Gas injector and engine

Abstract

The present invention relates to the field of engine technology, and specifically discloses a gas injector and an engine, wherein the gas injector comprises a metal heat-conducting sleeve, a needle valve body, and a heat-transfer fluid. The needle valve body is inserted into the cavity of the metal heat-conducting sleeve, and the positioning step is in contact with the positioning surface, so that the needle valve body is in direct contact with the metal heat-conducting sleeve, thereby achieving the purpose of directly transferring heat from the needle valve body to the metal heat-conducting sleeve; the heat-transfer fluid is arranged between the inner wall of the metal heat-conducting sleeve cavity and the outer wall of the needle valve body. With such an arrangement, the heat of the needle valve body is quickly transferred to the metal heat-conducting sleeve by using the heat-transfer fluid. In the gas injector of the present invention, the heat of the needle valve body can be quickly transferred to the metal heat-conducting sleeve and the heat-transfer fluid. The heat-transfer fluid eventually transfers the heat to the metal heat-conducting sleeve, and then the metal heat-conducting sleeve transfers the heat to the cooling water in the engine cylinder head, taking the heat out of the engine, ensuring a relatively stable operating temperature of the needle valve body, extending the service life, and reducing replacement costs.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a gas injector and an engine. Background Art

[0002] The needle valve body is a crucial component of the needle valve assembly, a crucial part of internal combustion engine injectors. The needle valve body of an internal combustion engine injector is subjected to high thermal loads from the high-temperature combustion gases within the engine. This thermal load is a key factor limiting the lifespan of the needle valve. High temperature loads reduce the material's wear resistance, leading to increased wear of the components. Currently, direct-injection gas injectors are gradually replacing port injectors due to the high thermal efficiency offered by direct injection.

[0003] Due to the low density of the gas, direct-injection gas injectors remove less heat from the needle valve body during injection, resulting in a significantly higher thermal load on the injector than on fuel injectors. Fuel injectors are lubricated by oil, while gas engines experience dry friction, resulting in more severe wear. Furthermore, gas engines produce less efficient combustion than fuel engines, resulting in higher exhaust temperatures after combustion, further exacerbating the thermal load on the gas injector. Therefore, it is necessary to design a method to reduce the thermal load on the needle valve body in direct-injection gas injectors. Summary of the Invention

[0004] The object of the present invention is to provide a gas injector and an engine to solve the problem in the prior art that the heat load of the needle valve body in the cylinder direct injection gas injector is high, resulting in a short service life of the needle valve body.

[0005] On the one hand, the present invention provides a gas injector, which includes: a metal heat-conducting sleeve, the metal heat-conducting sleeve having a positioning surface in its cavity, the metal heat-conducting sleeve can be installed in an engine cylinder head and exchange heat with cooling water in the engine cylinder head; a needle valve body, the needle valve body having a positioning step, the needle valve body is inserted into the cavity of the metal heat-conducting sleeve, the positioning step abutting the positioning surface; a heat transfer fluid is arranged between the inner wall of the metal heat-conducting sleeve cavity and the outer wall of the needle valve body, the heat transfer fluid can transfer heat from the needle valve body to the metal heat-conducting sleeve.

[0006] As an optional technical solution for the gas injector, the outer wall of the needle valve body is provided with a material reduction groove, which extends along the axial direction of the needle valve body.

[0007] As an optional technical solution for the gas injector, there are multiple material reduction grooves, and the multiple material reduction grooves are arranged at intervals along the circumference of the needle valve body.

[0008] As an optional technical solution for the gas injector, the needle valve body includes a first cylinder, a second cylinder and a third cylinder connected in sequence, the diameter of the first cylinder is larger than the diameter of the second cylinder, the diameter of the second cylinder is larger than the diameter of the third cylinder, a positioning step is formed between the second cylinder and the third cylinder, and the outer wall of the second cylinder has a material reduction groove.

[0009] As an optional technical solution for the gas injector, the inner wall of the first cylinder has a first limiting surface, and the inner wall of the second cylinder has a second limiting surface. Both the first limiting surface and the second limiting surface can cooperate with the needle valve spring.

