CN115030846A

CN115030846A - High pressure fuel pump

Info

Publication number: CN115030846A
Application number: CN202210792244.2A
Authority: CN
Inventors: 李振强; 吴永煌; 王佳新; 顾浩
Original assignee: FAW Jiefang Automotive Co Ltd
Current assignee: FAW Jiefang Automotive Co Ltd
Priority date: 2022-07-07
Filing date: 2022-07-07
Publication date: 2022-09-09
Anticipated expiration: 2042-07-07
Also published as: CN115030846B

Abstract

The utility model relates to a high pressure fuel pump, which comprises a pump body, plunger and sealing member, be equipped with the pump sending room in the pump body and with the passageway of pump sending room intercommunication, pump body surface is equipped with the opening with the passageway intercommunication, inwards cave in on the inner wall of passageway and be formed with the spacing groove, the opening part is equipped with the guide way with the spacing groove intercommunication, the plunger activity is worn to locate in the passageway, the sealing member is located between the plunger and the pump body sealedly, the protruding stopper that is equipped with in periphery of sealing member, the stopper is constructed to get into the spacing groove via the guide way, in order to carry on spacingly to the sealing member. Above-mentioned high pressure fuel pump through setting up the sealing member, prevents that the fuel in the pumping chamber from revealing. Through setting up the stopper on the sealing member to set up spacing groove and guide way, make when the sealing member is installed into the passageway from the opening part of the pump body in, the stopper can get into the spacing inslot through the guide way, thereby spacing to the sealing member, consequently when the relative pump body motion of plunger, make the sealing member be difficult for droing from the plunger, avoid sealing member sealing failure.

Description

High pressure fuel pump

Technical Field

The application relates to the technical field of vehicle fuel injection systems, in particular to a high-pressure fuel pump.

Background

High pressure fuel pumps are used as components of vehicle fuel injection systems and function to draw fuel from a fuel chamber and deliver it under pressure to a fuel supply line. Specifically, a movable plunger is arranged in the high-pressure fuel pump, and fuel easily leaks into a lubricating oil cavity through a gap outside the plunger in the plunger oil pressing process. To this end, the related art provides a high pressure fuel pump that isolates fuel from lubricant by providing a seal on the plunger.

However, since the seal ring moves together with the plunger, the high-pressure fuel pump in the related art has a problem of seal failure caused by easy falling of the seal member.

Disclosure of Invention

Therefore, the high-pressure fuel pump which is not easy to lose the sealing performance needs to be provided aiming at the problem that the sealing performance is lost due to the fact that the sealing piece is easy to fall off in the high-pressure fuel pump in the related technology.

According to an aspect of the present application, there is provided a high pressure fuel pump comprising:

the pump comprises a pump body, a pump chamber and a channel communicated with the pump chamber are arranged in the pump body, an opening communicated with the channel is formed in the surface of the pump body, a limiting groove is formed in the inner wall of the channel in an inwards recessed mode, and a guide groove communicated with the limiting groove is formed in the opening;

the plunger is movably arranged in the channel in a penetrating way; and

the sealing element is arranged between the plunger and the pump body in a sealing mode, a limiting block is arranged on the periphery of the sealing element in a protruding mode, and the limiting block is constructed to enter the limiting groove through the guide groove so as to limit the sealing element.

According to the high-pressure fuel pump, the pump body is provided with the pumping chamber and the channel communicated with the pumping chamber, and the plunger movably arranged in the channel in a penetrating mode is arranged, so that the plunger can extend into the pumping chamber, the volume of the pumping chamber is changed, the pressure of fuel is changed, and oil absorption or oil pressing is achieved. By providing a seal to seal between the plunger and the side wall of the passage, leakage of fuel from within the pumping chamber is prevented. Through setting up the stopper on the sealing member to inwards cave in and form the spacing groove on setting up the inner wall of passageway, set up the guide way with the spacing groove intercommunication at the opening part, make when the sealing member is installed into the passageway from the opening part of the pump body in, the stopper can get into the spacing inslot through the guide way, thereby spacing to the sealing member, consequently when the relative pump body motion of plunger, make the sealing member be difficult for droing from the plunger, avoid the sealing member to become invalid.

