Pressurizing assembly for high-pressure pump, plunger sleeve for pressurizing assembly, and high-pressure pump

Abstract

The utility model relates to a pressurizing assembly for a high-pressure pump, a plunger sleeve for the pressurizing assembly and the high-pressure pump. The pressurizing assembly is used for increasing the pressure of fuel supplied to the high-pressure pump and comprises a plunger sleeve and a plunger capable of reciprocating in a plunger hole of the plunger sleeve. The plunger sleeve is of a split type structure. Therefore, different parts of the plunger sleeve can be manufactured by using different materials, so that the cost of the pressurizing assembly is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-pressure pumps, and in particular to a plunger assembly for a high-pressure pump and a plunger sleeve for the plunger assembly. BACKGROUND

[0002] In an engine system, fuel is supplied to an engine by a fuel supply system. In order to supply fuel to the engine, the fuel supply system draws fuel from a fuel tank by a delivery pump (also known as a low-pressure pump or a pre-delivery pump) and delivers it to a high-pressure pump, in which the fuel is pressurized to reach a sufficient injection pressure, thereby ensuring that the fuel can be efficiently injected into the cylinder of the engine.

[0003] As a core component of a high-pressure pump, the plunger assembly needs to be made of a material that has high fatigue resistance (high tensile strength with a certain toughness) to withstand alternating pressure, high hardness to reduce wear, and high purity to avoid early fatigue failure. On a diesel high-pressure pump, the commonly used material for the high-pressure assembly is high-carbon alloy steel with appropriate heat treatment or low-carbon alloy steel with carbonitriding.

[0004] With the growth of the global economy and the increasing population, energy demand continues to rise. The supply of traditional petroleum fuels is gradually tightening, and the price fluctuates greatly, which prompts people to start looking for alternative energy sources. As clean and efficient energy, such as methanol, is gradually becoming an important choice to replace petroleum fuels. However, ordinary methanol is corrosive to ordinary carbon steel or alloy steel used in existing high-pressure pumps. Although pure methanol, i.e., high-concentration methanol, theoretically has no effect on ordinary steel within 100°C, it is difficult to avoid absorbing water or mixing with other impurities over a long period of use due to its strong water absorption, thereby causing corrosion. Therefore, as a mass-produced, long-term used methanol high-pressure pump, the steel material in contact with methanol should have corrosion resistance.

[0005] However, there are very few stainless steels that meet all the above requirements at home and abroad. At the same time, the cost of stainless steel materials that meet the above requirements is very expensive. According to the existing design, the cost of the methanol high-pressure pump will increase significantly only in the use of materials. It is difficult to meet the project development requirements to develop new materials and supporting heat treatment schemes, which requires a lot of time and cost. INVENTION CONTENTS

[0006] The purpose of the present application is to solve or at least alleviate at least some of the problems existing in the prior art.

[0007] A first aspect of the present application is to provide a plunger assembly for a high-pressure pump, the plunger assembly being configured to increase the pressure of fuel supplied to the high-pressure pump, the plunger assembly comprising a plunger sleeve and a plunger reciprocable in a plunger bore of the plunger sleeve. Here, the plunger sleeve is configured in a split type.

[0008] In the prior art, the plunger sleeve as the core component of the booster assembly is of an integrated construction. Thus, the same material must be used to manufacture the plunger sleeve. In order to meet the requirements of fatigue strength, hardness, purity and corrosion resistance, the entire plunger sleeve must be made of expensive materials, thereby resulting in a very high cost of the booster assembly and the high-pressure pump. By constructing the plunger sleeve in a split manner, different materials can be used to manufacture different parts of the plunger sleeve, thereby reducing the cost of the plunger sleeve and the booster assembly. Here, for example, only the part of the plunger sleeve that is in direct contact with high-pressure fuel can be made of a material with high fatigue strength, high hardness, high purity and / or high corrosion resistance, such as special stainless steel, while the remaining part that is not in direct contact with high-pressure fuel can be made of ordinary stainless steel. In terms of the plunger sleeve itself, the use of special stainless steel can reduce by more than 85%.

