JP2023158212A - fuel injection system - Google Patents

Abstract

To provide a fuel injection system capable of suppressing distortion of an injector during attachment of components.SOLUTION: A fuel injection system 3 includes a bracket 5 fixed to a cylinder head 21 of an engine 2, a fuel accumulator 6 supported and fixed by the bracket 5 and accumulating fuel supplied from a fuel pump, and an injector 7 directly connected with the fuel accumulator 6 and attached to the cylinder head 21 so as to inject the fuel supplied from the fuel accumulator 6 to a combustion chamber. At least one of the fuel accumulator 6 and the bracket 5 has guide members 64, 513 for guiding the injector 7 to an attachment position of the cylinder head 21.SELECTED DRAWING: Figure 3

Description

The present invention relates to a fuel injection system that injects fuel into a combustion chamber of an engine.

Patent Document 1 discloses an internal combustion engine equipped with a common rail. The common rail described in Patent Document 1 is fixed to the lower part of the head cover via two attachment parts integrally formed on the cylindrical body of the common rail, and supplies high-pressure fuel to the injector. The injector described in Patent Document 1 is attached to a cylinder head, and injects high-pressure fuel supplied from a common rail into the cylinder. In the internal combustion engine described in Patent Document 1, the common rail and the injector are connected to each other by a fuel pipe.

On the other hand, there is a fuel injection system in which an injector is directly connected to a common rail without using a fuel pipe. In such a fuel injection system, when assembling parts such as the injector and common rail, it is necessary to fix the common rail to the head cover or cylinder head without determining the position of the injector to the cylinder head, or to fix the common rail to the head cover or cylinder head. If the common rail is fixed to a support member called a bracket or the like fixed to the cylinder head, there is a risk that, for example, a bending load will be applied to the injector directly connected to the common rail. If, for example, a bending load is applied to the injector, there is a risk that the injector will be distorted.

When distortion occurs in the injector, the attitude of the injector deviates from the designed attitude, which may greatly affect the amount of fuel injection. The amount of fuel injected by an injector affects engine performance and exhaust gas performance. Therefore, it is desirable that the injector be assembled while maintaining its designed attitude.

Therefore, one solution is to assemble parts such as the injector and common rail using a special jig or special tool, and then mount the injector to the cylinder head. However, using dedicated jigs and special tools increases the number of steps in the process of assembling parts such as injectors and common rails, and requires dedicated jigs and special tools for after-sales maintenance in the market. There's a problem.

Patent No. 6468687

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a fuel injection system that can suppress the occurrence of distortion in an injector during assembly of parts.

The problem is a fuel injection system that injects fuel into a combustion chamber of an engine, which includes a bracket that is fixed to a cylinder head of the engine, and a bracket that is supported and fixed to the bracket and that injects the fuel supplied from a fuel pump. a fuel pressure accumulation device for accumulating pressure; and an injector connected directly to the fuel pressure accumulation device and attached to the cylinder head to inject the fuel supplied from the fuel pressure accumulation device into the combustion chamber, The problem is solved by the fuel injection system according to the present invention, characterized in that at least one of the pressure accumulator and the bracket has a guide member that guides the injector to the mounting position of the cylinder head.

According to the fuel injection system according to the present invention, the fuel pressure accumulating device that accumulates pressure of the fuel supplied from the fuel pump is supported and fixed to the bracket fixed to the cylinder head of the engine. Further, an injector that injects fuel supplied from the fuel pressure accumulator into the combustion chamber of the engine is directly connected to the fuel pressure accumulator and mounted on the cylinder head. Here, at least one of the fuel pressure accumulator and the bracket includes a guide member that guides the injector to the mounting position of the cylinder head. Therefore, when the fuel accumulator is assembled and fixed to the bracket, even if the position of the injector relative to the cylinder head is not determined, the fuel accumulator uses the guide member to guide the injector to the mounting position of the cylinder head. While doing so, it is assembled and fixed to the bracket. As a result, in the fuel injection system according to the present invention, when the fuel pressure accumulator is assembled and fixed to the bracket, and when the injector is attached to the cylinder head, the injector connected to the fuel pressure accumulator is subjected to a bending load, etc. Therefore, it is possible to suppress the occurrence of distortion in the injector.

Further, since the fuel pressure accumulator is assembled and fixed to the bracket while guiding the injector to the mounting position of the cylinder head using the guide member, a dedicated jig and special tools are not required. Thereby, the fuel injection system according to the present invention can suppress an increase in the number of steps in the step of assembling the fuel pressure accumulator to the bracket and the step of assembling the injector to the cylinder head. Further, the fuel injection system according to the present invention can eliminate the need for dedicated jigs and special tools during after-market maintenance.

In the fuel injection system according to the present invention, preferably, the guide member includes a convex portion provided on one of the fuel pressure accumulator and the bracket, and a convex portion provided on the other of the fuel pressure accumulator and the bracket. It is characterized by having a recessed part into which the said convex part fits.

According to the fuel injection system according to the present invention, since the convex portion fits into the concave portion, the guide member can more reliably guide the injector to the mounting position of the cylinder head. In other words, the guide member is used as an insertion guide when the fuel accumulator is assembled to the bracket and when the injector is attached to the cylinder head. Therefore, when the fuel accumulator is assembled and fixed to the bracket, even if the position of the injector with respect to the cylinder head is not determined, the fuel accumulator uses the guide member to ensure that the injector is installed in the cylinder head at the mounting position. can be guided to. As a result, in the fuel injection system according to the present invention, when the fuel pressure accumulator is assembled and fixed to the bracket, and when the injector is attached to the cylinder head, the injector connected to the fuel pressure accumulator is subjected to a bending load, etc. Therefore, it is possible to further suppress the occurrence of distortion in the injector.

In the fuel injection system according to the present invention, preferably, the injector is attached to the cylinder head by being inserted into an insertion hole formed in the cylinder head, and the direction in which the convex part fits into the concave part is The direction in which the injector is inserted into the insertion hole is parallel to the direction in which the injector is inserted into the insertion hole.

