Engine piston and engine

Abstract

The utility model provides an engine piston and an engine. The engine piston comprises a piston body. A boss body protruding in the axial direction is arranged at the top of the piston body, the top of the boss body is a table top, and a receding area is formed between the circumferential direction of the boss body and the edge of the top of the piston body. According to the arrangement, the engine piston is designed based on a ridge type combustion chamber, and the boss bodies are distributed in the local area of the top of the piston body, so that when the engine piston moves to an upper dead center, the volume of the combustion chamber can be further reduced; and the design of the clearance area around the boss body also avoids the contact collision between the engine piston and the air valve, so that the compression ratio of the engine is feasibly improved, and the problem of how to improve the compression ratio of the engine with a ridge-shaped combustion chamber in the prior art is solved. When the engine piston is applied to a methanol engine, a higher compression ratio can be obtained, a space is provided, the engine piston is suitable for the combustion working condition of the methanol engine, and space is provided for improving heat efficiency.

Description

Technical Field

[0001] The present application relates to the field of engine technology, and in particular to an engine piston and an engine. Background Art

[0002] In engine-related technologies, the use of methanol as an alternative fuel has become a research and development direction in the field. Methanol has high octane rating and good anti-knock properties. Compared to gasoline engines, methanol-fueled engines have a higher compression ratio and, consequently, higher engine thermal efficiency.

[0003] In an engine, the space between the top of the piston and the bottom of the cylinder head is called the combustion chamber. In spark-ignition methanol engines, especially those with large displacement, some types of combustion chambers are designed as ridge-type combustion chambers. Figure 1 However, the top structure of the piston in the prior art is mostly a flat top structure, which limits the room for improving the engine compression ratio. Therefore, for engines with ridge-type combustion chambers, how to improve the engine compression ratio is particularly important. Utility Model Content

[0004] In view of this, the present application provides an engine piston and an engine to solve the problem of how to improve the engine compression ratio for an engine with a roof-type combustion chamber in the prior art.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] An engine piston includes a piston body;

[0007] The top of the piston body is provided with a boss body protruding in the axial direction, the top of the boss body is a table surface, and there is an escape zone between the circumference of the boss body and the top edge of the piston body.

[0008] Optionally, the side surface of the boss body is tapered.

[0009] Optionally, the boss body is provided with an axially recessed arc-surface pit, and the annular area around the arc-surface pit is the table surface.

[0010] Optionally, the ring edge of the piston body has a taper, and the outer diameter of the ring edge gradually decreases along the direction from the side of the ring edge away from the top of the piston body to the top of the piston body.

[0011] Optionally, the taper of the ring edge is 0.2°-0.5°.

[0012] Optionally, the avoidance area is provided with a avoidance pit recessed relative to the top surface of the piston body, and the avoidance pit is used to avoid the valve;

[0013] A first pit surface and a second pit surface with an included angle are formed in the avoidance pit.

[0014] Optionally, the movement clearance between the first pit surface and the valve side surface is greater than or equal to 2 mm; and / or,

[0015] The movement clearance between the second pit surface and the valve bottom surface is greater than or equal to 1.5 mm.

[0016] Optionally, the first pit surface and the second pit surface are transitionally connected via an arc surface, and the radius of the arc surface is 2mm-5mm.

[0017] Optionally, a cavity is provided in the piston body, and the cavity includes at least an annular cooling oil groove for flowing cooling oil, and the annular cooling oil groove is arranged around the axis of the piston body and is radially opposite to the annular land.

[0018] An engine comprises the engine piston described in any one of the above items, wherein the combustion chamber of the engine is a roof-type combustion chamber.

