Liquid-cooled cylinder head

Abstract

The invention relates to a liquid-cooled cylinder head (1) for an internal combustion engine with a top-down cooling concept, having a lower cooling chamber (4) adjoining a fire deck (3) and an upper cooling chamber (5) which is separated from the lower cooling chamber (4) by an intermediate deck (6) and which is largely further away from the fire deck (3) than the lower cooling chamber (4), wherein the lower cooling chamber (4) and the upper cooling chamber (5) are connected fluidically together in the region of a receiving sleeve (8), arranged centrally with respect to the cylinder (2), for a component (80) leading centrally into a combustion chamber (7), via at least one annular overflow channel (9), formed by an overflow opening (14) and the receiving sleeve (8), in the intermediate deck (6), wherein a diameter (D) of the substantially circular overflow opening (14) is larger than an outside diameter (d) of the receiving sleeve (8), having an inlet channel arrangement with at least two inlet openings (10E) leading into the combustion chamber (7) and an outlet channel arrangement with at least two outlet openings (10A) leading into the combustion chamber (7). In order to achieve optimal cooling of thermally critical regions, the invention provides that the overflow opening (14) is arranged eccentrically with respect to the receiving sleeve (8), wherein a central axis (14a) of the overflow opening (14), extending through a center (M) of the overflow opening (14), is spaced apart from the sleeve axis (8a) of the receiving sleeve (8).

Description

[0001] Liquid-cooled cylinder head

[0002] The invention relates to a liquid-cooled cylinder head for an internal combustion engine with a top-down cooling concept, in particular with several cylinders, with a lower cooling chamber bordering a fire deck and an upper cooling chamber, which is separated from the lower cooling chamber by an intermediate deck and which is predominantly further away from the fire deck than the lower cooling chamber, wherein the lower cooling chamber and the upper cooling chamber are fluidly connected to one another in the region of a receiving sleeve arranged centrally with respect to the cylinder - preferably concentrically or parallel to the cylinder axis - for a component opening centrally into a combustion chamber via at least one annular overflow channel in the intermediate deck formed by an overflow opening and the receiving sleeve, wherein a diameter of the substantially circular overflow opening is larger than an outer diameter of the receiving sleeve,with an inlet channel arrangement with at least two inlet openings opening into the combustion chamber and an outlet channel arrangement with at least two outlet openings opening into the combustion chamber.,

[0003] A top-down cooling concept is a cooling concept in which the coolant first flows through the upper cooling chamber further away from the fire deck and then through the lower cooling chamber closer to the fire deck.

[0004] WO 2020 / 188071 A1 discloses a cylinder head for an internal combustion engine with a top-down cooling system, which comprises an upper cooling chamber adjacent to an intermediate deck and a lower cooling chamber adjacent to a fire deck. In the area of ​​a central receiving sleeve for an injection or ignition device, an annular transfer opening is provided between the upper and lower cooling chambers. The transfer opening is concentric with the receiving sleeve.

[0005] DE 103 50 394 A1 describes a cylinder head for a liquid-cooled multi-cylinder internal combustion engine with a cooling chamber arrangement adjacent to a fire deck, which is divided by an intermediate deck into a lower partial cooling chamber and an upper partial cooling chamber. The two partial cooling chambers are fluidly connected to one another by overflow openings in the region of a receiving opening for a sleeve for a central fuel injection device, which overflow openings are designed as bulges in the receiving opening. Similar cooling arrangements are known from EP 2998 555 A1, EP 3 333 398 A1, or WO 2012 / 004340 A1. The object of the invention is to achieve optimal cooling of thermally critical areas of the cylinder head in a simple manufacturing manner.

[0006] According to the invention, this is achieved in an internal combustion engine of the type mentioned at the outset in that the overflow opening is arranged eccentrically with respect to the receiving sleeve, wherein a central axis of the overflow opening running through a center point of the overflow opening is spaced from the sleeve axis of the receiving sleeve, wherein preferably the central axis of the overflow opening and the sleeve axis are arranged parallel to one another.

[0007] Preferably, the distance between the sleeve axis and the center axis of the overflow opening is less than half the outer diameter of the receiving sleeve.

