Cylinder head and method for its manufacture

Abstract

The invention relates to a cylinder head (1) designed as a casting (2) with at least one cooling water channel (7, 8), wherein at least one heat pipe (5.1, 5.2) is embedded in the casting (2), which thermally connects areas of the casting (2) with higher thermal stress and areas with lower thermal stress, or which is partially embedded in an area of ​​the casting (2) with increased thickness (6) and partially projects into the cooling water channel (7, 8), wherein the at least one heat pipe (5.1, 5.2) is designed as a part with higher thermal conductivity compared to the material of the casting (2), and wherein the heat pipe (5.1, 5.2) has a filling of a liquid or a metal that melts at comparatively low temperatures, in particular sodium, or another melt.

Description

[0001] The invention relates to a cylinder head according to the preamble of claim 1 and a method for manufacturing a cylinder head according to the preamble of claim 6.

[0002] Cylinder heads and other castings for high-power-density engines require highly efficient cooling to prevent thermal and mechanical overload stresses. Therefore, the coolant is directed to where it is needed. However, in some areas of the cylinder head, the casting must be thick enough to withstand the high mechanical forces and temperatures of combustion. The challenge lies in getting sufficient coolant into a cast structure made of high-strength cast iron.

[0003] DE 103 14 906 B4 describes a cylinder head of an internal combustion engine with at least two lift valves per cylinder, which in the closed state each rest on a valve seat, wherein at least one valve seat is surrounded by an annular heat tube, wherein at least two heat tubes are thermally connected and flow-connected to each other.

[0004] The invention is based on the objective of providing a novel cylinder head and a novel method for manufacturing a cylinder head.

[0005] The problem is solved according to the invention by a cylinder head having the features of claim 1 and a method for manufacturing a cylinder head having the features of claim 6.

[0006] Advantageous embodiments of the invention are the subject of the dependent claims.

[0007] A cylinder head is proposed, designed as a casting with at least one cooling water channel. At least one heat pipe is embedded in the casting, thermally connecting areas of the casting with higher thermal stress and areas with lower thermal stress, or partially embedded in an area of ​​the casting with increased thickness and partially projecting into the cooling water channel. The at least one heat pipe is designed as a component with higher thermal conductivity compared to the material of the casting. According to the invention, the heat pipe is filled with a liquid or a metal that melts at comparatively low temperatures, in particular sodium, or another melt.

[0008] According to the present invention, components with high thermal conductivity and / or fillings of liquids or molten metals, for example sodium, are used, which are referred to in the present application as heat pipes. The heat pipe is inserted into a sand mold to obtain a casting with an integrated heat pipe, which connects at least one area subject to high thermal and / or high mechanical stress with at least one area subject to lower thermal stress or directly to the coolant. The heat pipe can be designed as a ring, a tube, or an otherwise shaped structure made of cast iron, steel, or another metal with increased thermal conductivity. The heat pipe can also be used like a column to increase the mechanical stability of the cylinder head in areas where this would not be possible with the casting material.The heat pipe itself, or a coating on the surface of the heat pipe, may be designed to fuse with the casting material.

[0009] The solution according to the invention enables improved cooling of thick or normally less cooled areas of the cylinder head or other cast parts, which can improve service life and / or achieve higher load levels and / or more stable combustion, for example in the case of hydrogen combustion engines.

[0010] The invention increases the thermal conductivity in areas of the casting with high material thickness or in highly stressed areas in order to reduce high temperature levels through improved cooling or connection to better cooled areas. Furthermore, the mechanical robustness of the structure can be maintained or improved.

[0011] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0012] This shows: Fig. 1: a schematic view of a cylinder head, and Fig. 2: Another schematic view of the cylinder head.

[0013] Corresponding parts are marked with the same reference symbols in all figures.

[0014] Fig. Figure 1 is a schematic view of a cylinder head 1 for an internal combustion engine. Fig. Figure 2 is another schematic view of cylinder head 1.

