Fuel pump

Abstract

To simplify a structure, reduce machining costs, and suppress generation of fuel pressure pulsation, in a fuel pump.SOLUTION: A fuel pump comprises: a pump head; a plurality of plunger barrel units in which a plurality of plungers are movably supported and provided with a plurality of pressurization chambers for pressurizing fuel with the movement of the plungers, and which are mounted in parallel on the pump head; a plurality of discharge valve units arranged in a plurality of fuel discharge passages provided in a pump head so as to communicate with the plurality of pressurization chambers; a plurality of suction valve units that is arranged in a plurality of fuel suction passages provided in the pump head so as to communicate with the plurality of pressurization chambers; a fuel discharge side communication passage communicating with the plurality of fuel discharge passages; and a connector that can supply fuel of the fuel discharge side communication passage to the outside.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a fuel pump applied to an internal combustion engine.

Background Art

[0002] For example, a common rail type fuel injection device applied to a diesel engine includes a fuel pump, a common rail, and a fuel injection valve. The fuel pump sucks and pressurizes the fuel in the fuel tank and supplies it to the common rail as high-pressure fuel. The common rail holds the high-pressure fuel supplied from the fuel pump at a predetermined pressure. The fuel injection valve injects the high-pressure fuel in the common rail into the combustion chamber of the diesel engine by opening and closing the injection valve. The fuel pump includes a plunger barrel, a plunger, a suction valve, and a discharge valve. When the plunger moves in one direction inside the plunger barrel, the suction valve is opened to suck fuel into the pressurizing chamber. When the plunger moves in the other direction inside the plunger barrel, the fuel in the pressurizing chamber is pressurized, the discharge valve is opened, and high-pressure fuel is discharged. Examples of such a fuel pump include those described in Patent Document 1 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a fuel pump, plungers and plunger barrels are arranged to correspond to multiple cams on the camshaft. In other words, the fuel pump is constructed by arranging plunger units, each equipped with a plunger, intake valve, and discharge valve on a plunger barrel, at intervals along the axial direction of the camshaft and connecting them to one another. As a result, each plunger unit becomes large, and the plunger barrel has a complex shape, which presents challenges in manufacturing, as well as increased manufacturing costs.

[0005] Furthermore, with multiple plunger units, each fuel discharge section is connected to the common rail through its respective connecting pipe. This results in a complex connection structure between the plunger units and the common rail, and pressure pulsations occur at different timings in each connecting pipe, negatively affecting fuel discharge volume and pressure.

[0006] This disclosure aims to solve the aforementioned problems and provide a fuel pump that simplifies the structure, reduces processing costs, and suppresses the generation of fuel pressure pulsations. [Means for solving the problem]

[0007] To achieve the above objectives, the fuel pump of this disclosure comprises a pump head, a plurality of plunger barrel units mounted in parallel to the pump head, each having a plurality of pressurizing chambers that movably support a plurality of plungers and pressurize fuel by the movement of the plungers, a plurality of discharge valve units arranged in a plurality of fuel discharge passages provided in the pump head so as to communicate with each of the plurality of pressurizing chambers, a plurality of intake valve units arranged in a plurality of fuel intake passages provided in the pump head so as to communicate with each of the plurality of pressurizing chambers, a fuel discharge side communication passage connecting the plurality of fuel discharge passages, and a connector capable of supplying fuel from the fuel discharge side communication passage to the outside. [Effects of the Invention]

[0008] The fuel pump of this disclosure can simplify the structure and reduce manufacturing costs, as well as suppress the occurrence of fuel pressure pulsations. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing the fuel injection system of this embodiment. [Figure 2] Figure 2 is a longitudinal cross-sectional view showing the fuel pump of this embodiment. [Figure 3] Figure 3 is a cross-sectional view of the fuel pump taken along line III-III in Figure 2. [Figure 4] Figure 4 is a cross-sectional view showing the connection between the pump head, plunger barrel unit, suction valve unit, and discharge valve unit. [Figure 5] Figure 5 is a cross-sectional view of the VV section of Figure 4. [Figure 6] Figure 6 is a cross-sectional view taken along the line VI-VI in Figure 4. [Figure 7] Figure 7 is a cross-sectional view showing a modified fuel intake side communication passage. [Modes for carrying out the invention]

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. However, these embodiments do not limit the present disclosure, and where there are multiple embodiments, they may be combinations of these embodiments. Furthermore, the components in the embodiments include those readily conceivable by those skilled in the art, those that are substantially identical, and those that are equivalent.

