A natural gas engine fuel supply system

Abstract

The present invention relates to the field of engine technology, and discloses a natural gas engine fuel supply system, including an engine body, an intake pipe arranged outside the engine body, a connector arranged in the middle of the intake pipe, a gas interface arranged outside the intake pipe, and a mixing unit arranged in the connector, wherein the intake pipe is divided into an inner pipe and an outer pipe, and the connector is located between the inner pipe and the outer pipe. The natural gas engine fuel supply system, by setting a mixing unit, the natural gas is distributed by the interlayer cavity to flow into each hollow manifold, and then the natural gas is distributed by the upper manifold ports to flow into the embedded tube, flows through the gaps between the hollow manifolds, and carries away the natural gas discharged from the upper manifold ports, so that the natural gas is evenly divided into multiple portions, so that the contact area between the natural gas and the air becomes larger, so that the two can be evenly mixed in a short time, and the situation of incomplete combustion of the mixed gas is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to a fuel supply system for a natural gas engine. Background Art

[0002] A natural gas engine is an internal combustion engine that uses natural gas as fuel. The working principle of a natural gas engine is similar to that of a traditional gasoline engine and a diesel engine. It completes a working cycle through four strokes: intake, compression, power generation, and exhaust. It uses natural gas as energy and has the advantages of energy saving, environmental protection, safety, and reliability. Therefore, natural gas engines are also used in many fields, such as taxis and buses, and can also be used for power generation.

[0003] When the air intake device of the natural gas engine is working, the purified air is pumped into the engine cylinder through the intake pipe. In the process of air flowing into the engine cylinder, natural gas is injected into the intake pipe in a certain proportion, so that the natural gas is mixed with the air to obtain a mixed gas. Finally, the mixed gas enters the engine cylinder and is ignited to do work. The mixing ratio of natural gas and air is roughly 1:20-50.

[0004] The prior art has the following defects:

[0005] When natural gas and air are mixed, natural gas is directly injected into the air. Due to the large difference in the ratio between the two gases, the limited internal space of the intake pipe, and the short transportation distance, the mixing effect of the two gases is poor. Such a mixed gas may not burn fully, the power generated is small, and it will cause more carbon deposits and increase the emission of harmful gases, which will have a serious impact on the engine and users.

[0006] When natural gas is slowly released from the gas tank, it transfers from a high-pressure environment to a low-pressure environment and its temperature drops. When the air meets the air with lower temperature, the water vapor inside it will condense into water droplets. If these water droplets accumulate inside the intake pipe for a long time, it will affect the mixing and circulation of the two gases and cause abnormal noises. If the water droplets enter the engine with the airflow, they may damage the engine. Summary of the invention

[0007] In view of the problem that the natural gas and air are not mixed evenly in the prior art and water may accumulate during mixing, a natural gas engine fuel supply system is proposed.

[0008] The present application provides a natural gas engine fuel supply system, the purpose of which is to evenly mix natural gas and air and clean up accumulated water.

[0009] The technical solution of the present invention is: a natural gas engine fuel supply system, including an engine body, an intake pipe arranged on the outside of the engine body, a connecting piece arranged in the middle of the intake pipe, a gas interface arranged on the outside of the intake pipe, and also including a mixing unit arranged in the connecting piece, the intake pipe is divided into an inner pipe and an outer pipe, the connecting piece is located between the inner pipe and the outer pipe, the mixing unit specifically includes an embedded pipe arranged inside the connecting piece, a sandwich cavity opened inside the wall of the embedded pipe, a flow opening opened outside the embedded pipe, a hollow manifold arranged inside the embedded pipe, an upper manifold opening opened on the surface of the hollow manifold, a lower manifold opening and a connecting hole opened on the inner wall of the embedded pipe, and a docking hole opened on the outer edge of the hollow manifold;

[0010] The interlayer cavity is annular, and the flow port connects the gas interface and the interlayer cavity. The hollow diverter plate is distributed in a linear array in the vertical direction inside the embedded tube, and the upper diverter port is distributed in a rectangular array on the surface of the hollow diverter plate. The lower diverter port is located below the hollow diverter plate. The lower diverter port and the connecting hole are both connected to the interlayer cavity. The opening position of the connecting hole corresponds one-to-one to the docking hole, and the two cooperate to connect the hollow diverter plate and the interlayer cavity.

