substantially identical configurations and elements are designated by the same reference numerals and will not be described repeatedly.

[0010] [vehicle] FIG. 1 is a diagram showing an example of a vehicle 11 equipped with an engine 10. As shown in FIG. 1, the vehicle 11 is equipped with a powertrain 12 including the engine 10. The illustrated engine 10 is provided with a fuel injection device 13, which is an embodiment of the present invention. The vehicle 11 is also provided with a fuel tank 14 that stores fuel such as gasoline, and the fuel tank 14 and the engine 10 are connected to each other via a fuel supply path 15. As will be described later, the illustrated engine 10 is a horizontally opposed engine, but is not limited to this and may be an in-line engine, a V-type engine, or a single-cylinder engine.

[0011] [engine] Fig. 2 is a diagram showing an example of an engine 10. As shown in Fig. 2, the engine 10 has a cylinder block 20 that constitutes one cylinder bank, a cylinder block 21 that constitutes the other cylinder bank, and a crankshaft 22 supported by the pair of cylinder blocks 20, 21. A cylinder bore 23 is formed in each of the cylinder blocks 20, 21, and a piston 24 is housed in each of the cylinder bores 23. The crankshaft 22 and the piston 24 are connected to each other via a connecting rod 25.

[0012] A cylinder head 31 equipped with a valve train 30 and other components is attached to each cylinder block 20, 21. The cylinder head 31 is formed with an intake port 33 communicating with a combustion chamber 32, and is fitted with an intake valve 34 that opens and closes the intake port 33. The cylinder head 31 is also formed with an exhaust port 35 communicating with the combustion chamber 32, and is fitted with an exhaust valve 36 that opens and closes the exhaust port 35. The cylinder head 31 is also provided with an injector 37 that injects fuel into the combustion chamber 32, and is also provided with a spark plug (not shown) that ignites the air-fuel mixture in the combustion chamber 32.

[0013] [Injector] FIG. 3 is a diagram showing an example of an injector 37 constituting the fuel injection device 13. As shown in FIG. 3, the injector 37, which is mounted in the cylinder head 31, is connected to the fuel tank 14 via the fuel supply path 15. That is, the fuel injection device 13, which supplies fuel to the engine 10, is provided with the fuel tank 14 that stores fuel such as gasoline, and the injector 37 that injects the fuel into the combustion chamber 32. The fuel injection device 13 also has a low-pressure pump 40 provided in the fuel tank 14 and a high-pressure pump 42 connected to a distribution pipe 41 of the injector 37. The low-pressure pump 40 and the high-pressure pump 42 are connected via a fuel pipe 43, and the high-pressure pump 42 and the injector 37 are connected via a fuel pipe 44 and the distribution pipe 41. That is, the low-pressure pump 40, the fuel pipe 43, the high-pressure pump 42, the fuel pipe 44, and the distribution pipe 41 form the fuel supply path 15, and the fuel tank 14 and the injector 37 are connected to each other via this fuel supply path 15.

[0014] The injector 37 has a main body 50 that is attached to the cylinder head 31 of the engine 10, and a nozzle 51 that is provided at the tip of the main body 50. The main body 50 of the injector 37 has an inner pipe 53 that has a fuel flow path 52 formed therein. The inner pipe 53 is composed of a main pipe 53a, an intermediate pipe 53b, and a tip pipe 53c. An electromagnetic coil 54 is provided on the outside of the intermediate pipe 53b, and the electromagnetic coil 54 is held by a sub-holder 55. A main holder 56 is provided on the outside of the main pipe 53a, and the sub-holder 55 and the electromagnetic coil 54 are covered by the main holder 56. A connector 57 is formed on the main holder 56, and the connector 57 has a terminal 58 that is connected to the electromagnetic coil 54.