[0011] <Fuel injection device> Figure 1 is a schematic diagram showing the fuel injection system of this embodiment.

[0012] As shown in Figure 1, the fuel injection system 10 is mounted on a diesel engine (internal combustion engine). The fuel injection system 10 comprises a fuel pump 11, a common rail 12, and a plurality of fuel injection valves 13.

[0013] The fuel pump 11 is connected to the fuel tank 14 via the fuel line L11. The fuel pump 11 draws fuel stored in the fuel tank 14 from the fuel line L11 and pressurizes it to produce high-pressure fuel. The fuel pump 11 is connected to the common rail 12 via the high-pressure fuel line L12. The common rail 12 adjusts the high-pressure fuel supplied from the fuel pump 11 to a predetermined pressure. The common rail 12 is connected to fuel injectors 13 via a plurality (four in this embodiment) of fuel supply lines L13. The fuel injectors 13 inject the high-pressure fuel from the common rail 12 into each cylinder (combustion chamber) of the diesel engine by opening and closing the injectors.

[0014] <Fuel pump> Figure 2 is a longitudinal cross-sectional view of the fuel pump of this embodiment, and Figure 3 is a cross-sectional view taken along line III-III in Figure 2, showing a longitudinal cross-section of the fuel pump. The fuel pump described below is of a type with three plungers, but the number of plungers is not limited to this configuration.

[0015] Figures 2 and 3 As shown, the fuel pump 11 is formed by bolting together a retainer 21, a pump case 22, and a pump head 23 to create a housing. The pump case 22 houses a camshaft 24. The camshaft 24 is rotatably supported by the retainer 21 at each axial end by bearings 25 and 26. One axial end of the camshaft 24 protrudes outside the retainer 21, and is supplied with driving force from the diesel engine. The camshaft 24 is provided with multiple (three in this embodiment) cams 27, 28, and 29 spaced apart in the axial direction. The cams 27, 28, and 29 each have different circumferential phases.

[0016] The retainer 21 is fastened to the pump case 22 by multiple bolts 30. The multiple bolts 30 pass through the retainer 21 and their ends are screwed into the pump case 22. The pump head 23 is fastened to the pump case 22 by multiple bolts 31. The multiple bolts 31 pass through the pump head 23 and are screwed into the pump case 22.

[0017] The pump case 22 and the pump head 23 have three plunger barrels 32, 33, 34 disposed therein. Each of the plunger barrels 32, 33, 34 has a similar configuration. The pump case 22 and the pump head 23 are provided with three accommodation holes 35, 36, 37 along a direction orthogonal to the axial direction of the camshaft 24. The accommodation holes 35, 36, 37 are formed across the pump case 22 and the pump head 23. Each of the plunger barrels 32, 33, 34 is disposed in each of the accommodation holes 35, 36, 37. That is, each of the plunger barrels 32, 33, 34 has a first shaft portion 32a, 33a, 34a, a second shaft portion 32b, 33b, 34b, and a third shaft portion 32c, 33c, 34c along the axial direction. The outer diameters of the plunger barrels 32, 33, 34 decrease in the order of the first shaft portion 32a, 33a, 34a, the second shaft portion 32b, 33b, 34b, and the third shaft portion 32c, 33c, 34c. The plunger barrels 32, 33, 34 are supported by the accommodation holes 35, 36, 37 with the first shaft portions 32a, 33a, 34a.

