Piston, combustion chamber structure, and engine

Abstract

The application discloses a piston, a combustion chamber structure and an engine, wherein the top of the piston is provided with a pit and two convex structures, the pit is arranged between the two convex structures, and the outer periphery of the section of the pit perpendicular to the height direction of the piston is square. The technical scheme of the application aims to increase the tumble flow of the combustion chamber structure of the methanol engine, improve the combustion efficiency of the methanol engine, and simultaneously consider the compactness of the structure, the weight and the NVH performance.

Description

Technical Field

[0001] The present invention relates to the technical field of pistons, and in particular to a piston, a combustion chamber structure, and an engine. Background Art

[0002] In the current commercial vehicle engine market, methanol-fueled engines are typically developed based on traditional diesel platforms. However, because diesel engines utilize compression ignition and diffusion combustion, the cylinder head airflow is typically tangential or torsional vortex flow, and the cylinder head bottom surface is flat. Methanol engines, on the other hand, utilize ignition and premixed combustion, requiring a high tumble ratio to increase turbulent kinetic energy at the end of compression, accelerate flame propagation, and improve combustion efficiency. This requires parallel tumble flow in the cylinder head airflow, and the cylinder head bottom surface is designed as a ridge. These two engines have different requirements for combustion system structure design.

[0003] The volume of current engine combustion chambers is primarily concentrated in the piston head recess, which places certain constraints on the piston's structural design. Firstly, the combustion chamber structure, comprised of the cylinder head and piston, is not optimally suited to the requirements of spark-ignition methanol engines, resulting in low combustion efficiency. Secondly, the piston's high compression height makes the overall engine less compact and heavier. As a moving part, the piston's weight also leads to greater inertia, impacting both engine noise, harshness, and fuel efficiency.

[0004] Therefore, how to consider the piston as a whole, design a new high-tumble combustion system, improve the engine's combustion efficiency, and at the same time take into account structural compactness, weight, NVH, etc. is a problem that needs to be solved at present. Summary of the Invention

[0005] The main purpose of the present invention is to provide a piston that aims to increase the tumble flow of the combustion chamber structure of a methanol engine and improve the combustion efficiency of the methanol engine while taking into account the compactness of the structure, weight, and NVH performance.

[0006] To achieve the above objectives, the top of the piston proposed in the present invention is provided with a pit and two protruding structures, the pit is provided between the two protruding structures, and the outer periphery of the cross section of the pit perpendicular to the height direction of the piston is square.

[0007] Optionally, the outer periphery of the cross section has two opposite first edges, and one of the first edges is arranged in parallel with one of the protruding structures.

[0008] Optionally, a first edge is correspondingly provided on a protruding structure.

[0009] Optionally, the angle between the side of the protrusion close to the pit and the cross section is α, the angle between the side of the protrusion away from the pit and the cross section is β, and 30°≤α≤90°, 30°≤β≤90°.

[0010] More preferably, 42°≤α≤80°, 42°≤β≤80°.

[0011] More preferably, 45°≤α≤90°, and 45°≤β≤90°.

[0012] Optionally, α>β.

[0013] Optionally, the height of the protruding structure is s, where 1 mm ≤ s ≤ 10 mm.

[0014] More preferably, 4mm≤s≤8mm.

[0015] Optionally, a side of the protrusion structure close to the pit is arranged to have a smooth transition with a sidewall of the pit.

[0016] Optionally, any two adjacent sides of the outer periphery of the cross section are arranged in a smooth transition.

[0017] Optionally, the piston has a pin hole, and the two protruding structures are distributed along the depth direction of the pin hole.

[0018] Optionally, the depth of the pit ranges from greater than 0 mm to less than 35 mm.

[0019] Optionally, the ratio of the compression height of the piston to the maximum outer diameter of the piston is greater than 0.35 and less than 0.7.

[0020] More preferably, the depth of the pit is greater than 0 mm and less than 15 mm.

[0021] More preferably, the ratio of the compression height of the piston to the maximum outer diameter of the piston is greater than 0.35 and less than 0.65.

