Fuel pump apparatus, system and method

Abstract

Disclosed herein are devices, systems, and methods related to high pressure fuel pump design and features. A high pressure fuel pump assembly includes a body, a cam shaft, and a boss. The body has a front end and a rear end opposite the front end and configured to be coupled to a low pressure fuel pump. The cam shaft is received and fixed within a central bore of the body so as to be rotatably movable within the central bore. A coupler end of the cam shaft is configured to be coupled to a drive shaft of the low pressure fuel pump. The boss includes at least one fastener boss configured to receive a fastener to couple the low pressure fuel pump to the high pressure fuel pump assembly. The boss can be formed at the rear end of the body such that thermal stresses that induce geometric distortion at the boss are reduced over a range of engine temperature operating conditions.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 076,753, filed on September 10, 2020, entitled “Fuel Pump Apparatus, System, and Method,” the full disclosure of which is expressly incorporated herein by reference. Technical Field

[0003] This disclosure relates generally to fuel pumps, and more particularly to fuel pumps used in conjunction with internal combustion engines. Background Technology

[0004] Internal combustion engines with common rail fuel delivery systems use high-pressure fuel pumps to ensure sufficient fuel pressure within the rail at low engine speeds and to provide a good air-fuel mixture at high engine speeds. To meter and pressurize the fuel, the high-pressure fuel pump typically has a single-piece pumping plunger that reciprocates within an orifice of a cylinder inside the pump body. The high-pressure fuel pump typically receives fuel from a low-pressure fuel pump, which draws fuel from a fuel reservoir, such as a fuel tank. Summary of the Invention

[0005] This disclosure generally relates to apparatus, systems, and methods, specifically to improved high-pressure fuel pumping devices for internal combustion engines, which exhibit enhanced reliability over the engine's operating temperature range. Based on the principles of this disclosure, designs and features for high-pressure fuel pump housings are disclosed. Such designs and features can improve the robustness of the high-pressure fuel pump in response to thermal effects by having a protrusion above the pressure zone of the high-pressure fuel pump (e.g., a zone with increased load-bearing capacity and thermal stress).

[0006] The principles of this disclosure are advantageous, especially when used in conjunction with an internal combustion engine. The advantage of this disclosure is that, within the engine's operating temperature range, the design of the high-pressure fuel pump can mitigate thermal stresses that cause geometric deformation. Other advantages include reduced torsion due to thermal effects, increased elastic drag, and the ability to accommodate large circumferential stresses. Similarly, the reduced geometric deformation provided by this disclosure results in increased structural margins for press-fit components (such as those including camshafts press-fitted into the body of the high-pressure fuel pump via bushings) and makes it possible to maintain desired clearances (e.g., between the camshaft and the bushing). Other advantages not discussed in detail herein will be apparent to those skilled in the art.

[0007] According to embodiments of this disclosure, a high-pressure fuel pump can be configured to be coupled to a low-pressure fuel pump. The high-pressure fuel pump may include a body and a protrusion. The body may have a front end and a rear end opposite the front end. The rear end may be configured to be coupled to the low-pressure fuel pump. The protrusion may include at least one fastener boss configured to receive a fastener to coupled the low-pressure fuel pump to the high-pressure fuel pump. The protrusion may be formed at the rear end of the body to reduce thermal stress that causes geometric deformation at the protrusion within the engine temperature operating conditions.

[0008] In some such examples, a protrusion may be formed above a pressure zone of the body, at which a press-fit assembly presses against the inner surface of the protrusion. In one example, the diameter of the protrusion is four times its length. In another example, the protrusion may have a generally annular shape. In yet another example, the outer circumferential wall of the protrusion may transition into a generally flat portion at the upper part of the protrusion. In a further example, the protrusion may include at least one cutout forming part of at least one fastener boss. In yet another example, the at least one cutout may extend from the outer circumferential wall of the protrusion to a sidewall of the protrusion.

[0009] In some such examples, at least one outer surface portion of the fastener boss may generally follow the contour of the outer circumferential wall of the protrusion. In examples, at least one fastener boss may be positioned at the lower portion of the protrusion to avoid a connector positioned at the lower portion of the protrusion. In some such examples, the connector includes a connector portion configured to attach a bracket to the protrusion.

