Fuel pump inlet structure

Abstract

The invention discloses a fuel pump inlet structure, and relates to the technical field of fuel pumps, the fuel pump inlet structure comprises an inlet pipeline arranged on a fuel pump and used for oil circulation, the inlet pipeline is provided with a pressure flow exhaust mechanism for eliminating air in oil in the inlet pipeline to prevent the air binding problem, and the pressure flow exhaust mechanism comprises an annular base; the annular base comprises an integrally-formed inner step part, a conical sealing seat coaxial with the annular base is arranged on the annular base, the conical sealing seat comprises an integrally-formed oblique conical surface, and a conical channel for oil liquid to flow is formed between the inner step part and the oblique conical surface; by means of the Venturi effect and the Bernoulli effect, low pressure is generated at the conical channel, and gas at the bent portion is sucked into the special-shaped sealing base through the connecting pipeline, so that the gas is prevented from entering the pump body, the gas binding phenomenon caused by gas accumulation when the fuel pump sucks oil is effectively avoided, normal work of the fuel pump is guaranteed, and the service life of the fuel pump is prolonged. And the problems of insufficient fuel flow or pressure fluctuation and the like are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of fuel pumps, in particular to a fuel pump inlet structure. Background Art

[0002] The fuel pump is the core component of the fuel system. Its main function is to extract fuel from the fuel tank and deliver it to the engine's fuel injection system or carburetor at a certain pressure. Non-variable displacement fuel pumps achieve fluid delivery by converting the energy of the working fluid into kinetic energy, and then converting the kinetic energy into potential energy including fluid pressure energy. Common non-variable displacement fuel pumps include turbine type and vane type.

[0003] Chinese patent (Announcement No.: CN117345688A), the scheme specifically includes an inlet pipe, a valve seat, a volute, an oil pump port, two guide fins, a support frame, a rotating shaft, an elastic component, and a valve plate. The valve seat is installed on the pump housing of the fuel pump and is located at the inlet of the fuel pump; a support frame is provided on the valve seat, a rotating shaft is installed in the support frame, two valve plates are installed on the rotating shaft, and the valve plates are pressed by elastic components; the oil pump port is installed on the pump core of the fuel pump and inserted into the volute; the guide fin is a radially inward extension structure of the oil pump port, and the two guide fins are arranged oppositely and cross the valve plate; the stability of the fuel pump under low flow conditions is improved.

[0004] If air enters the pump body of an existing fuel pump during operation, the air will occupy the internal space of the pump, causing the pump to be unable to deliver fuel normally, resulting in problems such as insufficient flow and pressure fluctuations. At the same time, during the driving of the vehicle, the oil in the fuel tank may cause bubbles in the oil when it shakes, and such bubbles will be sucked into the pump body along with the oil. When the fuel pump inlet structure in the above patent is in use, it is difficult to effectively break the bubbles that may exist in the oil, and thus it is difficult to eliminate or reduce the gas entering the pump body. Furthermore, during the use of the fuel pump, air binding may occur, resulting in problems such as insufficient fuel flow or pressure fluctuations. Therefore, a fuel pump inlet structure is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a fuel pump inlet structure, which has the advantage of effectively solving the gas binding phenomenon caused by gas accumulation when the fuel pump sucks oil, and solves the problem that the fuel pump may cause insufficient fuel flow or pressure fluctuations due to the gas binding phenomenon during use.

[0006] To achieve the above object, the present invention provides the following technical solutions: a fuel pump inlet structure, comprising an inlet pipe for oil circulation provided on the fuel pump, the middle portion of the inlet pipe comprising an integrally formed bending portion, and a pressure flow exhaust mechanism for eliminating air in the oil in the inlet pipe to prevent air binding problems; The pressure-flow exhaust mechanism comprises an annular base fixedly connected to the inner wall of the inlet pipe, the annular base comprises an integrally formed inner step portion, a conical sealing seat coaxially arranged therewith is provided on the annular base, the conical sealing seat comprises an integrally formed oblique conical surface, and a conical channel for oil liquid to flow is formed between the inner step portion and the oblique conical surface; The annular base is provided with a plurality of groups of micro-diameter holes communicating with the gas between the conical channels, and the annular base is provided with an annular cavity communicating with the gas between the plurality of groups of micro-diameter holes; The inlet pipe is fixedly connected with a special-shaped closed seat which is in communication with the gas between the annular cavity grooves. The special-shaped closed seat is provided with a connecting pipe which is in communication with the gas at the bend part, and the special-shaped closed seat is provided with a self-discharging component which sucks the gas at the bend part.