[0022] The present invention further provides a combustion chamber structure, comprising:

[0023] Cylinder liner;

[0024] a cylinder head, disposed on the cylinder liner; and

[0025] The piston is disposed in the cylinder liner, and the bottom of the cylinder head, the top of the piston, and the cylinder liner define a combustion chamber.

[0026] Optionally, the combustion chamber includes a piston combustion chamber provided in a recess of the piston, and a cylinder head combustion chamber provided at the bottom of the cylinder head, and the volume of the cylinder head combustion chamber is larger than the volume of the piston combustion chamber.

[0027] Optionally, the cylinder head combustion chamber has a first ridge surface and a second ridge surface connected at an angle, and a connection between the first ridge surface and the second ridge surface extends in a direction from one of the protruding structures to the other of the protruding structures.

[0028] More preferably, the combustion chamber structure further comprises an air intake valve provided on a first ridge surface, and an angle formed between the first ridge surface and the cross section is ε, wherein 15°≤ε≤45°.

[0029] More preferably, 20°≤ε≤30°.

[0030] Optionally, the combustion chamber structure further includes an exhaust valve provided on the second ridge surface, and the angle formed between the second ridge surface and the cross section is θ, wherein 15°≤θ≤45°.

[0031] More preferably, 20°≤θ≤30°.

[0032] The present invention further provides an engine, comprising:

[0033] engine body; and

[0034] The aforementioned combustion chamber structure is provided in the engine body.

[0035] Optionally, the engine is configured as a methanol engine.

[0036] In the technical solution of the present invention, the top of the piston is provided with a recess and two raised structures, with the recess located between the two raised structures. The simultaneous provision of the recess and raised structures enables the combustion chamber structure to form a larger tumble flow. Furthermore, the outer periphery of the recess, perpendicular to the height direction of the piston, is square. The combination of the two raised structures and the recess of this shape enables the combustion chamber structure to form a larger tumble flow, while suppressing the movement of secondary airflow in the later stages, significantly improving the combustion efficiency of the methanol engine. It is worth mentioning that, compared to recesses with circular or elliptical outer peripheries, the square recess in this solution, in combination with the two raised structures, unexpectedly enables a larger tumble flow to be formed within the combustion chamber structure, and more significantly suppresses the interference of secondary airflow in the later stages, thereby achieving a better combustion efficiency for the methanol engine. Furthermore, thanks to the design of the piston structure, the recess can be set shallower, reducing the compression height, making the engine more compact in height, reducing weight, and also improving NVH performance, thereby taking into account combustion efficiency, structural compactness, and NVH performance. Furthermore, according to the results of CFD simulation analysis, the high tumble combustion system formed by this piston structure and the ridge-type cylinder head significantly improves combustion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention 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 invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0038] Figure 1 This is a schematic structural diagram of an embodiment of a piston of the present invention;

[0039] Figure 2 for Figure 1 Front view of the middle piston;

[0040] Figure 3 1 is a top view of the piston in FIG.

[0041] Figure 4 for Figure 3 AA section view of the middle piston;

[0042] Figure 5 for Figure 3 BB cutaway view of the middle piston;

[0043] Figure 6 This is a schematic structural diagram of an embodiment of a combustion chamber structure of the present invention;

[0044] Figure 7 for Figure 6 GG cross-sectional view of the combustion chamber structure.

[0045] Description of Figure Numbers:

[0046] Label name Label name 100 piston 600 First ridge surface 200 pits 700 Second roof ridge 300 Raised structure 800 intake valve 400 Pin hole 900 exhaust valve 500 cylinder head 910 Combustion chamber structure

[0047] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the 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.

[0049] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship and movement status of the various components under a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0050] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; it can mean mechanical connection or electrical connection; it can mean direct connection, indirect connection through an intermediate medium, or abutment; it can mean internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting 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 meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually 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 the present invention.

[0052] The present invention proposes a piston, which aims to increase the tumble flow of the combustion chamber structure of a methanol engine and improve the combustion efficiency of the methanol engine while taking into account the compactness of the structure, weight and NVH performance.