[0011] Furthermore, the outer sides of the inner and outer tubes are fixedly connected with merging plates, the inner and outer tubes are threadedly connected to the interior of the connector, and the merging plates on the outer sides of the inner and outer tubes are respectively fitted with both ends of the connector.

[0012] Further, the inner diameter of the embedded tube is the same as the inner diameters of the inner tube and the outer tube.

[0013] Furthermore, the connecting member includes an outer sleeve arranged between the inner pipe and the outer pipe, a positioning sliding groove provided inside the outer sleeve, a positioning sliding block arranged outside the embedded pipe, and a plugging joint arranged at one end of the outer sleeve close to the outer pipe;

[0014] The internal space of the outer sleeve is divided into two sections, front and back sections. The front section is close to the external tube and has a relatively small inner diameter, while the rear section is close to the external tube and has a relatively large inner diameter. The positioning sliding groove extends to one end of the outer sleeve for installing the sealing joint. The embedded tube is slidably installed in the rear section space in the outer sleeve through the cooperation of the positioning slider and the positioning sliding groove. The sealing joint extends into the outer sleeve and presses on one end of the embedded tube.

[0015] Furthermore, the mixing unit further comprises an assembly slide groove opened inside the embedded tube, and a fixing cap arranged at one end of the embedded tube close to the internal tube;

[0016] The assembly slide groove is symmetrically arranged inside the embedded tube, the connecting hole is located in the assembly slide groove, the assembly slide groove extends to one end of the embedded tube for installing a fixing cap, the hollow diverter plate is slidably installed in the assembly slide groove, and the fixing cap is annular.

[0017] Furthermore, the mixing unit further comprises a reinforcing threaded hole penetrating through the surface of the fixing cap, and a reinforcing threaded bolt arranged inside the reinforcing threaded hole;

[0018] The positions of the reinforcing threaded holes correspond one-to-one to the assembly sliding grooves, and the reinforcing threaded bolts are pressed against the outer sides of the docking holes.

[0019] Furthermore, the hollow diverter plate is divided into a main frame and a cover plate, the surface of the main frame is provided with an opening, the cover plate is clamped in the opening, the upper diverter port is located on the surface of the cover plate, and a metal filter is installed in the upper diverter port.

[0020] Furthermore, a water filter unit is provided in the connecting piece, and the water filter unit specifically includes an outer flow groove provided at the lowest point of the inner wall of the outer sleeve, a drainage groove provided at one end of the embedded pipe close to the plugging joint, a drainage hole provided on the outer side of the outer sleeve, and a closing bolt provided inside the drainage hole;

[0021] The outer flow groove is located directly below the central axis of the outer sleeve, and the drainage groove is located above the outer flow groove, and the two are interconnected. The drainage hole passes through the outer flow groove to the interlayer cavity, and the closing bolt completely passes through the drainage hole and is threadedly connected thereto.

[0022] Furthermore, the bottom of the inner wall of the embedded tube and the hollow diverter plate are both designed to be inclined, wherein the side close to the inner tube is higher and the side close to the outer tube is lower.

[0023] Beneficial effects of the present invention:

[0024] 1. By setting up a mixing unit, natural gas is distributed by the interlayer cavity and flows into each hollow manifold plate, and then the natural gas is distributed by each upper manifold port and flows into the embedded tube. The air flows through the embedded tube and flows through the gaps between the hollow manifold plates, entraining the natural gas discharged from the upper manifold port. In this way, the natural gas is evenly divided into multiple parts, so that the contact area between the natural gas and the air becomes larger, so that the two can be evenly mixed in a short time, avoiding the situation of incomplete combustion of the mixed gas.

[0025] 2. Through the design of the connector and the mixing unit, it is convenient to remove the mixing unit from the outer sleeve, and it is also convenient to remove the hollow diverter plate from the embedded tube. This simplifies the assembly mode of the equipment, making it easier to disassemble and assemble, and the cleaning, maintenance and repair after use become simple, and the use cost is reduced.

[0026] 3. By setting a reinforcing threaded bolt corresponding to the hollow manifold, when the hollow manifold is deformed due to long-term airflow scouring and the connection becomes loose, the hollow manifold can be pressed by the reinforcing threaded bolt to avoid abnormal airflow or abnormal noise caused by collision of parts due to loose hollow manifold.

