JP7705233B2 - Fuel injection valve and fuel injection valve assembly - Google Patents

Description

The present invention relates to a fuel injection valve to which a connector that forms a fuel return passage can be attached, and a fuel injection valve assembly to which a connector that forms a fuel return passage is attached.

A fuel injection valve used in an internal combustion engine's common rail system injects fuel into the internal combustion engine by opening and closing the injection hole with a nozzle needle while high-pressure fuel pumped from the common rail is introduced into the fuel injection valve. Some of the pumped high-pressure fuel flows into the pressure control chamber of the fuel injection valve and then some of it is released from the pressure control chamber, causing the nozzle needle to retract and open the injection hole. The fuel released from the pressure control chamber is returned to the low-pressure system, such as the fuel tank, via a low-pressure fuel pipe.

In such fuel supply systems, there are those that are configured to connect the fuel injection valve and the low-pressure fuel pipe via a connector. Patent Document 1 discloses a connector that connects this fuel injection valve and the low-pressure fuel pipe. The connector disclosed in Patent Document 1 has a first connection part formed to extend in the axial direction and connected to the fuel injection valve, and a second connection part formed to extend in the radial direction and connected to the low-pressure fuel pipe. In addition, the connector is formed with a fuel passage hole inside that guides fuel discharged from the fuel injection valve to the low-pressure fuel pipe, and is molded from a resin material.

JP 2010-236645 A

When a connector is molded from a resin material as disclosed in Patent Document 1, a connector that is cheaper and lighter than a connector made from a metal material can be provided. However, there is a problem that the material strength of a resin material is inferior to that of a metal material. In particular, the second connection part formed to extend in the radial direction and to which the low-pressure fuel pipe is connected is a long and thin tube, and if an object is mistakenly placed on top of the second connection part during the assembly process of the internal combustion engine, for example, a bending force is applied to the second connection part due to the weight of the object. In the event of such incorrect handling, it is necessary to review the diameter of the second connection part so that it is not damaged in response to the expected bending force. However, for example, if the outer diameter of the second connection part is increased, the diameter of the low-pressure fuel pipe must also be increased, which is disadvantageous in terms of mountability and cost.

The present invention has been made to solve the above-mentioned problems, and in particular aims to provide a fuel injection valve and a fuel injection valve assembly that can prevent damage to the connection between the connector and the low-pressure fuel pipe even if an object is mistakenly placed on top of the connector attached to the fuel injection valve and a bending force is applied to the connection part of the connector in the direction of the fuel injection valve.

According to one aspect of the present invention, there is provided a fuel injection valve comprising a fuel injection hole for injecting fuel, a nozzle needle for opening and closing the fuel injection hole, and a pressure control chamber for generating a fuel pressure used to drive the nozzle needle, and a connector having a connection part that extends radially and is connected to a low-pressure fuel pipe at a rear end opposite the fuel injection hole, a connector insertion hole into which a connector constituting a fuel return passage that returns fuel discharged from the pressure control chamber to a fuel tank is attached, and a limiting part that limits bending of the connection part toward the fuel injection hole when the connector connected to the low-pressure fuel pipe is attached to the connector insertion hole.

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 generating a fuel pressure used to drive the nozzle needle, a connector attached to a connector insertion hole provided at the rear end opposite the fuel injection hole and constituting a fuel return passage for returning fuel discharged from the pressure control chamber to a fuel tank, and a low-pressure fuel pipe connected to a connection part extending radially from the connector, the fuel injection valve assembly having a limiting part for limiting bending of the connection part toward the fuel injection hole.

The present invention provides a fuel injection valve and a fuel injection valve assembly that can prevent damage to the connection between the connector and the low-pressure fuel pipe, even if an object is mistakenly placed on top of the connector and a bending force is applied to the connection of the connector in the direction of the fuel injection valve.

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; 1 is a schematic diagram of a fuel injector and a fuel injector assembly according to an embodiment of the present invention; FIG. 3 is an enlarged view of part A in FIG. 2 . FIG. 4 is a schematic diagram illustrating an example of a limiting portion. This is a cross-sectional view taken along the line B-B in FIG.

