CN108167085B

CN108167085B - Cylinder head

Info

Publication number: CN108167085B
Application number: CN201711276745.0A
Authority: CN
Inventors: A·泽尔克; M·克拉姆普菲尔; J·吉尔特尔; M·布雷顿勃格; C·诺马耶
Original assignee: AVL List GmbH
Current assignee: AVL List GmbH
Priority date: 2016-12-07
Filing date: 2017-12-06
Publication date: 2024-08-02
Anticipated expiration: 2037-12-06
Also published as: AT518998A4; EP3333398B1; EP3333398A1; CN108167085A; AT518998B1; KR20180065940A; KR102401326B1

Abstract

The invention relates to a cylinder head of a liquid-cooled internal combustion engine, the cylinder head (1) having a cooling chamber structure (5) which adjoins a flame-proof plate (3) and is divided by an intermediate plate (4) arranged substantially parallel to the flame-proof plate into a lower cooling chamber and an upper cooling chamber on the flame-proof plate side, the upper cooling chamber being arranged on the side of the intermediate plate facing away from the flame-proof plate in the direction of the cylinder axis, and the upper cooling chamber (5 b) and the lower cooling chamber (5 a) being connected in flow-through via at least one overflow opening extending around the cylinder axis, which overflow opening is preferably arranged in the vicinity of a receiving sleeve. The object of the present invention is to provide a cylinder head with an optimal cooling for high thermal load areas. This object is achieved by the following method: the overflow opening has at least one annular segment portion (6 a) extending annularly around the cylinder axis and a bulge portion (6 b) originating from the annular segment portion, the bulge portion facing away from the cylinder axis in a radial direction.

Description

Cylinder head

Technical Field

The invention relates to a cylinder head of a liquid-cooled internal combustion engine, wherein the cylinder head has a cooling chamber structure which adjoins a flame-proof plate and is divided by an intermediate plate arranged substantially parallel to the flame-proof plate into a lower cooling chamber and an upper cooling chamber on the flame-proof plate side, wherein the upper cooling chamber is arranged on the side of the intermediate plate facing away from the flame-proof plate in the direction of the cylinder axis, and the upper cooling chamber and the lower cooling chamber are connected in flow via at least one overflow opening extending around the cylinder axis, which overflow opening is preferably arranged on a receiving sleeve. The invention also relates to an internal combustion engine with such a cylinder head.

Background

From the applicant's AT 005 939 U1 a cylinder head is known in which coolant flows from an upper cooling chamber into a lower cooling chamber via an annular overflow opening between an intermediate plate and a receiving sleeve for the central part. From the lower cooling chamber, the coolant is discharged into the cooling chamber of the crankcase via the transfer opening. In this case, the flow moves uniformly through the valve bridge, but without any special directional effect, which may lead to a compromised cooling effect in certain applications. AT 503 A2 shows a similar solution.

In AT 510 857 B1, an inflow channel is provided between the upper and lower cooling chambers, which inflow channel has an annular or annular segment-shaped inlet opening in the central region. Adaptation to the local heat requirements of the subsequent valve bridge passages is thus sought in order to improve the heat dissipation in the region of the exhaust valve seat and the valve bridge.

The known arrangement has the disadvantage that it is only inadequately suitable for cooling the region of the cylinder head where the thermal load is great, which may prove necessary in certain applications. The flow distribution through the different radial cooling channels can be set only by the size of the overflow opening to the cylinder housing. The radial cooling channels on the inlet side are thus cooled as are the radial cooling channels on the outlet side, but this is disadvantageous for the temperature distribution over the flame retardant panel. The uneven temperature distribution that occurs on the flame retardant panel results in material stresses in the cylinder head. At the same time, the cross-sectional area of the overflow opening can be widened only to a limited extent due to the strength of the cylinder head, so that it can lead to an insufficient supply of coolant or unfavorable pressure conditions. Furthermore, since the cooling water flows in the vertical direction through the overflow opening to the flame-proof plate and then directly into the radial cooling channels, no target flow around the receiving sleeve is possible in the lower cooling chamber through the annular overflow opening.

Disclosure of Invention

The object of the present invention is to avoid these drawbacks and to ensure optimal cooling of the highly thermally stressed areas of the fire protection plate and the receiving sleeve.

