CN115735053A

CN115735053A - Cylinder head for an internal combustion engine

Info

Publication number: CN115735053A
Application number: CN202180043654.0A
Authority: CN
Inventors: B·雷切; A·施拉特鲍尔
Original assignee: AVL List GmbH
Current assignee: AVL List GmbH
Priority date: 2020-06-18
Filing date: 2021-06-18
Publication date: 2023-03-03
Also published as: WO2021253065A1; AT523950A1; AT523950B1

Abstract

The invention relates to a cylinder head (1) for a liquid-cooled internal combustion engine, in particular for a large liquid-cooled internal combustion engine, with a top-down cooling concept, comprising: a lower first cooling jacket (4) adjacent to the fire protection plate (12) and an upper second cooling jacket (5) adjacent to the lower first cooling jacket (4); a plurality of scavenging valves; and a central receptacle (6) for a component which opens into the combustion chamber, in particular an injection device or a spark plug. The lower first cooling jacket (4) and the upper second cooling jacket (5) are interconnected in the region of the receptacle (6) via at least one flow connection (9), and at least one distributor duct (10) connected to the first cooling jacket (4) and/or the second cooling jacket (5) at least partially surrounds the central receptacle (6). In order to achieve optimum cooling and simplified production, the flow connection (9) between the lower first cooling jacket (4) and the upper second cooling jacket (5) has at least one connecting channel (42) which extends from the distributor line (10), is substantially parallel to the cylinder axis (1 a) and is connected to a valve bridge line (41) of the first cooling jacket (4).

Description

Cylinder head for an internal combustion engine

The invention relates to a cylinder head for an internal combustion engine, in particular a large internal combustion engine, having a lower cooling jacket adjoining a flame shield and an upper cooling jacket adjoining the lower cooling jacket, having a plurality of gas exchange valves and a central receptacle for components of each cylinder which open into a combustion chamber, in particular an injection device or a spark plug, wherein a lower first cooling jacket and the upper cooling jacket are interconnected in the region of the receptacle via at least one flow connection, and wherein at least one distributor line which is connected to the first cooling jacket and/or the second cooling jacket at least partially surrounds the central receptacle.

In a cylinder head with a top-down cooling solution, coolant is fed to the upper cooling jacket, from which it flows into the lower cooling jacket via at least one flow connection in the region of the central receptacle.

AT 005 939U1 describes a cylinder head in which the coolant flows from the upper partial cooling jacket into the lower partial cooling jacket via an annular overflow opening between the intermediate plate and the receiving sleeve for the central component. From there, the coolant is discharged through the overflow opening into the cooling jacket of the crankcase. AT 503 182A2 shows a similar solution.

In AT 510 857B1, an inflow duct is arranged between an upper partial cooling jacket and a lower partial cooling jacket, which has an annular or ring-segment-shaped inlet opening in a central region. This is intended to accommodate the local thermal requirements of the subsequent valve bridge passages to improve heat dissipation in the exhaust valve seat and valve bridge area.

Similar cylinder heads are known from WO 02005/042955A2 or WO 2015/000616 A1.

Other cylinder heads with an upper and a lower cooling jacket connected to each other via at least one connecting duct and a co-cast receptacle for components are known, for example, from CN 108 999 715A or CN 201 306 225Y.

In a cylinder head of the above-mentioned type, the space available in the area between the scavenging valve and the central part is small, which makes it difficult to manufacture the cooling jacket and the flow connection between the first cooling jacket and the second cooling jacket by means of a sand core in order to achieve optimum cooling of the critical points.

The object of the invention is to avoid these disadvantages and in particular to enable a simple production of the cylinder head which optimally cools the regions subjected to high thermal stresses.

According to the invention, this object is achieved in a cylinder head of the type mentioned above in that the flow connection between the lower first cooling jacket and the upper second cooling jacket has at least one connecting channel which extends from the distributor duct, is formed substantially parallel to the cylinder axis and is connected to the valve bridging duct of the first cooling jacket.

