Fuel injection pump

Abstract

The fuel injection pump is light in weight, and rigidity for fixing the fuel injection pump to an installation part is ensured. A fuel injection pump according to the present invention is provided with: a main body section having a hole and a flange formed in the center section in the axial direction; a plunger cylinder disposed in contact with the main body portion and having a hole formed in the center portion in the axial direction; a plunger moving along the bore of the body portion and the bore of the plunger barrel; and a discharge valve facing the bore of the plunger barrel and opposed to the plunger, a fuel compression chamber being provided in the bore of the plunger barrel between a tip of the plunger and the discharge valve, the flange having a path through which fuel compressed in the fuel compression chamber passes, and the main body part is fixed at a setting part by a bolt penetrating through the flange.

Description

Technical Field

[0001] The invention relates to a fuel injection pump. Background Art

[0002] For example, a fuel injection pump for an internal combustion engine is disclosed in Patent Document 1. This fuel injection pump comprises a barrel disposed within a housing, and a plunger disposed within the barrel. Fuel is supplied to a pump chamber within the barrel via a fuel chamber provided in the housing, a fuel supply port provided in the barrel, and a barrel port provided in the barrel. The fuel supplied to the pump chamber within the barrel is pressurized by the rising plunger and discharged through an isobaric valve.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6807805

[0006] Technical problem to be solved by the invention

[0007] In the fuel injection pump disclosed in Patent Document 1, a rectangular flange is provided on the housing when viewed from above, and the four corners of the flange are fastened with bolts to secure the housing. In order to reduce the weight of the fuel injection pump, if the flange is made thinner, the rigidity for securing the fuel injection pump is insufficient. Summary of the Invention

[0008] The present invention has been made in view of the above-mentioned technical problems, and an object of the present invention is to reduce the weight of a fuel injection pump while ensuring the rigidity for fixing the fuel injection pump to the installation position.

[0009] Technical means for solving technical problems

[0010] In order to solve the above-mentioned technical problems and achieve the purpose, the fuel injection pump involved in the present invention has the following structure, comprising: a main body, which has a hole and a flange formed in the axial direction at the center; a plunger cylinder, which is arranged in contact with the main body and has a hole formed in the axial direction at the center; a plunger, which moves along the hole of the main body and the hole of the plunger cylinder; and a discharge valve, which faces the hole of the plunger cylinder and is opposite to the plunger, and a fuel compression chamber is provided in the hole of the plunger cylinder between the top end of the plunger and the discharge valve, the flange has a path for the fuel compressed in the fuel compression chamber to pass through, and the main body is fixed to the setting position by bolts passing through the flange.

[0011] In the present invention, the structure may also be as follows: the flange is arranged at a position where the area connected to the plunger cylinder is extended in a direction intersecting the axial direction, the path of the flange is open on the side of the flange, and the main body is fixed to the setting position by a bolt passing through a hole that penetrates the flange in the up and down directions.

[0012] In the present invention, the plunger may be connected to the fuel compression chamber and have a path through which the fuel passes.

[0013] In the present invention, the wall thickness of the plunger tube may be thicker than the diameter of the plunger in the radial direction of the fuel compression chamber.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to ensure rigidity for fixing the fuel injection pump to the installation location while reducing the weight of the fuel injection pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of a fuel injection device.

[0017] Figure 2 This is a perspective view of a fuel injection pump.

[0018] Figure 3 This is a front view of the fuel injection pump.

[0019] Figure 4 yes Figure 3 AA line section view.

[0020] Figure 5 It is a partial cross-sectional view of the fuel injection pump.

[0021] Figure 6 It is a top view of the fuel injection pump.

[0022] Figure 7 This is a perspective view of a flange connected to a fuel injection pump.

[0023] Figure 8 is a cross-sectional view of the plunger.

