Piston top, piston and diesel engine

Abstract

The invention provides a piston crown, a piston and a diesel engine, the piston crown comprises a piston outer surface layer, a piston inner surface layer and a filling layer, the piston outer surface layer and the piston inner surface layer define a containing space, and the containing space is filled with the filling layer; the filling layer comprises a plurality of crystal lattice structures, at least one liquid inlet and at least one liquid outlet which are communicated with the containing space are formed in the inner surface layer of the piston, and first cooling flow channels are formed among the liquid inlets, gaps among the crystal lattice structures in the filling layer and the liquid outlets; the first cooling flow channel is configured in the mode that cooling lubricating oil can flow into the containing space through the liquid inlet and flow to the liquid outlet through gaps between the lattice structures to flow out.

Description

Technical Field

[0001] This invention relates to the field of diesel engine performance optimization technology, specifically to a piston top, a piston, and a diesel engine. Background Technology

[0002] As one of the key components of a diesel engine, the piston is responsible for forming the combustion chamber and reciprocating under the impetus of high-temperature combustion gases.

[0003] The harsh working environment of high temperature and high pressure dictates that pistons must possess high structural strength to ensure reliability. Currently, piston structural strength is generally improved by increasing the piston's structural dimensions or using high-strength materials. However, increasing the piston's structural dimensions increases its volume and weight, while using high-strength materials leads to high costs.

[0004] Based on this, the inventors of this application propose a piston top, a piston, and a diesel engine to solve one or more of the aforementioned technical problems. Summary of the Invention

[0005] The present invention solves the above-mentioned technical problems through the following technical solution: The first aspect of the present invention provides a piston top, comprising: The piston comprises an outer surface layer, an inner surface layer, and a filling layer, wherein the outer surface layer and the inner surface layer enclose a receiving space, and the filling layer fills the receiving space. The filling layer includes multiple lattice structures, and the inner surface of the piston has at least one liquid inlet and at least one liquid outlet communicating with the accommodating space. The liquid inlet, the gap between the lattice structures in the filling layer, and the liquid outlet form a first cooling channel. The first cooling channel is configured such that cooling oil can flow through the inlet into the accommodating space and through the gaps between the lattice structures to the outlet.

[0006] This invention fills the space 4 between the outer and inner surfaces of the piston with multiple lattice structures. Utilizing the high specific strength and low bulk density of these lattice structures, the overall weight of the piston crown is significantly reduced while still meeting the structural strength requirements for withstanding high-temperature combustion gas pressure and reciprocating mechanical loads. Furthermore, the gaps between the lattice structures, along with the inlet and outlet, form a first cooling channel, significantly increasing the heat exchange contact area between the cooling oil and the piston crown. This further ensures the stability of the cooling effect and helps extend the service life of the piston crown.

[0007] According to one embodiment of the present invention, the inner surface of the piston is recessed in the middle to form a first cooling chamber, and the liquid outlet is opened at the top of the first cooling chamber; The inner surface of the piston is coaxially surrounded by a second cooling chamber, and the liquid inlet is located at the top of the second cooling chamber. The cooling oil flows from the inlet of the second cooling chamber to the accommodating space and from the outlet to the first cooling chamber.

[0008] According to one embodiment of the present invention, along the flow direction of the cooling lubricating oil into the accommodating space, the inlet is positioned higher than the outlet along the axial direction of the piston top.

[0009] According to one embodiment of the present invention, the number of liquid inlets is at least two, and the at least two liquid inlets are evenly distributed around the top circumference of the second cooling cavity.

[0010] According to one embodiment of the present invention, there are multiple liquid outlets, at least one of which is located at the top of the first cooling chamber, and at least one of which is also located at the bottom end face of the piston and communicates with the accommodating space.

[0011] According to one embodiment of the present invention, a plurality of connecting channels are further provided between the first cooling chamber and the second cooling chamber, and the axial direction of the connecting channels is set at an angle to the axial direction of the piston top, and the angle is an acute angle; The first cooling chamber, the connecting channel, and the second cooling chamber constitute a second cooling channel. The second cooling channel is configured such that cooling lubricating oil flows through the second cooling chamber into the connecting channel and is discharged through the first cooling chamber.

[0012] According to one embodiment of the present invention, the lattice structure includes lattice nodes and a plurality of lattice trusses, wherein the plurality of lattice trusses are arranged circumferentially around the lattice nodes.

