Fuel injection pump

Abstract

To secure rigidity for fixation to an installation site while reducing weight of a fuel injection pump.SOLUTION: A fuel injection pump includes: a body part of which central part has a hole formed in the axial direction and a flange; a plunger barrel that is disposed to come into contact with the body part and of which a central part has a hole formed in the axial direction; a plunger that moves along the hole of the body part and the hole of the plunger barrel; and a discharge valve facing the hole of the plunger barrel and opposed to the plunger. A fuel compression chamber is provided between a tip of the plunger and the discharge valve in the hole of the plunger barrel. The flange has a path in which fuel to be compressed in the fuel compression chamber passes, and the body part is fixed to an installation site by a bolt passing through the flange.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] One example of a fuel injection pump used in an internal combustion engine is the fuel injection pump disclosed in Patent Document 1. This fuel injection pump has a barrel disposed in a housing, and a plunger disposed in the barrel. Fuel is supplied to a pump chamber in the barrel through 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 in the barrel is pressurized by the raised plunger and discharged from a pressure equalizing valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6807805 Summary of the Invention [Problem to be solved by the invention]

[0004] The fuel injection pump disclosed in Patent Document 1 has a rectangular flange when viewed from above the housing, and is fixed to the installation location by fastening the four corners of this flange with bolts. If the flange is made thinner in order to reduce the weight of the fuel injection pump, the rigidity required to fix the fuel injection pump will be insufficient.

[0005] The present invention has been made in view of the above, and has an object to reduce the weight of a fuel injection pump while ensuring the rigidity required for fixing the pump to an installation location. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the fuel injection pump of the present invention comprises: a main body having a flange and a hole formed axially in the center; a plunger barrel arranged in contact with the main body and having a hole formed axially in the center; a plunger that moves along the hole in the main body and the hole in the plunger barrel; and a discharge valve that faces the hole in the plunger barrel and faces the plunger, wherein a fuel compression chamber is provided in the hole in the plunger barrel between the tip of the plunger and the discharge valve, the flange has a path through which fuel compressed in the fuel compression chamber passes, and the main body is configured to be fixed to an installation location by bolts that are passed through the flange.

[0007] In the present invention, the flange may be provided in a portion extending from the area in contact with the plunger barrel in a direction intersecting the axial direction, the path of the flange may open to a side of the flange, and the main body portion may be configured to be fixed to the installation location by a bolt passed through a hole that penetrates the flange in the vertical direction.

[0008] In the present invention, the plunger may have a path that is connected to the fuel compression chamber and through which the fuel passes.

[0009] In the present invention, the plunger barrel may have a wall thickness greater than a diameter of the plunger in a radial direction of the fuel compression chamber. [Effects of the Invention]

[0010] According to the present invention, it is possible to reduce the weight of the fuel injection pump while ensuring the rigidity required for fixing it to an installation location. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a fuel injection system. [Figure 2] FIG. 2 is a perspective view of the fuel injection pump. [Figure 3]FIG. 3 is a front view of the fuel injection pump. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 5] FIG. 5 is a partial cross-sectional view of the fuel injection pump. [Figure 6] FIG. 6 is a plan view of the fuel injection pump. [Figure 7] FIG. 7 is a perspective view of a flange connected to a fuel injection pump. [Figure 8] FIG. 8 is a cross-sectional view of the plunger. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below. In addition, in the drawings, identical or corresponding elements are appropriately designated by the same reference numerals. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationships between elements may differ from those in reality. The drawings may also include portions with different dimensional relationships and ratios. Furthermore, a Cartesian coordinate system of X, Y, and Z axes is appropriately shown in the drawings, and directions are explained using this. In the space represented by the Cartesian 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 defined as the +Y direction, -Y direction, +Z direction, and -Z direction. Note that for convenience of explanation, the +Z direction is referred to as upward, the -Z direction is referred to as downward, and the Z axis direction may be referred to as the up-down direction.

[0013] 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 an accumulator control valve block 3.

[0014] Fuel injection valve 1 is a valve that injects fuel (heavy oil C) into the combustion chamber of a diesel engine (not shown), and fuel injection pump 2 is a pump that pressure-feeds fuel to fuel injection valve 1. Fuel injection pump 2 is provided on top of accumulator control valve block 3. Fuel injection pump 2 is connected to fuel injection valve 1 via fuel piping 4, and the fuel pressure-feed by fuel injection pump 2 is sent to fuel injection valve 1 through fuel piping 4. Accumulator control valve block 3 drives fuel injection pump 2, and is provided on the side of the cylinder block of the diesel engine, for example.

