JP2006194132A - Injector, fuel injection system and fluid distribution structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injector which can employ an impact wrench in order to tighten a nut and which can reduce the number of assembling steps, and to provide a fuel injection system. <P>SOLUTION: In the injector (2), a fuel case (7) is mounted on the proximal end side of an fuel inlet (5) having an axially-extending fuel passage (6), the fuel case (7) being tightened by a nut (8) screwedly engaged with a top of the fuel inlet (5). The injector (2) includes a radially-extending fuel path (10) having an opening (10a) in an outer peripheral wall of the fuel inlet (5) on which the fuel case (7) is mounted. The injector also includes a fuel supply hole (14) formed in the side wall so as to supply fuel into the fuel case (7), and a fuel pipe (3) joined to the fuel case (7) in such a manner that the fuel pipe does not interfere with the nut (8). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an injector for injecting fuel into an engine cylinder, a fuel injection system, and a fluid distribution structure for distributing fluid to a plurality of locations.

  2. Description of the Related Art Conventionally, an injector for injecting fuel into an engine cylinder generally has a structure in which a fuel pipe is connected using a cap nut. Such a structure will be described with reference to FIG. That is, the fuel pipe connection structure 100 is configured such that the end portion 102a of the fuel pipe 102 is brought into contact with the end portion of the pipe holder 101 and the both are connected by the cap nut 103 through which the fuel pipe 102 is inserted. . For example, Patent Document 1 discloses a fuel pipe connection structure of a fuel injection device. In this fuel pipe connection structure, a cap nut is also used to connect a fuel pipe and a pipe holder. The configuration is almost the same as that shown in FIG.

  FIG. 8 is a schematic configuration diagram of a fuel injection system 105 for a four-cylinder engine using a common rail 106. The fuel pipe connection structure 100 as described above can also be used for such a fuel injection system 105. . The fuel injection system 105 first supplies the fuel in the tank 107 to the common rail 106 through the first fuel pipe 109 by the high-pressure pump 108. Thereafter, from the common rail 106 to the first injector 111 through the second fuel pipe 110, to the second injector 113 through the third fuel pipe 112, to the third injector 115 through the fourth fuel pipe 114, and through the fifth fuel pipe 116 to the fourth injector. The fuel is supplied to 117. Here, since the fuel pipe 110 or the like that transfers high-pressure fuel from the common rail 106 cannot absorb pressure fluctuation due to injection by itself, the high-pressure fuel is transferred from the common rail 106 to the injectors 111, 113, 115, and 117. The fuel pipes 110, 112, 114, and 116 have the same length.

JP-A-5-172018

  However, the fuel pipe connection structure 100 as described above allows a tool, such as a spanner, for tightening the cap nut 103 from the side when the pipe holder 101 and the fuel pipe 102 are connected by the cap nut 103. Have to work. That is, it is impossible to work by using an automatic tool such as an impact wrench from the upper side of the cap nut 103. This is because the fuel pipe 102 and the tool interfere with each other.

  Further, in the fuel injection system 105 shown in FIG. 8, since the cap nuts 103 are used at both ends of the first fuel pipe 109 and the like, there are a total of 10 joints, and the number of assembly steps increases. Moreover, since the automatic tool such as an impact wrench cannot be used for tightening the cap nut 103 at each joint location, there has been a problem that a great amount of assembly labor and work time are required.

  Therefore, the present invention provides an injector, a fuel injection system, and a fluid distribution structure capable of easily tightening a nut and reducing the number of pipes, and thereby reducing the number of assembling processes of the pipes. Is an issue.

  In order to achieve the above object, an injector according to the present invention is configured such that a fuel case is crowned on the base end side of a fuel inlet having an axial fuel passage, and the fuel case is tightened with a nut that is screwed onto the top of the fuel inlet. In the injector, a radial fuel flow path having an opening in an outer peripheral wall that leads to the fuel case of the fuel inlet, and a fuel supply hole that supplies fuel into the fuel case in the side wall. And a fuel pipe joined to the fuel case so as not to interfere with the nut (claim 1). Thus, an automatic tool such as an impact wrench can be used for tightening the nut by adopting a configuration in which the fuel case is joined so as not to interfere with the nut.

  Further, by preparing a plurality of such injectors and connecting them with a single fuel pipe to form a fuel injection system (claim 8), the number of pipes in the fuel injection system can be reduced.