[0019] The present application provides an engine piston comprising a piston body; the top of the piston body is provided with an axially protruding boss, the top of the boss being a table, and a clearance zone between the boss and the top edge of the piston body. This arrangement allows the engine piston provided in the present application to be based on a ridge-type combustion chamber design. When the engine piston is applied to an engine, the space above the piston top forms the combustion chamber. Because the boss is distributed in a localized area on the top of the piston body, and the top of the boss is a table rather than a conical point, the boss occupies as much space as possible at the same height. This allows the combustion chamber volume to be further reduced when the engine piston reaches top dead center. Furthermore, the clearance zone around the boss prevents contact and collision between the engine piston and the valve, effectively improving the engine compression ratio and resolving the prior art problem of how to improve the engine compression ratio for engines with ridge-type combustion chambers. When the engine piston is applied to a methanol engine, it can achieve a higher compression ratio, providing space suitable for the combustion conditions of a methanol engine and providing room for improved thermal efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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 merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0021] Figure 1 It is a schematic structural diagram of a roof-type combustion chamber of an engine in the prior art;

[0022] Figure 2 An axonometric view of an engine piston provided in an embodiment of the present application;

[0023] Figure 3 A rotating cross-sectional perspective view of an engine piston provided in an embodiment of the present application;

[0024] Figure 4 A cross-sectional view of a boss body provided in an embodiment of the present application;

[0025] Figure 5 A cross-sectional view of the avoidance pit provided in an embodiment of the present application.

[0026] exist Figure 2-Figure 5 middle:

[0027] 1. Piston body; 2. Boss body; 3. Air avoidance area;

[0028] 11. Ring bank; 12. Avoidance pit; 13. Annular cooling oil tank;

[0029] 121, first pit surface; 122, second pit surface; 123, arc surface;

[0030] 21. Table top; 22. Arc pit. DETAILED DESCRIPTION

[0031] 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 in 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.

[0032] like Figure 2-Figure 5 As shown, an embodiment of the present application provides an engine piston suitable for engines with ridge-type combustion chambers, and particularly suitable for methanol engines with ridge-type combustion chambers. The engine piston includes a piston body 1; an axially protruding boss 2 is provided at the top center of the piston body 1. The top of the boss 2 is a table 21, and a clearance zone 3 is defined between the circumference of the boss 2 and the top edge of the piston body 1. The clearance zone 3 is used to prevent contact and collision with the valve. The top of the piston body 1 also encloses one side of the combustion chamber.

[0033] With such a configuration, the engine piston provided in this application is based on a ridge-type combustion chamber design. When the engine piston is applied to an engine, the space above the top of the piston serves as a combustion chamber. Since a boss body 2 is distributed in a local area on the top of the piston body 1, and the top of the boss body 2 is a table 21 rather than a cone-shaped tip, the boss body 2 occupies as much space as possible at the same height. In this way, when the engine piston moves to the top dead center, the volume of the combustion chamber can be further reduced. Moreover, the design of the air avoidance zone 3 around the boss body 2 also avoids contact and collision between the engine piston and the valve, which practically improves the engine compression ratio and solves the problem of how to improve the engine compression ratio for engines with ridge-type combustion chambers in the prior art. When the engine piston is applied to a methanol engine, it can provide space for a higher compression ratio, which is suitable for the combustion conditions of a methanol engine and provides space for improving thermal efficiency.

[0034] In some preferred embodiments, the boss body 2 is truncated cone-shaped, with its sides tapered. This results in a flat top surface and tapered sides, forming a flat-topped cone. This tapered side not only enhances the structural strength of the piston head 1 but also improves compatibility with the ridge-type combustion chamber, thereby increasing compression ratio. Specifically, the taper of the boss body 2's sides is adjusted to correspond to the ridge angle of the cylinder head combustion chamber, ensuring that the sides of the boss body 2 are as parallel to the ridge as possible. This maximizes piston travel and facilitates movement clearance at maximum compression ratio.

[0035] In other preferred embodiments, the boss body 2 is provided with an axially recessed arc surface pit 22 , which can also be called a spherical pit, and an annular area exists in the circumference of the arc surface pit 22 , which is the table surface 21 of the boss body 2 .

[0036] With such an arrangement, the presence of the arc-surface pit 22 is beneficial to increasing the tumble velocity of the mixed gas in the combustion chamber. The tumble can increase the turbulence intensity at the end of compression, accelerate the heat transfer between the burned gas and the unburned gas, thereby increasing the combustion rate, which is beneficial to improving the thermal efficiency of the engine.

[0037] It should be noted that the piston body 1 is produced by casting and the arc-surface pit 22 is formed by machining. Through these two production processes, the axial height of the boss body 2, as well as the diameter and depth of the arc-surface pit 22 can be adjusted, and different compression ratio design structures can be achieved, which brings many feasibility to the optimized design of the methanol engine.

