LIQUID-COOLED ENGINE

Description

[0001] The invention relates to a liquid-cooled internal combustion engine, in particular a large engine, with an inlet side and an outlet side arranged on different sides of a longitudinal engine plane spanned by a cylinder axis and a crankshaft axis, with a cylinder head having a top-down cooling concept, comprising a fire deck adjoining a cylinder block and a head cooling chamber with a first head cooling chamber spaced apart from the fire deck and a second head cooling chamber adjoining the fire deck of the cylinder head, which is separated from the first head cooling chamber by an intermediate deck, wherein the first head cooling chamber and the second head cooling chamber are fluidically connected to each other at least in the area of ​​a central component via at least one transfer channel in the intermediate deck, with a main inlet channel arranged in the cylinder block.which is connected to the first cylinder head cooling chamber via a first flow transfer in the fire deck of the cylinder head and a supply channel, with at least one block cooling jacket flow-connected to the second cylinder head cooling chamber via at least a second flow transfer in the fire deck of the cylinder head.

[0002] The invention also relates to a method for cooling such an internal combustion engine.

[0003] From AT 515 143 B1 and AT 503 182 A2, a liquid-cooled internal combustion engine with a cylinder head and a cylinder block is known, wherein the cylinder head has two superimposed partial cooling chambers through which coolant flows according to a so-called top-down cooling concept. The two partial cooling chambers are separated from each other by an intermediate deck and are flow-connected to each other in the area of ​​a centrally located injector sleeve via at least one transfer channel. The coolant is supplied via an inlet channel in the cylinder block, flows through a cooling chamber surrounding the cylinder in the cylinder block, and is supplied directly to the upper partial cooling chamber of the cylinder head via flow transfers in the fire deck and supply channels.This allows the coolant to flow through the cylinder head from top to bottom, with the coolant first being supplied to the upper part of the cooling chamber and, after flowing through the upper part of the cooling chamber, flowing via at least one transfer channel into the lower part of the cooling chamber, where the coolant is guided radially from the inside to the outside via radial cooling channels in the area of ​​the valve bridges and finally leaves the cylinder head again via laterally arranged drain channels.

[0004] AT 005 039 U1 describes a cylinder block for a liquid-cooled internal combustion engine with a distribution channel and a collection channel for coolant, wherein the distribution channel is arranged above the collection channel in the region of a side wall of the cylinder block and the distribution channel is fluidically connected to a first cooling chamber via a feed channel. A cylinder head connection surface of the cylinder block has, for each cylinder, at least one transfer port leading from the first cooling chamber to the cylinder head via a transfer port and at least one outlet port for coolant from the cylinder head leading to the collection channel, wherein the transfer port and the outlet port are arranged on opposite sides of a longitudinal engine plane. The first cooling chamber is fluidly connected to a second cooling chamber adjoining the cylinder liner in the direction of the crankcase, which is connected to the distribution channel via at least one transfer port.

[0005] AT 501 008 A2 discloses a liquid-cooled internal combustion engine with a cooling jacket around the cylinders in the crankcase, with individual cylinder heads having at least two cooling chambers arranged one above the other in the cylinder head, wherein the cooling jacket of the crankcase and the lower cooling chamber in the cylinder head are connected to each other via four transfer openings evenly distributed around the circumference of the cylinder per cylinder. A coolant inlet distribution chamber and a coolant return collection chamber are arranged along a crankcase side wall. The inlet distribution chamber is connected to the cooling jacket of the crankcase via at least one connecting channel per cylinder, each connecting channel opening radially into the cooling jacket. The return collection chamber is connected to the lower cooling chamber of the cylinder head. EP 3 379 063 A1 discloses an internal combustion engine with a cylinder head featuring a top-down cooling concept and parallel, flow-connected block cooling jackets.

[0006] Especially in large, high-performance engines, sufficient heat dissipation from thermally stressed areas is of great importance, but is not always guaranteed with solutions known from the state of the art.

[0007] It is therefore an object of the invention to enable the best possible and most uniform cooling of thermally stressed areas in an internal combustion engine of the type mentioned above, with minimal manufacturing effort.

