Cylinder head, methanol engine and vehicle

Abstract

A cylinder head, provided with an air intake channel (1). The air intake channel (1) comprises an air intake section (11) and an air guide section (12); in the air flowing direction, the cross section of the air intake section (11) is gradually reduced; and the air guide section (12) is connected to the air intake section (11), is in an arc shape and is used for guiding airflow to form tumble flow. The cross section of the air intake section (11) is gradually reduced, so as to compress air in the air intake channel. Also involved are a methanol engine and a vehicle.

Description

Cylinder heads, methanol engines and vehicles

[0001] This application claims priority to Chinese patent application No. 202311250529.4 filed on September 25, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of methanol engines, and in particular to a cylinder head, a methanol engine and a vehicle. Background Art

[0003] Current heavy-duty methanol engines are essentially modified and optimized based on traditional diesel engine platforms. These engines typically utilize direct injection, with a combustion chamber formed by a flat cylinder head and piston top surface, and a spiral intake manifold for compression ignition of the mixture. However, because methanol's properties are similar to gasoline, adopting the combustion chamber structure of a traditional heavy-duty engine results in a poorly matched combustion system, resulting in low combustion efficiency. Technical issues

[0004] The main purpose of this application is to propose a cylinder head, a methanol engine and a vehicle, aiming to solve the problem of low combustion efficiency caused by the mismatch between the intake structure and the combustion system of existing heavy-duty methanol engines. Technical Solutions

[0005] To achieve the above objectives, the present application proposes a cylinder head for a methanol engine, wherein the cylinder head has an intake duct, and the intake duct includes:

[0006] an air inlet section, wherein the cross section of the air inlet section is tapered in the direction of gas flow; and

[0007] The air guide section is connected to the air inlet section and is arranged in an arc shape to guide the air flow to form a tumble flow.

[0008] In one embodiment, the air intake section includes an air intake first section and an air intake tail section connected in sequence, and the inclination angle of the inner side wall of the air intake first section relative to the center line of the air intake first section is greater than the inclination angle of the inner side wall of the air intake tail section relative to the center line of the air intake tail section.

[0009] In one embodiment, the inclination angle of the inner side wall of the first air intake section relative to the center line of the first air intake section is α1, wherein 7.5°≤α1≤15°.

[0010] In one embodiment, the inclination angle of the inner side wall of the air intake tail section relative to the center line of the air intake tail section is α2, wherein 2.5°≤α2≤5°.

[0011] In an axial cross section along the cylinder head, a curvature radius of an upper side wall of the air guide section is greater than a curvature radius of a lower side wall of the air guide section.

[0012] In one embodiment, the curvature radius of the upper side wall of the air guide section is R1, wherein 40 mm ≤ R1 ≤ 60 mm.

[0013] In one embodiment, the curvature radius of the lower side wall of the air guide section is R2, wherein 10 mm ≤ R2 ≤ 30 mm.

[0014] In one embodiment, the air guide section forms a throat, and along the projection plane of the outlet of the air inlet duct, the maximum distance between the projected curve of the side wall of the air inlet duct at the throat and the center of the outlet of the air inlet duct is a, and the radius of the outlet of the air inlet duct is b, wherein 0.7≤(a / b)≤0.8.

[0015] In one embodiment, the air intake section and the air guide section are correspondingly arranged as an air intake group, two air intake groups are provided, and the air intake sections of the two air intake groups are at least partially connected.

[0016] In one embodiment, a connecting side wall is formed between the two air intake groups, and the connecting side wall includes two guide side wall sections arranged at an angle.

[0017] In one embodiment, the included angle between the two guide side wall segments is α3, wherein 45°≤α3≤75°.

[0018] In one embodiment, the connecting side wall further includes a transition side wall segment connecting the two guide side wall segments, and the transition side wall segment is arranged in an arc shape.

[0019] In one embodiment, the curvature radius of the transition sidewall section is R3, wherein 5 mm ≤ R3 ≤ 15 mm.

[0020] In one embodiment, the cylinder head includes an end surface for forming an upper wall of a combustion chamber, the end surface includes a first inclined surface and a second inclined surface set at an angle, the cylinder head is provided with an exhaust duct, the exhaust duct is set corresponding to the first inclined surface, and the intake duct is set corresponding to the second inclined surface.

