Constant-flowrate fuel pump

Abstract

A constant-flowrate fuel pump, comprising a pump body, a driving assembly and, arranged on the pump body, a fuel inlet pipe and fuel outlet pipes. The pump body is provided with a chamber, the driving assembly being arranged in the chamber and used for sucking fuel into the chamber or discharging the fuel from the chamber. A first end of the fuel inlet pipe is provided with a fuel inlet for the fuel to flow in; the wall of the fuel inlet pipe is provided with a fuel inlet hole leading to the chamber, the fuel entering the fuel inlet pipe via the fuel inlet and being sucked into the chamber via the fuel inlet hole. The fuel outlet pipes are arranged on a side of the fuel inlet pipe and are spaced apart from each other; a first end of each fuel outlet pipe is provided with an fuel outlet for the fuel to flow out; the wall of each fuel outlet pipe is provided with an fuel outlet hole leading to the chamber; the fuel in the chamber is discharged into the fuel outlet pipes via the fuel outlet holes, and is discharged by means of the fuel outlets of the fuel outlet pipes. On the basis of a target flowrate of the fuel pump, the diameter of the fuel inlet hole is less than a preset diameter, the target flowrate and the preset diameter satisfying a relationship between flowrates and diameters of the fuel inlet hole.

Description

A constant flow fuel pump Technical Field

[0001] This disclosure relates to, but is not limited to, a constant flow fuel pump. Background Technology

[0002] A fuel pump is a mechanical device used in a fuel supply system to draw fuel from the fuel tank and transport the drawn fuel to the engine through a fuel pipeline at a certain working pressure to provide fuel for the engine.

[0003] Currently, during the operation of a fuel pump, the flow rate changes linearly with its rotational speed, making it difficult to control the flow rate at high speeds. Summary of the Invention

[0004] The following is an overview of the subject matter described in detail in this disclosure. This overview is not intended to limit the scope of the claims.

[0005] This disclosure provides a constant flow fuel pump, the constant flow fuel pump comprising:

[0006] Pump body, wherein the pump body is provided with a cavity;

[0007] A drive assembly, disposed in the cavity, is used to draw fuel into the cavity or discharge fuel from the cavity;

[0008] An oil inlet pipe is provided on the pump body; the first end of the oil inlet pipe is provided with an oil inlet port for fuel to flow in; the pipe wall of the oil inlet pipe is provided with an oil inlet hole that communicates with the cavity, and the fuel enters the oil inlet pipe through the oil inlet port and is drawn into the cavity through the oil inlet hole;

[0009] An oil outlet pipe is provided on the pump body and spaced apart on one side of the oil inlet pipe; the first end of the oil inlet pipe is provided with an oil outlet for the fuel to flow out; the pipe wall of the oil outlet pipe is provided with an oil outlet hole that communicates with the cavity, and the fuel in the cavity is discharged into the oil outlet pipe through the oil outlet hole and discharged through the oil outlet of the oil outlet pipe.

[0010] Based on the target flow rate of the fuel pump, the diameter of the fuel inlet is smaller than a preset diameter;

[0011] The target flow rate and the preset diameter satisfy the relationship between target flow rate and preset diameter.

[0012] In some embodiments, the ratio of the diameter of the oil outlet hole to the diameter of the oil inlet hole is 1.2-1.5:1.

[0013] In some embodiments, the pump body is provided with a first valve hole and a second valve hole communicating with the first valve hole, wherein the first valve hole and the second valve hole form a stepped groove;

[0014] The first end of the first valve hole is connected to the second end of the oil outlet pipe, and the second end of the first valve hole is connected to the second end of the oil inlet pipe;

[0015] Safety valve assemblies are provided in the first valve port and the second valve port, and the safety valve assemblies are used to limit the output pressure of the oil outlet.

[0016] In some embodiments, the pump body is provided with a connection hole, the first end of the connection hole is connected to the second end of the first valve hole, the second end of the connection hole is connected to the second end of the oil inlet pipe, and the diameter of the connection hole is smaller than the diameter of the oil inlet pipe.