[0008] To achieve optimal cooling, it is advantageous if the center axis of the transfer port is located on the exhaust side and / or is positioned closer to an exhaust valve bridge between two exhaust ports than to an intake valve bridge between two intake ports. In other words, the eccentric transfer port is oriented toward the exhaust valve bridge between the two exhaust valves.

[0009] The overflow opening can be formed by casting and / or machining of the intermediate deck.

[0010] The eccentrically designed overflow opening creates a transfer channel with an eccentric overflow cross-section that is larger on the exhaust side than on the inlet side. This allows for improved cooling even with small coolant quantities.

[0011] In one embodiment of the invention, the intermediate deck has at least one local intermediate deck elevation, preferably produced by casting, in the region of the transfer opening. In this way, the cooling section is extended in the direction of the cylinder axis and thus the cooling water flow towards the fire deck is improved. Furthermore, the intermediate deck elevation can increase the structural rigidity by connecting a vertical support structure of the cylinder head to the intermediate deck. The vertical support structure connects the oil deck to the fire deck in the vertical direction within the cylinder head. The vertical support structure extends between the valve guides and / or those of the inlet and outlet openings and the transfer opening. A similar support structure is known, for example, from AT 522 060 B1. Advantageously, the intermediate deck elevation is annular and arranged concentrically around the transfer opening.Advantageously, the intermediate deck elevation can be arranged between the intake and exhaust ports and the transfer port. The intermediate deck elevation thus forms a ring around the receiving sleeve between the intake and exhaust ports and the transfer port and is integrated into the vertical support structure of the cylinder head.

[0012] In order to reduce the losses during the flow transfer between the two cooling rooms, it is advantageous if at least one intermediate deck elevation has an inlet bevel on an inner side adjacent to the overflow opening in the region of an upper side facing away from the intermediate deck.

[0013] In a further embodiment of the invention, the overflow opening has at least one bulge, wherein the bulge is preferably located in the region of a valve bridge. A bulge is understood here as an outwardly extending cross-sectional area deviating from the circular shape of the overflow opening. This makes it possible to increase the flow of the coolant flowing between the upper cooling chamber and the lower cooling chamber, thus improving heat dissipation.

[0014] The entire transition cross-section for the coolant transfer between the upper cooling chamber and the lower cooling chamber results from a combination of machined and cast transitions in the area of ​​the receiving sleeve, i.e. through the circular eccentric transfer opening and the additional bulges.

[0015] The invention is explained in more detail below with reference to the non-limiting embodiments shown in the figures.

[0016] Fig. 1 shows a cylinder head according to the invention in a first embodiment variant in a section along the line II in Fig. 2;

[0017] Fig. 2 this cylinder head in a section along the line II-II in Fig. 1; and

[0018] Fig. 3 shows the cylinder head in a second embodiment in a section analogous to Fig. 2.

[0019] Figures 1 and 2 show a cylinder head 1 for an internal combustion engine with one or more cylinders 2. The cylinder head 1 has a lower cooling chamber 4 adjacent to a fire deck 3 and an upper cooling chamber 5 spaced from the fire deck 3 and separated from the lower cooling chamber 4 by an intermediate deck 6. The terms "bottom" and "top" refer to the illustration shown in Fig. 1 and not to the actual installation position of the internal combustion engine during operation. The actual installation position of the cylinder head 1 may therefore deviate from the orientation shown in Fig. 1.

[0020] The upper cooling chamber 5 is predominantly further away from the fire deck 3 than the lower cooling chamber 4. The lower cooling chamber 4 and the upper cooling chamber 5 are fluidly connected to one another in the region of a receiving sleeve 8, which is arranged centrally with respect to the cylinder 2, for example concentrically and parallel to the cylinder axis 2a, for a component 80 opening centrally into a combustion chamber 7, such as an injection device or an ignition device, via at least one overflow channel 9 in the intermediate deck 6. The cylinder head 1 has two inlet openings 10E opening into the combustion chamber 7 for an inlet channel arrangement (not shown in more detail) on an inlet side E of the cylinder head 1 and two outlet openings 10A opening into the combustion chamber 7 for an exhaust channel arrangement (not shown in more detail) on an outlet side A of the cylinder head 1.