[0027] 4. By setting a filter in the upper diversion port, the filter can divide the natural gas flowing out of the upper diversion port into countless small gas columns, so that it can be mixed with the air more fully. At the same time, the filter can also filter impurities in the natural gas to prevent these impurities from entering the engine and avoiding engine damage. The detachable cover facilitates the cleaning of the inside of the hollow diversion plate and the upper diversion port.

[0028] 5. By setting up a water filter unit, air enters the embedded tube, and the water vapor inside it condenses on the surface of the hollow diverter plate. Water droplets slide down the slope and enter the external flow groove through the drainage groove for storage. Some water droplets may enter the hollow diverter plate. These water droplets will gather at the bottom of the interlayer cavity. After a period of time, the closed bolts can be turned out to discharge the accumulated water. This can quickly clean up the accumulated water and prevent the accumulated water from entering the engine body. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A perspective view of a natural gas engine fuel supply system according to the present invention;

[0030] Figure 2 A top view of the air intake pipe and the connecting piece of the present invention;

[0031] Figure 3 It is a schematic diagram of the air intake pipe and the connecting piece of the present invention;

[0032] Figure 4 This is a disassembled diagram of the air intake pipe and the connecting parts of the present invention;

[0033] Figure 5 This is a disassembly diagram of the connector of the present invention;

[0034] Figure 6 This is a disassembled diagram of the mixing unit of the present invention;

[0035] Figure 7 This is a schematic diagram of the interior of the embedded tube of the present invention;

[0036] Figure 8 It is a schematic diagram of the hollow diverter plate and the fixing cap of the present invention;

[0037] Fig. 9 It is a schematic diagram of the fixing cap of the present invention;

[0038] Fig.10 For the present invention Figure 2 Sectional view at AA;

[0039] Fig.11 For the present invention Fig.10 A magnified image of the selected area;

[0040] Fig.12 It is a schematic diagram of the water filtration unit of the present invention.

[0041] In the figure:

[0042] 1. Engine body; 2. Intake pipe; 21. Internal pipe; 22. External pipe; 23. Merging plate; 3. Connectors; 31. Outer sleeve; 32. Sealing joint; 33. Positioning slide groove; 34. Positioning slide block; 4. Gas interface; 5. Mixing unit; 51. Embedded pipe; 52. Interlayer cavity; 53. Flow port; 54. Hollow diverter plate; 541. Main frame; 542. Cover plate; 55. Upper diverter port; 56. Lower diverter port; 57. Connecting hole; 58. Docking hole; 59. Assembly slide groove; 510. Fixing cap; 511. Reinforcement threaded hole; 512. Reinforcement threaded bolt; 6. Water filter unit; 61. External flow groove; 62. Drainage groove; 63. Drain hole; 64. Closing bolt. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0044] Example 1, reference Figure 1-Figure 10 , which is the first embodiment of the present invention, provides a natural gas engine fuel supply system, including an engine body 1, an intake pipe 2 arranged on the outside of the engine body 1, a connecting piece 3 arranged in the middle of the intake pipe 2, a gas interface 4 arranged on the outside of the intake pipe 2, and also includes a mixing unit 5 arranged in the connecting piece 3, the intake pipe 2 is divided into an inner pipe 21 and an outer pipe 22, the connecting piece 3 is located between the inner pipe 21 and the outer pipe 22, the mixing unit 5 specifically includes an embedded pipe 51 arranged inside the connecting piece 3, an interlayer cavity 52 opened inside the pipe wall of the embedded pipe 51, a flow port 53 opened outside the embedded pipe 51, a hollow diverter plate 54 arranged inside the embedded pipe 51, an upper diverter port 55 opened on the surface of the hollow diverter plate 54, a lower diverter port 56 and a connecting hole 57 opened on the inner wall of the embedded pipe 51, and a docking hole 58 opened on the outer edge of the hollow diverter plate 54.

[0045] Specifically, the inner pipe 21 is welded to the engine body 1, the outer pipe 22 is connected to the purifier, the gas interface 4 is connected to the gas tank through a pipeline, the interlayer cavity 52 is annular, the flow port 53 connects the gas interface 4 and the interlayer cavity 52, the hollow diverter plate 54 is distributed in a linear array in the vertical direction in the embedded tube 51, the upper diverter port 55 is distributed in a rectangular array on the surface of the hollow diverter plate 54, the lower diverter port 56 is located below the hollow diverter plate 54, the lower diverter port 56 and the connecting hole 57 are both connected to the interlayer cavity 52, the opening position of the connecting hole 57 corresponds one by one to the docking hole 58, and the two cooperate to connect the hollow diverter plate 54 and the interlayer cavity 52, and a plurality of docking holes 58 are arranged on a hollow diverter plate 54.