[0053] Reference Figures 1 to 7 In one embodiment of the present invention, the top of the piston 100 is provided with a recess 200 and two raised structures 300. The recess 200 is located between the two raised structures 300. The simultaneous provision of the recess 200 and raised structures 300 enables the combustion chamber structure 910 to form a larger tumble flow. Furthermore, the outer periphery of the recess 200, perpendicular to the height direction of the piston 100, is square. The combination of the two raised structures 300 and the recess 200 of this shape enables the combustion chamber structure 910 to form a larger tumble flow, while suppressing the movement of secondary airflow later on, significantly improving the combustion efficiency of the methanol engine. It is worth noting that, compared to recesses 200 with circular or elliptical outer peripheries, the square recess 200 and the two raised structures 300 in this embodiment unexpectedly create a larger tumble flow within the combustion chamber structure 910, more significantly suppressing interference with the movement of secondary airflow later on, and thus achieving even better combustion efficiency for the methanol engine. Furthermore, thanks to the design of the piston 100 structure, the dimple 200 can be shallower, reducing compression height. This results in a more compact engine height, reduced weight, and improved NVH performance, thus achieving a balance between combustion efficiency, structural compactness, and NVH. Furthermore, CFD simulation analysis results show that the high-tumble combustion system formed by the piston 100 structure and the ridge-shaped cylinder head 500 significantly improves combustion efficiency.

[0054] It should be noted that the square mentioned herein includes but is not limited to a square and a rectangle. The square also includes a shape close to a square, that is, the square allows the sides to have a certain curvature and / or the angles between the sides are rounded.

[0055] Optionally, in one embodiment, the outer periphery of the cross section has two opposing first edges, one first edge corresponding to a protrusion 300 and arranged in parallel. It will be appreciated that the outer periphery of the cross section also has two opposing second edges, one second edge connecting one end of the two first edges, and the other second edge connecting the other ends of the two first edges. Because the outer periphery of the cross section is square, the spacing between the two second edges remains constant or changes only slightly, which facilitates the formation of a larger tumble flow in the combustion chamber structure 910. Of course, in other embodiments, a diagonal line of the cross section extends from one protrusion 300 to another protrusion 300.

[0056] Optionally, in one embodiment, a first edge is provided corresponding to a protrusion 300. This allows the two protrusions 300 to be closer to the recess 200, facilitating the formation of a larger tumble flow within the combustion chamber. Of course, in other embodiments, the spacing between the first edge and the protrusion 300 is greater than 0.5 mm and less than 1.5 mm.

[0057] Optionally, in one embodiment, a protrusion structure 300 extends along a corresponding first edge. In this way, more airflow passing through the first edge flows through the protrusion structure 300, which is conducive to forming a larger tumble flow in the combustion chamber, further improving the combustion efficiency of the methanol engine.

[0058] Optionally, in one embodiment, the angle between the side of the protrusion 300 near the recess 200 and the cross section is α, and the angle between the side of the protrusion 300 away from the recess 200 and the cross section is β, with 30°≤α≤90° and 30°≤β≤90°. This facilitates the formation of tumble flow within the combustion chamber and improves the combustion efficiency of the methanol engine.

[0059] Alternatively, in one embodiment, preferably, 45°≤α≤80°, 45°≤β≤80°, and more preferably, 45°≤α≤80°, 45°≤β≤80°. This facilitates further promoting tumble flow formation within the combustion chamber and improving the combustion efficiency of the methanol engine. The value of α may be, but is not limited to, 45°, 50°, 55°, 60°, 65°, 70°, 75°, or 80°. The value of β may be, but is not limited to, 45°, 50°, 55°, 60°, 65°, 70°, 75°, or 80°.

[0060] Alternatively, in one embodiment, α>β. That is, the slope of the protrusion 300 closer to the recess 200 is steeper, while the slope of the protrusion 300 away from the recess 200 is gentler. This facilitates the formation of tumble flow within the combustion chamber structure 910 and improves the combustion efficiency of the methanol engine.

[0061] Optionally, in one embodiment, the height of the protrusion 300 is s, where 1 mm ≤ s ≤ 10 mm. This facilitates the formation of tumble flow within the combustion chamber structure 910 and improves the combustion efficiency of the methanol engine. It should be noted that s is the height difference between the highest point of the protrusion 300 and the periphery of the pit opening 200.

