Fuel injection valve and fuel injection valve assembly

Abstract

To supply a fuel injection valve (11) which can avoid damage of a connection part (53) even if a bending force, acting in a direction of the fuel injection valve, is applied to the connection part (53) connected to a low pressure fuel pipe (60).SOLUTION: A fuel injection valve (11) is provided with a restriction part (40) which restricts bending of a connection part (53) to the side of a fuel injection hole (19) in a state that a connector (50) connected to a low pressure fuel pipe (60) is attached to a connector insertion hole (32).SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a fuel injection valve to which a connector constituting a fuel return passage can be attached, and a fuel injection valve assembly to which a connector constituting a fuel return passage is attached.

Background Art

[0002] A fuel injection valve used in a common rail system of an internal combustion engine injects fuel into the internal combustion engine by opening and closing an injection hole with a nozzle needle while high-pressure fuel pumped from a common rail is introduced into the fuel injection valve. A part of the pumped high-pressure fuel flows into a pressure control chamber of the fuel injection valve, and then a part of it is discharged from the pressure control chamber, whereby the nozzle needle retracts and the injection hole is opened. The fuel discharged from this pressure control chamber is returned to a low-pressure system such as a fuel tank via a low-pressure fuel pipe.

[0003] In such a fuel supply system, there is a configuration in which a fuel injection valve and a low-pressure fuel pipe are connected via a connector. Patent Document 1 discloses a connector for connecting this fuel injection valve and a low-pressure fuel pipe. The connector disclosed in Patent Document 1 has a first connection portion formed to extend in the axial direction for connecting to the fuel injection valve, and a second connection portion formed to extend in the radial direction to which the low-pressure fuel pipe is connected. Further, the connector is provided with a fuel passage hole inside for guiding the fuel discharged from the fuel injection valve to the low-pressure fuel pipe, and is molded from a resin material.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When a connector is molded from a resin material as disclosed in Patent Document 1, a connector that is less expensive and lighter than when using a metal material can be provided. However, there is a problem that the resin material has inferior material strength compared to the metal material. In particular, the second connection portion formed to extend in the radial direction to which the low-pressure fuel pipe is connected is an elongated tubular shape. For example, when an object or the like is mistakenly placed on its upper portion during the assembly process of an internal combustion engine, a bending force is applied to the second connection portion due to its weight. When such a mistaken handling is assumed, it is necessary to review the diameter so that the second connection portion is not damaged corresponding to the assumed bending force. For example, when the outer diameter of the second connection portion is increased, it is necessary to increase the diameter of the low-pressure fuel pipe, which is disadvantageous in terms of mountability and cost.

[0006] The present invention has been made to solve the above-described problems, and in particular, even when an object or the like is mistakenly placed on the upper portion of a connector attached to a fuel injection valve and a bending force in the fuel injection valve direction is applied to the connection portion of the connector, it is an object to provide a fuel injection valve and a fuel injection valve assembly capable of avoiding damage to the connection portion of the connector with the low-pressure fuel pipe.

Means for Solving the Problems

[0007] According to an aspect of the present invention, there is provided a fuel injection valve including a fuel injection hole for injecting fuel, a nozzle needle for opening and closing the fuel injection hole, and a pressure control chamber for forming a fuel pressure used for driving the nozzle needle, the connector having a connection portion extending in the radial direction and connected to a low-pressure fuel pipe at a rear end portion on the side opposite to the fuel injection hole, a connector insertion hole to which a connector capable of constituting a fuel return passage for returning the fuel discharged from the pressure control chamber to a fuel tank can be attached, and a restricting portion for restricting bending of the connection portion toward the fuel injection hole side when the connector connected to the low-pressure fuel pipe is attached to the connector insertion hole.

[0008] According to another aspect of the present invention, there is provided a fuel injection valve assembly including a fuel injection hole for injecting fuel, a nozzle needle for opening and closing the fuel injection hole, and a pressure control chamber for forming a fuel pressure used for driving the nozzle needle; a connector attached to a connector insertion hole provided at a rear end portion on the side opposite to the fuel injection hole, the connector constituting a fuel return passage for returning the fuel discharged from the pressure control chamber to a fuel tank; and a low-pressure fuel pipe connected to a connection portion extending radially from the connector, the fuel injection valve assembly having a restricting portion for restricting bending of the connection portion toward the fuel injection hole side.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a fuel injection valve and a fuel injection valve assembly capable of avoiding damage to the connection portion of the connector with the low-pressure fuel pipe even when an object or the like is accidentally placed on the upper part of the connector and a bending force in the direction of the fuel injection valve is applied to the connection portion of the connector.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0011] Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. However, this embodiment shows one aspect of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.

