Diesel and methanol dual-fuel injector

Abstract

The utility model provides a diesel oil and methanol dual-fuel injector. The diesel oil and methanol dual-fuel injector comprises an injector body, a first pressure regulating spring, a range limiting disc and a needle valve matching part, the ejector body is provided with a first hollow cavity penetrating through the two ends. A first pressure adjusting spring is arranged in the first hollow cavity, and a diesel oil inlet way is arranged on one side of the ejector body. The range limiting disc is provided with a second hollow cavity; the ejector rod is arranged on the second hollow cavity; the lower end of the third hollow cavity serves as a methanol nozzle. The diesel and methanol dual-fuel injector structure is provided through the oil paths on the injector body, the range limiting disc and the needle valve matching part, and the technical problem that a diesel and methanol dual-fuel injector is lacked in the prior art is solved.

Description

Technical field:

[0001] The utility model relates to the field of injectors, in particular to a diesel and methanol dual-fuel injector. Background technology:

[0002] With the national vision of "carbon peak and carbon neutrality", it is a general trend to vigorously develop green and low-carbon technologies. The value chain of new energy and low-carbon technologies will become a top priority, and the ship power industry has also ushered in new development opportunities. Traditional diesel engines have gradually lost their competitiveness because of their high C, H and particulate matter emissions after use. Major research institutes or universities are vigorously developing low / zero carbon power equipment such as methanol, ammonia, and hydrogen.

[0003] The fuel injection system is the core of the engine. In the context of "dual carbon", the methanol fuel injection system is highly favored. However, due to the characteristics of methanol fuel, it is difficult to directly compress and ignite, and diesel ignition is required. This requires adding a diesel micro-injection system to the engine, which brings great difficulties to the already compact engine structure layout. At the same time, there are also shortcomings such as complex system structure, low reliability, and limited micro-injection capacity. The diesel-methanol dual-fuel integrated solution can make up for the shortcomings of the two independent systems and reduce the difficulty of structural layout. At the same time, considering the toxicity and easy mixing and explosion of methanol fuel, zero leakage structural design should be considered as much as possible.

[0004] Therefore, a diesel-methanol dual-fuel injector is urgently needed to help solve the technical problem of lacking a diesel-methanol dual-fuel injector in the prior art. Utility model content:

[0005] In one embodiment, the utility model provides a diesel-methanol dual-fuel injector, which provides a diesel-methanol dual-fuel injector structure through the oil circuit on the injector body, the limiter disk, and the needle valve pair, helping to solve the technical problem of the lack of a diesel-methanol dual-fuel injector in the prior art.

[0006] The diesel-methanol dual-fuel injector comprises an injector body, a first pressure regulating spring, a travel limiter, and a needle valve pair;

[0007] The injector body has a first hollow cavity running through both ends;

[0008] The first pressure regulating spring is arranged in the first hollow cavity, one end of the first pressure regulating spring abuts against a push rod on the first pressure regulating spring, and a diesel oil inlet passage is arranged on one side of the injector body;

[0009] One end of the stroke-limiting disc abuts against the injector body. The stroke-limiting disc has a second hollow cavity which penetrates through the stroke-limiting disc and one end of which is docked with the first hollow cavity. The ejector rod (21) is arranged in the second hollow cavity (31).

[0010] The needle valve pair abuts against the other end of the stroke-limiting disc. The needle valve pair has the third hollow cavity which penetrates through both ends of the needle valve pair. The needle valve is arranged in the third hollow cavity. The upper end of the third hollow cavity is communicated with the methanol inlet oil path of the injector body through the stroke-limiting disc, and the lower end of the third hollow cavity serves as the methanol injection port.

[0011] In one embodiment, a slide valve is arranged in the third hollow cavity of the needle valve pair. The top of the slide valve abuts against the second pressure-regulating spring on the bottom surface of the stroke-limiting disc. A pressure space is formed at the lower end of the needle valve. After methanol is introduced into the pressure space through the methanol inlet oil path to reach a predetermined pressure, the slide valve is lifted to realize methanol injection.