[0046] By setting up the mixing unit 5, the natural gas is distributed by the interlayer cavity 52 to flow into each hollow diverter plate 54, and then the natural gas is distributed by each upper diverter port 55 to flow into the embedded tube 51. The air flows through the embedded tube 51 and flows through the gaps between the hollow diverter plates 54, entraining the natural gas discharged from the upper diverter port 55. In this way, the natural gas is evenly divided into multiple portions, so that the contact area between the natural gas and the air becomes larger, so that the two can be evenly mixed in a short time, avoiding the situation of incomplete combustion of the mixed gas.

[0047] Specifically, the outer sides of the internal pipe 21 and the external pipe 22 are fixedly connected with a merging plate 23, and the internal pipe 21 and the external pipe 22 are threadedly connected to the interior of the connecting piece 3, and the merging plates 23 on the outer sides of the internal pipe 21 and the external pipe 22 are respectively fitted with the two ends of the connecting piece 3, and the fitting parts are fixed with bolts. The length of the internal pipe 21 and the external pipe 22 inserted into the connecting piece 3 is not less than five centimeters. By adopting such a connection method, the internal pipe 21, the external pipe 22 and the connecting piece 3 are partially overlapped, and then with the merging plate 23, the connection between the internal pipe 21, the external pipe 22 and the connecting piece 3 is made tighter, avoiding leakage here, making the equipment safer to use; the inner diameter of the embedded pipe 51 is the same as the inner diameter of the internal pipe 21 and the external pipe 22, so that the internal air flow can flow more smoothly.

[0048] The connecting member 3 includes an outer sleeve 31 arranged between the internal pipe 21 and the external pipe 22, a positioning sliding groove 33 opened inside the outer sleeve 31, a positioning slider 34 arranged on the outside of the embedded pipe 51, and a sealing joint 32 arranged at one end of the outer sleeve 31 close to the external pipe 22; the mixing unit 5 also includes an assembly sliding groove 59 opened inside the embedded pipe 51, and a fixing cap 510 arranged at one end of the embedded pipe 51 close to the internal pipe 21.

[0049] Specifically, the internal space of the outer sleeve 31 is divided into two sections, the front section is close to the external pipe 22, and the inner diameter is relatively small, and the rear section is close to the external pipe 22, and the inner diameter is relatively large, which can limit the embedded pipe 51. The positioning sliding groove 33 extends to one end of the outer sleeve 31 where the plugging joint 32 is installed. The embedded pipe 51 is slidably installed in the rear section space of the outer sleeve 31 through the cooperation of the positioning slider 34 and the positioning sliding groove 33, ensuring that the installation angle of the embedded pipe 51 will not deviate. The plugging joint 32 extends into the outer sleeve 31 and presses on one end of the embedded pipe 51. The other end of the embedded pipe 51 presses on the junction of the front and rear sections of the outer sleeve 31. The plugging joint 32 is fixed to the outer sleeve 31 by bolts, and the plugging joint 32 is connected to the external pipe 22 by bolts. The outer sleeve 31 is connected to the internal pipe 21 by bolts.

[0050] The assembly groove 59 is symmetrically arranged inside the embedded tube 51, and the connecting hole 57 is located in the assembly groove 59. The assembly groove 59 extends to one end of the embedded tube 51 where the fixing cap 510 is installed. The hollow diverter plate 54 is slidably installed in the assembly groove 59. The fixing cap 510 is annular and is threadedly connected to the embedded tube 51. The inner wall of the reinforced threaded hole 511 is pressed against the outer side of the embedded tube 51 to completely block the assembly groove 59. The hollow diverter plate 54 is confined in the assembly groove 59.

[0051] Through the design of the connecting piece 3 and the mixing unit 5, it is convenient to remove the mixing unit 5 from the outer sleeve 31, and it is also convenient to remove the hollow diverter plate 54 from the embedded tube 51. This simplifies the assembly mode of the equipment, making it easier to disassemble and assemble, and the cleaning, maintenance and repair after use become simple, and the cost of use is reduced.