[0012] (Fuel injection system for internal combustion engine) FIG. 1 is a configuration diagram showing an example of a fuel injection system for an internal combustion engine in which a fuel injection valve and a fuel injection valve assembly according to an embodiment of the present invention are used.

[0013] The fuel injection system 1 includes a fuel tank 3, a feed pump 5, a high-pressure pump 7, a common rail 9, and a plurality of fuel injection valves 11 or fuel injection valve assemblies 12. Here, the fuel injection valve assembly 12 is obtained by attaching a connector 50 to which a low-pressure fuel pipe 60 described later is connected to the fuel injection valve 11. The fuel injection system 1 is used for an internal combustion engine such as a diesel engine or a gasoline engine.

[0014] The feed pump 5 sucks up the fuel in the fuel tank 3 and supplies it to the high-pressure pump 7. The high-pressure pump 7 pressurizes the fuel supplied from the feed pump 5 and pumps it to the common rail 9. At this time, the surplus fuel is returned to the fuel tank 3.

[0015] The common rail 9 stores the fuel pumped from the high-pressure pump 7. A plurality of fuel injection valves 11 are connected to the common rail 9, and the common rail 9 supplies high-pressure fuel to the plurality of fuel injection valves 11. As will be described later, a part of the high-pressure fuel supplied to the fuel injection valve 11 is introduced into the pressure control chamber 13. The nozzle needle 15 is urged in the direction of closing the fuel injection hole 19 by the pressure of the fuel introduced into the pressure control chamber 13. On the other hand, by discharging the fuel from the pressure control chamber 13, the nozzle needle retracts and the fuel injection hole 19 is opened. The fuel discharged from the pressure control chamber 13 is returned to the fuel tank 3 via the connector 50 and the low-pressure fuel pipe 60. In this way, the connector 50 and the low-pressure fuel pipe 60 together constitute a fuel return passage for returning the fuel discharged from the pressure control chamber to the fuel tank 3.

[0016] (Fuel injection valve) Figure 2 is a schematic diagram of a fuel injection valve and a fuel injection valve assembly according to an embodiment of the present invention. The fuel injection valve 11 includes a pressure control chamber 13, a valve piston 14, a nozzle needle 15, a fuel reservoir chamber 17, a fuel injection hole 19, a first fuel passage 21, a second fuel passage 23, a pressure control valve 25, a fuel discharge passage 28, and a rear end portion 30. Further, a connector insertion hole 32 is provided in the rear end portion 30.

[0017] A part of the high-pressure fuel supplied to the fuel injection valve 11 is introduced into the pressure control chamber 13 through the first fuel passage 21, and another part is introduced into the fuel reservoir chamber 17 through the second fuel passage 23. The pressure of the fuel in the pressure control chamber 13 acts on the rear end face of the nozzle needle 15 via the valve piston 14, and biases the nozzle needle 15 in the valve closing direction. The pressure control valve 25 is an electronically controllable solenoid valve. When the pressure control valve 25 is energized, an electromagnetic force is generated, and the armature 24 is attracted in the direction of the pressure control valve 25, and the valve portion 27 formed above the pressure control chamber 13 opens. Conversely, when the energization of the pressure control valve 25 is cut off, the armature 24 is returned in the direction of the valve portion 27 by a spring built in the pressure control valve 25, and the valve portion 27 closes.

[0018] As described above, when the pressure control valve 25 is energized with the valve portion 27 closed, the valve portion 27 opens. As a result, the high-pressure fuel in the pressure control chamber 13 passes through the valve portion 27 and is discharged, and the pressure of the fuel in the pressure control chamber 13 decreases. As the biasing force from the pressure control chamber 13 decreases, the nozzle needle 15 moves in the valve opening direction. As a result, the fuel introduced into the fuel reservoir chamber 17 is injected from the fuel injection hole 19. On the other hand, the fuel discharged from the pressure control chamber 13 passes through the fuel discharge passage 28 and is guided to the connector insertion hole 32 provided in the rear end portion 30 of the fuel injection valve 11. The connector insertion hole 32 is formed in the axial direction of the fuel injection valve 11 from the end face of the rear end portion 30 toward the fuel injection hole 19 side.

[0019] (Connection part of the connector) Next, the connection part between the fuel injection valve 11 and the connector 50 according to the present embodiment or the connection part of the connector 50 in the fuel injection valve assembly 12 will be described in detail. Figure 3 is an enlarged view of part A in Figure 2.

[0020] As shown in FIG. 3, the connector 50 is inserted into the connector insertion hole 32. After the connector 50 is inserted into the connector insertion hole 32, it is fixed to the fuel injection valve 11 by a locking mechanism not described in the figure.