[0010] As an optional technical solution for the gas injector, the metal thermally conductive sleeve includes a first sleeve, a second sleeve and a third sleeve connected in sequence. The diameter of the first sleeve is larger than the diameter of the second sleeve, the diameter of the second sleeve is larger than the diameter of the third sleeve, and the third sleeve has a positioning surface. The second column and the third column are inserted into the third sleeve. The gap between the second column and the third sleeve is 0.01mm-5mm. The third sleeve can be installed on the engine cylinder head.

[0011] As an optional technical solution for the gas injector, the third sleeve includes a first section and a second section connected to each other, the inner diameter of the first section is larger than the inner diameter of the second section to form a positioning surface, the outer wall of the second section has an external thread, and the mounting hole of the engine cylinder head has an internal thread. The external thread and the internal thread cooperate to connect the metal heat-conducting sleeve and the engine cylinder head.

[0012] As an optional technical solution for the gas injector, the heat transfer fluid is a paste grease or vaseline.

[0013] As an optional technical solution for the gas injector, the gas injector also includes an injector body, a tight cap, a first seal and a second seal. The tight cap is arranged in the cavity of the metal heat-conducting sleeve, a portion of the injector body is located in the cavity of the metal heat-conducting sleeve, the needle valve body is connected to the injector body through the tight cap, the first seal is arranged between the outer wall of the needle valve body and the inner wall of the injector body, and is used to seal the gap between the needle valve body and the injector body, and the second seal is arranged between the outer wall of the injector body and the inner wall of the metal heat-conducting sleeve, and is used to seal the gap between the injector body and the metal heat-conducting sleeve.

[0014] As an optional technical solution for the gas injector, the gas injector further includes a metal gasket, which is arranged between the positioning step and the positioning surface. The metal gasket can transfer the heat of the needle valve body to the metal heat-conducting sleeve.

[0015] On the other hand, the present invention provides an engine, comprising an engine cylinder head and the gas injector according to any of the above solutions, wherein the metal heat-conducting sleeve of the gas injector is installed on the engine cylinder head.

[0016] The beneficial effects of the present invention are:

[0017] The present invention provides a gas injector, comprising a metal heat-conducting sleeve, a needle valve body, and a heat transfer fluid. The needle valve body is inserted into the cavity of the metal heat-conducting sleeve, with the positioning step abutting the positioning surface. This allows the needle valve body to directly contact the metal heat-conducting sleeve, thereby achieving the purpose of directly transferring heat from the needle valve body to the metal heat-conducting sleeve, thereby improving the cooling effect of the needle valve body. At the same time, the heat transfer fluid is disposed between the inner wall of the metal heat-conducting sleeve cavity and the outer wall of the needle valve body. This arrangement allows the heat from the needle valve body to be quickly transferred to the metal heat-conducting sleeve using the heat transfer fluid. Compared to heat transfer through air, this method further improves the cooling effect of the needle valve body. Using the gas injector of the present invention, the heat of the needle valve body can be quickly transferred to the metal heat-conducting sleeve and the heat transfer fluid. The heat transfer fluid ultimately transfers the heat to the metal heat-conducting sleeve, which then transfers the heat to the cooling water in the engine cylinder head, removing the heat from the engine. This ensures a relatively stable operating temperature of the needle valve body, extends its service life, and reduces replacement costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a cross-sectional view of a gas injector according to an embodiment of the present invention;

[0019] Figure 2 Schematic diagram of the structure of the needle valve body in an embodiment of the present invention;

[0020] Figure 3 is a cross-sectional view of a needle valve body in an embodiment of the present invention;

[0021] Figure 4 Schematic diagram of the main structure of the needle valve in an embodiment of the present invention;

[0022] Figure 5 is a cross-sectional view of a metal heat-conducting sleeve according to an embodiment of the present invention;

[0023] Figure 6 is a cross-sectional view of a gas injector installed in an engine cylinder head according to an embodiment of the present invention;

[0024] Figure 7 Schematic diagram of the heat transfer process of a gas injector according to an embodiment of the present invention;

[0025] Figure 8 is a cross-sectional view of a gas injector according to another embodiment of the present invention;

[0026] Figure 9 This is a cross-sectional view of a gas injector installed in an engine cylinder head in another embodiment of the present invention.