[0017] In some embodiments, the safety valve assembly includes:

[0018] A screw plug is disposed at the end of the second valve hole opposite to the first valve hole;

[0019] An elastic element is disposed in the first valve hole and the second valve hole, and the first end of the elastic element is connected to the screw plug;

[0020] A sphere, the sphere being connected to the second end of the elastic element, and the sphere being slidably connected to the first valve hole;

[0021] When the output pressure of the oil outlet is greater than a preset threshold, the ball moves from the first end of the first valve hole to the second end of the first valve hole, and the elastic element is compressed.

[0022] When the output pressure of the oil outlet is less than the preset threshold, the elastic element resets, causing the ball to move from the second end of the first valve hole to the first end of the first valve hole.

[0023] In some embodiments, a plurality of drainage grooves are distributed circumferentially on the wall of the first valve hole, and each drainage groove extends along the axial direction or helical direction of the first valve hole.

[0024] In some embodiments, the plurality of drainage channels are symmetrically distributed around the axial direction of the first valve hole.

[0025] In some embodiments, a ball seat is provided at the first end of the first valve body, and the ball is capable of abutting against the end of the ball seat away from the oil outlet pipe.

[0026] In some embodiments, the fuel pump further includes a cover plate disposed on the pump body, the cover plate being disposed on the side of the cavity opposite to the fuel inlet pipe and the fuel outlet pipe.

[0027] In some embodiments, the fuel pump further includes a one-way valve disposed on the cover plate, the one-way valve being located on the side of the cavity opposite to the fuel inlet pipe and the fuel outlet pipe, for controlling the flow of fuel from the fuel pump to the engine.

[0028] The constant flow fuel pump disclosed herein adjusts the suction negative pressure by making the diameter of the fuel inlet hole smaller than a preset diameter according to the target flow rate of the fuel pump. When the target flow rate is low, the fuel inlet hole will not restrict the flow rate of the fuel pump. However, when the target flow rate is high, the fuel suction volume can be controlled through the fuel inlet hole to limit the high-speed flow rate, thereby achieving constant flow control of the fuel pump.

[0029] After reading and understanding the accompanying diagrams and detailed descriptions, the other aspects can be understood. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of these embodiments. In these drawings, similar reference numerals are used to denote similar elements. The drawings described below are some embodiments of the present disclosure, but not all embodiments. Other drawings will be readily available to those skilled in the art based on these drawings without inventive effort.

[0031] Figure 1 is a schematic diagram of the structure of a constant flow fuel pump according to an exemplary embodiment.

[0032] Figure 2 is a schematic diagram of the structure of the cavity of a constant flow fuel pump according to an exemplary embodiment.

[0033] Figure 3 is a schematic cross-sectional view of the inlet pipe of a constant flow fuel pump according to an exemplary embodiment.

[0034] Figure 4 is a cross-sectional schematic diagram of the check valve of a constant flow fuel pump according to an exemplary embodiment.

[0035] Figure label:

[0036] 1. Pump body; 11. Cavity; 12. First valve hole; 13. Second valve hole; 14. Connecting hole; 2. Drive assembly; 21. Drive wheel; 22. Driven wheel; 23. Power shaft; 3. Oil inlet pipe; 31. Oil inlet port; 32. Oil inlet hole; 4. Oil outlet pipe; 41. Oil outlet port; 42. Oil outlet hole; 5. Safety valve assembly; 51. Plug; 52. Elastic element; 53. Ball; 54. Drainage groove; 55. Ball seat; 6. Cover plate; 7. Check valve. Detailed Implementation

[0037] The technical solutions of the disclosed embodiments will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this disclosure can be arbitrarily combined with each other.

[0038] In related technologies, fuel pumps are difficult to control at a constant flow rate, causing the flow rate to increase linearly with engine speed, which in turn leads to increased energy consumption. Although constant flow control valves can be used to control flow, current constant flow control valves are mainly used in power steering pumps, where flow control is achieved through clearance fitting. Fuel pumps primarily use diesel fuel. Due to diesel's low viscosity, fuel leakage occurs through the clearance when using a constant flow control valve for flow control. Therefore, the practical application of constant flow control valves in fuel pumps is not ideal.

