Engine combustion structure and engine

Abstract

The utility model relates to the technical field of vehicles, in particular to an engine combustion structure and an engine, the engine combustion structure comprises a piston, a cylinder body and a cylinder cover, the cylinder cover is connected with the cylinder body, the cylinder body is provided with a piston cavity, the piston is arranged in the piston cavity in a sliding mode, the top surface of the piston is provided with a pit, and a combustion chamber is formed between the pit and the cylinder cover. The cylinder cover is provided with an air inlet channel and an exhaust channel which are both communicated with the combustion chamber, the piston is provided with a piston ring installation groove and further provided with a cylindrical face and a guide face, the bottom end and the top end of the guide face are connected with the cylindrical face and the top face respectively in an included angle mode, and the bottom end of the cylindrical face is connected with the top wall of the piston ring installation groove. The distance between the top end of the guide face and the cavity wall of the piston cavity is large, flame propagation can be met, unburned mixed gas in a slit of a combustion chamber can be consumed, the distance between the bottom end of the guide face and the cavity wall of the piston cavity and the distance between the cylindrical face and the cavity wall of the piston cavity are small, flame propagation cannot be met, and influences on the performance of the piston ring can be avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicles, in particular to an engine combustion structure and an engine. Background Art

[0002] For a normally operating gaseous fuel engine, the combustion chamber slit (mainly the top land clearance formed between the piston and the cylinder block, generally extending downward from the piston top surface to the top piston ring) is one of the main sources of unburned hydrocarbons in the cylinder of a spark ignition engine. If the combustion chamber slit is smaller than the double-wall quenching layer thickness (the minimum clearance that allows gaseous fuel to be successfully ignited between two walls), the flame cannot propagate into the combustion chamber slit, and the piston in a high-temperature state may cause cylinder scoring with the cylinder block due to its expansion; if the slit gap width is increased to above the double-wall quenching layer thickness, the flame can propagate into the combustion chamber slit and burn the accumulated unburned mixture therein, so as to achieve the purpose of reducing unburned hydrocarbons in the cylinder. However, when the mixture in the slit burns, it will affect the performance of the top piston ring. Summary of the Utility Model

[0003] The purpose of the utility model is to provide an engine combustion structure and an engine, which can reduce the unburned mixture in the cylinder while avoiding affecting the performance of the top piston ring.

[0004] On the one hand, the utility model provides an engine combustion structure, which includes a piston, a cylinder block and a cylinder head. The cylinder head is connected to the cylinder block. The cylinder block is provided with a piston cavity, and the piston is slidably arranged in the piston cavity. A concave pit is arranged on the top surface of the piston, and a combustion chamber is formed between the concave pit and the cylinder head. The cylinder head is provided with an intake passage and an exhaust passage both communicating with the combustion chamber. The piston is provided with a piston ring installation groove. The piston also has a cylindrical surface and a guiding surface. The bottom end of the cylindrical surface is connected to the top wall of the piston ring installation groove. The top end of the guiding surface is connected to the top surface at an angle. The bottom end of the guiding surface is connected to the top end of the cylindrical surface at an angle. The distance between the top end of the guiding surface and the wall of the piston cavity is greater than a set distance. The distances between the bottom end of the guiding surface and the wall of the piston cavity and between the cylindrical surface and the wall of the piston cavity are equal and both less than the set distance. The set distance is the minimum distance for the flame to propagate between the piston and the piston cavity wall.

[0005] As a preferred technical solution of the engine combustion structure, the cylinder head has a canopy top structure, and the canopy top structure is a concave cone shape, and the combustion chamber is formed between the concave pit and the canopy top structure.