[0018] Each of the plunger barrels 32, 33, 34 has support holes 38, 39, 40 formed therein along the axial direction. The support holes 38, 39, 40 penetrate each of the plunger barrels 32, 33, 34 in the axial direction. Plungers 41, 42, 43 are disposed in each of the support holes 38, 39, 40 of the plunger barrels 32, 33, 34. Each of the plungers 41, 42, 43 is supported movably along the axial direction in the support holes 38, 39, 40 of each of the plunger barrels 32, 33, 34.

[0019] Tappets 44, 45, 46 and rollers 47, 48, 49 are respectively arranged between plungers 41, 42, 43 and cams 27, 28, 29. The rollers 47, 48, 49 are rotatably supported by the tappets 44, 45, 46 by support shafts 50, 51, 52. Spring sheets 41a, 42a, 43a are arranged at the lower end portions in the axial direction of the plungers 41, 42, 43. Compression coil springs 53, 54, 55 are arranged between plunger barrels 32, 33, 34 and spring sheets 41a, 42a, 43a. The compression coil springs 53, 54, 55 press the plungers 41, 42, 43 against the tappets 44, 45, 46 by the biasing force acting on the spring sheets 41a, 42a, 43a, and press the rollers 47, 48, 49 against the cams 27, 28, 29 through the tappets 44, 45, 46. The outer peripheral surfaces of the rollers 47, 48, 49 contact the outer peripheral surfaces of the cams 27, 28, 29.

[0020] Pressurization chambers 56, 57, 58 are formed on one end side in the axial direction in support holes 38, 39, 40 of the plunger barrels 32, 33, 34. The pressurization chambers 56, 57, 58 are partitioned by the inner peripheral surfaces of the support holes 38, 39, 40, the end surfaces on one end side in the axial direction of the plungers 41, 42, 43, and the end surfaces of discharge valves 64, 65, 66 and suction valves 61, 62, 63 described later. By moving the plungers 41, 42, 43 to one end side in the axial direction of the support holes 38, 39, 40, the fuel sucked into the pressurization chambers 56, 57, 58 can be pressurized.

[0021] The pump head 23 is equipped with suction valves 61, 62, and 63, and discharge valves 64, 65, and 66. The pump head 23 is provided with fuel passages 67, 68, and 69 that communicate with the support holes 38, 39, and 40 of the plunger barrels 32, 33, and 34, respectively. The fuel passages 67, 68, and 69 are arranged in a straight line with the support holes 38, 39, and 40. One end of each fuel passage 67, 68, and 69 communicates with the support holes 38, 39, and 40, one end of each fuel passage communicates with the suction passages (fuel suction passages) 70, 71, and 72 in the middle, and one end of each fuel passage (fuel discharge passage) 73, 74, and 75 at the other end. The suction passages 70, 71, and 72 are provided in a direction perpendicular to the fuel passages 67, 68, and 69. Furthermore, fuel passages 67, 68, and 69 are used as part of the fuel intake passage and fuel discharge passage.

[0022] Intake passages 70, 71, and 72 are equipped with intake valves 61, 62, and 63. Intake valves 61, 62, and 63 are biased by compression coil springs 76, 77, and 78 to open intake passages 70, 71, and 72, and are operated by actuators 79, 80, and 81 to close intake passages 70, 71, and 72. Discharge passages 73, 74, and 75 are equipped with discharge valves 64, 65, and 66. Discharge valves 64, 65, and 66 are biased by compression coil springs 82, 83, and 84 to close discharge passages 73, 74, and 75, and are operated by fuel pressure to open discharge passages 73, 74, and 75. In this case, pressurized chambers 56, 57, and 58 are connected to fuel passages 67, 68, and 69 and intake passages 70, 71, and 72.