[0039] To address the aforementioned technical problems, an exemplary embodiment of this disclosure provides a constant flow fuel pump, as shown in Figure 1. Figure 1 shows a structural schematic diagram of the constant flow fuel pump provided according to an exemplary embodiment of this disclosure. Figure 2 shows a structural schematic diagram of the cavity of the constant flow fuel pump provided according to an exemplary embodiment of this disclosure. Figure 3 shows a cross-sectional structural schematic diagram of the fuel inlet pipe provided according to an exemplary embodiment of this disclosure. Figure 4 shows a cross-sectional structural schematic diagram of the one-way valve provided according to an exemplary embodiment of this disclosure. The structure of the constant flow fuel pump will be described below with reference to Figures 1-4.

[0040] As shown in Figures 1-3, an exemplary embodiment of this disclosure provides a constant flow fuel pump, including a pump body 1, a drive assembly 2, an inlet pipe 3 and an outlet pipe 4 disposed on the pump body 1; the pump body 1 is provided with a cavity 11, and the drive assembly 2 is disposed in the cavity 11 for drawing fuel into the cavity 11 or discharging fuel from the cavity 11; the first end of the inlet pipe 3 is provided with an inlet port 31 for fuel to flow in; the pipe wall of the inlet pipe 3 is provided with an inlet hole 32 communicating with the cavity 11, and fuel enters the inlet pipe 3 through the inlet port 31. The fuel is drawn into the cavity 11 through the fuel inlet 32; the fuel outlet pipe 4 is spaced apart on one side of the fuel inlet pipe 3, and the first end of the fuel inlet pipe 3 is provided with a fuel outlet 41 for fuel to flow out; the wall of the fuel outlet pipe 4 is provided with a fuel outlet 42 that communicates with the cavity 11, and the fuel in the cavity 11 is discharged into the fuel outlet pipe 4 through the fuel outlet 42 and discharged through the fuel outlet 41; according to the target flow rate of the fuel pump, the diameter of the fuel inlet 32 ​​is smaller than the preset diameter; the target flow rate and the preset diameter satisfy the relationship between flow rate and fuel inlet diameter.

[0041] In this embodiment, fuel is drawn into the fuel inlet pipe 3 through the fuel inlet 31 via the drive component 2, and then into the chamber 11 through the fuel inlet hole 32. The fuel is then discharged into the fuel inlet pipe 3 through the fuel outlet hole 42 and discharged through the fuel outlet hole 41 of the fuel outlet pipe 4. This embodiment adjusts the suction negative pressure by adjusting the diameter of the fuel inlet hole 32 to be smaller than a preset diameter. At low operating flow rates, the fuel inlet hole 32 does not restrict the fuel pump flow rate; however, at high operating flow rates, the fuel inlet hole 32 controls the amount of fuel drawn in to limit the high-speed flow, thereby achieving constant flow control of the fuel pump.

[0042] The diameter of the fuel inlet hole 32 cannot be too low, otherwise it will affect the normal operation of the fuel pump. For example, the ratio of the diameter of the fuel inlet hole 32 to the preset diameter can be 0.80-0.96:1. For example, the ratio of the diameter of the fuel inlet hole 32 to the preset diameter can be 0.80:1, 0.85:1, 0.90:1, or 0.96:1. The ratio of the diameter of the fuel inlet hole 32 to the preset diameter can also be any ratio between the exemplary ratios. For example, the ratio of the diameter of the fuel inlet hole 32 to the preset diameter can also be any ratio between 0.85-0.90:1.

[0043] The relationship between the target flow rate and the preset diameter can be expressed by the following formula (Ⅰ):

[0044] In the formula:

[0045] Q: Oil inlet flow rate, m 3 / s;

[0046] C d : Inlet flow coefficient;

[0047] A0: Cross-sectional area of ​​the oil inlet hole, m 2 ;

[0048] ΔP: Pressure difference across the oil inlet, Pa;

[0049] ρ: density of the fluid, kg / m³ 3 ;

[0050] d: Preset diameter, m.