The distributor duct may preferably be annular and extend around the receptacle and/or cylinder axis through a first angle of 360 ° (extending at the first angle). In a further embodiment variant of the invention, the distributor duct preferably has a ring segment design and extends, for example, around the receiving portion and/or the cylinder axis at a first angle of approximately 150 ° to 210 °, preferably 180 °.

A loose core (verlorene kernel) is used to produce two cooling jackets, wherein a first cooling jacket core is used for the first cooling jacket and a second cooling jacket core is used for the second cooling jacket. The second cooling jacket core is placed on the first cooling jacket core prior to casting the cylinder head.

After the casting process, the distributor duct is located in the upper region of the lower cooling jacket, i.e. in the region of the lower cooling jacket furthest from the fire protection plate. According to an embodiment variant of the invention, the distributor duct is located approximately at half the height of the central receiving portion.

In addition to improving the cooling by a precisely defined routing (guiding) and distribution of the coolant flow from the upper cooling jacket to the lower cooling jacket, the distributor duct has other functions: on the one hand, it enables an optimal geometric and functional arrangement ("encapsulation") of the cylinder head elements and components within the available installation space. On the other hand, the support element also serves to mechanically stabilize the lower cooling jacket core as well as the upper cooling jacket core during the casting process.

The coolant flows from the engine block cooling chamber into the upper second cooling jacket of the cylinder head and via the distributor pipe into the lower first cooling jacket ("top-down cooling") and from there into the collection chamber or external collection tank. This makes it possible to cool the region subjected to high thermal loads particularly efficiently.

The central receiving portion is preferably formed by a cylinder head, which makes production particularly efficient. However, it is also conceivable to use a separate sleeve for the central receptacle, for example made of copper or stainless steel, which sleeve is formed separately from the distributor pipe.

The fact that the connecting channel is connected to the valve bridging duct (valve bridge channel) of the lower cooling jacket, which is arranged in the valve bridge region between two adjacent gas exchange valves, enables the coolant to be distributed as required to the thermally critical region of the lower first cooling jacket. The distributor duct and the at least one connecting channel parallel to the cylinder axis allow easy removal of the sand core. The connecting channel has a defined flow cross-section. As a result, the valve bridge region between two adjacent gas exchange valves, for example the region between two adjacent exhaust valves and/or between an exhaust valve and an intake valve, can be optimally cooled.

An embodiment variant of the invention provides that the flow connection between the lower first cooling jacket and the upper second cooling jacket has a plurality of connection channels which are formed substantially parallel to the cylinder axis and are each connected to a valve bridge line (valve bridge line) of the first cooling jacket, wherein a connection channel is assigned to each valve bridge line.

In particular, it is advantageous if valve bridge lines (valve bridge channels) are provided in the region of at least two, preferably four, valve bridges between adjacent gas exchange valves, each valve bridge line being assigned a connecting channel. In this way, a precisely predetermined coolant flow can be distributed to each valve bridge conduit (valve bridge channel) and thus to each valve bridge to be cooled.

In order to be able to optimally use the available installation space of the cylinder head, it is advantageous if at least one valve bridge duct, preferably each valve bridge duct, extends from the distributor duct in the region facing away from the upper second cooling jacket.

In order to further improve the cooling, according to a further embodiment variant of the invention, an overflow nozzle is provided in at least one of the connecting channels. In a subsequent machining operation, the overflow nozzle is also poured or pressed into the connecting channel after casting, for example via a demolding opening. The coolant can be metered precisely through the overflow nozzle.

In a further embodiment variant, it is provided that an annular or ring-segment-shaped cooling channel is arranged in the region of at least two nodes between the respective connecting channel and the valve bridge duct, preferably concentrically around the receptacle. The cooling channel may be annular and surround the receptacle over an angular range of 360 °. A further embodiment variant of the invention provides that the cooling channel is ring-segment-shaped and extends around the receptacle and/or the cylinder axis at a second angle of 150 ° to 210 °, preferably 180 °. This makes it possible to cool the opening of the component into the combustion chamber in a targeted manner, in particular in the region of the exhaust valve.