[0009] Optionally, the plunger sleeve comprises a plunger sleeve shell and a plunger sleeve core accommodated in the plunger sleeve shell, and the plunger hole is formed in the plunger sleeve core. Here, the plunger sleeve core is the part of the plunger sleeve that is in direct contact with high-pressure fuel, while the plunger sleeve shell is used to accommodate the plunger sleeve core and is generally not in direct contact with high-pressure fuel, and thus the plunger sleeve shell can be made of ordinary stainless steel, while only the plunger sleeve core is made of a material with high fatigue strength, high hardness, high purity and / or high corrosion resistance, such as special stainless steel.

[0010] Optionally, the plunger sleeve shell has first and second end faces opposite to each other along the axial direction and sequentially forms a valve assembly accommodating cavity, a plunger sleeve core accommodating cavity and a seal accommodating cavity from the first end face to the second end face, wherein the plunger sleeve core is accommodated in the plunger sleeve core accommodating cavity.

[0011] Optionally, the plunger sleeve core has an annular groove on the outer surface and a backflow hole extending from the plunger hole to the annular groove along the radial direction, and the plunger sleeve shell has a drain passage extending from the outside of the plunger sleeve shell to the annular groove.

[0012] In the case of an integrated construction of the plunger sleeve, the drain passage directly opens into the plunger hole of the plunger sleeve obliquely, thereby the drain passage has a large intersection width with the plunger hole, thereby excessively occupying the high-pressure sealing length between the plunger and the plunger sleeve. By constructing the plunger sleeve in a split manner, a backflow hole extending along the radial direction can be machined in the plunger sleeve core, thereby the backflow hole substantially perpendicularly intersects with the inner wall of the plunger sleeve core and can achieve a small intersection width, thereby saving the high-pressure sealing length between the plunger and the plunger sleeve core.

[0013] Optionally, the backflow hole is located closer to the second end face of the plunger sleeve shell along the axial direction than the position where the elongated line of the leakage passage intersects with the inner wall of the plunger sleeve core.

[0014] In the case of the plunger sleeve of the integrated structure, due to the limitation of the machining condition, the position where the leakage passage intersects with the inner wall of the plunger sleeve is usually also far away from the second end face of the plunger sleeve (corresponding to the second end face of the plunger sleeve shell), thereby failing to fully utilize the high-pressure sealing length between the plunger and the plunger sleeve. Although the high-pressure sealing length can be more fully utilized by increasing the inclination of the leakage passage, the increase of the inclination is limited due to the shape limitation of the plunger sleeve, otherwise there is a risk that the leakage passage penetrates the plunger sleeve. Moreover, as the inclination increases, the intersection width of the leakage passage and the plunger hole further increases, thereby the contribution to the high-pressure sealing length is limited. The increase of the inclination also increases the length of the leakage passage, thereby increasing the difficulty of machining. By the split structure of the plunger sleeve, the backflow hole can be arranged at a position closer to the second end face of the plunger sleeve shell, thereby the high-pressure sealing length between the plunger and the plunger sleeve core can be more fully utilized. Thus, the high-pressure sealing length can be increased by about 15% while keeping the size of the plunger sleeve unchanged.

[0015] Optionally, the plunger sleeve core has a first section facing the second end face of the plunger sleeve shell and a second section facing away from the second end face of the plunger sleeve shell, the first section has a first outer diameter and the second section has a second outer diameter, the first outer diameter is smaller than the second outer diameter, thereby forming an axial shoulder between the first section and the second section, the axial shoulder is supported on a corresponding shoulder formed in the plunger sleeve core receiving cavity along the axial direction, wherein the annular groove and the backflow hole are arranged in the first section.