[0051] The diameter of the oil inlet can be set according to the relationship between the target flow rate and the preset diameter.

[0052] For example, the preset diameter d = 5 × 10 -3 m; Flow coefficient C d =0.60; Pressure difference ΔP = 50 × 10 3 Pa; diesel density ρ = 835 kg / m³ 3 ;calculate The target flow rate Q is converted to 7.73 L / min. Therefore, when the target flow rate is 7.73 L / min, the diameter of the oil inlet can be less than 5 × 10⁻⁶. -3 For example, the diameter of the oil inlet hole can be 4.5 × 10 m. -3 m.

[0053] In some embodiments, the drive assembly 2 includes a drive wheel 21, a driven wheel 22 meshing with the drive wheel 21, and a power shaft 23 driving the drive wheel 21 to rotate. The power shaft 23 can be connected to an external power assembly. Both the drive wheel 21 and the driven wheel 22 are disposed in a cavity 11. The cavity 11 is divided into an oil inlet chamber and an oil outlet chamber by the drive wheel 21 and the driven wheel 22. An oil inlet hole 32 is located in the oil inlet chamber, and an oil outlet hole 42 is located in the oil outlet chamber. The working principle of the drive assembly 2 is as follows: the external power assembly drives the drive wheel 21 to rotate through the power shaft 23. The drive wheel 21 and the driven wheel 22 mesh and operate in the cavity 11. When the drive wheel 21 and the driven wheel 22 rotate and unfold, the volume of the oil inlet chamber increases, creating a vacuum and drawing in oil. When the drive wheel 21 and the driven wheel 22 rotate and mesh, the volume of the oil outlet chamber decreases to discharge oil. Through the continuous operation of the drive wheel 21 and the driven wheel 22, fuel can be drawn in or discharged, thereby realizing the function of a fuel pump.

[0054] In some embodiments, the ratio of the diameter of the oil outlet 42 to the diameter of the oil inlet 32 ​​is 1.2-1.5:1.

[0055] In this embodiment, by adjusting the relationship between the diameter of the oil outlet hole 42 and the diameter of the oil inlet hole 32, a certain back pressure can be generated in the oil outlet chamber, making it easier for fuel to enter the friction pair between the gear and the pump body 1 for lubrication, thereby obtaining a better lubrication effect and improving service life. For example, the ratio of the diameter of the oil outlet hole 42 to the diameter of the oil inlet hole 32 is 1.20:1, 1.26:1, 1.30:1, 1.42:1, or 1.50:1. The ratio of the diameter of the oil outlet hole 42 to the diameter of the oil inlet hole 32 can also be any ratio among the exemplary ratios; for example, the ratio of the diameter of the oil outlet hole 42 to the diameter of the oil inlet hole 32 can also be any ratio between 1.26 and 1.42:1.

[0056] In some embodiments, the pump body 1 is provided with a first valve hole 12 and a second valve hole 13 connected to the first valve hole 12, and the first valve hole 12 and the second valve hole 13 form a stepped groove; the first end of the first valve hole 12 is connected to the second end of the oil outlet pipe 4, and the second end of the first valve hole 12 is connected to the second end of the oil inlet pipe 3; a safety valve assembly 5 is provided in the first valve hole 12 and the second valve hole 13, and the safety valve assembly 5 is used to limit the output pressure of the oil outlet 41.

[0057] In this embodiment, the drive component 2 can realize the intake or discharge of fuel; when the load pressure of the fuel pump outlet 41 exceeds the set value, the pressure of the outlet 41 can be relieved by the action of the safety valve component 5, so as to limit the output pressure of the outlet 41, so that the fuel pump and the engine are maintained within a safe working pressure range, ensuring the safe operation of the fuel system.

[0058] In some embodiments, the pump body 1 is provided with a connection hole 14, the first end of the connection hole 14 is connected to the second end of the first valve hole 12, the second end of the connection hole 14 is connected to the second end of the oil inlet pipe 3, and the diameter of the connection hole 14 is smaller than the diameter of the oil inlet pipe 3.