[0021] Inlet valve bridges 11 are formed between the inlet openings 10E, and outlet valve bridges 12 are formed between the outlet openings 10A. An inlet / outlet valve bridge 13 is located between each inlet opening 9 and each outlet opening 10. The lower cooling chamber 4 has a bridge channel 41, 42, 43 in the area of ​​the inlet valve bridge 11, in the area of ​​the outlet bridge 12, and in the area of ​​the inlet / outlet valve bridges 13. The bridge channels 41, 42, 43 are indicated by dashed lines in Fig. 2.

[0022] The overflow channel 9 between the upper cooling chamber 5 and the lower cooling chamber 4 is oriented essentially in the direction of the cylinder axis 2a. It is formed by a substantially circular overflow opening 14 arranged in the intermediate deck 6 and the, for example, cylindrical outer surface 8b of the receiving sleeve 8. The overflow opening 14 can be cast into the cylinder head 1 and / or formed by machining the intermediate deck 6.

[0023] The overflow opening 14 of the overflow channel 9 is arranged eccentrically with respect to the sleeve axis 8a of the receiving sleeve 8. The overflow channel 9 has a substantially annular, eccentric cross-section. The diameter D of the overflow opening 14 is larger than the outer diameter d of the receiving sleeve 8. A central axis 14a of the overflow opening 14, which runs through the center point M of the circular overflow opening 14, is spaced from the sleeve axis 8a of the receiving sleeve 8. The central axis 14a of the overflow opening 14 and the sleeve axis 8a are, for example, arranged substantially parallel to one another. The central axis 14a of the overflow opening 14 is arranged on the outlet side A. In other words, the central axis 14a is arranged closer to the outlet valve bridge 12 between the two outlet openings 10A than to the inlet valve bridge 11 between the two inlet openings 10E.The distance a between the sleeve axis 8a and the central axis 14a is less than half the outer diameter d of the receiving sleeve 8, in particular less than a quarter of the outer diameter d of the receiving sleeve 8. The eccentrically arranged overflow opening 14 results in an eccentrically shaped overflow channel 9 which has a larger cross-section on the outlet side A than on the inlet side E (see Fig. 2).

[0024] Furthermore, at least one intermediate deck elevation 16, produced, for example, by casting, can be arranged between an inlet opening 10E and / or an outlet opening 10A and the overflow opening 14. Fig. 1 and Fig. 2 show an embodiment in which an intermediate deck elevation 16 arranged annularly and concentrically around the overflow opening 14 and the receiving sleeve 8 is provided between the outlet openings 10A or inlet openings 10E and the overflow opening 14. The position of the intermediate deck elevation 16 is indicated by dashed lines in Fig. 2. The intermediate deck elevation 16 connects a vertical support structure 18 of the cylinder head 1 to the intermediate deck 6. This can increase the structural rigidity of the cylinder head 1.The vertical support structure 18 connects the oil deck 19 to the fire deck 4 in the vertical direction within the cylinder head 1 and extends between the valve guides and / or those of the inlet 10E and outlet openings 10A and the transfer opening 14.

[0025] As can be seen from Fig. 1, the intermediate deck elevation 16 in the exemplary embodiment has an inlet bevel 17 on an inner side bordering the overflow opening 14 in the region of an upper side facing away from the intermediate deck 6 in order to minimize the flow losses during the flow transfer between the upper cooling space 5 and the lower cooling space 4.

[0026] The intermediate deck elevations 16 extend the cooling section in the direction of the cylinder axis 2a and improve the cooling water flow toward the fire deck 4. Furthermore, the intermediate deck elevation 16 increases the structural rigidity.

[0027] The overflow opening 14 can have at least one bulge 15 in the region of a valve bridge, for example, the outlet valve bridge 12, in order to increase the flow of the coolant flowing between the upper cooling chamber 5 and the lower cooling chamber 4 and thus improve heat dissipation. The bulge 15 is indicated by dashed lines in Fig. 3. The intermediate deck elevation and vertical support structure are not shown in Fig. 3.

[0028] Cylinder head 1 features a so-called top-down cooling concept. A top-down cooling concept refers to a cooling system in which the coolant first flows through the upper cooling chamber 5, which is farther from the fire deck, and then through the lower cooling chamber 4, which is closer to the fire deck.