[0016] Optionally, the plunger sleeve shell has an axial stop between the plunger sleeve core receiving cavity and the seal receiving cavity, for the seal of the plunger to be assembled into the seal receiving cavity from the second end face of the plunger sleeve shell and supported on the axial stop along the axial direction, and for the plunger sleeve core to be assembled into the plunger sleeve core receiving cavity from the first end face of the plunger sleeve shell and supported on the axial stop along the axial direction. Optionally, the seal comprises a bush sealed relative to the plunger sleeve shell and a sealing body fixedly received in the bush and sealed relative to the plunger.

[0017] Alternatively, the plunger sleeve has an axial stop at the second end face for the sealing element of the plunger to be mounted into the sealing element receiving cavity from the first end face of the plunger sleeve and to be supported on the axial stop in axial direction, and the plunger sleeve core is likewise mounted into the plunger sleeve core receiving cavity from the first end face of the plunger sleeve and supported on the sealing element in axial direction. Optionally, the sealing element is constituted only by a sealing body sealed against the plunger. Thereby, on the one hand, the costs for the sealing element itself can be reduced, since an additional bushing is omitted. Furthermore, the machining requirements for the sealing element receiving cavity of the plunger sleeve can be reduced, and thus the machining costs, since the sealing body is directly in contact with the plunger sleeve here, so that there is no need to increase the machining requirements for the plunger sleeve in order to ensure the sealing between the plunger sleeve and the bushing of the sealing element, but the sealing element receiving cavity can be machined directly by a shaping tool.

[0018] When the axial stop is located between the plunger sleeve core receiving cavity and the sealing element receiving cavity, the plunger sleeve core receiving cavity and the sealing element receiving cavity have to be machined from the first end face and the second end face of the plunger sleeve in two opposite directions, respectively, for which the coaxiality of the plunger sleeve core receiving cavity and the sealing element receiving cavity has to be ensured for the sealing, so that complex tooling fixtures or more advanced machine tools are required. By arranging the axial stop at the second end face of the plunger sleeve, the machining difficulty and costs of the plunger sleeve can be reduced, since the plunger sleeve core receiving cavity and the sealing element receiving cavity can be machined from the first end face of the plunger sleeve in the same direction at once. Furthermore, by arranging the axial stop at the second end face of the plunger sleeve, space is provided for further increasing the high-pressure sealing length between the plunger and the plunger sleeve core. Without changing the size of the plunger sleeve, the high-pressure sealing length can be increased by up to about 23%.

[0019] Optionally, an inlet valve assembly is mounted into the valve assembly receiving cavity from the first end face of the plunger sleeve and pressed against the plunger sleeve core in axial direction, and an outlet valve assembly is mounted into the valve assembly receiving cavity from the first end face of the plunger sleeve and presses the inlet valve assembly and the plunger sleeve core against the corresponding shoulder in the plunger sleeve core receiving cavity of the plunger sleeve in axial direction.

[0020] Optionally, the plunger sleeve is made of a first material and the plunger sleeve core is made of a second material, wherein the second material has a higher fatigue strength and / or hardness and / or purity and / or corrosion resistance than the first material.

[0021] A second aspect of the present application is to provide a plunger sleeve for the supercharging assembly.

[0022] A third aspect of the present application is to provide a high-pressure pump having at least one of the booster assemblies. BRIEF DESCRIPTION OF DRAWINGS

[0023] Embodiments of the present application will be described in further detail below with reference to the accompanying drawings, but those skilled in the art will appreciate that the drawings are for illustrative purposes only and should not be construed as limiting the scope of the present application. Herein, the drawings show:

[0024] Figure 1 is a cross-sectional view of a booster assembly according to a first embodiment of the present application;

[0025] Figure 2 is a cross-sectional view of a booster assembly according to a second embodiment of the present application;

[0026] Figure 3 is a cross-sectional view of a booster assembly according to a third embodiment of the present application;

[0027] Figure 4 is a cross-sectional view of a plunger sleeve according to an embodiment of the present application;

