Internal combustion engine
The internal combustion engine's receiving sleeve with overflow channels and radial partitions addresses thermal inefficiencies by enhancing coolant flow control and heat dissipation, improving thermal management and combustion efficiency.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- AVL LIST GMBH
- Filing Date
- 2025-12-05
- Publication Date
- 2026-06-11
AI Technical Summary
Existing cooling systems for internal combustion engines, particularly around mounting bosses for components like spark plugs, suffer from thermal inefficiencies due to uncontrolled coolant flow and turbulence, making it difficult to manage high temperatures effectively.
The receiving sleeve in the cylinder head features overflow channels with radial partitions and a double-walled design, along with longitudinal ribs to align coolant flow, ensuring controlled and efficient heat dissipation through channels with defined cross-sections and orientations.
This design enhances thermal management by reducing turbulence and improving heat dissipation, particularly around critical areas such as spark plug threads, optimizing combustion efficiency and temperature control.
Smart Images
Figure AT2025060450_11062026_PF_FP_ABST
Abstract
Description
[0001]
[0002] internal combustion engine
[0003] The invention relates to an internal combustion engine, in particular a hydrogen-powered internal combustion engine, with at least one cylinder, with a cylinder head having at least one upper partial cooling chamber and at least one lower partial cooling chamber, which are separated from each other by an intermediate deck, with at least one receiving sleeve penetrating the intermediate deck for receiving a component opening into a combustion chamber, in particular a spark plug, wherein the receiving sleeve is firmly anchored in the cylinder head, wherein at least one transfer channel is arranged in the area of the receiving sleeve between the two partial cooling chambers to allow the coolant to flow from one partial cooling chamber to the other partial cooling chamber.
[0004] Mounting sleeves are used for installing components such as injectors or spark plugs through coolant-carrying areas in the cylinder head. These allow for controlled coolant flow and a dry area for receiving the component.
[0005] To keep the high temperatures in the cylinder head within a range tolerable for the material, it is common practice to cool the cylinder head via cooling chambers. For this purpose, the coolant is designed to flow through the cylinder head either from the lower second cooling chamber, coming from the crankcase, to the upper first cooling chamber, or from the upper first cooling chamber to the lower second cooling chamber, which is also known as top-down cooling.
[0006] Such arrangements are known, for example, from AT 510 857 Bl. This shows a transfer opening around a mounting boss for a spark plug or an injector, extending into the combustion chamber. The transfer opening is defined by the contour of the intermediate deck and limited by manufacturing possibilities. In particular, post-processing of the intermediate deck after casting is not easily possible. This makes cooling thermally critical areas, especially around the mounting boss, difficult. The airflow and cooling of the mounting boss depend on the geometry of the opening in the intermediate deck.
[0007] A similar cylinder head is also known from DE 10 2005 031 243 B4. This patent shows a cooling insert around a component that can represent an injector or a spark plug. This insert is designed to simply surround the actual component or its mounting sleeve. The component is held by a cast boss of the cylinder head. The cooling insert is double-walled, and its outer walls essentially form a hollow cylinder around the component. The interior of this insert is also hollow. The coolant flows from the upper cooling chamber through windows in the outer wall of the cooling insert into the interior of the insert and towards the lower cooling chamber. The coolant then flows back out of the cooling insert into the lower cooling chamber through windows in the outer wall.The flow connection between the upper and lower cooling chambers is formed by the cavity between the outer and inner walls. A disadvantage of this design is that the flow exhibits undesirable turbulence, as the flow within the cavity cannot be precisely controlled without additional means.
[0008] From AT 521 514 Bl, a cylinder head for an internal combustion engine is known, wherein a sleeve for receiving a spark plug is arranged in the region of the cylinder axis of a cylinder of the cylinder head. The sleeve has recesses formed by longitudinal grooves and open towards the valve bridges, which form flow connections between an upper and a lower partial cooling chamber of the cylinder head.
[0009] The object of the present invention is to improve the cooling of thermally critical areas of the receiving sleeve.