[0013] According to one embodiment of the present invention, the plurality of lattice structures include a plurality of first lattice lattice units and a plurality of second lattice lattice units, the accommodating space having a first region and a second region, the first lattice lattice units being disposed in the first region, and the second lattice lattice units being disposed in the second region; wherein... The first region experiences greater force than the second region, and the density of the lattice truss corresponding to a single lattice node in the first lattice unit is greater than the density of the lattice truss corresponding to a single lattice node in the second lattice unit.

[0014] According to one embodiment of the present invention, the first region includes a region near the center of the piston top and a region on the piston top for mounting with the piston skirt.

[0015] According to one embodiment of the present invention, the outer surface layer of the piston, the inner surface layer of the piston, and the lattice structure are made of the same material and are all made of high-strength alloy steel.

[0016] According to one embodiment of the present invention, the outer surface layer of the piston, the inner surface layer of the piston, and the lattice structure are manufactured by additive manufacturing.

[0017] A second aspect of the invention also provides a piston, including the piston top as described above.

[0018] A third aspect of the invention also provides a diesel engine, including the piston described above. Attached Figure Description

[0019] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the piston top structure of the present invention; Figure 2 for Figure 1 A partial cross-sectional view of the piston top; Figure 3 for Figure 1 A cross-sectional view of the piston top at an angle; Figure 4 for Figure 2 A schematic diagram of a medium lattice structure.

[0020] 1. Piston outer surface layer; 2. Piston inner surface; 21. Liquid inlet; 22. Liquid outlet; 23. First cooling channel; 24. First cooling chamber; 25. Second cooling chamber; 26. Connecting channel; 3. Filling layer; 31. Lattice structure; 32. Lattice node; 33. Lattice truss; 34. First lattice unit; 35. Second lattice unit; 4. Storage space; 5. First area; 6. Second area. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0023] Please refer to Figures 1 to 4 To address the challenge of simultaneously achieving structural strength, lightweight design, and efficient cooling in existing pistons, this invention proposes a piston top comprising an outer piston layer 1, an inner piston layer 2, and a filling layer 3. The outer piston layer 1 and the inner piston layer 2 enclose a accommodating space 4, and the filling layer 3 fills the accommodating space 4. The filling layer 3 includes multiple lattice structures 31. The inner piston layer 2 has at least one inlet 21 and at least one outlet 22 communicating with the accommodating space 4. A first cooling channel 23 is formed between the inlet 21, the gaps between the lattice structures 31 in the filling layer 3, and the outlet 22. The first cooling channel 23 is configured such that cooling oil can flow through the inlet 21 into the accommodating space 4 and through the gaps between the lattice structures 31 to the outlet 22.

[0024] For composite pistons, the piston crown, which bears a large mechanical load and thermal load, is an important component for improving structural strength and reducing weight. It must ensure that the piston has the necessary structural strength under its effective weight, and also ensure that the structure has a strong cooling capacity.

[0025] Based on this, the present invention forms a accommodating space 4 in the outer surface layer 1 and the inner surface layer 2 of the piston, and fills the accommodating space 4 with a plurality of lattice structures 31. The lattice structures 31 ensure that the external load is uniformly applied to each lattice structure 31 and transferred to the piston skirt below. At the same time, a large gap space is formed between the lattice structures 31, which, while satisfying the requirements of lightweighting, is conducive to forming a first cooling flow channel 23 with the liquid inlet 21 and the liquid outlet 22, which facilitates the increase of the contact area between the cooling lubricating oil and the outer surface layer 1 of the piston, thereby improving the cooling effect of the piston top combustion chamber and reducing the heat load on the piston top.

[0026] It can be seen that the cooling oil entering the accommodating space 4 through the inlet 21 flows in the gaps of the lattice structure 31, so the cooling oil can fill the accommodating space 4, thereby efficiently carrying away the heat in the accommodating space 4, thus improving the uniformity of the overall cooling of the piston top.

[0027] Please continue to refer to Figure 3The piston inner surface layer 2 is recessed in the middle to form a first cooling chamber 24, and the liquid outlet 22 is opened at the top of the first cooling chamber 24; the piston inner surface layer 2 is coaxially arranged around the first cooling chamber 24 to form a second cooling chamber 25, and the liquid inlet 21 is opened at the top of the second cooling chamber 25; the cooling lubricating oil flows through the liquid inlet 21 of the second cooling chamber 25 to the accommodating space 4 and flows through the liquid outlet 22 to the first cooling chamber 24 and out.