[0015] A cylindrical fixed core 60 made of a magnetic material is fixed inside an inner pipe 53 provided in the injector 37, and a cylindrical movable core 61 made of a magnetic material is housed therein so as to be reciprocable. An adjustment pipe 62 is provided inside the fixed core 60, and a needle valve (valve element) 63 is provided at the end of the movable core 61. A spring 64 is attached between the adjustment pipe 62 and the movable core 61, and this spring 64 urges the movable core 61 in a direction away from the fixed core 60. A nozzle portion 51 equipped with a valve seat 65 made of an insulating material is provided at the tip of the inner pipe 53. A plurality of injection holes 66 are formed in the valve seat 65, and a tip electrode (second electrode) 72 is attached to the end face of the valve seat 65. As indicated by the symbol α in FIG. 3, the tip electrode 72 is configured in a mesh shape with multiple meshes. Furthermore, an annular flow path electrode (first electrode) 71 is provided on the inner circumferential surface of a tip pipe 53c of the inner pipe 53, with an insulator 70 interposed therebetween. The connector 57 is provided with a terminal 71b connected to the flow path electrode 71 via a current carrying line 71a, and a terminal 72b connected to the tip electrode 72 via a current carrying line 72a.

[0016] The distribution pipe 41 of the fuel supply path 15 is connected to the inner pipe 53 of the injector 37. The fuel supplied from the distribution pipe 41 to the inner pipe 53 flows inside the main pipe 53a, the adjust pipe 62, the fixed core 60, and the movable core 61, and then reaches the inside of a needle valve 63 fixed to the movable core 61. A communication hole 63a is formed through the needle valve 63 in the radial direction, and the fuel that flows inside the needle valve 63 reaches the outside of the needle valve 63 through the communication hole 63a. In this way, the fuel supplied from the distribution pipe 41 to the inner pipe 53 flows through the fuel flow path 52 defined by the inside of the main pipe 53a, the adjust pipe 62, the fixed core 60, and the movable core 61, and then is supplied to a fuel chamber (fuel flow path) 73 defined by the tip pipe 53c, the movable core 61, the needle valve 63, and the valve seat 65. The fuel chamber 73 constitutes a part of the fuel flow path 52 provided in the injector 37. A filter 74 for removing foreign matter from the fuel is attached to the fuel flow path 52 in the main pipe 53a.

[0017] An injection hole 66 in a valve seat 65 is opened and closed by a needle valve 63. FIG. 4 shows the operating states of the injector 37. FIG. 4 illustrates an injection state in which the needle valve 63 moves to an open position and a stationary state in which the needle valve 63 moves to a closed position. When the electromagnetic coil 54 is energized by an engine control unit 83 (described later), a magnetic circuit is formed among the main pipe 53a, the fixed core 60, the movable core 61, the sub-holder 55, and the main holder 56. This generates a magnetic attraction force between the fixed core 60 and the movable core 61, attracting the movable core 61 toward the fixed core 60. In other words, the movable core 61 with the needle valve 63 moves toward the fixed core 60, and the needle valve 63 moves to an open position that opens the injection hole 66. On the other hand, when the electromagnetic coil 54 is de-energized, the magnetic attraction force between the fixed core 60 and the movable core 61 disappears, and the spring force of the spring 64 moves the movable core 61 away from the fixed core 60. That is, the movable core 61 having the needle valve 63 moves away from the fixed core 60, so that the needle valve 63 moves to the closed position where it closes the injection hole 66.

[0018] As described above, when the electromagnetic coil 54 is energized, the needle valve 63 moves to the open position away from the valve seat 65 due to electromagnetic attraction. When the injector 37 is in the injection state, the fuel chamber 73 and the injection holes 66 are in communication with each other, so that fuel in the fuel chamber 73 is injected from the injection holes 66. On the other hand, when the electromagnetic coil 54 is de-energized, the spring force moves the needle valve 63 to the closed position in which it contacts the valve seat 65. When the injector 37 is in the stopped state, the fuel chamber 73 and the injection holes 66 are blocked from each other by the needle valve 63, so that fuel is trapped in the fuel chamber 73 without being injected from the injection holes 66.