[0021] In one embodiment, the included angle between the first inclined surface and the second inclined surface is α4, and 120°≤α4≤150°.

[0022] In one embodiment, the boundary edge between the first inclined surface and the second inclined surface is offset from the center line of the cylinder head and away from the exhaust passage.

[0023] A transition surface is connected between the first inclined surface and the second inclined surface, and the transition surface is arranged in an arc-shaped curved surface.

[0024] In one embodiment, the lower end surface of the cylinder head includes an annular surface outside the combustion chamber thereof, and the annular surface is inclined toward the upper end of the cylinder head along the direction from the periphery of the cylinder head toward the center thereof.

[0025] In one embodiment, the angle between the annular surface and the horizontal line is α5, wherein 3°≤α5≤8°.

[0026] The present application also provides a methanol engine, comprising the above-mentioned cylinder head.

[0027] In addition, the present application also provides a vehicle comprising the above-mentioned methanol engine. Beneficial effects

[0028] In the technical solution of the present application, the cross-section of the intake section is set to be tapered to compress the gas in the intake duct, which is beneficial to increasing the flow rate of the gas in the intake duct. At the same time, the air guide section is set to guide the airflow in the intake duct to form a tumble flow in the combustion chamber. In this way, by setting the intake section and the air guide section, the flow rate of the gas in the intake duct can be increased, which helps to increase the tumble flow intensity, and the gas can be guided to form a tumble flow, effectively improving the mixing quality of methanol spray and fresh air, and improving the turbulent kinetic energy of the mixed gas, thereby helping to improve the combustion efficiency of the engine and reduce the engine's knock and pre-ignition tendency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0030] FIG1 is a schematic cross-sectional view of a cylinder head according to an embodiment of the present invention;

[0031] FIG2 is a schematic side view of the air intake duct in FIG1 ;

[0032] FIG3 is a schematic diagram of the top view of the structure along the AA direction in FIG2;

[0033] FIG4 is a schematic diagram of the structure of the air intake duct from above in FIG1 ;

[0034] FIG5 is a partial cross-sectional structural schematic diagram of the cylinder head in FIG1 ;

[0035] FIG6 is a bottom view of the cylinder head in FIG1 .

[0036] Description of Figure Numbers:

[0037] Reference numerals: Reference numerals: 100 cylinder head 21 first inclined surface 1 intake duct 22 second inclined surface 11 intake section 23 transition surface 111 intake first section 24 guide surface 112 intake tail section 3 exhaust duct 12 guide section 4 intake seat ring 13 connecting side wall 5 exhaust seat ring 131 guide side wall section 6 annular surface 132 transition side wall section

[0038] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. Modes for Carrying Out the Invention

[0039] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0040] It should be noted that if directional indications are involved in the embodiments of the present application, such directional indications are only used to explain the relative positional relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0041] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0042] Current heavy-duty methanol engines are primarily modified and optimized from conventional diesel engine platforms. These engines typically utilize direct injection, with a combustion chamber formed by a flat cylinder head and piston top surface, and a spiral intake manifold for compression ignition of the mixture. However, because methanol's properties are similar to gasoline, adopting the combustion chamber structure of conventional heavy-duty engines results in a poorly matched combustion system, resulting in low combustion efficiency.

[0043] Based on this, the present application provides a cylinder head for a methanol engine, aiming to address the problem of low combustion efficiency caused by the mismatch between the intake structure and the combustion system of existing heavy-duty methanol engines. Figures 1 to 6 are schematic structural diagrams of an embodiment of the cylinder head provided by the present application.

[0044] Please refer to Figures 1 to 3. The cylinder head 100 has an air intake duct 1, which includes an air intake section 11 and an air guide section 12. In the flow direction of the gas, the cross-section of the air intake section 11 is tapered. The air guide section 12 is connected to the air intake section 11. The air guide section 12 is arranged in an arc shape to guide the airflow to form a tumble flow.