  The injector as described above may have a configuration in which seal members are mounted above and below the opening of the radial fuel passage (claim 2). By adopting such a configuration, it is expected to cope with pressure fluctuation when the fuel case is filled with high-pressure fuel due to the elasticity of the seal member, and the common rail itself can be eliminated. If the common rail can be eliminated, the fuel injection system can be further reduced in cost and size.

  Further, the injector as described above may be configured such that a space for filling fuel is provided in the fuel case and the seal member is accommodated in the space. With such a configuration, the pressure of the fuel filled in the fuel case is canceled out in the fuel case, and the force acting in the axial direction of the fuel inlet that is tightened with the nut can be relaxed.

  Further, in the injector as described above, the fuel case is provided with a fuel discharge hole that opens in an inner peripheral wall and a through hole that communicates with the fuel discharge hole, and the fuel pipe is inserted into the through hole so that the fuel supply hole is formed. In addition, fuel can be supplied to the fuel case through the fuel discharge hole. With this configuration, the fuel pipe and the fuel case can be joined by welding or the like to the outer peripheral surface of the fuel pipe and the periphery of the through hole provided in the fuel case. With such a joining method, the pressure of the high-pressure fuel is handled by the fuel pipe itself, and the force applied to the joined portion can be relaxed, and high reliability can be ensured.

  Further, the fuel pipe may be configured such that a portion provided with the fuel supply hole is exposed from the fuel discharge hole into the fuel case. Such a configuration eliminates the need to provide a hole after joining, and facilitates alignment of the fuel supply hole and the fuel discharge hole when the fuel pipe is passed through the insertion hole provided in the fuel case. Thus, workability can be improved.

  In the injector as described above, the cross-sectional shape of the radial fuel passage may be an oval or an oval shape with the axial direction of the fuel inlet as the longitudinal direction (Claim 6). This is to alleviate stress concentration in the radial fuel passage. From such a viewpoint, the portion along the axial direction is a straight line, and the shape of the track of the stadium is formed by connecting the upper and lower R portions with this straight line. You can also Further, if the cross-sectional diameter of the radial fuel flow path is reduced, the orifice effect can be expected.

  Further, in the injector as described above, the fuel inlet may be provided with a large-diameter portion, and the opening of the radial fuel passage may be disposed in the large-diameter portion. By adopting such a configuration, it is possible to prevent the seal member, for example, the O-ring from moving and falling off. Further, it is not necessary to provide a positioning groove for a washer to be mounted together with the O-ring. By eliminating such positioning grooves, stress concentration can be reduced. Moreover, providing the radial fuel flow path in the fuel inlet as described above leads to a decrease in the strength of the fuel inlet. However, providing the large diameter portion can also serve as reinforcement of the portion.

  Next, the fluid distribution structure of the present invention is a fluid distribution structure in which a plurality of cylindrical fluid cases are connected to one fluid pipe, and the fluid pipes are formed in through holes provided in each of the plurality of fluid cases. In addition, the fluid supply hole is provided at a position corresponding to the plurality of fluid cases on the side wall. Such a fluid distribution structure can be used for transfer and distribution of various fluids other than fuel. The fluid case and the fluid pipe in the present invention correspond to the fuel case and the fuel pipe in the injector, respectively.

  According to the present invention, a radial fuel flow path that communicates with an axial fuel passage and has an opening in an outer peripheral wall on which the fuel case of the fuel inlet is crowned, and a fuel supply that supplies fuel into the fuel case on the side wall Since the injector has a hole and a fuel pipe joined to the fuel fuel case so as not to interfere with the nut, the nut can be tightened from above the nut using an automatic tool such as an impact wrench.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view illustrating a schematic configuration of a fuel injection system 1 according to a first embodiment. This fuel injection system 1 is for a four-cylinder engine, and includes four injectors 2, and these four injectors 2 are connected to one fuel pipe 3. The fuel pipe 3 is connected to a fuel pump 4 serving as a fuel supply means for the fuel pipe 3.

  As shown in FIG. 2, each injector 2 has a fuel case 7 on the base end side of a fuel inlet 5 having an axial fuel passage 6, and a nut for screwing the fuel case 7 onto the top of the fuel inlet 5. 8 is tightened.

