Core assembly for a cylinder head

Abstract

The invention relates to a core assembly (1) for a cylinder head (2) of an internal combustion engine, comprising at least one single-piece lost core (10), in particular a sand core, which has a plurality of core regions (11, 12, 13, 14, 15) for functionally different sections of the cylinder head (2), wherein, for at least one cylinder (20), a first core region (11) has at least one first mould surface (11a) for at least one inlet channel (21) opening into a combustion chamber roof (22) of the cylinder head via at least one inlet opening (21a), and a second core region (12) has at least one second mould surface (12a) for at least one part of a combustion chamber roof (22). In order to reduce the manufacturing complexity for a cylinder head (2), according to the invention the second core region (12) has at least one first chamfer forming surface (12b) for a region (22b) generating a charge movement around the inlet opening (21a) of the combustion chamber roof (22).

Description

[0001] Core arrangement for a cylinder head

[0002] The invention relates to a core arrangement for a cylinder head of an internal combustion engine, comprising at least one one-piece lost core, in particular a sand core, which has several core areas for functionally different sections of the cylinder head, wherein for at least one cylinder a first core area has at least a first shaped surface for at least one intake port opening into a combustion chamber roof of the cylinder head via at least one intake port, and a second core area has at least a second shaped surface for at least a part of a combustion chamber roof. The invention further relates to a cylinder head manufactured with this core arrangement.

[0003] EP 0 958 076 Al discloses a method and a core for shaping hollow areas of a cylinder head of an internal combustion engine, wherein a single one-piece core forms the combustion chamber and the intake ports.

[0004] Areas of the combustion chamber roof that generate charge motion, such as chamfers around valve seats, are typically machined in a separate manufacturing step to remove material in order to meet accuracy requirements. Such machining is relatively complex and expensive.

[0005] The purpose of the invention is to reduce the manufacturing effort for a cylinder head.

[0006] According to the invention, this problem is solved with a core arrangement of the type mentioned above by the fact that the second core area has at least a first chamfered surface for a charge movement generating area around the inlet opening of the combustion chamber ceiling.

[0007] Advantageously, the second molded surface of the second core area of ​​the one-piece lost core forms the entire combustion chamber ceiling of at least one cylinder. This allows for core savings, reduces tolerances between the intake port and the combustion chamber ceiling, and generates free surfaces.

[0008] The charge-generating area is formed by the one-piece expendable core. No material removal is required in this area, significantly reducing manufacturing costs. The one-piece core design allows for minimal tolerances, enabling high accuracy without subsequent material removal.

[0009] Advantageously, the first chamfered surface of the second core area is arranged adjacent to the first core area.

[0010] Preferably, the first chamfered surface of the second core region is formed by a ramp surface around the first core region, inclined to the second chamfered surface and preferably substantially conical. The ramp surface of the second core region forms the charge-movement-generating area around the inlet opening.

[0011] Optimal charge movement can be achieved if the first chamfered surface extends around the inlet opening by an angular range of at least 120°, preferably at least 150°.

[0012] One embodiment according to the invention provides that the second core area additionally forms at least a second chamfered surface for a run-out area around an outlet opening.

[0013] In one embodiment of the invention, a third core area of ​​the one-piece lost core forms at least a third forming surface for an exhaust port. The one-piece lost core forms not only one or more intake ports and at least part of the combustion chamber roof per cylinder, but also at least one exhaust port. This allows for a reduction in the number of cores required and a decrease in tolerances between the intake port, combustion chamber roof, and exhaust port.

[0014] The second chamfered forming surface is preferably formed by a ramp surface around the third core area, inclined to the second forming surface and preferably essentially conical and circumferential.

[0015] Another embodiment of the invention provides that a fourth core area of ​​the one-piece expendable core forms at least a fourth forming surface for a coolant channel and / or a lubricating oil channel. The one-piece expendable core forms not only one or more intake ports and at least a portion of the combustion chamber roof per cylinder, but also at least one coolant channel and / or at least one lubricating oil channel. This allows for a reduction in the number of cores required and a decrease in tolerances between the intake port, combustion chamber roof, and coolant channel and / or lubricating oil channel. Furthermore, the invention provides that at least one one-piece expendable core is manufactured using an additive manufacturing process. This enables high accuracy and also the complex shaping of cylinder head cavities.

[0016] The object of the invention is further achieved by a cylinder head manufactured with the described core arrangement in that at least one charge-generating area is arranged around an intake port in the region of the combustion chamber roof, which is manufactured by casting without material removal. The charge-generating areas, formed with high precision and low tolerances by the lost one-piece core, no longer require material removal. This significantly reduces manufacturing effort. Preferably, the charge-generating area is formed by a chamfer around the intake port, which is inclined to an intake port plane perpendicular to an intake port axis in the region of the intake port. A first angle of inclination between the intake port plane and the charge-generating area can be approximately 10° to 40°.