[0007] Preferably, the cross-sectional area of ​​the tapered channel is smaller than the cross-sectional area of ​​the annular base.

[0008] Preferably, a bubble-blocking net for oil flow is fixedly connected to the inner wall of the bend portion.

[0009] Preferably, a positioning ring is fixedly connected to the annular base, a guide pin is fixedly connected to one end of the conical sealing seat facing the positioning ring, and a circular hole for the guide pin to slide through is opened on the positioning ring; The outer peripheral surface of the guide pin is sleeved with a yield spring, and the two ends of the yield spring are respectively fixedly connected to the positioning ring and the conical sealing seat.

[0010] Preferably, the self-draining component comprises an air-containing chamber opened in a special-shaped closed seat, an air-sealing plate is slidably arranged in the air-containing chamber, and an outer peripheral surface of the air-sealing plate is in sliding contact with an inner wall of the air-containing chamber; The special-shaped sealed seat and the connecting pipe are fixedly connected, and the end of the connecting pipe away from the special-shaped sealed seat is fixedly connected to the bending part, and the connecting pipe and the gas containing chamber are gas-connected.

[0011] Preferably, the inner wall of the special-shaped sealed seat includes an integrally formed extending tooth portion, a retaining ring is fixedly connected to the extending tooth portion, and a metal spring is fixedly connected to the inner circumference of the retaining ring; The air-containing chamber is located below the metal spring, and an oil-sealing chamber filled with oil is provided above the air-containing chamber. A pressure column is fixedly connected to one side of the metal spring facing the air-containing chamber, and the pressure column is fixedly connected to the air sealing plate. A transverse pipeline communicating with the gas between the oil sealing chamber is fixedly passed through the special-shaped sealed seat, and one end of the transverse pipeline away from the special-shaped sealed seat is fixedly passed through the inlet pipeline and communicated with the gas between the annular cavity groove.

[0012] Preferably, a plug is threadedly fixed on the special-shaped closed seat, and limiting columns are fixedly connected to the opposite surfaces of the plug and the metal spring sheet. Reset springs are sleeved on the two groups of limit columns, and the two ends of the reset springs are respectively fixedly connected to the plug and the metal spring sheet.

[0013] Preferably, an air outlet pipe is fixedly passed through the air containing chamber, and a group of one-way valves are fixedly connected to the air outlet pipe and the connecting pipe respectively, and the valve ports of the two groups of one-way valves are in opposite directions.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a pressure-flow exhaust mechanism and utilizes the Venturi effect and the Bernoulli effect to generate low pressure in the tapered channel, so that the gas at the bend is sucked into the special-shaped closed seat through the connecting pipe, thereby preventing the gas from entering the pump body, effectively solving the gas binding phenomenon caused by gas accumulation when the fuel pump sucks oil, ensuring the normal operation of the fuel pump, and avoiding the problems of insufficient fuel flow or pressure fluctuation.

[0015] The present invention is capable of automatically performing exhaust operations according to the low pressure generated by the flow of oil by providing a self-draining component, and automatically resetting when the oil suction stops, thereby exhausting the gas in the air containing chamber and providing reserved space for the subsequent discharge of air in the oil, thereby realizing the automation of exhaust and resetting without manual intervention.

[0016] The present invention provides a bubble-blocking net. When oil flows through the bubble-blocking net, bubbles will collide with the surface of the bubble-blocking net and gather to form larger bubbles. This aggregation effect makes it easier for the bubbles to burst and accumulate together. By aggregating and bursting the bubbles, the bubble-blocking net can significantly improve the discharge efficiency of gas in the oil and reduce the residence time of gas in the oil, thereby effectively preventing the occurrence of gas binding. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the components where the annular base of the present invention is located; Figure 3 For the present invention Figure 2 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the components where the positioning ring of the present invention is located; Figure 5 This is a schematic diagram of the components where the metal spring piece of the present invention is located; Figure 6 For the present invention Figure 5 Enlarged view of point B in the middle; Figure 7 This is a schematic diagram of the initial position of the conical sealing seat of the present invention; Figure 8It is a schematic diagram of the positional relationship between the inner step portion and the inclined cone surface when the oil flows in the present invention.