[0023] The three intake passages 70, 71, and 72 are connected by a connecting passage (fuel intake side connecting passage) 85. The fuel line L11 from the fuel tank 14 (see Figure 1) is connected to the connecting passage 85. The discharge passages 73 and 75 are closed by plugs 86 and 87 at the other ends. The discharge passage 74 has a connector 88 at the other end. The three discharge passages 73, 74, and 75 are also connected by a connecting passage (fuel discharge side connecting passage) 89. The common rail 12 (see Figure 1) is connected to the connector 88 via the high-pressure fuel line L12. The connecting passage 89 connects the discharge passages 73, 74, and 75, but it may be arranged in a straight line intersecting the discharge passages 73, 74, and 75 and providing direct communication, or it may be arranged offset from the discharge passages 73, 74, and 75 in the direction perpendicular to the plane of the paper in Figure 2 and providing indirect communication.

[0024] Therefore, when the camshaft 24 rotates, the rotational force is converted into reciprocating force by the cams 27, 28, and 29 and transmitted to the rollers 47, 48, 49 and tappets 44, 45, and 46. The movement of the rollers 47, 48, 49 and tappets 44, 45, and 46 causes the plungers 41, 42, and 43 to reciprocate along the axial direction in the support holes 38, 39, and 40 of the plunger barrels 32, 33, and 34. The intake valves 61, 62, and 63 open the intake passages 70, 71, and 72, and when the plungers 41, 42, and 43 move to the other side in the axial direction (downward in Figures 2 and 3), the low-pressure fuel in the communication passage 85 is drawn into the pressurized chambers 56, 57, and 58 via the intake passages 70, 71, and 72 and the fuel passages 67, 68, and 69. After the plungers 41, 42, and 43 reach bottom dead center, when the actuators 79, 80, and 81 are activated in the process of moving towards top dead center, the intake valves 61, 62, and 63 move over the biasing force of the compression coil springs 76, 77, and 78, closing the intake passages 70, 71, and 72.

[0025] With low-pressure fuel drawn into the pressurizing chambers 56, 57, and 58, when plungers 41, 42, and 43 move to one side in the axial direction (upward in Figures 2 and 3), before actuators 79, 80, and 81 are activated, the low-pressure fuel is returned from the intake passages 70, 71, and 72 through the intake valves 61, 62, and 63 to the connecting passage 85. After actuators 79, 80, and 81 are activated, the low-pressure fuel is closed by the intake valves 61, 62, and 63, and the volume of the pressurizing chambers 56, 57, and 58 is reduced, pressurizing the low-pressure fuel in the pressurizing chambers 56, 57, and 58. When the low-pressure fuel in the pressurizing chambers 56, 57, and 58 is pressurized to a predetermined pressure, the discharge valves 64, 65, and 66 move against the biasing force of the compression coil springs 82, 83, and 84 and the pressure received from the common rail 12, opening the discharge passages 73, 74, and 75. Then, the high-pressure fuel in the pressurizing chambers 56, 57, and 58 is discharged from the fuel passages 67, 68, and 69 into the discharge passages 73, 74, and 75. The high-pressure fuel in the discharge passages 73, 74, and 75 then merges in the connecting passage 89 and is discharged from the connector 88 into the high-pressure fuel line L12 (see Figure 1). Subsequently, when the plungers 41, 42, and 43 reach top dead center, the discharge of high-pressure fuel ends, and as the plungers 41, 42, and 43 begin to move to the other side in the axial direction, the volume of the pressurizing chambers 56, 57, and 58 expands, causing the pressure in the pressurizing chambers 56, 57, and 58 to decrease. The discharge valves 64, 65, and 66 move due to the biasing force of the compression coil springs 82, 83, and 84 and the pressure received from the common rail 12, closing the discharge passages 73, 74, and 75.

[0026] <Unitization of fuel pumps> Figure 4 is a cross-sectional view showing the connection between the pump head, plunger barrel unit, suction valve unit, and discharge valve unit; Figure 5 is a cross-sectional view of section VV in Figure 4; and Figure 6 is a cross-sectional view of section VI-VI in Figure 4.