[0038] In addition, the applicant also found that due to the combustion characteristics brought by methanol, compared with traditional gasoline fuel, methanol does not have the function of cleaning carbon deposits and lubricating in the combustion chamber due to its chemical properties. Therefore, the top of the piston and the ring land 11 of the methanol engine are more likely to form carbon deposits and other deposits. The deposits produced by combustion adhere to the piston, which will cause friction and wear between the piston head and the cylinder bore during movement.

[0039] To address the above issues, in some preferred embodiments, the land 11 of the piston body 1 is tapered, with the outer diameter of the land 11 gradually decreasing from the side of the land 11 away from the top of the piston body 1 toward the top of the piston body 1. As is well known in the art, the side of the piston body 1 is provided with multiple piston ring grooves. A land refers to the portion of the piston side between two adjacent piston ring grooves, and the land 11 is the land closest to the piston top surface.

[0040] With such a configuration, the diameter of the ring land 11 is reduced, so that even if carbon deposits generated by combustion adhere to the piston head, the outer diameter of the piston head will not increase excessively, thereby reducing the occurrence of the outer diameter of the piston head increased due to carbon deposits and the contact with the cylinder liner, reducing friction and wear, and improving the reliability and durability of the piston and cylinder liner.

[0041] Furthermore, in some specific embodiments, the taper of the land 11 is between 0.2° and 0.5°, inclusive. Testing and verification have shown that the taper of the land 11 should not be too small, as this will not significantly reduce contact and wear; nor should it be too large, as this will affect airflow within the combustion chamber and cause the combustion conditions to deviate from the preset values. Designs within this taper range significantly reduce friction and wear without affecting airflow within the combustion chamber or the preset combustion conditions.

[0042] In some other preferred embodiments, the avoidance zone 3 is provided with an avoidance pit 12 which is recessed relative to the top surface of the piston body 1, and the avoidance pit 12 is used to avoid the valve. Specifically, two avoidance pits 12 are provided, which respectively avoid the intake valve and the exhaust valve; a first pit surface 121 and a second pit surface 122 with an angle are formed in the avoidance pit 12, or the first pit surface 121 is the side surface, and the second pit surface 122 is the bottom surface; the shape of the avoidance pit 12 is irregularly designed, and the first pit surface 121 and the second pit surface 122 are designed according to the relevant parameters of the valve that needs to be coordinated, for example, determined according to the valve angle and valve lift.

[0043] With such arrangement, the avoidance pit 12 is designed to prevent the piston from colliding with the valve during engine operation due to the rise of the piston top surface and the reduction of the clearance between the piston and the valve.

[0044] In some specific embodiments, the movement clearance between the first pit surface 121 and the side surface of the valve is greater than or equal to 2 mm; in addition, the movement clearance between the second pit surface 122 and the bottom surface of the valve is greater than or equal to 1.5 mm.

[0045] With this setting, since the combustion chamber will be hot when the engine is running and will gradually cool down when the engine is stopped, taking into account the factors of thermal expansion and contraction of valves and pistons, after testing and verification, the motion clearance is set to the above range, which can accommodate the volume expansion under thermal expansion without causing valve and piston collision.

[0046] In some other preferred embodiments, the first pit surface 121 and the second pit surface 122 are transitionally connected by an arc surface 123 , and the radius of the arc surface 123 is 2 mm-5 mm, including both end points.

[0047] In this arrangement, due to the forging processing factors of the avoidance pit 12, the designed arc surface 123 of the avoidance pit 12 cannot be too small, otherwise it will be difficult to process and shape. At the same time, the arc surface 123 of the avoidance pit 12 cannot be too large, which will reduce the movement gap between the avoidance pit 12 and the valve. After testing and verification, when the radius of the transition arc surface 123 between the first pit surface 121 and the second pit surface 122 meets the above range, the avoidance pit 12 is adapted to the arc design between the bottom surface of the valve and the side surface of the valve, and at the same time can meet the design requirements of the movement gap and facilitate the processing of the avoidance pit 12.

[0048] It should be noted that the previous description of valves applies to both intake valves and exhaust valves.