[0062] Alternatively, in one embodiment, 4 mm ≤ s ≤ 8 mm. This further promotes the formation of tumble flow within the combustion chamber structure 910 and improves the combustion efficiency of the methanol engine. The value of s may be, but is not limited to, 4 mm, 4.5 mm, 5 mm, 5.5 mm, or 6 mm.

[0063] Optionally, in one embodiment, the side of the protrusion structure 300 close to the pit 200 is smoothly transitioned to the sidewall of the pit 200. This can reduce the loss of tumble flow energy and help the combustion chamber structure 910 form a larger tumble flow.

[0064] Optionally, in one embodiment, any two adjacent edges of the outer periphery of the cross section are arranged in a smooth transition, so as to reduce the loss of tumble flow energy and facilitate the combustion chamber structure 910 to form a larger tumble flow.

[0065] Optionally, in one embodiment, the piston 100 has a pin hole 400, and the two protruding structures 300 are distributed along the axis of the pin hole 400. Of course, in other embodiments, the two protruding structures 300 are respectively arranged in parallel with the pin hole 400.

[0066] To save development costs, existing methanol engines are typically modified from diesel engines. However, the structure of these methanol engines is also constrained by the structural constraints of the base engine being modified, namely the diesel engine, resulting in a relatively high overall height. Specifically, the piston 100 of these methanol engines is relatively tall, which in turn increases the overall height of the methanol engine, making it less compact in height. Thanks to the structural design of the piston 100 of the present invention, the dimple 200 can be shallower, reducing the compression height, making the engine more compact in height, reducing weight, and improving NVH performance. Optionally, in one embodiment, the depth of the dimple 200 ranges from greater than 0 mm to less than 35 mm. More preferably, the depth of the dimple 200 ranges from greater than 0 mm to less than or equal to 20 mm. More preferably, the depth of the dimple 200 ranges from greater than 0 mm to less than or equal to 15 mm. Even more preferably, the depth of the dimple 200 ranges from greater than 1 mm to less than or equal to 14 mm. Furthermore, the relatively small depth of the recess 200 helps reduce the compression height of the piston 100, thereby reducing the overall height of a methanol engine using this piston 100 and making the methanol engine more compact in height. When the ratio of the compression height of the piston 100 to its maximum outer diameter is small, the compression height of the piston 100 is small relative to its maximum outer diameter, reducing the overall height of the methanol engine using this piston 100 and making the engine more compact in height. When this ratio is large, the compression height of the piston 100 is large relative to its maximum outer diameter, which helps improve the structural strength of the piston 100. Therefore, when this ratio is between 0.35 and 0.7, the piston 100 has both a small compression height, reducing the overall height of the methanol engine and making it more compact in height, and a high structural strength, which helps improve the service life of the piston 100. It's worth noting that the smaller compression height also allows for a smaller volume for the piston 100, which in turn reduces its weight and inertia during movement, thereby improving the NVH and fuel efficiency of the methanol engine. It can be appreciated that the piston 100 of this embodiment simultaneously achieves a more compact height structure for the methanol engine, provides greater structural strength for the piston 100, improves the combustion efficiency of the spark-ignition methanol engine, and improves the NVH and fuel efficiency of the methanol engine.

[0067] The depth of the recess 200 is indicated by h in the accompanying drawings, the compression height is indicated by H in the accompanying drawings, and the maximum outer diameter of the piston 100 is indicated by D in the accompanying drawings.

[0068] Optionally, in one embodiment, the depth of the pit 200 may be, but is not limited to, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, or 15 mm.

[0069] Preferably, in one embodiment, the ratio of the compression height of the piston 100 to the maximum outer diameter of the piston 100 is greater than 0.35 and less than 0.65. Similarly, when this ratio is greater than 0.35 and less than 0.65, the piston 100 has a smaller compression height, resulting in a smaller overall height of the methanol engine and a more compact height structure. It also provides the piston 100 with higher structural strength, which is beneficial for increasing the service life of the piston 100. Of course, in other embodiments, the ratio of the compression height of the piston 100 to the maximum outer diameter of the piston 100 is greater than 0.35 and less than 0.65.