The following describes an embodiment of the present invention in detail with reference to the attached drawings. However, this embodiment shows one aspect of the present invention, does not limit the present invention, and can be modified as desired within the scope of the present invention.

(Fuel injection system for internal combustion engines)
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.

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 a fuel injection valve 11 to which a connector 50 to which a low-pressure fuel pipe 60 described below is attached is attached. The fuel injection system 1 is used in internal combustion engines such as diesel engines and gasoline engines.

The feed pump 5 draws 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 sends it to the common rail 9. At this time, the excess fuel is returned to the fuel tank 3.

The common rail 9 stores 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 described below, a portion of the high-pressure fuel supplied to the fuel injection valves 11 is introduced into the pressure control chamber 13. The pressure of the fuel introduced into the pressure control chamber 13 biases the nozzle needle 15 in a direction to close the fuel injection hole 19. On the other hand, by discharging 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, together with the low-pressure fuel pipe 60, constitute a fuel return passage that returns the fuel discharged from the pressure control chamber to the fuel tank 3.

(Fuel injection valve)
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. A connector insertion hole 32 is also provided in the rear end portion 30.

Part of the high-pressure fuel supplied to the fuel injection valve 11 is introduced into the pressure control chamber 13 via the first fuel passage 21, and the other part is introduced into the fuel reservoir chamber 17 via the second fuel passage 23. The pressure of the fuel in the pressure control chamber 13 acts on the rear end surface of the nozzle needle 15 via the valve piston 14, urging 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 toward the pressure control valve 25, opening the valve portion 27 formed above the pressure control chamber 13. Conversely, when the pressure control valve 25 is de-energized, the armature 24 is returned toward the valve portion 27 by a spring built into the pressure control valve 25, and the valve portion 27 is closed.

As described above, when the pressure control valve 25 is energized with the valve portion 27 closed, the valve portion 27 opens. This causes the high-pressure fuel in the pressure control chamber 13 to pass through the valve portion 27 and be discharged, lowering the pressure of the fuel in the pressure control chamber 13. 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. Meanwhile, 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.

(Connector connection part)
Next, a detailed description will be given of the connection portion between the fuel injection valve 11 and the connector 50 according to this embodiment, or the connection portion of the connector 50 in the fuel injection valve assembly 12. Fig. 3 is an enlarged view of part A in Fig. 2.

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 shown).

The connector 50 has a connector shaft 51 that is inserted into the connector insertion hole 32 and one or two cylindrical connection parts 53 that extend radially, i.e., perpendicularly to the connector shaft 51.

A seal groove 52 is provided on the outer periphery of the connector shaft 51, into which a seal member 70 is attached. The seal member 70 provides a seal between the inner periphery of the connector insertion hole 32 and the outer periphery of the connector shaft 51. The seal member 70 is, for example, an O-ring.

A truncated cone-shaped retaining portion 54 is provided at the tip side of the connection portion 53, the outer diameter of which increases from the tip toward the connector shaft portion 51. The diameter of the retaining portion 54 is maximum 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 the function of preventing the low-pressure fuel pipe 60 connected to the connection portion 53 from coming loose.

The bottom 51a, which is the axial end of the connector shaft 51, is provided with a first opening 51b, and the tip of the connection part 53 is provided with a second opening 53a. Inside the connector 50, a fuel passage hole 56 is formed to communicate between the first opening 51b and the second opening 53a. The fuel passage hole 56 has an axial hole extending axially from the first opening 51b inside the connector shaft 53, and a radial hole extending from the second opening 53a inside the connection part 53 and communicating 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 out into the low-pressure fuel pipe 60.

The connector 50 is a resin molded product made of resin such as PA (polyamide), PPS (polyphenylene sulfide), PPA (polyphthalamide), or PBT (polybutylene terephthalate).

The low-pressure fuel pipe 60 is a rubber hose made of, for example, fluorine-based rubber.

In one 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. After the connector 50 is inserted into the connector insertion hole 32, the locking mechanism is locked, and the connector 50 is fixed so that it does not fall off the fuel injection valve 11.