In one embodiment, the limiting groove has a first end communicated with the guide groove and a second end opposite to the first end;

still inwards cave in on the inner wall of passageway and be formed with and be used for holding the spacing chamber of stopper, spacing chamber with the second end intercommunication.

In one embodiment, the cross-sectional dimension of the limiting groove perpendicular to the direction from the first end to the second end gradually decreases from the first end to the second end.

In one embodiment, the guide groove is arranged along the longitudinal extension direction of the channel;

the limiting groove is arranged around the axis of the channel.

In one embodiment, the channels include a first channel and a second channel, which are sequentially arranged along the longitudinal extension direction of the channels, wherein the first channel is communicated with the opening, and the second channel is communicated with the pumping chamber;

the cross-sectional dimension of the second channel perpendicular to the longitudinal extension direction of the channel is smaller than the cross-sectional dimension of the first channel perpendicular to the longitudinal extension direction of the channel;

the inner wall of the first channel is inwards sunken to form the limiting groove and the guide groove, and the sealing element is arranged in the first channel.

In one embodiment, the inner wall of the second channel is inwards sunken to form an oil drainage groove surrounding the second channel;

and an oil drainage channel communicated with the oil drainage groove is arranged in the pump body.

In one embodiment, an oil inlet communicated with the pumping chamber is formed in the pump body, and the oil drainage channel is communicated with the oil inlet.

In one embodiment, the sealing element is recessed inwardly along the channel between the ends in the longitudinal direction of extension to form a groove.

In one embodiment, from one end to the other end of the groove in the longitudinal extension direction of the channel, the cross-sectional dimension of the groove perpendicular to the longitudinal extension direction of the channel gradually increases and then gradually decreases.

In one embodiment, the high pressure fuel pump further comprises a first support assembly and a second support assembly, the first support assembly and the second support assembly being disposed within the seal member at a distance from each other along a lengthwise extension of the passage;

the first support component comprises a plurality of first support members which are arranged around the axis of the channel at intervals, and the cross section of each first support member perpendicular to the longitudinal extension direction of the channel is gradually increased from one end of each first support member close to the second support component along the longitudinal extension direction of the channel to the other end of each first support member;

the second support component comprises a plurality of second support members which are arranged around the axis of the channel at intervals, and the cross section size of the second support members perpendicular to the longitudinal extension direction of the channel is gradually increased from one end of the second support members close to the first support component to the other end along the longitudinal extension direction of the channel.

Drawings

FIG. 1 is a cross-sectional view of a pump body according to an embodiment of the present application;

FIG. 2 is a schematic view of the assembly of the pump body, plunger and seal of the embodiment of FIG. 1;

FIG. 3 is a cross-sectional view of the seal of the embodiment of FIG. 1;

FIG. 4 is a schematic structural view of a limiting groove and a guide groove in the embodiment shown in FIG. 1;

FIG. 5 is a cross-sectional view in another direction of the pump body in the embodiment of FIG. 1;

FIG. 6 is a cross-sectional view of a pump body according to another embodiment of the present application.

Description of reference numerals:

10. a pump body; 12. a pumping chamber; 13. a channel; 131. a first channel; 132. a second channel; 14. an opening; 15. an oil drainage channel; 16. an oil path; 17. an oil inlet; 18. an oil outlet; 20. a plunger; 30. a seal member; 40. a limiting groove; 41. a first end; 42. a second end; 50. a guide groove; 60. a limiting block; 70. a limiting cavity; 80. a groove; 90. a first support assembly; 91. a first support; 100. a second support assembly; 101. a second support member; 110. an oil drainage groove; A. the longitudinal extension of the channel.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiment in many different forms than those described herein and those skilled in the art will be able to make similar modifications without departing from the spirit of the application and therefore the application is not limited to the specific embodiments disclosed below.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as the case may be.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

FIG. 1 is a cross-sectional view of a pump body according to an embodiment of the present application; FIG. 2 is a schematic view of the assembly of the pump body, plunger and seal of the embodiment of FIG. 1; fig. 3 is a cross-sectional view of the seal in the embodiment of fig. 1.

