A low noise fuel injector assembly for an internal combustion engine and method of use

Abstract

The application relates to the technical field of fuel injection nozzles of internal combustion engines, in particular to a low-noise fuel injection nozzle assembly of an internal combustion engine and a use method, which comprises an upper shell, a lower shell is fixedly installed at the lower end of the upper shell, a coil outer shell is fixedly installed at the upper end of the upper shell, a valve seat is fixedly installed at the lower end of the lower shell, and a needle valve is movably installed in the valve seat. The hydraulic buffer groove and the pre-injection oil groove are arranged in the lower shell. The lower oil pipe injects oil in the hydraulic buffer groove through a pre-oil outlet to form a buffer layer. When the armature is lifted to the upper baffle ring by the electromagnetic coil assembly, the extrusion plate extrudes the oil in the hydraulic buffer groove through the pre-conveying pipe, the pre-injection oil groove and the pre-injection oil pipe to form pre-injection, gently lifts the in-cylinder pressure before main injection, greatly reduces the knocking sound caused by the violent combustion of fuel during main injection, and the buffer layer formed in the hydraulic buffer groove can reduce the impact during the movement of the needle valve.

Description

Technical Field

[0001] This invention belongs to the field of internal combustion engine fuel injector technology, specifically relating to a low-noise internal combustion engine fuel injector assembly and its usage method. Background Technology

[0002] The fuel injector assembly is like a precision "injector" in an internal combustion engine's fuel system. Its core function is to atomize and inject a precise amount of fuel at a precise time. A typical electromagnetic fuel injector assembly mainly consists of the following components: an electromagnetic coil and an armature. When a fuel injection signal is received, the coil is energized, generating electromagnetic force that attracts the armature, thereby driving the valve needle; the needle valve stem and needle valve seat are a precision pair with extremely small clearance. The valve stem head engages with the valve seat, responsible for opening and closing the fuel injection orifice. After the electromagnetic force disappears, the return spring uses its elasticity to press the valve stem back to the valve seat, closing the fuel injection orifice and stopping fuel injection. Fuel injectors generate noise during operation, essentially due to high-frequency mechanical impacts and fuel pressure fluctuations. Existing fuel injectors have poor noise reduction capabilities, potentially resulting in significant noise during use. Therefore, a low-noise fuel injector is needed.

[0003] A Chinese patent document with publication number CN214836817U proposes a low-noise fuel injector. It solves the above-mentioned technical problem by using the fuel injector body, mounting base, noise reduction box, heat sink, first sound-absorbing cotton, fixing nut, fixing bolt, heat dissipation hole, second sound-absorbing cotton and dustproof net in combination to improve the noise reduction performance of the fuel injector body. However, the above method adds a heavy noise reduction box and heat sink, which will significantly increase the radial and axial dimensions of the fuel injector assembly. This makes it impossible for the fuel injector to be installed into the original mounting hole, or it will cause mechanical interference with surrounding components such as camshaft, valve cover, and high-pressure fuel rail after installation.

[0004] Therefore, this invention proposes a low-noise internal combustion engine fuel injector assembly and its usage method, solving the problem that adding a heavy noise reduction box and heat sink in the prior art would significantly increase the radial and axial dimensions of the fuel injector assembly. By improving the structure of the injector itself, a two-layer fuel injection component is designed inside the injector, allowing a complete lifting action to be naturally divided into two sequential injections, forming a throttling effect. At the moment the injector just opens, only the upper injection orifice is opened first, pre-injecting a small amount of fuel, and gradually increasing the cylinder pressure before the main injection. This significantly reduces the knocking sound caused by the violent combustion of fuel during the main injection, and also reduces the impact of valve needle movement, thus achieving the goal of low noise. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a low-noise internal combustion engine fuel injector assembly and its usage method, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a low-noise internal combustion engine fuel injector assembly, comprising an upper housing, a lower housing fixedly mounted at the lower end of the upper housing, a coil housing fixedly mounted at the upper end of the upper housing, a valve seat fixedly mounted at the lower end of the lower housing, a needle valve movably mounted inside the valve seat, a sliding groove adapted to the needle valve being provided in the middle of both the lower housing and the upper housing, an oil inlet chamber fixedly mounted at the upper end of the coil housing, and an oil inlet pipe fixedly mounted on one side of the oil inlet chamber.