[0010] According to the invention, this problem is solved in an internal combustion engine of the type mentioned at the outset by the fact that the receiving sleeve has an overflow area at least in the area of the intermediate deck, wherein at least one first overflow channel extending substantially in the direction of a fictitious axis of rotation of the receiving sleeve is arranged in the overflow area between an inner wall area and an outer wall area of the receiving sleeve, wherein preferably several first overflow channels are arranged uniformly distributed in the circumferential direction in the overflow area.
[0011] To achieve effective cooling, it is advantageous to arrange at least two radial partitions in the overflow area between the inner and outer wall regions of the receiving sleeve, preferably with the radial partitions arranged uniformly around the circumference within the overflow area. The radial partitions prevent turbulence and ensure a flow between the cooling chambers that is essentially directed along the axis of rotation.
[0012] It is advantageous that at least one of the first transfer channels has a closed-profile cross-section. To achieve good cooling in the transfer area, it is beneficial if at least one of the first transfer channels has a substantially trapezoidal cross-section. However, the cross-section of the first transfer channel can also be rectangular, triangular, round, or oval.
[0013] One embodiment of the invention provides that the overflow area is formed by or has a bead-like thickening of the receiving sleeve. The first overflow channels are formed into the bead-like thickening.
[0014] Alternatively or additionally, the receiving sleeve can be designed as essentially double-walled in the overflow area, with the outer wall area preferably being formed by a circumferential ring area concentric to the fictitious axis of rotation. The ring area is connected to the inner wall area of the receiving sleeve via the spoke-like intermediate walls.
[0015] To improve heat dissipation, particularly in the area of the component's thread – for example, the spark plug thread – it is advantageous if at least one transfer channel – preferably all first transfer channels – each between a first channel end and a second channel end – viewed in a longitudinal section of the receiving sleeve – is essentially shaped as an arc, with a convex outer side of the arc formed by the inner wall region and a concave inner side of the arc formed by the outer wall region of the receiving sleeve. The arc shape brings the first transfer channels close to the inner side of the sleeve, thus enabling excellent heat dissipation from the thread area.
[0016] In a manufacturing-technically simple embodiment of the invention, the receiving sleeve is formed in one piece. Preferably, the receiving sleeve is manufactured by a casting process, an additive manufacturing process, or a subtractive manufacturing process.
[0017] To avoid turbulence at the inlet to and / or outlet of the at least one first transfer channel, it is advantageous if the receiving sleeve adjacent to the double-walled transfer area has at least one longitudinal rib, formed substantially parallel to the fictitious axis of rotation, in the region of its outer surface, wherein preferably a plurality of longitudinal ribs are arranged evenly distributed around the circumference of the outer surface. Preferably, at least one longitudinal rib—more preferably a group of longitudinal ribs—is arranged on a side of the transfer area facing the combustion chamber and / or on a side of the transfer area facing away from the combustion chamber. It is particularly advantageous if at least one longitudinal rib is designed as an extension of an intermediate wall.
[0018] The longitudinal ribs align the flow axially before it enters or after it exits the first overflow channels, thus preventing turbulence.
[0019] In a further development of the invention, it is provided that at least one - preferably at least partially annular - second overflow channel is formed between the intermediate deck and the outer wall area.
[0020] The invention is particularly suitable for top-down cooling systems. However, it can also be advantageously applied to conventional cooling systems where the coolant flows from bottom to top.
[0021] Optimal combustion with good heat dissipation can be achieved if at least one receiving sleeve is located in the area of a cylinder axis of a cylinder.
[0022] The invention will be explained in more detail below with reference to the non-limiting embodiments shown in the figures. These schematically depict:
[0023] Fig. 1 shows an internal combustion engine according to the invention in an axonometric representation;
[0024] Fig. 2 shows a cylinder head of this internal combustion engine in a longitudinal section along line II-II in Fig. 3;
[0025] Fig. 3 shows the cylinder head in a section along line III-III in Fig. 2; and
[0026] Fig. 4 shows a receiving sleeve in a first embodiment of the invention in an axonometric representation; and
[0027] Fig. 5 shows a receiving sleeve in a second embodiment of the invention in an axonometric representation.