[0012] In one embodiment, a fourth hollow cavity is arranged in the middle of the needle valve pair. The fourth hollow cavity penetrates through both ends of the needle valve pair, and a needle valve is arranged in the fourth hollow cavity.

[0013] An elastic member filling groove is arranged on the stroke-limiting disc at the position where the slide valve abuts against the stroke-limiting disc. A second pressure-regulating spring is arranged in the elastic member filling groove to provide pressure on the slide valve. Methanol passes through the methanol inlet oil path to the pressure space to lift the slide valve and then spray out from the end.

[0014] In one embodiment, a fifth hollow cavity is arranged on the injector body. One end of the fifth hollow cavity is used for entering sealing oil, and the other end of the fifth hollow cavity leads to a sealing oil ring arranged on the top end surface of the needle valve pair.

[0015] In one embodiment, the slide valve is of a cylindrical structure, and a plurality of oil through holes are arranged on its outer circle. The sealing oil enters the oil through holes through an oil path to form a seal.

[0016] In one embodiment, a pressure-regulating gasket is further arranged in the elastic member filling groove.

[0017] In one embodiment, the contact surface between the needle valve and the lower end of the fourth hollow cavity, and the contact surface between the slide valve and the lower end of the third hollow cavity are conical surfaces.

[0018] In one embodiment, the diesel-methanol dual fuel injector further includes a diesel inlet pipe and a methanol inlet pipe.

[0019] One end of the diesel inlet pipe is inserted into the injector body to form the diesel inlet oil path.

[0020] One end of the methanol inlet pipe is inserted into the injector body to form the methanol inlet oil path.

[0021] In one embodiment, a leakage return hole is provided on the methanol inlet pipe. The leakage return hole penetrates both ends of the methanol inlet pipe. One end of the leakage return hole is connected to the contact surface between the methanol inlet pipe and the injector body, and the contact surface is a conical surface.

[0022] In one embodiment, the injector body is of a cylindrical structure and is sleeved with a sealing ring. Description of the drawings:

[0023] Figure 1 It is a schematic cross-sectional structure diagram of one side of a diesel-methanol dual-fuel injector in an embodiment of the present invention;

[0024] Figure 2 It is a schematic cross-sectional structure diagram of the other side of a diesel-methanol dual-fuel injector in another embodiment of the present invention;

[0025] Figure 3 It is a schematic structure diagram of the injector body in another embodiment of the present invention;

[0026] Figure 4 It is a schematic cross-sectional structure diagram of one side of the needle valve assembly in another embodiment of the present invention;

[0027] Figure 5 It is a schematic cross-sectional structure diagram of the other side of the needle valve assembly in another embodiment of the present invention;

[0028] Figure 6 It is a schematic external structure diagram of the needle valve assembly in another embodiment of the present invention;

[0029] Figure 7 It is a schematic external structure diagram of the stroke limiter plate in another embodiment of the present invention;

[0030] Figure 8 It is a schematic cross-sectional structure diagram of one side of the stroke limiter plate in another embodiment of the present invention;

[0031] Figure 9 It is a schematic cross-sectional structure diagram of the other side of the stroke limiter plate in another embodiment of the present invention;

[0032] Figure 10 It is a schematic cross-sectional structure diagram of the spool valve in another embodiment of the present invention;

[0033] Figure 11 It is a schematic external structure diagram of the spool valve in another embodiment of the present invention.