[0007] Preferably, a closed cover is fixedly installed on the top of the oil inlet, an upper filter tank is provided inside the upper part of the oil inlet, and an oil storage tank is provided inside the lower part of the oil inlet.

[0008] Preferably, a flow guide is fixedly installed below the closed cover, and a filter cover is fixedly installed at the lower end of the flow guide. The flow guide and the filter cover are snapped together and installed below the upper filter tank. Discharge ports are evenly opened on the lower side wall of the flow guide, and an impurity storage ring is provided on the outer side of the filter cover.

[0009] Preferably, an upper oil pipe is symmetrically fixedly installed on the inner wall of the upper housing, the top end of the upper oil pipe penetrating the bottom inner wall of the oil storage tank; a lower oil pipe is symmetrically fixedly installed on the inner wall of the lower housing; a pre-outlet is provided on the side wall of the lower oil pipe, the pre-outlet is located inside the hydraulic buffer tank; the upper end of the lower oil pipe is snapped into the lower end of the upper oil pipe; the lower oil pipe penetrates the inner walls of both sides of the valve seat; an oil control groove is provided in the middle of the valve seat; connecting pipes are symmetrically fixedly installed on both sides of the oil control groove; the upper end of the connecting pipe is fixedly connected to the lower end of the lower oil pipe.

[0010] Preferably, an electromagnetic coil assembly is fixedly installed inside the coil housing, an armature movable slot is provided on the upper part of the upper housing, an armature is slidably installed inside the armature movable slot, the armature is slidably installed outside the needle valve, an upper retaining ring is fixedly installed on the top of the needle valve, a return spring is sleeved on the middle part of the needle valve, and the upper end of the return spring is fixedly connected to the lower middle part of the lower housing.

[0011] Preferably, a hydraulic buffer groove is provided inside the upper part of the lower housing, a pre-feeding pipe is fixedly installed inside the hydraulic buffer groove, an oil discharge hole is provided at the top of the pre-feeding pipe, an extrusion plate is provided inside the lower housing, a support spring is fixedly installed at the lower end of the extrusion plate, the extrusion plate is slidably installed below the armature through the support spring, and a guide groove is provided on the upper surface of the extrusion plate.

[0012] Preferably, a pre-spraying oil groove is provided inside the lower housing, the lower end of the pre-delivery pipe passes through the top of the pre-spraying oil groove, a nozzle is provided inside the lower valve seat, a spray hole is opened at the bottom of the nozzle, and the lower end of the needle valve contacts the upper part of the spray hole.

[0013] Preferably, an outer sleeve is fixedly installed on the lower outer side of the valve seat, and a pre-injection pipe is symmetrically fixedly installed in the middle of the outer sleeve, with the upper end of the pre-injection pipe penetrating the bottom of the pre-injection groove.

[0014] Preferably, a pre-nozzle is provided at the lower end of the pre-injection pipe, and the pre-nozzle is located obliquely below the injection hole.

[0015] The present invention also proposes a method of using a low-noise internal combustion engine fuel injector assembly, comprising the following steps: Step 1, fuel enters the fuel inlet chamber for filtration through the fuel inlet pipe, is guided by the flow guide and discharged through the outlet to the top of the filter cover, and the filtered pure fuel is temporarily stored inside the fuel storage tank. Step 2, pre-injection: The lower oil pipe stores a small amount of fuel in the hydraulic buffer tank through the pre-outlet. When the electromagnetic coil assembly inside the coil housing receives the injection signal, the coil is energized to generate electromagnetic force, attracting the armature to move to the upper baffle position. At this time, the extrusion plate, along with the movement of the armature, will extrude the fuel stored in the hydraulic buffer tank, causing the fuel to flow through the guide channel into the unloading hole at the top of the pre-delivery pipe and be discharged into the pre-injection tank. The pre-injection tank is connected to the pre-injection pipe, and pre-injection is generated through the pre-nozzle. After the extrusion plate and the pre-outlet position coincide and close, the pre-injection ends. Step 3: Injection. After the armature moves to the upper baffle ring position, the distance between it and the electromagnetic coil assembly shortens. At this time, the attraction force increases, which drives the upper baffle ring to continue moving and drives the needle valve to move upward. At this time, the valve stem in the middle of the needle valve cancels the seal below the oil control groove, allowing the oil control groove to be connected with the nozzle. At this time, the upper oil pipe, lower oil pipe, and connecting pipe are connected to deliver the filtered fuel to the oil control groove and spray it out through the nozzle and spray hole. Step four: After the injection is completed, the electromagnetic coil assembly is de-energized, the needle valve is reset under the action of the reset spring, and the lower part of the oil control groove and the spray hole are resealed. The extrusion plate and armature are reset under the action of gravity.