According to an embodiment variant of the invention, the ring segment-shaped distributor duct and the ring segment-shaped cooling channel may be arranged on different sides of a plane containing the cylinder axis, which plane is preferably a plane extending between at least one inlet valve and at least one outlet valve of the gas exchange valve.

The invention is explained in more detail below with reference to non-limiting exemplary embodiments shown in the drawings, in which:

figure 1 shows an axonometric view of a cylinder head according to the invention, in a variant of a first embodiment;

fig. 2 shows a longitudinal section of the cylinder head;

FIG. 3 shows the cylinder head in a cross-sectional view according to line III-III in FIG. 2;

FIG. 4 shows, in a sectional view similar to FIG. 3, a cylinder head according to a second embodiment variant of the invention;

FIG. 5 shows a schematic casting core diagram of a cooling jacket structure of a cylinder head in isometric view;

FIG. 6 shows a schematic casting core of the upper second cooling jacket of the cooling jacket structure of the cylinder head in isometric view;

FIG. 7 shows a schematic casting core of a lower first cooling jacket of a cooling jacket structure of a cylinder head in an isometric view;

FIG. 8 shows a schematic detail of the casting core of FIG. 7;

FIG. 9 shows a schematic casting core view of the lower first cooling jacket in isometric view from the direction of the fire shield;

fig. 10 shows a schematic casting core diagram of a lower first cooling jacket of a cooling jacket structure of a cylinder head in a further embodiment variant in an isometric view; and

fig. 11 shows a schematic illustration of the casting core from fig. 10 in an isometric view from the direction of the fire shield.

The figures all show a four-valve cylinder head 1 for one or more cylinders, or a core schematic of such a cylinder head 1, for a large or heavy engine.

The cylinder head 1 has a cooling jacket structure 2 in which a lower first cooling jacket 4 is adjacent to the flame shield 3, and an upper second cooling jacket 5 is provided above the lower first cooling jacket, adjacent to the lower first cooling jacket 4, and above the lower first cooling jacket 4 as viewed in the direction of the cylinder axis 1 a. The first cooling jacket 4 and the second cooling jacket 5 are in flow connection with one another in the region of a central receptacle 6 for a component, not shown in more detail, which leads to a combustion chamber 16. The central component may be, for example, a spark plug or an injection device. The annular receiving portion 6, which is formed concentrically with the cylinder axis 1a for example, is preferably formed integrally with the cylinder head 1, in particular by the cylinder head 1 itself.

The cylinder head 1 has a plurality of gas exchange valves, in the case of the invention two inlet valves and two exhaust valves for each cylinder, for which only the

openings

7, 8 of the respective inlet and exhaust ports into the combustion chamber 16 are shown in the drawing.

The second cooling jacket 5 and the first cooling jacket 4 are connected to one another via a flow connection 9 in the region of the central receptacle 6. An annular or ring-segment-shaped distributor line 10 is arranged in the region of the flow connection 9 between the first cooling jacket 4 and the second cooling jacket 5, which distributor line at least partially surrounds the central receptacle 6.

The distributor pipe 10 is arranged approximately at half the height of the central receiving portion 6.

The lower first cooling jacket 4 has a flame guard space 40 with a radial valve bridge duct 41 in the region of the valve bridge 11 between the

mouths

7, 8 of the two gas exchange valves and with a plurality of connecting channels 42 which are formed substantially parallel to the cylinder axis 1a and are arranged in a distributed manner around the receptacle 6. A connecting passage 42 connects the distributor duct 10 to the fire deck space 40. The flame guard space 40 is the spatial region of the first cooling jacket 4 directly adjoining the flame guard 12 of the cylinder head 1. The fire protection plate chamber 40 has a circumferential region 43 which extends in the form of a ring in the cylinder edge region of the cylinder and which surrounds the

ports

7, 8 of the gas exchange valves, as shown in fig. 3.

In the region of at least two valve bridges 11, the fire protection plate space 40 of the lower first cooling jacket 4 has a corresponding valve bridge conduit 41 between two

adjacent mouths

7, 8 of the gas exchange valve. Each connecting channel 42 is connected to a respective valve bridging duct 41 of the fire damper chamber 40. Each connecting channel 42 extends from the distributor duct 10 in a region remote from the upper second cooling jacket 5 and towards the fire protection plate 12.