[0052] The mixing unit 5 further includes a reinforcing threaded hole 511 penetrating through the surface of the fixing cap 510 , and a reinforcing threaded bolt 512 disposed inside the reinforcing threaded hole 511 .

[0053] Specifically, the position of the reinforcement threaded hole 511 corresponds one-to-one to the assembly slot 59, the reinforcement threaded bolt 512 presses against the outside of the docking hole 58, and positioning lines are engraved on the surfaces of the fixing cap 510 and the embedded tube 51 to ensure the accuracy of the positioning of the reinforcement threaded hole 511 and the assembly slot 59.

[0054] By providing a reinforcing threaded bolt 512 corresponding to the hollow diverter plate 54, when the hollow diverter plate 54 is deformed due to long-term airflow scouring and the connection becomes loose, the reinforcing threaded bolt 512 is used to tighten the hollow diverter plate 54 to avoid abnormal airflow or abnormal noise caused by collision of parts due to the looseness of the hollow diverter plate 54.

[0055] Specifically, the hollow diverter plate 54 is divided into a main frame 541 and a cover plate 542. An opening is provided on the surface of the main frame 541, and the cover plate 542 is clamped in the opening, and the two are fixed with screws. The upper diverter port 55 is located on the surface of the cover plate 542, and metal filters are installed in the upper diverter port 55 and the lower diverter port 56.

[0056] By arranging a filter in the upper diversion port 55, the filter can divide the natural gas flowing out of the upper diversion port 55 into countless small gas columns, so that it can be mixed with the air more fully. At the same time, the filter can also filter impurities in the natural gas to prevent these impurities from entering the engine and avoiding damage to the engine. The detachable cover plate 542 facilitates the cleaning of the interior of the hollow diversion plate 54 and the upper diversion port 55.

[0057] Example 2, reference Figure 5-Figure 7 , Figure 10-12, which is the second embodiment of the present invention. This embodiment is different from the first embodiment in that a water filter unit 6 is arranged in the connecting member 3, and the water filter unit 6 specifically includes an outer flow groove 61 opened at the lowest point of the inner wall of the outer sleeve 31, a drainage groove 62 opened at one end of the embedded tube 51 close to the sealing joint 32, a drainage hole 63 opened on the outside of the outer sleeve 31, and a closing bolt 64 arranged inside the drainage hole 63.

[0058] Specifically, a guiding slope is provided at one end of the embedded tube 51 close to the sealing joint 32, the outer flow groove 61 is located directly below the central axis of the outer sleeve 31, the drainage groove 62 is located above the outer flow groove 61, and the two are connected to each other, the drainage hole 63 passes through the outer flow groove 61 to penetrate into the interlayer cavity 52, the closing bolt 64 completely penetrates the drainage hole 63 and is threadedly connected thereto; the bottom of the inner wall of the embedded tube 51 and the hollow diverter plate 54 are both designed to be inclined, wherein the side close to the inner pipe 21 is higher and the side close to the external pipe 22 is lower.

[0059] By setting up the water filtering unit 6, air enters the embedded tube 51, and the water vapor inside it condenses on the surface of the hollow diverter plate 54. Water droplets slide down the slope and enter the outer flow groove 61 through the drainage groove 62 for storage. Some water droplets may enter the hollow diverter plate 54, and these water droplets will gather at the bottom of the interlayer cavity 52. ​​After a period of time, the closing bolt 64 is turned and removed to discharge the accumulated water. In this way, the accumulated water can be quickly cleaned up and the accumulated water can be prevented from entering the engine body 1.

[0060] Based on Examples 1-2, the working principle of a natural gas engine fuel supply system of the present invention is as follows:

[0061] When assembling the equipment: weld the metal filter into the upper diversion port 55, then buckle the cover plate 542 at the opening of the main frame 541 and fix it with screws, then insert the hollow diversion plates 54 into the embedded tube 51 through the assembly slot 59 according to their sizes, so that the docking hole 58 and the connecting hole 57 are docked, and then install the fixing cap 510 on one end of the embedded tube 51 through threads, close the assembly slot 59, and confine the hollow diversion plate 54 therein, and finally screw the reinforcing threaded bolts 512 into the reinforcing threaded holes 511 one by one, so that the reinforcing threaded bolts 512 are pressed against the surface of the hollow diversion plate 54, thus completing the assembly of the mixing unit 5.

