Engine

Abstract

The invention provides an engine which comprises an air cylinder, a piston and a cylinder cover, the piston is movably arranged in the air cylinder, and a protruding part gradually protruding inwards in the radial direction is formed on the top edge of the piston. The cylinder cover is installed on the cylinder, a combustion chamber is defined by the cylinder cover, the cylinder and the piston, a matching part surrounding the combustion chamber is formed on the surface, facing the combustion chamber, of the cylinder cover, and the protruding part is configured to respond to the piston to move upwards to the upper dead center to be in clearance fit with the matching part.

Description

Technical Field

[0001] The present disclosure relates to the technical field of engine structures, and more particularly, to an engine. Background Art

[0002] An engine is a thermal machine that converts the chemical energy of fuel into mechanical energy. It is widely used in the fields of automobiles, ships, aviation, etc. Its core working principle is to generate high-temperature and high-pressure gas by burning fuel, which drives the piston to move, and then drives the crankshaft to rotate and output power. According to the different working cycles, engines can be divided into four-stroke engines and two-stroke engines; according to the different ignition methods, they can be divided into spark-ignition engines (such as gasoline engines) and compression-ignition engines (such as diesel engines).

[0003] Compression ratio is a crucial parameter in engine design and performance optimization. Compression ratio refers to the ratio of the cylinder volume (total volume) when the piston is at the bottom dead center in the engine cylinder to the cylinder volume (combustion chamber volume) when the piston is at the top dead center. The compression ratio directly affects the thermal efficiency, power performance and emission characteristics of the engine. A higher compression ratio can improve the combustion efficiency of the fuel, increase the engine's output power, and reduce fuel consumption. However, too high a compression ratio may also cause knocking, especially in gasoline engines, which can damage engine components and reduce their reliability. Therefore, the design of the engine needs to find the best balance between compression ratio, fuel type, and combustion stability.

[0004] In the relevant technology, the compression ratio of gasoline engines is usually 10-12, and its thermal efficiency is about 36%. In order to further improve the thermal efficiency, the compression ratio needs to be increased to 15 or even higher. Under the premise that the engine displacement remains unchanged, increasing the compression ratio requires reducing the volume of the combustion chamber. However, in the entire combustion chamber, not all areas of the mixture can be fully burned. When the piston runs to the top dead center, the combustion flame cannot spread to the narrow gap area between the top of the piston and the cylinder head. This results in an increase in the proportion of the narrow gap area when the volume of the combustion chamber is reduced, and the overall combustion efficiency is not significantly improved, and the emission of pollutants increases. Therefore, how to provide an engine that can further improve the compression ratio while reducing the negative impact on combustion efficiency and emissions has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the present disclosure provides an engine that can effectively reduce the gap between the piston and the cylinder head when the piston is at the top dead center, reduce the incomplete phenomenon caused by the gap, and help the engine to further improve the compression ratio.

[0006] One aspect of the present disclosure provides an engine, comprising: a cylinder; a piston movably arranged in the cylinder, the top edge of the piston being formed with a raised portion that gradually rises inwardly along a radial direction; and a cylinder head mounted on the cylinder and defining a combustion chamber together with the cylinder and the piston; wherein a mating portion surrounding the combustion chamber is formed on a surface of the cylinder head facing the combustion chamber, and the raised portion is configured to form a clearance fit with the mating portion in response to the piston moving upward to a top dead center.

[0007] According to an embodiment of the present disclosure, the mating portion is configured to be gradually recessed inwardly along a radial direction from a surface edge of the cylinder head toward the combustion chamber to form a clearance fit with the protrusion of the protrusion.

[0008] According to an embodiment of the present disclosure, the mating space defined by the mating portion is configured as a truncated cone-shaped space.

[0009] According to an embodiment of the present disclosure, the cross-section of the truncated cone-shaped space is a trapezoid, and the angle between the two waists of the trapezoidal cross-section is an obtuse angle.

[0010] According to an embodiment of the present disclosure, two of the above-mentioned protrusions are formed and are spaced apart in the circumferential direction, and a flat top portion coplanar with the top portion of the above-mentioned piston is formed between the two above-mentioned protrusion portions.

[0011] According to an embodiment of the present disclosure, the two protrusions are arranged at both ends of the piston top in a radial direction.