[0015] The fuel injection pump 2 according to the present invention will now be described. Fig. 2 is a perspective view of the fuel injection pump 2, Fig. 3 is a front view of the fuel injection pump 2, and Fig. 4 is a cross-sectional view taken along line AA in Fig. 3. Fig. 5 is a rear view of the fuel injection pump 2, and Fig. 6 is a plan view of the fuel injection pump 2. As shown in Fig. 2, the fuel injection pump 2 has a discharge valve cover 10, a discharge valve seat cover 20, a plunger barrel 30, a main body 40, and a booster cylinder 60.

[0016] As shown in FIG. 4 , the lower end of the discharge valve cover 10 is in contact with 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 has bolt holes 19 formed near its outer periphery, penetrating in the vertical direction, and is fixed to the discharge valve seat cover 20 by bolts 16 inserted into the bolt holes 19. The discharge valve cover 10 has a fuel discharge passage 15 extending in the vertical direction and a discharge valve accommodating portion 14 formed in the radial center of the discharge valve cover 10. Furthermore, as shown in FIG. 5 , the discharge valve cover 10 has bolt holes 18 formed near its outer periphery, penetrating in the vertical direction. The fuel discharge passage 15 opens at the upper end of the discharge valve cover 10. A fuel pipe 4 is connected to the upper end of the discharge valve cover 10, and fuel discharged from the fuel discharge passage 15 is sent to the fuel injection valve 1 through the fuel pipe 4. The discharge valve spring retainer 11 is a spring retainer that receives the discharge valve spring 12 and is located above the discharge valve accommodating portion 14. The discharge valve spring retainer 11 has a fuel passage 11a that is connected to a fuel discharge path 15 and that extends vertically in the radial center of the discharge valve cover 10. The discharge valve spring 12 is a spring that presses the discharge valve 13 downward. The discharge valve spring 12 is housed in a discharge valve housing portion 14, with its upper end contacting the discharge valve spring retainer 11 and its lower end contacting the discharge valve 13.

[0017] The discharge valve seat cover 20 is cylindrical and is disposed on the plunger barrel 30. The discharge valve seat 21 is disposed inside the discharge valve seat cover 20, with its upper end contacting the discharge valve cover 10 and its lower end contacting the plunger barrel 30. As shown in FIG. 5 , the discharge valve seat cover 20 has bolt holes 23 formed in the vicinity of its outer periphery, penetrating in the vertical direction. The discharge valve seat 21 is a valve seat that receives the discharge valve 13, and a fuel passage 22 extending in the vertical direction 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, with the small diameter portion positioned within the fuel passage 22 and the large diameter portion protruding into the discharge valve accommodating portion 14. The discharge valve 13 is movable in the vertical direction, and the large diameter portion is pressed against the discharge valve seat 21 by a discharge valve spring 12.

[0018] The plunger barrel 30 has a cylindrical shape and is disposed on the main body 40. As shown in FIG. 5 , the plunger barrel 30 has a bolt hole 38 formed near the outer periphery, penetrating in the vertical direction. The plunger barrel 30 also has a plunger hole 31 formed in the vertical (axial) direction at the radial center of the plunger barrel 30, into which the plunger 50 is inserted. The plunger barrel 30 has an upper narrow-diameter section 33 formed at its upper portion, which is inserted into the discharge valve seat cover 20, and a lower narrow-diameter section 34 formed at its lower portion, which is inserted into the main body 40. The lower narrow-diameter section 34 has a supply passage 36 formed on the +Y direction side, penetrating from the inner circumferential surface to the outer circumferential surface, and a discharge passage 37 formed on the -Y direction side, penetrating from the inner circumferential surface to the outer circumferential surface. The supply passage 36 is a passage through which fuel pressure-fed to the fuel injection valve 1 flows to the plunger hole 31, and the discharge passage 37 is a passage through which fuel discharged from the plunger hole 31 flows. The space in plunger bore 31 between the upper end of plunger 50 and the lower end of discharge valve seat 21 and discharge valve 13 is fuel compression chamber 32 in which fuel supplied from supply passage 36 is compressed by plunger 50. Large diameter portion 35, which is located between upper narrow diameter portion 33 and lower narrow diameter portion 34 and in which fuel compression chamber 32 is provided at the radial center of plunger barrel 30, is located outside main body 40 and above the upper end of main body 40, and has a larger outer diameter than upper narrow diameter portion 33 and lower narrow diameter portion 34. The thickness of large diameter portion 35, which is the difference between the radius of plunger bore 31 and the radius of large diameter portion 35, is thicker than the diameter of plunger bore 31 in the radial direction of fuel compression chamber 32.