[0045] In the technical solution of the present application, the cross-section of the intake section 11 is set to be tapered to compress the gas in the intake duct 1, which is beneficial to increasing the flow rate of the gas in the intake duct 1. At the same time, the air guide section 12 is set to guide the airflow in the intake duct 1 to form a tumble flow in the combustion chamber. In this way, by setting the intake section 11 and the air guide section 12, the flow rate of the gas in the intake duct 1 can be increased, which helps to increase the tumble flow intensity, and the gas can be guided to form a tumble flow, effectively improving the mixing quality of methanol spray and fresh air, and improving the turbulent kinetic energy of the mixed gas, thereby helping to improve the combustion efficiency of the engine and reduce the engine's knock and pre-ignition tendency.

[0046] Further, referring to Figure 2, the intake section 11 includes an intake first section 111 and an intake tail section 112 connected in sequence, and the inclination angle of the inner side wall of the intake first section 111 relative to the center line of the intake first section 111 is greater than the inclination angle of the inner side wall of the intake tail section 112 relative to the center line of the intake tail section 112. In this way, the intake first section 111 adopts a large-angle tapered structure, which not only helps to expand the intake area of ​​the intake duct 1, but also helps to quickly increase the gas flow rate in the intake duct 1, while the intake tail section 112 adopts a small-angle tapered structure to reduce the gas flow rate of the gas in the intake duct 1 to prevent the gas flow rate in the intake duct 1 from changing too quickly, thereby helping to control the gas flow rate in the intake duct 1, which is beneficial to controlling the formation and maintenance of tumble flow.

[0047] In order to control the rate of change of the gas flow rate in the intake duct 1, in this embodiment, the inclination angle α1 of the inner sidewall of the first intake section 111 relative to the centerline of the first intake section 111 is 7.5°≤α1≤15°, so that the gas flow rate in the intake duct 1 can increase uniformly at a certain acceleration to prevent the gas flow rate from changing too quickly or too slowly. It is understood that the inclination angle α1 of the inner sidewall of the first intake section 111 relative to the centerline of the first intake section 111 can be 8°, 10°, 12°, or 13°, and of course can be any value within the above range, and this application is not limited to this.

[0048] In order to maintain the gas flow rate in the intake duct 1, in this embodiment, the inclination angle of the inner side wall of the intake tail section 112 relative to the centerline of the intake tail section 112 is α2, where 2.5°≤α2≤5°. Since the gas needs to overcome flow resistance during the flow process, the gas will experience pressure head loss. Therefore, 2.5°≤α2≤5° helps maintain the gas flow rate to prevent the gas flow rate from decreasing, so that the gas flow rate can be kept within a preset range, thereby helping to maintain the gas flow rate and flow coefficient. It is understandable that the inclination angle α2 of the inner side wall of the intake tail section 112 relative to the centerline of the intake tail section 112 can be 3°, 3.25°, 4°, or 4.5°, and of course it can be any value within the above range, and this application is not limited to this.

[0049] In order to guide the gas in the intake duct 1 to form a tumble flow, in this embodiment, please refer to Figure 2. On the axial cross-section along the cylinder head 100, the curvature radius of the upper side wall of the air guide section 12 is greater than the curvature radius of the lower side wall of the air guide section 12. In this way, the upper side wall of the air guide section 12 adopts a large curvature radius to reduce the flow resistance loss of the gas, which helps to improve the flow coefficient of the gas, thereby helping to maintain the tumble flow. At the same time, the lower side wall of the air guide section 12 adopts a small curvature radius to reduce the cross-section of the air guide section 12, which helps to improve the tumble flow intensity of the gas. Furthermore, in one embodiment, the curvature radius of the upper side wall of the air guide section 12 is R1, wherein 40mm≤R1≤60mm. Since the gas in the air inlet duct 1 is mainly guided by the upper side wall of the air guide section 12, if the curvature radius is too large, it is not conducive to the formation of tumble flow, and if the curvature radius is too small, it is not conducive to the maintenance of tumble flow. Therefore, 40mm≤R1≤60mm can both guide the gas to form tumble flow and facilitate the maintenance of tumble flow. In another embodiment, the curvature radius of the lower side wall of the air guide section 12 is R2, wherein 10mm≤R2≤30mm, so as to increase the tumble flow intensity of the gas. It is understandable that the curvature radius R1 of the upper side wall of the air guide section 12 can be 45mm, 50mm or 55mm, and of course it can also be any value in the above range, and this application does not limit this. Similarly, the curvature radius R2 of the lower side wall of the air guide section 12 can be 15 mm, 20 mm or 25 mm, and of course it can also be any value in the above range, which is not limited in this application.

