JP5447138B2 - High-pressure fuel piping structure - Google Patents

Description

The present invention relates to a structure of the high pressure fuel pipe for supplying high pressure fuel to the injector for injecting fuel into the cylinders of the engine.

  In a vehicle such as an automobile, a direct injection engine in which fuel is directly injected into an engine cylinder by an injector is known. In an in-line direct injection engine in which a plurality of cylinders are arranged in a row, the engine cylinder A fuel rail section that extends in the column direction and is supplied with high-pressure fuel, a fuel distribution section that distributes and supplies high-pressure fuel from the fuel rail section to the injector, and a fastening boss section that is attached to the engine. A high-pressure fuel pipe is used in which the high-pressure fuel pumped to the section is distributed and supplied to the injector through the fuel distribution section.

  As this high-pressure fuel pipe, there is one in which the fuel rail part, fuel distribution part and fastening boss part are integrally formed by casting, but in recent years, as part of meeting the demand for weight reduction, the wall thickness has been reduced. It is known that the fuel rail part, the fuel distribution part, and the fastening boss part are integrally formed by casting, which is difficult to perform, but the weight is reduced by using a pipe member for the fuel rail part. Yes.

  As such a high-pressure fuel piping structure, for example, one disclosed in Patent Document 1 is known. As shown in FIG. 8, this high-pressure fuel piping 100 is a tubular fuel rail portion 101 to which high-pressure fuel is supplied. And the fuel distribution portions 102 that are joined to the fuel rail portions 101 and connected to the injectors attached to the cylinder head, respectively, and the fuel rail portions 101 adjacent to the fuel distribution portions 102 and joined to the fuel rail portions 101, respectively. When a high-pressure fuel pumped from a fuel pump is distributed and supplied to the fuel distribution section 102 through the fuel rail section 101 and the injector is opened. The fuel is injected into the cylinder through the injector.

  In the high-pressure fuel pipe 100 configured as described above, the fuel distribution portion 102 and the fastening boss portion 103 are joined to the fuel rail portion 101 by, for example, temporary attachment and brazing, but the fuel distribution portion 102 to the fuel rail portion 101 is joined. The fuel rail portion 101 is thermally deformed when the fastening boss portion 103 is joined, and when the high-pressure fuel pipe 100 is attached to the engine, the injector and the fuel distribution portion 102 are not well coupled. There is a possibility that a gap may be generated between the two and fuel leakage may occur.

  Further, since the fuel distribution portion 102 and the fastening boss portion 103 are joined to the fuel rail portion 101, variation in the mounting position between the fuel distribution portion 102 and the fuel rail portion 101, and the fastening boss portion 103 and the fuel rail portion 101, When the high-pressure fuel pipe 100 is attached to the engine due to the variation in the attachment position, the injector and the fuel distributor 102 are not well coupled, and a gap is generated between the injector and the fuel distributor, resulting in fuel leakage. There is drowning.

  On the other hand, the one described in the cited document 1 is connected to the injector accommodating portion 102a and the fastening boss portion 103 provided in the fuel distribution portion 102 after the fuel distribution portion 102 and the fastening boss portion 103 are joined to the fuel rail portion 101. By cutting and finishing the engine mounting hole 103a provided, it is possible to satisfactorily connect the injector and the fuel distributor 102 and prevent fuel leakage when attached to the engine. .

JP 2010-7651 A

  However, the high-pressure fuel pipe described in the cited document 1 requires work after the fuel distribution portion and the fastening boss portion are processed after the fuel distribution portion and the fastening boss portion are joined to the fuel rail portion. However, the manufacturing cost increases. Therefore, it is desired to suppress the occurrence of fuel leakage by satisfactorily coupling the injector and the fuel distributor when the high-pressure fuel pipe is attached to the engine without performing a processing step after joining.

  Further, when the fuel distribution part and the fastening boss part are joined to the fuel rail part, since the fuel distribution part and the fuel rail part are joined, the fuel distribution part acts on the fuel distribution part along with the fuel injection of the injector. The reaction force is transmitted to the fuel rail portion, and a torsional or bending moment acts on the fuel rail portion, which may impair the reliability of the fuel rail portion.

Therefore, the present invention can suppress the occurrence of fuel leakage when the high-pressure fuel pipe is attached to the engine, and can suppress the torsion and bending moment from acting on the fuel rail portion. an object of the present invention is to provide a structure of the fuel pipe.