[0017] In a further embodiment of the invention, it can be provided that at least one outlet area is formed by a second chamfer around the outlet opening, which is inclined to an outlet opening plane normal to an outlet channel axis in the area of ​​the outlet opening, wherein preferably a second angle of inclination between the outlet opening plane and the outlet area is approximately 10° to 40°.

[0018] The invention will be explained in more detail below with reference to the figures. These show:

[0019] Fig. 1 shows a core arrangement according to the invention in a first embodiment in an axonometric representation;

[0020] Fig. 2 shows a core arrangement according to the invention in a second embodiment in an axonometric representation;

[0021] Fig. 3 shows a cylinder head according to the invention in an axonometric view from the side of the combustion chamber;

[0022] Fig. 4 shows the cylinder head in a bottom view;

[0023] Fig. 5 shows the cylinder head in a section through an intake port along line VI-VI in Fig. 4; and

[0024] Fig. 6 shows detail VI from Fig. 5. Figs. 1 and 2 each show a core arrangement 1 for a cylinder head 2 of an internal combustion engine with at least one cylinder 20. The core arrangement 1 has at least one one-piece lost core 10, for example a sand core, which forms several core areas 11 for functionally different sections of the cylinder head 2.

[0025] A first core area 11 has at least one first shaped surface 11a for at least one intake port opening into a combustion chamber roof 22 of the cylinder head 2 via at least one intake opening 21a. In the examples shown in Fig. 1 and Fig. 2, the first core area 11 has two first shaped surfaces 11a for two intake ports.

[0026] A second core area 12, designed as a combustion chamber plate, has at least one second shaped surface 12a for forming at least part of a combustion chamber ceiling 22. The second core area 12 further comprises, adjacent to the first core area 11, at least one first chamfered shaped surface 12b for forming a charge-movement-generating area around the inlet opening 21a of the combustion chamber ceiling 22.

[0027] In the example shown, the second mold surface 12a of the second core area 12 of the one-piece lost core 10 forms the entire combustion chamber ceiling 22 of at least one cylinder 20.

[0028] The first chamfered surface 12b of the second core area 12 is formed by a ramp surface around the first core area 11 that is inclined to the second surface 12a - for example, essentially conical.

[0029] A third core area 13 of the one-piece lost core 10 has at least one third molded surface 13a for at least one outlet channel 23. In the examples shown in Fig. 1 and Fig. 2, the first core area has two third molded surfaces 13a for two outlet channels 23.

[0030] The second core area 12 further comprises at least one second chamfered surface 12c for forming an outlet area 22c around each outlet opening 23a. The second chamfered surface 12c is formed around each third core area 13.

[0031] In the second embodiment shown in Fig. 2, the one-piece expendable core 10 is designed with at least a fourth core area 14. The fourth core area 14 has at least a fourth molded surface 14a for at least one coolant channel 24a and / or for at least one lubricant channel 24b. The one-piece expendable core 10 is manufactured, for example, by an additive manufacturing process – preferably a 3D printing process.

[0032] Fig. 3 shows a combustion chamber view of a cylinder head 2 for an internal combustion engine, which is manufactured using the core arrangement 1 shown in Fig. 1. In the illustrated embodiment, the cylinder head 2 has two intake ports 21, two exhaust ports 23, and a combustion chamber ceiling 22 with a substantially flat combustion chamber surface 22a for each cylinder 20. Charge motion-generating areas 22b are formed in the combustion chamber ceiling 22 in the region of the intake openings 21a. The charge motion-generating areas 22b are formed by substantially conical and / or inclined chamfers that surround the intake opening 21 at least partially. The intake ports 21 open into intake openings 21a, and the exhaust ports 23 extend from exhaust openings 23a in the combustion chamber ceiling 22.Reference numeral 22c designates the intake openings 21a surrounding the intake valve seats, and reference numeral 22d designates the exhaust openings 23a surrounding the exhaust valve seats.

[0033] Charge-generating regions 22b are each formed by a first chamfered surface 12b of the second core region 12 of the one-piece lost core 10. Furthermore, outlet regions 22c can each be formed by a second chamfered surface 12c of the second core region 12 of the one-piece lost core 10.

[0034] The charge-generating region 22b is formed, for example, by a first chamfer around an inlet opening 21a, which is inclined to an inlet opening plane E perpendicular to an inlet channel axis 21b in the region of the inlet opening 21a. A first angle of inclination β between the inlet opening plane s and the charge-generating region 22b can be, for example, approximately 10° to 40° (see Fig. 6).

[0035] The charge-generating region 22b extends, for example, around an angular range o of at least 120°, in particular of at least 150°, around the inlet opening 21a, as can be seen in particular from Fig. 4.