[0012] According to an embodiment of the present disclosure, a pit is further formed at the center of the piston top, which is suitable for guiding the airflow in the combustion chamber to form a planar vortex.

[0013] According to an embodiment of the present disclosure, the surface roughness of the above-mentioned protruding portion and / or the surface roughness of the above-mentioned matching portion is less than or equal to Ra3.2.

[0014] According to an embodiment of the present disclosure, the spacing between the protruding portion and the matching portion when they form a clearance fit is d, and 0.5 mm ≤ d ≤ 1 mm.

[0015] The engine provided by the present disclosure provides a mating portion matching the raised portion on the top of the piston on the side of the cylinder head facing the combustion chamber, that is, on the bottom surface of the cylinder head, so that when the piston runs to the top dead center, the raised portion can form a clearance fit with the mating portion. The clearance fit effectively prevents or reduces incomplete combustion of the mixed gas while ensuring that the piston and the cylinder head do not collide. Therefore, when the compression ratio is increased while the engine displacement remains unchanged, the emission of pollutants is reduced and the combustion efficiency can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0017] Figure 1 is a cross-sectional schematic diagram of an engine provided by the present disclosure, showing a cylinder, a piston and a cylinder head;

[0018] Figure 2 yes Figure 1 A partial enlarged view of

[0019] Figure 3 yes Figure 1 In the exemplary embodiment shown, a schematic diagram of the surface of the cylinder head facing the combustion chamber is shown;

[0020] Figure 4 A simplified diagram of the engine structure provided by the present disclosure;

[0021] Figure 5 is a partial cross-sectional schematic diagram of an engine provided by the present disclosure;

[0022] Figure 6 yes Figure 1 In the exemplary embodiment shown, a perspective view of the head of the piston;

[0023] Figure 7 yes Figure 1 In the exemplary embodiment shown, a schematic plan view of a piston is provided.

[0024] In the drawings, the meanings of the reference numerals are as follows:

[0025] 1. Cylinder;

[0026] 2. Protect optical fiber;

[0027] 21. Raised part;

[0028] 22. Flat top;

[0029] 23. pits;

[0030] 3. Connectors;

[0031] 31. Coordination department;

[0032] 4. Combustion chamber. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0034] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0035] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0036] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0037] Figure 1 is a cross-sectional schematic diagram of an engine provided by the present disclosure, showing a cylinder, a piston and a cylinder head, Figure 2 yes Figure 1 A partial enlarged view of Figure 3 yes Figure 1 In the exemplary embodiment shown, a schematic diagram of the surface of the cylinder head facing the combustion chamber is shown. Figure 4 The simplified diagram of the engine structure provided in this disclosure is: Figure 5 It is a partial cross-sectional schematic diagram of the engine provided by the present disclosure.

[0038] The embodiment of the present disclosure provides an engine, such as Figures 1 to 4As shown, it includes a cylinder 1, a piston 2 and a cylinder head 3, wherein the piston 2 is movably arranged in the cylinder 1, and a convex portion 21 which gradually bulges inwardly in the radial direction is formed on the top edge of the piston 2. The cylinder head 3 is installed on the cylinder 1, and defines a combustion chamber 4 with the cylinder 1 and the piston 2, wherein a matching portion 31 surrounding the combustion chamber 4 is formed on the surface of the cylinder head 3 facing the combustion chamber 4, and the convex portion 21 is configured to form a clearance fit with the matching portion 31 in response to the piston 2 moving upward to the top dead center.

[0039] In such an embodiment, when the piston 2 is located at the bottom dead center, the size of the first space surrounded by the top of the piston 2, the side wall of the cylinder 1 and the cylinder head 3 is the total volume of the cylinder. When the piston 2 moves to the top dead center, the size of the second space surrounded by the top of the piston 2, the side wall of the cylinder 1 and the cylinder head 3 is the combustion chamber volume. At this time, the mixed gas burns normally in the effective volume of the combustion chamber volume, while the mixed gas in the narrow gap between the top of the piston 2 and the cylinder head 3 cannot be fully burned because the flame is difficult to spread. By providing a matching portion 31 matching the raised portion 21 on the top of the piston 2 on the side of the cylinder head 3 facing the combustion chamber 4, that is, the bottom surface of the cylinder head 3, when the piston 2 moves to the top dead center, the raised portion 21 can form a clearance fit with the matching portion 31. The clearance fit prevents or reduces the incomplete combustion of the mixed gas under the premise of ensuring that the piston 2 and the cylinder head 3 do not collide, so that when the compression ratio is increased under the condition of unchanged engine displacement, the emission of pollutants is reduced and the combustion efficiency can be effectively improved.