[0027] As shown in Figures 4 to 6, the pump head 23 is fastened to the pump case 22 by bolts 31. The pump case 22 and the pump head 23 are provided with housing holes 35, 36, and 37 inside, and the plunger barrels 32, 33, and 34 are supported in the housing holes 35, 36, and 37. That is, the first shaft portions (protrusions) 32a, 33a, and 34a of the plunger barrels 32, 33, and 34 are housed in the housing holes 35, 36, and 37. The axial ends of the plunger barrels 32, 33, and 34 are fastened to the pump head 23. Multiple bolts 91 pass through the pump head 23, and their tips are screwed into the first shaft portions 32a, 33a, and 34a of the plunger barrels 32, 33, and 34.

[0028] The plunger barrels 32, 33, and 34 have support holes 38, 39, and 40 formed therein, and the plungers 41, 42, and 43 are movably supported in the support holes 38, 39, and 40. The pump head 23 is provided with fuel passages 67, 68, and 69, which are in a straight line with the support holes 38, 39, and 40. The fuel passages 67, 68, and 69 are in a straight line with the intake passages 70, 71, and 72, and the discharge passages 73, 74, and 75 are in a straight line with them. Intake valves 61, 62, and 63 are arranged in the intake passages 70, 71, and 72, and discharge valves 64, 65, and 66 are arranged in the fuel passages 67, 68, and 69 and the discharge passages 73, 74, and 75.

[0029] In this embodiment, the plunger barrels 32, 33, and 34, the suction valves 61, 62, and 63, and the discharge valves 64, 65, and 66 are each unitized and mounted on the pump head 23. The plunger barrel units 32A, 33A, and 34A are mounted in parallel on the pump head 23. The suction valve units 61A, 62A, and 63A are arranged in the respective suction passages 70, 71, and 72. The discharge valve units 64A, 65A, and 66A are arranged in the respective fuel passages 67, 68, and 69 and the respective discharge passages 73, 74, and 75.

[0030] As shown in Figure 4, the plunger barrel units 32A, 33A, and 34A are composed of plunger barrels 32, 33, and 34, and plungers 41, 42, and 43. However, the plunger barrel units 32A, 33A, and 34A are not limited to this configuration and may include, for example, tappets 44, 45, and 46, rollers 47, 48, and 49, support shafts 50, 51, and 52, and compression coil springs 53, 54, and 55.

[0031] Next, we will describe the intake valve units 61A, 62A, and 63A. However, since the intake valve units 61A, 62A, and 63A have similar configurations, we will only describe the intake valve unit 62A.

[0032] As shown in Figure 4, the pump head 23 is provided with a fuel passage 68, an intake passage 71, and a discharge passage 74. The support hole 39, the fuel passage 68, and the discharge passage 74 are arranged in a straight line and communicate with each other. The intake passage 71 is arranged perpendicular to the fuel passage 68, and one end communicates with the fuel passage 68. The pump head 23 has a housing recess 101 formed in communication with the other end of the intake passage 71. The housing recess 101 contains an intake valve case 102 and a fixing member 103. The intake valve case 102 supports an intake valve 62 so as to be movable in the axial direction and is located on the intake passage 71 side of the housing recess 101. The fixing member 103 is located on the opening side of the housing recess 101 in contact with the intake valve case 102 and is fixed to the pump head 23, thereby positioning and fixing the intake valve case 102 to the pump head 23.

[0033] A compression coil spring 77 is positioned between the intake valve 62 and the intake valve case 102. The intake valve 62 is Biasing force of compression coil spring 77The intake valve 62 is supported in a direction that opens the intake passage 71. The intake valve 62 is movable by the actuator 80 to close the intake passage 71. The pump head 23 has connecting passages 104 and 105 formed on both radial sides of the intake valve 62, along a direction intersecting the intake passage 71. The connecting passages 104 and 105 communicate with the intake passage 71 through openings 106 and 107 formed in the intake valve case 102. The two connecting passages 85 consist of connecting passages 104 and 105 and openings 106 and 107. The two connecting passages 85 are positioned radially offset to one side and the other side with respect to the center position of the intake passages 70, 71, and 72 (intake valves 61, 62, and 63), and can connect each of the intake passages 70, 71, and 72.