[0028] Figure 5 is an enlarged view of a booster assembly according to a second embodiment of the present application;

[0029] Figure 6 is an enlarged view of a booster assembly according to a third embodiment of the present application. DETAILED DESCRIPTION

[0030] Figure 1 A booster assembly 10 according to a first embodiment of the present application is shown in cross-sectional view. The booster assembly 10 is used in a high-pressure pump for increasing the pressure of fuel supplied to the high-pressure pump to a sufficient injection pressure, thereby ensuring that the fuel can be efficiently injected into a cylinder of an engine. Herein, the high-pressure pump can be, for example, a diesel high-pressure pump, a gasoline high-pressure pump, or a methanol high-pressure pump. However, with the advent of dual-fuel engines, the high-pressure pump can also be a dual-fuel high-pressure pump, such as a methanol-diesel dual-fuel high-pressure pump.

[0031] The booster assembly 10 includes a plunger sleeve 11. In Figure 1In the first embodiment shown, the plunger sleeve 11 is of one-piece construction. A plunger bore is provided in the plunger sleeve 11, and a plunger 12 is supported in the plunger bore of the plunger sleeve 11 so as to be able to perform a reciprocating motion. Here, the plunger 12 is able to be driven by a not-shown drive assembly of the high-pressure pump to perform the reciprocating motion. Along the axial direction, on both sides of the plunger bore, the plunger sleeve 11 also has a valve assembly accommodating cavity (located above the plunger bore) in which an inlet valve assembly 15 and an outlet valve assembly 14 are installed, and a seal accommodating cavity (located below the plunger bore) in which a seal 13 is installed. In order to supply fuel to the intensifier assembly 10, the plunger sleeve 11 also has an inflow passage 16 that extends from the outside of the plunger sleeve 11 into the valve assembly accommodating cavity and is in fluid connection with the inlet valve assembly 15. At the same time, in order to lead a leakage flow of high-pressure fuel away from the intensifier assembly 10, the plunger sleeve 11 also has a leakage flow passage 17 that extends from the plunger bore to the outside of the plunger sleeve 11.

[0032] Figure 2 An intensifier assembly 10 according to a second embodiment of the present application is shown in a sectional view. Like the intensifier assembly 10 according to the first embodiment of the present application shown in Figure 1 The intensifier assembly 10 according to the second embodiment of the present application shown comprises a plunger sleeve 11 in which a plunger bore 28 (see Fig. 2) is provided, and a plunger 12 is able to perform a reciprocating motion in the plunger bore 28 of the plunger sleeve 11. Figure 4

[0033] However, unlike the intensifier assembly 10 according to the first embodiment of the present application shown, Figure 1 Figure 2 The plunger sleeve 11 of the intensifier assembly 10 according to the second embodiment of the present application shown is of split construction. Specifically, the plunger sleeve 11 comprises a plunger sleeve shell 18 and a plunger sleeve core 19 accommodated in the plunger sleeve shell 18, and the plunger bore 28 is formed in the plunger sleeve core 19. The plunger sleeve shell 18 has a first end face (an upper end face in Fig. 2) and a second end face (a lower end face in Fig. 2) opposite to each other along the axial direction. Figure 2 Figure 2 ​​​and the second end surface, an inlet valve assembly 15 and an outlet valve assembly 14 are accommodated in the valve assembly accommodating cavity, a plunger sleeve 19 is accommodated in the plunger sleeve accommodating cavity, and a seal 13 is accommodated in the seal accommodating cavity. In order to supply fuel to the intensifier assembly 10, the plunger sleeve shell 18 has an inflow passage 16 extending from the outside of the plunger sleeve shell 18 into the valve assembly accommodating cavity and fluidly connected to the inlet valve assembly 15. Meanwhile, in order to lead a leakage flow of high-pressure fuel out of the intensifier assembly 10, the plunger sleeve 19 has an annular groove 26 on the outer surface and a backflow hole 27 extending from the plunger hole 28 into the annular groove 26 in the radial direction (see Figure 4 ), and the plunger sleeve shell 18 has a leakage passage 17 extending from the outside of the plunger sleeve shell 18 into the annular groove 26.