[0040] In an exemplary embodiment, Figure 2-Figure 3 As shown, the matching portion 31 is configured to be gradually recessed inwardly along the radial direction from the surface edge of the cylinder head 3 facing the combustion chamber 4 to form a clearance fit with the protrusion of the protrusion 21 .

[0041] In such an embodiment, the raised portion 21 is a boss that bulges inward from the edge of the top surface of the piston 2, and the side of the boss is inclined. The matching portion 31 is recessed inward from the edge of the surface of the cylinder head 3 toward the combustion chamber 4. When the piston 2 runs to the top dead center, the boss moves upward with the piston 2 into the recessed part, so that the matching portion 31 forms a gap fit with the side of the boss, and the mixed gas in the combustion chamber 4 is difficult to enter the gap, the incomplete combustion phenomenon is significantly reduced, emissions are reduced, and the negative impact on combustion efficiency is reduced.

[0042] According to the embodiments of the present disclosure, Figure 4 The matching space defined by the matching portion 31 is configured as a truncated cone-shaped space.

[0043] In such an embodiment, the surface of the mating portion 31 is also an annular inclined surface. In other words, the mating surfaces formed by the mating portion 31 and the protrusion 21 are roughly part of the side surface of a cone, or called a conical surface. The conical surface of the mating portion 31 defines a truncated cone-shaped space for accommodating the protrusion 21.

[0044] According to an embodiment of the present disclosure, the cross-section of the truncated cone-shaped space is a trapezoid, and the angle between the two waists of the trapezoidal cross-section is an obtuse angle.

[0045] In such an embodiment, the cross section of the truncated cone-shaped space along the axial direction of the piston is a trapezoid, and the two waists of the trapezoid are the clearance fit positions of the protrusion 21 and the fitting portion 31. By setting the angle between the two waists to be an obtuse angle, the incomplete combustion phenomenon can be reduced as much as possible, and the impact on the airflow can also be reduced.

[0046] For example, when the angle is equal to 180°, no effective gap fit can be formed, or the gap is too large, and a considerable portion of the mixture still suffers from incomplete combustion; when the angle is less than or equal to 90°, although it will make it more difficult for the mixture to enter the gap, it will cause the bulge height of the protrusion 21 to be higher, affecting the flow of the mixture airflow in the combustion chamber 4, and will also have a negative impact on the combustion efficiency.

[0047] Specifically, in Figure 4 In the figure, the upper part is a simplified structural diagram of the engine, showing the protrusion 21 and the matching part 31. Figure 4 The middle part is a three-dimensional schematic diagram after the dotted line is enlarged, showing the truncated cone-shaped space defined by the matching portion 31. Figure 4 The lower part is a cross-sectional diagram of a truncated cone-shaped space, where the angle between the extension lines of the two sides is an obtuse angle, for example Figure 4 or Figure 5 160° shown in FIG.

[0048] Figure 6 yes Figure 1 In the exemplary embodiment shown, a perspective view of the piston head is shown. Figure 7 yes Figure 1 In the exemplary embodiment shown, a schematic plan view of a piston is provided.

[0049] In an exemplary embodiment, Figure 6 to Figure 7 As shown, two protrusions 21 are formed and spaced apart in the circumferential direction, and a flat top 22 coplanar with the top of the piston 2 is formed between the two protrusions 21 .

[0050] In such an embodiment, the combination of the raised portion 21 and the flat top portion 22 is utilized to optimize the airflow movement form, forming a larger-scale tumble flow. The compression process of the piston 2 during the work of the combustion chamber 4 can break up the tumble flow and convert it into stronger turbulent kinetic energy, thereby accelerating combustion, thereby significantly improving the knock tendency and facilitating expansion to the use scenario of large-cylinder engines with high compression ratios.