[0024] Explanation of symbols

[0025] 1 fuel injection valve

[0026] 2 fuel injection pumps

[0027] 3. Pressure accumulator control valve block

[0028] 10 Discharge valve cover

[0029] 20 Discharge valve seat cover

[0030] 21 discharge valve seat

[0031] 30 plunger barrel

[0032] 31 plunger hole

[0033] 32 fuel compression chamber

[0034] 40 main body

[0035] 41 flange

[0036] 42 fuel supply line

[0037] 43 fuel discharge path

[0038] 50 plungers

[0039] 60 boost cylinder

[0040] 61 boost piston

[0041] 1000 fuel injection unit. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the present invention is not limited to the embodiments described below. In addition, in the description of the accompanying drawings, the same symbols are appropriately marked for the same or corresponding elements. Furthermore, it should be noted that the accompanying drawings are schematic, and the relationship between the dimensions of the elements may be different from the actual elements. The accompanying drawings sometimes also contain parts with different dimensional relationships and ratios. In addition, the orthogonal coordinate system of the X-axis, Y-axis and Z-axis is appropriately represented in the drawings to illustrate the direction. In the space represented by the orthogonal coordinate system, the direction in which the X component increases is called the +X direction, and the direction in which the X component decreases is called the -X direction. Similarly, the Y and Z components are also defined as the +Y direction, -Y direction, +Z direction, and -Z direction. In addition, for the convenience of explanation, the +Z direction is sometimes referred to as the top, the -Z direction is sometimes referred to as the bottom, and the Z-axis direction is sometimes referred to as the up and down direction.

[0043] Figure 1 1 is a schematic diagram of a fuel injection device 1000 according to an embodiment of the present invention. The fuel injection device 1000 is mounted on a large marine diesel engine (internal combustion engine) mounted on a ship. The fuel injection device 1000 includes a fuel injection valve 1 , a fuel injection pump 2 , and a pressure accumulation control valve block 3 .

[0044] The fuel injection valve 1 is a valve that injects fuel (heavy oil C) into the combustion chamber of a diesel engine (not shown). The fuel injection pump 2 is a pump that pressurizes fuel to the fuel injection valve 1. The fuel injection pump 2 is mounted on a pressure accumulator control valve block 3. The fuel injection pump 2 is connected to the fuel injection valve 1 via a fuel pipe 4. The fuel pressurized by the fuel injection pump 2 is delivered to the fuel injection valve 1 via the fuel pipe 4. The pressure accumulator control valve block 3 drives the fuel injection pump 2 and is mounted on the side of the diesel engine cylinder block, etc.

[0045] Hereinafter, the fuel injection pump 2 according to the present invention will be described. Figure 2 is a perspective view of the fuel injection pump 2. Figure 3 is a front view of the fuel injection pump 2, Figure 4 yes Figure 3 AA line section view. In addition, Figure 5 is a rear view of the fuel injection pump 2, Figure 6 2 is a top view of the fuel injection pump 2. Figure 2 As shown, the fuel injection pump 2 includes a discharge valve cover 10 , a discharge valve seat cover 20 , a plunger tube 30 , a main body 40 , and a booster cylinder 60 .

[0046] like Figure 4 As shown, the lower end of the discharge valve cover 10 is connected to the upper end of the discharge valve seat cover 20 and the upper end of the discharge valve seat 21. The discharge valve cover 10 is formed with bolt holes 19 that penetrate in the vertical direction near the outer periphery. The discharge valve cover 10 is fixed to the discharge valve seat cover 20 by bolts 16 inserted into the bolt holes 19. The discharge valve cover 10 is formed with a fuel discharge path 15 and a discharge valve receiving portion 14 in the radial center portion of the discharge valve cover 10. In addition, as shown in FIG. Figure 5 As shown, the discharge valve cover 10 is formed with bolt holes 18 extending vertically near the outer periphery. The fuel discharge path 15 is open on the upper end side of the discharge valve cover 10. The fuel piping 4 is connected to the upper end of the discharge valve cover 10, and the fuel discharged from the fuel discharge path 15 is sent to the fuel injection valve 1 through the fuel piping 4. The discharge valve spring bracket 11 is a spring bracket that supports the discharge valve spring 12 and is arranged at the upper part of the discharge valve housing 14. The fuel passage 11a connecting the discharge valve spring bracket 11 and the fuel discharge path 15 is formed in the radial center of the discharge valve cover 10 along the vertical direction. The discharge valve spring 12 is a spring that presses the discharge valve 13 downward. The discharge valve spring 12 is housed in the discharge valve housing 14, with the upper end connected to the discharge valve spring bracket 11 and the lower end connected to the discharge valve 13.