Referring to fig. 1 to 3, a high pressure fuel pump according to an embodiment of the present application includes a pump body 10, a plunger 20, and a seal 30.

The pump body 10 is internally provided with a pumping chamber 12 and a channel 13 communicated with the pumping chamber 12, the surface of the pump body 10 is provided with an opening 14 communicated with the channel 13, the inner wall of the channel 13 is inwards sunken to form a limiting groove 40, and the opening 14 is provided with a guide groove 50 communicated with the limiting groove 40. The plunger 20 is movably disposed through the channel 13. The sealing member 30 is sealingly provided between the plunger 20 and the pump body 10, and a stopper 60 is protruded on an outer circumference of the sealing member 30, and the stopper 60 is configured to be able to enter the stopper groove 40 via the guide groove 50 to stop the sealing member 30.

According to the high-pressure fuel pump, the pumping chamber 12 and the channel 13 communicated with the pumping chamber 12 are arranged in the pump body 10, and the plunger 20 is movably arranged in the channel 13 in a penetrating manner, so that the plunger 20 can extend into the pumping chamber 12, the volume of the pumping chamber 12 is changed, the pressure applied to fuel is changed, and oil absorption or oil pressing is realized. By providing the seal 30 between the plunger 20 and the pump body 10, fuel in the pumping chamber 12 is prevented from leaking through a gap between the plunger 20 and the pump body 10. By arranging the limiting block 60 on the sealing element 30, forming the limiting groove 40 on the inner wall of the channel 13 in an inward concave manner, and arranging the guide groove 50 communicated with the limiting groove 40 at the opening 14, when the sealing element 30 is installed into the channel 13 from the opening 14 of the pump body 10, the limiting block 60 can enter the limiting groove 40 through the guide groove 50, so that the sealing element 30 is limited, and therefore when the plunger 20 moves relative to the pump body 10, the sealing element 30 is not easy to fall off from the plunger 20, and sealing failure of the sealing element 30 is avoided. In addition, since the high pressure fuel pump described above enables the seal member 30 to be fixed between the plunger 20 and the passage 13 without providing an additional component, the seal member 30 is easy to assemble, and the structure of the high pressure fuel pump is simple.

Alternatively, as shown in connection with fig. 1-3, the guide groove 50 is disposed along the lengthwise extension of the channel 13, and the retaining groove 40 is disposed around the axis of the channel 13. In this manner, by arranging the guide groove 50 along the lengthwise extending direction (i.e., the direction a in fig. 1) of the channel 13, it is convenient to move the stopper 60 from the end of the guide groove 50 at the opening 14 to the end of the guide groove 50 communicating with the stopper groove 40, and thus, it is convenient to assemble the sealing member 30 connected with the stopper 60 to the pump body 10. By arranging the limiting groove 40 around the axis of the channel 13, the limiting block 60 can be installed at one end of the limiting groove 40 far away from the guide groove 50, so that the limiting block 60 is far away from the guide groove 50. In addition, because the plunger 20 moves relative to the pump body 10 along the longitudinal extending direction of the channel 13 during the operation of the plunger 20, the plunger 20 is not easy to drive the sealing member 30 to rotate relative to the pump body 10 around the axis of the channel 13, and the stopper 60 is not easy to move into the guide groove 50 along the stopper groove 40, so that the stopper 60 is further prevented from being separated from the guide groove 50, that is, the sealing member 30 is further prevented from being separated from the plunger 20.