[0034] Reference numerals:

[0035] Injector body 1

[0036] First hollow cavity 11

[0037] Diesel fuel inlet oil path 12

[0038] Methanol fuel inlet oil path 13

[0039] First pressure regulating spring 2

[0040] Ejector rod 21

[0041] Stroke limiting disc 3

[0042] Second hollow cavity 31

[0043] Elastic member filling groove 32

[0044] Second pressure regulating spring 33

[0045] Ejector rod 4

[0046] Adjusting screw 5

[0047] Slide valve 6

[0048] Needle valve couple 7

[0049] Third hollow cavity 71

[0050] Needle valve 72

[0051] Oil passage hole 721

[0052] Pressure space 73

[0053] Pressure regulating gasket 8

[0054] Diesel fuel inlet pipe 9

[0055] Methanol fuel inlet pipe 10

[0056] Leakage return oil hole 101

[0057] Sealing ring 102

[0058] Tightening cap 100 Specific implementation method:

[0059] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0060] Figure 1 This is a schematic cross-sectional view of one side of a diesel-methanol dual-fuel injector in an embodiment of the present utility model; Figure 2 This is a schematic cross-sectional view of the other side of a diesel-methanol dual-fuel injector in another embodiment of the present utility model; Figure 3 This is a schematic structural view of the injector body in another embodiment of the present utility model; Figure 4 This is a schematic cross-sectional view of one side of the needle valve assembly in another embodiment of the present utility model; Figure 5 This is a schematic cross-sectional view of the other side of the needle valve assembly in another embodiment of the present utility model; Figure 6 This is a schematic external view of the needle valve assembly in another embodiment of the present utility model; Figure 7 This is a schematic external view of the stroke limiter plate in another embodiment of the present utility model; Figure 8 This is a schematic cross-sectional view of one side of the stroke limiter plate in another embodiment of the present utility model; Figure 9 This is a schematic cross-sectional view of the other side of the stroke limiter plate in another embodiment of the present utility model; Figure 10 This is a schematic cross-sectional view of the spool valve in another embodiment of the present utility model; Figure 11 This is a schematic external view of the spool valve in another embodiment of the present utility model.

[0061] As Figures 1 to 11 shown, in one embodiment, the present utility model provides a diesel-methanol dual-fuel injector, and the diesel-methanol dual-fuel injector includes an injector body 1, a first pressure regulating spring 2, a stroke limiter plate 3, a push rod 21, and a needle valve assembly 7;

[0062] The injector body 1 has a first hollow cavity 11 running through both ends;

[0063] The first pressure regulating spring 2 is arranged in the first hollow cavity 11, one end of the first pressure regulating spring 2 abuts against the push rod 21 on the first pressure regulating spring 2, and a diesel fuel inlet oil path 12 is arranged on one side of the injector body 1;

[0064] One end of the limit disc 3 abuts against the injector body 1 , and the limit disc 3 has a second hollow cavity 31 , which passes through the limit disc 3 and one end of which is connected to the first hollow cavity 11 , and the two are connected after the connection, and the push rod 21 is arranged in the second hollow cavity 31 .

[0065] The push rod 21 is arranged on the second hollow cavity 31, and is used for pushing the second hollow cavity 31;

[0066] The needle valve pair 7 abuts against the other end of the limit disc 3, and the needle valve pair 7 has a third hollow cavity 71, which runs through both ends of the needle valve pair 7. A needle valve 6 is arranged in the third hollow cavity 71, and the upper end of the third hollow cavity 71 is connected to the methanol oil inlet path 13 of the injector body 1 through the limit disc 3, and the lower end of the third hollow cavity 71 serves as a methanol nozzle.

[0067] In the present embodiment, a specific structure of the diesel-methanol dual-fuel injector is provided, and diesel and methanol fuels are respectively sprayed out through the lower end of the needle valve pair 7 through the diesel oil inlet line 12 and the methanol oil inlet line 13. The injector body 1, the limit plate 3 and the needle valve pair 7 preferably adopt a columnar structure. The needle valve 6 is initially in a state of being supported from top to bottom, that is, from the injector body 1 to the needle valve pair 7 due to the influence of the first pressure regulating spring 2. When the pressure of the diesel under the needle valve 6 exceeds the predetermined pressure value, the needle valve 6 will be lifted in the reverse direction. At this time, the diesel will be sprayed out from the diesel spray hole originally supported by the lower end of the needle valve 6. The first pressure regulating spring 2 can adjust the pressure of the needle valve 6, thereby adjusting the diesel pressure at which the needle valve 6 can be lifted. At the same time, the injection of methanol fuel is achieved through the methanol oil inlet line 13, which helps to solve the technical problem of lack of a diesel-methanol dual-fuel injector in the prior art.