[0047] The discharge valve seat cover 20 is cylindrical and is disposed on the plunger tube 30. The discharge valve seat 21 is disposed inside the discharge valve seat cover 20. The upper end of the discharge valve seat 21 is connected to the discharge valve cover 10, and the lower end is connected to the plunger tube 30. Figure 5As shown, the discharge valve seat cover 20 has bolt holes 23 extending vertically through it near its outer periphery. The discharge valve seat 21 receives the discharge valve 13. A vertical fuel passage 22 is formed in the radial center of the discharge valve seat cover 20. The discharge valve 13 has a small diameter portion and a large diameter portion. The small diameter portion is located within the fuel passage 22, while the large diameter portion protrudes toward the discharge valve housing 14. The discharge valve 13 is vertically movable, with the large diameter portion being pressed against the discharge valve seat 21 by the discharge valve spring 12.

[0048] The plunger tube 30 is cylindrical and is disposed on the main body 40. Figure 5 As shown, the plunger tube 30 has a bolt hole 38 extending vertically near its outer periphery. Furthermore, the plunger hole 31 of the plunger tube 30, into which the plunger 50 is inserted, is formed in the radial center portion of the plunger tube 30 along the vertical direction (axial direction). The plunger tube 30 has an upper tapered portion 33 formed at the top for insertion into the discharge valve seat cover 20, and a lower tapered portion 34 formed at the bottom for insertion into the main body 40. A supply path 36 extending from the inner circumference to the outer circumference is formed on the +Y direction side of the lower tapered portion 34, while a discharge path 37 extending from the inner circumference to the outer circumference is formed on the -Y direction side. The supply path 36 is a path through which the fuel pressure-fed to the fuel injection valve 1 flows to the plunger hole 31, and the discharge path 37 is a path through which the fuel discharged from the plunger hole 31 flows. In the plunger hole 31, the space between the upper end of the plunger 50 and the lower end of the discharge valve seat 21 and the discharge valve 13 forms a fuel compression chamber 32, where fuel supplied from the supply passage 36 is compressed by the plunger 50. A large-diameter portion 35, which houses the fuel compression chamber 32, is located at the radial center of the plunger tube 30 between the upper and lower small-diameter portions 33 and 34. This portion is located outside the main body 40 and above its upper end. The outer diameter of this large-diameter portion 35 is larger than that of the upper and lower small-diameter portions 33 and 34. In the radial direction of the fuel compression chamber 32, the wall thickness of this large-diameter portion 35, which is the difference between the radius of the plunger hole 31 and the radius of the large-diameter portion 35, is greater than the diameter of the plunger hole 31.