  2, the fuel inlet 5 is provided with a radial fuel flow path 10 that communicates with the axial fuel passage 6 in a portion surrounded by a dashed ellipse 9 and has an opening 10a on the outer peripheral wall. FIG. 3 is an enlarged view of a portion surrounded by an ellipse 9 in FIG. 2, but the radial fuel flow path 10 intersects the radial direction in a cross shape. The cross-sectional shape of the radial fuel passage 10 is an oval having the axial direction of the fuel inlet 5 as a longitudinal direction. This is a measure for stress relaxation of the part.

  A portion having such a radial fuel flow path 10 is formed with a large diameter portion 5a having a diameter larger than that of other portions, and the opening 10a is disposed in the large diameter portion 5a. By providing such a large diameter portion, the strength of the portion is ensured.

  O-rings 11 as seal members are mounted on the upper and lower sides of the large-diameter portion 5a. A backup ring 12 is mounted so as to sandwich each O-ring 11. Further, a washer 13 is attached to the lower side of the upper O-ring 11. Here, since the O-ring 11 has elasticity, when the O-ring 11 is attached to the lower side of the large-diameter portion 5a, the O-ring is pushed and widened to get over the large-diameter portion 5a. Since each backup ring 12 is a C-shaped ring, it is mounted from the side of the fuel inlet 5. The washer 13 has an inner diameter smaller than that of the large diameter portion 5a. By attaching the washer 13, it is possible to prevent the upper O-ring 11 from moving when the fuel case 7 is attached to the fuel inlet 5.

  The fuel inlet 5 has a shape in which a shoulder portion 5 b is formed, and a space filled with fuel is formed between the fuel inlet 5 and the fuel case 7 when the fuel case 7 is covered.

  The fuel case 7 is provided with a fuel discharge hole 14 opened in the inner peripheral wall and a through hole 15 communicating with the fuel discharge hole 14. The fuel pipe 3 is caused to pass through the through hole 15. Here, the fuel pipe 3 is provided with four fuel supply holes 16 on the side wall thereof. When joining the fuel case 7 and the fuel pipe 3, the portion provided with the fuel supply hole 16 is exposed to the inside of each fuel case 7 from the fuel discharge hole 14 provided in each fuel case 7 for brazing and joining. To do. This brazing joining is performed at the position indicated by reference numeral 17 in FIG. 4, that is, at the outer peripheral surface of the fuel pipe 3. By adopting such a joining method, the pressure of the high-pressure fuel flowing through the fuel pipe 3 can be substantially handled by the fuel pipe 3 itself. The fuel supply hole 16 and the fuel discharge hole 14 may be formed from the inside of the fuel case 7 after joining the fuel case 7 and the fuel pipe 3.

  Each fuel case 7 joined to the fuel pipe 3 in this manner is attached by covering the base end side of the fuel inlet 5 and tightening the nut 8.

  In the fuel injection system 1 of the present embodiment, the fuel pipe is also attached to the fuel pump 4 using the same fuel case 7 a as that attached to the fuel inlet 5.

  Here, in the fuel injection system 1 of the present embodiment, each fuel case 7 is once filled with high-pressure fuel and then injected into the engine cylinder. However, the elasticity of the O-ring 11 attached to the fuel inlet 5 is used. As a result, the pulsation of the fuel can be alleviated, so that the common rail can be eliminated.

  In the fuel injection system 1 having such a configuration, it is only necessary to tighten the nuts 8 at five locations. Compared to the nut tightening locations 10 in the fuel injection system 105 using the conventional common rail 106 shown in FIG. A significant reduction in assembly man-hours has been achieved. Moreover, since the nut can be clamped from the upper side of the nut 8 in any of the tightening of the five nuts 8, the work with the impact wrench can be performed, and the work efficiency can be greatly improved.

  When such a fuel injection system 1 is actually assembled to an engine, the fuel pipe 3 and the fuel case 7 are joined and integrated, and the main body portion (the fuel inlet 5 side) of the injector 2 assembled to the engine head. Each case is covered with a fuel case 7 and tightened with a nut 8.