[0016] Compared with the prior art, the beneficial effects of the present invention are: A hydraulic buffer tank and a pre-injection tank are set inside the lower housing. The lower oil pipe injects oil into the hydraulic buffer tank through the pre-outlet to form a buffer layer. As the electromagnetic coil assembly drives the armature to rise to the upper retaining ring, the extrusion plate squeezes the oil in the hydraulic buffer tank out through the pre-delivery pipe, the pre-injection tank, and the pre-injection pipe to form a pre-injection. This pre-injection gently increases the cylinder pressure before the main injection, greatly reducing the knocking sound caused by the violent combustion of fuel during the main injection. In addition, the buffer layer formed inside the hydraulic buffer tank can reduce the impact when the needle valve moves. Finally, the pre-nozzle is set at an angle below the injection hole, which can also wash away the carbon deposits attached to the injection hole, which has a triple advantage. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the main structure of the present invention; Figure 2 This is a schematic diagram of the main body structure of the present invention from a bottom view; Figure 3 This is a schematic diagram of the main body disassembled structure of the present invention; Figure 4 This is a schematic cross-sectional view of the main body structure of the present invention; Figure 5 For the present invention Figure 4 A magnified structural diagram at point A; Figure 6 For the present invention Figure 4 A magnified structural diagram at point B; Figure 7 For the present invention Figure 4 A magnified structural diagram at point C; Figure 8 This is a schematic diagram of the main body structure of the present invention in the pre-spraying state; Figure 9 For the present invention Figure 8 A magnified structural diagram at point D; Figure 10 This is a schematic cross-sectional view of the main body structure of the present invention in the main injection state; Figure 11 For the present invention Figure 10 A magnified structural diagram at point E; Figure 12 For the present invention Figure 10 A magnified structural diagram at point F.

[0018] In the diagram: 1. Upper housing; 11. Armature movable slot; 12. Armature; 13. Extrusion plate; 131. Support spring; 132. Guide channel; 14. Upper oil pipe; 2. Lower housing; 21. Hydraulic buffer channel; 22. Pre-delivery pipe; 23. Pre-injection channel; 24. Lower oil pipe; 241. Pre-outlet; 3. Valve seat; 31. Control channel; 32. Nozzle; 321. Spray hole; 33. Outer sleeve; 34. Connecting pipe; 35. Pre-injection pipe; 351. Pre-nozzle; 4. Needle valve; 41. Upper retaining ring; 42. Return spring; 5. Coil housing; 51. Electromagnetic coil assembly; 6. Oil inlet chamber; 61. Oil inlet pipe; 62. Upper filter channel; 63. Oil storage tank; 7. Sealing cover; 71. Guide shield; 711. Discharge port; 72. Filter cover; 721. Impurity storage ring. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clear and complete, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some, not all, embodiments of the present invention, and are merely illustrative of the embodiments of the present invention. They are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0020] Please see Figures 1 to 4 This invention provides a technical solution: a low-noise internal combustion engine fuel injector assembly, comprising an upper housing 1, a lower housing 2 fixedly mounted at the lower end of the upper housing 1, a coil housing 5 fixedly mounted at the upper end of the upper housing 1, a valve seat 3 fixedly mounted at the lower end of the lower housing 2, a needle valve 4 movably mounted inside the valve seat 3, and a sliding groove adapted to the needle valve 4 provided in the middle of both the lower housing 2 and the upper housing 1. An oil inlet 6 is fixedly mounted at the upper end of the coil housing 5, and an oil inlet valve is fixedly mounted on one side of the oil inlet 6. A sealing cover 7 is fixedly installed above the oil inlet 6. An upper filter trough 62 is provided inside the upper part of the oil inlet 6. An oil storage tank 63 is provided inside the lower part of the oil inlet 6. A flow guide 71 is fixedly installed below the sealing cover 7. A filter cover 72 is fixedly installed at the lower end of the flow guide 71. The flow guide 71 and the filter cover 72 are snapped together below the upper filter trough 62. Discharge ports 711 are evenly opened on the lower side wall of the flow guide 71. An impurity storage ring 721 is provided on the outer side of the filter cover 72. In this embodiment, the upper housing 1 and the lower housing 2 form a complete housing, the valve seat 3 and the needle valve 4 form a complete oil control valve, the sealing cover 7 seals the top of the oil inlet 6, and the sealing cover 7 connects the flow guide 71 and the filter cover 72 to facilitate the disassembly and cleaning of the filter cover 72. The oil inlet pipe 61 is connected to the common oil pipe of the oil pump, so that the fuel first enters the upper filter tank 62. A filter element can also be placed inside the upper filter tank 62. After the fuel is initially filtered by the filter element, it is guided by the flow guide 71 and discharged through the discharge port 711 to the top of the filter cover 72 for secondary filtration. The filtered pure fuel is temporarily stored in the oil storage tank 63, and impurities will enter the impurity storage ring 721 for temporary storage and waiting for subsequent cleaning. By filtering the impurities in the fuel, the precision components can be protected from wear and blockage. Example 2