According to the fuel injection system according to the present invention, the direction in which the convex portion fits into the concave portion is parallel to the direction in which the injector is inserted into the insertion hole. Therefore, the direction in which the fuel accumulator is assembled and fixed to the bracket is parallel to the direction in which the injector is inserted into the insertion hole. Therefore, the fuel pressure accumulator advances parallel to the insertion direction of the injector into the insertion hole while guiding the injector to the mounting position of the cylinder head using the guide member, and is assembled and fixed to the bracket. As a result, in the fuel injection system according to the present invention, when the fuel pressure accumulator is assembled and fixed to the bracket, and when the injector is attached to the cylinder head, the injector connected to the fuel pressure accumulator is subjected to a bending load, etc. Therefore, it is possible to further suppress the occurrence of distortion in the injector.

In the fuel injection system according to the present invention, preferably, the guide member has a plurality of convex portions and a plurality of concave portions into which each of the plurality of convex portions fits.

According to the fuel injection system according to the present invention, the guide member has a plurality of convex portions and a plurality of concave portions. Each of the plurality of protrusions fits into each of the plurality of recesses. Therefore, the guide member is used as an insertion guide at a plurality of positions when the fuel accumulator is assembled to the bracket and when the injector is mounted to the cylinder head. Therefore, the fuel accumulator is assembled and fixed to the bracket while the guide member guides the injector to the mounting position of the cylinder head at a plurality of positions. As a result, the fuel injection system according to the present invention can further suppress bending loads etc. from being applied to the injector connected to the fuel pressure accumulator without using a dedicated jig or special tools, thereby preventing distortion of the injector. This can be further suppressed.

In the fuel injection system according to the present invention, preferably, when the injector is attached to the cylinder head, the convex portion starts to fit into the recess before the position of the injector with respect to the cylinder head is determined. shall be.

According to the fuel injection system according to the present invention, when the injector is mounted on the cylinder head, the guide member can start guiding the injector to the mounting position of the cylinder head before the position of the injector with respect to the cylinder head is determined. As a result, in the fuel injection system according to the present invention, when the fuel pressure accumulator is assembled and fixed to the bracket, and when the injector is attached to the cylinder head, the injector connected to the fuel pressure accumulator is subjected to a bending load, etc. Therefore, it is possible to further suppress the occurrence of distortion in the injector.

In the fuel injection system according to the present invention, preferably, the fuel pressure accumulator is fixed to the bracket using a first fastening member, the bracket is fixed to the cylinder head using a second fastening member, and the fuel accumulator is fixed to the cylinder head using a second fastening member, A first fixing part that engages with the first fastening member, a second fixing part having a hole through which the second fastening member passes, and a reinforcing part that connects and reinforces the first fixing part and the second fixing part that are adjacent to each other. It is characterized by being formed in a ladder shape or a lattice shape.

According to the fuel injection system according to the present invention, the fuel pressure accumulator is fixed to the bracket using the first fastening member. The bracket is secured to the cylinder head using a second fastening member. Further, the bracket connects and reinforces a first fixing part that engages with the first fastening member, a second fixing part having a hole through which the second fastening member passes, and the first fixing part and second fixing part that are adjacent to each other. The reinforcing portion is formed in a ladder shape or a lattice shape. Thereby, the fuel injection system according to the present invention can reduce the number of parts while reinforcing the fixing structure of the fuel pressure accumulator and the injector using the ladder-shaped or grid-shaped bracket.

According to the present invention, it is possible to provide a fuel injection system that can suppress distortion of an injector during assembly of parts.

1 is a perspective view showing an engine equipped with a fuel injection system according to the present invention. FIG. 1 is an exploded view showing an engine equipped with a fuel injection system according to the present embodiment. FIG. 1 is an enlarged perspective view of the fuel injection system according to the present embodiment. FIG. 4 is a plan view of the fuel injection system according to the present embodiment when viewed in the direction of arrow A11 shown in FIG. 3. FIG. It is a top view showing the bracket of this embodiment. FIG. 1 is a perspective view of the fuel injection system according to the present embodiment, viewed diagonally from above. It is a top view showing the arrangement relationship between the bracket and the cylinder head of this embodiment. It is a top view showing the cylinder head of this embodiment. FIG. 2 is a perspective view of the fuel pressure accumulator according to the present embodiment as viewed diagonally from below.

Below, preferred embodiments of the present invention will be described in detail with reference to the drawings.
The embodiments described below are preferred specific examples of the present invention, and therefore have various technically preferable limitations. However, the scope of the present invention does not particularly limit the present invention in the following description. Unless otherwise specified, the embodiments are not limited to these embodiments. Further, in each drawing, similar components are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

FIG. 1 is a perspective view showing an engine equipped with a fuel injection system according to the present invention.
FIG. 2 is an exploded view showing an engine equipped with a fuel injection system according to this embodiment.
1 and 2, for convenience of explanation, parts provided below the cylinder head of the engine (for example, a cylinder block, a crankcase, etc.) are omitted. Further, in FIG. 2, the fuel pipe 61 is omitted for convenience of explanation.

The engine 2 shown in FIGS. 1 and 2 is, for example, an industrial diesel engine, and is installed in an industrial machine such as a construction machine, an agricultural machine, or a lawn mower. The engine 2 is an in-line multi-cylinder engine, and in the example shown in FIGS. 1 and 2, it is an in-line three-cylinder engine. The engine 2 is, for example, an indirect injection (IDI) diesel engine. However, the engine 2 according to this embodiment is not limited to an in-line three-cylinder engine. Further, the engine 2 according to the present embodiment is not limited to a pre-chamber type diesel engine.

The engine 2 includes a cylinder head 21, a head cover 22, an intake manifold 23, and a fuel injection system 3. The fuel injection system 3 is provided at the top of the cylinder head 21. In this specification, the vertical direction corresponds to the vertical direction of an industrial machine such as a construction machine, an agricultural machine, or a lawn mower when the engine 2 is mounted on the industrial machine.

The fuel injection system 3 according to this embodiment includes a bracket 5, a fuel pressure accumulator 6, an injector 7, and a harness 8.

The bracket 5 is fixed to the upper part of the cylinder head 21 using a plurality of second fastening members 59. In the fuel injection system 3 according to this embodiment, the bracket 5 is fixed to the cylinder head 21 using three second fastening members 59. Specifically, the second fastening member 59 passes through a hole 521 (see FIG. 5) formed in the second fixing part 52 (see FIG. 5) of the bracket 5 from above to below, and connects to the upper part of the cylinder head 21. It engages with a female thread 213 formed in the. Thereby, the bracket 5 is fastened to the cylinder head 21 using the plurality of second fastening members 59. Details of the bracket 5 will be described later.