The rear end 30 of the fuel injection valve 11 provided in the fuel injection valve 11 and fuel injection valve assembly 12 according to this embodiment is further provided with a restriction portion 40. The restriction portion 40 has the function of restricting bending of the connection portion 53 toward the fuel injection hole 19 when the connector 50 connected to the low-pressure fuel pipe 60 is attached to the connector insertion hole 32.

As shown in FIG. 3, the restriction portion 40 is provided axially below the connection portion 53. When a force F1 toward the fuel injection hole 19 is applied to the connection portion 53 connected to the low-pressure fuel pipe 60, the connection portion 53 is bent toward the fuel injection hole 19. At this time, the outer peripheral portion of the low-pressure fuel pipe 60 containing the connection portion 53 comes into contact with the restriction portion 40, so bending of the connection portion 53 toward the fuel injection hole 19 is restricted, and damage to the connection portion 53 can be prevented. Here, the case where force F1 is applied is when an object is mistakenly placed above the connection portion 53 during the assembly process of the internal combustion engine.

In addition, it is preferable that the restricting portion 40 is provided axially below the retaining portion 54. Since the retaining 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 kept small.

Furthermore, as shown in FIG. 4, the restriction portion 40 may have an inclined portion 41 formed with an inclination angle φ in the radial direction so that the gap between the restriction portion 40 and the low-pressure fuel pipe 60 containing the retaining 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 radially outward direction. When bending is applied to the connection portion 53, the contact range between the restriction portion 40 and the low-pressure fuel pipe 60 becomes wider, and the amount of bending can be kept small. The inclined portion 41 may be provided on the axially lower side of the entire range L in the longitudinal direction of the retaining portion 54, or may be provided on the axially lower side of a part of the longitudinal range of the retaining portion 54. In addition, it is preferable that the distance between the outer periphery of the low-pressure fuel pipe 60 that contacts the restriction portion 40 when bending is applied to the connection portion 53 and the restriction portion 40 is in the range of more than 0 mm and 0.5 mm or less.

Figure 5 is a cross-sectional view taken along line B-B in Figure 3. The B-B cross section is a cross section taken perpendicularly to the longitudinal direction of the connection portion 53, and includes the retaining portion 54. Figure 5 shows an example of a restricting portion 40 having an arc portion 42 formed in an arc shape along the outer diameter of the low-pressure fuel pipe 60 containing the connection portion 53. By having the arc portion 42 in the restricting portion 40, the restricting portion 40 can suppress bending of the connection portion 53 even when an oblique force F2 (see Figure 5) acts on the connection portion 53. The central angle θ of the formed arc is preferably in the range of 30 degrees to 180 degrees. In addition, the arc portion 42 may be formed with an inclination angle φ in the radial direction so that the gap between the arc portion 42 and the low-pressure fuel pipe 60 containing the retaining portion 54 is within a predetermined range (see Figure 4). The inclination angle φ is an inclination angle formed so that the arc portion 41 moves radially outward away from the fuel injection hole 19. The inclination angle φ of the arc portion 41 may be set on the axially lower side of the entire longitudinal range L of the fastening portion 54 (see FIG. 4), or may be set on the axially lower side of a portion of the longitudinal range of the fastening portion 54.

As described above, in the fuel injection valve 11 and fuel injection valve assembly 12 according to this embodiment, the rear end portion 30 opposite the fuel injection hole 19 is provided with a limiting portion 40 that limits the bending of the connection portion 53 of the connector 50 toward the fuel injection hole 19, so that the bending of the connection portion 53 toward the fuel injection hole 19 is limited by the limiting portion 40. In particular, even if an object is mistakenly placed above the connection portion 53 during the assembly process of the internal combustion engine and an external force is applied, the bending of the connection portion 53 toward the fuel injection hole 19 is limited by the limiting portion 40, and damage to the connection portion 53 can be avoided.

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 armature, 25 pressure control valve, 27 valve portion, 28 fuel discharge passage, 30 rear end portion, 32 connector insertion hole, 40 limiting portion, 41 inclined portion, 42 arc portion, 50 connector, 51 connector shaft portion, 51a bottom portion, 51b first opening portion, 52 seal groove portion, 53 connection portion, 53a second opening portion, 54 retaining portion, 54a end portion, 55 arm portion, 56 fuel passage hole, 57 retaining portion, 60 low pressure fuel pipe, 70 seal member.