[0021] Please see Figures 5 to 7 Based on Embodiment 1, this embodiment proposes that an upper oil pipe 14 is symmetrically fixedly installed on the inner wall of the upper housing 1, with the top end of the upper oil pipe 14 penetrating the bottom inner wall of the oil storage tank 63. A lower oil pipe 24 is symmetrically fixedly installed on the inner wall of the lower housing 2, with a pre-outlet 241 opened on the side wall of the lower oil pipe 24. The pre-outlet 241 is located inside the hydraulic buffer tank 21. The upper end of the lower oil pipe 24 is snapped into the lower end of the upper oil pipe 14. The lower oil pipe 24 penetrates the inner walls of both sides of the valve seat 3. An oil control groove 31 is provided in the middle of the valve seat 3. A connecting pipe 34 is symmetrically fixedly installed on both sides of 31. The upper end of the connecting pipe 34 is fixedly connected to the lower end of the lower oil pipe 24. An electromagnetic coil assembly 51 is fixedly installed inside the coil housing 5. An armature movable groove 11 is opened on the upper part of the upper housing 1. An armature 12 is slidably installed inside the armature movable groove 11. The armature 12 is slidably installed outside the needle valve 4. An upper retaining ring 41 is fixedly installed on the top of the needle valve 4. A return spring 42 is sleeved on the middle part of the needle valve 4. The upper end of the return spring 42 is fixedly connected to the lower middle part of the lower housing 2. In this embodiment, the coil housing 5 mainly serves to install the electromagnetic coil assembly 51. The upper oil pipe 14, lower oil pipe 24, and connecting pipe 34 form a complete oil delivery pipeline, connecting the oil storage tank 63 and the oil control tank 31. In the initial state, the return spring 42 presses the needle valve 4 inside the valve seat 3. At this time, the nozzle 321 is closed by the lower end of the needle valve 4, and the lower end of the oil control tank 31 is closed by the valve stem in the middle of the needle valve 4. At this time, the oil control tank 31 and the nozzle 32 are not connected. When the electromagnetic coil assembly 51 inside the coil housing 5 receives the oil injection signal, the coil is energized to generate electromagnetic force, attracting the armature 12 to move, thereby driving the needle valve 4 to move upward. At this time, the valve stem in the middle of the needle valve 4 releases the seal below the oil control groove 31, allowing the oil control groove 31 to connect with the nozzle 32. At this time, the upper oil pipe 14, the lower oil pipe 24, and the connecting pipe 34 are connected to deliver the filtered fuel to the oil control groove 31 and spray it out through the nozzle 32 and the spray hole 321. Finally, the electromagnetic coil assembly 51 is de-energized, and the needle valve 4 is reset under the action of the reset spring 42 to re-seal the area below the oil control groove 31 and the spray hole 321. The spray hole 321 is provided in two rows. The bottom row is completely sealed by the lower end of the needle valve 4, and the row near the top can completely discharge the fuel accumulated inside the nozzle 32 after the oil control groove 31 is sealed. Example 3