[0034] In Figure 1 the case of the plunger sleeve 11 of the integrated construction according to the first embodiment of the present application shown in FIG. 1, due to the limitation of the machining condition, the leakage passage 17 directly opens into the plunger hole 28 of the plunger sleeve 11 obliquely, whereby the leakage passage 17 has a large intersection width with the plunger hole 28, thus excessively occupying the high-pressure seal length between the plunger 12 and the plunger sleeve 11. By separating the plunger sleeve 11, the backflow hole 27 extending in the radial direction can be machined in the plunger sleeve 19, whereby the backflow hole 27 substantially perpendicularly intersects the inner wall of the plunger sleeve 19 and can achieve a small intersection width with the plunger hole 28, thus saving the high-pressure seal length between the plunger 12 and the plunger sleeve 19.

[0035] Further, the backflow hole 27 can intersect the inner wall of the plunger sleeve 19 closer to the second end surface of the plunger sleeve shell 18 than the position at which the extension line of the leakage passage 17 intersects the inner wall of the plunger sleeve 19 in the axial direction, thus being able to further intensify the high-pressure seal length between the plunger 12 and the plunger sleeve 19.

[0036] In the case of the one-piece construction of the plunger sleeve 11, due to the limitation of the machining condition, the position where the leakage passage 17 intersects with the inner wall of the plunger sleeve 11 is usually also far away from the second end surface of the plunger sleeve 11 (corresponding to the second end surface of the plunger sleeve shell 18), whereby the high-pressure sealing length between the plunger 12 and the plunger sleeve 11 cannot be fully utilized. Although the high-pressure sealing length can be more fully utilized by increasing the inclination of the leakage passage 17, due to the shape limitation of the plunger sleeve 11, the increase of the inclination is limited, otherwise there is a risk that the leakage passage 17 penetrates the plunger sleeve 11. Moreover, with the increase of the inclination, the intersection width of the leakage passage 17 and the plunger hole 28 is further increased, whereby the contribution to the high-pressure sealing length is limited. The increase of the inclination also increases the length of the leakage passage 17, thereby increasing the difficulty of machining. Through the split construction of the plunger sleeve 11, the return flow hole 27 can be arranged at a position closer to the second end surface of the plunger sleeve shell 18, whereby the high-pressure sealing length between the plunger 12 and the plunger sleeve core 19 can be more fully utilized. Thereby, the high-pressure sealing length can be increased by about 15% while keeping the size of the plunger sleeve 11 unchanged.

[0037] In Figure 2 the second embodiment shown, the plunger sleeve shell 18 has an axial stop 20 between the plunger sleeve core accommodating cavity and the seal accommodating cavity, for the seal 13 of the plunger 12 to be fitted into the seal accommodating cavity from the second end surface of the plunger sleeve shell 18 and supported on the axial stop 20 in the axial direction, while the plunger sleeve core 19 is fitted into the plunger sleeve core accommodating cavity from the first end surface of the plunger sleeve shell 18 and supported on the axial stop 20 in the axial direction. Here, the axial stop 20 can be formed by a diameter reduction of the inner wall of the plunger sleeve shell 18, for example.