[0015] The internal combustion engine can, for example, be configured to burn hydrogen.

[0016] The internal combustion engine can be used, for example, in a vehicle, especially in a commercial vehicle, a bus or a passenger car.

[0017] The cylinder head 1 is designed as a casting 2 and has areas with higher and lower thermal stress during operation. For example, the cylinder head 1 has at least one exhaust port 3 as an area with higher thermal stress and at least one air intake port 4 as an area with lower thermal stress. At least one heat pipe 5.1 is embedded in the casting 2, which thermally connects areas with higher thermal stress, such as the exhaust ports 3, and areas with lower thermal stress, such as the air intake ports 4. The heat pipe 5.1 can, for example, have the shape of a ring or a crown.

[0018] Furthermore, the casting 2 has areas with increased thickness 6 compared to other areas of the casting 2, which are more difficult to cool due to their greater thickness. One or more heat pipes 5.2 are also incorporated into these areas. The heat pipes 5.2, which are, for example, tubular, are embedded at one end in one of the areas with increased thickness 6 and extend at the opposite end into a cooling water channel 7, 8, for example, an upper cooling jacket 7 or a lower cooling jacket 8.

[0019] The heat pipes 5.1, 5.2 are designed as components with a higher thermal conductivity compared to the material of the casting 2. They can be solid or filled with a liquid, a metal that melts at a comparatively low temperature (e.g., sodium), or another molten material. During the production of the cylinder head 1, at least one heat pipe 5.1, 5.2 is inserted into a sand mold to produce a casting 2 with an integrated heat pipe 5.1, 5.2. The heat pipe 5.1, 5.2 can be made, for example, of cast iron, steel, or another metal with increased thermal conductivity. The heat pipe 5.1, 5.2 can also be used to increase the mechanical stability of the cylinder head 1 in areas where this would not be possible with the casting material. The heat pipe 5.1, 5.2 itself, or a coating on its surface, can be used to create a thermally conductive material.2 can be designed to fuse with the casting material. Reference symbol list 1 cylinder head 2 Cast part 3 Exhaust duct 4 Air intake duct 5.1 Heat pipe 5.2 Heat pipe 6. Area with increased thickness 7. Cooling water channel, upper cooling jacket 8 cooling water channel, lower cooling jacket QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 103 14 906 B4

[0003]

Claims

[1] Cylinder head (1), designed as a casting (2) with at least one cooling water channel (7, 8), wherein at least one heat pipe (5.1, 5.2) is embedded in the casting (2), which thermally connects areas of the casting (2) with higher thermal stress and areas with lower thermal stress, or which is partially embedded in an area of ​​the casting (2) with increased thickness (6) and partially projects into the cooling water channel (7, 8), wherein the at least one heat pipe (5.1, 5.2) is designed as a part with a higher thermal conductivity compared to the material of the casting (2), characterized by , that the heat pipe (5.1, 5.2) has a filling of a liquid or a metal that melts at comparatively low temperatures, in particular sodium, or another melt. [2] Cylinder head (1) according to claim 1, characterized by, that the cylinder head (1) has at least one exhaust port (3) as an area with higher heat load and at least one air intake port (4) as an area with lower heat load. [3] Cylinder head (1) according to claim 1 or 2, characterized by , that the heat pipe (5.1, 5.2) has the shape of a ring or a crown or is tubular in form. [4] Cylinder head (1) according to any one of the preceding claims, characterized by , that the heat pipe (5.1, 5.2) is made of cast iron, steel or another metal with increased thermal conductivity. [5] Cylinder head (1) according to any one of the preceding claims, characterized by , that the material of the heat pipe (5.1, 5.2) or a coating on the surface of the heat pipe (5.1, 5.2) is designed to fuse with the material of the casting (2) during a casting process of the casting (2). [6] Method for producing a cylinder head (1) according to claim 1 by casting in a sand mold, characterized by , that at least one heat pipe (5.1, 5.2) is inserted into the sand mold before casting.

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