[0022] Please see Figures 8 to 12 Based on Embodiment 2, this embodiment proposes that a hydraulic buffer groove 21 is provided inside the upper part of the lower housing 2, and a pre-delivery pipe 22 is fixedly installed inside the hydraulic buffer groove 21. An oil discharge hole is provided at the top of the pre-delivery pipe 22. An extrusion plate 13 is provided inside the lower housing 2, and a support spring 131 is fixedly installed at the lower end of the extrusion plate 13. The extrusion plate 13 is slidably installed below the armature 12 through the support spring 131. A guide groove 132 is provided on the upper surface of the extrusion plate 13, and a pre-spraying oil is provided at the lower part of the interior of the lower housing 2. The lower end of the pre-injection tank 23 and the pre-delivery pipe 22 penetrate the top of the pre-injection tank 23. A nozzle 32 is provided inside the lower part of the valve seat 3. A spray hole 321 is opened at the bottom of the nozzle 32. The lower end of the needle valve 4 is in contact with the upper part of the spray hole 321. An outer sleeve 33 is fixedly installed on the lower outer side of the valve seat 3. A pre-injection pipe 35 is symmetrically fixedly installed in the middle of the outer sleeve 33. The upper end of the pre-injection pipe 35 penetrates the bottom of the pre-injection tank 23. A pre-nozzle 351 is provided at the lower end of the pre-injection pipe 35. The pre-nozzle 351 is located diagonally below the spray hole 321. In this embodiment, the lower oil pipe 24 pre-stores a small amount of fuel into the hydraulic buffer tank 21 through the pre-outlet 241. After the pre-stored fuel, the pre-injection tank 23 cooperates with the extrusion plate 13 to buffer the impact of the armature 12 and the needle valve 4. When the electromagnetic coil assembly 51 inside the coil housing 5 receives the injection signal, the coil is energized to generate electromagnetic force, attracting the armature 12 to move. The armature 12 first moves to the upper retaining ring 41 position. At this time, the extrusion plate 13, along with the movement of the armature 12, will extrude the fuel pre-stored in the hydraulic buffer tank 21, causing the fuel to flow through the guide groove 132 into the unloading hole at the top of the pre-delivery pipe 22 and be discharged into the pre-injection tank 23. The pre-injection tank 23 is connected to the pre-injection pipe 35 and generates pre-injection through the pre-nozzle 351. Before the main injection, the cylinder pressure is gradually increased, which greatly reduces the knocking sound caused by the violent combustion of fuel during the main injection. In addition, the buffer layer formed inside the hydraulic buffer tank 21 can reduce the impact of the needle valve 4 during movement. Finally, the pre-injection tank 23... The nozzle 351, positioned diagonally below the nozzle 321, can also wash away carbon deposits adhering to the nozzle 321. After the armature 12 moves to the position of the upper retaining ring 41, the distance between it and the electromagnetic coil assembly 51 shortens, increasing the attractive force and causing the upper retaining ring 41 to continue moving, driving the needle valve 4 to move upward. At this time, the valve stem in the middle of the needle valve 4 releases the seal below the oil control groove 31, allowing the oil control groove 31 to connect with the nozzle 32. At this time, the upper oil pipe 14, lower oil pipe 24, and connecting pipe 34 are connected to filter the oil. The fuel is delivered to the oil control tank 31 and sprayed out through the nozzle 32 and spray hole 321. When the armature 12 moves to the position of the upper baffle ring 41, the extrusion plate 13 moves to the upper hydraulic buffer tank 21 and coincides with the position of the pre-oil outlet 241 to close it. The pre-injection ends at this time to ensure the smooth progress of the main injection. As the armature 12 continues to move upward, the guide groove 132 is compressed. Finally, the needle valve 4 is reset under the action of the reset spring 42, and the extrusion plate 13 and the armature 12 are reset under the action of gravity. Example 4