[0068] In addition to the first pressure-regulating spring 2 installed above the needle valve 6, a push rod 4 is also arranged above it. An opening is arranged on the side of the push rod 4, and a middle section is formed to leave space for the diesel oil inlet passage 12 to enter from one side. In other words, no matter how the push rod 4 moves up and down, it will not affect the access to the diesel oil inlet passage 12.

[0069] An adjusting screw 5 is arranged above the push rod 4. The adjusting screw 5 is fixedly connected to the injector body 1 by a thread. The top of the adjusting screw 5 extends out of the injector body 1 so that the position of the push rod 4 can be easily adjusted by rotating from the outside. When the push rod 4 moves downward, it will press on the first pressure-adjusting spring 2 to increase the downward pressure of the first pressure-adjusting spring 2, and vice versa, the pressure will be reduced.

[0070] In one embodiment, a spool valve 72 is disposed within a third hollow cavity 71 of the needle valve pair 7. The top of the spool valve 72 abuts against the bottom surface of a second pressure regulating spring 33 of the stroke limiting disc 3, with a certain gap provided for the up and down movement of the spool valve. The lower end of the spool valve 72 has a pressure space 73. When methanol is introduced into the pressure space 73 through the methanol inlet oil passage 13 and reaches a predetermined pressure, the spool valve 72 is lifted to achieve methanol injection.

[0071] In this embodiment, a specific structure of the needle valve pair 7 is provided. The specific introduction path of the methanol inlet oil passage 13 will be described in detail later and will not be elaborated here.

[0072] In one embodiment, an elastic member filling groove 32 is provided at the position where the needle valve pair 7 abuts against the stroke limiting disc 3. A second pressure regulating spring 33 is disposed within the elastic member filling groove 32 to provide a fixed pressure for the spool valve 72. It should be noted that the elastic member filling groove 32 is exactly located directly above the spool valve 72.

[0073] In this embodiment, a specific implementation structure for controlling the pressure lift at the end of the spool valve 72 is further provided.

[0074] In one embodiment, a fifth hollow cavity 75 is provided on the injector body 1. One end of the fifth hollow cavity 75 is for the entry of sealing oil, and the other end of the fifth hollow cavity 75 leads to a sealing oil ring 76 provided on the top end face of the needle valve pair 7.

[0075] In this embodiment, a specific sealing structure of the injector body 1 is provided, with two inner and outer sealing oil rings 76.

[0076] In one embodiment, the spool valve 72 is of a cylindrical structure, and a plurality of oil through holes 721 are provided on its outer circumference. The sealing oil enters the oil through holes 721 through an oil passage to form a seal.

[0077] In this embodiment, a specific sealing structure of the spool valve 72 is provided.

[0078] In one embodiment, a pressure regulating gasket 8 is further disposed within the elastic member filling groove 32.

[0079] In this embodiment, a specific implementation manner with a pressure regulating gasket 8 is provided.

[0080] In one embodiment,

[0081] The contact surface between the spool valve 72 and the lower end of the third hollow cavity 71, and the contact surface between the needle valve 6 and the lower end of the third hollow cavity 71 are conical surfaces.

[0082] In this embodiment, a structure with a conical contact surface is provided to improve the sealing degree through the conical surface and make it easier to establish pressure.

[0083] In one embodiment, the diesel-methanol dual-fuel injector further includes a diesel fuel inlet pipe 9 and a methanol fuel inlet pipe 10;

[0084] One end of the diesel fuel inlet pipe 9 is inserted into the injector body 1 to form a diesel fuel inlet passage 12;

[0085] One end of the methanol oil inlet pipe 10 is inserted into the injector body 1 to form a methanol oil inlet passage 13 .