[0027] In the picture:

[0028] 1. Metal thermal sleeve; 11. Positioning surface; 111. First sleeve; 112. Second sleeve; 113. Third sleeve; 1131. First section; 1132. Second section;

[0029] 2. Needle valve body; 21. Positioning step; 22. Material reduction groove; 23. First column; 231. First limiting surface; 24. Second column; 241. Second limiting surface; 25. Third column;

[0030] 3. Injector body;

[0031] 4. Tight cap;

[0032] 5. First seal;

[0033] 6. Second sealing member;

[0034] 7. Metal gasket;

[0035] 8. Engine cylinder head;

[0036] 91. Limiting step; 92. Inner cylindrical surface; 93. Outer cylindrical surface; 94. Heat transfer fluid. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0039] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0040] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0041] like Figures 1 to 9 As shown, this embodiment provides a gas injector, which includes a metal heat-conducting sleeve 1, the metal heat-conducting sleeve 1 having a positioning surface 11 in the cavity, the metal heat-conducting sleeve 1 can be installed in the engine cylinder head 8, and exchange heat with the cooling water in the engine cylinder head 8; a needle valve body 2, having a positioning step 21, the needle valve body 2 is inserted into the cavity of the metal heat-conducting sleeve 1, and the positioning step 21 abuts against the positioning surface 11; a heat transfer fluid 94 is arranged between the inner wall of the cavity of the metal heat-conducting sleeve 1 and the outer wall of the needle valve body 2, and the heat transfer fluid 94 can transfer the heat of the needle valve body 2 to the metal heat-conducting sleeve 1. The needle valve body 2 is inserted into the cavity of the metal heat-conducting sleeve 1, and the positioning step 21 abuts the positioning surface 11. This allows the needle valve body 2 to directly contact the metal heat-conducting sleeve 1, achieving the purpose of directly transferring heat from the needle valve body 2 to the metal heat-conducting sleeve 1, thereby improving the cooling effect of the needle valve body 2. At the same time, a heat transfer fluid 94 is arranged between the inner wall of the metal heat-conducting sleeve 1 cavity and the outer wall of the needle valve body 2. This arrangement allows the heat of the needle valve body 2 to be quickly transferred to the metal heat-conducting sleeve 1 by the heat transfer fluid 94. Compared with heat transfer through air, this method further improves the cooling effect of the needle valve body 2. Using the gas injector of the present invention, the heat of the needle valve body 2 can be quickly transferred to the metal heat-conducting sleeve 1 and the heat transfer fluid 94. The heat transfer fluid 94 ultimately transfers the heat to the metal heat-conducting sleeve 1. The metal heat-conducting sleeve 1 then transfers the heat to the cooling water in the engine cylinder head 8, removing the heat from the engine, thereby ensuring a relatively stable operating temperature of the needle valve body 2, extending its service life, and reducing replacement costs.

[0042] Optionally, in this embodiment, the metal heat-conducting sleeve 1 is made of copper, which has good thermal conductivity.

[0043] Specifically, the heat transfer fluid 94 can be configured as a paste-like lubricating grease or vaseline, which can improve the heat transfer effect between the needle valve body 2 and the metal heat-conducting sleeve 1 .

[0044] The specific operation process is as follows: When installing the injector body 3 onto the engine cylinder head 8, apply a paste of grease or vaseline to the outside of the injector body 3. After the outer surface of the injector body 3 and the needle valve body 2 are fully coated with the grease or vaseline, the injector body 3 is installed. After the engine is started and the injector body 3 is heated, the grease or vaseline on the outside of the injector body 3 melts into a liquid state. Under the action of gravity, the liquid grease or vaseline fills the gap between the needle valve body 2 and the metal heat-conducting sleeve 1, replacing air with the liquid grease or vaseline for heat conduction. Heat is quickly transferred from the needle valve body 2 to the wall of the metal heat-conducting sleeve 1, and then from the wall of the metal heat-conducting sleeve 1 to the cooling water, thereby cooling the needle valve body 2.