For this reason, the invention according to claim 1 of the present application includes a tubular fuel rail portion that extends in the cylinder row direction of an engine in which a plurality of cylinders are arranged in a row and is supplied with high-pressure fuel, and each fuel rail portion includes A high-pressure fuel distribution section that distributes and supplies high-pressure fuel to injectors provided corresponding to the cylinders; and a fastening boss section that is attached to the engine; and a high-pressure fuel that distributes and supplies high-pressure fuel from the fuel rail section to the injector The fuel distribution structure has a distribution passage for distributing and supplying high-pressure fuel from the fuel rail portion to the injector, the fuel passage portion joined to the fuel rail portion, and the fuel the fuel passage portion and is integrally formed on the opposite side of said fuel rail portion of the passage portion, the cup portion in which the injector is accommodated, is accommodated in the cup portion A first connecting part that extends obliquely with respect to the axial direction of the injector and connects the cup part and the fastening boss part, and extends in a direction perpendicular to the axial direction of the injector accommodated in the cup part. A second connecting part that connects the cup part and the fastening boss part, and the fastening boss part is provided in the vicinity of the cup part and is formed integrally with the fuel distribution part. It is characterized by that.

  The invention according to claim 2 of the present application is the invention according to claim 1, wherein the fuel passage portion is formed to have a smaller cross-sectional area on the cup portion side than the joint portion with the fuel rail portion. It is characterized by that.

  Further, the invention according to claim 3 of the present application is the invention according to claim 1 or 2, wherein the fuel passage portion is brazed to the fuel rail portion after being temporarily attached and joined to the fuel rail portion. It is characterized by that.

  Still further, the invention according to claim 4 of the present application is the invention according to claim 3, wherein the fuel passage portion is at both end portions in a direction orthogonal to the longitudinal direction of the fuel rail portion at the joint portion with the fuel rail portion. It is characterized in that it is temporarily attached to one place.

  According to the invention of claim 1 of the present application, the fuel distribution portion has a distribution passage for distributing and supplying high-pressure fuel from the fuel rail portion to the injector, a fuel passage portion joined to the fuel rail portion, and a fuel The fuel passage portion is formed integrally with the fuel rail portion on the opposite side of the fuel rail portion of the passage portion, and includes a cup portion in which the injector is accommodated, and the fastening boss portion is provided in the vicinity of the cup portion and integrated with the fuel distribution portion. Is formed. Thereby, when attached to the engine, the fuel distribution part and the fastening boss part are integrally formed as compared with the case where the fuel distribution part and the fastening boss part are respectively attached to the fuel rail part. Suppresses the occurrence of fuel leakage due to a gap between the injector and the fuel distribution part due to a tight fit between the base end side of the injector and the cup part, and the injector and the fuel distribution part are not coupled well. Can do.

  In addition, since the fuel distribution portion and the fastening boss portion are integrally formed, the joint location to the fuel rail portion can be reduced as compared with the case where the fuel distribution portion and the fastening boss portion are respectively attached to the fuel rail portion. Since it can be reduced, the fuel rail can be prevented from being thermally deformed, and when it is attached to the engine, the fitting between the proximal end side of the injector and the cup is broken and fuel leakage occurs. Further suppression can be achieved. When thermal deformation of the fuel rail part is large, a process for machining the portion of the cup part in which the injector is accommodated after joining is necessary to ensure a good fitting state between the base end side of the injector and the cup part. However, there is no need to perform such processing, workability can be improved, and manufacturing costs can be reduced.

Furthermore, since the fuel distribution part and the fastening boss part are integrally formed, the reaction force acting on the cup part as the fuel is injected from the injector can be dispersed in the fastening boss part. It is possible to suppress the action of torsion and bending on the cylinder, and to improve the reliability of the high-pressure fuel pipe structure.
Still further, the fuel distribution portion extends inclining with respect to the axial direction of the injector accommodated in the cup portion, and includes a first connection portion that connects the cup portion and the fastening boss portion, and an injector accommodated in the cup portion. When the cup part and the fastening boss part are connected together as a whole by including a second connection part that extends in a direction perpendicular to the axial direction and connects the cup part and the fastening boss part. In comparison, the reaction force acting on the cup portion in accordance with the fuel injection of the injector can be effectively dispersed in the fastening boss portion while achieving weight reduction, and the above-described effect can be more effectively achieved.