As can be seen in fig. 2, the coolant flows according to the arrow P from the upper second cooling jacket 5 into the fire protection plate space 40 of the lower first cooling jacket 4 via the distributor line 10, the connecting channel 42 and the valve bridge line 41 according to a top-down cooling concept. Coolant from the connecting channel 42 thus flows radially from the inside to the outside through the valve bridge duct 41 into the annular peripheral region 43 of the fire shield space 40. From this circumferential region 43, the coolant flows to the collection chamber 44, and the corresponding region of the first cooling jacket core 400 is designated 444. The collecting chamber 44 is connected to a coolant outlet which is not shown in detail.

Fig. 4 shows an embodiment of the invention in which the transfer nozzle 13 is arranged in at least one connecting channel 42, which is cast together with the cylinder head 1 and/or pressed in after casting, for example, during the machining process. With the overflow nozzles 13, the cooling can be further improved and the distribution of the coolant optimized. The overflow nozzle 13 preferably has a tearing edge at its outlet area, which causes turbulence and turbulence of the coolant flowing into the first cooling jacket 4, which has a beneficial effect on the cooling of the high-temperature region.

Fig. 5 to 10 show core schematics of the first cooling jacket 4 and the second cooling jacket 5 of the cylinder head 1. The corresponding regions of the first cooling jacket core 400 for the fire protection plate space 40, the valve bridge duct 41, the valve bridge duct 42 and the circumferential region 43 are indicated in the core schematic by the

reference numerals

440, 441, 442 and 443. As can be seen in fig. 5, the second cooling jacket core 500 of the second cooling jacket 5 is placed on the first cooling jacket core 400 of the first cooling jacket 4. The core region 410 of the distributor duct 10 is formed as part of the first cooling jacket core 400 and is disposed adjacent to the second cooling jacket core 500. The core region 410 of the distributor duct 10 stabilizes and strengthens the first cooling jacket core 400. The two

cooling jacket cores

400, 500 are formed as loose cores.

Fig. 6 and 7 show the second cooling jacket core 500 and the first cooling jacket core 400 in a separated state and the attached support element 100. Fig. 8 shows the first cooling jacket core 400 in detail, together with the support element 100 and the distributor duct 10, in an oblique view from above and in a view from below in fig. 9. In the embodiment variant shown in fig. 5 to 9, the support element 100 with the distributor pipe 10 is formed as a ring and extends concentrically to the cylinder axis 1a over a first angle α of 360 ° around the receptacle 6.

Fig. 10 and 11 show a first cooling jacket core 400 for the first cooling jacket 4 in a further embodiment variant, wherein the core region 410 of the distributor duct 10 and the distributor duct 10 are formed as a ring segment and extend around the receptacle 6 at a first angle α of approximately 180 °. Furthermore, in the region of at least two junctions (intersections) 14 between the respective connecting channel 42 or its corresponding region 442 on the first cooling jacket core 400 and the valve bridge conduit 41 or its corresponding region 441 on the first cooling jacket core 400, a ring-segment-shaped cooling channel 45 is arranged concentrically around the receptacle 6 in the region of the mouth 8 of the outlet channel. The cooling channel 45 extends around the receiving portion 6 over a second angle β of approximately 180 °. Reference numeral 445 denotes a region of the first cooling jacket core 400 corresponding to the cooling passage 45.

As can be seen in particular in fig. 10, in the exemplary embodiment, the ring segment-shaped distributor duct 10 and the ring segment-shaped cooling channels 45 are arranged radially with respect to a plane epsilon containing the cylinder axis 1a, as viewed in the direction of the cylinder axis 1 a. The plane epsilon extends between the opening 7 of the inlet valve (inlet valve) and the opening 8 of the exhaust valve (outlet valve).

The cooling channel 45 connects the valve bridging channel 41 between the mouths 8 of the outlet channels (exhaust channels) and correspondingly between the mouths 8 of the outlet channels (exhaust channels) and the mouths 7 of the adjacent inlet channels (intake channels). The cooling channel 45 provided on the outlet side in the exemplary embodiment improves the cooling in the region of the mouth 15 of the component leading to the combustion chamber 16.