  Next, a second embodiment of the present invention will be described. FIG. 5 is a partially enlarged explanatory view of the injector 20 of the second embodiment, but differs from the injector 2 of the first embodiment shown in FIG. 2 in the following points. In the injector 2 of the first embodiment, the shoulder 5 b is provided in the fuel inlet 5, and the O-ring 11 is attached to the fuel inlet 5, and high-pressure fuel is supplied and filled between the fuel inlet 5 and the fuel case 7. It is the composition which becomes. In contrast, in the injector 20 of the second embodiment, the outer wall of the fuel inlet 21 has a substantially straight shape, and a space 22a is provided on the inner peripheral side of one fuel case 22, and a seal is provided in the space 22a. The O-ring 11 as a member is accommodated.

  In the injector 20 having such a structure, the space 22a is filled with high-pressure fuel. The force due to the pressure of the high-pressure fuel in the fuel case 22 is as shown by arrows A and B. Since it cancels out in the inside 22, the stress which arises in the fuel inlet 21 can be relieved.

  In addition, about the component same as the injector 2 in Example 1, the same reference number is attached | subjected in drawing and the detailed description is abbreviate | omitted.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited to them. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

For example, as shown in FIG. 6, it is also possible to provide a recess in the fuel inlet 25 to form a space 26 between the fuel case 7 and store the O-ring 11 in the space 26. In this case, since accommodation of the O-ring 11 is difficult, the fuel inlet 25 is divided into two parts, an upper member 25a and a lower member 25b. 25 can be formed.
Further, the structure and sealing method used in the present invention can be used not only in a fuel injection system such as an injector but also in other general fluid pipe connections.

1 is a perspective view illustrating a schematic configuration of a fuel injection system according to Embodiment 1. FIG. It is explanatory drawing which shows the structure of the injector of Example 1. FIG. FIG. 3 is an enlarged view of a portion surrounded by a dashed ellipse in FIG. 2. It is explanatory drawing which looked at the injector shown in FIG. 2 from the upper side. It is a partially expanded explanatory view of the injector of Example 2. It is a partially expanded explanatory view of the injector of another Example. It is explanatory drawing which made the conventional fuel pipe connection structure the cross section. It is a schematic block diagram of the conventional fuel injection system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection system 2, 20 Injector 3 Fuel pipe 4 Fuel pump 5, 21, 25 Fuel inlet 5a Large diameter part 6 Axial fuel flow path 7, 22 Fuel case 8 Nut 10 Radial fuel flow path 10a Opening 11 O-ring 12 Back-up ring 13 Washer 14 Fuel injection hole 15 Insertion hole 16 Fuel supply hole

Claims (9)

In an injector in which a fuel case is crowned on the base end side of a fuel inlet having an axial fuel passage, and the fuel case is tightened by a nut screwed onto a top portion of the fuel inlet.
A radial fuel flow path that communicates with the axial fuel passage and has an opening in an outer peripheral wall on which the fuel case of the fuel inlet is crowned;
A fuel pipe provided in the side wall with a fuel supply hole for supplying fuel into the fuel case and joined to the fuel case so as not to interfere with the nut; and
Injector characterized by having. The injector according to claim 1, wherein
An injector having a seal member mounted above and below the opening of the radial fuel passage. Injector according to claim 2,
An injector characterized in that a space for filling fuel is provided in the fuel case, and the seal member is housed in the space. The injector according to any one of claims 1 to 3,
The fuel case is provided with a fuel discharge hole that opens in an inner peripheral wall and a through hole that communicates with the fuel discharge hole. The fuel pipe is inserted into the through hole, and the fuel case is inserted into the fuel case through the fuel supply hole and the fuel discharge hole. An injector characterized by supplying fuel. Injector according to claim 4,
The injector, wherein the fuel pipe has a portion provided with the fuel supply hole exposed from the fuel discharge hole into the fuel case. The injector according to any one of claims 1 to 5,
An injector characterized in that a cross-sectional shape of the radial fuel passage is an oval or an oval with the axial direction of the fuel inlet as a longitudinal direction. The injector according to any one of claims 1 to 6,
The fuel inlet is provided with a large-diameter portion, and the opening of the radial fuel passage is disposed in the large-diameter portion. A plurality of injectors according to any one of claims 1 to 7;
And a fuel supply unit for the fuel pipe, wherein the fuel pipe is a single fuel pipe. A fluid distribution structure in which a plurality of cylindrical fluid cases are connected to one fluid pipe,
The fluid distribution structure according to claim 1, wherein the fluid pipe is inserted into a through hole provided in each of the plurality of fluid cases, and a fluid supply hole is provided at a position corresponding to the plurality of fluid cases on the side wall.

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