  According to the invention of claim 2 of the present application, the fuel passage portion is formed with a smaller cross-sectional area on the cup portion side than the joint portion with the fuel rail portion. As a result, when a variation occurs in the mounting positions of the plurality of fuel distribution portions joined to the fuel rail portion, the fuel passage portion is displaced and acts to absorb this variation. Therefore, it is possible to suppress a torsional or bending moment from acting on the fuel rail portion when it is attached to the engine.

  Further, according to the invention according to claim 3 of the present application, the fuel passage portion is brazed to the fuel rail portion after provisional attachment, and is joined to the fuel rail portion, thereby realizing the effect more specifically. be able to. By performing temporary attachment when the fuel passage portion is joined to the fuel rail portion by brazing, the joining accuracy of the fuel distribution portion to the fuel rail portion can be increased, and the fuel rail portion and the fuel distribution portion are joined. Quality can be improved.

Furthermore, according to the invention according to claim 4 of the present application, the fuel passage portion is temporarily attached to both ends in the direction orthogonal to the longitudinal direction of the fuel rail portion at the joint portion with the fuel rail portion. If there is only one temporary attachment point between the fuel passage part and the fuel rail part, a gap may be generated between the joint surfaces of the fuel passage part and the fuel rail part. By setting it as 2 points | pieces, it can suppress that a clearance gap generate | occur | produces between this joining surfaces.
In addition, when the temporary attachment points are not set at both ends in the direction orthogonal to the longitudinal direction of the fuel rail portion, for example, one temporary attachment point and the other temporary attachment point are shifted in the longitudinal direction of the fuel rail portion, respectively. If there is no thermal deformation due to one tacking point and thermal deformation due to the other tacking point, the thermal deformation due to each tacking point is shifted in the longitudinal direction of the fuel rail portion. The swell is generated in the longitudinal direction of the fuel rail portion.
According to the invention according to claim 4 of the present application, the fuel passage portion is temporarily attached to both ends in the direction orthogonal to the longitudinal direction of the fuel rail portion at the joint portion with the fuel rail portion. Thus, the occurrence of undulation in the longitudinal direction of the fuel rail portion can be suppressed. Therefore, it is possible to reduce the influence of thermal deformation due to temporary attachment.
Furthermore, thermal deformation occurs even in brazing performed after temporary attachment, but by setting the temporary attachment point as in the claims of the present application, the influence of thermal deformation generated by temporary attachment and brazing can be reduced. The need for processing after brazing can be reduced.

It is a fragmentary sectional view showing roughly a cylinder head of an engine provided with high pressure fuel piping concerning an embodiment of the present invention. It is a front view which shows the high pressure fuel piping which concerns on embodiment of this invention. It is a front view which shows the fuel distribution part of a high pressure fuel piping. It is a top view which shows the fuel distribution part of a high pressure fuel piping. It is a side view which shows the fuel distribution part of a high pressure fuel piping. It is a rear view which shows the fuel distribution part of a high pressure fuel piping. FIG. 4 is a cross-sectional view of the fuel distributor along line Y7-Y7 in FIG. It is explanatory drawing for demonstrating the conventional high pressure fuel piping.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, terms that mean a specific direction such as “up”, “down”, “right”, “left” and other terms including those terms are used. In order to facilitate understanding of the referenced invention, the technical scope of the present invention is not limited by the meaning of these terms.

  FIG. 1 is a partial sectional view schematically showing a cylinder head of an engine provided with a high-pressure fuel pipe according to an embodiment of the present invention. FIG. 2 is a front view showing a high-pressure fuel pipe according to an embodiment of the present invention. 3 is a front view showing a fuel distribution part of the high-pressure fuel pipe, FIG. 4 is a top view showing the fuel distribution part of the high-pressure fuel pipe, FIG. 5 is a side view showing the fuel distribution part of the high-pressure fuel pipe, and FIG. FIG. 7 is a cross-sectional view of the fuel distribution section taken along line Y7-Y7 in FIG.

  The engine provided with the high-pressure fuel pipe according to the embodiment of the present invention is not limited to this, but is an in-line four-cylinder engine in which four cylinders are arranged in a row in the crankshaft direction. As shown, the cylinder head 2 of the engine 1 is formed with an injector mounting portion 4 to which the injector 5 is mounted so as to open to the combustion chamber 3 corresponding to the combustion chamber 3 of each cylinder of the engine 1.