[0019] [Control System] FIG. 5 is a diagram showing an example of a control system 80 constituting the fuel injection device 13. As shown in FIG. 5, the fuel injection device 13 is provided with a power supply unit (power supply circuit section) 81 electrically connected to the tip electrode 72 and the flow path electrode 71. A battery 82 is connected to the power supply unit 81, and the power supply unit 81 incorporates a switching circuit 81a, a transformer 81b, a rectifier circuit 81c, a smoothing circuit 81d, and the like. The power supply unit 81 generates high-voltage DC power from the power supplied by the battery 82 and applies positive and negative voltages to the tip electrode 72 and the flow path electrode 71. That is, the power supply unit 81 is operable in a first operating state (operating state) in which a positive voltage is applied to the tip electrode 72 and a negative voltage is applied to the flow path electrode 71, and a second operating state (operating state) in which a negative voltage is applied to the tip electrode 72 and a positive voltage is applied to the flow path electrode 71.

[0020] The fuel injection device 13 is provided with a control system 80 consisting of an engine control unit 83 to control the operation of a power supply unit 81 connected to the injector 37 and to control the energization state of the electromagnetic coil 54 provided in the injector 37. Sensors connected to the engine control unit 83 include a vehicle speed sensor 84 that detects the vehicle speed, an accelerator sensor 85 that detects the amount of accelerator pedal operation, and a brake sensor 86 that detects the amount of brake pedal operation. Other sensors connected to the engine control unit 83 include a crank rotation sensor 87 that detects the rotation angle of the crankshaft, a water temperature sensor 88 that detects the temperature of the coolant for the engine 10, an airflow sensor 89 that detects the amount of intake air for the engine 10, and an air-fuel ratio sensor 90 that detects the air-fuel ratio from the oxygen concentration in the exhaust gas. The engine control unit 83 is also provided with a start switch 91 that is manually operated to start and stop the control system 80.

[0021] Fig. 6 is a diagram showing an example of the basic structure of the engine control unit 83. As shown in Fig. 6, the engine control unit 83, which is an electronic control unit, has a microcontroller 102 incorporating a processor 100 and a main memory (memory) 101. A predetermined program is stored in the main memory 101, and the program is executed by the processor 100. The processor 100 and the main memory 101 are connected to each other so that they can communicate with each other. Note that a plurality of processors 100 may be incorporated into the microcontroller 102, and a plurality of main memories 101 may be incorporated into the microcontroller 102.

[0022] The engine control unit 83 also includes an input circuit 103, a drive circuit 104, a communication circuit 105, an external memory 106, a power supply circuit 107, and the like. The input circuit 103 converts signals input from various sensors into signals that can be input to the microcontroller 102. The drive circuit 104 generates drive signals for various devices, such as the injector 37, based on signals output from the microcontroller 102. The communication circuit 105 converts signals output from the microcontroller 102 into communication signals directed to other electronic control units. The communication circuit 105 also converts communication signals received from other electronic control units into signals that can be input to the microcontroller 102. The power supply circuit 107 supplies a stable power supply voltage to the microcontroller 102, the input circuit 103, the drive circuit 104, the communication circuit 105, the external memory 106, and the like. The external memory 106, which may be a non-volatile memory or the like, stores programs, various data, and the like.

[0023] [Fuel charging control] FIG. 7 is a flowchart showing an example of the procedure for executing fuel charging control. Each step shown in the flowchart in FIG. 7 represents processing executed by processor 100 constituting control system 80. Note that the fuel charging control shown in FIG. 7 is control that is executed by control system 80 at predetermined intervals after control system 80 is activated and engine 10 is started. Also, FIGS. 8 and 9 are diagrams showing nozzle section 51 and its vicinity during the execution of fuel charging control. Note that in the following description, fuel within fuel chamber 73 will be referred to as internal fuel Fi, and fuel adhering to tip electrode 72 located at the tip of nozzle section 51 will be referred to as external fuel Fo.