The fuel pressure accumulating device 6 is a so-called common rail fuel injection device, and accumulates fuel, which is pressurized by a fuel pump (not shown) and supplied through a fuel pipe 61, in the common rail. The fuel accumulator 6 is fixed to the bracket 5 using a plurality of first fastening members 62 . In the fuel injection system 3 according to this embodiment, the fuel pressure accumulator 6 is fixed to the bracket 5 using three first fastening members 62. Specifically, the first fastening member 62 passes through a hole 63 (see FIG. 9) provided in the fuel accumulator 6 from above to below, and connects to a female thread formed in the first fixing portion 51 of the bracket 5. It meshes with 511. Thereby, the fuel pressure accumulator 6 is fastened to the bracket 5 using the plurality of first fastening members 62. In the bracket 5 shown in FIG. 2, recesses 513 are formed above the female threads 511 in the two first fixing parts 51 at both ends of the three first fixing parts 51. Details of the recessed portion 513 will be described later.

The injector 7 is directly connected to the fuel accumulator 6, as shown in FIG. As mentioned above, the engine 2 shown in FIGS. 1 and 2 is an in-line three-cylinder engine. Therefore, in the fuel injection system 3 according to the present embodiment, the three injectors 7 are directly connected to the fuel pressure accumulator 6 and arranged side by side along the arrangement direction A1. Further, the injector 7 is attached to the cylinder head 21. Specifically, as shown in FIG. 2, the lower part of the injector 7 is inserted into the insertion hole 212 formed in the cylinder head 21. In the engine 2 shown in FIG. 2, a sleeve 211 is press-fitted into an insertion hole 212 and fixed to the cylinder head 21. Therefore, in the engine 2 shown in FIG. 2, the hole provided in the sleeve 211 forms a part of the insertion hole 212. The sleeve 211 determines the insertion position of the injector 7 with respect to the insertion hole 212. Note that the sleeve 211 does not necessarily have to be provided.

The harness 8 is connected to the injector 7 at a connecting portion 81 called a coupler or the like, and supplies power to the injector 7 . For example, the injector 7 receives electric power that is controlled by an electronic control unit (ECU) based on a detection signal related to the engine rotation speed, a detection signal related to the accelerator opening, etc., and is supplied via the harness 8. The needle valve is opened, and the fuel supplied from the fuel accumulator 6 is injected into the combustion chamber 215 of the engine 2 (see FIGS. 7 and 8). For example, the combustion chamber 215 shown in FIGS. 7 and 8 is an auxiliary chamber (ie, an auxiliary combustion chamber) provided in the cylinder head 21. However, the combustion chamber into which the injector 7 of this embodiment injects fuel is not limited to only the auxiliary chamber. In this way, the harness 8 is a harness for driving the injector 7, that is, a harness for driving the injector.

The harness 8 is held by a holding member 82 and fixed to the bracket 5 via the holding member 82. Specifically, as shown in FIGS. 1 and 2, the holding member 82 holds the harness 8, and the protrusion 821 of the holding member 82 fits into the hole 531 formed in the third fixing part 53 of the bracket 5. By being inserted, it is attached to the bracket 5. Thereby, the harness 8 is fixed to the bracket 5 via the holding member 82. Examples of the holding member 82 include a binding band that is attached to the outer periphery of the harness 8 and holds the harness 8. However, the harness 8 is not limited to a cable tie.

FIG. 3 is an enlarged perspective view of the fuel injection system according to this embodiment.
FIG. 4 is a plan view of the fuel injection system according to this embodiment when viewed in the direction of arrow A11 shown in FIG.
FIG. 5 is a plan view showing the bracket of this embodiment.

First, details of the bracket of this embodiment will be explained with reference to FIG.
As shown in FIG. 5, the bracket 5 of this embodiment is formed in a ladder shape or a lattice shape. Specifically, the bracket 5 includes a first fixing part 51, a second fixing part 52, a third fixing part 53, a first reinforcing part 541, a second reinforcing part 542, and a third reinforcing part 543. , has.

The first fixing portion 51 has a female thread 511 that engages with the male thread of the first fastening member 62 . As shown in FIG. 5, the bracket 5 of this embodiment has three first fixing parts 51. The three first fixing parts 51 are arranged in parallel with each other along the arrangement direction A1 of the three injectors 7. As shown in FIG. 5, in the two first fixing parts 51 at both ends of the three first fixing parts 51, a recess 513 is formed in the upper part of the female thread 511. The recess 513 constitutes a part of the "guiding member" of the present invention, and has an inner circumferential surface parallel to the insertion direction of the injector 7 and the advancing direction of the first fastening member 62. In other words, the axis of the recess 513 is parallel to the direction in which the injector 7 is inserted and the direction in which the first fastening member 62 moves.

Note that the concave portions 513 are not limited to being formed in the two first fixing portions 51 at both ends of the three first fixing portions 51, but may be formed corresponding to the convex portions 64 (see FIG. 3). It would be fine if it had been done. For example, the recess 513 may be formed above the female thread 511 in all three first fixing parts 51. Furthermore, it is desirable that the recessed portions 513 be formed in at least two of the three first fixing portions 51 in order to further improve the guiding accuracy and positioning accuracy in the horizontal direction. For example, the recess 513 may be formed in the upper part of the female thread 511 in the central first fixing part 51 and the first fixing part 51 at either end of the three first fixing parts 51 . Further, the recess 513 only needs to be formed corresponding to the protrusion 64, and does not necessarily have to be formed on the upper part of the female screw 511, and does not need to be formed coaxially with the axis of the female screw 511. good.

The second fixing portion 52 has a hole 521 through which, for example, a male thread of the second fastening member 59 can pass. As shown in FIG. 5, the bracket 5 of this embodiment has three second fixing parts 52. The three second fixing parts 52 are arranged side by side with each other along the arrangement direction A1 of the three injectors 7, and are separated from the three first fixing parts 51 in the direction intersecting the arrangement direction A1 of the three injectors 7. are located far apart.

The third fixing portion 53 has a hole 531 into which the protrusion 821 of the holding member 82 can be inserted. As shown in FIG. 5, the bracket 5 of this embodiment has three third fixing parts 53. The three third fixing parts 53 are arranged in parallel with each other along the arrangement direction A1 of the three injectors 7, and are separated from the three first fixing parts 51 in the direction intersecting the arrangement direction A1 of the three injectors 7. are located far apart. Further, the third fixing part 53 is provided near the second fixing part 52.

