Cylinder head for four-valve diesel engine and diesel engine

Abstract

The present invention discloses a cylinder head for a four-valve diesel engine and a diesel engine, belonging to the field of engine technology. The cylinder head of the present invention includes a cylinder head body formed in one piece by additive manufacturing, and the cylinder head body includes an outer shell, a first supporting structure and a second supporting structure. The first supporting structure and the second supporting structure divide the interior of the outer shell into a plurality of cavities to form a cylinder head body with a porous structure, which reduces the material used and reduces the weight of the cylinder head, while improving the structural strength of the cylinder head. By utilizing the additive manufacturing processing method, different materials are used in different areas of the cylinder head, thereby improving the reliability of the cylinder head, increasing its coordination ability for thermal loads and mechanical loads, and extending the service life of the cylinder head; and different materials can be integrated into one, with high tightness, simple design process, and high yield rate. The diesel engine of the present invention reduces the weight of the engine and shortens the engine design and manufacturing period by applying the above-mentioned cylinder head.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a cylinder head for a four-valve diesel engine and the diesel engine. Background Art

[0002] Diesel engines, with their high torque, excellent economic performance, and wide application, have always occupied a relatively core position in their respective industrial chains. In recent years, as diesel engines have developed towards high power, high reinforcement, and low fuel consumption, people have increasingly tended to use a four-valve-per-cylinder design. Currently, four-valve technology is widely used in four-stroke high-speed diesel engines. Traditional two-stroke low-speed diesel engines generally use a central single exhaust valve. Under normal scavenging conditions, an area of ​​difficult airflow movement is easily formed below the central single exhaust valve, making it difficult to remove combustion exhaust gases and becoming the main source of residual exhaust gas. Therefore, to improve scavenging efficiency, converting the single exhaust valve to a four-valve design is an important development direction for low-speed diesel engines.

[0003] The core difficulty in designing a four-valve diesel engine lies in the cylinder head. A crucial component in a diesel engine, the cylinder head seals the cylinder and, together with the piston, forms the combustion chamber, simultaneously withstanding the high temperature and high pressure of the combustion gases. The internal channel structure of a four-valve diesel engine cylinder head is even more complex. The narrow cylinder head houses not only components such as the injector, indicator valve, intake valve, and exhaust valve holes, but also exhaust ducts and a complex cooling water chamber. Therefore, the cylinder head of a four-valve diesel engine places extremely high demands on the casting core, process, and method, posing significant challenges in both production and quality control.

[0004] Furthermore, the cylinder head operates in a harsh environment, with temperatures varying widely. The bottom firing surface is very hot, while the cooling water jacket is cooler. Temperatures in the intake and exhaust manifolds also vary. Consequently, the cylinder head experiences significant mechanical and thermal stresses. Furthermore, the cylinder head's complex structure creates significant casting residual stresses. Practice has shown that most cylinder head failures are caused by cracks.

[0005] The operating conditions of cylinder heads dictate the high performance requirements of their materials. The uneven temperature and stress distribution of cylinder heads make the use of different materials for each zone the optimal choice, but this is simply not feasible with traditional technologies. Currently, for reinforced four-stroke diesel engines with complex structures, cast steel cylinder heads are often constructed using a welded combination of cast and forged steel components. However, this composite structure is expensive and currently largely unsuitable for practical application. Summary of the Invention

[0006] One object of the present invention is to provide a cylinder head for a four-valve diesel engine, which increases the strength of the cylinder head, extends the service life of the cylinder head, realizes a lightweight design of the cylinder head, and reduces the scrap rate of the cylinder head during processing.

[0007] Another object of the present invention is to provide a diesel engine that reduces the weight of the engine and shortens the engine design and manufacturing period by applying the above-mentioned cylinder head.

[0008] To achieve the above objectives, the following technical solutions are provided:

[0009] In one aspect, a cylinder head for a four-valve diesel engine is provided, comprising a cylinder head body integrally formed by additive manufacturing;

[0010] The cylinder head body includes an outer shell, and a plurality of first support structures are arranged inside the outer shell and spaced apart in sequence along the thickness direction of the cylinder head body. A second support structure is provided between the first support structures, and the first support structure and the second support structure are arranged vertically. The first support structure and the second support structure divide the interior of the outer shell into a plurality of cavities, and the cavities extend along the thickness direction of the cylinder head body.

[0011] As a preferred solution for the cylinder head, a fire surface is provided on the cylinder head body, and the heat resistance temperature and strength of the material selected for the fire surface are greater than those of the material selected for the cylinder head body.

[0012] As a preferred solution for the cylinder head, the material selected for the fire surface is nickel-based alloy, cobalt-based alloy or alloy steel.