[0062] With the flow port 53 facing upwards, align the positioning slider 34 and the positioning sliding groove 33, insert the mixing unit 5 from the side with the larger opening of the outer sleeve 31. After it is fully inserted, the flow port 53 and the gas interface 4 are connected, and the drainage groove 62 and the external flow groove 61 are connected. Then, the sealing joint 32 is connected to one end of the outer sleeve 31 and fixed with bolts. In this way, the assembly of the connecting piece 3 is completed. Finally, the connecting piece 3 is fixed between the inner pipe 21 and the outer pipe 22 with bolts.

[0063] When the device is started, air flows to the engine body 1 through the external pipe 22 , passing through the connector 3 and the internal pipe 21 , and natural gas is input into the connector 3 through the gas interface 4 .

[0064] Natural gas enters the interlayer cavity 52 from the flow port 53, fills the interlayer cavity 52, and then flows into each hollow manifold plate 54 from multiple connecting holes 57 and docking holes 58, fills the hollow manifold plates 54, and then flows out from multiple upper manifold ports 55, filling the gaps between the hollow manifold plates 54. When air flows through the connector 3, it first enters the embedded tube 51, and then flows through the gaps between the hollow manifold plates 54, entraining the natural gas filled therein, and then the mixed gas enters the internal pipe 21, and finally flows into the engine body 1, and is ignited to do work.

[0065] When the air mixes with the hot weather in the embedded tube 51, the air encounters the natural gas with a lower temperature, the inner wall of the embedded tube 51, and the outer wall of the hollow diverter plate 54 (the natural gas continuously flows in the sandwich cavity 52 and the hollow diverter plate 54, causing the temperatures of both to decrease accordingly). The water vapor in the air condenses into water droplets at the metal filter in the hollow diverter plate 54, the inner wall of the embedded tube 51, and the surface of the hollow diverter plate 54. The air can easily flow upward along the inclined hollow diverter plate 54 and enter the inner tube 21. The water droplets on the metal filter screen in the hollow diverter plate 54 will drip into the inside of the hollow diverter plate 54 under the action of weight, and then flow downward along the slope inside the hollow diverter plate 54, and then flow into the interlayer cavity 52 through the docking hole 58 and the connecting hole 57, and finally gather at the lowest point of the interlayer cavity 52, while the water droplets on the inner wall of the embedded tube 51 and the surface of the hollow diverter plate 54 will flow downward along the slope, gather on one side of the embedded tube 51, and then flow into the outer flow groove 61 through the drainage groove 62.

[0066] During maintenance or when an abnormality occurs during use, use a tool to remove the closing bolt 64 from the drain hole 63, and the accumulated water in the interlayer cavity 52 and the outer flow groove 61 will be discharged through the drain hole 63. If the problem is still not solved, it can be disassembled again to check for damage and clean it. After that, after assembling the mixing unit 5, shake it at multiple angles to determine whether the hollow diverter plate 54 is loose. If there is an abnormal sound, turn the reinforcing threaded bolt 512 to further tighten the hollow diverter plate 54.