[0018] In the figure: 1. inlet pipe; 101. bend; 2. bubble-blocking net; 3. annular base; 301. inner step; 4. conical sealing seat; 401. oblique cone; 5. positioning ring; 6. guide pin; 7. yielding spring; 8. micro-diameter hole; 9. annular cavity; 10. special-shaped closed seat; 11. extending tooth portion; 12. retaining ring; 13. metal spring; 14. oil sealing chamber; 15. plug; 16. reset spring; 17. pressure column; 18. air sealing plate; 19. air containing chamber; 20. connecting pipe. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figures 1 to 8 The present invention provides a technical solution: a fuel pump inlet structure, comprising an inlet pipe 1 for oil flow arranged on the fuel pump, the middle part of the inlet pipe 1 comprises an integrally formed bending part 101, and the inlet pipe 1 is provided with a pressure flow exhaust mechanism for eliminating air in the oil in the inlet pipe 1 to prevent air binding problems; The pressure-flow exhaust mechanism comprises an annular base 3 fixedly connected to the inner wall of the inlet pipe 1, the annular base 3 comprises an integrally formed inner step portion 301, a conical sealing seat 4 coaxially arranged therewith is provided on the annular base 3, the conical sealing seat 4 comprises an integrally formed oblique conical surface 401, and a conical channel for oil liquid to flow is formed between the inner step portion 301 and the oblique conical surface 401; The annular base 3 is provided with a plurality of micro-diameter holes 8 for gas communication with the conical channel, and the annular base 3 is provided with an annular cavity 9 for gas communication with the plurality of micro-diameter holes 8; The inlet pipe 1 is fixedly connected with a special-shaped sealed seat 10 which is in gas communication with the annular cavity 9 , the special-shaped sealed seat 10 is provided with a connecting pipe 20 which is in gas communication with the bend 101 , and the special-shaped sealed seat 10 is provided with a self-discharging component for sucking gas at the bend 101 .

[0021] like Figure 1 , Figure 2 , Figure 5 , Figure 7 and Figure 8As shown, when the fuel pump is pumping oil, the oil enters the pump body through the inlet pipe 1, and can push the conical seal 4 to move a certain distance in the annular base 3 through the oil, so as to form a conical channel for oil circulation between the inclined cone surface 401 and the inner step 301.

[0022] At the same time, when the oil flows from the annular base 3 through the tapered channel, the cross-sectional area of ​​the tapered channel is smaller than the cross-sectional area of ​​the annular base 3, and thus under the Venturi effect, the flow rate of the oil increases when passing through the tapered channel, wherein the Venturi effect is expressed as follows: when a fluid (liquid or gas) passes through a pipeline, when the cross-sectional area of ​​the pipeline suddenly becomes smaller, the velocity of the fluid increases and the pressure decreases at the same time; therefore, when the pump body is pumping oil, the flow rate of the oil flowing through the tapered channel increases.

[0023] At the same time, the Bernoulli effect means that in the stable flow of an ideal fluid, along the streamline, the sum of the kinetic energy, potential energy and static pressure energy of a unit volume of fluid remains unchanged, and when the oil flow rate at the tapered channel increases, a low pressure phenomenon will occur at its location. Therefore, the low pressure phenomenon will be transmitted to the annular cavity groove 9 through the multiple groups of micro-diameter holes 8 connected to the tapered channel, and the low pressure will be transmitted to the special-shaped closed seat 10 through the annular cavity groove 9.

[0024] Among them, when there is gas in the oil at the circulation bend 101, the low pressure generated at the special-shaped sealed seat 10 will absorb the gas at the bend 101 through the connecting pipe 20 to promote the gas to enter the special-shaped sealed seat 10, thereby ensuring that the gas is guided out of the bend 101 to eliminate or reduce the amount of gas entering the pump body, thereby avoiding gas binding in the pump body and avoiding problems such as insufficient fuel flow or pressure fluctuations.