[0034] The intake valve units 61A, 62A, and 63A consist of intake valves 61, 62, and 63, compression coil springs 76, 77, and 78, and actuators 79, 80, and 81, in addition to an intake valve case 102 and a fixing member 103. However, the intake valve units 61A, 62A, and 63A are not limited to this configuration; for example, the actuators 79, 80, and 81 may be separate units.

[0035] As shown in Figure 5, fuel passages 67, 68, and 69 are connected to discharge passages 73, 74, and 75, and discharge valves 64, 65, and 66 are positioned across the fuel passages 67, 68, and 69 and the discharge passages 73, 74, and 75. Compression coil springs 82 and 84 are positioned between the discharge valves 64 and 66 and the plugs 86 and 87, and a compression coil spring 83 is positioned between the discharge valve 65 and the connector 88. The discharge valves 64, 65, and 66 are biased and supported by the compression coil springs 82, 83, and 84 in the direction of closing the discharge passages 73, 74, and 75, and when the fuel pressure in the pressurizing chambers 56, 57, and 58 exceeds the discharge pressure, they open the discharge passages 73, 74, and 75.

[0036] The three discharge passages 73, 74, and 75 are connected by a connecting passage 89. In this case, the connecting passage 89 is in a straight line along a direction perpendicular to the fuel passages 67, 68, 69 and the discharge passages 73, 74, and 75. The connecting passage 89 connects discharge passages 73, 74, and 75. A connector 88 is provided at the end of discharge passage 74. Note that the connector 88 may be provided in discharge passage 73 or 75 instead of discharge passage 74, or it may be provided to connect to the connecting passage 89.

[0037] Discharge valve units 64A, 65A, and 66A consist of discharge valves 64, 65, and 66 and compression coil springs 82, 83, and 84. However, the discharge valve units 64A, 65A, and 66A are not limited to this configuration.

[0038] The fuel pump 11 has multiple plunger barrel units 32A, 33A, 34A, multiple suction valve units 61A, 62A, 63A, and multiple discharge valve units 64A, 65A, 66A independently mounted on the pump head 23. This simplifies the structure of the pump head 23, plunger barrel units 32A, 33A, 34A, suction valve units 61A, 62A, 63A, and discharge valve units 64A, 65A, 66A. Furthermore, since the discharge passages 73, 74, 75 are connected by a connecting passage 85 of the pump head 23, the pressure pulsation of the high-pressure fuel discharged from the discharge passages 73, 74, 75 to the connecting passage 85 is mitigated in the connecting passage 85, and the pressure pulsation of the fuel discharged from the connector 88 to the high-pressure fuel line L12 is suppressed.

[0039] <Variations of pump heads> Figure 7 is a cross-sectional view showing a modified fuel intake side communication passage.

[0040] In a modified version of this embodiment, as shown in Figure 7, intake passages 70, 71, and 72 are arranged with intake valves 61, 62, and 63. The intake valves 61, 62, and 63 are biased by compression coil springs 76, 77, and 78 (see Figure 4) in a direction that closes the intake passages 70, 71, and 72. The three intake passages 70, 71, and 72 are connected by a connecting passage (fuel intake side connecting passage) 111. The connecting passage 111 is located at the center of the intake passages 70, 71, and 72 (intake valves 61, 62, and 63) and can connect each intake passage 70, 71, and 72.