The first reinforcing part 541 connects the first fixing part 51 and the second fixing part 52 that are adjacent to each other, and reinforces the bracket 5. The second reinforcing portion 542 connects the first fixing portions 51 adjacent to each other and reinforces the bracket 5. The third reinforcing portion 543 connects the second fixing portions 52 adjacent to each other and reinforces the bracket 5.
The bracket 5 of this embodiment has the structure described above and is formed in a ladder shape or a lattice shape.

Next, the assembly of the bracket 5 and the fuel pressure accumulator 6 will be described with reference to FIGS. 3 and 4.
As described above with respect to FIGS. 1 and 2, the injector 7 of this embodiment is directly connected to the fuel accumulator 6. As shown in FIGS. 3 and 4, when the fuel pressure accumulator 6 is fastened to the bracket 5 using the first fastening member 62, the injector 7 is attached to, for example, an O-ring (not shown) attached to the injector 7. It is held in advance in the insertion hole 66 (see FIG. 9) of the fuel pressure accumulating device 6 by a screw or the like.

As shown in FIG. 4, a biasing member 72 such as a leaf spring is attached to the injector 7. When the injector 7 is attached to the cylinder head 21 (see FIGS. 1 and 2), the biasing member 72 applies a biasing force to the fuel pressure accumulator 6 and the cylinder head 21. As shown in FIG. 4, in a state before the injector 7 is attached to the cylinder head 21 and in a state where the injector 7 is held in the insertion hole 66 of the fuel pressure accumulator 6, the injector 7 is inserted into the fuel pressure accumulator It is slightly lifted from 6. That is, the position of the injector 7 with respect to the fuel pressure accumulator 6 is not determined. Further, the position of the injector 7 with respect to the cylinder head 21 is also not determined. After that, when the fuel pressure accumulator 6 is fastened to the bracket 5 using the first fastening member 62, the injector 7 is moved to the fuel pressure accumulator 6 while the biasing member 72 applies a biasing force to the fuel pressure accumulator 6 and the cylinder head 21. and the cylinder head 21. At this time, the position of the injector 7 with respect to the fuel pressure accumulator 6 and the cylinder head 21 is determined.

Here, when the fuel pressure accumulator 6 is fastened to the bracket 5 using the first fastening member 62 while the injector 7 is held in the fuel pressure accumulator 6 and the position of the injector 7 is not determined. For example, there is a possibility that a bending load or the like may be applied to the injector 7 that is directly connected to the fuel pressure accumulator 6. If, for example, a bending load is applied to the injector 7, there is a possibility that the injector 7 will be distorted. When distortion occurs in the injector 7, the attitude of the injector 7 may deviate from the designed attitude, which may affect the fuel injection amount. The fuel injection amount of the injector 7 affects the performance of the engine 2 and the exhaust gas performance. Therefore, it is desirable that the injector 7 be assembled while maintaining the designed attitude.

In contrast, in the fuel injection system 3 according to the present embodiment, the fuel pressure accumulator 6 has a convex portion 64, as shown in FIGS. 3 and 4. The convex portion 64 constitutes a part of the “guiding member” of the present invention, similar to the aforementioned concave portion 513. That is, the "guide member" of the present invention has a convex portion 64 and a concave portion 513. The protrusion 64 is formed corresponding to the recess 513 and fits into the recess 513. In other words, the recess 513 is formed corresponding to the protrusion 64 and is fitted into the protrusion 64 .

The convex portion 64 may be provided on the fuel pressure accumulating device 6 or may be provided on the bracket 5. That is, the convex portion 64 is provided on either the fuel pressure accumulator 6 or the bracket 5. The recess 513 may be provided in the fuel pressure accumulator 6 or in the bracket 5. In other words, the recess 513 is provided on the other of the fuel pressure accumulator 6 and the bracket 5. In the example shown in FIGS. 3 and 4, the protrusion 64 is provided on the fuel accumulator 6, and the recess 513 is provided on the bracket 5.

For example, the convex portion 64 is a pipe pin that fits into the concave portion 513. In the example shown in FIGS. 3 and 4, the pipe pin as the convex portion 64 is formed in the shape of a hollow rod having an inner diameter through which, for example, a male thread of the first fastening member 62 can pass. The outer circumferential surface of one end of the protrusion 64 is press-fitted into the hole 63 (see FIG. 9) of the fuel accumulator 6 and is fixed, and the outer circumferential surface of the other end of the protrusion 64 is fitted into the recess 513 formed in the bracket 5. Fits in. Note that, as described above, the bracket 5 may have the protrusion 64. In this case, the outer circumferential surface of one end of the convex portion 64 is press-fitted into the recess 513 of the bracket 5 and fixed, and the outer circumferential surface of the other end of the convex portion 64 is connected to the hole 63 of the fuel accumulator 6 (i.e., the concave portion). Fits in. In the following description, a case will be exemplified in which the fuel pressure accumulator 6 has a convex portion 64 and the bracket 5 has a concave portion 513.

Note that the protrusion 64 is not limited to a pipe pin. The convex portion 64 only needs to have a shape that fits into the concave portion 513, and may be a solid rod-shaped member. For example, the convex portion 64 may be a sleeve or a collar. The vertical cross-sectional shape of the convex portion 64 is not particularly limited.

As shown in FIG. 3, the fuel injection system 3 according to this embodiment is provided with a plurality of convex portions 64. Specifically, as shown in FIG. 3, two convex portions 64 are fixed to two holes 63 at both ends of the three holes 63 of the fuel accumulator 6. Each of the two convex portions 64 is fitted into each of the two concave portions 513 formed in the bracket 5.

Note that, similarly to the case described above regarding the recess 513, the protrusion 64 is not limited to being fixed to the two holes 63 at both ends of the three holes 63 of the fuel accumulator 6; It is sufficient if it is provided correspondingly. For example, the convex portion 64 may be fixed to all three holes 63 of the fuel accumulator 6. Furthermore, it is desirable that the convex portion 64 be fixed to at least two of the three holes 63 of the fuel accumulator 6 in order to further improve the guiding accuracy and positioning accuracy in the horizontal direction. For example, the convex portion 64 may be fixed to the center hole 63 and the hole 63 at either end of the three holes 63 of the fuel pressure accumulator 6 .