[0008] Starting from an internal combustion engine of the type mentioned at the outset, this is achieved according to the invention by the block cooling jacket having a first block part cooling jacket facing the fire deck, into which the second flow passage opens, and a second block part cooling jacket separate from the first block part cooling jacket and arranged on a side of the first block part cooling jacket facing away from the fire deck, wherein the first block cooling jacket is flow-connected to the second block cooling jacket via at least one third flow passage in the cylinder block arranged diametrically to the second flow passage with respect to the cylinder axis, and wherein the second block part cooling jacket is connected to a main drain channel arranged in the cylinder block.

[0009] Because the third flow passage is arranged diametrically opposite to the second flow passage, the first block cooling jacket is traversed by flow between two diametrically opposed longitudinal sides of the cylinder. Particularly in an embodiment of the invention, in which the first block cooling jacket predominantly—i.e., by a wrap angle of more than 180°—or preferably completely, surrounds the cylinder liner, comprehensive flow around the cylinder liner and effective heat dissipation from an upper region of the cylinder facing the cylinder head is achieved.

[0010] Preferably, the third flow passage and the second flow passage are arranged on opposite sides of the engine's longitudinal plane. This allows the flow around the cylinder liner transversely to the engine's longitudinal plane. In particular, the third flow passage can be arranged on the intake side.

[0011] One embodiment of the invention provides that the first flow passage – relative to the longitudinal plane of the engine – is located on the same side as the main inlet channel, preferably – viewed in the direction of the cylinder axis – above the main inlet channel. The coolant thus flows directly into the first cylinder head chamber of the cylinder head via the shortest possible path.

[0012] In particular, the main inlet channel – viewed in the direction of the cylinder axis – can be arranged between the main outlet channel and a cylinder head sealing plane. This allows for a structurally compact arrangement. Particularly good heat dissipation can be achieved if the main outlet channel is located adjacent to the main inlet channel on the exhaust side of the cylinder block.

[0013] Preferably, the first flow passage – relative to the engine's longitudinal plane – is located on the same side as the second flow passage. Thus, the coolant inflow to the first cylinder head cooling chamber and the coolant outflow from the second cylinder head cooling chamber of the cylinder head occur on the same side of the engine's longitudinal plane, namely on the exhaust side.

[0014] For optimal and uniform cooling of the cylinder liner, it is advantageous if the two block cooling chambers are arranged one above the other with respect to the cylinder axis, with the first block cooling jacket positioned between the second block cooling jacket and the cylinder head sealing plane. It is beneficial if the first block cooling jacket and / or the second block cooling jacket surround / surround the cylinder liner at least predominantly, preferably completely.

[0015] In order to ensure sufficient heat dissipation from the thermally highly stressed areas of the valve bridges, one embodiment of the invention provides that the lower second head cooling chamber has an inner ring section around the central component and an outer ring section - viewed in the direction of the cylinder axis - in the area of ​​the cylinder liner, wherein the inner ring section and the outer ring section are flow-connected to each other via at least one radial channel in the area of ​​an exhaust valve bridge and / or in the area of ​​an intake / exhaust valve bridge.

[0016] Particularly good cooling of the central component can be achieved if at least one transfer channel in the intermediate deck surrounds the central component in a ring shape.

[0017] The internal combustion engine can be self-igniting or spark-igniting, preferably with an active or passive pre-chamber - i.e. with a so-called PCSI cylinder head (PCSI=pre-chamber spark ignition).

[0018] According to one embodiment of the invention, the cylinder head is designed as a single cylinder head. However, in principle, there is nothing preventing the application of the invention with multi-cylinder heads.

[0019] The described problem is also solved according to the invention by the aforementioned method for cooling an internal combustion engine in that the coolant is supplied to a main inlet channel in the cylinder block on the exhaust side of the internal combustion engine, is guided from there via a first flow transfer and a supply channel into the first cylinder head cooling chamber, whereby the exhaust ports are cooled and flow around them, and is then guided via at least one transfer channel in the area of ​​the central component into the inner ring section of the second cylinder head cooling chamber, is guided from there via at least one radial channel in the area of ​​an exhaust valve bridge and / or exhaust / inlet valve bridge into an outer ring section, and is guided from there via the at least one second flow transfer arranged on the exhaust side into the first block cooling jacket.The coolant is guided from the exhaust side to the intake side by flowing around an upper area of ​​the cylinder liner facing the fire deck, is guided via a third flow transfer on the intake side into the second block cooling jacket, and is guided by flowing around a lower area of ​​the cylinder liner facing away from the fire deck to a main drain channel located on the exhaust side of the cylinder block.