[0049] The main body 40 has a flange 41 at the upper portion. Figure 4 As shown, a small diameter hole 46 along the vertical direction (axial direction) and a large diameter hole 47 with a larger diameter than the small diameter hole 46 are formed in the center portion in the X-axis direction and the Y-axis direction, and the small diameter hole 46 is formed above the large diameter hole 47. Figure 2As shown, the flange 41 as an example of a fixed flange is provided in a portion extending the area connected to the plunger tube 30 on the +Z direction side in a direction intersecting the central axis of the narrow-diameter hole 46, and the width in the Y-axis direction is formed to be wider than the width in the X-axis direction, and the width in the X-axis direction is formed to be wider than the outer diameter of the plunger tube 30. In the flange 41, a fuel supply path 42 and four bolt holes 44 are formed on the side surface on the -Y direction side, and a fuel discharge path 43 and four bolt holes 44 are formed on the side surface on the +Y direction side. The side surface on the -Y direction side and the side surface on the +Y direction side of the flange 41 are examples of connection surfaces to which piping for fuel to pass is connected. In addition, as Figure 5 As shown, the flange 41 is formed with bolt holes 48 in the vertical direction at the position where it contacts the plunger tube 30. By inserting the bolts 17 that have passed through the bolt holes 18, 23, and 38 into the bolt holes 48 and tightening them, the discharge valve cover 10, the discharge valve seat cover 20, the plunger tube 30, and the body 40 are integrated. Figure 6 As shown, four bolt holes 45 are formed at four corners of the flange 41. The main body 40 is fixed to the pressure accumulation control valve block 3 as an example of the installation location by bolts passing through the bolt holes 45.

[0050] The fuel supply passage 42 extends from the side surface on the -Y direction side of the flange 41 to the small-diameter hole 46, and the fuel discharge passage 43 extends from the side surface on the +Y direction side of the flange 41 to the small-diameter hole 46. The fuel supply passage 42 is connected to the supply passage 36 of the plunger cylinder 30, and the fuel discharge passage 43 is connected to the discharge passage 37 of the plunger cylinder 30. A pipe for supplying fuel is connected to the fuel supply passage 42, and a pipe for passing fuel discharged from the fuel injection pump 2 is connected to the fuel discharge passage 43.

[0051] Figure 7 This is a three-dimensional view of the flange 80 connected to the side surface on the -Y direction side of the flange 41. The flange 80 is an example of a connecting flange. In addition, the flange 80 is also connected to the side surface on the +Y direction side of the flange 41. Bolts 82 are inserted into the bolt holes 44 to fix the flange 80 to the flange 41. The fuel piping 81 is connected to the fuel supply path 42 through the flange 80 fixed to the side surface on the -Y direction side of the flange 41, and the fuel flows from the fuel piping 81 to the fuel supply path 42. In addition, the fuel piping 81 is connected to the fuel discharge path 43 through the flange 80 fixed to the side surface on the +Y direction side of the flange 41, and the fuel discharged from the fuel supply path 42 flows to the fuel piping 81. The fuel piping 81 is a piping through which the fuel that is pressurized and fed to the fuel injection valve 1 flows. The fuel piping 81 is connected to a circulation path that heats the fuel and circulates the fuel. The circulation path is provided with a pump for circulating the fuel. The heated fuel is pumped to the fuel supply path 42 by the pump. The fuel discharged from the fuel discharge path 43 is stored in a tank via the circulation path and is pumped again to the fuel supply path 42 by the pump.

[0052] The lower, thin-diameter portion 34 of the plunger tube 30 is inserted into the thin-diameter hole 46 of the main body 40, and the booster cylinder 60 is inserted into the lower portion of the thick-diameter hole 47. Furthermore, the thick-diameter hole 47 contains the plunger 50, a plunger spring 51, and a plunger spring holder 52. The plunger spring holder 52 supports the plunger spring 51. Its radial center extends vertically, and the lower end of the plunger 50 is inserted into the vertically extending center portion of the through-hole. The plunger spring 51 presses the plunger spring holder 52 downward. Its upper end is connected to the upper end of the thick-diameter hole 47, and its lower end is connected to the plunger spring holder 52.

[0053] The lower portion of the plunger 50 is embedded in the plunger spring bracket 52 , and the upper portion is inserted into the plunger hole 31 of the plunger cylinder 30 . Figure 8 This is a cross-sectional view of the plunger 50. A fuel supply path 50a, a fuel discharge path 50b, and a fuel path 50c are formed on the upper portion of the plunger 50. Furthermore, an intake valve 70, an intake valve spring 71, an upper spring support 72, and a lower spring support 73 are arranged above the radial center of the plunger 50. The upper spring support 72 and the lower spring support 73 serve as spring seats that support the intake valve spring 71. The intake valve spring 71 presses the lower spring support 73 downward, with its upper end connected to the upper spring support 72 and its lower end connected to the lower spring support 73. The lower spring support 73 is inserted into the lower end of the intake valve 70 and is pressed downward by the intake valve spring 71. The fuel supply path 50a is connected to the supply path 36 via an oil reservoir provided on the outer periphery of the plunger 50, while the fuel discharge path 50b is connected to the discharge path 37 via an oil reservoir provided on the outer periphery of the plunger 50.