[0041] [Effects of this embodiment] The fuel pump according to the first embodiment includes a pump head 23 and a plurality of plunger barrel units 32A, 33A, 34A mounted in parallel to the pump head 23, each of which is provided with a plurality of pressurizing chambers 56, 57, 58 that movably support a plurality of plungers 41, 42, 43 and pressurize the fuel by the movement of the plungers 41, 42, 43. multiple The system includes multiple discharge valve units 64A, 65A, and 66A arranged in multiple discharge passages 73, 74, and 75 provided in the pump head 23 so as to communicate with pressurized chambers 56, 57, and 58 respectively; multiple suction valve units 61A, 62A, and 63A arranged in multiple suction passages 70, 71, and 72 provided in the pump head 23 so as to communicate with multiple pressurized chambers 56, 57, and 58 respectively; a connecting passage (fuel discharge side connecting passage) 89 connecting the multiple discharge passages 73, 74, and 75; and a connector 88 capable of supplying fuel from the connecting passage 89 to the outside.

[0042] According to the first embodiment of the fuel pump, by independently mounting the plunger barrel units 32A, 33A, 34A, the suction valve units 61A, 62A, 63A, and the discharge valve units 64A, 65A, 66A to the pump head 23, the structure of the pump head 23, the plunger barrel units 32A, 33A, 34A, the suction valve units 61A, 62A, 63A, and the discharge valve units 64A, 65A, 66A can be simplified, and processing costs can be reduced. Furthermore, by arranging multiple plunger barrel units 32A, 33A, 34A in parallel with the pump head 23, the design can be easily modified according to the number of plunger barrel units 32A, 33A, 34A. Furthermore, since the discharge passages 73, 74, and 75 are connected by the connecting passage 85 of the pump head 23, the pressure pulsation of the high-pressure fuel discharged from the discharge passages 73, 74, and 75 into the connecting passage 85 is mitigated in the connecting passage 85, thereby suppressing the pressure pulsation of the fuel discharged from the connector 88 to the high-pressure fuel line L12.

[0043] In the fuel pump according to the second embodiment, the multiple discharge passages 73, 74, 75 are arranged in a straight line with respect to the multiple support holes 38, 39, 40, each of which supports a multiple plunger 41, 42, 43 so as to be movable. Communication path 89 The multiple discharge passages 73, 74, and 75 are connected in a manner that intersects with each other, while the multiple intake passages 70, 71, and 72 are connected to the multiple discharge passages 73, 74, and 75 between the multiple pressurizing chambers 56, 57, and 58 and the connecting passage 89, respectively, in a manner that intersects with each other. As a result, the pressurizing chambers 56, 57, and 58 are connected only to the fuel passages 67, 68, and 69, and the inner diameter of the support holes 38, 39, and 40 that constitute the pressurizing chambers 56, 57, and 58 can be reduced.

[0044] In the third embodiment of the fuel pump, the connector 88 is provided in one of the multiple discharge passages 73, 74, and 75. This allows the connector 88 to serve as the plug for both the discharge passages 73, 74, and 75, thereby simplifying the structure.

[0045] In the fourth embodiment of the fuel pump, the plunger barrel units 32A, 33A, and 34A are provided with first shaft portions (protrusions) 32a, 33a, and 34a on one end side in the axial direction, and the pump head 23 is provided with housing holes (recesses) 35, 36, and 37, and the first shaft portions 32a, 33a, and 34a are positioned by fitting into the housing holes 35, 36, and 37. This allows the plunger barrel units 32A, 33A, and 34A to be mounted on the pump head 23 with high precision.

[0046] In the fifth embodiment of the fuel pump, a pair of connecting passages (fuel intake side connecting passages) 85 that connect a plurality of intake passages 70, 71, and 72 are provided on both radial sides of the intake passages 70, 71, and 72. As a result, fuel is supplied from the pair of connecting passages 85 to the intake passages 70, 71, and 72, and even if air is mixed with the fuel, the mixed air is quickly discharged into the pressurizing chambers 56, 57, and 58, thereby suppressing fluctuations in the fuel discharge amount.