[0067] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A natural gas engine fuel supply system, comprising an engine body (1), an intake pipe (2) arranged outside the engine body (1), a connecting piece (3) arranged in the middle of the intake pipe (2), and a gas interface (4) arranged outside the intake pipe (2), characterized in that: It also includes a mixing unit (5) arranged in the connecting piece (3), the air intake pipe (2) is divided into two parts, an inner pipe (21) and an outer pipe (22), the connecting piece (3) is located between the inner pipe (21) and the outer pipe (22), the mixing unit (5) specifically includes an embedded pipe (51) arranged in the connecting piece (3), a sandwich cavity (52) opened in the pipe wall of the embedded pipe (51), a flow opening (53) opened on the outer side of the embedded pipe (51), a hollow flow dividing plate (54) arranged in the inner side of the embedded pipe (51), an upper flow dividing opening (55) opened on the surface of the hollow flow dividing plate (54), a lower flow dividing opening (56) and a connecting hole (57) opened on the inner wall of the embedded pipe (51), and a docking hole (58) opened on the outer edge of the hollow flow dividing plate (54); The interlayer cavity (52) is annular, the flow port (53) is connected to the gas interface (4) and the interlayer cavity (52), the hollow diverter plate (54) is arranged in a linear array in the vertical direction inside the embedded tube (51), the upper diverter port (55) is arranged in a rectangular array on the surface of the hollow diverter plate (54), the lower diverter port (56) is located below the hollow diverter plate (54), the lower diverter port (56) and the connecting hole (57) are both connected to the interlayer cavity (52), the opening position of the connecting hole (57) corresponds to the docking hole (58), and the two cooperate to connect the hollow diverter plate (54) and the interlayer cavity (52); The connecting member (3) comprises an outer sleeve (31) arranged between the inner pipe (21) and the outer pipe (22), a positioning sliding groove (33) provided inside the outer sleeve (31), a positioning sliding block (34) arranged outside the embedded pipe (51), and a blocking joint (32) arranged at one end of the outer sleeve (31) close to the outer pipe (22); The internal space of the outer sleeve (31) is divided into two sections, front and rear sections. The front section is close to the external tube (22) and has a relatively small inner diameter, while the rear section is close to the external tube (22) and has a relatively large inner diameter. The positioning sliding groove (33) extends to one end of the outer sleeve (31) where the plugging joint (32) is installed. The embedded tube (51) is slidably installed in the rear section space of the outer sleeve (31) through the cooperation of the positioning slider (34) and the positioning sliding groove (33). The plugging joint (32) extends into the outer sleeve (31) and presses against one end of the embedded tube (51). The mixing unit (5) further comprises an assembly slide groove (59) disposed inside the embedded tube (51), and a fixing cap (510) disposed at one end of the embedded tube (51) close to the internal tube (21); The assembly slide groove (59) is symmetrically arranged inside the embedded tube (51), the connection hole (57) is located in the assembly slide groove (59), the assembly slide groove (59) extends to one end of the embedded tube (51) where the fixing cap (510) is installed, the hollow diverter plate (54) is slidably installed in the assembly slide groove (59), and the fixing cap (510) is annular; The mixing unit (5) further comprises a reinforcing threaded hole (511) penetrating through the surface of the fixing cap (510), and a reinforcing threaded bolt (512) disposed inside the reinforcing threaded hole (511); The positions of the reinforcing threaded holes (511) correspond one-to-one to the assembly sliding grooves (59), and the reinforcing threaded bolts (512) are pressed against the outer sides of the docking holes (58).

2. The natural gas engine fuel supply system according to claim 1, characterized in that: The outer sides of the inner tube (21) and the outer tube (22) are both fixedly connected with a merging plate (23); the inner tube (21) and the outer tube (22) are both threadedly connected to the interior of the connecting piece (3); and the merging plates (23) on the outer sides of the inner tube (21) and the outer tube (22) are respectively fitted with two ends of the connecting piece (3).

3. The natural gas engine fuel supply system according to claim 2, characterized in that: The inner diameter of the embedded tube (51) is the same as the inner diameters of the inner tube (21) and the outer tube (22).

4. The natural gas engine fuel supply system according to claim 3, characterized in that: The hollow flow dividing plate (54) is divided into a main frame (541) and a cover plate (542); an opening is provided on the surface of the main frame (541); the cover plate (542) is clamped in the opening; the upper flow dividing port (55) is located on the surface of the cover plate (542); and a metal filter is installed in the upper flow dividing port (55).

5. The natural gas engine fuel supply system according to claim 4, characterized in that: The connecting member (3) is provided with a water filtering unit (6), which specifically comprises an outer flow groove (61) provided at the lowest point of the inner wall of the outer sleeve (31), a drainage groove (62) provided at one end of the embedded tube (51) close to the plugging joint (32), a drainage hole (63) provided on the outer side of the outer sleeve (31), and a closing bolt (64) provided inside the drainage hole (63); The outer flow groove (61) is located directly below the central axis of the outer sleeve (31), and the drainage groove (62) is located above the outer flow groove (61), and the two are interconnected. The drainage hole (63) passes through the outer flow groove (61) to the interlayer cavity (52), and the closing bolt (64) completely passes through the drainage hole (63) and is threadedly connected thereto.

6. The natural gas engine fuel supply system according to claim 5, characterized in that: The bottom of the inner wall of the embedded tube (51) and the hollow flow divider plate (54) are both designed to be inclined, with the side close to the inner tube (21) being higher and the side close to the outer tube (22) being lower.

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