[0024] As shown in FIG. 7 , when the needle valve 63 is controlled to the closed position in step S10, the process proceeds to step S11, where the power supply unit 81 is controlled to the first operating state, and the potential of the flow path electrode 71 is raised higher than the potential of the tip electrode 72. That is, a positive voltage is applied to the flow path electrode 71, while a negative voltage is applied to the tip electrode 72. As a result, as shown at time t1 in FIG. 8 , with respect to the internal fuel Fi contained in the fuel chamber 73, electrons move from the internal fuel Fi to the flow path electrode 71, decreasing the number of electrons in the internal fuel Fi and causing the internal fuel Fi to be positively charged. Also, with respect to the external fuel Fo attached to the tip of the nozzle portion 51, electrons move from the tip electrode 72 to the external fuel Fo, increasing the number of electrons in the external fuel Fo and causing the external fuel Fo to be negatively charged. That is, the internal fuel Fi and the external fuel Fo are charged with opposite polarities.

[0025] To charge the internal fuel Fi and the external fuel Fo with opposite polarities, a valve seat 65, which is an insulator with high electrical resistance, is provided between the flow path electrode 71 and the tip electrode 72. Although an insulator is provided between the fuel electrode and the tip pipe 53c, the electrical resistance of the tip pipe 53c, the movable core 61, and the needle valve 63 that define the fuel chamber 73 is also increased to efficiently charge the internal fuel Fi in the fuel chamber 73. For example, the electrical resistance of the tip pipe 53c and the like can be increased by applying an insulating coating treatment to the tip pipe 53c, the movable core 61, and the needle valve 63. It goes without saying that the tip pipe 53c, the movable core 61, and the needle valve 63 may also be formed using an insulating material.

[0026] 7, with the needle valve 63 moved to the closed position, the power supply unit 81 is controlled to a stopped state, and voltage application to the flow path electrode 71 and the tip electrode 72 is discontinued. Then, the process proceeds to step S13, where the needle valve 63 is controlled to the open position for a predetermined time, and then to step S14, where the needle valve 63 is controlled to the closed position. As a result, as shown at times t1 and t2 in FIG. 8, the positively charged internal fuel Fi is injected into the combustion chamber 32 from the injection hole 66 of the nozzle portion 51. At this time, the external fuel Fo adhering to the tip of the nozzle portion 51 is negatively charged, and the positively charged internal fuel Fi and the negatively charged external fuel Fo attract each other, so the positively charged internal fuel Fi is injected into the combustion chamber 32 while taking in the negatively charged external fuel Fo. Then, as shown at time t3, when the needle valve 63 is returned to the closed position, the positively charged fuel that has flowed out of the fuel chamber 73 adheres to the tip of the nozzle portion 51 as new external fuel Fo.

[0027] As shown in FIG. 7, in the subsequent step S15, the power supply unit 81 is controlled to the second operating state, and the potential of the tip electrode 72 is raised above the potential of the flow path electrode 71. That is, a negative voltage is applied to the flow path electrode 71, while a positive voltage is applied to the tip electrode 72. As a result, as shown at time t4 in FIG. 9, with respect to the internal fuel Fi accommodated in the fuel chamber 73, electrons move from the flow path electrode 71 to the internal fuel Fi, increasing the number of electrons in the internal fuel Fi and causing the internal fuel Fi to be negatively charged. Also, with respect to the external fuel Fo adhering to the tip of the nozzle portion 51, electrons move from the external fuel Fo to the tip electrode 72, decreasing the number of electrons in the external fuel Fo and causing the external fuel Fo to be positively charged. That is, the internal fuel Fi and the external fuel Fo are charged with opposite polarities.