  The injector mounting portion 4 is inserted with a tip 5a of an injector 5 for injecting fuel into the combustion chamber 3 of each cylinder through a seal member (not shown), and the injector 5 is mounted on the cylinder head 2 of the engine 1. Yes. The injector 5 is configured such that the base end side 5b opposite to the tip end side 5a is coupled to the fuel distributor 30 of the high-pressure fuel pipe 10 according to the present embodiment.

  As shown in FIG. 2, the high-pressure fuel pipe 10 according to this embodiment corresponds to a tubular fuel rail portion 20 to which high-pressure fuel pumped from a fuel pump (not shown) is supplied, and to each cylinder from the fuel rail portion 20. A fuel distributor 30 that distributes and supplies high-pressure fuel to the injector 5 that is provided in this manner, and a fastening boss 40 that attaches the high-pressure fuel pipe 10 to the engine 1. In the present embodiment, corresponding to the in-line four-cylinder engine 1, the high-pressure fuel pipe 10 includes four fuel distribution portions 30 and four fastening boss portions 40 that are the same number as the number of cylinders of the engine 1.

  The fuel rail portion 20 is a pipe member formed in a tubular shape using, for example, an iron-based material, and is disposed so as to extend in the cylinder row direction of the engine 1 in which a plurality of cylinders are arranged in a row. The fuel rail portion 20 includes a fuel supply passage 21 extending in the longitudinal direction of the fuel rail portion 20 therein, and the fuel supply passage 21 has an introduction port provided at one end in the longitudinal direction of the fuel rail portion 20. An extremely high pressure fuel is supplied from a fuel pump (not shown) through 22. Further, the fuel rail portion 20 is formed with a substantially circular opening 23 corresponding to each injector 5 that opens in a direction orthogonal to the longitudinal direction thereof.

  On the other hand, the fuel distribution part 30 is integrally cast by a precision casting method such as a lost wax method using, for example, an iron-based material, and the fuel passage part 31 joined to the fuel rail part 20 and the injector 5 are accommodated. The cup part 35 is provided integrally with the fuel passage part 31 on the opposite side of the joint part 32 of the fuel passage part 31 with the fuel rail part 20.

  The fuel passage portion 31 is formed in a substantially cylindrical shape, and has a distribution passage 33 for distributing and supplying high-pressure fuel from the fuel rail portion 20 to the injector 5 therein, and a direction orthogonal to the longitudinal direction of the fuel rail portion 20. It is provided so that it may extend. As shown in FIG. 7, one end of the fuel passage portion 31 is joined to the fuel rail portion 20 so that the opening 23 of the fuel rail portion 20 communicates with the distribution passage 33. In the fuel passage portion 31, the joint portion 32 with the fuel rail portion 20 is formed in a curved shape substantially along the outer periphery of the fuel rail portion 20, and is closer to the cup portion 35 side than the joint portion 32 with the fuel rail portion 20. The cross-sectional area is small.

  The cup part 35 includes an injector accommodating part 36 in which the injector 5 is accommodated, and is formed in a cup shape. The injector accommodating portion 36 is formed in a substantially circular cross section corresponding to the injector 5, and one end of the injector accommodating portion 36 can be coupled to the base end side 5 b of the injector 5 via the seal member 7 to be coupled to the injector 5. The other end is formed in a substantially conical shape. In the cup portion 35, a communication passage 37 communicating with the distribution passage 33 of the fuel passage portion 31 is formed in a substantially conical portion of the injector housing portion 36.

  Thereby, in the high pressure fuel pipe 10, the fuel distributor 30 sends the high pressure fuel supplied to the fuel rail portion 20 from the fuel rail portion 20 to the distribution passage 33 of the fuel passage portion 31, the communication passage 37 of the cup portion 35, and It can be distributed and supplied to the injectors 5 accommodated in the cup part 35 via the injector accommodating part 36 of the cup part 35.

  In the present embodiment, the center axis C1 of the cup portion 35 and the center axis C2 of the fuel passage portion 31 are not limited to this, but are provided so as to extend in a direction orthogonal to the longitudinal direction of the fuel rail portion 20. In addition, the axial direction of the injector 5 accommodated in the cup part 35 and the longitudinal direction of the fuel rail part 20 are shifted from each other at a direction that intersects with the longitudinal direction of the fuel rail part 20 at approximately 135 degrees. Is arranged.