[0045] Alternatively, the gap between the needle valve body 2 and the metal heat-conducting sleeve 1 may be directly filled with engine oil, and the heat of the needle valve body 2 may be transferred to the metal heat-conducting sleeve 1 using the engine oil.

[0046] In this embodiment, if Figure 1 and Figure 2 As shown, the outer wall of the needle valve body 2 has a material reduction groove 22. This arrangement reduces the wall thickness of the needle valve body 2 while maintaining its structural strength, thereby improving its thermal conductivity. The material reduction groove 22 extends axially along the needle valve body 2 to accommodate some melted grease or petroleum jelly, further enhancing thermal conductivity.

[0047] Furthermore, there are a plurality of material reducing grooves 22, which are spaced apart along the circumference of the needle valve body 2. This arrangement further improves the heat conduction effect of the needle valve body 2.

[0048] Alternatively, under the premise of ensuring the structural strength of the needle valve body 2 , the wall thickness of the needle valve body 2 can be directly reduced to improve its heat conduction effect.

[0049] Specifically, if Figures 1 to 4 As shown, the needle valve body 2 includes a first cylinder 23, a second cylinder 24, and a third cylinder 25 connected in sequence. The diameter of the first cylinder 23 is larger than that of the second cylinder 24, and the diameter of the second cylinder 24 is larger than that of the third cylinder 25. This arrangement allows a positioning step 21 to be formed between the second cylinder 24 and the third cylinder 25. The outer wall of the second cylinder 24 has a material reduction groove 22.

[0050] Optionally, the needle valve body 2 may be made of stainless steel, heat-resistant die steel or the like, and may be machined as a whole or welded in sections.

[0051] The inner wall of the first column 23 has a first limiting surface 231, and the inner wall of the second column 24 has a second limiting surface 241. In this way, both the first limiting surface 231 and the second limiting surface 241 can be limitedly matched with the needle valve spring of the gas injector.

[0052] In this embodiment, if Figure 1 、 Figure 4 and Figure 5 As shown, the metal heat-conducting sleeve 1 includes a first sleeve 111, a second sleeve 112, and a third sleeve 113, which are connected in sequence. The diameter of the first sleeve 111 is larger than that of the second sleeve 112, which in turn is larger than that of the third sleeve 113. The third sleeve 113 has a positioning surface 11 therein, and the third sleeve 113 is provided so as to be mounted on the engine cylinder head 8. The second and third cylinders 24, 25 are inserted into the third sleeve 113, and the gap between the second and third cylinders 24, 113 can be set to 0.01 mm to 5 mm. This minimizes the gap between the second cylinder 24 of the needle valve body 2 and the third sleeve 113 of the metal heat-conducting sleeve 1. Among them, the gap between the second column 24 and the third sleeve 113 can be selected as 0.01mm, 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm or 0.5mm according to actual needs.

[0053] Furthermore, the third sleeve 113 includes a first section 1131 and a second section 1132 connected to each other. The inner diameter of the first section 1131 is larger than the inner diameter of the second section 1132, thereby forming a positioning surface 11;

[0054] In addition, an external thread is provided on the outer wall of the second section 1132, and the mounting hole of the engine cylinder head 8 has an internal thread. The metal heat-conducting sleeve 1 and the engine cylinder head 8 are connected by matching the external thread and the internal thread.

[0055] Optionally, the second section 1132 can determine the installation position of the needle valve body 2 and directly contact the high-temperature combustion gas in the engine.

[0056] Optionally, a limiting step 91 is provided on the outer wall of the second section 1132 , which can achieve thread limiting when installed on the engine cylinder head 8 .