[0028] 7, with the needle valve 63 moved to the closed position, the power supply unit 81 is controlled to a stopped state, and the voltage application to the flow path electrode 71 and the tip electrode 72 is discontinued. Then, the process proceeds to step S17, where the needle valve 63 is controlled to the open position for a predetermined time, and then to step S18, where the needle valve 63 is controlled to the closed position. As a result, as shown at times t4 and t5 in FIG. 8, the negatively charged internal fuel Fi is injected into the combustion chamber 32 from the injection hole 66 of the nozzle portion 51. At this time, the external fuel Fo adhering to the tip of the nozzle portion 51 is positively charged, and the negatively charged internal fuel Fi and the positively charged external fuel Fo attract each other, so the negatively charged internal fuel Fi is injected into the combustion chamber 32 while taking in the positively charged external fuel Fo. Then, as shown at time t6, when the needle valve 63 is returned to the closed position, the negatively charged fuel that has flowed out of the fuel chamber 73 adheres to the tip of the nozzle portion 51 as new external fuel Fo.

[0029] As described above, the control system 80 applies voltage to the flow path electrode 71 and the tip electrode 72 using the power supply unit 81 while the needle valve 63 is in the closed position, thereby charging the internal fuel Fi and the external fuel Fo with opposite polarities. This allows the external fuel Fo adhering to the tip of the nozzle portion 51 to be removed each time fuel is injected from the injection hole 66 of the nozzle portion 51, thereby preventing an excessive increase in the external fuel Fo. By preventing an excessive increase in the external fuel Fo, variations in the concentration of the fuel injected from the injector 37 can be reduced, thereby reducing the particulate number (PN) in the exhaust gas. Furthermore, removing the external fuel Fo adhering to the tip of the nozzle portion 51 prevents deposits from building up on the nozzle portion 51, thereby maintaining good fuel injection performance by the injector 37.

[0030] [Another embodiment 1] In the example shown in FIGS. 7 to 9, the internal fuel Fi is alternately charged positively and negatively, and the external fuel Fo is alternately charged negatively and positively, but this is not limiting. That is, in the example shown in FIGS. 7 to 9, the power supply unit 81 is controlled by switching between a first operating state, a stopped state, and a second operating state, in this order, but this is not limiting. For example, the power supply unit 81 may be controlled by switching between a first operating state and a stopped state, or may be controlled by switching between a second operating state and a stopped state. Here, FIG. 10 is a flowchart showing another example of the execution procedure for fuel electrification control. Each step shown in the flowchart in FIG. 10 represents processing executed by the processor 100 constituting the control system 80. Note that the fuel electrification control shown in FIG. 10 is control that is executed by the control system 80 at predetermined intervals after the control system 80 is activated and the engine 10 is started. Furthermore, FIG. 11 is a diagram showing the nozzle unit 51 and its vicinity during the execution of fuel electrification control.

[0031] As shown in FIG. 10 , when the needle valve 63 is controlled to the closed position in step S20, the process proceeds to step S21, where the power supply unit 81 is controlled to the first operating state, and the potential of the flow path electrode 71 is raised higher than the potential of the tip electrode 72. That is, a positive voltage is applied to the flow path electrode 71, while a negative voltage is applied to the tip electrode 72. As a result, as shown at time t11 in FIG. 11 , with respect to the internal fuel Fi contained in the fuel chamber 73, electrons move from the internal fuel Fi to the flow path electrode 71, decreasing the number of electrons in the internal fuel Fi and causing the internal fuel Fi to be positively charged. Also, with respect to the external fuel Fo attached to the tip of the nozzle portion 51, electrons move from the tip electrode 72 to the external fuel Fo, increasing the number of electrons in the external fuel Fo and causing the external fuel Fo to be negatively charged. That is, the internal fuel Fi and the external fuel Fo are charged with opposite polarities.