[0019] The main body 40 has a flange 41 on its upper part. As shown in FIG. 4 , a small diameter hole 46 extending in the vertical direction (axial direction) and a large diameter hole 47 having a larger diameter than the small diameter hole 46 are formed in the center portions in the X-axis and Y-axis directions, with the small diameter hole 46 being formed above the large diameter hole 47. As shown in FIG. 2 , the flange 41, which is an example of a fixing flange, is provided on a portion extending from the region where the plunger barrel 30 contacts the +Z direction side in a direction intersecting the central axis of the small diameter hole 46. The flange 41 has a width in the Y-axis direction that is wider than the width in the X-axis direction and is also wider than the outer diameter of the plunger barrel 30. A fuel supply passage 42 and four bolt holes 44 are formed on the side surface on the -Y direction side of the flange 41, and a fuel discharge passage 43 and four bolt holes 44 are formed on the side surface on the +Y direction side. The -Y direction side and the +Y direction side of the flange 41 are examples of connection surfaces to which piping through which fuel passes is connected. 5, the flange 41 has bolt holes 48 formed in the vertical direction at positions where the plunger barrel 30 comes into contact. Bolts 17 passed through the bolt holes 18, 23, and 38 are inserted into the bolt holes 48 and tightened, thereby integrating the discharge valve cover 10, the discharge valve seat cover 20, the plunger barrel 30, and the main body 40. Further, the flange 41 has four bolt holes 45 formed in its four corners, each penetrating the flange 41 in the vertical direction, as shown in FIG. 6. The main body 40 is fixed to the pressure accumulator control valve block 3, which is an example of an installation location, by bolts passed through the bolt holes 45.

[0020] Fuel supply passage 42 penetrates from the side surface of flange 41 on the -Y direction side to small diameter hole 46, and fuel discharge passage 43 penetrates from the side surface of flange 41 on the +Y direction side to small diameter hole 46. Fuel supply passage 42 is connected to supply passage 36 of plunger barrel 30, and fuel discharge passage 43 is connected to discharge passage 37 of plunger barrel 30. A pipe that supplies fuel is connected to fuel supply passage 42, and a pipe through which fuel discharged from fuel injection pump 2 passes is connected to fuel discharge passage 43.

[0021] FIG. 7 is a perspective view of flange 80 connected to a side surface of flange 41 on the -Y direction side. Flange 80 is an example of a connecting flange. Note that flange 80 is also connected to a side surface of flange 41 on the +Y direction side. Bolts 82 are inserted into bolt holes 44 to fix flange 80 to flange 41. Fuel pipe 81 is connected to fuel supply path 42 by flange 80 fixed to the side surface of flange 41 on the -Y direction side, and fuel flows from fuel pipe 81 to fuel supply path 42. Fuel pipe 81 is also connected to fuel discharge path 43 by flange 80 fixed to the side surface of flange 41 on the +Y direction side, and fuel discharged from fuel supply path 42 flows to fuel pipe 81. Fuel pipe 81 is a pipe through which fuel to be pumped to fuel injection valve 1 flows. Fuel pipe 81 is connected to a circulation path that heats and circulates fuel. A pump for circulating the fuel is provided in the circulation path, and the heated fuel is sent 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 then sent again to the fuel supply path 42 by the pump.

[0022] The lower small diameter portion 34 of the plunger barrel 30 is inserted into the small diameter hole 46 of the main body 40, and a booster cylinder 60 is inserted into the lower part of the large diameter hole 47. Furthermore, a plunger 50, a plunger spring 51, and a plunger spring retainer 52 are disposed in the large diameter hole 47. The plunger spring retainer 52 is a spring retainer that receives the plunger spring 51, and its radial center portion is penetrated vertically, and the lower end of the plunger 50 is fitted into this penetrated center portion. The plunger spring 51 is a spring that presses the plunger spring retainer 52 downward, and its upper end contacts the upper end of the large diameter hole 47 and its lower end contacts the plunger spring retainer 52.