[0047] In the embodiment described above, the support holes 38, 39, and 40 were made of the same diameter in the axial direction, and one end was connected to the fuel passages 67, 68, and 69. Limited This is not the case. For example, the support holes may be composed of a main body hole having the same diameter as the support holes 38, 39, and 40, and a smaller diameter portion having a smaller diameter than the support holes 38, 39, and 40, with the smaller diameter portion communicating with the fuel passages 67, 68, and 69. In this case, the plungers 41, 42, and 43 are supported so as to be movable only by the main body holes.

[0048] Furthermore, the configuration of the fuel injection system 10 and the fuel pump 11 are not limited to the embodiments described above. For example, the number of common rails 12 and fuel injectors 13, the connection positions of the fuel pump 11, and the number of plungers 41, 42, 43 and plunger barrels 32, 33, 34 can be set as appropriate. [Explanation of Symbols]

[0049] 10 Fuel injection device 11 Fuel pump 12 Common Rail 13 Fuel Injector 14 Fuel tank 21 Retainer 22 Pump Case 23 Pump Head 24 Camshaft 25,26 Bearings 27, 28, 29 Cam 30,31 volts 32, 33, 34 Plunger barrel 35, 36, 37 Receiving holes (recesses) 38,39,40 Support hole 41, 42, 43 Plungers 44, 45, 46 tappets 47, 48, 49 Laura 50,51,52 Support shaft 53, 54, 55 Compression coil springs 61, 62, 63 Inhalation valve 64, 65, 66 Discharge valves 67,68,69 Fuel passage 70,71,72 Suction passage 73,74,75 Discharge passage 76, 77, 78 Compression coil springs 79, 80, 81 Actuators 82, 83, 84 Compression coil springs 85 Communication passage (fuel intake side communication passage) 86,87 plug 88 connectors 89 Communication path (fuel discharge side communication path) 91 volts 101 Recessed housing 102 Inhalation valve case 103 Fixing member 104,105 Communication path 106,107 Openings L11 Fuel Line L12 Fuel High-Pressure Line L13 Fuel supply line

Claims

1. Pump head and Multiple plunger barrel units are mounted in parallel to the pump head, each having multiple plungers that are movably supported and multiple pressurizing chambers that pressurize the fuel by the movement of the plungers, A plurality of discharge valve units are arranged in a plurality of fuel discharge passages provided in the pump head so as to communicate with each of the plurality of pressurizing chambers, A plurality of intake valve units are arranged in a plurality of fuel intake passages provided in the pump head so as to communicate with each of the plurality of pressurized chambers, and are operated by actuators, A fuel discharge side communication passage that connects the aforementioned multiple fuel discharge passages, A connector capable of supplying fuel to the outside from the fuel discharge side communication passage, Equipped with, The pump head has a receiving recess that communicates with one end of the fuel intake passage. The aforementioned intake valve unit includes an intake valve, an intake valve case that movably supports the intake valve inside, and a fixing member. The intake valve case is positioned on the fuel intake passage side of the housing recess, The fixing member is positioned on the opening side of the housing recess while in contact with the intake valve case. The suction valve case is then positioned and fixed to the pump head. The discharge valve unit includes a discharge valve directly positioned in the fuel discharge passage and a compression coil spring provided in the fuel discharge passage on the side of the discharge valve opposite to the pressurizing chamber, which biases the discharge valve in a direction that closes the discharge passage. The fuel discharge side communication passage communicates with the space in the fuel discharge passage where the compression coil spring is located. Fuel pump.

2. The plurality of fuel intake passages communicate with the plurality of fuel discharge passages between the plurality of pressurizing chambers and the fuel discharge side communication passage, respectively, The fuel pump according to claim 1.

3. The pump head is provided with a recess, the plunger barrel unit includes a plunger barrel, and the plunger barrel is provided with a protrusion on one end in the axial direction that has the largest outer diameter when viewed from the axial direction. The plunger barrel unit is positioned by the convex portion fitting into the concave portion. A fuel pump according to claim 1 or claim 2.

4. Fuel intake side connecting passages that connect the plurality of fuel intake passages are provided on both radial sides of the fuel intake passage. A fuel pump according to any one of claims 1 to 3.

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