[0010] Examples of this disclosure include a high-pressure fuel pump assembly that may include a body, a camshaft, and a protrusion. The body may have a front end and a rear end opposite the front end. The rear end may be configured to be coupled to a low-pressure fuel pump. The camshaft may be received and secured within a central bore of the body for rotatable movement within the central bore. A coupling end of the camshaft may be configured to be coupled to a drive shaft of the low-pressure fuel pump. In an example, the coupling end of the camshaft may be received within a press-fit assembly. In an example, the press-fit assembly may include a sleeve positioned around an outer surface of a bushing, the sleeve being configured to receive the coupling end of the camshaft. The protrusion may include at least one fastener boss configured to receive a fastener to coupled the low-pressure fuel pump to the high-pressure fuel pump assembly.

[0011] In some such examples, a protrusion may be formed at the rear end of the body to reduce thermal stress that could cause geometric deformation at the protrusion within the engine temperature operating conditions. In one example, the protrusion may be formed above a pressure zone of the body, where a press-fit assembly presses against the inner surface of the protrusion. In another example, the diameter of the protrusion is four times its length.

[0012] Examples of this disclosure include a housing for a high-pressure fuel pump configured to be coupled to a low-pressure fuel pump. The housing may include a body and a protrusion. The body may have a front end, a rear end opposite the front end, a central bore, and at least one cylinder extending from the central bore. The rear end may be configured to be coupled to the low-pressure fuel pump. The central bore may be configured to receive and retain a camshaft such that the camshaft is rotatably movable within the central bore and operable to periodically actuate a plunger disposed within the at least one cylinder. The protrusion may be generally annular in shape. The protrusion may include at least one fastener boss configured to receive a fastener to coupled the low-pressure fuel pump to the high-pressure fuel pump. The protrusion may be formed at the rear end of the body to reduce thermal stress that causes geometric deformation at the protrusion within the engine temperature operating conditions.

[0013] In some such examples, a protrusion may be formed above a pressure zone of the body, at which a press-fit assembly presses against the inner surface of the protrusion. The press-fit assembly may include a sleeve positioned around the outer surface of the bushing, the sleeve being configured to receive a connector end of a camshaft. The connector end of the camshaft may be received within the press-fit assembly. In examples, the protrusion may include at least one cutout forming part of at least one fastener boss. The at least one cutout may extend from the outer circumferential wall of the protrusion to a sidewall of the protrusion. The outer surface portion of at least one fastener boss may generally follow the contour of the outer circumferential wall of the protrusion and is positioned at a lower portion of the protrusion to avoid a connector positioned at the lower portion of the protrusion. Attached Figure Description

[0014] The above and other features of this disclosure, and the ways in which they are obtained, will become more apparent and will provide a better understanding of the disclosure itself, in conjunction with the following description of embodiments thereof, taken in conjunction with the accompanying drawings:

[0015] Figure 1A A perspective view of a high-pressure fuel pump assembly according to various aspects of this disclosure;

[0016] Figure 1B A side elevation view of the housing of a high-pressure fuel pump assembly according to various aspects of this disclosure;

[0017] Figure 1C In accordance with the various aspects of this disclosure Figure 1A A sectional view taken at section AA;

[0018] Figure 2A A perspective view of the housing of a high-pressure fuel pump according to various aspects of this disclosure;

[0019] Figure 2B A rear elevation view of the housing of a high-pressure fuel pump according to various aspects of this disclosure;

[0020] Figure 3A A rear elevation view of the high-pressure fuel pump assembly according to various aspects of this disclosure; and

[0021] Figure 3B A perspective view of the rear end of a high-pressure fuel pump assembly according to various aspects of this disclosure.

[0022] Although the accompanying drawings illustrate embodiments of various features and components according to this disclosure, the drawings are not necessarily drawn to scale and some features may be enlarged to better illustrate and explain this disclosure. The examples set forth herein illustrate embodiments of this disclosure, and such examples should not be construed as limiting the scope of this disclosure in any way. Detailed Implementation

[0023] For the purpose of facilitating understanding of the principles of this disclosure, reference will now be made to the embodiments described below as illustrated in the accompanying drawings. However, it should be understood that this is not intended to limit the scope of the disclosure. This disclosure includes any modifications and further variations to the illustrated apparatus and described methods, as well as further applications of the principles of this disclosure, which would normally occur to those skilled in the art to which this disclosure pertains. Furthermore, the embodiments were chosen for description to enable those of ordinary skill in the art to practice this disclosure.