[0054] The intake valve 70 is movable in the vertical direction, with its upper portion positioned in the fuel passage 50c. When the plunger 50 ascends, causing the pressure within the fuel compression chamber 32 to exceed the pressure of the fuel supplied to the fuel supply passage 50a, the upper end of the intake valve 70 contacts the opening on the +Z side of the fuel passage 50c, thereby blocking the gap between the fuel compression chamber 32 and the fuel passage 50c. Furthermore, when the plunger 50 descends, causing the pressure within the fuel compression chamber 32 to fall below the pressure of the fuel supplied to the fuel supply passage 50a, the intake valve 70 moves upward, and the upper end of the intake valve 70 moves away from the opening on the +Z side of the fuel passage 50c. This connects the fuel compression chamber 32 and the fuel passage 50c, allowing fuel to be supplied to the fuel compression chamber 32.

[0055] The smaller upper portion of the booster cylinder 60 is inserted into the larger hole 47. The upper end of the larger lower portion is connected to the lower end of the main body 40, and the lower end is connected to and fixed to the pressure accumulator control valve block 3. A piston hole 62 is formed in the radial center of the booster cylinder 60 for inserting a booster piston 61. The booster piston 61 is the piston that raises the plunger 50. The booster piston 61 is inserted into the piston hole 62, with its upper end contacting the lower end of the plunger 50. The booster piston 61 is driven by the pressure accumulator control valve block 3 to raise the plunger 50.

[0056] Next, the operation of the fuel injection pump 2 will be described. When the pump, located in the fuel circulation path, delivers fuel at a predetermined pressure, fuel is supplied from the fuel pipe 81 through the fuel supply path 42, the supply path 36, and the fuel supply path 50a to the fuel passage 50c. This causes the intake valve 70, which is pressed downward by the intake valve spring 71, to move upward. When the intake valve 70 moves upward, the fuel passage 50c is connected to the fuel compression chamber 32, and the supplied fuel is delivered to the fuel compression chamber 32.

[0057] While fuel is being supplied to the fuel compression chamber 32, when the booster piston 61 ascends through the pressure accumulator control valve block 3, the plunger 50, pressed by the booster piston 61, ascends, compressing the fuel supplied to the fuel compression chamber 32. When the pressure of the fuel applied to the fuel compression chamber 32 exceeds a predetermined pressure due to the ascending plunger 50, the discharge valve 13 ascends, connecting the fuel compression chamber 32 to the discharge valve housing 14, and fuel flows from the fuel compression chamber 32 into the discharge valve housing 14. The fuel flowing into the discharge valve housing 14 is discharged into the fuel pipe 4 through the fuel passage 11a and the fuel discharge passage 15. The fuel discharged into the fuel pipe 4 is injected from the fuel injection valve 1 into the combustion chamber of the diesel engine.

[0058] When the fuel is discharged from the fuel discharge passage 15 and the pressure-accumulating control valve block 3 causes the boosting piston 61 to descend, the plunger spring 51 presses the plunger spring holder 52 downward, and the plunger 50 fitted into the plunger spring holder 52 descends.