  The fastening boss portion 40 is for attaching the high-pressure fuel pipe 10 to the engine 1, is formed in a substantially cylindrical shape, and is provided in the vicinity of the cup portion 35. As shown in FIG. 4, in this embodiment, the center axis C <b> 1 of the cup portion 35 and the center axis C <b> 3 of the fastening boss portion 40 extend in parallel to the direction perpendicular to the longitudinal direction of the fuel rail portion 20, and the fuel rail portion 20. Are spaced apart in the longitudinal direction.

  The fastening boss portion 40 has an engine mounting hole 41 for inserting a fastening member (not shown) such as a fastening bolt at the center thereof. The fastening boss portion 40 has both end surfaces in the axial direction of the fastening boss portion 40 formed substantially in parallel, and one end surface 42 is in contact with a seat surface 2a provided on the cylinder head 2 of the engine 1, The fastening member is inserted from the other end face 43 through the engine mounting hole 41 so that the fastened portion (not shown) provided on the cylinder head 2 side and the fastening member are fastened and attached to the engine 1. It has become.

  As shown in FIG. 3, the fastening boss portion 40 has an end surface 42 attached to the engine 1, and the shaft of the injector 5 accommodated in the cup portion 35 from the opening end portion 38 on the side where the injector 5 of the cup portion 35 is accommodated. It is arranged in a direction from the distal end side 5a of the injector 5 in the direction toward the proximal end side 5b, and is arranged in a substantially horizontal direction of the closed end portion 39 opposite to the opening end portion 38 of the cup portion 35.

  In the present embodiment, the fastening boss portion 40 is formed using, for example, an iron-based material, and is formed integrally with the fuel distribution portion 30 by a precision casting method such as a lost wax method. The fuel distribution part 30 formed integrally with the fastening boss part 40 also includes a first connection part 51 and a second connection part 52 that connect the cup part 35 and the fastening boss part 40.

  The first connecting portion 51 is formed so as to extend obliquely from the cup portion 35 in a direction from the distal end side 5a of the injector 5 toward the proximal end side 5b with respect to the axial direction of the injector 5 accommodated in the cup portion 35. The second connecting portion 52 is formed to extend horizontally in a direction orthogonal to the axial direction of the injector 5 accommodated in the cup portion 35, and the first connecting portion 51 and the second connecting portion 52 are integrated. Is formed.

  As described above, the fuel distribution unit 30 extends while inclining with respect to the axial direction of the injector 5 accommodated in the cup portion 35, and connects the cup portion 35 and the fastening boss portion 40. Fastened to the cup part 35 by including a second connecting part 52 that extends in a direction orthogonal to the axial direction of the injector 5 accommodated in the cup part 35 and connects the cup part 35 and the fastening boss part 40. The reaction force acting on the cup portion 35 due to the fuel injection of the injector 5 is effectively dispersed in the fastening boss portion 40 while reducing the weight as compared with the case where the entire boss portion 40 is integrally connected. be able to.

  The fuel distribution part 30 and the fastening boss part 40 shown in FIG. 3 to FIG. 7 show two things on the right side of the four fuel distribution parts 30 and the fastening boss part 40 in FIG. The two fuel distribution portions 30 and the left two of the fastening boss portions 40 have the same configuration except that the arrangement of the fuel distribution portion 30 and the fastening boss portion 40 is symmetrical in the longitudinal direction of the fuel rail portion 20. I have.

  When manufacturing the high-pressure fuel pipe 10 configured as described above, first, a fuel passage portion 31 having a distribution passage 33 for distributing and supplying high-pressure fuel from the fuel rail portion 20 to the injector 5, and a fuel passage portion. The fuel distribution unit 30 is formed integrally with the cup 31 and includes the cup part 35 in which the injector 5 is accommodated, and the fastening boss part 40 is provided in the vicinity of the cup part 35 and formed integrally with the fastening boss part 40. And a fuel rail portion 10 are prepared.

  Then, the fuel passage portion 31 of the fuel distribution portion 30 is temporarily attached to the fuel rail portion 10. The fuel passage portion 31 is temporarily attached to each end of the joint portion 32 with the fuel rail portion 20 in the direction orthogonal to the longitudinal direction of the fuel rail portion 20. Specifically, the fuel passage portion 31 and the fuel rail portion 20 are temporarily attached to portions 55 and 56 shown by hatching in FIG. 3 and FIG.