[0050] In order to improve the tumble effect of the air intake duct 1, in this embodiment, please refer to Figures 2 and 3, the air guide section 12 forms a throat, and on the projection plane along the outlet of the air intake duct 1, the maximum distance between the projection curve of the side wall of the air intake duct 1 at the throat and the center of the outlet of the air intake duct 1 is a, and the radius of the outlet of the air intake duct 1 is b, wherein 0.7≤(a / b)≤0.8, so that the gas in the air intake duct 1 is as close as possible to the upper side wall of the air guide section 12, so that most of the gas can flow out from the upper half of the air guide section 12, thereby ensuring the tumble effect of the gas in the air intake duct 1.

[0051] In order to increase the air intake volume of the cylinder of the methanol engine, in this embodiment, the air intake section 11 and the air guide section 12 are correspondingly arranged as an air intake group, and two air intake groups are provided. The air intake sections 11 of the two air intake groups are at least partially connected. In this way, by providing two air intake groups, the air intake first section 111 can supply air to the two air intake groups, so that one air intake first section 111 can be shared. This can not only increase the air intake volume while streamlining the air supply structure of the methanol engine, but also enable the air intake duct 1 to avoid the bolts on the cylinder to prevent the air intake duct 1 from interfering with the bolts.

[0052] Furthermore, a connecting side wall 13 is formed between the two intake groups. The connecting side wall 13 includes two guide side wall sections 131 arranged at an angle. The angle between the two guide side wall sections 131 is α3, where 45°≤α3≤75°. If the angle between the two guide side wall sections 131 is too large, the gas flow rate will increase, causing greater disturbance to the gas in the intake duct 1. If the angle is too small, the difficulty of forming the intake duct 1 will increase. Therefore, 45°≤α3≤75° can reduce the impact of the connecting side wall 13 on the airflow and facilitate manufacturing and forming. It is understandable that the angle α3 between the two guide side wall sections 131 can be 50°, 60°, or 70°, and of course it can be any value within the above range. This is not limited in this application.

[0053] To facilitate the connection of the two guide sidewalls, in this embodiment, the connecting sidewall 13 also includes a transition sidewall section 132 connecting the two guide sidewall sections 131. The transition sidewall section 132 is arranged in an arc shape, and the curvature radius of the transition sidewall section 132 is R3, where 5mm≤R3≤15mm. In this way, the use of the arc-shaped transition sidewall section 132 allows the connecting sidewall 13 to transition smoothly, which helps to reduce stress concentration between the two transition sidewall sections 132. Of course, in other embodiments, the transition sidewall section 132 can also be arranged in a straight line, etc., and this application is not limited to this. It is understandable that the curvature radius R3 of the transition sidewall section 132 can be 7.5mm, 10mm, or 125mm, and of course it can also be any value within the above range, and this application is not limited to this.

[0054] Referring to Figures 1 and 5 , the cylinder head 100 includes an end surface that forms the upper wall of the combustion chamber. This end surface includes a first inclined surface 21 and a second inclined surface 22 arranged at an angle. The cylinder head 100 is provided with an exhaust duct 3, which is arranged corresponding to the first inclined surface 21, and an intake duct 1 is arranged corresponding to the second inclined surface 22. The angle between the first inclined surface 21 and the second inclined surface 22 is α4, with a range of 120°≤α4≤150°. This allows the end surface of the cylinder head 100 to conform to the intake duct 1, allowing the gas within the intake duct 1 to form a tumble flow within the combustion chamber. It is understood that the combustion chamber refers to the enclosed space formed by the cylinder head 100, the cylinder block, and the piston, which is used to combust methanol fuel. It is understood that the angle α4 between the first inclined surface 21 and the second inclined surface 22 can be 130°, 135°, or 145°, or any value within this range, and this is not limited in this application.