[0059] In this embodiment, the connecting hole 14 and the oil inlet pipe 3 can form a stepped hole. Since the diameter of the connecting hole 14 is smaller than the diameter of the oil inlet pipe 3, the oil inlet resistance can be reduced, the fuel intake efficiency can be improved, and the working performance of the fuel pump can be made more stable.

[0060] In some embodiments, the safety valve assembly 5 includes a plug 51, an elastic element 52, and a ball 53. The plug 51 is disposed at one end of the second valve hole 13 away from the first valve hole 12. The elastic element 52 is disposed in the first valve hole 12 and the second valve hole 13, and the first end of the elastic element 52 is connected to the plug 51. The ball 53 is connected to the second end of the elastic element 52 and is slidably connected to the first valve hole 12. When the output pressure of the oil outlet 41 is greater than a preset threshold, the ball 53 moves from the first end of the first valve hole 12 to the second end of the first valve hole 12 (i.e., from bottom to top in FIG. 3), and the elastic element 52 is compressed. When the output pressure of the oil outlet 41 is less than the preset threshold, the elastic element 52 resets, causing the ball 53 to move from the second end of the first valve hole 12 to the first end of the first valve hole 12 (i.e., from top to bottom in FIG. 3).

[0061] In this embodiment, the reciprocating motion of the ball 53 between the first valve hole 12 and the second valve hole 13 can effectively adjust the output pressure of the oil outlet 42. The ball 53 can be a steel ball, the elastic element 52 can be a spring, and the preset threshold can be the spring force, i.e., the minimum force required for the spring to deform. The elastic element 52 and the screw plug 51 can be fixedly connected or abutted, and the ball 53 and the elastic element 52 can also be fixedly connected or abutted.

[0062] In some embodiments, a plurality of drainage grooves 54 are distributed circumferentially on the wall of the first valve hole 12, and each drainage groove 54 extends along the axial direction or the spiral direction of the first valve hole 12.

[0063] In this embodiment, when the ball 53 moves to the second valve hole 13, fuel can overflow through the guide groove 54 to relieve the pressure at the oil outlet 41. The guide groove 54 can be arranged along the axial direction of the first valve hole 12 or along the spiral direction of the first valve hole 12.

[0064] In some embodiments, a plurality of drainage channels 54 are symmetrically distributed around the axial direction of the first valve hole 12.

[0065] In this embodiment, multiple drainage channels 54 are symmetrically distributed around the axis of the first valve hole 12, which can improve the uniformity of pressure relief at various points. The number of drainage channels 54 is not limited; it can be one, two, etc. For example, in Figure 3, there are four drainage channels 54.

[0066] In some embodiments, a ball seat 55 is provided at the first end of the first valve body, and a ball 53 can abut against the end of the ball seat 55 away from the oil outlet pipe 4.

[0067] In this embodiment, the ball seat 55 can limit the ball 53, preventing the ball 53 from detaching from the first valve hole 12 during the movement of the first valve hole 12.

[0068] In some embodiments, the fuel pump further includes a cover plate 6 disposed on the pump body 1, the cover plate 6 being disposed on the side of the cavity 11 opposite to the fuel inlet pipe 3 and the fuel outlet pipe 4.

[0069] In this embodiment, the cover plate 6 can seal the cavity 11. This disclosure controls the high-speed flow rate by reducing the diameter of the oil inlet hole 32, thereby increasing the suction negative pressure and limiting the high-speed oil intake. However, the increased suction negative pressure can also cause cavitation inside the cavity 11 and cover plate 6. Conventional aluminum alloy pump bodies 1 and bearings are insufficient to meet the requirements affecting the service life of the fuel pump. Therefore, in this embodiment, hard anodizing treatment can be performed on the surfaces of the cavity 11 and cover plate 6 to form an oxide wear-resistant layer, thereby improving the surface hardness of the cavity 11 and cover plate 6. In related technologies, 3-4 needle roller bearings are typically used to reduce wear when the drive wheel 21 directly contacts the pump body 1. In this embodiment, because the surface of the cavity 11 is hard anodized, the wear resistance of the pump body 1 is increased, eliminating the need for needle roller bearings. This allows the drive wheel 21 and driven wheel 22 to directly contact the wear-resistant layer of the cavity 11, thereby reducing manufacturing costs. After testing, the fuel pump in this embodiment can meet the 2500-hour pressure holding durability test, which reduces product manufacturing costs while increasing the service life of the fuel pump.