[0006] As a preferred technical solution of the engine combustion structure, the roof structure includes an intake-side squish surface, an exhaust-side squish surface, and two intake-exhaust intermediate squish surfaces, all of which face the top surface of the piston. The intake-side squish surface, one of the intake-exhaust intermediate squish surfaces, the exhaust-side squish surface, and the other intake-exhaust intermediate squish surface are arranged in sequence along the circumferential direction of the piston, and the areas of the intake-side squish surface and the exhaust-side squish surface are both larger than the area of the intake-exhaust intermediate squish surface.

[0007] As a preferred technical solution of the engine combustion structure, the guiding surface includes an intake section, an exhaust section, and two intake-exhaust intermediate sections. The intake section, one of the intake-exhaust intermediate sections, the exhaust section, and the other intake-exhaust intermediate section are arranged in sequence along the circumferential direction of the piston. The intake section faces the intake-side squish surface, the exhaust section faces the exhaust-side squish surface, the two intake-exhaust intermediate sections respectively face the two intake-exhaust intermediate squish surfaces, and the angles between the intake section and the cylindrical surface and between the exhaust section and the cylindrical surface are both smaller than the angles between the intake-exhaust intermediate sections and the cylindrical surface.

[0008] As a preferred technical solution of the engine combustion structure, the angle between the intake section and the cylindrical surface is between 15° and 25°; the angle between the exhaust section and the cylindrical surface is between 15° and 25°.

[0009] As a preferred technical solution of the engine combustion structure, the angle between the intake section and the cylindrical surface gradually decreases from both ends to the middle; the angle between the exhaust section and the cylindrical surface gradually decreases from both ends to the middle.

[0010] As a preferred technical solution of the engine combustion structure, the angle between the intake-exhaust intermediate section and the cylindrical surface is between 45° and 60°.

[0011] As a preferred technical solution of the engine combustion structure, the angle between the intake-exhaust intermediate section and the cylindrical surface gradually increases from both ends to the middle.

[0012] As a preferred technical solution of the engine combustion structure, along the axial direction of the piston, the distance between the guiding surface and the piston ring installation groove is not less than 4 mm.

[0013] On the other hand, the present utility model provides an engine, including the engine combustion structure in any of the above solutions. The engine further includes an intake valve provided in the intake passage and an exhaust valve provided in the exhaust passage.

[0014] The beneficial effects of the present utility model are:

[0015] The present utility model provides an engine combustion structure and an engine. The engine combustion structure includes a piston, a cylinder block, and a cylinder head. The cylinder head is connected to the cylinder block. The cylinder block is provided with a piston cavity, and the piston is slidably disposed in the piston cavity. A concave pit is provided on the top surface of the piston, and a combustion chamber is formed between the concave pit and the cylinder head. The cylinder head is provided with an intake passage and an exhaust passage that are both communicated with the combustion chamber. The piston is provided with a piston ring installation groove. The piston also has a cylindrical surface and a guiding surface. The bottom end of the cylindrical surface is connected to the top wall of the piston ring installation groove. The top end of the guiding surface is connected to the top surface at an angle. The bottom end of the guiding surface is connected to the top end of the cylindrical surface at an angle. The distance between the top end of the guiding surface and the wall of the piston cavity is greater than a set distance. The distance between the bottom end of the guiding surface and the wall of the piston cavity and the distance between the cylindrical surface and the wall of the piston cavity are equal and both less than the set distance. The set distance is the minimum distance at which a flame can propagate between the piston and the wall of the piston cavity. When the mixture in the combustion chamber burns, the flame can enter the combustion chamber slit under the guidance of the guiding surface and burn the mixture, but the flame cannot propagate to between the cylindrical surface and the wall of the piston cavity, thereby avoiding affecting the performance of the piston ring below. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of the engine combustion structure in an embodiment of the present utility model;

[0017] Figure 2 is a partially enlarged view of the engine combustion structure in an embodiment of the present utility model Figure 1 ;

[0018] Figure 3 is a partially enlarged view of the engine combustion structure in an embodiment of the present utility model Figure 2 ;

[0019] Figure 4 is a schematic structural diagram of the cylinder head in an embodiment of the present utility model;

[0020] Figure 5 is a schematic structural diagram of the piston in an embodiment of the present utility model.