[0051] More specifically, according to an embodiment of the present disclosure, two protrusions 21 are arranged at both ends of the top of the piston 2 in the radial direction.

[0052] In an exemplary embodiment, a recess 23 is formed at the center of the top of the piston 2, which is suitable for guiding the airflow in the combustion chamber 4 to form a planar vortex.

[0053] In such an implementation mode, by simultaneously providing the protrusion 21 and the recess 23, the air flow movement speed of the combustion chamber 4 during the intake stroke is effectively increased, and the tumble intensity is improved. At the end of the compression of the combustion chamber 4, the protrusion 21 can break up the tumble and convert it into turbulent kinetic energy, thereby accelerating combustion and reducing the tendency of knock.

[0054] In an exemplary embodiment, the surface roughness of the protrusion 21 and / or the matching portion 31 is less than or equal to Ra3.2.

[0055] In such an embodiment, by limiting the roughness to be less than or equal to Ra3.2, it is possible to reduce surface microscopic defects and improve corrosion resistance, while also facilitating tumble flow in the cylinder and reducing flow resistance.

[0056] In an exemplary embodiment, the distance between the protruding portion 21 and the matching portion 31 when they form a clearance fit is d, and 0.5 mm≤d≤1 mm.

[0057] In such an embodiment, by limiting 0.5mm≤d≤1mm, it is possible to ensure that the piston 2 and the cylinder head 3 do not collide, and the proportion of the slit area where incomplete combustion occurs can be reduced, thereby reducing the negative impact on combustion efficiency and emissions when increasing the compression ratio.

[0058] For example, Figures 4 to 5 As shown, the truncated cone-shaped space defined by the matching portion 31 has an angle of 160° between the two waists of its trapezoidal cross section, and the matching clearance between the protrusion 21 and the matching portion 31 is about 0.7 mm. In such an embodiment, it is difficult for the mixed gas to enter the 0.7 mm gap, and the processing accuracy of the protrusion 21 and the matching portion 31 is high, the volume error is small, and the compression ratio deviation is small.

[0059] It will be appreciated by those skilled in the art that the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations or combinations are not explicitly described in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0060] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. An engine, characterized in that: include: Cylinder (1); A piston (2) is movably arranged in the cylinder (1), and a top edge of the piston (2) is formed with a convex portion (21) that gradually bulges inwardly in a radial direction; and A cylinder head (3) is mounted on the cylinder (1) and defines a combustion chamber (4) together with the cylinder (1) and the piston (2); wherein a mating portion (31) surrounding the combustion chamber (4) is formed on a surface of the cylinder head (3) facing the combustion chamber (4), and the protruding portion (21) is configured to form a clearance fit with the mating portion (31) in response to the piston (2) moving upward to the top dead center.

2. The engine according to claim 1, characterized in that The matching portion (31) is configured to gradually recess inwardly along a radial direction from a surface edge of the cylinder head (3) toward the combustion chamber (4) so ​​as to form a clearance fit with the protrusion of the raised portion (21).

3. The engine according to claim 2, characterized in that The matching space defined by the matching portion (31) is configured as a truncated cone-shaped space.

4. The engine according to claim 3, characterized in that The cross section of the truncated cone-shaped space is a trapezoid, and the angle between the two waists of the trapezoidal cross section is an obtuse angle.

5. The engine according to any one of claims 1 to 4, characterized in that: Two protruding portions (21) are formed and are spaced apart in the circumferential direction, and a flat top portion (22) coplanar with the top portion of the piston (2) is formed between the two protruding portions (21).

6. The engine according to claim 5, characterized in that The two protrusions (21) are arranged at both ends of the top of the piston (2) in the radial direction.

7. The engine according to claim 5, characterized in that A recess (23) is also formed at the center of the top of the piston (2), which is suitable for guiding the airflow in the combustion chamber (4) to form a planar vortex.

8. The engine according to any one of claims 1 to 4, characterized in that: The surface roughness of the protruding portion (21) and / or the surface roughness of the matching portion (31) is less than or equal to Ra3.

2.

9. The engine according to any one of claims 1 to 4, characterized in that: The distance between the protruding portion (21) and the matching portion (31) when they form a clearance fit is d, and 0.5 mm≤d≤1 mm.

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