[0025] To ensure that bubbles in the oil can gather and arrange, the inner wall of the bend 101 is fixedly connected with a bubble-blocking net 2 for oil circulation. When the oil flows at the bend 101, its flow direction changes and passes through the location of the bubble-blocking net 2. When the oil flows through the bubble-blocking net 2, the bubbles therein will collide with and gather with the surface of the bubble-blocking net 2 to form larger bubbles. When the bubbles are larger, they will burst as the bubble-blocking net 2 expands to release the air wrapped therein.

[0026] At the same time, the connecting position between the connecting pipe 20 and the bend 101 is at the highest level in the bend 101, so that the gas in the bubble after rupture will basically gather at the connecting position between the connecting pipe 20 and the bend 101, and then when the subsequent oil flows through the conical channel position, the channel size can be tightened to prompt the special-shaped closed seat 10 to actively suck the gas gathered at the bend 101 into it, and when the oil suction process is stopped, the gas in the special-shaped closed seat 10 is automatically discharged to ensure that in the subsequent oil suction process, a reserved space is provided for the air in the subsequent oil.

[0027] Furthermore, a positioning ring 5 is fixedly connected to the annular base 3, a guide pin 6 is fixedly connected to one end of the conical sealing seat 4 facing the positioning ring 5, and a circular hole for the guide pin 6 to slide through is opened on the positioning ring 5; The outer circumferential surface of the guide pin 6 is sleeved with a yield spring 7, and the two ends of the yield spring 7 are fixedly connected to the positioning ring 5 and the conical sealing seat 4 respectively.

[0028] like Figure 1 , Figure 2 , Figure 4 , Figure 7 and Figure 8 As shown, when the fuel pump sucks the oil medium, it can pass through the conical sealing seat 4 and the positioning ring 5 in sequence. When sucking the oil, the suction force causes the oil to squeeze the inclined conical surface 401, so as to cause the conical sealing seat 4 and the guide pin 6 thereon to move toward the positioning ring 5, and then the yield spring 7 is compressed and deformed at this time, so that when the oil flows, a conical channel for the oil to flow can be provided through the inner step 301 and the inclined conical surface 401, so as to cause the oil to change the flow cross-sectional size when passing through the annular base 3 and the conical channel position.

[0029] Furthermore, the self-draining assembly includes an air-containing chamber 19 opened in the special-shaped closed seat 10, an air-sealing plate 18 is slidably arranged in the air-containing chamber 19, and the outer peripheral surface of the air-sealing plate 18 is in sliding contact with the inner wall of the air-containing chamber 19; The special-shaped sealed seat 10 and the connecting pipe 20 are fixedly connected, and the end of the connecting pipe 20 away from the special-shaped sealed seat 10 is fixedly connected to the bending portion 101, and the connecting pipe 20 and the gas containing chamber 19 are in gas communication.

[0030] like Figure 1 and Figure 5As shown, when the oil passes through the annular base 3 and the tapered channel position in sequence, due to the smaller cross-sectional size at the tapered channel, the flow rate of the oil at the tapered channel is faster under the Venturi effect, so that under the Bernoulli effect, the negative pressure generated at the tapered channel is transmitted to the special-shaped closed seat 10, and when there is air at the bend 101, it can prompt the air sealing plate 18 to move upward to extract the gas accumulated at the bend 101 through the connecting pipe 20, so that the gas there is sucked into the special-shaped sealed seat 10, and the gas is discharged in time to avoid the gas accumulation in the bend 101 and follow the oil into the pump body, thereby avoiding the occurrence of air binding.

[0031] Based on the embodiment of the self-draining assembly, the inner wall of the special-shaped closed seat 10 includes an integrally formed extending tooth portion 11, a retaining ring 12 is fixedly connected to the extending tooth portion 11, and a metal spring 13 is fixedly connected to the inner circumference of the retaining ring 12; The air containing chamber 19 is located below the metal spring 13, and an oil sealing chamber 14 filled with oil is provided above the air containing chamber 19. A pressure column 17 is fixedly connected to the side of the metal spring 13 facing the air containing chamber 19, and the pressure column 17 is fixedly connected to the air sealing plate 18. A transverse pipe that is in gas communication with the oil sealing chamber 14 is fixedly passed through the special-shaped sealed seat 10, and one end of the transverse pipe away from the special-shaped sealed seat 10 is fixedly passed through the inlet pipe 1 and is in gas communication with the annular cavity 9.