[0070] As shown in Figure 4, in some embodiments, the fuel pump also includes a one-way valve 7 disposed on the cover plate 6. The one-way valve 7 is located on the side of the cavity 11 away from the fuel inlet pipe 3 and the fuel outlet pipe 4, and is used to control the flow of fuel from the fuel pump to the engine.

[0071] In this embodiment, the one-way valve 7 can be set above the oil outlet pipe 4. By setting the one-way valve 7, fuel backflow can be prevented, so that fuel can only flow from the fuel pump to the generator. It can also keep the pressure in the fuel pump stable, so as to ensure the continuity and stability of fuel supply.

[0072] In some embodiments, the exemplary embodiments of this disclosure provide a working principle of a constant flow fuel pump:

[0073] The diameters of the inlet hole 32 and the outlet hole 42 are set according to the target flow rate. An external power unit drives the drive wheel 21 to rotate via the power shaft 23. The drive wheel 21 and the driven wheel 22 mesh within the cavity 11. As the drive wheel 21 and driven wheel 22 rotate and unfold, the volume of the inlet chamber increases, creating a vacuum that draws in fuel. Fuel is drawn into the inlet pipe 3 through the inlet port 31 and then into the cavity 11 through the inlet hole 32. As the drive wheel 21 and driven wheel 22 rotate and mesh, the volume of the outlet chamber decreases, and fuel is discharged into the inlet pipe 3 through the outlet hole 42 and out through the outlet port 41 of the outlet pipe 4. When the fuel pump is running at high speed, because the diameter of the inlet hole 32 is smaller than the preset diameter, the amount of fuel drawn in can be limited to restrict the high-speed flow rate, thus achieving constant flow control of the fuel pump.

[0074] When the output pressure of the fuel pump outlet 41 exceeds the preset threshold, the ball 53 moves from the first end of the first valve hole 12 to the second end of the first valve hole 12, the elastic element 52 is compressed, and the ball 53 moves to the second valve hole 13. Fuel can overflow through the drain groove 54 to relieve the pressure of the outlet 41. When the output pressure of the outlet 41 is less than the preset threshold, the elastic element 52 resets, causing the ball 53 to move from the second end of the first valve hole 12 to the first end of the first valve hole 12. By the reciprocating motion of the ball 53 between the first valve hole 12 and the second valve hole 13, the output pressure of the outlet 42 can be effectively adjusted.

[0075] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0076] In the description of this specification, references to the terms "embodiment," "exemplary embodiment," "some implementation," "illustrated implementation," "example," etc., refer to specific features, structures, materials, or characteristics described in connection with an implementation or example that are included in at least one implementation or example of this disclosure.

[0077] In this specification, the illustrative expressions of the terms used do not necessarily refer to the same implementation or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more implementations or examples.

[0078] In the description of this disclosure, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0079] It is understood that the terms "first," "second," etc., as used in this disclosure may be used to describe various structures, but these structures are not limited by these terms. These terms are only used to distinguish one structure from another.

[0080] In one or more accompanying drawings, the same elements are represented by similar reference numerals. For clarity, many parts in the drawings are not drawn to scale. Furthermore, certain well-known parts may not be shown. For simplicity, a structure obtained after several steps may be depicted in a single drawing. Many specific details of this disclosure, such as the structure, materials, dimensions, processing methods, and techniques of the devices, are described below to provide a clearer understanding of the disclosure. However, as those skilled in the art will understand, this disclosure may be implemented without adhering to these specific details.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure. Industrial applicability

[0082] The constant flow fuel pump disclosed herein adjusts the suction negative pressure by adjusting the diameter of the fuel inlet hole to be smaller than a preset diameter. When the target flow rate is low, the fuel inlet hole does not restrict the flow rate of the fuel pump. However, when the target flow rate is high, the fuel intake can be controlled through the fuel inlet hole to limit the high-speed flow rate, thereby achieving constant flow control of the fuel pump.

