GB2323632A

GB2323632A - Cylinder head of a multi-cylinder i.c. engine

Info

Publication number: GB2323632A
Application number: GB9805790A
Authority: GB
Inventors: Jutz Bernhard
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1997-03-29
Filing date: 1998-03-18
Publication date: 1998-09-30
Anticipated expiration: 2018-03-18
Also published as: GB9805790D0; FR2761411B1; FR2761411A1; DE19713246C2; DE19713246A1; GB2323632B

Abstract

In the cylinder head of a multi-cylinder internal combustion engine, on the circumference of each combustion space 6 assigned to a cylinder there are, between adjacent screw pipes 9, 10, 11 for the cylinder-head screws, walls 12, 13 which are integrally formed on the said pipes and run in the transverse and longitudinal directions of the cylinder head and which extend as far as the bottom of the cylinder head. In order to transmit the screw forces predominantly to the longitudinal and transverse walls 12, 13 and to ensure that the cylinder head is pressed down, particularly over the circumference of each combustion space 6, the screw pipes 9, 10, 11 end at a distance from the bottom 1 of the cylinder head.

Description

1 Cylinder Head of a Multi-cylinder Internal Combustion Engine 2323632 The

invention relates to a cylinder head of a multi-cylinder internal combustion engine.

DE-A 35 13 126 illustrates a known cylinder head, in which there are between the bottom of the cylinder head and the top of the cylinder head supporting walls which are integrally formed on the pipes receiving the cylinder-head screws, the said pipes likewise extending as far as the bottom of the cylinder head.

The present invention seeks to improve the known cylinder head in such a way as to ensure that the screw forces are distributed and that the cylinder head is pressed onto the cylinder crankcase, in particular over the circumference of each combustion space.

According to the present invention there is provided a cylinder head of a multi-cylinder internal combustion engine, comprising a casting with a cooling-water space which is delimited by a bottom, a top and lateral outer walls and through which at least one inlet port extends from each combustion space assigned to a cylinder to one outer wall and at least one outlet port to the other outer wall, and with pipes integrally formed on the top for cylinder-head screws and with supporting walls which are integrally formed on the said pipes which extend as far as the bottom, wherein the supporting walls are formed by walls which ran in the transverse and longitudinal directions of the cylinder head on the circumference of each combustion space between adjacent screw pipes, and the wall of the screw pipes ends at a distance from the bottom in the circumferential region which faces the spaces surrounded by the longitudinal and transverse walls.

In the proposal according to the invention, because the screw pipes do not extend as far as the bottom of the cylinder head, the screw forces are transmitted predominantly to the longitudinal and transverse walls surrounding each combustion space and thus ensure that the cylinder head is pressed optimally onto the cylinder crankcase along the circumference of each combustion space.

Preferably, the longitudinal walls and, if appropriate, also the outer transverse walls are offset outwards from the longitudinal mid-axes of the screw pipes.

2 Better distribution of the screw forces over a larger region of the bottom of the cylinder head is achieved thereby.

In order to improve the introduction of force, the longitudinal and transverse walls may be supported on the end faces of the screw pipes.

The side edges of the inner transverse walls may extend obliquely inwards from the end faces of the respective screw pipes to the bottom of the cylinder head, in order to increase the contact pressure of the bottom of the cylinder head between the combustion spaces.

The length of the screw pipes may amount to about 2/3 of the distance between the bottom and the top of the cylinder head.

In order to avoid a moment being exerted on the longitudinal walls due to their being connected off-centre to the screw pipes, supports may be integrally formed externally on the end faces of the screw pipes, the said supports extending as far as the bottom of the cylinder head. Interspaces for the passage of the cooling water may be provided between these supports and the adjacent longitudinal walls.

An embodiment of the invention is described below by way of example with reference to the drawings in which:

Figure 1 shows a top view of the cylinder head, Figure 2 shows a section along the line 2-2 in Figure 1, Figure 3 shows a section along the line 33 in Figure 1, Figure 4 shows a section along the line 4-4 in Figure 1, Figure 5 shows a top view of the structure consisting of the longitudinal and transverse walls, Figure 6 shows a perspective illustration of the structure illustrated in Figure 5, looking at the inlet side obliquely from above, and Figure 6 shows a perspective illustration, as in Figure 5, but looking at the outlet side obliquely from below. The cylinder head, illustrated in Figures 1 to 4, of a four-cylinder internal combustion engine consists of a casting with a bottom 1, a top 2 and lateral outer walls 3 and 4 and outer end walls which together delimit a cooling-water space 5. The underside of the bottom 1 has, for each cylinder, a combustion space 6, into which two inlet ports 7 open and from which two outlet ports 8 emanate, the said ports 3 extending through the cooling-water space 5 to the outer wall 3 and 4 respectively. For receiving the cylinder-head screws, one of which is shown at the left-hand end of Figure 2, screw pipes are integrally formed on the top 2, of which the outermost are designated by 9, those located on the inlet side by 10 and those located on the outlet side by 11. As is evident, each combustion space 6 is surrounded by four screw pipes. Provided on the circumference of each combustion space 6, between adjacent screw pipes, are transverse walls which are integrally formed on the latter and run in the transverse direction of the cylinder head and of which the outer transverse walls are designated by 12 and the inner transverse walls located between adjacent combustion spaces by 12', and longitudinal walls 13 running in the longitudinal direction of the cylinder head are provided on the outlet side and longitudinal walls 13' on the inlet side, the said walls being integrally formed on the bottom 1 and on the top 2. The longitudinal and transverse walls surround cooling- water spaces Y.