Fig. 4 is a schematic structural view of a limiting groove and a guide groove in the embodiment shown in fig. 1.

In some embodiments, as shown in fig. 4, the limiting groove 40 has a first end 41 communicating with the guide groove 50 and a second end 42 opposite to the first end 41, and a limiting cavity 70 for accommodating the limiting block 60 is formed on the inner wall of the channel 13 and is recessed inwards, and the limiting cavity 70 is communicated with the second end 42. So, through the spacing chamber 70 that sets up the second end 42 intercommunication with spacing groove 40, make stopper 60 get into spacing groove 40 back through guide way 50, can get into spacing chamber 70 through spacing groove 40 again to it is spacing by spacing chamber 70, further prevent that stopper 60 from droing from guide way 50 after through spacing groove 40, prevent that the sealing member 30 who is connected with stopper 60 from droing from plunger 20, thereby make sealing member 30's sealed more reliable.

Specifically, as shown in fig. 4, the spacing cavity 70 has a first side communicating with the spacing groove 40 and a second side opposite to the first side, and the cross-sectional dimension of the spacing cavity 70 perpendicular to the direction from the second side to the first side is larger than the cross-sectional dimension of the spacing groove 40 perpendicular to the direction from the first end 41 to the second end 42. Thus, the stopper 60 located in the stopper cavity 70 is not easily inserted into the stopper groove 40 through the first side of the stopper cavity 70.

In one embodiment, the stopper 60 is configured to have an interference fit with the stopper groove 40 and is configured to have a clearance fit with the stopper cavity 70. Thus, even if the plunger 20 rotates relative to the pump body 10 around the axis of the channel 13, the stopper 60 is not easy to enter the stopper groove 40 from the stopper cavity 70, so that the plunger 20 is not easy to drive the sealing element 30 and the stopper 60 to rotate relative to the pump body 10, and the sealing element 30 falls off from the plunger 20.

In some embodiments, the cross-sectional dimension of the retaining groove 40 perpendicular to the direction from the first end 41 to the second end 42 decreases gradually from the first end 41 to the second end 42, so that the pressing force applied to the retaining block 60 increases gradually during the process of passing the retaining block 60 through the retaining groove 40, thereby facilitating the installation of the retaining block 60 into the retaining cavity 70.

Therefore, during the actual assembly process, the sealing element 30 is placed into the channel 13 through the opening 14 of the pump body 10, and the stopper 60 is aligned with the guide groove 50, so that the stopper 60 and the sealing element 30 move together relative to the pump body 10 along the longitudinal extension direction of the channel 13, and the stopper 60 is located at one end of the guide groove 50 communicating with the stopper groove 40. Then, the sealing element 30 is rotated around the axis of the channel 13 relative to the pump body 10 to drive the stopper 60 to move from the first end 41 to the second end 42 of the stopper groove 40, and then the stopper 60 is pressed into the stopper cavity 70, thereby completing the assembly of the sealing element 30 and the pump body 10. The plunger 20 is then inserted through the seal 30 to assemble the plunger 20 with the pump body 10.

In order to avoid the sealing element 30 obstructing the movement of the plunger 20 relative to the sealing element 30, the material of the sealing element 30 may be a low friction material with sealing property, such as teflon.

Alternatively, the sealing member 30 and the stopper 60 may be integrally formed by injection molding, so that the sealing member 30 and the stopper 60 are reliably connected.

In some embodiments, as shown in connection with fig. 1-3, the sealing member 30 is recessed inwardly between the ends of the channel 13 in the direction of longitudinal extension to form a groove 80. It should be noted that both ends of the passage 13 are used to communicate with the fuel chamber and the lubricating oil chamber, respectively. Therefore, by providing the seal member 30 recessed inwardly between both ends in the longitudinal extending direction of the passage 13 to form the groove 80, both ends of the seal member 30 can be pressed between the plunger 20 and the pump body 10. The end of the sealing member 30 close to the pumping chamber 12 prevents the fuel in the fuel chamber from entering the lubricating oil chamber through the space between the plunger 20 and the pump body 10, thereby preventing the fuel from diluting the lubricating oil and causing abrasion of parts such as the cam roller and the like. The end of the seal 30 remote from the pumping chamber 12 prevents oil in the oil cavity from entering the fuel cavity, thereby preventing oil from entering the fuel cavity and causing deterioration of engine emissions and affecting engine performance.