[0059] In this embodiment, the large-diameter portion 35 of the plunger tube 30, which forms the fuel compression chamber 32, is located above the main body 40 and is not housed within the main body 40. Therefore, even if the fuel injection pump 2 is miniaturized, the wall thickness of the plunger tube 30, which is the difference between the radius of the plunger hole 31 and the radius of the large-diameter portion 35, can be increased. This increased wall thickness of the plunger tube 30 reduces expansion of the plunger hole 31 during fuel compression, suppressing fuel leakage from the gap between the plunger 50 and the plunger hole 31. This allows for efficient fuel compression and delivery to the fuel injection valve 1. Furthermore, in this embodiment, the large-diameter portion 35 of the plunger tube 30 is not incorporated into other components. Therefore, even if the plunger tube 30 is miniaturized by reducing its diameter, sufficient wall thickness can be maintained for efficient fuel compression.

[0060] Furthermore, in this embodiment, the flange 41 used to secure the fuel injection pump 2 to the pressure accumulator control valve block 3 is thickened in the vertical direction and widened in the Y-axis direction to form the fuel supply path 42 and fuel discharge path 43. This increases rigidity and reduces deformation in the -Z direction from the bolts 17 when tightening the bolt holes 45. Furthermore, because the flange 41 also serves as a connection for the fuel pipe 81, compared to a structure in which separate flanges are provided for connecting the fuel pipe 81 and for securing the fuel injection pump 2 to the pressure accumulator control valve block 3, the volume of the fuel injection pump 2 can be reduced while maintaining the rigidity of the flange 41 for securing the fuel pipe 81. Furthermore, in this embodiment, since the flange 41 is formed on the main body 40, the +Y and -Y side surfaces of the flange 41 to which the flange 80 is attached can be enlarged. This allows connection to a fuel pipe 81 with a larger diameter, thus preventing fuel supply shortages to the fuel compression chamber 32 even with reduced size.

[0061] [Modification]

[0062] The embodiments of the present invention have been described above, but the present invention is not limited to the above-mentioned embodiments and can be implemented in various other ways. For example, the above-mentioned embodiments can also be modified as follows to implement the present invention. In addition, the above-mentioned embodiments and the following modifications can also be combined respectively. Structures formed by appropriately combining the constituent elements of the above-mentioned embodiments and modifications are also included in the present invention. In addition, those skilled in the art can easily derive further effects and modifications. Therefore, the broader aspects of the present invention are not limited to the above-mentioned embodiments and modifications and can be variously modified.

[0063] In the above embodiment, the plunger tube 30 has the lower tapered portion 34, but a configuration without the lower tapered portion 34 is also possible. In this modified example, the plunger tube 30 is partially not inserted into the main body 40. In this modified example, the fuel supply path 42 is connected to the fuel supply path 50a, and the fuel discharge path 43 is connected to the fuel discharge path 50b.

[0064] In the above-described embodiment, the outer diameter of the large-diameter portion 35 is smaller than the width of the main body 40 . However, the outer diameter of the large-diameter portion 35 may be larger than the width of the main body 40 .

Claims

1. A fuel injection pump, characterized in that: have: a main body portion having a hole and a flange formed in an axial direction at a center portion thereof; a plunger cylinder, the plunger cylinder being arranged in contact with the main body and having a hole formed in the axial direction at the center thereof; a plunger that moves along the hole of the main body and the hole of the plunger barrel; as well as a discharge valve facing the hole of the plunger barrel and opposite to the plunger, A fuel compression chamber is provided in the hole of the plunger cylinder between the top end of the plunger and the discharge valve, and the flange has a path for the fuel compressed in the fuel compression chamber to pass through. The main body is fixed to the installation position by bolts passing through the flange.

2. The fuel injection pump according to claim 1, characterized in that The flange is provided at a portion where the region in contact with the plunger tube is extended in a direction intersecting the axial direction, and the path of the flange is open at a side surface of the flange. The main body is fixed to the installation location by bolts passing through holes that pass through the flange in the up-down direction.

3. The fuel injection pump according to claim 1, characterized in that The plunger is connected to the fuel compression chamber and has a path for the fuel to pass through.

4. The fuel injection pump according to claim 1, characterized in that In a radial direction of the fuel compression chamber, a wall thickness of the plunger cylinder is thicker than a diameter of the plunger.

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