[0024] Now refer to the attached diagram, Figures 1A to 1C Various views of the high-pressure fuel pump assembly 100 according to various aspects of this disclosure are shown. Figure 1A A perspective view of a high-pressure fuel pump assembly 100 according to various aspects of this disclosure is shown. Figure 1B A side elevation view of the housing 125 of the high-pressure fuel pump assembly 100 according to various aspects of this disclosure is shown. Figure 1C The following are shown in accordance with the aspects of this disclosure. Figure 1A The cross-sectional view taken at section AA. The features of the examples shown in these figures will be discussed in detail below.

[0025] Cam-driven high-pressure fuel pump assemblies have become a common solution for generating high-pressure fuel in common rail systems used in direct-injection internal combustion engines. A camshaft 110 is received and secured within a central bore 120 of a body 122 extending through a housing 125 of the high-pressure fuel pump assembly 100, allowing for rotatable movement within the central bore 120. The camshaft 110 includes a cam 112 that converts the rotational motion of the camshaft 110 into reciprocating motion (e.g., via the elliptical shape of the cam 112). High-pressure fuel pump assemblies (such as high-pressure fuel pump assembly 100) typically include a pumping element, such as a plunger (not shown), that reciprocates within a cylinder 126 extending from the central bore 120. The reciprocating motion of the plunger is typically achieved using a cam follower connected to the plunger, which follows the corresponding cam 112 as the camshaft 110 rotates. Two bushings 130 in the high-pressure fuel pump assembly 100 may be located on the sides of the camshaft 110 to support the camshaft 110 within the central bore 120. Bushing 130 is positioned at the front end 127 of the high-pressure fuel pump assembly 100, and bushing 130 within sleeve 132 is positioned at the rear end 128 of the high-pressure fuel pump assembly 100. The coupling end 116 of camshaft 110 may be configured to be coupled to a drive shaft (not shown) of a low-pressure fuel pump, which is coupled to the rear end 128 of the high-pressure fuel pump assembly 100. The low-pressure fuel pump may be driven by camshaft 110 to supply pressurized fuel to the high-pressure fuel pump assembly 100. In these cases, the operation and assembly of the high-pressure fuel pump assembly 100 may generate complex combined loads and thermal effects (e.g., within the engine operating temperature range), which may impair the operation and reliability of the high-pressure fuel pump assembly 100.

[0026] This disclosure relates to a common rail high-pressure fuel pump assembly for use in an internal combustion engine. More specifically, this document discloses means, assemblies, and methods for reducing load-bearing torsion and increasing the holding force of bushings 130 and sleeves 132 in multi-cylinder and cam-driven high-pressure fuel pump assemblies. According to the principles of this disclosure, a first fuel pump assembly 100 (e.g., a high-pressure fuel pump assembly 100) may include a body 122, a camshaft 110, and a protrusion 150. The body 122 may have a front end 127 and a rear end 128 opposite to the front end 127. As described further herein, the camshaft 110 may be received and secured within a central bore 120 of the body 122 for rotatable movement within the central bore 120. The rear end 128 may be configured to be coupled to a second fuel pump assembly (e.g., a low-pressure fuel pump assembly) (not shown). A coupling end 116 of the camshaft 110 may be configured to be coupled to a drive shaft of the low-pressure fuel pump, for example, at the rear end 128. Various factors (such as combined loads from the attached low-pressure fuel pump and components from the high-pressure fuel pump assembly 100 itself, as well as temperature variations across the range of engine operating conditions) create localized hotspots that pose a risk to the operation and durability of the high-pressure fuel pump.