[0070] Optionally, in one embodiment, the sidewalls of the recess 200 and the bottom wall of the recess 200 are smoothly transitioned. In this way, the resistance of the airflow through the recess 200 is small, and the combustion chamber structure 910 using the piston 100 can form a large tumble flow, thereby improving the combustion efficiency of the combustion chamber structure 910.

[0071] The present invention further provides a combustion chamber structure 910, comprising a cylinder liner, a cylinder head 500, and the aforementioned piston 100. The specific structure of the piston 100 is similar to that of the aforementioned embodiments. Since the present combustion chamber structure 910 utilizes all the technical solutions of all the aforementioned embodiments, it at least possesses all the beneficial effects brought about by the technical solutions of the aforementioned embodiments, and therefore will not be further elaborated here. Specifically, the cylinder head 500 is disposed within the cylinder liner, and the piston 100 is disposed within the cylinder liner. The bottom of the cylinder head 500, the top of the piston 100, and the cylinder liner define a combustion chamber.

[0072] Alternatively, in one embodiment, the combustion chamber includes a piston combustion chamber located in the recess 200 of the piston 100 and a cylinder head 500 combustion chamber located at the bottom of the cylinder head 500. The volume of the cylinder head 500 combustion chamber is larger than that of the piston combustion chamber. Thus, the cylinder head 500 combustion chamber is the primary combustion chamber, which facilitates the formation of tumble flow.

[0073] Optionally, in one embodiment, the combustion chamber of cylinder head 500 has a first ridge surface 600 and a second ridge surface 700 connected at an angle, with the junction of the first ridge surface 600 and the second ridge surface 700 extending along the depth direction of pin hole 400. This allows a combustible gas mixture, such as air and methanol, to form a large tumble flow under the compression of the first ridge surface 600 and the second ridge surface 700, resulting in a more uniform mixing of the air and methanol, thereby improving the combustion efficiency of an engine employing this combustion chamber structure 910. Of course, in other embodiments, the specific structure of the combustion chamber of cylinder head 500 can be designed based on actual needs.

[0074] Optionally, in one embodiment, the combustion chamber structure 910 further includes an intake valve 800 disposed on the first ridge surface 600 , with the first ridge surface 600 forming an angle ε with the cross section, where 15°≤ε≤45°. If ε is too small, the methanol engine's overall width is compact, the height is increased, and the tumble ratio is minimally improved. If ε is too large, the methanol engine's overall width increases, the height decreases, and the requirements for the methanol engine's valve seat layout are high. Therefore, when 15°≤ε≤45°, the methanol engine's overall width and height are more appropriate, reducing the requirements for the methanol engine's vehicle placement. Furthermore, the requirements for the methanol engine's valve seat layout are reduced, and the methanol engine has a larger tumble ratio.

[0075] Alternatively, in one embodiment, 20° ≤ ε ≤ 30°. This further reduces the overall width and height of the methanol engine, lowering vehicle placement requirements. Furthermore, this reduces valve seat design requirements for the methanol engine and allows the methanol engine to have a higher tumble ratio. The value of ε can be, but is not limited to, 20°, 22°, 25°, 27°, or 30°.

[0076] Optionally, in one embodiment, the combustion chamber structure 910 further includes an exhaust valve 900 disposed on the second ridge surface 700. The angle formed between the second ridge surface 700 and the cross section is θ, where 15°≤θ≤45°. If θ is too small, the overall width of the methanol engine is compact and the height is increased. If θ is too large, the overall width of the methanol engine is increased and the height is decreased. Therefore, when 15°≤θ≤45°, the overall width and height of the methanol engine are more appropriate, reducing the requirements for the methanol engine's placement on the vehicle.

[0077] Alternatively, in one embodiment, 20°≤θ≤30°. This further reduces the overall width and height of the methanol engine, thereby reducing vehicle placement requirements. The value of θ may be, but is not limited to, 20°, 22°, 25°, 27°, or 30°.