This object is achieved by the cylinder head according to the beginning of the invention in that the overflow opening has at least one circular ring segment portion extending annularly around the cylinder axis and a bulge portion originating from the circular ring segment portion and facing away from the cylinder axis in the radial direction. In other words, the overflow opening thus has a first portion extending in a circular ring segment around the cylinder axis and a second portion originating from the first portion, the second portion being designed as a radially protruding portion facing away from the cylinder axis in the radial direction.

A circular ring segment in the sense of the present invention is a circular (shaped) ring segment extending over an angular range of less than 360 °.

For the purposes of this disclosure, a cylinder axis is understood to be the longitudinal central axis of the cylinder, which extends substantially orthogonal to the flame retardant plate or cylinder head sealing plane.

Due to the limited extension of the annular segment portion and the bulge portion, the flow velocity increases in the transition between the cooling chambers and the flow concentrated thereby increases. In particular, due to the bulge, the cooling of the high thermal load area on the flame retardant panel in the region of the valve bridge increases and thus the temperature decreases.

In a variant of the invention, the annular segment portion extends around the cylinder axis over a first angle between 20 ° and 180 °, preferably between 30 ° and 90 °, and more preferably between 40 ° and 50 °. The projection extends through a second angle around the cylinder axis, the second angle being between 5 ° and 45 °, preferably between 5 ° and 20 °. Conveniently, the second angle is less than the first angle.

It is particularly advantageous when the overflow opening from the receiving sleeve is arranged to extend in the direction of the outlet channel, preferably between the two exhaust valves. Thus, the entire coolant flow in the upper cooling chamber is concentrated on the outlet side and an improved cooling of the outlet channel walls and the exhaust valve guide is achieved. Further, the flow through the inlet side is slightly reduced due to the concentrated flow through the outlet side. This results in a slight increase in the temperature of the inlet valve bridge, which results in a very balanced temperature level across the fire protection plate and thus can greatly reduce material stresses.

If the width of the annular segment portion extending in the radial direction is smaller than the width of the convex portion extending in the circumferential direction, a particularly concentrated flow with a good cooling effect can be achieved. In other words, the width of the annular segment portion is defined as its extension in the radial direction, and the width of the projecting portion is defined as its extension in the circumferential (circumferential) direction around the cylinder axis.

The annular segment portion has an extension (hereinafter referred to as the length of the annular segment portion) in the circumferential direction about the cylinder axis that is larger than an extension in the radial direction (the extension in the radial direction and hereinafter referred to as the width of the annular segment portion). In contrast, the convex portion has an extension amount (hereinafter referred to as the length of the convex portion) in the radial direction around the cylinder axis that is larger than an extension amount in the circumferential direction (the extension amount in the circumferential direction is hereinafter referred to as the width of the convex portion). An arrangement which facilitates the flow state is obtained when the relief opening extends in a circumferential direction around the cylinder axis, essentially between two connecting lines extending from the cylinder axis to the valve axis of each of the two different valves, preferably between connecting lines from the cylinder axis to the exhaust valve axes of the two exhaust valves. In one variant of the invention, the projection extends perpendicularly to the flame retardant panel along a valve symmetry plane which extends between the two valve axes, preferably between the valve axes of the respective exhaust valves. Advantageously, the extension of the bulge ends in the radial direction in front of the connection plane between the two valve axes. Thus, an advantageous balance between cooling effect and strength of the cylinder head is achieved.

Advantageously, the projection extends in a direction away from the cylinder axis via a radial cooling channel extending through the exhaust valve bridge. Thus, highly thermally stressed areas of the exhaust valve bridge can be cooled particularly effectively.

For good cooling it is also advantageous if the overflow openings are connected in a flow-through manner to cooling channels via distribution rings arranged in the lower cooling chamber around the receiving sleeve, which channels are directed radially away from the distribution rings in the lower cooling chamber. Thus, the flow can flow in a targeted manner around the receiving sleeve in the lower cooling chamber.

The object of the invention is also achieved by an internal combustion engine of the initially mentioned type with a cylinder head according to one of the variants described above.

Drawings

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

FIG. 1 shows a schematic view of a cylinder head according to the invention, taken along line I-I in FIG. 2;

FIG. 2 illustrates the cylinder head of FIG. 1 in a cross-sectional view of the upper cooling chamber region along line II-II in FIG. 1; and

Fig. 3 illustrates the cylinder head of fig. 1 in a cross-sectional view of the lower cooling chamber region along line III-III in fig. 1.