[0021] The connector 50 has a connector shaft portion 51 that is inserted into the connector insertion hole 32, and one or two tubular connection portions 53 that extend in the radial direction, that is, in a direction perpendicular to the connector shaft portion 51.

[0022] A seal groove portion 52 to which a seal member 70 is attached is provided on the outer peripheral portion of the connector shaft portion 51. The seal member 70 seals between the inner peripheral surface of the connector insertion hole 32 and the outer peripheral portion of the connector shaft portion 51. The seal member 70 is, for example, an O-ring.

[0023] A truncated cone-shaped retaining portion 54 with an outer diameter that expands from the tip toward the connector shaft portion 51 side is provided on the tip side of the connection portion 53. The diameter of the retaining portion 54 is the maximum diameter at the end portion 54a on the connector shaft portion 51 side, and this diameter is formed to be larger than the inner diameter of the low-pressure fuel pipe 60. The retaining portion 54 has a function of preventing the low-pressure fuel pipe 60 connected to the connection portion 53 from coming off.

[0024] A first opening 51b is provided at the bottom portion 51a which is the axial end of the connector shaft portion 51, and a second opening 53a is provided at the tip of the connection portion 53. Inside the connector 50, a fuel passage hole 56 is formed so as to communicate the first opening 51b and the second opening 53a. The fuel passage hole 56 includes an axial hole that extends axially inside the connector shaft portion 53 from the first opening 51b, and a radial hole that extends inside the connection portion 53 from the second opening 53a and communicates with the axial hole. The fuel discharged from the pressure control chamber 13 and guided to the connector insertion hole 32 enters from the first opening 51b, passes through the fuel passage hole 56, exits from the second opening 53a, and flows into the low-pressure fuel pipe 60.

[0025] The connector 50 is a resin molded product molded from a resin such as PA (polyamide), PPS (polyphenylene sulfide), PPA (polyphthalamide), PBT (polybutylene terephthalate), or the like.

[0026] The low-pressure fuel pipe 60 is a so-called rubber hose molded from, for example, a fluorine-based rubber or the like.

[0027] In an example of assembly in a vehicle, after the fuel injection valve 11 is attached to the internal combustion engine, the connector 50 connected to the low-pressure fuel pipe 60 is assembled to the fuel injection valve 11. Incidentally, after the connector 50 is inserted into the connector insertion hole 32, the lock mechanism is set to the locked state, and the connector 50 is fixed so as not to fall off from the fuel injection valve 11.

[0028] A restricting portion 40 is further provided at the rear end portion 30 of the fuel injection valve 11 included in the fuel injection valve 11 and the fuel injection valve assembly 12 according to the present embodiment. The restricting portion 40 has a function of restricting bending of the connecting portion 53 toward the fuel injection hole 19 side in a state where the connector 50 connected to the low-pressure fuel pipe 60 is attached to the connector insertion hole 32.

[0029] As shown in FIG. 3, the restricting portion 40 is provided on the lower side in the axial direction of the connecting portion 53. When a force F1 toward the fuel injection hole 19 side is applied to the connecting portion 53 connected to the low-pressure fuel pipe 60, the connecting portion 53 is bent toward the fuel injection hole 19 side. At this time, since the outer peripheral portion of the low-pressure fuel pipe 60 that encloses the connecting portion 53 comes into contact with the restricting portion 40, bending of the connecting portion 53 toward the fuel injection hole 19 side is restricted, and damage to the connecting portion 53 can be prevented. Here, the case where the force F1 is applied is a case where an object or the like is mistakenly placed above the connecting portion 53 in the assembly process of the internal combustion engine.

[0030] Further, it is preferable that the restricting portion 40 is provided on the lower side in the axial direction of the locking portion 54. Since the locking portion 54 is provided on the tip side of the connecting portion 53, when bending is applied to the connecting portion 53, the amount of bending of the connecting portion 53 can be suppressed to be small.

[0031] Furthermore, as shown in FIG. 4, the restricting portion 40 may have an inclined portion 41 formed with an inclination angle φ in the radial direction such that the gap between the restricting portion 40 and the low-pressure fuel pipe 60 enclosing the accumulating portion 54 is within a predetermined range. The inclination angle φ of the inclined portion 41 is an inclination angle formed so as to move away from the fuel injection hole 19 toward the outer side in the radial direction. When bending is applied to the connecting portion 53, the contact range between the restricting portion 40 and the low-pressure fuel pipe 60 becomes wider, and the amount of bending can be suppressed to a small value. The inclined portion 41 may be provided on the lower side in the axial direction of the entire range L in the longitudinal direction of the accumulating portion 54, or may be provided on the lower side in the axial direction of a partial range in the longitudinal direction of the accumulating portion 54. In addition, the distance between the outer peripheral portion of the low-pressure fuel pipe 60 that comes into contact with the restricting portion 40 when bending is applied to the connecting portion 53 and the restricting portion 40 is preferably greater than 0 mm and less than or equal to 0.5 mm.