[0027] In the example, a protrusion 150 may be formed above the pressure zone (“PZ”) of the body 122, and a press-fit assembly 135 is press-fitted into the inner surface 121 of the protrusion 150 at the pressure zone, such as... Figure 1B and Figure 1C As shown. The pressure zone PZ can be defined as part of the fuel pump, and because internal components (e.g., press-fit assembly 135) are press-fitted within the body 122 of the high-pressure fuel pump assembly 100, this portion experiences increased forces (e.g., load-bearing forces). The forces experienced at the pressure zone PZ can be exacerbated by components connected to the high-pressure fuel pump assembly 100 (such as the low-pressure fuel pump), and by harmonics, loads, and a range of operating temperatures experienced by the high-pressure fuel pump assembly 100 and its connected components during engine operation. Specifically, at these range of operating temperatures (e.g., up to about 220 degrees Fahrenheit), geometric deformation can be caused by the elevated temperatures, thereby inducing thermal stress in areas of geometric deformation (e.g., at the pressure zone PZ).

[0028] Bushing 130 and sleeve 132 may be included in press-fit assembly 135 and may engage other components of high-pressure fuel pump assembly 100. In an example, press-fit assembly 135 may include sleeve 132 positioned around the outer surface 131 of bushing 130, the sleeve being configured to receive a connector end 116 of camshaft 110. The connector end 116 of camshaft 110 may be received within press-fit assembly 135, for example, within bushing 130. In this way, press-fit assembly 135 may be a three-shell press-fit assembly 135, including a portion as the body 122 of the outer cylinder, sleeve 132 as the middle cylinder, and bushing 130 as the inner cylinder. Press-fit assembly 135 may be a rear section of high-pressure fuel pump assembly 100, for example, at pressure zone PZ. For this section of high-pressure fuel pump assembly 100, protrusion 150 may mitigate thermal stress, which will even out geometric deformation within the engine temperature operating conditions.

[0029] Figure 2A and Figure 2B Various views of the housing 125 of the high-pressure fuel pump are shown. Figure 2A A perspective view of the housing 125 of a high-pressure fuel pump according to various aspects of this disclosure is shown. Figure 2B A rear elevation view of the housing 125 of a high-pressure fuel pump according to various aspects of this disclosure is shown. Such a high-pressure fuel pump can be used in high-pressure fuel pump assemblies discussed elsewhere herein. Features of the examples shown in these figures will be discussed below.

[0030] The examples shown in these figures may be similar to those described elsewhere herein. For example, a housing 125 for a high-pressure fuel pump may be configured to be coupled to a low-pressure fuel pump and may include a body 122 and a protrusion 150. The body 122 may have a front end 127, a rear end 128 opposite to the front end 127, a central bore 120, and at least one cylinder 126 extending from the central bore 120. In the example, the protrusion 150 may be formed above a pressure zone PZ of the body 122, at which a press-fit assembly press-fits with the inner surface 121 of the protrusion 150. The rear end 128 may be configured to be coupled to the low-pressure fuel pump. The central bore 120 may be configured to receive and retain a camshaft such that the camshaft is rotatably movable within the central bore 120 and operable to periodically actuate a plunger disposed within at least one cylinder 126. The press-fit assembly may optionally include a sleeve positioned around the outer surface of a bushing, the sleeve being configured to receive a coupling end of the camshaft. The coupling end of the camshaft may be received within the press-fit assembly. When assembled, the press-fit assembly can abut against the inner surface of the housing 125 (e.g., the inner surface 121 of the protrusion 150) within the pressure zone PZ.

[0031] In some examples, around the pressure zone PZ, the protrusion 150 can provide improved structural margin and elastic drag to accommodate large circumferential stresses there and reduce distortion due to thermal effects. The protrusion 150 may be formed at the rear end 128 of the body 122 to reduce thermal stresses that cause geometric deformation at the protrusion 150 within the engine temperature operating conditions. For example, the protrusion 150 may have a generally annular shape (e.g., a ring or donut) and may be formed on a portion of the housing 125 (e.g., at the rear end 128). In this way, the protrusion 150 may be defined by a diameter D and a length L. In the example, the diameter D of the protrusion 150 is greater than its length L. For example, the diameter D may be two, three, four, or five times the length L of the protrusion 150, etc. In the example, the length L may be the length of the pressure zone PZ.