Detailed Description

Fig. 1 shows a liquid-cooled cylinder head 1 with at least one cylinder (not shown) in a section of an internal combustion engine 100, which cylinder is arranged along a cylinder axis 2. The cylinder head 1 has a flame retardant panel 3 in the direction of the combustion chamber of the cylinder. The intermediate plate 4 divides the cooling chamber structure 5 into a lower cooling chamber 5a adjacent to the fireproof plate 3 and an upper cooling chamber 5b adjoining in the direction of the cylinder axis 2.

The intermediate plate 4 has at least one overflow opening 6 per cylinder for the flow connection between the upper cooling chamber 5b and the lower cooling chamber 5a, which overflow opening is formed between the intermediate plate 4 and the receiving sleeve 7. The receiving sleeve 7 is used, for example, for receiving a fuel injection device or a spark plug and is arranged substantially concentrically with the cylinder axis 2. According to fig. 2, the overflow opening 6 from the cylinder axis 2 adjoins the receiving sleeve 7 in the radial direction and according to the invention has a circular ring segment portion 6a which extends at least partially around the cylinder axis 2 or the receiving sleeve 7, and the overflow opening 6 has a further projection 6b which extends in the radial direction. In the embodiment as top-down cooling, i.e. when coolant flows from the upper cooling chamber 5b into the lower cooling chamber 5a, an advantageous distribution of coolant and cooling can be achieved, especially for highly heated pressure areas.

The ring segment portion 6a has the shape of a circular ring segment and extends in a circumferential direction over a first angle α around the cylinder axis 2 or the receiving sleeve 7. The first angle α is between 20 ° and 180 °, wherein in the exemplary embodiment shown an angle of about 65 ° is achieved. The substantially radially extending bulge 6b extends in the circumferential direction over a second angle β between 5 ° and 45 °, wherein in the exemplary embodiment shown about 16 ° is implemented.

The second angle beta is preferably smaller than the first angle alpha. In this way, the coolant can be guided in a targeted manner to the region of the valve axis subjected to high thermal loads, in particular on the outlet side (exhaust side).

In addition to the above-described angular range in the circumferential direction about the cylinder axis 2, it is also necessary to consider the extension in the radial direction from the cylinder axis 2: in all embodiment variants, the annular segment portion 6a has a greater extension in the circumferential direction (circumferential direction) than in the radial direction. In this case, the extension in the radial direction is the width of the annular segment portion 6 a. The projecting portion 6b can be designed differently according to an embodiment variant: the width of the bulge 6b, i.e. its extension in the circumferential direction around the cylinder axis 2, may be smaller, equal or larger than the extension of the bulge 6b in the radial direction (starting from the cylinder axis 2). In the exemplary embodiment according to fig. 2 and 3, the width of the protruding portion 6b is substantially equal to the length, i.e. the extension in the radial direction. If, as is implemented in the exemplary embodiment shown, the width of the ring segment portion 6a extending in the radial direction is smaller than the width of the bulge portion 6b extending in the circumferential direction around the cylinder axis 2, an advantageous coolant distribution in the flow through the overflow opening 6 can be achieved.

In order to achieve the best possible balance between the pressure loss when flowing through the overflow opening 6 and the cooling effect in highly thermally stressed areas, such as the receiving sleeve 7 and the valve bridge, the dimensions of the overflow opening 6 are chosen as follows: the relief opening 6, in particular the annular segment portion 6a, is arranged between two connecting lines a, which lead from the cylinder axis 2 to the respective valve axes 8a, 8b of the two different valves. In principle, these may be the exhaust valve axis 8a and the intake valve axis 8b, or also the respective connecting lines a extending to the exhaust valve axis 8a and the intake valve axis 8b. However, in the exemplary embodiment according to fig. 2, the connecting line a is arranged between the cylinder axis 2 and the exhaust valve axis 8a. This is advantageous because the highest thermal stresses occur on the outlet side (exhaust side) during operation. The connecting lines a connect the respective valve axes 8a, 8b to the cylinder axis 2. At the same time, the bulge 6b extends orthogonally to the flame retardant panel 3 along a valve symmetry plane Z extending between the two valve axes 8a, 8b (in the exemplary embodiment shown, between the exhaust valve axes 8 a). In this case, the valve symmetry plane Z extends perpendicularly to the flame retardant panel 3 or the cylinder head sealing plane and through the cylinder axis 2 parallel to the valve axes 8a, 8b. In the radial direction, the extension of the relief opening 6, in particular the bulge 6b, ends in front of the connecting line between the two valve axes 8a, 8b associated with the valve symmetry plane Z, which in the exemplary embodiment shown are the exhaust valve axes 8a.