[0057] Specifically, the gas injector further includes an injector body 3, a tight cap 4, a first seal 5, and a second seal 6. The tight cap 4 is disposed within the cavity of the metal heat-conducting sleeve 1, with a portion of the injector body 3 located within the cavity of the metal heat-conducting sleeve 1. The needle valve body 2 is connected to the injector body 3 via the tight cap 4. The first seal 5 is disposed between the outer wall of the needle valve body 2 and the inner wall of the injector body 3 to seal the gap between the needle valve body 2 and the injector body 3, preventing fluid from escaping the injector. The second seal 6 is disposed between the outer wall of the injector body 3 and the inner wall of the metal heat-conducting sleeve 1 to seal the gap between the injector body 3 and the metal heat-conducting sleeve 1, thereby isolating the engine oil from the engine cylinder head 8.

[0058] The first sealing member 5 and the second sealing member 6 are both sealing rings.

[0059] Optionally, the inner cylindrical surface 92 of the first sleeve 111 is in direct contact with the outside of the injector body 3, providing circumferential support to the injector body 3. This portion can cooperate with the second seal 6 of the injector body 3 so that the second seal 6 isolates the oil on the top surface of the cylinder head.

[0060] Optionally, there is a cylindrical surface at the top of the first sleeve 111, and the outer cylindrical surface 93 of the first sleeve 111 contacts the wall surface of the mounting hole of the injector body 3 on the engine cylinder head 8 to achieve circumferential positioning and seal cooling water and engine oil.

[0061] In this embodiment, if Figure 7 As shown, the gas injector further includes a metal gasket 7, which is disposed between the positioning step 21 and the positioning surface 11. The metal gasket 7 can transfer heat from the needle valve body 2 to the metal heat-conducting sleeve 1. The metal gasket 7 is made of copper, which has good thermal conductivity.

[0062] like Figure 8 and Figure 9 As shown, in another embodiment of the present invention, the injector body 3 may not be provided with Figure 1 The second seal 6 in the cylinder head 8 can be directly filled with the oil on the top surface of the engine cylinder head 8 to achieve heat conduction; similarly, the needle valve body 2 and the injector body 3 can also be directly welded without the tight cap 4 and the first seal 5.

[0063] Another embodiment of the present invention provides an engine comprising an engine cylinder head 8 and the gas injector of the above embodiment, wherein the metal heat-conducting sleeve 1 of the gas injector is mounted on the engine cylinder head 8. Using the engine of the present invention, heat from the needle valve body 2 can be rapidly transferred to the metal heat-conducting sleeve 1 and the heat transfer fluid 94. The heat transfer fluid 94 ultimately transfers the heat to the metal heat-conducting sleeve 1. The metal heat-conducting sleeve 1 then transfers the heat to the cooling water within the engine cylinder head 8, removing the heat from the engine. This ensures a relatively stable operating temperature for the needle valve body 2, extends its service life, reduces replacement costs, and thereby increases the service life of the engine.

[0064] The present invention operates as follows: During engine operation, the third column 25 of the needle valve body 2 receives heat from the high-temperature combustion chamber gases and gradually conducts it upward. Simultaneously, the second section 1132 of the metal heat-conducting sleeve 1 also receives heat and is heated. The needle valve body 2 and the metal heat-conducting sleeve 1, when heated, conduct heat axially toward the top. Once the heat reaches the second column 24 of the needle valve body 2, it begins to transfer to the liquid heat transfer fluid 94. Through molecular motion, the liquid heat transfer fluid 94 rapidly transfers the heat to the third sleeve 113. Because the metal heat-conducting sleeve 1 is made of metal, its high thermal conductivity allows it to quickly transfer heat to the outer wall of the sleeve 1. Since the outer wall of the sleeve 1 is in contact with the engine coolant, heat is quickly carried away by the coolant, preventing heat accumulation. Consequently, the wall temperature of the third sleeve 113 remains very low, ensuring rapid heat transfer. The positioning step 21 transfers the heat to the metal gasket 7, which in turn transfers the heat to the metal heat-conducting sleeve 1, where it is then transferred to the coolant through the outer wall of the sleeve 1.