[0023] Please see Figures 1 to 12 Based on Example 3, this example also proposes a method for using a low-noise internal combustion engine fuel injector assembly, including the following steps: Step 1: Fuel enters the fuel inlet chamber 6 through the fuel inlet pipe 61 for filtration, is guided by the flow guide 71 and discharged through the discharge port 711 to the top of the filter cover 72, and the filtered pure fuel is temporarily stored inside the fuel storage tank 63. Step 2, pre-injection: The lower oil pipe 24 pre-stores a small amount of fuel into the hydraulic buffer tank 21 through the pre-outlet 241. When the electromagnetic coil assembly 51 inside the coil housing 5 receives the injection signal, the coil is energized to generate electromagnetic force, attracting the armature 12 to move to the upper baffle ring 41. At this time, the extrusion plate 13, along with the movement of the armature 12, will extrude the fuel pre-stored in the hydraulic buffer tank 21, causing the fuel to flow through the guide groove 132 into the unloading hole at the top of the pre-delivery pipe 22 and be discharged into the pre-injection tank 23. The pre-injection tank 23 is connected to the pre-injection pipe 35, and pre-injection is generated through the pre-nozzle 351. After the extrusion plate 13 and the pre-outlet 241 are aligned and closed, the pre-injection ends. Step 3: Injection. After the armature 12 moves to the position of the upper baffle ring 41, the distance between it and the electromagnetic coil assembly 51 is shortened. At this time, the attraction force increases, which drives the upper baffle ring 41 to continue moving and drives the needle valve 4 to move upward. At this time, the valve stem in the middle of the needle valve 4 cancels the seal below the oil control groove 31, allowing the oil control groove 31 to be connected with the nozzle 32. At this time, the upper oil pipe 14, the lower oil pipe 24, and the connecting pipe 34 are connected to deliver the filtered fuel to the oil control groove 31 and spray it out through the nozzle 32 and the spray hole 321. Step four: After the spraying is completed, the electromagnetic coil assembly 51 is de-energized, the needle valve 4 is reset under the action of the reset spring 42, and the lower part of the oil control groove 31 and the spray hole 321 are sealed again. The extrusion plate 13 and the armature 12 are reset under the action of gravity.

[0024] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-noise internal combustion engine fuel injector assembly, comprising an upper housing (1), wherein a lower housing (2) is fixedly mounted on the lower end of the upper housing (1), characterized in that: The upper end of the upper housing (1) is fixedly installed with a coil housing (5), the lower end of the lower housing (2) is fixedly installed with a valve seat (3), a needle valve (4) is movably installed inside the valve seat (3), the middle of the lower housing (2) and the upper housing (1) are provided with a sliding groove adapted to the needle valve (4), the upper end of the coil housing (5) is fixedly installed with an oil inlet (6), and an oil inlet pipe (61) is fixedly installed on one side of the oil inlet (6).

2. The low-noise internal combustion engine fuel injector assembly according to claim 1, characterized in that: A closed cover (7) is fixedly installed on the top of the oil inlet (6), an upper filter groove (62) is provided inside the upper part of the oil inlet (6), and an oil storage tank (63) is provided inside the lower part of the oil inlet (6).

3. The low-noise internal combustion engine fuel injector assembly according to claim 2, characterized in that: A flow guide hood (71) is fixedly installed below the closed cover (7), and a filter hood (72) is fixedly installed at the lower end of the flow guide hood (71). The flow guide hood (71) and the filter hood (72) are snapped together and installed below the upper filter tank (62). Discharge ports (711) are evenly opened below the side wall of the flow guide hood (71), and an impurity storage ring (721) is provided on the outer side of the filter hood (72).

4. The low-noise internal combustion engine fuel injector assembly according to claim 1, characterized in that: The upper housing (1) is symmetrically fixedly installed with an upper oil pipe (14) on its inner side wall. The top end of the upper oil pipe (14) penetrates the bottom inner wall of the oil storage tank (63). The lower housing (2) is symmetrically fixedly installed with a lower oil pipe (24) on its inner side wall. The lower oil pipe (24) has a pre-outlet (241) on its side wall. The pre-outlet (241) is located inside the hydraulic buffer tank (21). The upper end of the lower oil pipe (24) is connected to the lower end of the upper oil pipe (14). The lower oil pipe (24) penetrates the inner walls of both sides of the valve seat (3). The valve seat (3) has an oil control groove (31) in the middle. The oil control groove (31) has a connecting pipe (34) symmetrically fixedly installed on both sides. The upper end of the connecting pipe (34) is fixedly connected to the lower end of the lower oil pipe (24).