[0032] 10, with the needle valve 63 moved to the closed position, the power supply unit 81 is controlled to a stopped state, and voltage application to the flow path electrode 71 and the tip electrode 72 is discontinued. Then, the process proceeds to step S23, where the needle valve 63 is controlled to the open position for a predetermined time, and then to step S24, where the needle valve 63 is controlled to the closed position. As a result, as shown at times t11 and t12 in FIG. 11, the positively charged internal fuel Fi is injected into the combustion chamber 32 from the injection hole 66 of the nozzle portion 51. At this time, the external fuel Fo adhering to the tip of the nozzle portion 51 is negatively charged, and the positively charged internal fuel Fi and the negatively charged external fuel Fo attract each other, so the positively charged internal fuel Fi is injected into the combustion chamber 32 while taking in the negatively charged external fuel Fo. Then, as shown at time t13, when the needle valve 63 is returned to the closed position, the positively charged fuel that has flowed out of the fuel chamber 73 adheres to the tip of the nozzle portion 51 as new external fuel Fo.

[0033] Then, once the fuel is injected from the injection holes 66 of the nozzle portion 51, the process returns to step S21 in Fig. 10, the power supply unit 81 is controlled to the first operating state, a positive voltage is applied to the flow path electrode 71, and a negative voltage is applied to the tip electrode 72. As a result, as shown at time t14 in Fig. 11, with respect to the internal fuel Fi accommodated in the fuel chamber 73, electrons again move from the internal fuel Fi to the flow path electrode 71, decreasing the electrons in the internal fuel Fi and causing the internal fuel Fi to be positively charged. Also, with respect to the external fuel Fo adhering to the tip of the nozzle portion 51, electrons again move from the tip electrode 72 to the external fuel Fo, increasing the electrons in the external fuel Fo and causing the external fuel Fo to be negatively charged. In other words, the internal fuel Fi and the external fuel Fo are charged with opposite polarities.

[0034] In this way, even when the power supply unit 81 is controlled by switching between the first operation state and the stopped state, it is possible to charge the internal fuel Fi and the external fuel Fo with opposite polarities. That is, the internal fuel Fi can be positively charged, and the external fuel Fo can be negatively charged. This makes it possible to remove the external fuel Fo adhering to the tip of the nozzle portion 51 every time fuel is injected from the injection hole 66 of the nozzle portion 51, thereby suppressing an excessive increase in the external fuel Fo. Furthermore, by suppressing an excessive increase in the external fuel Fo, it is possible to suppress variations in the concentration of the fuel injected from the injector 37, and to reduce the number of particulate matter in the exhaust gas. It goes without saying that the internal fuel Fi may be negatively charged, and the external fuel Fo may be positively charged, by controlling the power supply unit 81 by switching between the second operation state and the stopped state.

[0035] [Another embodiment 2] 5, the flow path electrode 71 is provided on the tip pipe 53c in order to charge the internal fuel Fi contained in the fuel chamber 73, but this is not limitative and the flow path electrode 71 may be provided on another component exposed to the fuel chamber 73. Here, FIG. 12 is a diagram showing another example of the injector 37 that constitutes the fuel injection device 13.

[0036] 12, in the injector 110, a fuel chamber (fuel flow path) 73 is defined by the tip pipe 53c, the movable core 61, the needle valve 63, and the valve seat 65. In addition, an annular flow path electrode (first electrode) 111 is provided on the outer peripheral surface of the needle valve 63 via an insulator 112. Even when the flow path electrode 111 is provided on the needle valve 63 facing the fuel chamber 73 in this way, the internal fuel Fi can be positively charged by applying a positive voltage to the flow path electrode 111, and the internal fuel Fi can be negatively charged by applying a negative voltage to the flow path electrode 111.