[0032] A plug 15 is threadedly fixed on the special-shaped closed seat 10, and limiting columns are fixedly connected to the opposite surfaces of the plug 15 and the metal spring 13. A return spring 16 is sleeved on the two groups of limit columns, and the two ends of the return spring 16 are fixedly connected to the plug 15 and the metal spring 13 respectively.

[0033] An air outlet pipe is fixedly passed through the air containing chamber 19, and a group of one-way valves are fixedly connected to the air outlet pipe and the connecting pipe 20 respectively, and the valve ports of the two groups of one-way valves are in opposite directions.

[0034] like Figure 1 , Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown, when the oil flows through the conical channel formed by the inner step 301 and the inclined cone surface 401, the negative pressure phenomenon generated at this position is transmitted to the oil sealing chamber 14 through the micro-diameter hole 8, the annular cavity 9 and the transverse pipe. The oil sealing chamber 14 is filled with oil during actual use. Then, when there is accumulated gas at the bend 101, the metal spring 13 can drive the gas sealing plate 18 to move upward synchronously through the pressure column 17 when it is deformed upward, thereby prompting the gas at the bend 101 to enter the air containing chamber 19 through the connecting pipe 20.

[0035] When there is no accumulated gas in the bend 101, the low pressure phenomenon at the transverse pipe is difficult to be transmitted to the oil sealing chamber 14, and the low pressure phenomenon will drive the oil in the oil sealing chamber 14 to have a tendency to move toward the annular cavity 9 and the micro-diameter hole 8, that is, to cause the metal spring 13 to deform upward and cause the pressure column 17 and the gas sealing plate 18 to move upward. However, since the end of the connecting pipe 20 away from the air containing chamber 19 is in contact with the oil in the bend 101, it is difficult to drive the oil in the bend 101 to enter the air containing chamber 19 through the connecting pipe 20. Furthermore, when there is no gas in the bend 101, it is difficult for the oil to compensate for the low pressure phenomenon through the oil in the oil sealing chamber 14 when flowing through the conical channel, and no obvious deformation will occur at this time, thereby not absorbing the oil in the bend 101 into the air containing chamber 19.

[0036] At the same time, when gas accumulates in the bend 101, under the action of the low pressure in the conical channel, part of the oil in the oil sealing chamber 14 enters the transverse pipe, thereby causing the metal spring 13 to deform upward and driving the return spring 16 to compress and deform, thereby driving the pressure column 17 and the gas sealing plate 18 to move upward to suck the gas at the bend 101 through the connecting pipe 20. At the same time, when the pump body stops pumping oil, the conical sealing seat 4 blocks the annular base 3 under the action of the elastic potential energy of the yield spring 7, and drives the metal spring 13 to restore its deformation under the action of the elastic potential energy of the return spring 16, and replenishes the oil in the oil sealing chamber 14 with a small amount of oil in the annular base 3.

[0037] Among them, when the metal spring piece 13 restores its deformation, it prompts the pressure column 17 and the air sealing plate 18 to move downward, so as to prompt the gas in the air chamber 19 to be discharged from the air outlet pipe. It should be noted that by using two sets of one-way valves with opposite valve opening directions fixed on the connecting pipe 20 and the air outlet pipe to limit the flow direction of the gas, the gas accumulated at the bend 101 can enter the air chamber 19 through the connecting pipe 20, and when the metal spring piece 13 is deformed and restored, the gas in the air chamber 19 can be discharged through the outlet pipe, thereby preventing the gas from flowing into the bend 101 through the connecting pipe 20 again.

[0038] It should be noted that, in actual use, the plug 15 and the special-shaped sealed seat 10 are threadedly matched, and before assembling the special-shaped sealed seat 10, the plug 15 can be unscrewed to facilitate the addition of oil to the oil sealing chamber 14 in the special-shaped sealed seat 10. At the same time, the return spring 16 and the plug 15 can be driven to contact and connect with each other, thereby facilitating the assembly of the plug 15. In actual use, the oil sealing chamber 14 is sealed by the plug 15 to avoid leakage of the oil in the oil sealing chamber 14.