The drawing shows the flow of coolant in the cylinder head 1 according to the invention by means of arrows P. Corresponding to arrow P in fig. 1, coolant enters the upper cooling chamber 5b from a pressure source (not shown), such as a coolant pump, through a coolant inlet, and then flows in the vertical direction through the overflow opening 6 into the lower cooling chamber 5a, where the coolant impinges directly on the flame retardant panel 3 and cools the flame retardant panel 3.

As shown in fig. 3, the coolant is distributed in the lower cooling chamber 5a via a distribution ring 10 to, for example, four radial cooling channels 9a, 9b, 9c, 9d and flows through openings 11a, 11b, 11c, 11d further into the crankcase. It will be appreciated that fewer radial cooling channels and fewer openings may also be provided.

Via the distribution ring 10, a target flow around the receiving sleeve 7 and thus cooling of the receiving sleeve 7 is made possible. In this case, the radial cooling channels 9a, 9b, 9c, 9d are arranged in particular in the region of the valve bridge. Thanks to the design of the overflow opening 6 with the annular segment portion 6a and the bulge portion 6b, a guiding of the coolant flow is achieved and in particular the exhaust valve bridge 90, i.e. the first radial cooling channel 9a between the outlet channels 8, is effectively cooled. As can be seen from fig. 2 in combination with fig. 3, the bulge 6b extends in a direction radially away from the cylinder axis 2 via a first radial cooling channel 9a extending through the exhaust valve bridge 90. Positioning "via" is to be understood herein as in a direction leading away from the flame retardant panel 3 along the cylinder axis 2. The first radial cooling channel 9a is part of the lower cooling chamber 5a, and the protruding portion 6b is formed in the area of the intermediate plate 4. Thus, on the one hand, a relatively large amount of water is supplied to the first cooling channel 9a, and on the other hand, the exhaust valve bridge 90 is additionally cooled in the region of the intermediate plate 4.

The guiding effect is enhanced by positioning the openings 11a, 11b, 11c, 11d through which coolant from the cylinder head 1 flows into the crankcase.

The geometry shown in the exemplary embodiment in the figures and the positioning of the outlet side of the overflow opening 6 results in the outlet side being intensively cooled in both the upper cooling chamber 5b and the lower cooling chamber 5 a. This achieves an optimal cooling of the outlet channel 8 or channels, the exhaust valve guides 7a, 7b (see fig. 2) and subsequently the flame retardant panel 3 in the region of high thermal loading of the exhaust valve bridge 90. This results in a uniform temperature level over the entire flame retardant panel 3 and thus lower material stresses in the cylinder head 1. The term "valve bridge" or "exhaust valve bridge 90" means the accumulation of material between a gas exchange valve (not shown) and an exhaust valve. The exhaust bridge 90 is highly thermally loaded.

In addition to the variants shown in the embodiments of the figures, other variants are also possible, wherein, for example, the bulge 6b is arranged in the region of the intake valve bridge or intake-exhaust valve bridge, or further annular segment portions are provided, which are each or partly connected to the bulge.

The invention thus allows an increased flow velocity in the transition between the cooling chambers 5a, 5b and, due to this concentrated flow, in particular due to the bulge 6b, an improved cooling of the high thermal load areas in the region of the valve bridge (in particular the exhaust valve bridge 90) on the flame retardant panel 3 and thus a reduced temperature. Thus, thermal stresses and consequent damage to the cylinder head are prevented.