[0028] Fig. 1 shows an internal combustion engine 1 with a crankcase 2 containing several cylinders 3, in each cylinder 3 having a reciprocating piston 4 which acts on a crankshaft via a connecting rod. For clarity, the connecting rods and crankshaft are not shown in detail. The crankcase 2 is rigidly connected to a cylinder head 5. For each cylinder 3, a combustion chamber 8 is formed between the piston 4 and a combustion chamber cover surface 7 formed by a fire deck 6 of the cylinder head 5.
[0029] Fig. 2 shows the cylinder head 5 and a one-piece receiving sleeve 9 attached to the cylinder head 5 in the region of the cylinder axis 3a. This sleeve has a cavity 98 for receiving a component (not shown) projecting into the combustion chamber 8, such as a spark plug or an injector. The receiving sleeve 9 is essentially rotationally symmetrical with respect to a fictitious axis of rotation 9a, which here coincides with the cylinder axis 3a. The one-piece receiving sleeve 9 can be manufactured, for example, by a casting process, an additive manufacturing process, or a subtractive manufacturing process.
[0030] The cylinder head 5 has an upper partial cooling compartment 10 and a lower partial cooling compartment 11 adjacent to the fire deck 6, the upper partial cooling compartment 10 being further away from the fire deck 6 than the lower partial cooling compartment 11.
[0031] The terms "upper" and "lower" are used only to distinguish the partial cooling spaces 10, 11 and do not imply any restriction or preference on a particular installation position of the internal combustion engine 1.
[0032] The upper cooling compartment 10 is separated from the lower cooling compartment 11 by an intermediate deck 12 of the cylinder head 5. The intermediate deck 12 has, for example, a circular opening 13, which is designed to accommodate the receiving sleeve 9 with clearance. The receiving sleeve 9 is inserted into the opening 13 and thus penetrates the intermediate deck 12. The receiving sleeve 9 is firmly anchored, for example, by means of a thread (not shown) in the fire deck 6 of the cylinder head 5.
[0033] The upper cooling chamber 10 is connected to the lower cooling chamber 11 via at least one flow path 14, which allows coolant to flow from one cooling chamber 10; 11 to the other cooling chamber 11; 10. In a top-down cooling concept, the coolant flows – according to the arrows S in Fig. 2 – via the flow path 14, for example, from the upper cooling chamber 10 to the lower cooling chamber 11. The flow path 14 is formed by overflow channels 15, 16 in the area of the receiving sleeve 9.
[0034] The receiving sleeve 9 has an overflow area 17 in the area of the intermediate deck 12.
[0035] In the overflow area 17, several first overflow channels 15 are arranged between an inner wall region 92 and an outer wall region 93 of the receiving sleeve 9, extending essentially in the direction of a fictitious axis of rotation 9a of the receiving sleeve 9 (see Fig. 2). In the illustrated embodiment, the first overflow channels 15 are arranged uniformly in the circumferential direction between the inner wall region 92 and the outer wall region 93 of the receiving sleeve 9. Radial partitions 94 are arranged uniformly in the circumferential direction between the inner wall region 92 and the outer wall region 93 of the receiving sleeve 9, as can be seen in Fig. 3. A radial partition 94 is arranged between each pair of adjacent first overflow channels 15. Valve bridges 19 arranged between two gas exchange valves 18 are indicated by dashed lines in Fig. 3.
[0036] The overflow area 17 is formed by or has a circumferential bead-like thickening 90 of the receiving sleeve 9. The first overflow channels 15 are formed into the bead-like thickening 90.
[0037] The receiving sleeve 9 is essentially double-walled in the overflow area 17. The outer wall area 93 is formed by a circumferential ring area 91 concentric to the fictitious axis of rotation 9a. The ring area 91 is connected to the inner wall area 92 of the receiving sleeve 9 via the spoke-like intermediate walls 94.