[0029] The coolant flows in the cylinder head 2 according to the arrows P in the upper cooling chamber 5 radially towards the receiving sleeve 8 and reaches the lower cooling chamber 4 via the eccentrically designed overflow channel 9. The receiving sleeve 8 and the component 80 received by the receiving sleeve 8 are cooled in the process. The coolant flows radially outwards through the bridge channels 41, 42, 43 of the lower cooling chamber 4, cooling the thermally critical areas of the exhaust valve bridge 12, as well as the intake valve bridge 11 and the intake / exhaust valve bridges 13 (Fig. 1). Due to the eccentric shape of the overflow channel 9, considerably more coolant flows on the exhaust side A through the overflow channel 9 from the upper cooling chamber 5 into the lower cooling chamber 4 than on the intake side E.

Claims

PATENT CLAIMS Liquid-cooled cylinder head (1) for an internal combustion engine with a top-down cooling concept, in particular with several cylinders (2), with a lower cooling chamber (4) bordering a fire deck (3) and an upper cooling chamber (5), which is separated from the lower cooling chamber (4) by an intermediate deck (6) and which is predominantly further away from the fire deck (3) than the lower cooling chamber (4), wherein the lower cooling chamber (4) and the upper cooling chamber (5) are fluidly connected to one another in the region of a receiving sleeve (8) arranged centrally with respect to the cylinder (2) - preferably concentrically or parallel to the cylinder axis (2a) - for a component (8) opening centrally into a combustion chamber (7) via at least one annular overflow channel (9) in the intermediate deck (6) formed by an overflow opening (14) and the receiving sleeve (8),wherein a diameter (D) of the substantially circular overflow opening (14) is larger than an outer diameter (d) of the receiving sleeve (8), with an inlet channel arrangement with at least two inlet openings (10E) opening into the combustion chamber (7) and an outlet channel arrangement with at least two outlet openings (10A) opening into the combustion chamber (7), characterized in that the overflow opening (14) is arranged eccentrically with respect to the receiving sleeve (8), wherein a central axis (14a) of the overflow opening (14) extending through a center point (M) of the overflow opening (14) is spaced from the sleeve axis (8a) of the receiving sleeve (8), wherein preferably the central axis (14a) of the overflow opening (14) and the sleeve axis (8a) are arranged parallel to one another. Cylinder head (1) according to claim 1, characterized inthat the distance (a) between the sleeve axis (8a) and the central axis (14a) of the overflow opening (14) is less than half the outer diameter (d) of the receiving sleeve (8), preferably less than a quarter of half the outer diameter (d) of the receiving sleeve (8). Cylinder head (1) according to claim 1 or 2, characterized in that the overflow opening (14) of the overflow channel (9) is formed by machining the intermediate deck (6). Cylinder head (1) according to one of claims 1 to 3, characterized in that the intermediate deck (6) has at least one intermediate deck elevation (16) in the region of the overflow opening (14). Cylinder head (1) according to claim 4, characterized in that the intermediate deck elevation (16), preferably produced by casting, is between, Inlet openings (10E), outlet openings (10A) and the overflow opening (14). Cylinder head (1) according to claim 4 or 5, characterized in that the intermediate deck elevation is annular and arranged concentrically around the overflow opening (14). Cylinder head (1) according to one of claims 4 to 6, characterized in that the intermediate deck elevation (16) has an inlet chamfer (17) on an inner side bordering the overflow opening (14) in the region of an upper side facing away from the intermediate deck (6). Cylinder head (1) according to one of claims 4 to 7, characterized in that the intermediate deck elevation (16) connects a vertical support structure (18) of the cylinder head (1) to the intermediate deck (6).Cylinder head (1) according to one of claims 1 to 8, characterized in that the central axis (14a) of the overflow opening (14) is arranged on the exhaust side (A) and / or is arranged closer to an exhaust valve bridge (12) between two exhaust openings (10A) than to an intake valve bridge (11) between two intake openings (10E). Cylinder head (1) according to one of claims 1 to 9, characterized in that the overflow opening (14) has at least one bulge (15), wherein the bulge (15) is preferably arranged in the region of an exhaust valve bridge (12).

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