[0021] In the figure:

[0022] 1, piston; 11, top surface; 12, concave pit; 13, cylindrical surface; 14, guiding surface; 141, intake section; 142, exhaust section; 143, intake and exhaust intermediate section; 15, piston ring installation groove;

[0023] 2, cylinder block;

[0024] 3, cylinder head; 31, intake passage; 32, exhaust passage; 33, canopy top structure; 331, intake side squish surface; 332, exhaust side squish surface; 333, intake and exhaust intermediate squish surface;

[0025] 4. Combustion chamber;

[0026] 5. Intake valve;

[0027] 6. Exhaust valve;

[0028] 7. Spark plug. Detailed implementation manners

[0029] The technical solutions of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0030] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed 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", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0031] In the description of the present utility model, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0032] The embodiments of the present utility model will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present utility model and should not be construed as a limitation of the present utility model.

[0033] This embodiment provides an engine combustion structure for burning gaseous fuel.

[0034] Specifically, as Figures 1 to 3 shown, the engine combustion structure includes a piston 1, a cylinder block 2, and a cylinder head 3. The cylinder head 3 is connected to the cylinder block 2. The cylinder block 2 is provided with a piston cavity, and the piston 1 is slidably disposed in the piston cavity. A concave pit 12 is provided on the top surface 11 of the piston 1. A combustion chamber 4 is formed between the concave pit 12 and the cylinder head 3. The cylinder head 3 is provided with an intake passage 31 and an exhaust passage 32 both communicating with the combustion chamber 4. The piston 1 is provided with a piston ring groove 15. Wherein, a part of the piston 1 between the piston ring groove 15 and the top surface 11 of the piston 1 forms a combustion chamber slit with the wall of the piston cavity. The air entering from the intake passage 31 and the fuel injected into the combustion chamber 4 are mixed to form a mixture, and part of the mixture will enter the combustion chamber slit.

[0035] If the combustion chamber slit is smaller than the double-wall quenching layer thickness, the flame cannot propagate into the slit gap, and the piston 1 in a high-temperature state may cause a cylinder scoring phenomenon with the cylinder block 2 due to its expansion. Specifically, when the combustion chamber slit is smaller than the double-wall quenching layer thickness, if the mixture in the combustion chamber slit burns, the heat generated by the combustion will be transferred away by the cylinder block 2 and the piston 1, and the heat released by the combustion is less than the heat transferred away, resulting in the flame going out. Therefore, the flame cannot propagate in the combustion chamber slit. If the gap width of the combustion chamber slit is increased to be greater than the double-wall quenching layer thickness, the flame can propagate into the combustion chamber slit and burn the accumulated mixture therein, thereby achieving the purpose of reducing unburned hydrocarbons in the cylinder. However, when the mixture in the slit burns, it will affect the performance of the top piston ring.

[0036] In view of this, in this embodiment, the piston 1 further has a cylindrical surface 13 and a guiding surface 14. The bottom end of the cylindrical surface 13 is connected to the top wall of the piston ring groove 15. The top end of the guiding surface 14 is connected to the top surface 11 at an angle. The bottom end of the guiding surface 14 is connected to the top end of the cylindrical surface 13 at an angle. The distance between the top end of the guiding surface 14 and the wall of the piston cavity is greater than a set distance. The distance between the bottom end of the guiding surface 14 and the wall of the piston cavity and the distance between the cylindrical surface 13 and the wall of the piston cavity are equal and both less than the set distance. The set distance is the minimum distance at which the flame can propagate between the piston 1 and the piston cavity wall, that is, the set distance is equal to the double-wall quenching layer thickness. Specifically, please refer to Figure 1 , the distance between the bottom end of the guiding surface 14 and the wall of the piston cavity and the distance between the cylindrical surface 13 and the wall of the piston cavity are both L 1 , the distance between the top end of the guiding surface 14 and the wall of the piston cavity is L 2 , the double-wall quenching layer thickness is L, L 1 <L; L 2> L. With such a setting, when the air-fuel mixture in the combustion chamber 4 burns, the flame can enter the combustion chamber slit under the guidance of the guiding surface 14 and burn most of the air-fuel mixture therein; at the same time, the flame cannot spread between the cylindrical surface 13 and the wall of the piston cavity, thereby avoiding affecting the performance of the piston ring below.