[0049] In other optional embodiments, a cavity is provided within the piston body 1, comprising at least an annular cooling oil groove 13 for the flow of cooling oil. Annular cooling oil groove 13 is disposed about the axis of the piston body 1 and radially opposed to the piston land. This allows cooling oil from the piston cooling nozzle to be directed into annular cooling oil groove 13, thereby ensuring adequate cooling of the piston land. Generally, the piston cooling nozzle is mounted on the bottom side of the piston body 1.

[0050] The engine piston provided in this application is a steel part. The use of steel material improves the overall rigidity compared to traditional ignition-type aluminum pistons.

[0051] In summary of the above embodiments, the engine piston provided in the present application has a more excellent tumble ratio, better air flow velocity, and higher compression ratio through structural design, thereby improving the thermal efficiency of the engine; it can also meet the high compression ratio requirements of the methanol engine, and can also achieve different compression ratio requirements through machining; in addition, it can effectively reduce the deposits generated by combustion adhering to the piston, resulting in friction and wear between the piston head and the cylinder bore during movement, thereby improving the reliability and durability of the engine.

[0052] Based on the aforementioned engine piston, an embodiment of the present application further provides an engine, comprising the aforementioned engine piston, wherein the engine combustion chamber is a ridge-shaped combustion chamber. Since the engine comprises the aforementioned engine piston, the beneficial effects of the engine and the engine piston are described above and are not further elaborated here.

[0053] Furthermore, the engine may be a methanol engine in particular. Spark-ignition large-displacement methanol engines often use a roof-type combustion chamber structure, and the above-mentioned engine piston can be well adapted.

[0054] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0055] The block diagrams of the devices, devices, equipment, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, devices, equipment, and systems can be connected, arranged, or configured in any manner. Words such as "include," "comprise," "have," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0056] It should also be noted that in the apparatus, device, and method of the present application, each component or each step can be decomposed and / or recombined, and such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0057] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0058] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly illustrate the technical solutions and cannot be used to limit the scope of protection of the present application.

[0059] The above description has been provided for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. An engine piston, characterized in that: It comprises a piston body (1); The top of the piston body (1) is provided with a boss body (2) protruding in the axial direction, the top of the boss body (2) is a table surface (21), and there is an air gap (3) between the circumference of the boss body (2) and the top edge of the piston body (1).

2. The engine piston according to claim 1, characterized in that The side surface of the boss body (2) has a taper.

3. The engine piston according to claim 1 or 2, characterized in that: The boss body (2) is provided with an axially recessed arc-surface pit (22), and the annular area in the circumferential direction of the arc-surface pit (22) serves as the table surface (21).

4. The engine piston according to claim 1, characterized in that The annular land (11) of the piston body (1) has a taper, and the outer diameter of the annular land (11) gradually decreases along the direction from the side of the annular land (11) away from the top of the piston body (1) to the top of the piston body (1).

5. The engine piston according to claim 4, characterized in that The taper of the ring bank (11) is 0.2°-0.5°.

6. The engine piston according to claim 1, characterized in that The avoidance area (3) is provided with a avoidance pit (12) that is recessed relative to the top surface of the piston body (1), and the avoidance pit (12) is used to avoid the valve; A first pit surface (121) and a second pit surface (122) having an included angle are formed in the avoidance pit (12).

7. The engine piston according to claim 6, characterized in that The movement clearance between the first pit surface (121) and the valve side surface is greater than or equal to 2 mm; and / or, The movement clearance between the second pit surface (122) and the valve bottom surface is greater than or equal to 1.5 mm.

8. The engine piston according to claim 6, characterized in that The first pit surface (121) and the second pit surface (122) are transitionally connected via an arc surface (123), and the radius of the arc surface (123) is 2 mm to 5 mm.

9. The engine piston according to claim 1, characterized in that A cavity is provided in the piston body (1), and the cavity at least includes an annular cooling oil groove (13) for flowing cooling oil. The annular cooling oil groove (13) is arranged around the axis of the piston body (1) and is radially opposite to the annular land.

10. An engine, characterized in that: The engine piston comprises the engine piston according to any one of claims 1 to 9, wherein the combustion chamber of the engine is a roof-type combustion chamber.

Images