[0038] The first overflow channels 15 have a closed profile cross-section within the receiving sleeve 9. In the illustrated embodiment, the profiles or cross-sections of the first overflow channels 15 are, for example, trapezoidal, as can be clearly seen in Fig. 3. Alternatively, the profiles or cross-sections of the first overflow channels 15 can also be triangular, rectangular, circular, elliptical, or oval.
[0039] The first overflow channels 15 are each formed between a first channel end 151 and a second channel end 152 – viewed in a longitudinal section of the receiving sleeve 9 – essentially as an arc 153. A convex outer surface of the arc 153 is formed by the inner wall region 92 and a concave inner surface of the arc 153 by the outer wall region 93 of the receiving sleeve 9. The annular region 91 extends between the first channel ends 151 and the second channel ends 152. In other words, the first channel ends 151 and the second channel ends 152 are located at opposite end faces of the annular region 91.
[0040] A first overflow channel 15 shaped as an arc 153 is understood here to be a first overflow channel 15 designed in a C- or U-shape, which has a change of direction in at least one plane between the two channel ends 151, 152. The change of direction can be achieved by a curved channel design or – as shown in Fig. 2 – by an angled channel design. In the exemplary embodiment, the angle θ of the change of direction between a flow axis at the first channel end 151 and a flow axis at the second channel end 152 of each first overflow channel 15 is approximately 90° to 120°.
[0041] As shown in Figs. 2 and 3, at least one second transfer channel 16 can be provided between the outer wall area 93 and the intermediate deck 12, which connects the upper partial cooling compartment 10 with the lower partial cooling compartment 11. The second transfer channel 16 is, for example, annular in shape and formed by an annular gap between the circumferential ring area 91 and the opening 13 in the intermediate deck 12.
[0042] Fig. 4 shows a receiving sleeve 9 with a transfer area 17, which has a circumferential bead-like thickening 90 with a cylindrical ring section 91. On an end face facing away from the combustion chamber 8, the receiving sleeve 9 has a cylindrical collar 99 with a diameter D, which is larger than the diameter d of a cylindrical surface 95 adjoining the collar 99. The bead-like thickening 90 has a diameter D1, which is also larger than the diameter d of the axially adjacent cylindrical surface 95 and here corresponds at most substantially to the diameter D of the collar 99 or is smaller than the diameter D of the collar 99. Within the bead-like thickening 90, the first transfer channels 15 run between a first channel end 151 and a second channel end 152. The first channel ends 151 are designed to be flow-connected to the first partial cooling chamber 10.The second channel ends 152 are designed to be flow-connected to the second partial cooling chamber 10.
[0043] The receiving sleeve 9 shown in Fig. 5 differs from that in Fig. 4 in that a number of longitudinal ribs 96, 97, arranged parallel to the fictitious axis of rotation 9a, are provided adjacent to the overflow area 17 in the region of the outer surface 95. The longitudinal ribs 96, 97 are arranged evenly distributed around the circumference of the outer surface 95 and extend from the intermediate walls 94.
[0044] In this case, a group of longitudinal ribs 96 is arranged in the area of the upper partial cooling chamber 10 on a side of the transfer area 17 facing away from the combustion chamber 8 and / or a group of longitudinal ribs 97 is arranged in the area of the lower partial cooling chamber 11 on a side of the transfer area 17 facing the combustion chamber 8.
[0045] The invention is suitable for all externally spark-ignited internal combustion engines 1, but is particularly well suited for hydrogen-powered internal combustion engines 1.