  For example, TIG welding or a CMT process (Cold Metal Transfer) can be used for the tacking, but a CMT process is preferably used. In the CMT process, by controlling the operation of the welding wire, a welding process is performed in which welding is performed by moving the welding wire relative to the base material when an arc is generated. Since the wire can be pulled back to the base material to cut the droplets and the cold process that keeps the short-circuit current low is repeated alternately, the heat input by the arc can be reduced. And the thermal deformation of the fuel rail portion can be suppressed.

  Then, after the fuel passage portion 31 is temporarily attached to the fuel rail portion 20, the fuel passage portion 31 and the fuel rail portion 20 are brazed. In this way, the fuel distribution part 31 is joined to the fuel rail part 20, and the high-pressure fuel pipe 10 according to the present embodiment is manufactured.

  The high pressure fuel pipe 10 manufactured in this way attaches the fastening boss part 40 to the cylinder head 2, so that the fuel distributor 30, specifically the cup part 35, is attached to the injector 5 attached to the cylinder head 2. The high-pressure fuel can be distributed and supplied from the fuel rail portion 20 to the injector 5.

  As described above, in the high-pressure fuel piping structure 10 according to the present embodiment, the fuel distribution unit 30 has the distribution passage 33 for distributing and supplying high-pressure fuel from the fuel rail unit 20 to the injector 5. A fuel passage portion 31 joined to the fuel passage portion 31 and a cup portion 35 formed integrally with the fuel passage portion 31 on the opposite side of the fuel rail portion 20 of the fuel passage portion 31 and accommodating the injector 5. 40 is provided in the vicinity of the cup portion 35 and is formed integrally with the fuel distribution portion 30. Thereby, when attaching to the engine 1, the fuel distribution part 30 and the fastening boss | hub part 40 are integrally formed compared with the case where a fuel distribution part and a fastening boss | hub part are each attached to a fuel rail part. Therefore, the fitting between the base end side 5b of the injector 5 and the cup portion 35 is difficult, and the injector 5 and the fuel distribution portion 30 are not well coupled, and a gap is formed between the injector 5 and the fuel distribution portion 30. Thus, the occurrence of fuel leakage can be suppressed.

  Further, since the fuel distribution portion 30 and the fastening boss portion 40 are integrally formed, the fuel rail portion 20 can be attached to the fuel rail portion as compared with the case where the fuel distribution portion and the fastening boss portion are respectively attached to the fuel rail portion. Since the number of joints can be reduced, the fuel rail portion 20 can be prevented from being thermally deformed. When the fuel rail portion 20 is attached to the engine 1, the base end side 5b of the injector 5 and the cup portion 35 are fitted. It is possible to further suppress the occurrence of fuel leakage due to twisting. When thermal deformation of the fuel rail part is large, a process for machining the portion of the cup part in which the injector is accommodated after joining is necessary to ensure a good fitting state between the base end side of the injector and the cup part. However, there is no need to perform such processing, workability can be improved, and manufacturing costs can be reduced.

  Further, since the fuel distribution part 30 and the fastening boss part 40 are integrally formed, the reaction force acting on the cup part 35 accompanying the fuel injection of the injector 5 can be dispersed in the fastening boss part 40. Therefore, it is possible to suppress the twisting and bending moments from acting on the fuel rail portion 20 and to improve the reliability of the high-pressure fuel piping structure 10.

  Further, the fuel passage portion 31 has a smaller cross-sectional area on the cup portion 35 side than the joint portion 32 with the fuel rail portion 20. As a result, when variations occur in the mounting positions of the plurality of fuel distribution portions 30 joined to the fuel rail portion 20, the fuel passage portion 31 is displaced and acts to absorb the variations. Accordingly, it is possible to suppress a torsional or bending moment from acting on the fuel rail portion 20 when being attached to the engine 1.

  Further, the fuel passage portion 31 is brazed to the fuel rail portion 20 after being temporarily attached to the fuel rail portion 20 and joined to the fuel rail portion 20, so that the fuel passage portion 31 is joined to the fuel rail portion 20 by brazing. By performing the temporary attachment, the joining accuracy of the fuel distribution unit 30 to the fuel rail unit 20 can be improved, and the joining quality between the fuel rail unit 20 and the fuel distribution unit 31 can be improved.