On the one hand, the described structure uses a sand core with a relatively simple shape for making the cooling chamber to allow an optimal geometrical and functional arrangement of the elements and components of the cylinder head in the available installation space, which allows easy removal of the casting sand after the casting process. On the other hand, optimum cooling of the high-temperature region of the cylinder head can be ensured.

Claims

1. A cylinder head (1) for a liquid-cooled internal combustion engine with top-down cooling concept, in particular for a liquid-cooled large internal combustion engine, comprising: a lower first cooling jacket (4) adjacent to the fire protection plate (12) and an upper second cooling jacket (5) adjacent to the lower first cooling jacket (4); a plurality of gas exchange valves; and a central receptacle (6) for a component of each cylinder which opens into the combustion chamber, in particular an injection device or a spark plug, wherein the lower first cooling jacket (4) and the upper second cooling jacket (5) are interconnected in the region of the receptacle (6) via at least one flow connection (9), and wherein at least one distributor duct (10) which is connected to the first cooling jacket (4) and/or the second cooling jacket (5) at least partially surrounds the central receptacle (6), characterized in that the flow connection (9) between the lower first cooling jacket (4) and the upper second cooling jacket (5) has at least one connection channel (42) which extends from the distributor duct (10), is formed substantially parallel to the cylinder axis (1 a) and is connected to a valve bridge duct (41) of the first cooling jacket (4).

2. The cylinder head (1) according to claim 1, characterized in that the distributor duct (10) is annular or ring-segment-shaped.

3. The cylinder head (1) according to any one of claims 1 or 2, wherein the central receiving portion (6) is integrally formed with the cylinder head (1).

4. The cylinder head (1) according to any one of claims 1 to 3, wherein the distributor duct (10) is provided at about half the height of the central receiving portion (6).

5. The cylinder head (1) according to any one of claims 1 to 4, wherein the flow connection (9) between the lower first cooling jacket (4) and the upper second cooling jacket (5) has a plurality of connecting channels (42) which are formed substantially parallel to the cylinder axis (1 a) and are each connected to a valve bridging conduit (41) of the first cooling jacket (4), wherein a connecting channel (42) is assigned to each valve bridging conduit (41).

6. The cylinder head (1) according to any one of claims 1 to 5, characterized by a valve bridge conduit (41) which is arranged in the region of at least two, preferably four, valve bridges (11) between corresponding adjacent gas exchange valves.

7. The cylinder head (1) according to any one of claims 1 to 6, characterized by at least one connecting channel, preferably each connecting channel (42), extending from the distributor duct (10) in a region remote from the upper second cooling jacket (5).

8. The cylinder head (1) according to any one of claims 1 to 6, wherein a preferably co-cast or pressed-in spill nozzle (13) is provided in the at least one connecting channel (42).

9. The cylinder head (1) according to any one of claims 1 to 8, characterized by an annular or ring-segment-shaped cooling channel (45) provided in the region of at least two junctions (14) between corresponding connecting channels (42) and valve bridge ducts (41), preferably arranged concentrically around the receptacle (6).

10. The cylinder head (1) according to any one of claims 1 to 9, wherein the ring-segment-shaped distributor duct (10) and the ring-segment-shaped cooling channel (45) are arranged on different sides of a plane (epsilon) containing the cylinder axis (1 a), wherein preferably the plane (epsilon) extends between at least one mouth (7) of an inlet valve and at least one mouth (8) of an outlet valve of the gas exchange valve.

11. The cylinder head (1) according to any one of claims 1 to 10, wherein the distributor duct (10) extends around the receiving portion (6) and/or the cylinder axis (1 a) by a first angle (a) of about 150 ° to 210 °, preferably 180 °.

12. The cylinder head (1) according to any one of claims 9 to 11, wherein the cooling channel (45) extends around the receiving portion (6) and/or the cylinder axis (1 a) by a second angle (β) of about 150 ° to 210 °, preferably 180 °.