[0013] As a preferred solution for the cylinder head, a plurality of bolt holes are provided on the cylinder head body, and the strength of the material selected for the periphery of the bolt holes is greater than that of the material selected for the cylinder head body.

[0014] As a preferred solution for the cylinder head, the material selected for the periphery of the bolt holes is structural steel.

[0015] As a preferred solution for the cylinder head, an air duct is provided on the cylinder head body, and the cross-sectional area of ​​the cavity near the fire surface, the bolt hole and the air duct is smaller than that of the remaining area.

[0016] As a preferred solution of the cylinder cover, the cavity is a circular or polygonal structure.

[0017] As a preferred solution of the cylinder head, the second supporting structure is a honeycomb structure.

[0018] As a preferred solution of the cylinder head, the wall thickness of the cavity ranges from 1 mm to 50 mm; the side length of the cavity ranges from 5 mm to 100 mm; and the height of the cavity is 0.5 to 3 times of its side length.

[0019] In another aspect, a diesel engine is provided, comprising the cylinder head as described above.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The cylinder head of the present invention comprises a cylinder head body integrally formed using additive manufacturing. The cylinder head body comprises an outer shell, a first support structure, and a second support structure. The first and second support structures divide the interior of the outer shell into multiple cavities, forming a porous cylinder head body. This reduces material usage and weight, while also enhancing the structural strength of the cylinder head. By utilizing additive manufacturing methods, different materials are used in different areas of the cylinder head, thereby improving the reliability of the cylinder head, enhancing its ability to cope with thermal and mechanical loads, and extending the service life of the cylinder head. Furthermore, the different materials can be integrated into one body, resulting in a high degree of fit, a simple design process, and a high yield rate.

[0022] The diesel engine of the present invention reduces the weight of the engine and shortens the design and manufacturing period of the engine by applying the cylinder head. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic structural diagram of a cylinder head body from one perspective in an embodiment of the present invention;

[0024] Figure 2 is a structural schematic diagram of the cylinder head body from another perspective in an embodiment of the present invention;

[0025] Figure 3 A longitudinal sectional view of a cylinder head body according to an embodiment of the present invention;

[0026] Figure 4 It is a transverse cross-sectional view of the cylinder head body in an embodiment of the present invention.

[0027] Reference numerals:

[0028] 1. Cylinder head body; 11. Outer shell; 12. First supporting structure; 13. Second supporting structure; 14. Cavity; 15. Fire surface; 16. Bolt hole; 17. Air duct. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0032] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0033] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0034] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0035] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0036] like Figure 1-4As shown, this embodiment provides a cylinder head for a four-valve diesel engine, comprising a cylinder head body 1 integrally formed using additive manufacturing. The cylinder head body 1 comprises an outer shell 11, within which are located a plurality of first support structures 12 spaced sequentially along the thickness of the cylinder head body 1. Second support structures 13 are disposed between the first support structures 12, and are arranged perpendicularly to the first and second support structures 13. The first and second support structures 12, 13 divide the interior of the outer shell 11 into a plurality of cavities 14 extending along the thickness of the cylinder head body 1. The use of additive manufacturing avoids the difficulty of forming complex flow paths in the cylinder head body 1. By abandoning traditional casting processes, the cylinder head body 1 is integrally formed, resulting in a low scrap rate. Furthermore, by breaking away from the constraints of two-dimensional properties of traditional models and directly focusing on three-dimensional design and production, the design process is greatly simplified, thereby significantly shortening the entire design and manufacturing process. It should be understood that the thickness direction of the cylinder head body 1 is the longitudinal direction, with the transverse direction being perpendicular to the longitudinal direction.

[0037] It should be noted that the cylinder head body 1 is formed in one piece by additive manufacturing. The manufacturing principle of layered superposition of additive manufacturing can achieve precise control of material composition, and different materials can be selected in different parts, thereby improving the reliability of the main cylinder head, increasing its coordination ability for thermal load and mechanical load, and extending the service life of the cylinder head body 1. Specifically, a fire surface 15 is provided on the cylinder head body 1, and the heat resistance temperature and strength of the material selected for the fire surface 15 are greater than those of the material selected for the cylinder head body 1. Optionally, the material selected for the fire surface 15 is a nickel-based alloy, a cobalt-based alloy or an alloy steel, which has the advantage of high temperature resistance. Furthermore, a plurality of bolt holes 16 are provided on the cylinder head body 1, and the strength of the material selected around the bolt hole 16 is greater than that of the material selected for the cylinder head body 1. Optionally, the material selected around the bolt hole 16 is structural steel, which has the advantage of high strength.