[0032] The design of the protrusion 150 can be to balance dimensions and surface features to achieve engineering design standards while controlling geometric deformation that will maintain clearances between components in the high-pressure fuel pump. As noted above, the diameter D and length L of the protrusion 150 can be specified. Alternatively or additionally, the protrusion 150 may include at least one fastener boss 260 configured to receive a fastener (not shown) to (e.g., at housing 125) couple a low-pressure fuel pump to a high-pressure fuel pump. In the example, the outer circumferential wall 252 of the protrusion 150 may be integrally circular. In other examples, as shown here, the outer circumferential wall 252 may be partially circular. In some such examples, the outer circumferential wall 252 of the protrusion 150 may transition into a generally flat portion 254 at the upper portion 251 of the protrusion 150.

[0033] Fastener bosses 260 positioned around protrusion 150 can facilitate coupling of components, such as a low-pressure fuel pump, to a high-pressure fuel pump. The flat portion 254 of protrusion 150 may include one or more fastener cavities 262 positioned within one or more fastener bosses 260, and other portions of protrusion 150 may also include such cavities. Protrusion 150 may include at least one fastener boss 260 configured to receive a fastener for coupling a low-pressure fuel pump to a high-pressure fuel pump. Fastener bosses 260 may include fastener cavities 262 configured to receive fasteners or inserts for coupling components, such as a low-pressure fuel pump, to a high-pressure fuel pump. The number of fastener bosses 260 may correspond to or differ from the number of fastener cavities 262. In the example, at least one fastener boss 260 may have an outer surface portion 264 that generally follows the contour of the outer circumferential wall 252 of the protrusion 150 and may be positioned at the lower portion 255 of the protrusion 150 to avoid the connector 270 positioned at the lower portion 255 of the protrusion 150.

[0034] Cutouts 280 may be arranged around protrusions 150 and may form protruding features, such as fastener bosses 260. In an example, protrusion 150 may include at least one cutout 280 that forms part of at least one fastener boss 260. The at least one cutout 280 may extend from the outer circumferential wall 252 of protrusion 150 to, for example, the sidewall 256 of protrusion 150. In this way, cutout 280 may be in the form of a bevel at the circumferential edge of protrusion 150. In other examples, cutout 280 may be in the form of a recess from the sidewall 256 into protrusion 150. In an example, protrusion 150 may include at least one cutout 280 that forms part of at least one fastener boss 260. In this way, an outer surface portion 264 of the fastener boss may be formed by the cutout. The outer surface portion 264 of at least one fastener boss 260 may generally follow the contour of the outer circumferential wall 252 of protrusion 150. In this way, at least one outer surface portion 264 of the fastener boss 260 can be positioned at the lower portion 255 of the protrusion 150 to avoid the connector 270 positioned at the lower portion 255 of the protrusion 150. The connector 270 can be used to connect the component to a high-pressure fuel pump.

[0035] Figure 3A and Figure 3B Various views of the high-pressure fuel pump assembly 100 with bracket 390 are shown. Figure 3A A side elevation view of the high-pressure fuel pump assembly 100 according to various aspects of this disclosure is shown. Figure 3B A perspective view of the rear end 128 of a high-pressure fuel pump assembly 100 according to various aspects of this disclosure is shown. Features of the examples shown in these figures will be discussed below.

[0036] The examples shown in these figures are similar to those described elsewhere herein. For example, a high-pressure fuel pump assembly 100 may be configured to be coupled to a low-pressure fuel pump and may include a body 122 and a protrusion 150. The body 122 may have a front end 127 and a rear end 128 opposite the front end, and may optionally be configured to be coupled to the low-pressure fuel pump. The protrusion 150 may include at least one fastener boss 260 configured to receive a fastener to coupled the low-pressure fuel pump to the high-pressure fuel pump assembly 100. The protrusion 150 may be formed at the rear end 128 of the body 122 to reduce thermal stress that could cause geometric deformation at the protrusion 150 within the range of engine temperature operating conditions. The protrusion 150 may optionally have a generally annular shape and may optionally be formed above a pressure zone PZ of the body 122, where a press-fit assembly presses against the inner surface 121 of the protrusion 150. The diameter D of the protrusion 150 may be greater than its length L (e.g., about two, three, four, or five times). In the example, at least one outer surface portion 264 of the fastener boss 260 may generally follow the contour of the outer circumferential wall 252 of the protrusion 150. In the example, the protrusion 150 may include at least one cutout 280 that forms part of at least one fastener boss 260. In the example, at least one cutout 280 may extend from the outer circumferential wall 252 of the protrusion 150 to the sidewall 256 of the protrusion 150.