[0032] FIG. 5 is a cross-sectional view taken along line B-B in FIG. 3. The cross-section taken along line B-B is a cross-section obtained by cutting perpendicularly to the longitudinal direction of the connecting portion 53 and includes the accumulating portion 54. FIG. 5 shows an example of the restricting portion 40 having an arc portion 42 formed in an arc shape along the outer diameter of the low-pressure fuel pipe 60 enclosing the connecting portion 53. Since the restricting portion 40 has the arc portion 42, the restricting portion 40 can suppress the bending of the connecting portion 53 even when an oblique force F2 (see FIG. 5) acts on the connecting portion 53. The central angle θ of the formed arc is preferably in the range of 30 degrees or more and 180 degrees or less. Further, the arc portion 42 may be formed with an inclination angle φ in the radial direction such that the gap between the arc portion 42 and the low-pressure fuel pipe 60 enclosing the accumulating portion 54 is within a predetermined range (see FIG. 4). The inclination angle φ is an inclination angle formed so that the arc portion 41 moves away from the fuel injection hole 19 toward the outer side in the radial direction. The inclination angle φ of the arc portion 41 may be provided on the lower side in the axial direction of the entire range L in the longitudinal direction of the accumulating portion 54 (see FIG. 4), or may be provided on the lower side in the axial direction of a partial range in the longitudinal direction of the accumulating portion 54.

[0033] As described above, in the fuel injection valve 11 and the fuel injection valve assembly 12 according to the present embodiment, the restricting portion 40 that restricts the bending of the connecting portion 53 of the connector 50 toward the fuel injection hole 19 is provided at the rear end portion 30 on the side opposite to the fuel injection hole 19. Therefore, the bending of the connecting portion 53 toward the fuel injection hole 19 is restricted by the restricting portion 40. In particular, even if an object is accidentally placed above the connecting portion 53 during the assembly process of the internal combustion engine and an external force is applied, the bending of the connecting portion 53 toward the fuel injection hole 19 is restricted by the restricting portion 40, and it is possible to avoid damage to the connecting portion 53.

Explanation of Reference Numerals

[0034] 1 Fuel injection system, 3 Fuel tank, 5 Feed pump, 7 High-pressure pump, 9 Common rail, 11 Fuel injection valve, 12 Fuel injection valve assembly, 13 Pressure control chamber, 14 Valve piston, 15 Nozzle needle, 17 Fuel reservoir chamber, 19 Fuel injection hole, 21 First fuel passage, 23 Second fuel passage, 24 Amateur, 25 Pressure control valve, 27 Valve portion, 28 Fuel discharge passage, 30 Rear end portion, 32 Connector insertion hole, 40 Restricting portion, 41 Inclined portion, 42 Arc portion, 50 Connector, 51 Connector shaft portion, 51a Bottom portion, 51b First opening, 52 Seal groove portion, 53 Connecting portion, 53a Second opening, 54 Retaining portion, 54a End portion, 55 Arm portion, 56 Fuel passage hole, 57 Retaining portion, 60 Low-pressure fuel pipe, 70 Sealing member.

Claims

1. A fuel injection hole (19) for injecting fuel, a nozzle needle (15) for opening and closing the fuel injection hole (19), a pressure control chamber (13) for forming a fuel pressure used for driving the nozzle needle (15), and at a rear end portion (30) on the side opposite to the fuel injection hole (19), a connector (50) having a connector shaft portion (51) and a connection portion (53) that extends in a radial direction with respect to the axial direction of the connector shaft portion (51) and to which a low-pressure fuel pipe (60) is connected, the connector (50) being attachable to a connector insertion hole (32) that forms a fuel return passage for returning the fuel discharged from the pressure control chamber (13) to a fuel tank (3), a limiting portion (40) for restricting bending of the connection portion (53) toward the fuel injection hole (19) side in a state where the connector (50) connected to the low-pressure fuel pipe (60) is attached to the connector insertion hole (32), is provided, the connection portion (53) has a retaining portion (54) for preventing the low-pressure fuel pipe (60) from coming off, the limiting portion (40) has an arc portion (42) formed in an arc shape along the outer peripheral shape of the low-pressure fuel pipe (60), and is provided on the lower side in the direction along the axial direction of the connection portion (53), the arc portion (42) is formed with a tilt angle in the radial direction so that the gap between the arc portion (42) and the low-pressure fuel pipe (60) is within a predetermined range fuel injection valve (11).