[0020] According to one embodiment of the invention, the coolant is guided through the cylinder head cooling chamber and the block cooling jacket in at least four channels running transversely to the longitudinal direction of the engine, between its entry into the first cylinder head cooling chamber and its exit through the main drain channel. Preferably, at least two of these channels—particularly in the cylinder block—intersect the longitudinal plane of the engine. The cylinder head and cylinder block are thus each cooled optimally in two channels oriented transversely to the longitudinal axis of the engine. A channel is defined here as a substantially continuous heat transfer surface between two 180° redirections of the flow path through the cylinder head and block cooling chambers.

[0021] The invention will be explained in more detail below with reference to the non-limiting embodiment shown in the figures. These schematically show: Fig. 1 shows an internal combustion engine according to the invention in a longitudinal section along line II. Fig. 2 ; Fig. 2 the second headboard cooling chamber in a section along line II-II in Fig. 1 ; and Fig. 3 a schematic representation of the internal combustion engine according to the invention.

[0022] The Fig. 1 Figure 1 schematically shows a liquid-cooled internal combustion engine 1 according to the invention in longitudinal section perpendicular to a crankshaft axis (not shown). The internal combustion engine 1, for example a large engine, can be designed as a compression-ignition or spark-ignition engine – for example with PCSI (PCSI = pre-chamber spark ignition).

[0023] The internal combustion engine 1 has a cylinder head 2 - for example a single cylinder head - and a cylinder block 3, which are connected to each other in the area of ​​a fire deck 4 of the cylinder head 2. Fig. 3 Figure 1 shows a schematic representation of an internal combustion engine 1 designed as a single cylinder, with a cylinder head 2 and a cylinder block 3.

[0024] Reference numeral 5 designates a cylinder head sealing plane between cylinder head 2 and cylinder block 3. The intake side 6 and the exhaust side 7 of the internal combustion engine 1 are arranged on opposite sides of a longitudinal engine plane 9 spanned by the crankshaft (not shown) and the cylinder axis 8.

[0025] The cylinder head 2, for example, which is designed as a single cylinder head, has two intake valves 10 and two exhaust valves 11, with intake ports 12 being connected to the combustion chamber 14 via the intake valves 10 and exhaust ports 13 via the exhaust valves 11. The cylinder head 2 can also be designed as a multi-cylinder head.

[0026] In the Fig. 1 The cooling chambers and coolant flow paths in cylinder head 2 and cylinder block 1 are shown partially schematically. A so-called top-down cooling concept is employed. Within the scope of this disclosure, such a concept is understood to mean, in particular, that a coolant flow in cylinder head 2 is directed towards cylinder block 3 or fire deck 4. In other words, coolant is guided in one direction along the cylinder axis 8 from a region remote from fire deck 4 or cylinder block 3 to fire deck 4 or cylinder block 3, thereby achieving a high cooling effect, especially at the thermally stressed fire deck 4.

[0027] The cylinder head 2, which features a top-down cooling concept, has a head cooling chamber 15 with an upper first head cooling chamber 16 and a lower second head cooling chamber 17, which are separated from each other by an intermediate deck 18. The upper first head cooling chamber 16 is therefore located further away from the cylinder block 3 in one direction along the cylinder axis 8 than the lower second head cooling chamber 17. The upper first head cooling chamber 16 and the lower second head cooling chamber 17 are fluidically connected to each other in the area of ​​a central component 19, which in the exemplary embodiment is arranged in a receiving sleeve 20 located in the cylinder head 2, via at least one transfer channel 21 in the intermediate deck 18. The term "central" here is to be understood particularly with regard to the cylinder axis 8, so that a central component 19 is arranged as close as possible to or within the cylinder axis 8.Component 19 can be formed by a fuel injection device, particularly in the case of a diesel internal combustion engine, or by a pre-chamber ignition unit, in the case of a gasoline internal combustion engine.