[0038] Figure 3 A cross-sectional view shows a supercharging assembly 10 according to a third embodiment of the application. Like the supercharging assembly 10 according to the second embodiment of the application shown in Figure 2 the supercharging assembly 10 according to the third embodiment of the application shown in Figure 3 the plunger sleeve 11 of the supercharging assembly 10 according to the third embodiment of the application shown in is also constructed in a split manner. Specifically, the plunger sleeve 11 comprises a plunger sleeve shell 18 and a plunger sleeve core 19 accommodated in the plunger sleeve shell 18, and the plunger hole 28 is formed in the plunger sleeve core 19. The plunger sleeve shell 18 has a first end surface (upper end surface in Figure 3 ) and a second end surface (lower end surface in Figure 3and the second end face, an inlet valve assembly 15 and an outlet valve assembly 14 are accommodated in the valve assembly accommodating cavity, a plunger sleeve 19 is accommodated in the plunger sleeve accommodating cavity, and a seal 13 is accommodated in the seal accommodating cavity. In order to supply fuel to the intensifier assembly 10, the plunger sleeve 18 has an inflow passage 16 which extends from the outside of the plunger sleeve 18 into the valve assembly accommodating cavity and is fluidly connected to the inlet valve assembly 15. At the same time, in order to lead a leakage flow of high-pressure fuel away from the intensifier assembly 10, the plunger sleeve 19 has an annular groove 26 on the outer surface and a return flow hole 27 which extends from the plunger bore 28 into the annular groove 26 in the radial direction, and the plunger sleeve 18 has a leakage flow passage 17 which extends from the outside of the plunger sleeve 18 into the annular groove 26.

[0039] However, unlike the intensifier assembly 10 according to the second embodiment of the application shown in Figure 2 In the third embodiment shown in Figure 3 In the third embodiment shown in

[0040] By arranging the axial stop 20 at the second end face of the plunger sleeve 18, the machining difficulty and cost of the plunger sleeve 18 can be reduced, because the plunger sleeve accommodating cavity and the seal accommodating cavity can be machined from the first end face of the plunger sleeve 18 in the same direction at once. Furthermore, by arranging the axial stop 20 at the second end face of the plunger sleeve 18, there is room for further increasing the high-pressure sealing length between the plunger 12 and the plunger sleeve 19. In comparison with the first embodiment shown in Figure 1 In comparison with the first embodiment shown in

[0041] In the third embodiment shown in Figure 2 and Figure 3In the shown embodiment, after the plunger sleeve core 19 has been mounted into the plunger sleeve core receiving cavity of the plunger sleeve housing 18, the inlet valve assembly 15 can be assembled into the valve assembly receiving cavity from the first end face of the plunger sleeve housing 18 and pressed in axial direction against the plunger sleeve core 19, and then the outlet valve assembly 14 can be assembled into the valve assembly receiving cavity from the first end face of the plunger sleeve housing 18 and pressed in axial direction against the inlet valve assembly 15 and the plunger sleeve core 19 on the corresponding shoulder in the plunger sleeve core receiving cavity of the plunger sleeve housing 18.

[0042] Figure 4 A plunger sleeve core 19 according to an embodiment of the present application is shown in a sectional view. In the shown embodiment, the plunger sleeve core 19 has a first section 21 facing the second end face of the plunger sleeve housing 18 and a second section 22 facing away from the second end face of the plunger sleeve housing 18, the first section 21 having a first outer diameter and the second section 22 having a second outer diameter, the first outer diameter being smaller than the second outer diameter, whereby a shoulder 23 is formed between the first section 21 and the second section 22, the shoulder 23 being supported in axial direction on a corresponding shoulder formed in the plunger sleeve core receiving cavity, wherein the annular groove 26 and the return flow opening 27 are arranged in the first section 21. Figure 2 and Figure 3 As can be seen more clearly, the plunger sleeve core 19 has a first section 21 facing the second end face of the plunger sleeve housing 18 and a second section 22 facing away from the second end face of the plunger sleeve housing 18, the first section 21 having a first outer diameter and the second section 22 having a second outer diameter, the first outer diameter being smaller than the second outer diameter, whereby a shoulder 23 is formed between the first section 21 and the second section 22, the shoulder 23 being supported in axial direction on a corresponding shoulder formed in the plunger sleeve core receiving cavity, wherein the annular groove 26 and the return flow opening 27 are arranged in the first section 21. By forming a shoulder 23 between the first section 21 and the second section 22, the plunger sleeve core 19 can be more stably supported in the plunger sleeve housing 18. However, this is not necessary, in an embodiment not shown, the plunger sleeve core 19 can also have a uniform outer diameter, whereby the plunger sleeve core 19 is only supported on the axial stop 20 (shown in Figure 2 embodiment) or only on the seal 13 (shown in Figure 3 embodiment).