[0037] Among them, in this embodiment, along the axial direction of the piston 1, the distance between the guiding surface 14 and the piston ring installation groove 15 is not less than 4 mm. With such a setting, it can fully avoid the influence of the combustion of the air-fuel mixture in the combustion chamber slit on the performance of the piston ring. In other embodiments, the distance between the guiding surface 14 and the piston ring installation groove 15 can also be set according to actual needs.

[0038] Optionally, please refer to Figure 1 , the cylinder head 3 has a canopy top structure 33, and the canopy top structure 33 is in the shape of an inwardly concave cone. A combustion chamber 4 is formed between the concave pit 12 and the canopy top structure 33. By adopting the canopy top structure, the air flow organization in the cylinder can be in the form of tumble flow. Among them, the canopy top structure is a prior art and is disclosed in prior patents with application numbers CN202310927401.0 and CN202310668256.9.

[0039] Optionally, please refer to Figure 4 , the canopy top structure 33 includes an intake side squish surface 331, an exhaust side squish surface 332, and two intake-exhaust intermediate squish surfaces 333 that are all opposite to the top surface 11 of the piston 1. The intake side squish surface 331, one intake-exhaust intermediate squish surface 333, the exhaust side squish surface 332, and the other intake-exhaust intermediate squish surface 333 are arranged in sequence along the circumferential direction of the piston 1, and the areas of the intake side squish surface 331 and the exhaust side squish surface 332 are both larger than the area of the intake-exhaust intermediate squish surface 333. Specifically, in this embodiment, the cylinder head 3 is provided with two intake channels 31 and two exhaust channels 32. The two intake channels 31 and the two exhaust channels 32 are evenly spaced along the axis of the piston 1, and the two intake channels 31 are adjacent to each other, and the two exhaust channels 32 are adjacent to each other. The intake side squish surface 331 is located between the two intake channels 31, the exhaust side squish surface 332 is located between the two exhaust channels 32, one intake-exhaust intermediate squish surface 333 is located between one intake channel 31 and one exhaust channel 32, and the other intake-exhaust intermediate squish surface 333 is located between the other intake channel 31 and the other exhaust channel 32. With such a setting, the air organization in the cylinder can be in the form of tumble flow.

[0040] Since the area of the intake and exhaust intermediate squish surface 333 is small, while the areas of the intake-side squish surface 331 and the exhaust-side squish surface 332 are large, thus, when the piston 1 moves downward, the reverse squish of the intake and exhaust intermediate squish surface 333 is weak, resulting in difficulty in sucking out the mixture gas in the part of the combustion chamber slit corresponding to the intake and exhaust intermediate squish surface 333. Therefore, the mixture gas in the part of the combustion chamber slit corresponding to the intake and exhaust intermediate squish surface 333 is relatively less, while the mixture gas in the parts of the combustion chamber slit corresponding to the intake-side squish surface 331 and the exhaust-side squish surface 332 is relatively more.