As shown in FIG. 4, the convex portion 64 is fixed to the hole 63 of the fuel pressure accumulator 6 while protruding from the fastening surface 631 (see FIG. 9) of the fuel pressure accumulator 6. Here, when the injector 7 is inserted into the insertion hole 212 of the cylinder head 21 and attached to the cylinder head 21, the protrusion 64 is fitted into the recess 513 of the bracket 5 before the position of the injector 7 with respect to the cylinder head 21 is determined. It starts to get better. In the fuel injection system 3 according to the present embodiment, the injector 7 is inserted into the insertion hole 212 of the cylinder head 21, and the positioning surface 71 of the injector 7 contacts the positioning surface 214 of the cylinder head 21, so that the injector 7 is inserted into the insertion hole 212 of the cylinder head 21. The position of 7 is determined.

Specifically, as shown in FIG. 4, when the injector 7 is inserted into the insertion hole 212 of the cylinder head 21, the tip 641 of the convex portion 64 and the fastening surface 512 of the bracket 5 (i.e., the recess 513 of the bracket 5) The distance D1 is shorter than the distance D2 between the positioning surface 71 of the injector 7 and the positioning surface 214 of the cylinder head 21 (that is, the entrance surface of the insertion hole 212 of the cylinder head 21). Therefore, when the injector 7 is inserted into the insertion hole 212 of the cylinder head 21, the protrusion 64 fits into the recess 513 of the bracket 5 before the positioning surface 71 of the injector 7 contacts the positioning surface 214 of the cylinder head 21. start. Thereby, the convex portion 64 and the concave portion 513 can begin to guide the injector 7 to the mounting position of the cylinder head 21 before the position of the injector 7 with respect to the cylinder head 21 is determined.

Further, as described above, the recess 513 has an inner circumferential surface parallel to the insertion direction of the injector 7 into the insertion hole 212 of the cylinder head 21. In other words, the axis of the recess 513 is parallel to the insertion direction of the injector 7 into the insertion hole 212 of the cylinder head 21. Therefore, the direction in which the convex portion 64 fits into the concave portion 513 is parallel to the direction in which the injector 7 is inserted into the insertion hole 212 of the cylinder head 21 . Therefore, the direction in which the fuel accumulator 6 is assembled and fixed to the bracket 5 is parallel to the direction in which the injector 7 is inserted into the insertion hole 212 of the cylinder head 21.

As a result, the fuel accumulator 6 moves parallel to the insertion direction of the injector 7 into the insertion hole 212 of the cylinder head 21 while guiding the injector 7 to the mounting position of the cylinder head 21 using the convex portion 64 and the concave portion 513. It is assembled and fixed. In this way, the guide member having the convex portion 64 and the concave portion 513 can more reliably guide the injector 7 to the mounting position of the cylinder head 21 by fitting the convex portion 64 into the concave portion 513. That is, when the fuel accumulator 6 is assembled to the bracket 5 and when the injector 7 is attached to the cylinder head 21, the guide member having the convex portion 64 and the concave portion 513 is used as an insertion guide.

As explained above, according to the fuel injection system 3 according to the present embodiment, the fuel pressure accumulating device 6 that accumulates pressure of the fuel supplied from the fuel pump is supported by the bracket 5 fixed to the cylinder head 21 of the engine 2. It is fixed at the same time. Further, an injector 7 that injects fuel supplied from the fuel pressure accumulator 6 into the combustion chamber 215 of the engine 2 (see FIGS. 7 and 8) is directly connected to the fuel pressure accumulator 6 and is attached to the cylinder head 21. be done. Here, at least one of the fuel pressure accumulator 6 and the bracket 5 (in this embodiment, both the fuel pressure accumulator 6 and the bracket 5) includes a guide member (a protrusion 64 and a recessed portion 513). Therefore, when the fuel pressure accumulating device 6 is assembled and fixed to the bracket 5, even if the position of the injector 7 with respect to the cylinder head 21 is not determined, the fuel pressure accumulating device 6 can be attached to the convex portion 64 and the concave portion 513. While guiding the injector 7 to the mounting position of the cylinder head 21, it is assembled and fixed to the bracket 5. Thereby, the fuel injection system 3 according to the present embodiment is connected to the fuel pressure accumulation device 6 when the fuel pressure accumulation device 6 is assembled and fixed to the bracket 5 and when the injector 7 is attached to the cylinder head 21. Therefore, it is possible to suppress the application of a bending load or the like to the injector 7, and to suppress the occurrence of distortion in the injector 7.

Furthermore, since the fuel accumulator 6 is assembled and fixed to the bracket 5 while guiding the injector 7 to the mounting position of the cylinder head 21 using the convex portion 64 and the concave portion 513, a dedicated jig and special tools are not required. Thereby, the fuel injection system 3 according to the present embodiment can suppress an increase in the number of steps in the step of assembling the fuel pressure accumulator 6 to the bracket 5 and the step of assembling the injector 7 to the cylinder head 21. Further, the fuel injection system 3 according to the present embodiment can eliminate the need for dedicated jigs and special tools during after-market maintenance.

Further, the guide member having the convex portion 64 and the concave portion 513 can more reliably guide the injector 7 to the mounting position of the cylinder head 21 by fitting the convex portion 64 into the concave portion 513. That is, when the fuel accumulator 6 is assembled to the bracket 5 and when the injector 7 is attached to the cylinder head 21, the guide member having the convex portion 64 and the concave portion 513 is used as an insertion guide. Therefore, when the fuel pressure accumulating device 6 is assembled and fixed to the bracket 5, even if the position of the injector 7 with respect to the cylinder head 21 is not determined, the fuel pressure accumulating device 6 can be attached to the convex portion 64 and the concave portion 513. The injector 7 can be reliably guided by the mounting position of the cylinder head 21. Thereby, the fuel injection system 3 according to the present embodiment is connected to the fuel pressure accumulation device 6 when the fuel pressure accumulation device 6 is assembled and fixed to the bracket 5 and when the injector 7 is attached to the cylinder head 21. It is possible to further suppress the application of bending loads and the like to the injector 7, and further suppress the generation of distortion in the injector 7.