[0037] Other components (including the low-pressure fuel pump or others) (e.g., bracket 390) may also be coupled to the high-pressure fuel pump assembly 100. In an example, at least one fastener boss 260 may be positioned at the lower portion 255 of the protrusion 150 to circumvent the connector 270 positioned at the lower portion 255 of the protrusion 150. In some such examples, the connector 270 includes a connector portion 272 configured to engage the bracket 390 to the protrusion 150. In these cases, the connector portion 272 may be in the form of a protrusion from the protrusion 150 and may include one or more fastener recesses configured to receive fasteners for engaging the bracket 390 to the connector portion 272.

[0038] The connecting lines shown in the various figures included herein are intended to represent exemplary functional relationships and / or physical connections between various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in a real system. However, the benefits, advantages, problem solutions, and any elements that make any benefit, advantage, or solution appear or become more significant should not be construed as critical, essential, or necessary features or elements. Therefore, the scope is limited only by the appended claims, where references to singular elements are not intended to mean "one and only one," but rather "one or more," unless explicitly stated otherwise. Furthermore, where phrases like "at least one of A, B, or C" are used in the claims, it is intended that such phrases be interpreted as meaning that A may exist alone in an embodiment, B may exist alone in an embodiment, C may exist alone in an embodiment, or any combination of elements A, B, or C may exist in a single embodiment; for example, A and B, A and C, B and C, or A and B and C.

[0039] In the detailed description herein, references such as "an embodiment," "an embodiment," and "an exemplary embodiment" indicate that the described embodiment may include a particular feature, structure, or characteristic; however, each embodiment may not necessarily include the stated particular feature, structure, or characteristic. Furthermore, such wording does not necessarily refer to the same embodiment. Moreover, when a particular feature, structure, or characteristic is described in connection with an embodiment, it should be assumed that, whether explicitly described or not, causing such feature, structure, or characteristic to work in combination with other embodiments is within the knowledge of one skilled in the art who benefits from this disclosure. After reading the description, those skilled in the art will understand how to implement this disclosure in alternative embodiments.

[0040] Furthermore, none of the elements, components, or method steps in this disclosure are intended to be exclusive to the public, regardless of whether they are expressly recited in the claims. No element of any claim herein shall be construed under the provisions of 35 U.S.SC 112(f) unless the element is expressly recited using the phrase “means for…”. As used herein, the terms “comprising,” “including,” or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article of manufacture, or apparatus that comprises a list of elements includes not only those elements but may include other elements not expressly listed or inherent to such process, method, article of manufacture, or apparatus.

[0041] While the embodiments have been described as having exemplary designs, further modifications to this disclosure are possible within the spirit and scope of this disclosure. Therefore, this application is intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Furthermore, this application is intended to cover such deviations from this disclosure as those within the scope of known or customary practice in the art to which this invention pertains.

Claims

1. A high-pressure fuel pump configured to be coupled to a low-pressure fuel pump, the high-pressure fuel pump comprising: The body has a front end and a rear end opposite to the front end, the rear end being configured to be coupled to the low-pressure fuel pump; as well as A protrusion formed above the pressure zone of the body, the protrusion including at least one fastener boss configured to receive a fastener to connect the low-pressure fuel pump to the high-pressure fuel pump, and the protrusion being formed at the rear end of the body to reduce thermal stress at the protrusion that causes geometric deformation within the engine temperature operating conditions.

2. The high-pressure fuel pump of claim 1, wherein the protrusion is formed above the pressure zone of the body, and the press-fit assembly is press-fitted into the inner surface of the protrusion at the pressure zone.

3. The high-pressure fuel pump of claim 1, wherein the diameter of the protrusion is four times its length.

4. The high-pressure fuel pump of claim 1, wherein the outer surface portion of the at least one fastener boss generally follows the contour of the outer circumferential wall of the protrusion.