[0055] In order to guide the airflow out of the intake duct 1, in this embodiment, referring to FIG. 5 , the boundary edge of the first inclined surface 21 and the second inclined surface 22 is offset from the centerline of the cylinder head 100 along a side away from the exhaust duct 3, so that the first inclined surface 21 can guide the gas out of the intake duct 1, allowing the gas to flow along the first inclined surface 21 to form a tumble flow in the combustion chamber. Specifically, the offset distance L between the boundary edge of the first inclined surface 21 and the second inclined surface 22 and the centerline of the cylinder head 100 is, where 0 mm ≤ L ≤ 3 mm. It is understood that the offset distance L between the boundary edge of the first inclined surface 21 and the second inclined surface 22 and the centerline of the cylinder head 100 can be 1 mm, 2 mm, or 2.5 mm, and of course can be any value within the above range, which is not limited in this application.

[0056] In order to guide the gas flowing out of the air intake duct 1, a transition surface 23 is connected between the first inclined surface 21 and the second inclined surface 22. The transition surface 23 is set as an arc-shaped curved surface. In this way, by setting the transition surface 23, a smooth transition can be achieved between the second inclined surfaces 22 to avoid forming a gas gathering area between the first inclined surface 21 and the second inclined surface 22, so as to guide the gas flowing out of the air intake duct 1 to the first inclined surface 21, thereby helping the gas to form a tumble flow. Specifically, the curvature radius of the transition surface 23 is R4, where 15mm≤R4≤30mm. It can be understood that the curvature radius R4 of the transition surface 23 can be 18mm, 22.5mm or 27mm, and of course it can also be any value in the above range, and this application does not limit this.

[0057] In another embodiment, the cylinder head 100 includes an end surface for forming an upper wall of the combustion chamber. The end surface includes a guide surface 24 connecting the first inclined surface 21 on a side facing away from the second inclined surface 22. The guide surface 24 is configured as an arc-shaped curved surface, and the radius of curvature of the guide surface 24 is R5, where 8mm≤R5≤15mm. Thus, by providing the guide surface 24, gas flowing along the first inclined surface 21 is guided downward to form a tumble flow. It is understood that the radius of curvature R5 of the guide surface 24 can be 10mm, 12.5mm, or 14mm, or any value within the above range, and this application is not limited thereto.

[0058] Referring to Figures 5 and 6, the lower end surface of the cylinder head 100 includes an annular surface 6 located outside its combustion chamber. The annular surface 6 is inclined toward the upper end of the cylinder head 100 along the periphery of the cylinder head 100 toward its center. In this way, by providing the annular surface 6, the casting area of ​​the combustion chamber is reduced, thereby helping to reduce the casting deviation of the combustion chamber, which is beneficial to ensuring the consistency of combustion in each cylinder of the methanol engine. At the same time, the annular surface 6 is inclined to facilitate subsequent processing of the lower end surface of the cylinder head 100. Furthermore, the angle between the annular surface 6 and the horizontal line is α5, where 3°≤α5≤8°. It is understandable that the angle α5 between the annular surface 6 and the horizontal line can be 4°, 5.5°, or 6°, and of course it can be any value within the above range, and this application is not limited to this.

[0059] The present application also provides a methanol engine, including the aforementioned cylinder head 100. It should be noted that the structure of the cylinder head 100 in the methanol engine can refer to the aforementioned embodiments of the cylinder head 100 and will not be further described here. Since the aforementioned cylinder head 100 is used in the methanol engine provided by the present application, the embodiments of the methanol engine provided by the present application include all technical solutions of all the aforementioned embodiments of the cylinder head 100, and the technical effects achieved are also identical, which will not be further described here.

[0060] In addition, the present application also provides a vehicle, including the aforementioned vehicle. It should be noted that the structure of the methanol engine in the vehicle can refer to the aforementioned methanol engine embodiments, and will not be further described here. Since the aforementioned methanol engine is used in the vehicle provided by the present application, the embodiments of the vehicle provided by the present application include all technical solutions of all the aforementioned methanol engine embodiments, and the technical effects achieved are also identical, and will not be further described here.