Further, the direction in which the convex portion 64 fits into the recess 513 is parallel to the direction in which the injector 7 is inserted into the insertion hole 212 of the cylinder head 21 . Therefore, the direction in which the fuel accumulator 6 is assembled and fixed to the bracket 5 is parallel to the direction in which the injector 7 is inserted into the insertion hole 212 of the cylinder head 21. Therefore, the fuel accumulator 6 moves parallel to the insertion direction of the injector 7 into the insertion hole 212 of the cylinder head 21 and into the bracket 5 while guiding the injector 7 to the mounting position of the cylinder head 21 by the convex part 64 and the concave part 513. Assembled and fixed. Thereby, the fuel injection system 3 according to the present embodiment is connected to the fuel pressure accumulation device 6 when the fuel pressure accumulation device 6 is assembled and fixed to the bracket 5 and when the injector 7 is attached to the cylinder head 21. It is possible to further suppress the application of bending loads and the like to the injector 7, and further suppress the generation of distortion in the injector 7.

Further, the guide member includes a plurality of convex portions 64 and a plurality of concave portions 513. Each of the plurality of protrusions 64 fits into each of the plurality of recesses 513. Therefore, the plurality of protrusions 64 and the plurality of recesses 513 are used as insertion guides at a plurality of positions when the fuel accumulator 6 is assembled to the bracket 5 and when the injector 7 is mounted to the cylinder head 21. . Therefore, the fuel pressure accumulator 6 is assembled and fixed to the bracket 5 while guiding the injector 7 to the mounting position of the cylinder head 21 at a plurality of positions using the plurality of convex portions 64 and the plurality of concave portions 513. As a result, the fuel injection system 3 according to the present embodiment can further suppress bending loads etc. from being applied to the injector 7 connected to the fuel pressure accumulator 6 without using a dedicated jig or special tool. Distortion in the injector 7 can be further suppressed.

Furthermore, when the injector 7 is mounted on the cylinder head 21, the convex portion 64 and the recessed portion 513 can begin to guide the injector 7 to the mounting position of the cylinder head 21 before the position of the injector 7 with respect to the cylinder head 21 is determined. . Thereby, the fuel injection system 3 according to the present embodiment is connected to the fuel pressure accumulation device 6 when the fuel pressure accumulation device 6 is assembled and fixed to the bracket 5 and when the injector 7 is attached to the cylinder head 21. It is possible to further suppress the application of bending loads and the like to the injector 7, and further suppress the generation of distortion in the injector 7.

Furthermore, since the injector 7 is directly connected to the fuel pressure accumulator 6, it is possible to suppress fuel pressure loss and reduce the number of parts such as fuel piping and injector fixing brackets. Here, the bracket 5 that supports the fuel pressure accumulator 6 to which the injector 7 is directly connected has a first fixing part 51 that engages with the first fastening member 62 and a second fastening part 51 that has a hole 521 through which the second fastening member 59 passes. It has a fixing part 52 and a first reinforcing part 541 that connects and reinforces the first fixing part 51 and second fixing part 52 that are adjacent to each other, and is formed in a ladder shape or a lattice shape. Thereby, the fuel injection system 3 according to the present embodiment can reinforce the fixing structure of the fuel pressure accumulator 6 and the injector 7 using the bracket 5 formed in a ladder shape or a grid shape. The bracket 5 formed in the shape of a ladder or a grid improves the strength of the fixing structure of the fuel pressure accumulator 6 and the injector 7, so that vibrations occurring in the fuel injection system 3 can be reduced. Moreover, since the vibrations generated in the fuel injection system 3 can be reduced, the noise generated in the fuel injection system 3 can be reduced. Thereby, the fuel injection system 3 according to the present embodiment can suppress the occurrence of fuel pressure loss, reduce the number of parts, and reduce vibration and noise.

The bracket 5 also includes a first reinforcing part 541 that connects and reinforces the first fixing part 51 and second fixing part 52 that are adjacent to each other, and a second reinforcing part 541 that connects and reinforces the first fixing part 51 that is adjacent to each other. portion 542 and a third reinforcing portion 543 that connects and reinforces the second fixing portions 52 adjacent to each other, and is formed in a ladder shape or a lattice shape. Therefore, the strength of the fixing structure of the fuel pressure accumulator 6 and the injector 7 is further improved. Therefore, vibrations occurring in the fuel injection system 3 can be further reduced. Moreover, since the vibrations generated in the fuel injection system 3 can be further reduced, the noise generated in the fuel injection system 3 can be further reduced. Thereby, the fuel injection system 3 according to the present embodiment can suppress the occurrence of fuel pressure loss, reduce the number of parts, and further reduce vibration and noise.

Further, the first fastening member 62 passes through a hole 63 formed in the fuel pressure accumulating device 6 from above and engages with the first fixing portion 51 of the bracket 5 . The second fastening member 59 passes through a hole 521 formed in the second fixing portion 52 of the bracket 5 from above and engages with the cylinder head 21 . Therefore, when assembling and fixing the bracket 5 to the cylinder head 21, the operator engages the second fastening member 59 with the cylinder head 21 from above through the hole 521, and easily fastens the bracket 5 to the cylinder head 21. can be done. In addition, when the worker assembles and fixes the fuel pressure accumulator 6 to which the injector 7 is directly connected to the bracket 5, the operator inserts the first fastening member 62 from above through the hole 63 of the fuel pressure accumulator 6 into the bracket 5. The fuel accumulator 6 to which the injector 7 is directly connected can be easily fastened to the bracket 5 by engaging the first fixing portion 51 of the bracket 5 . Thereby, the fuel injection system 3 according to the present embodiment can facilitate assembly and improve workability.

Further, a sleeve 211 that determines the insertion position of the injector 7 with respect to the insertion hole 212 into which the injector 7 is inserted is press-fitted into the insertion hole 212 of the cylinder head 21 . Therefore, the sleeve 211 can determine the position of the injector 7 more accurately, and can prevent the sleeve 211 itself from rotating in the insertion hole 212. Thereby, the fuel injection system 3 according to the present embodiment can improve the durability and reliability of the injector 7.

FIG. 6 is a perspective view of the fuel injection system according to the present embodiment, viewed diagonally from above.
As described above with reference to FIGS. 1 and 2, the harness 8 is connected to the injector 7 at a connecting portion 81 called a coupler or the like, and is fixed to the bracket 5 via a holding member 82. As shown in FIG. 6, the harness 8 is fixed to the third fixing part 53 of the bracket 5 at a position adjacent to the connecting part 81. Specifically, the harness 8 extends along the arrangement direction A1 of the plurality of injectors 7, and is fixed to the third fixing portion 53 of the bracket 5 at a position between the plurality of injectors 7 adjacent to each other. .