The structure consisting of the transverse and longitudinal walls is illustrated separately in Figures 5, 6 and 7. In this case, for the sake of clarity, the inlet and outlet ports passing through the longitudinal walls 13 and integrally formed on these have been omitted and only the inlet and outlet ports assigned to the righthand combustion space have been indicated in Figures 6 and 7.

In order to ensure that the forces exerted by the cylinder-head screws are distributed optimally and, consequently, the cylinder head is pressed as uniformly as possible onto the cylinder crankcase, in particular along the circumference of each combustion space, the screw pipes 9, 10 and 11 are designed with a full circumferential wall from the top 2 only as far as approximately 2/3 of the height of the cooling-water space, that is to say of the distance between the bottom 1 and the top 2, and are continued on their outsides as far as the bottom 1 by means of integrally formed supports 9a, 10a and lla. As emerges particularly from Figures 6 and 7, the inner transverse walls 12' are integrally formed only on the screw pipes 10 and 11 and the side edges 15 of the said transverse walls extend obliquely inwards from the ends 14 of the screw pipes towards the bottom 1. In a corresponding way, the longitudinal walls 13' on the inlet side are integrally formed only on the screw Pipes 9 and 10, and at least one side edge 16 extends obliquely downwards from the end 14 of the respective screw pipe to the bottom 1. The screw forces are thereby transmitted 4 predominantly to the longitudinal and transverse walls, thus ensuring that the cylinder head is pressed optimally onto the cylinder crankcase along the circumference of each combustion space and particularly between the combustion spaces. The obliquely extending side edges provide passage orifices 17 for the cooling water.

Whilst the supports lla extend over approximately 180" of the circumference of the screw pipes 11 on the outlet side, the supports 10a are so narrow on the inlet side that interspaces 17 for the passage of cooling water are produced between the said supports and the two adjacent longitudinal walls 13 and 13'.

As is evident particularly from Figure 5, the longitudinal walls 13 and 13' and the outer transverse walls 12 are offset outwards from the longitudinal mid-axes L of the screw pipes, thereby ensuring better distribution of the screw force over a larger region of the cylinder head. In the middle, these walls 12, 13 and 13' are drawn inwards, in order, despite the outward offset, to achieve support as near as possible to the circumference of each combustion space 6. As Figure 7 particularly shows, the longitudinal and transverse walls are supported on the end faces 14 of the screw pipes, thereby optimizing the introduction of the screw force onto these walls. The supports 9a, 1 Oa and 11 a, which are integrally formed externally on the end faces 14 of the screw pipes 9, 10 and 11, prevent a moment from being exerted on the longitudinal ribs. As is evident, the shape of the transverse and longitudinal walls is based on a beam of uniform bending strength.

Claims

1. A cylinder head of a multi-cylinder internal combustion engine, comprising a casting with a cooling-water space which is delimited by a bottom, a top and lateral outer walls and through which at least one inlet port extends from each combustion space assigned to a cylinder to one outer wall and at least one outlet port to the other outer wall, and with pipes integrally formed on the top for cylinder-head screws and with supporting walls which are integrally formed on the said pipes which extend as far as the bottom, wherein the supporting walls are formed by walls which run in the transverse and longitudinal directions of the cylinder head on the circumference of each combustion space between adjacent screw pipes, and the wall of the screw pipes ends at a distance from the bottom in the circumferential region which faces the spaces surrounded by the longitudinal and transverse walls.

2. A cylinder head according to Claim 1, wherein the longitudinal walls are offset outwards from the longitudinal mid-axes of the screw pipes.

3. A cylinder head according to Claim 1 or 2, wherein the outer transverse walls are offset outwards from the longitudinal mid-axes of the screw pipes.

4. A cylinder head according to any one of Claims 1 to 3, wherein the longitudinal and transverse walls are supported on the end faces of the screw pipes.

5. A cylinder head according to any one of Claims 1 to 4, wherein the side edges of the transverse walls located between adjacent combustion spaces extend obliquely inwards from the end faces of the screw pipes located between the outer screw pipes towards the bottom.

6. A cylinder head according to any one of Claims 1 to 5, wherein the length of the screw pipes amounts to approximately 2/3 of the distance between the bottom and the top.

6

7. A cylinder head according to any one of Claims 1 to 6, wherein supports are integrally formed externally on the end faces of the screw pipes, the said supports extending as far as the bottom.

8. A cylinder head according to Claim 7, wherein, on the outlet side, the supports of the screw pipes located between the outermost screw pipes extend over approximately 180' of the circumference of the screw pipes.

9. A cylinder head according to Claim 7, wherein, on the inlet side, interspaces are provided between the supports of the screw pipes located between the outermost screw pipes and the adjacent longitudinal walls.

10. A cylinder head according to Claim 9, wherein at least some side edges of the longitudinal walls extend obliquely downwards from the end faces of the screw pipes to the bottom.

11. A cylinder head of a multi-cylinder internal combustion engine, substantially as described herein with reference to and as illustrated in the accompanying drawings.