[0086] In this embodiment, a specific implementation method of how to form the diesel fuel inlet passage 12 and the methanol fuel inlet passage 13 is provided.

[0087] In one embodiment, a leakage oil return hole 101 is provided on the methanol oil inlet pipe 10, and the leakage oil return hole 101 passes through both ends of the methanol oil inlet pipe 10. One end of the leakage oil return hole 101 is connected to the contact surface between the methanol oil inlet pipe 10 and the injector body 1, and the contact surface is a conical surface.

[0088] In this embodiment, a specific implementation method of how the leakage oil return hole 101 forms an oil return path is provided.

[0089] In one embodiment, the injector body 1 is a columnar structure and is sleeved with a sealing ring 102 .

[0090] In this embodiment, a specific implementation of the sealing ring 102 of the injector body 1 is provided.

[0091] Based on the above structure, the paths of diesel, methanol and sealing oil are described in detail as follows:

[0092] The diesel oil circuit starts from the diesel oil inlet pipe 9. The diesel oil inlet circuit 12 is a channel path formed inside the diesel oil inlet pipe 9. It is then inserted into the internal channel 1d connected at one end through the diesel oil inlet pipe 9, and then continues to be conducted downward through the pipeline 7g, and then continues downward through 801j to finally enter 801L, and then to 802a. At this time, the diesel has entered the position to be injected, and its oil pressure is balanced with the needle valve 6 above under the action of the first pressure regulating spring 2. Only when the oil pressure is greater than the pressure provided by the first pressure regulating spring 2 will the needle valve 6 be pushed open. In this way, the diesel will eventually reach the end and be injected through the spray hole 801d and injected into the cylinder.

[0093] The path of methanol is similar to that of diesel fuel. It starts from the methanol fuel inlet pipe 10. The diesel fuel inlet pipe 12 is a channel path formed inside the body of the methanol fuel inlet pipe 10. It enters the hole 7h below from the pipe 1g, and then goes to 801k and 801m, and enters the area to be injected 801c, where 801k is the methanol pipeline hole, and the corresponding 801m is the reserved space at the bottom of the methanol pipeline hole, 801c is the bottom of the methanol pipeline hole, 803a is the methanol end reserved space at the bottom of the needle valve pair 7, and 801e is the injection hole set outward from the methanol end reserved space, which is evenly distributed along the circumference. The second pressure regulating spring 33 regulates the pressure when the slide valve 72 is lifted. When the pressure of methanol is greater than the pressure provided by the second pressure regulating spring 33, methanol lifts the slide valve 72 and is injected into the cylinder through the injection hole 801e. For injecting methanol as the main fuel, the first and second injection holes form a certain angle with the injector axis, which is more convenient for the fuel to be fully mixed and ignited.

[0094] In addition to the above-mentioned diesel and methanol paths, there is also a corresponding structure for sealing oil (which also takes into account lubrication).

[0095] Specifically, it has two oil circuits;

[0096] The first oil circuit starts from the 1h oil circuit, supplies oil to the 7d annular cavity, and then passes through the 7f to the 801g annular cavity, forming a seal at the 7d and 801g annular cavities, which is used to prevent methanol leakage caused by failure of the high-pressure sealing surface between the limiter disc 3 and the injector body 1, and between the limiter disc 3 and the needle valve pair 7.

[0097] Another oil circuit also starts from the 1h oil circuit, goes to the 7d annular cavity, and then enters the 801f annular cavity through the 7e channel for sealing to prevent diesel leakage caused by failure of the high-pressure sealing surface of the limit plate 3 and the needle valve pair 7. At the same time, the sealing oil of the annular cavity 801f enters the 801h annular cavity from 801i-803b, where the methanol leaked from the sealing gaps 8b and 8c between the sliding valve 803 and the needle valve body 801 is sealed to achieve zero leakage of methanol, and at the same time, the sliding valve 803 is lubricated. The second pressure regulating spring is stored in 7c.