Claims
P A T E N T A N S P R Ü C H E 1. Internal combustion engine (1), in particular a hydrogen-powered internal combustion engine (1), with at least one cylinder (3), with a cylinder head (5) having at least one upper partial cooling chamber (10) and at least one lower partial cooling chamber (11) separated from each other by an intermediate deck (12), with at least one receiving sleeve (9) penetrating the intermediate deck (12) for receiving a component opening into a combustion chamber (8), in particular a spark plug, wherein the receiving sleeve (9) is firmly anchored in the cylinder head (5), wherein at least one transfer channel (15, 16) is arranged in the area of the receiving sleeve (9) between the two partial cooling chambers (10, 11) to allow the coolant to flow from one partial cooling chamber (10; 11) into the other partial cooling chamber (11;10) to flow, characterized in that the receiving sleeve (9) has an overflow area (17) at least in the area of the intermediate deck (12), wherein in the overflow area (17) between an inner wall area (92) and an outer wall area (93) of the receiving sleeve (9) at least one first overflow channel (10) extending substantially in the direction of a fictitious axis of rotation (9a) of the receiving sleeve (9) is arranged, wherein preferably several first overflow channels (10) are arranged uniformly distributed in the circumferential direction in the overflow area (17).
2. Internal combustion engine (1) according to claim 1, characterized in that at least two radial intermediate walls (94) are arranged in the overflow area (17) between the inner wall area (92) and the outer wall area (93) of the receiving sleeve (9), wherein preferably the radial intermediate walls (94) are arranged uniformly distributed in the circumferential direction in the overflow area (17).
3. Internal combustion engine (1) according to claim 1 or 2, characterized in that at least a first overflow channel (15) has a cross-section with a closed profile.
4. Internal combustion engine (1) according to one of claims 1 to 3, characterized in that at least a first overflow channel (15) has a substantially trapezoidal, rectangular triangular, round or oval cross-section.
5. Internal combustion engine (1) according to one of claims 1 to 4, characterized in that the overflow area (17) is formed by a bead-like thickening (90) of the receiving sleeve (9) or has a bead-like thickening (90).
6. Internal combustion engine (1) according to one of claims 1 to 5, characterized in that the receiving sleeve (9) in the overflow area (17) is essentially double-walled, wherein preferably the outer wall area (93) is formed by a circumferential - preferably cylindrical - ring area (91) formed concentrically to the fictitious axis of rotation (9a).
7. Internal combustion engine (1) according to one of claims 1 to 6, characterized in that at least one first transfer channel (15) - preferably all first transfer channels (15) - each between a first channel end (151) and a second channel end (152) - viewed in a longitudinal section of the receiving sleeve (9) - is / are essentially formed as an arc (153), wherein a convex outer side of the arc (153) is formed by the inner wall region (92) and a concave inner side of the arc (153) is formed by the outer wall region (93) of the receiving sleeve (9).
8. Internal combustion engine (1) according to one of claims 1 to 7, characterized in that the receiving sleeve (9) is formed in one piece.
9. Internal combustion engine (1) according to one of claims 1 to 8, characterized in that the receiving sleeve (9) is manufactured by a casting process or an additive manufacturing process or a subtractive manufacturing process.
10. Internal combustion engine (1) according to one of claims 1 to 9, characterized in that the receiving sleeve (9) has at least one longitudinal rib (96, 97) formed substantially parallel to the fictitious axis of rotation (9a) in the area of its outer surface (95) adjacent to the overflow area (17), wherein preferably a plurality of longitudinal ribs (96, 97) are arranged evenly distributed around the circumference of the outer surface (95).
11. Internal combustion engine (1) according to claim 10, characterized in that at least one longitudinal rib (96, 97) - preferably a group of longitudinal ribs (96, 97) - is arranged on a side of the transfer area (17) facing away from the combustion chamber (8) and / or on a side of the transfer area (17) facing the combustion chamber (8).
12. Internal combustion engine (1) according to claim 10 or 11, characterized in that at least one longitudinal rib (96, 97) is designed as an extension of an intermediate wall (94).
13. Internal combustion engine (1) according to one of claims 1 to 12, characterized in that at least one - preferably at least partially annular - second overflow channel (16) is formed between the intermediate deck (12) and the outer wall area (93).
14. Internal combustion engine (1) according to one of claims 1 to 13, characterized in that the internal combustion engine (1) has a top-down cooling system.
15. Internal combustion engine (1) according to one of claims 1 to 14, characterized in that at least one receiving sleeve (9) is arranged in the area of a cylinder axis (3a) of a cylinder (3). 2025 12 05 FU / IV