[0028] like Figure 3 As shown, the piston top has a raised structure in the center, and the central part of this raised structure is concave to form a hemispherical first cooling chamber 24. The liquid outlet 22 is opened at the top of the first cooling chamber 24. A second cooling chamber 25 is formed around the outer periphery of the first cooling chamber 24, and the liquid inlet 21 is opened at the top of the second cooling chamber 25. It should be noted that the shape of the raised structure is only an example here, and the first cooling chamber 24 is also described using a hemispherical shape as an example, but it is not a limitation.

[0029] Please refer to Figure 1 and Figure 3 During piston operation, the outer surface layer 1, from the piston throat to the center of the combustion chamber, is a high-temperature region. Figure 1 The area between the dashed lines A and B. In this application, the inlet 21 is located close to the outer periphery, that is, close to position A. After the cooling oil enters the accommodating space 4 through the inlet 21, it will flow in the direction from A to B, thereby achieving efficient cooling of the high-temperature area of ​​the piston outer surface 1.

[0030] In one implementation, please refer to Figure 3 Along the flow direction of the cooling lubricating oil into the accommodating space 4, the inlet 21 is positioned higher than the outlet 22 along the axial direction of the piston top.

[0031] Figure 3 The dashed arrows in the second cooling chamber 25 indicate the flow direction of the cooling oil, corresponding to an upward direction. For example... Figure 3 As shown, the inlet 21 is axially higher than the outlet 22. This height difference allows for the formation of a natural flow driving force, guiding the cooling oil to flow unidirectionally and continuously from the second cooling chamber 25 through the accommodating space 4 to the first cooling chamber 24. This avoids the problem of oil stagnation caused by the reciprocating motion of the piston.

[0032] This application optimizes the flow characteristics of cooling lubricating oil by utilizing gravitational potential energy. It does not require an additional power device, which can reduce energy consumption. Furthermore, the lubricating oil that continuously flows in and out of the accommodating space 4 can promptly remove the heat from the piston top, avoiding thermal deformation or ablation caused by heat accumulation in the dead zone, and further improving the cooling effect of the piston top.

[0033] Please continue to refer to Figure 3The number of liquid inlets 21 is at least two, and the at least two liquid inlets 21 are evenly distributed around the top circumference of the second cooling chamber 25.

[0034] At least two circumferentially distributed liquid inlets 21 allow cooling oil to flow synchronously from multiple points around the outer periphery of the second cooling chamber 25 into the receiving space 4. The oil is evenly distributed at the inlet of the receiving space 4, avoiding cooling blind spots in local areas due to insufficient oil supply. Moreover, the design of multiple liquid inlets 21 is adapted to the annular heat load distribution around the piston crown, enabling targeted cooling of high-heat areas such as the piston crown ring groove and the combustion chamber edge, improving the overall cooling uniformity of the piston crown. At the same time, multiple liquid inlets can reduce the flow pressure of a single liquid inlet 21, avoiding heat exchange delays caused by oil throttling.

[0035] Furthermore, there are multiple liquid outlets 22, at least one of which is located at the top of the first cooling chamber 24, and at least one of which is also located at the bottom end face of the piston and communicates with the accommodating space 4.

[0036] like Figure 1 As shown, the first cooling chamber 24 has a liquid outlet 22 on its top, but the number is not limited to this. At the top and bottom end faces of the piston, multiple liquid outlets 22 can be opened along its circumference, and the specific number is not limited.

[0037] It is known that the outlet 22 of the first cooling chamber 24 can quickly discharge hot oil from the central area of ​​the accommodating space 4, while the outlet 22 on the bottom face of the piston top can specifically discharge heat from the lower area of ​​the filling layer 3, preventing heat from accumulating at the bottom of the piston top. The outlets 22 at different positions can form multi-path drainage channels, which helps to improve the lubricating oil circulation rate, ensure continuous and efficient renewal of cooling lubricating oil, further reduce the overall temperature gradient of the piston top, and reduce the risk of cracks caused by thermal stress.

[0038] In one embodiment, a plurality of connecting channels 26 are provided between the first cooling chamber 24 and the second cooling chamber 25. The axial direction of the connecting channel 26 is set at an angle to the axial direction of the piston top, and the angle is an acute angle. The first cooling chamber 24, the connecting channel 26 and the second cooling chamber 25 constitute a second cooling flow channel. The second cooling flow channel is configured such that cooling lubricating oil flows through the second cooling chamber 25 into the connecting channel 26 and is discharged through the first cooling chamber 24.