[0028] As is common with cylinder heads 2 with top-down cooling concepts, the cylinder head 2 is cooled from top to bottom - i.e., from an area far from the fire deck 4 of the cylinder head 2 - to an area near the fire deck 4. The coolant is supplied to the upper first cylinder head cooling chamber 16, flows through the first cylinder head cooling chamber 16 while cooling the exhaust ports 13, and enters the lower second cylinder head cooling chamber 17 adjacent to the fire deck 4 via the transfer channel 21 located near the cylinder axis 8 in the area of ​​the central component 19, with the coolant flowing from an inner ring section 22 via a radial channel 23 in the area of ​​the exhaust valve bridge 24 located between two exhaust valves, and optionally also via radial channels 25 in the area of ​​the intake / exhaust valve bridges 26 between intake and exhaust valves 10, 11 and / or a radial channel 27 between the two intake valves 10 into the outer ring section 25. Fig. 2 Figure 1 shows the shape of the second cylinder head cooling chamber 17 in a top view along the cylinder axis (the plane of the image is parallel to the cylinder head sealing plane 5), indicating the position of the intake valves 10 and exhaust valves 11. Optimal cooling around the exhaust valve seats is achieved by the flow from the inner ring section 22 via the radial channels 23, 25, 27 to the outer ring section 28 of the second cylinder head cooling chamber 17.

[0029] The cylinder block 3 has an upper first block cooling jacket 29 and a lower second block cooling jacket 30 surrounding the cylinder liner 31, which can be either dry or wet. The first block cooling jacket 29 is located between the second block cooling jacket 30 and the cylinder head sealing plane 5. The first block cooling jacket 29 and the second block cooling jacket 30 are separated from each other in their arrangement on the cylinder liner 31. In other words, a first block cooling jacket 29 and a second block cooling jacket 30 are provided on the cylinder liner 31, separated from each other along the cylinder liner 31, with the second block cooling jacket 30 being located on a side of the first block cooling jacket 29 facing away from the fire deck 4.Furthermore, a main inlet channel 32 and a main outlet channel 33 for coolant are integrated into the cylinder block 3 on the outlet side 7, wherein the main inlet channel 32 is arranged between the main outlet channel 33 and the cylinder head sealing plane 5.

[0030] In the Fig. 1 In the illustrated embodiment, the cylinder liner 31 is designed to be wet, with two separate annular spaces 29a, 30a formed between the cylinder liner 31 and the cylinder block 3, which constitute the first and second block cooling chambers 29, 30. The cylinder liner 31 has a flange 31a with sealing rings 40, which bear tightly against a mating surface of the cylinder block 3 and thus form a liquid-tight separation zone 42 between the first block cooling jacket 29 and the second block cooling jacket 30.

[0031] The main inlet channel 32 is connected via a first flow transfer 34 in the fire deck 4 of the cylinder head 2 and a supply channel 35 to the first cylinder head cooling chamber 16. The second cylinder head cooling chamber 17 is connected via a second flow transfer 36 in the fire deck 4 to the first block cooling jacket 29. The second block cooling jacket 30 is connected to the main outlet channel 33. The first block cooling jacket 29 is connected to the second block cooling jacket 30 via a third flow transfer 36. The third flow transfer 37 runs offset from the cylinder liner 31 in the cylinder block 3.

[0032] The first flow transfer 34, the second flow transfer 36, the main inlet channel 32 and the main outlet channel 33 are arranged on the outlet side 7, the third flow transfer 37 is arranged essentially diametrically opposite to the second flow transfer 36 - with respect to the cylinder axis 8.