Claims (6)

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 generating a fuel pressure used to drive the nozzle needle (15);
Equipped with
At the rear end portion (30) opposite the fuel injection hole (19),
a connector (50) having a connector shaft portion (51) and a connection portion (53) extending radially with respect to an axial direction of the connector shaft portion (51) and connected to a low-pressure fuel pipe (60), the connector (50) constituting a fuel return passage that returns fuel discharged from the pressure control chamber (13) to a fuel tank (3) and a connector insertion hole (32) into which the connector (50) can be attached;
a limiting portion (40) for limiting bending of the connection portion (53) toward the fuel injection hole (19) when the connector (50) connected to the low pressure fuel pipe (60) is attached to the connector insertion hole (32);
was established,
The connection portion (53) has a retaining portion (54) that prevents 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 periphery of the low-pressure fuel pipe (60) , and is provided below the connecting portion (53) in a 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.
A fuel injection valve (11). 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 generating a fuel pressure used to drive the nozzle needle (15);
a connector that is attached to a connector insertion hole (32) provided in a rear end portion (30) on the opposite side to the fuel injection hole (19), the connector having a connector shaft portion (51) and a connection portion (53) extending radially with respect to the axial direction of the connector shaft portion (51) and connected to a low-pressure fuel pipe (60), and that constitutes a fuel return passage that returns fuel discharged from the pressure control chamber (13) to a fuel tank (3);
A low-pressure fuel pipe (60) connected to the connection portion (53).
A fuel injection valve assembly (12), comprising:
a limiting portion (40) that limits bending of the connection portion (53) toward the fuel injection hole (19),
The connection portion (53) has a retaining portion (54) that prevents 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 periphery of the low-pressure fuel pipe (60) , and is provided below the connecting portion (53) in a 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). 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 generating a fuel pressure used to drive the nozzle needle (15);
Equipped with
At the rear end portion (30) opposite the fuel injection hole (19),
a connector (50) having a connector shaft portion (51) and a connection portion (53) extending radially with respect to an axial direction of the connector shaft portion (51) and connected to a low-pressure fuel pipe (60), the connector (50) constituting a fuel return passage that returns fuel discharged from the pressure control chamber (13) to a fuel tank (3) and a connector insertion hole (32) into which the connector (50) can be attached;
a limiting portion (40) for limiting bending of the connection portion (53) toward the fuel injection hole (19) when the connector (50) connected to the low pressure fuel pipe (60) is attached to the connector insertion hole (32);
was established,
the limiting portion (40) has an arc portion (41) formed in an arc shape that follows the shape of an outer periphery of the low-pressure fuel pipe (60) , and is provided below the connection portion (53) in a direction along the axial direction,
A portion 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.
A fuel injection valve (11). The connection portion (53) has a retaining portion (54) that prevents the low-pressure fuel pipe (60) from coming off,
The limiting portion (40) is provided below the retaining portion (54) in the axial direction.
A fuel injection valve (11) according to claim 3. 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 generating a fuel pressure used to drive the nozzle needle (15);
a connector that is attached to a connector insertion hole (32) provided in a rear end portion (30) on the opposite side to the fuel injection hole (19), the connector having a connector shaft portion (51) and a connection portion (53) extending radially with respect to the axial direction of the connector shaft portion (51) and connected to a low-pressure fuel pipe (60), and that constitutes a fuel return passage that returns fuel discharged from the pressure control chamber (13) to a fuel tank (3);
A low-pressure fuel pipe (60) connected to the connection portion (53).
A fuel injection valve assembly (12), comprising:
a limiting portion (40) that limits bending of the connection portion (53) toward the fuel injection hole (19),
the limiting portion (40) has an arc portion (41) formed in an arc shape that follows the shape of an outer periphery of the low-pressure fuel pipe (60) , and is provided below the connection portion (53) in a direction along the axial direction,
A portion 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). The connection portion (53) has a retaining portion (54) that prevents the low-pressure fuel pipe (60) from coming off,
The limiting portion (40) is provided below the retaining portion (54) in the axial direction.
The fuel injection valve assembly (12) of claim 5.

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