[0039] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fuel pump inlet structure, comprising an inlet pipe provided on the fuel pump for oil flow, characterized in that: The middle part of the inlet pipe includes an integrally formed bending part, and the inlet pipe is provided with a pressure flow exhaust mechanism for eliminating air in the oil in the inlet pipe to prevent air binding problems; The pressure-flow exhaust mechanism comprises an annular base fixedly connected to the inner wall of the inlet pipe, the annular base comprises an integrally formed inner step portion, a conical sealing seat coaxially arranged therewith is provided on the annular base, the conical sealing seat comprises an integrally formed oblique conical surface, and a conical channel for oil liquid to flow is formed between the inner step portion and the oblique conical surface; The annular base is provided with a plurality of groups of micro-diameter holes communicating with the gas between the conical channels, and the annular base is provided with an annular cavity communicating with the gas between the plurality of groups of micro-diameter holes; The inlet pipe is fixedly connected with a special-shaped closed seat which is in communication with the gas between the annular cavity grooves. The special-shaped closed seat is provided with a connecting pipe which is in communication with the gas at the bend part, and the special-shaped closed seat is provided with a self-discharging component which sucks the gas at the bend part.

2. A fuel pump inlet structure according to claim 1, characterized in that: The cross-sectional area of ​​the tapered channel is smaller than the cross-sectional area of ​​the annular base.

3. A fuel pump inlet structure according to claim 1, characterized in that: The inner wall of the bending portion is fixedly connected with a bubble-blocking net for oil liquid circulation.

4. A fuel pump inlet structure according to claim 1, characterized in that: A positioning ring is fixedly connected to the annular base, a guide pin is fixedly connected to one end of the conical sealing seat facing the positioning ring, and a circular hole is provided on the positioning ring for the guide pin to slide through; The outer peripheral surface of the guide pin is sleeved with a yield spring, and the two ends of the yield spring are respectively fixedly connected to the positioning ring and the conical sealing seat.

5. A fuel pump inlet structure according to claim 4, characterized in that: The self-draining assembly comprises an air-containing chamber opened in a special-shaped closed seat, an air-sealing plate is slidably arranged in the air-containing chamber, and the outer peripheral surface of the air-sealing plate is in sliding contact with the inner wall of the air-containing chamber; The special-shaped sealed seat and the connecting pipe are fixedly connected, and the end of the connecting pipe away from the special-shaped sealed seat is fixedly connected to the bending part, and the gas between the connecting pipe and the gas containing chamber is in communication with each other.

6. A fuel pump inlet structure according to claim 5, characterized in that: The inner wall of the special-shaped closed seat includes an integrally formed extending tooth portion, a clamping ring is clamped and fixed on the extending tooth portion, and a metal spring is fixedly connected to the inner circumference of the clamping ring; The air-containing chamber is located below the metal spring, and an oil-sealing chamber filled with oil is provided above the air-containing chamber. A pressure column is fixedly connected to one side of the metal spring facing the air-containing chamber, and the pressure column is fixedly connected to the air sealing plate. A transverse pipeline communicating with the gas between the oil sealing chamber is fixedly passed through the special-shaped sealed seat, and one end of the transverse pipeline away from the special-shaped sealed seat is fixedly passed through the inlet pipeline and communicated with the gas between the annular cavity groove.

7. A fuel pump inlet structure according to claim 6, characterized in that: A plug is threadedly fixed on the special-shaped closed seat, and limiting columns are fixedly connected to the opposite surfaces of the plug and the metal spring. Reset springs are sleeved on the two groups of limit columns, and the two ends of the reset springs are respectively fixedly connected to the plug and the metal spring.

8. A fuel pump inlet structure according to claim 5, characterized in that: An air outlet pipe is fixedly passed through the air containing chamber, and a group of one-way valves are fixedly connected to the air outlet pipe and the connecting pipe respectively, and the valve ports of the two groups of one-way valves are in opposite directions.

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