[0023] The plunger 50 has its lower portion fitted into the plunger spring retainer 52, and its upper portion inserted into the plunger bore 31 of the plunger barrel 30. FIG. 8 is a cross-sectional view of the plunger 50. A fuel supply passage 50a, a fuel discharge passage 50b, and a fuel passage 50c are formed in the upper portion of the plunger 50. Also, an intake valve 70, an intake valve spring 71, an upper spring retainer 72, and a lower spring retainer 73 are disposed above the radial center of the plunger 50. The upper spring retainer 72 and the lower spring retainer 73 are springs that retain the intake valve spring 71. The intake valve spring 71 presses the lower spring retainer 73 downward, with its upper end contacting the upper spring retainer 72 and its lower end contacting the lower spring retainer 73. The lower end of the intake valve 70 is fitted into the lower spring retainer 73, and the lower spring retainer 73 presses the intake valve spring 71 downward. The fuel supply passage 50a is connected to the supply passage 36 via an oil reservoir provided on the outer periphery of the plunger 50, and the fuel discharge passage 50b is connected to the discharge passage 37 via an oil reservoir provided on the outer periphery of the plunger 50.

[0024] Intake valve 70 is movable in the vertical direction, with its upper portion positioned in fuel passage 50c. When plunger 50 rises and the pressure in fuel compression chamber 32 exceeds the supply pressure of fuel supplied to fuel supply passage 50a, the upper end of intake valve 70 comes into contact with the opening of fuel passage 50c on the +Z direction side, thereby blocking the connection between fuel compression chamber 32 and fuel passage 50c. When plunger 50 descends and the pressure in fuel compression chamber 32 falls below the supply pressure of fuel supplied to fuel supply passage 50a, intake valve 70 moves upward and the upper end of intake valve 70 moves away from the opening of fuel passage 50c on the +Z direction side, thereby connecting fuel compression chamber 32 and fuel passage 50c, and fuel is supplied to fuel compression chamber 32.

[0025] The booster cylinder 60 has its narrow-diameter upper portion inserted into the large-diameter hole 47, its wide-diameter lower portion having an upper end in contact with the lower end of the main body 40, and its lower end in contact with and fixed to the pressure-accumulator control valve block 3. A piston hole 62 into which a booster piston 61 is inserted is formed in the radial center of the booster cylinder 60. The booster piston 61 is a piston that raises the plunger 50. The booster piston 61 is inserted into the piston hole 62, and its upper end is in contact with the lower end of the plunger 50, and is driven by the pressure-accumulator control valve block 3 to raise the plunger 50.

[0026] Next, the operation of fuel injection pump 2 will be described. When a pump in the fuel circulation path delivers fuel at a predetermined pressure, fuel is supplied from fuel pipe 81 through fuel supply path 42, supply path 36, and fuel supply path 50a to fuel passage 50c, causing intake valve 70, which is pressed downward by intake valve spring 71, to move upward. When intake valve 70 moves upward, fuel passage 50c and fuel compression chamber 32 are connected, and the supplied fuel is sent to fuel compression chamber 32.

[0027] When the booster piston 61 is raised by the pressure accumulator control valve block 3 while fuel is being supplied to the fuel compression chamber 32, the plunger 50, which is pushed by the booster piston 61, also rises, compressing the fuel supplied to the fuel compression chamber 32. When the pressure on the fuel in the fuel compression chamber 32 exceeds a predetermined pressure due to the rise of the plunger 50, the discharge valve 13 rises, connecting the fuel compression chamber 32 with the discharge valve housing 14, and fuel flows from the fuel compression chamber 32 to the discharge valve housing 14. The fuel that has flowed to the discharge valve housing 14 is discharged into the fuel pipe 4 through the fuel passage 11a and the fuel discharge path 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.

[0028] After fuel is discharged from the fuel discharge passage 15, when the booster piston 61 is lowered by the pressure accumulation control valve block 3, the plunger spring 51 presses the plunger spring receiver 52 downward, and the plunger 50 fitted in the plunger spring receiver 52 descends.