2. A fuel injection valve (11) having a fuel injection hole (19) for injecting fuel, a nozzle needle (15) for opening and closing the fuel injection hole (19), and a pressure control chamber (13) for forming a fuel pressure used for driving the nozzle needle (15), attached to a connector insertion hole (32) provided at a rear end portion (30) on the side opposite to the fuel injection hole (19), having a connector shaft portion (51) and a connection portion (53) that extends in a radial direction with respect to the axial direction of the connector shaft portion (51) and to which a low-pressure fuel pipe (60) is connected, the connector forming a fuel return passage for returning the fuel discharged from the pressure control chamber (13) to a fuel tank (3), the low-pressure fuel pipe (60) connected to the connection portion (53), and a fuel injection valve assembly (12), having a limiting portion (40) for restricting bending of the connection portion (53) toward the fuel injection hole (19) side, the connection portion (53) has a retaining portion (54) for preventing the low-pressure fuel pipe (60) from coming off, The restricting portion (40) has an arc portion (42) formed in an arc shape along the outer peripheral shape of the low-pressure fuel pipe (60), and is provided below the connecting portion (53) in the direction along the axial direction. The arc portion (42) is formed with an inclination angle in the radial direction so that the gap between the arc portion (42) and the low-pressure fuel pipe (60) is within a predetermined range. Fuel injection valve assembly (12).

3. A fuel injection hole (19) for injecting fuel, A nozzle needle (15) for opening and closing the fuel injection hole (19), A pressure control chamber (13) for forming a fuel pressure used for driving the nozzle needle (15), Comprising: At the rear end portion (30) on the side opposite to the fuel injection hole (19), A connector (50) having a connector shaft portion (51) and a connecting portion (53) that extends in the radial direction with respect to the axial direction of the connector shaft portion (51) and to which a low-pressure fuel pipe (60) is connected, and a connector insertion hole (32) capable of attaching the connector (50) that constitutes a fuel return passage for returning the fuel discharged from the pressure control chamber (13) to the fuel tank (3). A restricting portion (40) for restricting bending of the connecting portion (53) toward the fuel injection hole (19) in a state where the connector (50) connected to the low-pressure fuel pipe (60) is attached to the connector insertion hole (32). Is provided. The restricting portion (40) has an arc portion (41) formed in an arc shape along the outer peripheral shape of the low-pressure fuel pipe (60), and is provided below the connecting portion (53) in the direction along the axial direction. A part of the low-pressure fuel pipe (60) is disposed within the arc portion (41) and is located below the position of the upper end of the arc portion (41) in the axial direction. Fuel injection valve (11).

4. The connecting portion (53) has a retaining portion (54) for preventing the low-pressure fuel pipe (60) from coming off. The restricting portion (40) is provided below the retaining portion (54) in the direction along the axial direction. The fuel injection valve (11) according to claim 3.

5. A fuel injection valve (11) having a fuel injection hole (19) for injecting fuel, a nozzle needle (15) for opening and closing the fuel injection hole (19), and a pressure control chamber (13) for forming a fuel pressure used for driving the nozzle needle (15). It is attached to a connector insertion hole (32) provided at the rear end portion (30) on the side opposite to the fuel injection hole (19), and has a connector shaft portion (51) and a connection portion (53) that extends in a radial direction with respect to the axial direction of the connector shaft portion (51) and to which a low-pressure fuel pipe (60) is connected, and a connector that constitutes a fuel return passage for returning the fuel discharged from the pressure control chamber (13) to the fuel tank (3), a low-pressure fuel pipe (60) connected to the connection portion (53), comprising a fuel injection valve assembly (12), having a limiting portion (40) that limits bending of the connection portion (53) toward the fuel injection hole (19) side, the limiting portion (40) has an arc portion (41) formed in an arc shape along the outer peripheral shape of the low-pressure fuel pipe (60), and is provided below the connection portion (53) in the direction along the axial direction, a part of the low-pressure fuel pipe (60) is disposed within the arc portion (41) and is located below the position of the upper end of the arc portion (41) in the axial direction fuel injection valve assembly (12).

6. The connection portion (53) has a retaining portion (54) for preventing the low-pressure fuel pipe (60) from coming off, the limiting portion (40) is provided below the retaining portion (54) in the direction along the axial direction The fuel injection valve assembly (12) according to claim 5.

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