Alternatively, from one end to the other end of the groove 80 in the longitudinal extension direction of the channel 13, the cross-sectional dimension of the groove 80 perpendicular to the longitudinal extension direction of the channel 13 gradually increases and then gradually decreases. In this manner, the seal 30 is easily installed in the pump body 10, and the plunger 20 is easily movably inserted into the seal 30. Further, by providing the groove 80 with a gradually increasing cross-sectional size and then gradually decreasing, the volume of the seal 30 that is tightly compressed between the plunger 20 and the pump body 10 is increased.

In some embodiments, as shown in connection with fig. 1-3, the high pressure fuel pump further includes a first support assembly 90 and a second support assembly 100, the first and

second support assemblies

90, 100 being disposed within the seal 30 spaced from one another along the lengthwise extension of the passage 13. The first support member 90 includes a plurality of first support members 91 disposed around the axis of the channel 13 at intervals from one end of the first support member 91 near the second support member 100 in the lengthwise extension direction of the channel 13 to the other end, and the first support member 91 has a cross-sectional dimension that gradually increases perpendicular to the lengthwise extension direction of the channel 13. The second support member 100 includes a plurality of second support members 101 disposed around the axis of the passage 13 at intervals from one end of the second support member 101 near the first support member 90 in the longitudinal extension direction of the passage 13 to the other end, and the second support member 101 has a cross-sectional dimension perpendicular to the longitudinal extension direction of the passage 13 that gradually increases. In this way, by providing the plurality of first supporting members 91 and the plurality of second supporting members 101, the inner wall and the outer wall of the sealing member 30 are brought into close contact with the plunger 20 and the pump body 10, respectively, thereby ensuring that the sealing member 30 is effectively sealed between the plunger 20 and the pump body 10, preventing the fuel oil from leaking to the lubricating oil chamber, and preventing the lubricating oil from entering the fuel oil chamber.

Alternatively, the first support 91 and the second support 101 may be made of metal.

In some embodiments, as shown in connection with fig. 1-2, the channel 13 comprises a first channel 131 and a second channel 132, which are arranged in sequence along the longitudinal extension of the channel, the first channel 131 being in communication with the opening 14, the second channel 132 being in communication with the pumping chamber 12. The second channel 132 has a cross-sectional dimension perpendicular to the longitudinal extension of the channel 13 that is smaller than the cross-sectional dimension of the first channel 131 perpendicular to the longitudinal extension of the channel 13. The inner wall of the first passage 131 is formed with a stopper groove 40 and a guide groove 50 depressed inward, and the sealing member 30 is disposed in the first passage 131. In this way, by providing the channel 13 including the first channel 131 and the second channel 132 and being perpendicular to the longitudinal extension direction of the channel 13, the cross-sectional dimension of the first channel 131 is larger than the cross-sectional dimension of the second channel 132, so that the first channel 131 has a space therein capable of accommodating the sealing member 30.

Figure 5 is a cross-sectional view in another direction of the pump body in the embodiment of figure 1.

In some embodiments, as shown in fig. 5, the inner wall of the second passage 132 is recessed inward to form an oil drainage groove 110 surrounding the second passage 132, and an oil drainage passage 15 communicating with the oil drainage groove 110 is provided in the pump body 10. In this way, by providing the drain groove 110, most of the fuel leaked from the pumping chamber 12 into the passage 13 can enter the drain groove 110 and then flow into the drain passage 15 communicating with the drain groove 110, thereby reducing the amount of fuel in the second passage 132, and therefore reducing the amount of fuel flowing from the second passage 132 into the first passage 131. The small portion of the fuel flowing into the first passage 131 is blocked by the sealing member 30.