[0029] In this embodiment, the large diameter portion 35 of the plunger barrel 30, in which the fuel compression chamber 32 is formed, is located above the main body 40 and is not housed within the main body 40. This allows the thickness of the plunger barrel 30, which is the difference between the radius of the plunger bore 31 and the radius of the large diameter portion 35, to be increased even when the fuel injection pump 2 is downsized. Because the thickness of the plunger barrel 30 can be increased in this manner, the expansion of the plunger bore 31 during fuel compression is reduced, preventing fuel leakage from the gap between the plunger 50 and the plunger bore 31, and enabling the fuel to be efficiently compressed and sent to the fuel injection valve 1. Furthermore, in this embodiment, the large diameter portion 35 of the plunger barrel 30 is not incorporated into another component, so a wall thickness sufficient for efficient fuel compression can be ensured even when the plunger barrel 30 is downsized by reducing the diameter of the plunger barrel 30.

[0030] Furthermore, in this embodiment, the flange 41 for fixing the fuel injection pump 2 to the accumulator control valve block 3 is thick in the vertical direction and wide in the Y-axis direction to form the fuel supply passage 42 and the fuel discharge passage 43, and therefore has high rigidity and is less deformed by a force in the −Z direction from the bolt 17 when the bolt 17 is tightened through the bolt hole 45. Furthermore, since the flange 41 also serves as a connecting portion for the fuel pipe 81, compared to a configuration in which a flange for connecting the fuel pipe 81 and a flange for fixing the fuel injection pump 2 to the accumulator control valve block 3 are separately provided, the volume of the fuel injection pump 2 can be reduced and made more compact while ensuring the rigidity of the flange 41 for fixing to the accumulator control valve block 3. Furthermore, in this embodiment, since the flange 41 is formed on the main body 40, the side surface on the +Y direction side and the side surface on the −Y direction side of the flange 41 to which the flange 80 is attached can be made wider, and therefore a fuel pipe 81 with a large diameter can be connected, and a shortage of fuel supplied to the fuel compression chamber 32 can be prevented even when the size is reduced.

[0031] [Variations] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be implemented in various other forms. For example, the above-described embodiments may be modified as follows to implement the present invention. The above-described embodiments and the following modifications may be combined with each other. The present invention also includes configurations in which the components of the above-described embodiments and modifications are appropriately combined. Furthermore, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-described embodiments and modifications, and various modifications are possible.

[0032] In the embodiment described above, the plunger barrel 30 has the lower narrow diameter portion 34, but it may be configured not to have the lower narrow diameter portion 34. In this modified example, a portion of the plunger barrel 30 is not inserted into the main body 40. In addition, 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.

[0033] In the above-described embodiment, the outer diameter of the large diameter portion 35 is smaller than the width of the main body 40 , but the outer diameter of the large diameter portion 35 may be larger than the width of the main body 40 . [Explanation of symbols]

[0034] 1 fuel injection valve 2 fuel injection pumps 3 Accumulator control valve block 10. Discharge valve cover 20 Discharge valve seat cover 21 Discharge valve seat 30 Plunger barrel 31 Plunger hole 32 Fuel compression chamber 40 Main Unit 41 flange 42 Fuel supply path 43 Fuel discharge path 50 plunger 60 Booster cylinder 61 Booster piston 1000 fuel injector

Claims

1. a main body having a flange and a hole formed axially at the center; a plunger barrel disposed in contact with the main body and having a hole formed in the axial direction at its center; a plunger that moves along the bore of the body and the bore of the plunger barrel; a discharge valve facing the hole of the plunger barrel and facing the plunger; and a fuel compression chamber is provided in the hole of the plunger barrel between the tip of the plunger and the discharge valve; the flange has a passage through which fuel compressed in the fuel compression chamber passes; The main body is fixed to the installation location by a bolt that is passed through the flange. Fuel injection pump.

2. the flange is provided on a portion extending from a region in contact with the plunger barrel in a direction intersecting the axial direction, the passage in the flange opens to a side surface of the flange; The main body is fixed to an installation location by a bolt passed through a hole that passes through the flange in the vertical direction.

2. The fuel injection pump according to claim 1.

3. The plunger is connected to the fuel compression chamber and has a passage through which the fuel passes.

2. The fuel injection pump according to claim 1.

4. The thickness of the plunger barrel is greater than the diameter of the plunger in the radial direction of the fuel compression chamber.

2. The fuel injection pump according to claim 1.

Images