[0041] For this, please refer to Figure 5 , in this embodiment, the guiding surface 14 includes an intake section 141, an exhaust section 142, and two intake and exhaust intermediate sections 143. The intake section 141, one intake and exhaust intermediate section 143, the exhaust section 142, and the other intake and exhaust intermediate section 143 are arranged in sequence along the circumferential direction of the piston 1. Moreover, the intake section 141 faces the intake-side squish surface 331, the exhaust section 142 faces the exhaust-side squish surface 332, the two intake and exhaust intermediate sections 143 respectively face the two intake and exhaust intermediate squish surfaces 333, and the angles between the intake section 141 and the cylindrical surface 13 and between the exhaust section 142 and the cylindrical surface 13 are both smaller than the angle between the intake and exhaust intermediate section 143 and the cylindrical surface 13. With such a setting, smaller chamfers are formed between the intake section 141, the exhaust section 142 and the top surface 11 of the piston 1. The intake section 141 and the exhaust section 142 occupy a smaller area of the top surface 11, so that the parts of the top surface 11 corresponding to the intake section 141 and the exhaust section 142 have a larger area to cooperate with the intake-side squish surface 331 and the exhaust-side squish surface 332 to form reverse squish; while the area of the intake and exhaust intermediate squish surface 333 is relatively small and it is difficult to form reverse squish, but a larger chamfer is formed between the intake and exhaust intermediate section 143 and the top surface 11 of the piston 1. The intake and exhaust intermediate section 143 occupies a larger area of the top surface 11, so that the distance between the top of the intake and exhaust intermediate section 143 and the wall of the piston cavity is relatively large, and the propagation speed of the flame in the part of the combustion chamber slit corresponding to the intake and exhaust intermediate section 143 is more sufficient to fully reduce the mixture gas in the part of the combustion chamber slit corresponding to the intake and exhaust intermediate section 143.

[0042] Optionally, please refer to Figure 2 , the angle between the intake section 141 and the cylindrical surface 13 gradually decreases from both ends to the middle; the angle between the exhaust section 142 and the cylindrical surface 13 gradually decreases from both ends to the middle. With such a setting, both the intake section 141 and the exhaust section 142 can smoothly transition with the adjacent intake and exhaust intermediate sections 143. Preferably, the intake section 141 and the exhaust section 142 have the same structure and are arranged oppositely.

[0043] Optionally, please refer to Figure 3, the angle between the intake and exhaust section 143 and the cylindrical surface 13 gradually increases from both ends towards the middle.

[0044] Specifically, in this embodiment, the angle between the intake section 141 and the cylindrical surface 13 is α, and α is between 15° and 25°. For example, α can be 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24° or 25°.

[0045] In this embodiment, the angle between the exhaust section 142 and the cylindrical surface 13 is also between 15° and 25°. For example, the angle can be 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24° or 25°.

[0046] Please refer to Figure 3 , the angle between the intake and exhaust section 143 and the cylindrical surface 13 is β, and β is between 45° and 60°. For example, β can be 45°, 46°, 47°, 48°, 49°, 50°, 51°, 52°, 53°, 54°, 55°, 56°, 57°, 58°, 59° or 60°.

[0047] This embodiment also provides an engine, which includes the above engine combustion structure. The engine further includes an intake valve 5 disposed in the intake passage 31 and an exhaust valve 6 disposed in the exhaust passage 32.

[0048] Optionally, please refer to Figure 1 , the engine includes a spark plug 7 disposed in the cylinder head 3. The spark plug 7 is located in the combustion chamber 4 and is used to ignite the air-fuel mixture.

[0049] Optionally, the engine includes a plurality of pistons 1. The cylinder block 2 is provided with piston cavities corresponding to each piston 1, and a plurality of combustion chambers 4 are formed between the cylinder head 3 and the pits 12 of the plurality of pistons 1.