[0038] It's understandable that the cylinder head body 1 is constructed from a high-thermal-conductivity material to reduce overall thermal stress and extend the life of the cylinder head. However, as part of the combustion chamber, the fire face 15, due to its high peak operating temperature, requires a material with a higher heat resistance and strength than the material used for the cylinder head body 1. This ensures that the cylinder head body 1 maintains a minimum thickness while withstanding the mechanical stresses caused by explosive pressure, thereby reducing the temperature difference between the hot and cold surfaces and preventing thermal fatigue cracking. Furthermore, the area of ​​the cylinder head where the bolt holes 16 are located is a load-bearing area, subject to significant stress, and therefore requires a material with greater strength than the material used for the cylinder head body 1.

[0039] Optionally, an air duct 17 is provided on the cylinder head body 1, and the cross-sectional area of ​​the cavity 14 near the fire surface 15 and around the bolt hole 16 and the air duct 17 is smaller than that of the remaining areas. The size of the cavity 14 near the fire surface 15 and around the bolt hole 16 and the air duct 17 is moderately reduced to improve the structural strength, while the size of the cavity 14 in the remaining areas can be enlarged to achieve the goal of structural optimization. Among them, the air duct 17 includes an intake duct 17 and an exhaust duct 17. It should be noted that the cylinder head body 1 is also provided with an intake port and an exhaust port corresponding to the intake duct 17 and the exhaust duct 17, respectively, as well as a water cavity and other structures. These structures all adopt conventional structures in the prior art and will not be repeated here.

[0040] Optionally, the cavity 14 is a circular or polygonal structure. Preferably, the second support structure 13 is a honeycomb structure. This honeycomb design has excellent geometric mechanical properties. While ensuring structural strength, this regular hexagonal structure can achieve the highest fit and the simplest materials, and can achieve the lightweight design of the cylinder head to the greatest extent. Furthermore, the wall thickness of the cavity 14 ranges from 1mm to 50mm; the side length of the cavity 14 ranges from 5mm to 100mm; and the height of the cavity 14 is 0.5-3 times its side length.

[0041] Optionally, the shapes of the cavities 14 at different parts of the cylinder head body 1 may be the same or different, and the shape can be selected according to specific needs.

[0042] This embodiment also provides a diesel engine, comprising the above-mentioned cylinder head. By using the above-mentioned cylinder head, the weight of the engine is reduced and the engine design and manufacturing period is shortened.

[0043] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A cylinder head for a four-valve diesel engine, characterized in that: It includes a cylinder head body (1) formed in one piece by additive manufacturing; The cylinder head body (1) comprises an outer shell (11), wherein a plurality of first support structures (12) are arranged in sequence along the thickness direction of the cylinder head body (1), and a second support structure (13) is arranged between the first support structures (12). The first support structures (12) and the second support structures (13) are arranged vertically, and the first support structures (12) and the second support structures (13) divide the interior of the outer shell (11) into a plurality of cavities (14), and the cavities (14) extend along the thickness direction of the cylinder head body (1); The cylinder head body (1) is provided with a fire surface (15), and the heat-resistant temperature and strength of the material selected for the fire surface (15) are greater than those of the material selected for the cylinder head body (1); The thickness of the fire surface is the minimum thickness that the cylinder head body (1) can withstand the mechanical stress caused by the explosion pressure, thereby reducing the temperature difference between the hot and cold surfaces; The cylinder head body (1) is provided with a plurality of bolt holes (16), and the strength of the material selected for the periphery of the bolt holes (16) is greater than that of the material selected for the cylinder head body (1); An air passage (17) is provided on the cylinder head body (1), and the cross-sectional area of ​​the cavity (14) near the fire surface (15), the bolt hole (16) and the air passage (17) is smaller than that of the remaining area.

2. The cylinder head according to claim 1, characterized in that: The material selected for the fire surface (15) is nickel-based alloy, cobalt-based alloy or alloy steel.

3. The cylinder head according to claim 1, characterized in that The material selected for the periphery of the bolt hole (16) is structural steel.

4. The cylinder head according to any one of claims 1 to 3, characterized in that: The cavity (14) is a circular or polygonal structure.

5. The cylinder head according to claim 4, characterized in that: The second supporting structure (13) is a honeycomb structure.

6. The cylinder head according to claim 5, characterized in that: The wall thickness of the cavity (14) ranges from 1 mm to 50 mm; the side length of the cavity (14) ranges from 5 mm to 100 mm; and the height of the cavity (14) is 0.5 to 3 times the side length.

7. A diesel engine, characterized in that: Comprising the cylinder head according to any one of claims 1 to 6.

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