[0043] Figure 5 A partial enlarged view of a booster assembly 10 according to a second embodiment of the present application in the region of the seal 13 is shown. Figure 2 As can be seen more clearly from Figure 5 the seal 13 comprises a bushing 25 which is sealed with respect to the plunger sleeve housing 18 and a sealing body 24 which is fixedly received in the bushing 25 and which is sealed with respect to the plunger 12. Here, the seal 13 is fixedly mounted in the seal receiving cavity of the plunger sleeve housing 18 by means of the bushing 25.

[0044] Figure 6 A partial enlarged view of a booster assembly 10 according to a third embodiment of the present application in the region of the seal 13 is shown. Figure 3 As can be seen more clearly fromFigure 6 As can be seen more clearly, the seal 13 consists only of a sealing body 24 that seals relative to the plunger 12. That is, the seal 13 here does not... Figure 2 and Figure 5 The bushing 25 is shown in the diagram. This reduces the cost of the seal itself by eliminating the need for an additional bushing 25. Furthermore, it reduces the machining requirements for the seal cavity of the plunger housing 18, thereby lowering machining costs. This is because the seal body 24 directly contacts the plunger housing 18, eliminating the need to increase the machining requirements of the plunger housing 18 to ensure a seal between the plunger housing 18 and the bushing 25 of the seal 13; the seal cavity can be directly machined using a forming tool.

[0045] exist Figures 2 to 6 In the illustrated embodiment, when the plunger sleeve 11 is composed of a separate plunger sleeve housing 18 and a plunger sleeve core 19, the plunger sleeve housing 18 and the plunger sleeve core 19 can be made of different materials. For example, the plunger sleeve housing 18 can be made of a first material and the plunger sleeve core 19 can be made of a second material. Since the plunger sleeve core 19 is in direct contact with high-pressure fuel, the second material has higher fatigue strength and / or hardness and / or purity and / or corrosion resistance than the first material. In particular, to meet the requirements of methanol fuel, the second material can be selected from special stainless steels. Suitable stainless steel materials for the plunger sleeve core 19 can be, for example, 9Cr18MoV stainless steel, X30 stainless steel, M390 stainless steel, etc. For the plunger sleeve housing 18, ordinary stainless steel can be selected. Suitable stainless steel materials for the plunger sleeve housing 18 can be, for example, 304 stainless steel, 316 stainless steel, 17-4PH stainless steel, etc. Of course, the materials used for the plunger housing 18 and the plunger core 19 described above are merely exemplary, and this application is not limited to the materials exemplified above.

[0046] The above descriptions are merely exemplary embodiments of this application. The scope of protection of this application is not limited to the above embodiments, and all technical solutions falling within the concept of this application are within the scope of protection of this application. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of this application should also be considered within the scope of protection of this application.

Claims

1. A booster assembly (10) for a high-pressure pump for increasing the pressure of fuel supplied to the high-pressure pump, the booster assembly (10) comprising a plunger sleeve (11) and a plunger (12) reciprocable in a plunger bore (28) of the plunger sleeve (11), characterized in that the plunger sleeve (11) is configured in a split manner.

2. The booster assembly (10) according to claim 1, characterized in that the plunger sleeve (11) comprises a plunger sleeve shell (18) and a plunger sleeve core (19) accommodated in the plunger sleeve shell (18), the plunger bore (28) being formed in the plunger sleeve core (19).

3. The booster assembly (10) according to claim 2, characterized in that the plunger sleeve shell (18) has a first end face and a second end face opposite to each other along an axial direction and sequentially forms, from the first end face to the second end face, a valve assembly accommodating cavity, a plunger sleeve core accommodating cavity and a seal accommodating cavity, wherein the plunger sleeve core (19) is accommodated in the plunger sleeve core accommodating cavity.