Here, if the harness for driving the injector is fixed to, for example, the head cover 22 (see FIG. 1) or the fuel pipe 61, vibrations of the cylinder head 21, fuel pipe 61, etc. may be transmitted to the harness, and the vibration of the harness may be amplified. There is. If the vibrations of the harness are amplified, there is a risk that the durability of the harness may be reduced or noise may be amplified. Further, if the harness for driving the injector is fixed to, for example, a stay for fixing the harness, the number of parts increases.

On the other hand, according to the fuel injection system 3 according to the present embodiment, the harness 8 (that is, the harness for driving the injector) is connected to the injector 7 and fixed to the bracket 5. As described above with respect to FIGS. 1 and 2, the bracket 5 is fixed to the cylinder head 21. Further, the fuel accumulator 6 is fixed to a bracket 5 fixed to the cylinder head 21 and directly connected to the injector 7. Therefore, the part where the harness 8 is connected to the injector 7 and the part where the harness 8 is fixed to the bracket form the same vibration system via the bracket 5, the fuel pressure accumulator 6, and the injector 7. Thereby, the fuel injection system 3 according to the present embodiment can suppress vibrations of the harness 8 for driving the injector. In addition, since the vibration of the harness 8 is suppressed, the fuel injection system 3 according to the present embodiment suppresses disconnection and deterioration at the connection part 81 of the harness 8, suppresses a decrease in the durability of the harness 8, and amplifies noise. You can refrain from doing that. Furthermore, the harness 8 is not a special part for fixing the harness, but is fixed to the bracket 5 that supports the fuel pressure accumulator 6. Therefore, the fuel injection system 3 according to the present embodiment can suppress the vibration of the harness 8 for driving the injector while suppressing an increase in the number of parts.

Further, the harness 8 is fixed to the bracket 5 at a position adjacent to a connecting portion 81 connected to the injector 7. Therefore, the portion where the harness 8 is fixed to the bracket 5 can support the harness 8 at a position near the connecting portion 81 between the harness 8 and the injector 7. Thereby, the fuel injection system 3 according to the present embodiment can further suppress vibrations of the harness 8 for driving the injector.

Further, the harness 8 extends along the arrangement direction A1 of the plurality of injectors 7, and is fixed to the bracket 5 at a position between the plurality of adjacent injectors 7. Therefore, the portion where the harness 8 is fixed to the bracket 5 is located near the connecting portion 81 between the harness 8 and the injector 7 among the harness 8 extending along the arrangement direction A1 of the plurality of injectors 7. can be supported. Thereby, the fuel injection system 3 according to the present embodiment can further suppress vibrations of the harness 8 for driving the injector.

Further, a holding member 82 that holds the harness 8 is attached to the bracket 5 to fix the harness 8 to the bracket 5. Therefore, the harness 8 is fixed to the bracket 5 more reliably and is fixed to the bracket 5 with a simple structure. Thereby, the fuel injection system 3 according to the present embodiment can securely fix the harness 8 to the bracket 5 using the holding member 82 while suppressing an increase in the number of parts, and can suppress vibrations of the harness 8.

FIG. 7 is a top view showing the arrangement relationship between the bracket and the cylinder head of this embodiment.
FIG. 8 is a top view showing the cylinder head of this embodiment.

As described above with respect to FIGS. 1 and 2, the bracket 5 is fixed to the upper part of the cylinder head 21 using a second fastening member 59. At this time, as shown in FIG. 7, the bracket 5 is placed on the upper part of the cylinder head 21, straddling the upper part of the combustion chamber 215 provided in the cylinder head 21. In the example shown in FIG. 7 , the second fixing portion 52 and the third reinforcing portion 543 of the bracket 5 straddle above the combustion chamber 215 provided in the cylinder head 21 . However, the part of the bracket 5 that straddles the combustion chamber 215 is not limited to the second fixing part 52 and the third reinforcing part 543.

As shown in FIG. 8, the cylinder head 21 has a mounting surface 216. The bracket 5 is placed on the mounting surface 216 of the cylinder head 21 and fixed to the cylinder head 21. As shown in FIG. 8, the mounting surface 216 is provided in a region spanning above the combustion chamber 215 provided in the cylinder head 21. For example, the combustion chamber 215 shown in FIGS. 7 and 8 is a subchamber (ie, a subcombustion chamber) formed inside the cylinder head 21.

Here, as described above with reference to FIGS. 1 to 6, the injector 7 is mounted on the upper part of the cylinder head 21. Further, the fuel pressure accumulator 6 and the fuel pipe 61 are provided at a position upwardly away from the cylinder head 21. Therefore, if the bracket 5 does not exist, a relatively large amount of space will exist above and above the cylinder head 21. In this case, combustion noise generated in the combustion chamber 215 may easily leak upward to the cylinder head 21.

On the other hand, according to the fuel injection system 3 according to the present embodiment, the bracket 5 supporting the fuel pressure accumulator 6 is placed on the upper part of the cylinder head 21 straddling the upper part of the combustion chamber 215 of the engine 2. and is fixed to the upper part of the cylinder head 21. In this way, since the bracket 5 is placed and fixed on the upper part of the cylinder head 21 while straddling the upper part of the combustion chamber 215 of the engine 2, the combustion noise generated in the combustion chamber 215 of the engine 2 is absorbed by the cylinder head. 21 can be prevented from leaking upward. Further, the bracket 5 supporting the fuel pressure accumulator 6 functions as a heavy object fixed to the upper part of the cylinder head 21, and exerts a damping effect in the portion fixed to the cylinder head 21. Therefore, the bracket 5 has a function of blocking combustion noise generated in the combustion chamber 215 of the engine 2, that is, a sound insulation function. Thereby, the fuel injection system 3 according to the present embodiment can reduce combustion noise generated in the combustion chamber 215 of the engine 2.