[0078] The present invention further provides an engine comprising an engine body and the aforementioned combustion chamber structure 910. The specific structure of the combustion chamber structure 910 is described with reference to the aforementioned embodiments. Since the present engine utilizes all of the technical solutions of all of the aforementioned embodiments, it at least possesses all of the beneficial effects brought about by the technical solutions of the aforementioned embodiments, and therefore, no further description is given herein. The combustion chamber structure 910 is disposed within the engine body.

[0079] Alternatively, in one embodiment, the engine is configured as a methanol engine, and further, the engine is configured as a spark-ignition methanol engine. Of course, in other embodiments, the engine can also be a natural gas engine, a gasoline generator, or a hydrogen engine.

[0080] The above are only optional embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A piston for use in a premixed combustion methanol engine, characterized in that: The top of the piston is provided with a recess and two raised structures, the recess is provided between the two raised structures, and the outer periphery of the cross section of the recess perpendicular to the height direction of the piston is square; The angle between the side of the protrusion close to the pit and the cross section is α, the angle between the side of the protrusion away from the pit and the cross section is β, 45°≤α≤80°, 45°≤β≤80°, α>β.

2. The piston according to claim 1, wherein The outer periphery of the cross section has two opposite first edges, and one of the first edges is arranged in parallel with one of the protruding structures.

3. The piston according to claim 2, wherein A first edge is correspondingly disposed on one of the protruding structures.

4. The piston according to claim 1, wherein The height of the protruding structure is s, where 1 mm ≤ s ≤ 10 mm.

5. The piston according to claim 4, wherein 4mm≤s≤8mm.

6. The piston according to claim 1, wherein The side of the protrusion structure close to the pit is smoothly transitioned to the sidewall of the pit; And / or, any two adjacent sides of the outer periphery of the cross section are arranged in a smooth transition; And / or, the piston has a pin hole, and the two protruding structures are distributed along the axial direction of the pin hole.

7. The piston according to any one of claims 1 to 6, characterized in that The depth of the pit is in the range of greater than 0 mm and less than 35 mm, and the ratio of the compression height of the piston to the maximum outer diameter of the piston is in the range of greater than 0.35 and less than 0.

7.

8. The piston according to claim 7, wherein The depth of the pit is greater than 0 mm and less than 15 mm; And / or, the ratio of the compression height of the piston to the maximum outer diameter of the piston is greater than 0.35 and less than 0.

65.

9. A combustion chamber structure, characterized in that: include: Cylinder liner; a cylinder head, disposed on the cylinder liner; and The piston according to any one of claims 1 to 8 is disposed in the cylinder liner, wherein the bottom of the cylinder head, the top of the piston, and the cylinder liner define a combustion chamber.

10. The combustion chamber structure according to claim 9, characterized in that: The combustion chamber includes a piston combustion chamber provided in a recess of the piston and a cylinder head combustion chamber provided at a bottom of the cylinder head. The volume of the cylinder head combustion chamber is larger than that of the piston combustion chamber.

11. The combustion chamber structure according to claim 10, characterized in that: The cylinder head combustion chamber has a first ridge surface and a second ridge surface connected at an angle, and a connection between the first ridge surface and the second ridge surface extends along a direction from one of the protruding structures to the other of the protruding structures.

12. The combustion chamber structure according to claim 11, characterized in that: The combustion chamber structure further includes an air intake valve provided on a first ridge surface, and an angle ε formed between the first ridge surface and the cross section is 15°≤ε≤45°.

13. The combustion chamber structure according to claim 12, wherein: 20°≤ε≤30°.

14. The combustion chamber structure according to claim 11, wherein: The combustion chamber structure further includes an exhaust valve provided on the second ridge surface, and the angle formed between the second ridge surface and the cross section is θ, wherein 15°≤θ≤45°.

15. The combustion chamber structure according to claim 14, characterized in that: 20°≤θ≤30°.

16. An engine, characterized in that: include: Engine body; as well as The combustion chamber structure according to any one of claims 9 to 15, provided in the engine body.

17. The engine according to claim 16, wherein The engine is configured as a methanol engine.

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