[0098] An O-ring 10c is installed on the methanol oil inlet pipe 10, which cooperates with the preset methanol oil inlet pipe connection mounting hole 1e on the injector body 1 to form a seal, preventing methanol leaking from the second matching cone surface 1f seal from leaking to the outside of the injector. At the same time, a leakage return oil hole 10b is provided on the methanol oil inlet pipe connection 10, one end of which is connected to the chamber 10a between the ball head-cone sealing ring belt and the O-ring 10c, and the other end is connected to the methanol oil inlet pipe connection end face 10d, so as to facilitate the abnormal leakage of methanol at the ball head-cone sealing ring belt to be led out for centralized treatment.

[0099] The injector can achieve the co-injection of diesel and methanol dual fuels. Diesel is injected from the first injection hole 801d as the pilot fuel, and methanol is injected from the second injection hole 801e as the main fuel. The diesel and methanol dual fuels can achieve better mixing and ignition, and zero leakage of methanol fuel can be achieved through the internal sealing of the injector with sealing oil.

[0100] The specific implementation process is as follows: Through the combined design of the needle valve 802 and the spool valve 803, the methanol fuel passage and the micro-injection diesel passage are respectively set. The methanol fuel passage can independently achieve the injection of methanol fuel, and the micro-injection diesel passage can independently achieve the injection of micro-injection fuel. The two do not affect each other and are completely independent. The micro-injection diesel is injected in the inner circle, and the methanol fuel is injected in the outer circle, which can achieve a better mixing effect and is also more convenient for the micro-injection fuel to ignite the main fuel, greatly simplifying the structure of the fuel injection system of the methanol fuel engine and at the same time reducing the difficulty of the structural layout of the methanol fuel engine.

[0101] Beneficial effects:

[0102] (1) In this solution, the inlets and fuel passages of methanol and diesel are respectively set in the injector body, and combined with the combined setting of the needle valve body, spool valve and needle valve, and through the matching of independent spring pressure regulating structures, two completely independent fuel injection systems are formed and integrated into one. The diesel fuel and methanol fuel can both achieve independent injection, and the two do not affect each other, and the overall structure of the injector is more compact, which is convenient for the overall structural layout of the engine.

[0103] (2) In this solution, the diesel as the pilot fuel is injected from the inner circle injection hole, and the methanol as the main fuel is injected from the outer peripheral injection hole, forming two concentric annular atomized fuels. On the one hand, it is convenient for the uniform mixing of the main fuel and the pilot fuel, and there is no phenomenon of uneven mixture concentration. On the other hand, it is also convenient for the pilot fuel to better ignite the main fuel.

[0104] (3) In this solution, a sealing oil passage is set. By introducing the sealing oil into the annular grooves formed by the mating of the high-pressure sealing surfaces between the injector body, the limit disc and the needle valve assembly, a sealing ring cavity is formed, which can effectively prevent abnormal leakage caused by the failure of the high-pressure sealing surfaces between the injector body, the limit disc and the needle valve assembly. In addition, at the same time, the sealing oil is introduced into the clearance seal formed by the spool valve and the needle valve body to effectively prevent the leakage of methanol fuel caused by the clearance between the spool valve and the needle valve body.

[0105] (4) In this solution, a leakage oil passage is provided inside the methanol inlet pipe connection. It is connected from the chamber between the sealing ring belt formed by the cooperation of the methanol inlet pipe connection and the injector body and the O-ring to the end face of the methanol inlet pipe connection, facilitating the centralized treatment of the abnormally leaked methanol at the sealing ring belt where the methanol inlet pipe connection and the injector body are fitted. At the same time, an O-ring is provided at the fitting hole between the methanol inlet pipe connection and the injector body to prevent the methanol fuel that has not flowed away through the leakage oil passage in time from leaking to the outside of the injector.

[0106] (5) In this solution, through the internal sealing of the injector body, the stroke limiting disc and the needle valve assembly by the sealing oil and the external anti-leakage measures for the methanol fuel at the methanol inlet pipe connection, zero leakage of the methanol fuel of the diesel-methanol dual-fuel injector can be achieved.