[0037] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present invention. The illustrated engine 10 is a gasoline engine that uses gasoline as fuel, but the present invention is not limited to this, and the fuel injection device 13 according to an embodiment of the present invention may be applied to a diesel engine that uses diesel fuel. Furthermore, the illustrated engine 10 is an engine in which fuel is injected into a combustion chamber 32, but the present invention is not limited to this, and the fuel injection device 13 according to an embodiment of the present invention may be applied to an engine in which fuel is injected into an intake port 33.

[0038] Furthermore, the engine 10 shown in the drawings is an engine mounted on a vehicle 11, but is not limited to this, and the fuel injection device 13 according to an embodiment of the present invention may be applied to an engine used as a power source for other devices, etc. Furthermore, the engine to which the fuel injection device 13 according to an embodiment of the present invention is applied may be an engine in which fuel is injected multiple times from the compression stroke to the combustion stroke, or an engine in which fuel is injected only once from the compression stroke to the combustion stroke.

[0039] In the above description, the valve seat 65 is formed using an insulating material, but this is not limited to this. For example, the valve seat 65 may be formed using a metal material, and an insulating coating treatment may be performed to form an insulating coating on the valve seat 65. In addition, in the above description, a mesh-shaped tip electrode 72 formed using a wire mesh or the like is used, but this is not limited to this, and tip electrodes of other shapes may be used. In addition, in the above description, annular flow path electrodes 71, 111 are used, but this is not limited to this, and flow path electrodes of other shapes may be used. [Explanation of symbols]

[0040] 10 Engine 13 Fuel injection device 37 Injector 50 Main body 51 Nozzle section 52 fuel flow path 63 Needle valve (valve body) 66 Injection hole 71 Flow path electrode (first electrode) 72 Tip electrode (second electrode) 73 Fuel chamber (fuel flow path) 80 Control System 81 Power supply unit (power circuit section) 100 processors 101 Main memory (memory) 110 Injector 111 Flow path electrode (first electrode) Fi internal fuel Fo external fuel

Claims

1. A fuel injection device provided in an engine, an injector including a nozzle portion in which an injection hole for injecting fuel is formed, and a main body portion in which a fuel flow path for supplying fuel to the injection hole is formed; a first electrode provided in the injector for charging an internal fuel that is the fuel in the fuel flow path; a second electrode provided in the injector for charging an external fuel that is the fuel adhering to the tip of the nozzle portion; a power supply circuit section electrically connected to the first electrode and the second electrode and applying a voltage to the first electrode and the second electrode; a control system including a processor and a memory communicably connected to each other, the control system controlling the power supply circuit unit; and The injector includes a valve body that moves between a closed position that closes the injection hole and an open position that opens the injection hole, the control system applies a voltage to the first electrode and the second electrode while the valve body is moved to the closed position, thereby charging the internal fuel and the external fuel with opposite polarities. Fuel injection device.

2. 2. The fuel injection device according to claim 1, the power supply circuit unit is controlled to an operating state in which a voltage is applied to the first electrode and the second electrode, and a stopped state in which the application of the voltage to the first electrode and the second electrode is stopped, the control system controls the power supply circuit unit to the operating state and then controls the power supply circuit unit to the stopped state while the valve body is moved to the closed position. Fuel injection device.

3. 2. The fuel injection device according to claim 1, The power supply circuit unit includes: a first operating state in which a voltage is applied to the first electrode and the second electrode, and the potential of the first electrode is made higher than the potential of the second electrode; a second operating state in which a voltage is applied to the first electrode and the second electrode, and the potential of the second electrode is increased above the potential of the first electrode; a stop state in which the voltage application to the first electrode and the second electrode is stopped; is controlled by the control system controls the power supply circuit unit to the first operating state, the stopped state, and the second operating state in this order. Fuel injection device.

4. 2. The fuel injection device according to claim 1, the first electrode is provided on the main body or the valve body, The second electrode is provided in the nozzle portion. Fuel injection device.

5. 2. The fuel injection device according to claim 1, The second electrode is configured in a mesh shape. Fuel injection device.

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