It can be understood that one end of the oil drainage channel 15 is communicated with the oil drainage groove 110, and the other end of the oil drainage channel 15 can be communicated with other structures according to use requirements, so that fuel leaked into the oil drainage channel 15 can be recycled. In addition, the included angle between the extending direction of the oil drainage channel 15 and the extending direction of the channel 13 can also be set to different angles according to the use requirement.

In some embodiments, as shown in fig. 5, the drain passage 15 is adapted to communicate with the fuel tank to allow fuel in the drain passage 15 to flow to the fuel tank. Specifically, an oil passage 16 having one end communicating with the oil drain passage 15 is provided in the pump body 10, and the other end of the oil passage 16 penetrates the pump body 10 to communicate with the oil tank.

In other embodiments, as shown in fig. 6, an oil inlet 17 is provided in the pump body 10 and is communicated with the pumping chamber 12, and the oil drainage channel 15 is communicated with the oil inlet 17. It should be noted that the oil inlet 17 is used to convey fuel into the pumping chamber 12. Therefore, by communicating the oil drainage channel 15 with the oil inlet 17, the fuel oil in the oil drainage channel 15 enters the oil inlet 17 and then enters the pumping chamber 12, so that the fuel oil is effectively utilized.

In some embodiments, one side of the pumping chamber 12 communicates with the channel 13, and the pump body 10 is provided with an oil outlet 18 communicating with the other side of the pumping chamber 12, the oil outlet 18 penetrating the pump body 10. It should be noted that the oil outlet 18 is used for communicating with the fuel injector, and an oil outlet valve is arranged between the oil outlet 18 and the fuel injector. Therefore, in the actual working process, the fuel oil is driven by the pump to enter the pumping chamber 12 through the oil inlet 17, and the plunger 20 moves in the channel 13 in a reciprocating manner, so that the volume of the pumping chamber 12 is changed periodically, and the oil suction and pressure oil stroke of the high-pressure fuel pump is completed.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A high pressure fuel pump, comprising:

the plunger is movably arranged in the channel in a penetrating way; and

2. The high pressure fuel pump of claim 1, wherein the retainer groove has a first end in communication with the guide groove and a second end opposite the first end;

still inwards cave in and be formed with on the inner wall of passageway and be used for holding the spacing chamber of stopper, spacing chamber with the second end intercommunication.

3. The high pressure fuel pump of claim 2, wherein said retainer groove tapers in cross-sectional dimension perpendicular to a direction from said first end toward said second end from said first end to said second end.

4. A high pressure fuel pump according to claim 1, wherein the guide slot is disposed along a lengthwise extension of the channel;

the limiting groove is arranged around the axis of the channel.

5. A high pressure fuel pump as set forth in claim 1, wherein said passages include a first passage and a second passage in communication with said first passage disposed in series along the lengthwise extension thereof, said first passage communicating with said opening and said second passage communicating with said pumping chamber;

6. The high pressure fuel pump of claim 5, wherein the inner wall of the second passage is recessed inwardly to form a drainage groove around the second passage;

7. The high pressure fuel pump of claim 6, wherein an oil inlet is provided in the pump body in communication with the pumping chamber, the oil drainage passage being in communication with the oil inlet.

8. A high pressure fuel pump as set forth in claim 1, wherein said seal is recessed inwardly to form a groove between ends of said channel in the direction of longitudinal extension.

9. A high pressure fuel pump according to claim 8, wherein a cross-sectional dimension of the groove perpendicular to the longitudinal extension of the passage increases and decreases from one end of the groove to the other in the longitudinal extension of the passage.

10. The high pressure fuel pump of claim 9, further comprising a first support assembly and a second support assembly, the first and second support assemblies being disposed within the seal in spaced relation to one another along a lengthwise extension of the passage;