[0050] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An engine combustion structure, comprising a piston (1), a cylinder body (2) and a cylinder head (3), wherein the cylinder head (3) is connected to the cylinder body (2), the cylinder body (2) is provided with a piston cavity, the piston (1) is slidably arranged in the piston cavity, the top surface (11) of the piston (1) is provided with a pit (12), a combustion chamber (4) is formed between the pit (12) and the cylinder head (3), the cylinder head (3) is provided with an intake channel (31) and an exhaust channel (32) both of which are connected to the combustion chamber (4), the piston (1) is provided with a piston ring mounting groove (15), and is characterized in that: The piston (1) further comprises a cylindrical surface (13) and a guide surface (14); the bottom end of the cylindrical surface (13) is connected to the top wall of the piston ring mounting groove (15); the top end of the guide surface (14) is connected to the top surface (11) at an angle; the bottom end of the guide surface (14) is connected to the top end of the cylindrical surface (13) at an angle; the distance between the top end of the guide surface (14) and the cavity wall of the piston cavity is greater than a set distance; the distance between the bottom end of the guide surface (14) and the cavity wall of the piston cavity is equal to the distance between the cylindrical surface (13) and the cavity wall of the piston cavity and both are smaller than the set distance; the set distance is the minimum distance at which a flame can propagate between the piston (1) and the piston cavity wall.

2. The engine combustion structure according to claim 1, characterized in that: The cylinder head (3) has a roof structure (33) which is in the shape of an inwardly concave cone, and the combustion chamber (4) is formed between the recess (12) and the roof structure (33).

3. The engine combustion structure according to claim 2, characterized in that: The roof structure (33) comprises an intake side squeeze surface (331), an exhaust side squeeze surface (332) and two intake and exhaust squeeze surfaces (333), all of which are opposite to the top surface (11) of the piston (1); the intake side squeeze surface (331), one intake and exhaust squeeze surface (333), the exhaust side squeeze surface (332) and another intake and exhaust squeeze surface (333) are arranged in sequence along the circumferential direction of the piston (1); and the areas of the intake side squeeze surface (331) and the exhaust side squeeze surface (332) are both larger than the area of ​​the intake and exhaust squeeze surface (333).

4. The engine combustion structure according to claim 3, characterized in that: The guide surface (14) comprises an intake segment (141), an exhaust segment (142) and two intake and exhaust inter-segments (143); the intake segment (141), one intake and exhaust inter-segment (143), the exhaust segment (142) and another intake and exhaust inter-segment (143) are arranged in sequence along the circumferential direction of the piston (1); the intake segment (141) is opposite to the intake side squeeze surface (331); the exhaust segment (142) is opposite to the exhaust side squeeze surface (332); the two intake and exhaust inter-segments (143) are respectively opposite to the two intake and exhaust inter-segments (333); the angle between the intake segment (141) and the cylindrical surface (13) and the angle between the exhaust segment (142) and the cylindrical surface (13) are both smaller than the angle between the intake and exhaust inter-segment (143) and the cylindrical surface (13).

5. The engine combustion structure according to claim 4, characterized in that: The angle between the air intake segment (141) and the cylindrical surface (13) is between 15° and 25°; the angle between the air exhaust segment (142) and the cylindrical surface (13) is between 15° and 25°.

6. The engine combustion structure according to claim 5, characterized in that: The angle between the air intake segment (141) and the cylindrical surface (13) gradually decreases from both ends to the middle; and the angle between the air exhaust segment (142) and the cylindrical surface (13) gradually decreases from both ends to the middle.

7. The engine combustion structure according to claim 4, characterized in that: The included angle between the intake and exhaust section (143) and the cylindrical surface (13) is between 45° and 60°.

8. The engine combustion structure according to claim 7, characterized in that: The angle between the intake and exhaust section (143) and the cylindrical surface (13) gradually increases from both ends to the middle.

9. The engine combustion structure according to any one of claims 1 to 8, characterized in that: Along the axial direction of the piston (1), the distance between the guide surface (14) and the piston ring mounting groove (15) is not less than 4 mm.

10. An engine, characterized in that: The engine combustion structure comprises the engine combustion structure according to any one of claims 1 to 9, wherein the engine further comprises an intake valve (5) arranged in the intake passage (31), and an exhaust valve (6) arranged in the exhaust passage (32).

Images