[0039] That is, when the piston reciprocates, the cooling oil oscillates at the top of the first cooling chamber 24 and the second cooling chamber 25 under the constraint of the piston's inner surface layer 2. During the oscillation, a portion of the oil enters the accommodating space 4 through the inlet 21 and fills the accommodating space 4 as the piston moves. Subsequently, under the reciprocating motion of the piston and the action of gravity, it is discharged from the outlet 22. The amount of cooling oil flowing into the accommodating space 4 is dynamically balanced with the amount discharged, and it can efficiently carry away the heat in the filling layer 3. The remaining portion flows from the second cooling chamber 25 to the first cooling chamber 24 through the connecting channel 26.

[0040] When the cooling oil reaches the inlet 21, it will collect around the inlet 21. Part of the collected cooling oil flows through the inlet 21, while the rest flows through the connecting channel 26 to the first cooling chamber 24. This part of the cooling oil will, on the one hand, cool the top wall of the first cooling chamber 24 to a certain extent, thereby improving the cooling effect in the middle area of ​​the piston outer surface layer 1. On the other hand, it can carry away the cooling oil, forming a cooling circulation path.

[0041] Please refer to Figure 4 For the lattice structure 31, it includes lattice nodes 32 and multiple lattice trusses 33, which are arranged circumferentially around the lattice nodes 32.

[0042] The circumferentially arranged lattice truss 33 forms a stable force-bearing system around the lattice nodes 32, which can evenly transfer the mechanical load and heat flow borne by the piston top to the entire structure of the piston top, avoiding local stress concentration at the piston top. Moreover, the truss structure can further reduce the amount of material used while ensuring strength, thus enhancing the lightweight effect.

[0043] Specifically, the lattice structure 31 includes a plurality of first lattice lattice units 34 and a plurality of second lattice lattice units 35. The accommodating space 4 has a first region 5 and a second region 6. The first lattice lattice units 34 are disposed in the first region 5, and the second lattice lattice units 35 are disposed in the second region 6. The first region 5 is subjected to greater force than the second region 6, and the arrangement density of the lattice truss 33 corresponding to a single lattice node 32 in the first lattice lattice unit 34 is greater than the arrangement density of the lattice truss 33 corresponding to a single lattice node 32 in the second lattice lattice unit 35.

[0044] Optionally, the first region 5 includes a region near the center of the piston top and a region on the piston top for mounting with the piston skirt.

[0045] With this configuration, the first region 5, as the core load-bearing part of the piston top, directly faces the impact of the high-temperature, high-pressure combustion gases in the combustion chamber, while the piston skirt installation area needs to transfer the total load on the piston top, resulting in a more concentrated and complex stress. This invention significantly enhances the structural strength and deformation resistance of this region by increasing the density of the lattice trusses 33 corresponding to individual lattice nodes 32 in the first lattice unit 34, ensuring that the core load-bearing part can stably withstand the load without failure. The second region 6 experiences relatively gentler stress; therefore, using the second lattice unit 35 with a lower truss density allows for minimizing material usage while meeting the basic structural support requirements, further enhancing the lightweight effect of the piston top.

[0046] Optionally, the diameter of the lattice truss 33 corresponding to a single lattice node 32 in the first lattice unit 34 within the first region 5 is greater than the diameter of the lattice truss 33 corresponding to a single lattice node 32 in the second lattice unit 35 within the second region 6.

[0047] In one embodiment, the piston outer surface layer 1, the piston inner surface layer 2, and the lattice structure 31 are made of the same material and are all made of high-strength alloy steel.

[0048] For example, the piston outer surface layer 1, piston inner surface layer 2, and lattice structure 31 can be made of 42CrMoA high-strength alloy, which enables the piston outer surface layer 1, piston inner surface layer 2, and lattice structure 31 to have consistent mechanical strength and thermal conductivity, thereby enabling them to withstand the high temperature and high pressure conditions of the diesel engine. Furthermore, material consistency can avoid interface separation or cracking caused by uneven thermal expansion, which helps extend the service life of the piston crown. In some other embodiments, the piston outer surface layer 1, piston inner surface layer 2, and lattice structure 31 can also be made of other high-strength alloy materials, which are not limited here.

[0049] In one embodiment, the piston outer surface layer 1, the piston inner surface layer 2, and the lattice structure 31 are manufactured by additive manufacturing.

[0050] Additive manufacturing facilitates the precise realization of complex topological structures of crystal lattices and the irregularly shaped chamber designs of the first cooling chamber 24 and the second cooling chamber 25, thereby avoiding problems such as lattice structure damage or chamber splicing leakage caused by traditional casting and machining processes. Moreover, integrated molding also helps to improve the overall integrity and sealing of the piston top components, reducing the risk of lubricating oil leakage caused by splicing gaps.