[0033] The liquid coolant is supplied to the internal combustion engine 1 via the main inlet channel 31 in the cylinder block 3 on the exhaust side 7 of the internal combustion engine 1. From this main inlet channel 32, the coolant is guided via the first flow passage 34 and the supply channel 35, which is designed, for example, parallel to the cylinder axis 8, into the upper first cylinder head cooling chamber 16, whereby the exhaust ports 13 are cooled and flow around them.The coolant is then guided via at least the, for example, annular transfer channel 21 in the area of ​​the central component 19 into the inner ring section 22 of the lower second cylinder head cooling chamber 17 and from there via at least one radial channel 23 in the area of ​​the exhaust valve bridge 24 between two exhaust valves 11 and / or in the area of ​​at least one exhaust / intake valve bridge 26 between an exhaust valve 11 and an intake valve 10 into the outer ring section 28 in the area of ​​the cylinder rim 38 of the cylinder 39. From the outer ring section 28, the coolant is guided via the second flow transfer 36 located on the exhaust side 7 into the upper first block cooling jacket 29 of the cylinder block 3, which surrounds the cylinder liner 31 like a mantle, and is guided from the exhaust side 7 to the intake side 6 while flowing around the upper area of ​​the cylinder liner 31 adjacent to the cylinder head sealing plane 5.The coolant is guided through the third flow passage 37, located on the inlet side 6 between the first block cooling jacket 29 and the second block cooling jacket 30, into the lower second block cooling jacket 30, which surrounds the cylinder liner 31 like a jacket. From there, it flows around the lower region of the cylinder liner 31 to the main drain channel 33 located on the outlet side 7 of the cylinder block 3. The coolant is then discharged from the internal combustion engine 1 and, for example, supplied to a coolant cooler (not shown). The first block cooling jacket 29 and the second block cooling jacket 30 are flowed through sequentially (in series). The third flow passage 37 can, for example, be formed by a transfer port located in the cylinder block 3.

[0034] The coolant is thus guided between its entry into the upper first cylinder head cooling chamber 16 and its exit through the main drain channel 33 in at least several – for example, four – channels S1, S2, S3, S4 running transversely to the longitudinal engine plane 9 through the cylinder head cooling chamber 16 and the block cooling jacket 41, with at least the two channels S3, S4 intersecting the longitudinal engine plane 9 in the cylinder block 3. Here, a channel denotes a substantially continuous heat transfer surface between two 180° redirections of the flow path through the cylinder head 15 and block cooling chambers 41.

[0035] In this way, efficient cooling of thermally critical areas is achieved in both the cylinder head 2 and the cylinder block 3.

Claims

1. Liquid-cooled internal combustion engine (1), in particular a large engine, having an inlet side (6) and an outlet side (7), which are arranged on different sides of an engine longitudinal plane (9) defined by a cylinder axis (8) and a crankshaft axis, having a cylinder head (2) comprising a top-down cooling concept with a fire deck (4) adjacent to a cylinder block (3) and a head cooling chamber (15) with a first head section cooling chamber (16) spaced from the fire deck (4) and a second head section cooling chamber (17) adjoining the fire deck (4) of the cylinder head (2), which is separated from the first head section cooling chamber (16) by an intermediate deck (18), wherein the first head section cooling chamber (16) and the second head section cooling chamber (17) are connected to each other at least in the region of a central component (19) via at least one transfer channel (21) in the intermediate deck (18), having a main inlet channel (32) arranged in the cylinder block (3), which is connected via the first flow transfer (34) in the fire deck (4) of the cylinder head (2) and a supply channel (35) to the first head section cooling chamber (16), having at least one block cooling jacket (41) which is connected to the second head section cooling chamber (17) via at least one second flow transfer (36) in the fire deck (4) of the cylinder head (2) and which at least partially surrounds a cylinder liner (31), characterised in that the block cooling jacket (41) has a first block section cooling jacket (29) facing the fire deck (4), into which the second flow transfer (36) opens, and a second block section cooling jacket (30) which is separate from the first block section cooling jacket (29) and is arranged on a side of the first block section cooling jacket (29) facing away from the fire deck (4), wherein the first block section cooling jacket (29) is connected to the second section block cooling jacket (30) via at least one third flow transfer (37) arranged diametrically to the second flow transfer (36) with respect to the cylinder axis (8), and wherein the second block section cooling jacket (30) is connected to a main outlet channel (33) arranged in the cylinder block (2).

2. Internal combustion engine (1) according to claim 1, characterised in that the third flow transfer (37) and the second flow transfer (36) are arranged on different sides of the engine longitudinal plane (9).