Claims

1. A cylinder head (1) of a liquid-cooled internal combustion engine, wherein the cylinder head (1) has a cooling chamber structure (5), which cooling chamber structure (5) adjoins a flame retardant plate (3) and is divided by an intermediate plate (4) arranged essentially parallel to the flame retardant plate (3) into a lower cooling chamber (5 a) on the flame retardant plate side and an upper cooling chamber (5 b), wherein the upper cooling chamber (5 b) is arranged on the side of the intermediate plate (4) facing away from the flame retardant plate (3) in the direction of the cylinder axis (2), and the upper cooling chamber (5 b) and the lower cooling chamber (5 a) are connected in flow connection via at least one overflow opening (6) extending around the cylinder axis (2), characterized in that the overflow opening (6) has at least one ring-shaped section part (6 a) extending annularly around the cylinder axis (2) and a bulge (6 b) originating from the ring-shaped section part (6 a), which bulge (6 b) is arranged in the radial direction away from the ring-shaped section part (6 a) in the radial direction of the cylinder axis (2) and at least one corner part (a) extending in the radial direction of the ring-shaped section (6 a), the bulge (6 b) extends around the cylinder axis (2) over a second angle (β) which is smaller than the first angle (α), wherein the overflow opening (6) is positioned such that the annular segment portion (6 a) overlaps and is aligned with a distribution ring (10) and such that the bulge (6 b) bulges from a radially outer edge of the distribution ring (10).

2. The cylinder head (1) according to claim 1, characterized in that the first angle (a) is between 20 ° and 180 °.

3. The cylinder head (1) according to claim 1 or 2, characterized in that the bulge (6 b) extends around the cylinder axis (2) over a second angle (β) between 5 ° and 45 °.

4. The cylinder head (1) according to any one of claims 1 to 2, characterized in that the width of the bulge (6 b) extending in the radial direction, i.e. in a direction originating from the cylinder axis (2), is smaller than the width of the bulge (6 b) extending in the circumferential direction.

5. The cylinder head (1) according to any one of claims 1 to 2, characterized in that,

The relief opening (6) extends substantially in the circumferential direction around the cylinder axis (2) between two connecting lines (a) from the cylinder axis (2) to respective valve axes (8 a, 8 b) of two different valves.

6. The cylinder head (1) according to any one of claims 1 to 2, characterized in that the bulge (6 b) extends perpendicularly to the flame retardant panel (3) along a valve symmetry plane (Z) extending between two valve axes (8 a, 8 b).

7. The cylinder head (1) according to any one of claims 1 to 2, characterized in that the bulge (6 b) extends via a radial cooling channel (9 a, 9b, 9c, 9 d) in a direction away from the cylinder axis (2), the radial cooling channel (9 a, 9b, 9c, 9 d) extending through a valve bridge.

8. The cylinder head (1) according to any one of claims 1 to 2, characterized in that the overflow opening (6) is fluidly connected to a cooling channel (9 a, 9b, 9c, 9 d) via a distribution ring (10), the distribution ring (10) being arranged in the lower cooling chamber (5 a) around a receiving sleeve (7), the cooling channel (9 a, 9b, 9c, 9 d) being directed radially away from the distribution ring (10) in the lower cooling chamber (5 a).

9. The cylinder head (1) according to claim 1, characterized in that the overflow opening (6) is arranged in the vicinity of the receiving sleeve (7).

10. The cylinder head (1) according to claim 1, characterized in that the ring segment portion (6 a) extends over a first angle (a) around the cylinder axis (2), the first angle (a) being between 30 ° and 90 °.

11. The cylinder head (1) according to claim 1, characterized in that the ring segment portion (6 a) extends over a first angle (a) around the cylinder axis (2), the first angle (a) being between 40 ° and 50 °.

12. The cylinder head (1) according to claim 1 or 2, characterized in that the bulge (6 b) extends around the cylinder axis (2) over a second angle (β) between 5 ° and 20 °.

13. The cylinder head (1) according to any one of claims 1 to 2, characterized in that,

The overflow opening (6) extends in the circumferential direction about the cylinder axis (2) between a connecting line (A) from the cylinder axis (2) to an exhaust valve axis (8 a) of the two exhaust valves.

14. The cylinder head (1) according to any one of claims 1 to 2, characterized in that the bulge (6 b) extends perpendicularly to the flame-retardant panel (3) along a valve symmetry plane (Z) extending between the exhaust valve axes (8 a) of the exhaust valves.

15. The cylinder head (1) according to claim 7, characterized in that the radial cooling channels (9 a, 9b, 9c, 9 d) extend through an outlet valve bridge (90).

16. An internal combustion engine (100) having a cylinder head (1) according to any one of claims 1 to 15.