[0051] The present invention also proposes a piston, including the piston top described above.

[0052] As can be seen, the piston of the present invention, with the advantages of high strength, lightweight and efficient cooling of the piston top, has a significantly improved overall resistance to harsh working conditions, thus being able to stably withstand mechanical shocks and thermal loads during reciprocating motion; moreover, the lightweight design of the piston top can reduce the reciprocating inertial force of the piston, reduce cylinder liner wear, and thus optimize the smoothness of diesel engine power output; the efficient cooling advantage of the piston top can prevent the piston from overheating as a whole and extend the service life of the piston and related components such as cylinder liners and piston rings.

[0053] The present invention also proposes a diesel engine comprising the piston described above.

[0054] The use of the aforementioned pistons in diesel engines helps to improve their power output efficiency, power reliability, and durability.

[0055] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation", "connection", "joining", and "fixing" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can also refer to mechanical connections. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0056] This application uses specific terms to describe embodiments of the application. Terms such as "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0057] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A piston top, characterized in that, include: The piston comprises an outer surface layer, an inner surface layer, and a filling layer, wherein the outer surface layer and the inner surface layer enclose a receiving space, and the filling layer fills the receiving space. The filling layer includes multiple lattice structures, and the inner surface of the piston has at least one liquid inlet and at least one liquid outlet communicating with the accommodating space. The liquid inlet, the gap between the lattice structures in the filling layer, and the liquid outlet form a first cooling channel. The first cooling channel is configured such that cooling oil can flow through the inlet into the accommodating space and through the gaps between the lattice structures to the outlet.

2. The piston top according to claim 1, characterized in that, The piston has a concave inner surface layer in the middle to form a first cooling chamber, and the liquid outlet is located at the top of the first cooling chamber. The inner surface of the piston is coaxially surrounded by a second cooling chamber, and the liquid inlet is located at the top of the second cooling chamber. The cooling oil flows from the inlet of the second cooling chamber to the accommodating space and from the outlet to the first cooling chamber.

3. The piston top according to claim 2, characterized in that, Along the flow direction of the cooling lubricating oil into the accommodating space, the inlet is positioned higher than the outlet along the axial direction of the piston top.

4. The piston top according to claim 2, characterized in that, The number of liquid inlets is at least two, and the at least two liquid inlets are evenly distributed around the top circumference of the second cooling cavity.

5. The piston top according to claim 2, characterized in that, The number of liquid outlets is multiple, at least one of which is located at the top of the first cooling chamber, and at least one of which is also located at the bottom end face of the piston and communicates with the accommodating space.

6. The piston top according to claim 2, characterized in that, A plurality of connecting channels are provided between the first cooling chamber and the second cooling chamber. The axial direction of the connecting channel is set at an angle to the axial direction of the piston top, and the angle is an acute angle. The first cooling chamber, the connecting channel, and the second cooling chamber constitute a second cooling channel. The second cooling channel is configured such that cooling lubricating oil flows through the second cooling chamber into the connecting channel and is discharged through the first cooling chamber.

7. The piston top according to claim 1, characterized in that, The lattice structure includes lattice nodes and multiple lattice trusses, with the multiple lattice trusses arranged circumferentially around the lattice nodes.

8. The piston top according to claim 7, characterized in that, The plurality of said lattice structures include a plurality of first lattice lattice units and a plurality of second lattice lattice units. The accommodating space has a first region and a second region. The first lattice lattice units are disposed in the first region, and the second lattice lattice units are disposed in the second region. The first region experiences greater force than the second region, and the density of the lattice truss corresponding to a single lattice node in the first lattice unit is greater than the density of the lattice truss corresponding to a single lattice node in the second lattice unit.

9. The piston top according to claim 8, characterized in that, The first region includes a region near the center of the piston top and a region on the piston top for mounting with the piston skirt.

10. The piston top according to claim 1, characterized in that, The outer surface layer of the piston, the inner surface layer of the piston, and the lattice structure are all made of the same material, and all are made of high-strength alloy steel.

11. The piston top according to claim 1, characterized in that, The outer surface layer of the piston, the inner surface layer of the piston, and the lattice structure are manufactured by additive manufacturing.

12. A piston, characterized in that, Includes the piston top as described in any one of claims 1-11.

13. A diesel engine, characterized in that, Includes the piston as described in claim 12.

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