[0061] The above description is merely an optional embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made based on the concept of the present application and the contents of the present application specification and drawings, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A cylinder head for a methanol engine, the cylinder head having an intake passage, wherein: The air inlet comprises: an air inlet section, wherein the cross section of the air inlet section is gradually reduced in the direction of gas flow; and The air guide section is connected to the air intake section and is arranged in an arc shape to guide the air flow to form a tumble flow.

2. The cylinder head according to claim 1, wherein: The air intake section includes an air intake first section and an air intake tail section connected in sequence, and the inclination angle of the inner side wall of the air intake first section relative to the center line of the air intake first section is greater than the inclination angle of the inner side wall of the air intake tail section relative to the center line of the air intake tail section.

3. The cylinder head according to claim 2, wherein: The inclination angle of the inner side wall of the first air intake section relative to the center line of the first air intake section is α1, wherein 7.5°≤α1≤15°.

4. The cylinder head according to claim 2 or 3, wherein: The inclination angle of the inner side wall of the air intake tail section relative to the center line of the air intake tail section is α2, wherein 2.5°≤α2≤5°.

5. The cylinder head according to claim 1, wherein: In an axial cross section along the cylinder head, a curvature radius of an upper side wall of the air guide section is greater than a curvature radius of a lower side wall of the air guide section.

6. The cylinder head according to claim 5, wherein: The curvature radius of the upper side wall of the air guide section is R1, wherein 40 mm ≤ R1 ≤ 60 mm.

7. The cylinder head according to claim 5 or 6, wherein: The curvature radius of the lower side wall of the air guide section is R2, wherein 10 mm ≤ R2 ≤ 30 mm.

8. The cylinder head according to claim 5, wherein: The air guide section forms a throat, and on the projection plane along the outlet of the air inlet duct, the maximum distance between the projection curve of the side wall of the air inlet duct at the throat and the center of the outlet of the air inlet duct is a, and the radius of the outlet of the air inlet duct is b, wherein 0.7≤(a / b)≤0.

8.

9. The cylinder head according to claim 1, wherein: The air intake section and the air guide section are correspondingly arranged as an air intake group, two air intake groups are arranged, and the air intake sections of the two air intake groups are at least partially connected.

10. The cylinder head according to claim 9, wherein: A connecting side wall is formed between the two air intake groups, and the connecting side wall includes two guide side wall sections arranged at an angle.

11. The cylinder head according to claim 10, wherein: The included angle between the two guide side wall sections is α3, wherein 45°≤α3≤75°.

12. The cylinder head according to claim 10, wherein: The connecting side wall also includes a transition side wall section connecting the two guide side wall sections, and the transition side wall section is arranged in an arc shape.

13. The cylinder head according to claim 12, wherein: The curvature radius of the transition side wall section is R3, wherein 5mm≤R3≤15mm.

14. The cylinder head according to claim 1, wherein: The cylinder head includes an end surface for forming an upper wall of a combustion chamber, the end surface includes a first inclined surface and a second inclined surface arranged at an angle, the cylinder head is provided with an exhaust passage, the exhaust passage is arranged corresponding to the first inclined surface, and the intake passage is arranged corresponding to the second inclined surface.

15. The cylinder head according to claim 14, wherein: An included angle between the first inclined surface and the second inclined surface is α4, and 120°≤α4≤150°.

16. The cylinder head according to claim 14, wherein: The boundary edge between the first inclined surface and the second inclined surface is offset along the center line of the cylinder cover and away from the exhaust passage.

17. The cylinder head according to any one of claims 14 to 16, wherein: A transition surface is connected between the first inclined surface and the second inclined surface, and the transition surface is arranged in an arc-shaped curved surface.

18. The cylinder head according to claim 1, wherein: The lower end surface of the cylinder head includes an annular surface outside the combustion chamber thereof, and the annular surface is inclined toward the upper end of the cylinder head along the direction from the periphery of the cylinder head toward the center thereof.

19. The cylinder head according to claim 18, wherein: The angle between the annular surface and the horizontal line is α5, wherein 3°≤α5≤8°.

20. A methanol engine, wherein: The methanol engine comprises the cylinder head according to any one of claims 1 to 19.

21. A vehicle, wherein: The vehicle includes the methanol engine as claimed in claim 20.

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