[0107] The above-described embodiments only represent some embodiments of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A diesel methanol dual fuel injector, characterized in that: The diesel methanol dual fuel injector comprises: An injector body (1) having a first hollow cavity (11) running through both ends; a first pressure regulating spring (2) disposed in the first hollow cavity (11), one end of the first pressure regulating spring (2) abutting against a push rod (21) on the first pressure regulating spring (2), and a diesel oil inlet passage (12) being disposed on one side of the injector body (1); a limit plate (3), one end of which abuts against the injector body (1); the limit plate (3) has a second hollow cavity (31); the second hollow cavity (31) penetrates the limit plate (3) and one end of which abuts against the first hollow cavity (11); the ejector rod (21) is arranged in the second hollow cavity (31); A needle valve pair (7) is abutted against the other end of the limit disc (3). The needle valve pair (7) has a third hollow cavity (71) that runs through both ends of the needle valve pair (7). The needle valve (6) is arranged in the third hollow cavity (71). The upper end of the third hollow cavity (71) is connected to the methanol oil inlet passage (13) of the injector body (1) through the limit disc (3). The lower end of the third hollow cavity (71) serves as a methanol nozzle.

2. The diesel-methanol dual fuel injector according to claim 1, characterized in that: A slide valve (72) is arranged in the third hollow cavity (71) of the needle valve pair (7). The top of the slide valve (72) abuts against the second pressure regulating spring (33) on the bottom surface of the limit plate (3). The lower end of the slide valve (72) has a pressure space (73). When the methanol inlet oil circuit (13) introduces methanol into the pressure space (73) and reaches a predetermined pressure, the slide valve (72) is lifted to realize methanol injection.

3. The diesel-methanol dual fuel injector according to claim 2, characterized in that: An elastic member filling groove (32) is provided at the position where the needle valve pair (7) and the limit disc (3) abut against each other, and a second pressure regulating spring (33) is provided in the elastic member filling groove (32) to provide a fixed pressure on the slide valve (72).

4. The diesel-methanol dual fuel injector according to claim 3, characterized in that: The injector body (1) is provided with a fifth hollow cavity (75), one end of which is used for the entry of sealing oil, and the other end of which leads to the top end surface of the needle valve pair (7) on which a sealing oil ring (76) is provided.

5. The diesel-methanol dual fuel injector according to claim 4, characterized in that: The slide valve (72) is a cylindrical structure, and a plurality of oil holes (721) are arranged on its outer ring. The sealing oil enters the oil holes (721) through the oil path to form a seal.

6. The diesel-methanol dual fuel injector according to claim 5, characterized in that: A pressure regulating gasket (8) is also arranged in the elastic member filling groove (32).

7. The diesel-methanol dual fuel injector according to claim 6, characterized in that: The contact surface between the slide valve (72) and the lower end of the third hollow cavity (71), and the contact surface between the needle valve (6) and the lower end of the third hollow cavity (71) are conical surfaces.

8. The diesel-methanol dual fuel injector according to claim 7, characterized in that: The diesel methanol dual fuel injector also includes: a diesel oil inlet pipe (9), one end of which is inserted into the injector body (1) to form the diesel oil inlet passage (12); A methanol oil inlet pipe (10) has one end inserted into the injector body (1) to form the methanol oil inlet passage (13).

9. The diesel-methanol dual fuel injector according to claim 8, characterized in that: The methanol oil inlet pipe (10) is provided with an oil leakage return hole (101), the oil leakage return hole (101) passes through both ends of the methanol oil inlet pipe (10), one end of the oil leakage return hole (101) is connected to the contact surface between the methanol oil inlet pipe (10) and the injector body (1), and the contact surface is a conical surface.

10. The diesel-methanol dual fuel injector according to claim 9, characterized in that: The injector body (1) is a columnar structure and is sleeved with a sealing ring (102).

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