5. The high-pressure fuel pump of claim 1, wherein the at least one fastener boss is positioned at the lower portion of the protrusion to avoid a connector positioned at the lower portion of the protrusion.

6. The high-pressure fuel pump of claim 5, wherein the connector includes a connector portion configured to attach a bracket to the protrusion.

7. The high-pressure fuel pump of claim 1, wherein the protrusion includes at least one cut, the at least one cut forming part of the at least one fastener boss.

8. The high-pressure fuel pump of claim 7, wherein the at least one cut extends from the outer circumferential wall of the protrusion to the side wall of the protrusion.

9. The high-pressure fuel pump of claim 1, wherein the protrusion has a generally annular shape.

10. The high-pressure fuel pump of claim 1, wherein the outer circumferential wall of the protrusion transitions into a generally flat portion at the upper portion of the protrusion.

11. A high-pressure fuel pump assembly, comprising: The body has a front end and a rear end opposite to the front end, the rear end being configured to be coupled to a low-pressure fuel pump; A camshaft is received and fixed within a central bore of the body so as to be rotatably movable within the central bore, and the coupling end of the camshaft is configured to be coupled to the drive shaft of the low-pressure fuel pump. as well as A protrusion formed above the pressure zone of the body, the protrusion including at least one fastener boss configured to receive a fastener to connect the low-pressure fuel pump to the high-pressure fuel pump assembly, and the protrusion being formed at the rear end of the body to reduce thermal stress at the protrusion that causes geometric deformation within the engine temperature operating conditions.

12. The high-pressure fuel pump assembly of claim 11, wherein the protrusion is formed above the pressure zone of the body, and the press-fit assembly is press-fitted into the inner surface of the protrusion at the pressure zone.

13. The high-pressure fuel pump assembly of claim 12, wherein the coupling end of the camshaft is received within the press-fit assembly.

14. The high-pressure fuel pump assembly of claim 12, wherein the press-fit assembly includes a sleeve positioned around the outer surface of the bushing, the sleeve being configured to receive a coupling end of the camshaft.

15. The high-pressure fuel pump assembly of claim 11, wherein the diameter of the protrusion is four times its length.

16. The high-pressure fuel pump assembly of claim 11, wherein the outer surface portion of the at least one fastener boss generally follows the contour of the outer circumferential wall of the protrusion and is positioned at the lower portion of the protrusion to avoid a connector positioned at the lower portion of the protrusion.

17. The high-pressure fuel pump assembly of claim 11, wherein the protrusion includes at least one cut that forms part of the at least one fastener boss, and wherein the at least one cut extends from the outer circumferential wall of the protrusion to the sidewall of the boss.

18. A housing for a high-pressure fuel pump configured to be coupled to a low-pressure fuel pump, the housing comprising: The body has a front end, a rear end opposite to the front end, a central bore, and at least one cylinder extending from the central bore, the rear end being configured to be coupled to the low-pressure fuel pump, and the central bore being configured to receive and fix a camshaft such that the camshaft is rotatably movable within the central bore and operable to periodically actuate a plunger disposed within the at least one cylinder. as well as A protrusion formed above the pressure zone of the body, the protrusion being generally annular in shape, includes at least one fastener boss configured to receive a fastener to connect the low-pressure fuel pump to the high-pressure fuel pump, and the protrusion is formed at the rear end of the body such that thermal stress causing geometric deformation at the protrusion is reduced within the engine temperature operating conditions.

19. The housing of claim 18, wherein the protrusion is formed above the pressure zone of the body, and a press-fit assembly is press-fitted into the inner surface of the protrusion at the pressure zone, wherein the press-fit assembly includes a sleeve positioned around the outer surface of the bushing, the sleeve being configured to receive a connector end of the camshaft, and wherein the connector end of the camshaft is received within the press-fit assembly.

20. The housing of claim 18, wherein the protrusion includes at least one cutout forming part of the at least one fastener boss, wherein the at least one cutout extends from the outer circumferential wall of the protrusion to the sidewall of the protrusion, and wherein the outer surface portion of the at least one fastener boss substantially follows the contour of the outer circumferential wall of the protrusion and is positioned at a lower portion of the protrusion to avoid a connector positioned at the lower portion of the protrusion.

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