[0065] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A gas injector, characterized in that: include: A metal heat-conducting sleeve (1), wherein a cavity of the metal heat-conducting sleeve (1) has a positioning surface (11), and the metal heat-conducting sleeve (1) can be installed on an engine cylinder head (8) and exchange heat with cooling water in the engine cylinder head (8); A needle valve body (2) having a positioning step (21), wherein the needle valve body (2) is inserted into the cavity of the metal heat-conducting sleeve (1), and the positioning step (21) abuts against the positioning surface (11); A heat transfer fluid (94) is provided between the inner wall of the cavity of the metal heat-conducting sleeve (1) and the outer wall of the needle valve body (2), and the heat transfer fluid (94) is capable of transferring heat from the needle valve body (2) to the metal heat-conducting sleeve (1); The outer wall of the needle valve body (2) has a material reduction groove (22), and the material reduction groove (22) extends along the axial direction of the needle valve body (2); There are a plurality of the material reducing grooves (22), and the plurality of the material reducing grooves (22) are arranged at intervals along the circumference of the needle valve body (2); The heat transfer fluid (94) is a paste-like lubricating grease or vaseline; The gas injector further comprises a metal gasket (7), which is arranged between the positioning step (21) and the positioning surface (11), and the metal gasket (7) is capable of transferring heat from the needle valve body (2) to the metal heat-conducting sleeve (1).

2. The gas injector according to claim 1, wherein The needle valve body (2) comprises a first cylinder (23), a second cylinder (24) and a third cylinder (25) connected in sequence, the diameter of the first cylinder (23) is larger than the diameter of the second cylinder (24), the diameter of the second cylinder (24) is larger than the diameter of the third cylinder (25), the positioning step (21) is formed between the second cylinder (24) and the third cylinder (25), and the outer wall of the second cylinder (24) has the material reduction groove (22).

3. The gas injector according to claim 2, wherein: The inner wall of the first column (23) has a first limiting surface (231), and the inner wall of the second column (24) has a second limiting surface (241). Both the first limiting surface (231) and the second limiting surface (241) can cooperate with the needle valve spring of the gas injector.

4. The gas injector according to claim 2, wherein: The metal heat-conducting sleeve (1) comprises a first sleeve (111), a second sleeve (112), and a third sleeve (113) connected in sequence, wherein the diameter of the first sleeve (111) is larger than the diameter of the second sleeve (112), the diameter of the second sleeve (112) is larger than the diameter of the third sleeve (113), the third sleeve (113) has the positioning surface (11), the second column (24) and the third column (25) are inserted into the third sleeve (113), the gap between the second column (24) and the third sleeve (113) is 0.01 mm to 5 mm, and the third sleeve (113) can be installed on an engine cylinder head (8).

5. The gas injector according to claim 4, wherein: The third sleeve (113) includes a first section (1131) and a second section (1132) connected to each other, the inner diameter of the first section (1131) is larger than the inner diameter of the second section (1132) to form the positioning surface (11), the outer wall of the second section (1132) has an external thread, and the mounting hole of the engine cylinder head (8) has an internal thread, and the external thread and the internal thread cooperate to connect the metal heat-conducting sleeve (1) and the engine cylinder head (8).

6. The gas injector according to any one of claims 1 to 5, characterized in that: The gas injector further comprises an injector body (3), a tight cap (4), a first sealing member (5) and a second sealing member (6), wherein the tight cap (4) is arranged in the cavity of the metal heat-conducting sleeve (1), a portion of the injector body (3) is located in the cavity of the metal heat-conducting sleeve (1), the needle valve body (2) is connected to the injector body (3) through the tight cap (4), the first sealing member (5) is arranged between the outer wall of the needle valve body (2) and the inner wall of the injector body (3), and is used to seal the gap between the needle valve body (2) and the injector body (3), and the second sealing member (6) is arranged between the outer wall of the injector body (3) and the inner wall of the metal heat-conducting sleeve (1), and is used to seal the gap between the injector body (3) and the metal heat-conducting sleeve (1).

7. An engine, characterized in that: The invention comprises an engine cylinder head (8) and a gas injector according to any one of claims 1 to 6, wherein the metal heat-conducting sleeve (1) of the gas injector is mounted on the engine cylinder head (8).

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