Claims

1. A constant flow fuel pump, the constant flow fuel pump comprising: Pump body, wherein the pump body is provided with a cavity; A drive assembly, disposed in the cavity, is used to draw fuel into the cavity or discharge fuel from the cavity; An oil inlet pipe is provided on the pump body; the first end of the oil inlet pipe is provided with an oil inlet port for fuel to flow in; the pipe wall of the oil inlet pipe is provided with an oil inlet hole that communicates with the cavity, and the fuel enters the oil inlet pipe through the oil inlet port and is drawn into the cavity through the oil inlet hole; An oil outlet pipe is provided on the pump body and spaced apart on one side of the oil inlet pipe; the first end of the oil inlet pipe is provided with an oil outlet for the fuel to flow out; the pipe wall of the oil outlet pipe is provided with an oil outlet hole that communicates with the cavity, and the fuel in the cavity is discharged into the oil outlet pipe through the oil outlet hole and discharged through the oil outlet of the oil outlet pipe. Based on the target flow rate of the fuel pump, the diameter of the fuel inlet is smaller than a preset diameter; The target flow rate and the preset diameter satisfy the relationship between target flow rate and preset diameter.

2. The constant flow fuel pump of claim 1, wherein, The ratio of the diameter of the oil outlet hole to the diameter of the oil inlet hole is 1.2-1.5:

1.

3. The constant flow fuel pump of claim 1, wherein, The pump body is provided with a first valve hole and a second valve hole that communicates with the first valve hole, and the first valve hole and the second valve hole form a stepped groove. The first end of the first valve hole is connected to the second end of the oil outlet pipe, and the second end of the first valve hole is connected to the second end of the oil inlet pipe; Safety valve assemblies are provided in the first valve port and the second valve port, and the safety valve assemblies are used to limit the output pressure of the oil outlet.

4. The constant flow fuel pump of claim 3, wherein, The pump body is provided with a connection hole. The first end of the connection hole is connected to the second end of the first valve hole, and the second end of the connection hole is connected to the second end of the oil inlet pipe. The diameter of the connection hole is smaller than the diameter of the oil inlet pipe.

5. The constant flow fuel pump of claim 4, wherein, The safety valve assembly includes: A screw plug is disposed at the end of the second valve hole opposite to the first valve hole; An elastic element is disposed in the first valve hole and the second valve hole, and the first end of the elastic element is connected to the screw plug; A sphere, the sphere being connected to the second end of the elastic element, and the sphere being slidably connected to the first valve hole; When the output pressure of the oil outlet is greater than a preset threshold, the ball moves from the first end of the first valve hole to the second end of the first valve hole, and the elastic element is compressed. When the output pressure of the oil outlet is less than the preset threshold, the elastic element resets, causing the ball to move from the second end of the first valve hole to the first end of the first valve hole.

6. The constant flow fuel pump of claim 5, wherein, The first valve hole has multiple drainage grooves distributed circumferentially on its wall, and each drainage groove extends along the axial direction or helical direction of the first valve hole.

7. The constant flow fuel pump of claim 6, wherein, The plurality of drainage channels are symmetrically distributed around the axis of the first valve hole.

8. The constant flow fuel pump of claim 6, wherein, The first valve body has a ball seat at its first end, and the ball can abut against the end of the ball seat away from the oil outlet pipe.

9. The constant flow fuel pump of claim 1, wherein, The fuel pump also includes a cover plate disposed on the pump body, the cover plate being disposed on the side of the cavity opposite to the fuel inlet pipe and the fuel outlet pipe.

10. The constant flow fuel pump of claim 9, wherein, The fuel pump further comprises a one-way valve arranged on the cover plate, which is located on the side of the cavity away from the oil inlet pipe and the oil outlet pipe, and is used for controlling the fuel to flow from the fuel pump to the engine.

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