4. The booster assembly (10) according to claim 3, characterized in that the plunger sleeve core (19) has an annular groove (26) on an outer surface and a backflow hole (27) extending from the plunger bore (28) into the annular groove (26) along a radial direction, and the plunger sleeve shell (18) has a drain passage (17) extending from an outer side of the plunger sleeve shell (18) into the annular groove (26).

5. The booster assembly (10) according to claim 4, characterized in that the backflow hole (27) is closer to the second end face of the plunger sleeve shell (18) than a position where an extension line of the drain passage (17) intersects with an inner wall of the plunger sleeve core (19) along the axial direction.

6. The booster assembly (10) according to claim 4, characterized in that the plunger sleeve core (19) has a first section (21) facing the second end face of the plunger sleeve shell (18) and a second section (22) facing away from the second end face of the plunger sleeve shell (18), the first section (21) has a first outer diameter and the second section (22) has a second outer diameter, the first outer diameter is smaller than the second outer diameter, thereby forming a shoulder (23) between the first section (21) and the second section (22), the shoulder (23) is supported on a corresponding shoulder formed in the plunger sleeve core accommodating cavity along the axial direction, wherein the annular groove (26) and the backflow hole (27) are arranged in the first section (21).

7. The booster assembly (10) according to claim 3, characterized in that The plunger sleeve housing (18) has an axial stop (20) between the plunger sleeve core accommodation cavity and the seal accommodation cavity for the seal (13) of the plunger (12) to be fitted into the seal accommodation cavity from the second end face of the plunger sleeve housing (18) and to be supported in the axial direction on the axial stop (20), while the plunger sleeve core (19) is fitted into the plunger sleeve core accommodation cavity from the first end face of the plunger sleeve housing (18) and is supported in the axial direction on the axial stop (20).

8. The intensifier assembly (10) according to claim 3, characterized in that The plunger sleeve housing (18) has an axial stop (20) at the second end face for the seal (13) of the plunger (12) to be fitted into the seal accommodation cavity from the first end face of the plunger sleeve housing (18) and to be supported in the axial direction on the axial stop (20), and the plunger sleeve core (19) is likewise fitted into the plunger sleeve core accommodation cavity from the first end face of the plunger sleeve housing (18) and is supported in the axial direction on the seal (13).

9. The intensifier assembly (10) according to claim 6, characterized in that The inlet valve assembly (15) is fitted into the valve assembly accommodation cavity from the first end face of the plunger sleeve housing (18) and is pressed in the axial direction against the plunger sleeve core (19), and the outlet valve assembly (14) is fitted into the valve assembly accommodation cavity from the first end face of the plunger sleeve housing (18) and presses the inlet valve assembly (15) and the plunger sleeve core (19) in the axial direction against the corresponding shoulder in the plunger sleeve core accommodation cavity of the plunger sleeve housing (18).

10. The intensifier assembly (10) according to claim 7, characterized in that The seal (13) comprises a bushing (25) which is sealed with respect to the plunger sleeve housing (18) and a seal body (24) which is fixedly accommodated in the bushing (25) and is sealed with respect to the plunger (12).

11. The intensifier assembly (10) according to claim 8, characterized in that The seal (13) consists only of a seal body (24) which is sealed with respect to the plunger (12).

12. The intensifier assembly (10) according to claim 2, characterized in that The plunger sleeve housing (18) is made of a first material and the plunger sleeve core (19) is made of a second material, wherein the second material has a higher fatigue strength and / or hardness and / or purity and / or corrosion resistance than the first material.

13. A plunger sleeve (11) characterized in that The plunger sleeve (11) is a plunger sleeve (11) of an intensifier assembly (10) according to any one of claims 1 to 12.

14. A high pressure pump characterized by, The high-pressure pump has at least one intensifier assembly (10) according to any one of claims 1 to 12.

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