5. The low-noise internal combustion engine fuel injector assembly according to claim 1, characterized in that: An electromagnetic coil assembly (51) is fixedly installed inside the coil housing (5). An armature movable groove (11) is provided above the upper housing (1). An armature (12) is slidably installed inside the armature movable groove (11). The armature (12) is slidably installed outside the needle valve (4). An upper retaining ring (41) is fixedly installed on the top of the needle valve (4). A return spring (42) is sleeved on the middle of the needle valve (4). The upper end of the return spring (42) is fixedly connected to the lower middle part of the lower housing (2).

6. The low-noise internal combustion engine fuel injector assembly according to claim 1, characterized in that: The lower housing (2) has a hydraulic buffer groove (21) inside its upper part. A pre-delivery pipe (22) is fixedly installed inside the hydraulic buffer groove (21). An oil discharge hole is opened at the top of the pre-delivery pipe (22). An extrusion plate (13) is provided inside the lower housing (2). A support spring (131) is fixedly installed at the lower end of the extrusion plate (13). The extrusion plate (13) is slidably installed below the armature (12) through the support spring (131). A guide groove (132) is opened on the upper surface of the extrusion plate (13).

7. A low-noise internal combustion engine fuel injector assembly according to claim 6, characterized in that: The lower housing (2) has a pre-spraying tank (23) located inside the lower part of the housing. The lower end of the pre-delivery pipe (22) passes through the top of the pre-spraying tank (23). The valve seat (3) has a nozzle (32) located inside the lower part of the housing. The nozzle (32) has a spray hole (321) at the bottom. The lower end of the needle valve (4) is in contact with the upper part of the spray hole (321).

8. A low-noise internal combustion engine fuel injector assembly according to claim 7, characterized in that: An outer sleeve (33) is fixedly installed on the lower outer side of the valve seat (3), and a pre-injection pipe (35) is symmetrically fixedly installed in the middle of the outer sleeve (33). The upper end of the pre-injection pipe (35) penetrates the bottom of the pre-injection groove (23).

9. A low-noise internal combustion engine fuel injector assembly according to claim 8, characterized in that: The lower end of the pre-injection pipe (35) is provided with a pre-nozzle (351), which is located obliquely below the injection hole (321).

10. A method of using a low-noise internal combustion engine fuel injector assembly, as described in any one of claims 1-9, characterized in that: The process includes the following steps: Step 1, fuel enters the fuel inlet chamber (6) through the fuel inlet pipe (61) for filtration, and is guided by the flow guide (71) and discharged through the discharge port (711) to the top of the filter cover (72). The filtered pure fuel is temporarily stored inside the fuel storage tank (63). Step 2, pre-injection: The lower oil pipe (24) pre-stores a small amount of fuel in the hydraulic buffer tank (21) through the pre-outlet (241). When the electromagnetic coil assembly (51) inside the coil housing (5) receives the injection signal, the coil is energized to generate electromagnetic force, attracting the armature (12) to move to the upper baffle (41) position. At this time, the extrusion plate (13) will extrude the fuel pre-stored in the hydraulic buffer tank (21) as the armature (12) moves, so that the fuel is guided through the guide groove (132) into the unloading hole at the top of the pre-delivery pipe (22) and discharged into the pre-injection tank (23). The pre-injection tank (23) is connected to the pre-injection pipe (35) and pre-injection is generated through the pre-nozzle (351). After the extrusion plate (13) and the pre-outlet (241) are aligned and closed, the pre-injection ends. Step 3, injection is performed. After the armature (12) moves to the position of the upper baffle ring (41), the distance between it and the electromagnetic coil assembly (51) is shortened. At this time, the attraction force increases, thereby driving the upper baffle ring (41) to continue moving and driving the needle valve (4) to move upward. At this time, the valve stem in the middle of the needle valve (4) cancels the closure of the lower part of the oil control groove (31), so that the oil control groove (31) and the nozzle (32) are connected. At this time, the upper oil pipe (14), the lower oil pipe (24), and the connecting pipe (34) are connected to deliver the filtered fuel to the oil control groove (31) and spray it out through the nozzle (32) and the spray hole (321). Step 4: After the spraying is completed, the electromagnetic coil assembly (51) is de-energized, the needle valve (4) is reset under the action of the reset spring (42) to re-close the area below the oil control groove (31) and the spray hole (321), and the extrusion plate (13) and armature (12) are reset under the action of gravity.

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