Furthermore, the fuel passage portion 31 is temporarily attached at one end to both ends of the joint portion 32 with the fuel rail portion 20 in the direction orthogonal to the longitudinal direction of the fuel rail portion 20. When there is only one temporary attachment point between the fuel passage portion 31 and the fuel rail portion 20, a gap may be generated between the joint surfaces of the fuel passage portion 31 and the fuel rail portion 20. By setting the two points, it is possible to suppress the generation of a gap between the joint surfaces.
Further, when the temporary attachment points are not set at both ends in the direction orthogonal to the longitudinal direction of the fuel rail portion 20, for example, one temporary attachment point and the other temporary attachment point are respectively in the longitudinal direction of the fuel rail portion 20. In the case where there is a deviation, there is no thermal deformation due to one temporary attachment point and thermal deformation due to the other temporary attachment point in the orthogonal direction, so thermal deformation due to each temporary attachment point is in the longitudinal direction of the fuel rail portion 20. They are generated in a shifted manner, and undulation is generated in the longitudinal direction of the fuel rail portion 20.
In the present embodiment, the fuel passage portion 31 is temporarily attached to both ends of the joint portion 32 with the fuel rail portion 20 in the direction orthogonal to the longitudinal direction of the fuel rail portion 20, as described above. It is possible to suppress the occurrence of undulation in the longitudinal direction of the fuel rail portion 20. Therefore, it is possible to reduce the influence of thermal deformation due to temporary attachment.
Furthermore, thermal deformation occurs even in brazing performed after temporary brazing. However, by setting the temporary mounting point as described above, the influence of thermal deformation generated by temporary mounting and brazing can be reduced. The need for subsequent processing can be reduced.

  In the present embodiment, the four fuel distribution portions 30 integrally formed with the fastening boss portions 40 are attached to the fuel rail portion 20 corresponding to the four-cylinder engine. Similarly, in the engine, as many fuel distribution portions 30 as the number of cylinders in which the fastening boss portions 40 are integrally formed are attached to the fuel rail portion 20.

  As described above, the present invention is not limited to the illustrated embodiments, and it goes without saying that various improvements and design changes can be made without departing from the gist of the present invention.

  The present invention can suppress the occurrence of fuel leakage when a high-pressure fuel pipe for supplying high-pressure fuel to an injector is attached to an engine, and can prevent the torsion and bending moment from acting on the fuel rail portion. It is possible to provide a high-pressure fuel pipe that can be used, and it can be used for an in-line direct injection engine in which a plurality of cylinders are arranged in a row.

DESCRIPTION OF SYMBOLS 1 Engine 5 Injector 10 High pressure fuel piping 20 Fuel rail part 30 Fuel distribution part 31 Fuel passage part 32 Joint part 33 Distribution path 35 Cup part 40 Fastening boss part 51 1st connection part 52 2nd connection part

Claims (4)

A plurality of cylinders arranged in a row and extending in the cylinder row direction of the engine, a tubular fuel rail portion to which high-pressure fuel is supplied, and injectors provided corresponding to the respective cylinders from the fuel rail portion A high-pressure fuel piping structure that distributes and supplies high-pressure fuel from the fuel rail portion to the injector; and a fuel distribution portion that distributes and supplies, and a fastening boss portion that is attached to the engine.
The fuel distributor is
A fuel passage portion that has a distribution passage for distributing and supplying high-pressure fuel from the fuel rail portion to the injector, and is joined to the fuel rail portion;
A cup portion formed integrally with the fuel passage portion on the opposite side of the fuel rail portion of the fuel passage portion, and containing the injector;
A first connecting part extending obliquely with respect to the axial direction of the injector housed in the cup part, and connecting the cup part and the fastening boss part;
A second connecting portion extending in a direction orthogonal to the axial direction of the injector housed in the cup portion, and connecting the cup portion and the fastening boss portion;
With
The fastening boss portion is provided in the vicinity of the cup portion and formed integrally with the fuel distribution portion.
A high-pressure fuel piping structure characterized by that. The fuel passage portion is formed with a smaller cross-sectional area on the cup portion side than the joint portion with the fuel rail portion.
The high-pressure fuel piping structure according to claim 1. The fuel passage portion is brazed to the fuel rail portion after being temporarily attached, and joined to the fuel rail portion.
The high-pressure fuel piping structure according to claim 1 or 2, characterized by the above. The fuel passage portion is temporarily attached to each end portion in a direction orthogonal to the longitudinal direction of the fuel rail portion at a joint portion with the fuel rail portion.
The high-pressure fuel piping structure according to claim 3.

Images