[0036] Furthermore, at least one outlet area 22c can be formed by a second chamfer around an outlet opening 21a, which is inclined to an outlet opening plane perpendicular to an outlet channel axis 23b in the region of the outlet opening 23a. Here, too, the second angle of inclination – not further specified – between the outlet opening plane and the area 22c generating a second charge motion can be approximately 10° to 40°. The outlet area 22c is formed circumferentially around the outlet opening 23a. Coolant channels 24a and lubricating oil channels 24b are formed in the cylinder head 20 in the edge region of the cylinder 20. The coolant channels 24a and the lubricating oil channels 24b can be formed by fourth forming surfaces 14a of a fourth core area 14 of the one-piece expendable core 10.

[0037] In the center of cylinder 20, a first dome 25a is provided for receiving an ignition device (not shown). Furthermore, in the area of ​​an intake valve bridge 26 formed between two intake openings 21a, a second dome 25b for receiving an injection device (not further specified) is formed in the cylinder head 20.

[0038] In an embodiment variant not shown further, the first dome 25a and the second dome 25b are formed by further shaped surfaces of the second core area 15 of the one-piece lost core 10.

[0039] The measures described enable an increase in accuracy and a reduction in manufacturing tolerances with low manufacturing effort.

Claims

PATENT CLAIMS 1. Core arrangement (1) for a cylinder head (2) of an internal combustion engine, comprising at least one one-piece lost core (10), in particular a sand core, which has several core areas (11, 12, 13, 14, 15) for functionally different sections of the cylinder head (2), wherein for at least one cylinder (20) a first core area (11) has at least one first shaped surface (11a) for at least one inlet channel (21) opening into a combustion chamber roof (22) of the cylinder head via at least one inlet opening (21a) and a second core area (12) has at least one second shaped surface (12a) for at least a part of a combustion chamber roof (22), characterized in that the second core area (12) has at least one first chamfered shaped surface (12b) for a charge motion generating area (22b) around the inlet opening (21a) of the combustion chamber roof (22).

2. Core arrangement (1) according to claim 1, characterized in that the second forming surface (12a) of the second core area (12) of the one-piece lost core (10) forms the entire combustion chamber ceiling (22) of at least one cylinder (20).

3. Core arrangement (1) according to claim 1 or 2, characterized in that the first chamfered forming surface (12b) of the second core area (12) is arranged adjoining the first core area (11).

4. Core arrangement (1) according to claim 3, characterized in that the first chamfer forming surface (12b) is formed by a ramp surface around the first core area (11) which is inclined to the second forming surface (12a) and is preferably substantially conical.

5. Core arrangement (1) according to claim 3 or 4, characterized in that the first chamfered forming surface (12b) extends around the inlet opening (21a) by an angular range (o) of at least 120°, preferably of at least 150°.

6. Core arrangement (1) according to one of claims 1 to 5, characterized in that the second core area (12) forms at least a second chamfered surface (12c) for a discharge area (22c) around an outlet opening (23a).

7. Core arrangement (1) according to one of claims 1 to 6, characterized in that a third core area (13) of the one-piece lost core (10) has at least a third shaped surface (13a) for at least one outlet channel (23).

8. Core arrangement (1) according to claim 7, characterized in that the second chamfered forming surface (12c) of the second core area (12) is arranged adjoining the third core area (11).

9. Core arrangement (1) according to one of claims 6 to 8, characterized in that the second chamfer forming surface (12c) is formed by a ramp surface around the third core area (11) which is inclined to the second forming surface (12a) and is preferably substantially conical.

10. Core arrangement (1) according to claim 9, characterized in that the second chamfered surface (12c) is formed around the third core area (11).

11. Core arrangement (1) according to one of claims 1 to 10, characterized in that a fourth core area (14) of the one-piece lost core (10) has at least a fourth forming surface (14a) for at least one coolant channel (24a) and / or for one lubricating oil channel (24b).

12. Core arrangement (1) according to one of claims 1 to 11, characterized in that at least one one-piece lost core (10) is manufactured by an additive manufacturing process.

13. Cylinder head (2) which is manufactured with a core arrangement (1) according to one of claims 1 to 12, characterized in that at least one charge movement generating area (22b) is arranged around an inlet opening (21a) in the area of ​​the combustion chamber ceiling (22), which is manufactured by casting and without material removal.

14. Cylinder head (2) according to claim 13, characterized in that at least one charge motion generating area (22b) is formed by a first chamfer around the inlet opening (21a), which is inclined to an inlet opening plane (s) normal to an inlet channel axis (21b) in the area of ​​the inlet opening (21a), wherein preferably a first angle of inclination (β) between the inlet opening plane (s) and the charge motion generating area (22b) is approximately 10° to 40°.

15. Cylinder head (2) according to claim 13 or 14, characterized in that at least one outlet area (22c) is formed by a second chamfer around the outlet opening (21a), which is inclined to a surface normal to an outlet opening. The outlet channel axis (23b) is formed in the area of ​​the outlet opening (23a) in the outlet opening plane, wherein preferably a second angle of inclination between the outlet opening plane and the outlet area (22c) is approximately 10° to 40°.

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