3. Internal combustion engine (1) according to claim 1 or 2, characterised in that the first flow transfer (34) is arranged on the same side as the main inlet channel (32) relative to the engine longitudinal plane (9), preferably on the outlet side (7).

4. Internal combustion engine (1) according to one of claims 1 to 3, characterised in that the first flow transfer (34) is arranged on the same side as the second flow transfer (36) relative to the engine longitudinal plane (9), preferably on the outlet side (7).

5. Internal combustion engine (1) according to one of claims 1 to 4, characterised in that the main inlet channel (32) is arranged between the main outlet channel (33) and a cylinder head sealing plane (5).

6. Internal combustion engine (1) according to one of claims 1 to 5, characterised in that the two block section cooling jackets (29, 30) are arranged one above the other relative to the cylinder axis (8), wherein the first block section cooling jacket (29) is arranged between the second block section cooling jacket (30) and a cylinder head sealing plane (5).

7. Internal combustion engine (1) according to one of claims 1 to 6, characterised in that the third flow transfer (37) is arranged on the inlet side (6).

8. Internal combustion engine (1) according to one of claims 1 to 7, characterised in that the main outlet channel (33) is arranged adjacent to the main inlet channel (32) on the outlet side (7) in the cylinder block (3).

9. Internal combustion engine (1) according to one of claims 1 to 8, characterised in that the first flow transfer (34) and / or the second flow transfer (36) is / are arranged on the outlet side (7).

10. Internal combustion engine (1) according to one of claims 1 to 9, characterised in that the second head section cooling chamber (17) has an inner ring section (22) around the central component (19) and an outer ring section (28) - as viewed in the direction of the cylinder axis (8) - in the region of the cylinder liner (31), wherein the inner ring section (22) and the outer ring section (28) are flow-connected to each other via at least one radial channel (23, 25) in the region of at least one outlet valve bridge (24) and / or in the region of at least one inlet / outlet valve bridge (26).

11. Internal combustion engine (1) according to one of claims 1 to 10, characterised in that at least one transfer channel (21) is formed in an annular manner in the intermediate deck (18), wherein the transfer channel (21) in the intermediate deck (18) preferably surrounds the central component (19) in an annular manner.

12. Internal combustion engine (1) according to one of claims 1 to 11, characterised in that the cylinder head (2) is designed as a single cylinder head.

13. Internal combustion engine (1) according to one of claims 1 to 12, characterised in that the internal combustion engine (1) is designed to be self-igniting or externally ignited, in particular with an active or passive prechamber.

14. Method for cooling an internal combustion engine (1) according to one of claims 1 to 13, characterised in that the coolant is fed to a main inlet channel (32) in the cylinder block (3) on the outlet side (7) of the internal combustion engine (1), from there via a first flow transfer (34) and a supply channel (35) into the first head section cooling chamber (16), wherein the coolant flows around the outlet channels (13) and cools them in the process, and is then guided via at least one transfer channel (21) in the region of a central component (19) into the inner ring section (22) of the second head section cooling chamber (17), guided from there via at least one radial channel (23) in the region of an outlet valve bridge (24) and / or an inlet / outlet valve bridge (26) into an outer ring section (28), guided from there via the at least one second flow transfer (36) into the first block section cooling jacket (29), the coolant is guided from the outlet side (7) to the inlet side (6) while flowing around an upper region of the cylinder liner (31) facing the fire deck (4), is guided via a third flow transfer (37) on the inlet side (6) into the second block section cooling jacket (30) and is guided by flowing around a lower region of the cylinder liner (31) facing away from the fire deck (4) to a main outlet channel (33) arranged on the outlet side (7) of the cylinder block (3).

15. Method according to claim 14, characterised in that the coolant is guided between the inflow into the first head section cooling chamber (16) and the outflow through the main outlet channel (33) in at least four passages (S1, S2, S3, S4) running transversely to the engine longitudinal plane (9) through the head cooling chamber (15) and the block cooling jacket (41), wherein preferably at least two passages (S3, S4) - in particular in the cylinder block (3) - intersect the engine longitudinal plane (9).