Further, when the combustion chamber 215 is a sub-chamber formed inside the cylinder head 21, the bracket 5 suppresses combustion noise generated in the sub-chamber from leaking above the cylinder head 21 directly above the sub-chamber. be able to. Further, the bracket 5 supporting the fuel pressure accumulator 6 functions as a heavy object fixed to the upper part of the cylinder head 21, and exerts a damping effect in the portion fixed to the cylinder head 21. Therefore, the bracket 5 has a function of blocking combustion noise generated in the subchamber, that is, a sound insulation function. As a result, when the combustion chamber 215 is a subchamber formed inside the cylinder head 21, the fuel injection system 3 according to the present embodiment can efficiently reduce combustion noise generated in the subchamber of the subchamber type engine. can be reduced.

Further, the cylinder head 21 has a mounting surface 216 on which the bracket 5 is mounted. Therefore, the fuel injection system 3 according to the present embodiment suppresses distortion in the bracket 5 when the bracket 5 is assembled and fixed to the cylinder head 21, and stabilizes the bracket 5 relative to the upper part of the cylinder head 21. It can be fixed. Furthermore, the fuel injection system 3 according to the present embodiment can improve the ease of assembling the bracket 5 to the upper part of the cylinder head 21. Furthermore, when the combustion chamber 215 is a pre-chamber formed inside the cylinder head 21, the mounting surface 216 of the cylinder head 21 extends above the pre-chamber provided in the cylinder head 21 of the pre-chamber type engine. It is provided in the straddling area. Therefore, the bracket 5 is stably placed on the mounting surface 216 provided in the region straddling the upper part of the sub-chamber while straddling the upper part of the sub-chamber, and is stably fixed to the upper part of the cylinder head 21. . Thereby, the bracket 5 can suppress vibrations caused by combustion in the subchamber from being transmitted above the cylinder head 21. As a result, when the combustion chamber 215 is an auxiliary chamber formed inside the cylinder head 21, the fuel injection system 3 according to the present embodiment suppresses combustion noise generated in the auxiliary chamber and vibrations caused by combustion in the auxiliary chamber. can be reduced.

FIG. 9 is a perspective view of the fuel accumulator according to the present embodiment, viewed diagonally from below.
Note that in FIG. 9, for convenience of explanation, the convex portion 64 that is press-fitted into the hole 63 and fixed is omitted.

As described above with reference to FIGS. 3 and 4, the protrusion 64 (not shown in FIG. 9) is press-fitted into the hole 63 of the fuel accumulator 6 and fixed. A fastening surface 631 is provided around the hole 63. The fastening surface 631 is a surface that comes into contact with the fastening surface 512 (see FIG. 4) of the bracket 5 when the fuel pressure accumulator 6 is fastened to the bracket 5 using the first fastening member 62.

Further, the injector 7 (not shown in FIG. 9) is inserted into the insertion hole 66 of the fuel pressure accumulator 6 and is directly connected to the fuel pressure accumulator 6. The end of the injector 7 is fluid-tightly inserted and held in the insertion hole 66 by, for example, an O-ring attached to the injector 7. Thereby, the injector 7 injects the fuel supplied through the insertion hole 66 of the fuel accumulator 6 into the combustion chamber 215. A positioning surface 661 is provided around the insertion hole 66. The positioning surface 661 is a surface that contacts the biasing member 72 attached to the injector 7 and determines the position of the injector 7.

As shown in FIG. 9, the fastening surface 631 formed around the hole 63 is flush with the positioning surface 661 formed around the insertion hole 66. As a result, the fuel injection system 3 according to the present embodiment can facilitate assembly, improve workability, and attach the fuel pressure accumulator 6 to which the injector 7 is directly connected to the bracket 5. Can be stably fixed.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the scope of the claims. A part of the configuration of the above embodiment may be omitted or may be arbitrarily combined in a manner different from that described above.

2: Engine, 3: Fuel injection system, 5: Bracket, 6: Fuel accumulator, 7: Injector, 8: Harness, 21: Cylinder head, 22: Head cover,
23: Intake manifold, 51: First fixing part, 52: Second fixing part, 53: Third fixing part, 59: Second fastening member, 61: Fuel pipe, 62: First fastening member, 63: Hole, 64 : Convex part, 66: Insertion hole, 71: Positioning surface, 72: Biasing member, 81: Connection part, 82: Holding member, 211: Sleeve, 212: Insertion hole, 213: Female screw, 214: Positioning surface, 215 : Combustion chamber, 216: Placement surface, 511: Female screw, 512: Fastening surface, 513: Recess, 521: Hole, 531: Hole, 541: First reinforcing section, 542: Second reinforcing section, 543: Third Reinforcement part, 631: Fastening surface, 641: Tip part, 661: Positioning surface, 821: Projection part, A1: Arrangement direction, D1, D2: Distance

Claims (5)

A fuel injection system that injects fuel into a combustion chamber of an engine,
a bracket fixed to the cylinder head of the engine;
a fuel accumulating device that is supported and fixed to the bracket using a fastening member and that accumulates pressure of the fuel supplied from the fuel pump;
an injector that is directly connected to the fuel pressure accumulator and is attached to the cylinder head and injects the fuel supplied from the fuel pressure accumulator into the combustion chamber;
Equipped with
At least one of the fuel pressure accumulator and the bracket includes a guide member that guides the injector to a mounting position of the cylinder head,
The guide member is
a convex portion provided on either one of the fuel pressure accumulator and the bracket;
a recess provided on the other of the fuel pressure accumulator and the bracket into which the protrusion fits;
has
The fuel injection system is characterized in that the convex portion is a hollow rod-shaped member that is fixed to either the fuel pressure accumulator or the bracket and has an inner diameter through which the fastening member can pass. The injector is attached to the cylinder head by being inserted into an insertion hole formed in the cylinder head,
2. The fuel injection system according to claim 1, wherein a direction in which the convex part fits into the concave part is parallel to a direction in which the injector is inserted into the insertion hole. The fuel injection system according to claim 1 or 2, wherein the guide member has a plurality of the protrusions and a plurality of the recesses into which each of the plurality of protrusions fits. Any one of claims 1 to 3, wherein when the injector is attached to the cylinder head, the convex part begins to fit into the concave part before the position of the injector with respect to the cylinder head is determined. Fuel injection system as described in. The fastening member is a first fastening member,
The bracket is fixed to the cylinder head using a second fastening member, and a first fastening part that engages with the first fastening member and a second fastening part having a hole through which the second fastening member passes are adjacent to each other. According to any one of claims 1 to 4, the reinforcing part connects and reinforces the first fixing part and the second fixing part, and is formed in a ladder shape or a lattice shape. Fuel injection system as described.

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