CA2670191A1

CA2670191A1 - Cylinder head gasket

Info

Publication number: CA2670191A1
Application number: CA002670191A
Authority: CA
Inventors: Thomas Schumacher; Klaus Bendl
Original assignee: ElringKlinger AG
Current assignee: ElringKlinger AG
Priority date: 2008-06-28
Filing date: 2009-06-25
Publication date: 2009-12-28
Anticipated expiration: 2029-06-25
Also published as: EP2138745B1; ATE508303T1; EP2138745A1; DE502009000616D1; CA2670191C; DE102008030787A1

Abstract

Cylinder head gasket with a gasket plate having a plurality of combustion chamber openings and comprising a single sheet metal layer extending at least substantially over the entire gasket plate, a respective opening edge area, enclosing the respective combustion chamber opening, of the sheet metal layer being folded over in order to form a combustion chamber sealing element for the respective combustion chamber opening, so that each combustion chamber sealing element has a foldover flange facing a foldover base area of the sheet metal layer. To enable such a cylinder head gasket to be manufactured without difficulty and adapted to different engine constructions, the sheet metal layer is formed by a metal sheet without spring steel properties and, in particular, a shim sheet of spring steel with a bead is inserted between foldover base area and foldover flange or the foldover base area is provided with a bead, in order to obtain combustion chamber sealing elements of changeable thickness.

Description

CYLINDER HEAD GASKET

The present disclosure relates to the subject matter disclosed in German application number 10 2008 030 787.4 of June 28, 2008, which is incorporated herein by reference in its entirety and for all purposes.

BACKGROUND OF THE INVENTION

The invention relates to a cylinder head gasket with a gasket plate having a plurality of combustion chamber openings and comprising a single sheet metal layer extending at least substantially over the entire gasket plate, a respective opening edge area, enclosing the respective combustion chamber opening, of the sheet metal layer being folded over and back onto the sheet metal layer in order to form a combustion chamber sealing element for the respective combustion chamber opening, so that each combustion chamber sealing element has a foldover flange facing a foldover base area of the sheet metal layer, edge areas of the sheet metal layer being folded over and back onto the sheet metal layer in order to form cylinder head supporting elements at a spacing from an area of the gasket plate containing the combustion chamber openings, and at least one elastomeric sealing bead for sealing around at least one fluid opening of the gasket plate being attached to the sheet metal layer.
In particular, the invention relates to a cylinder head gasket in which a shim element which encloses the combustion chamber opening is arranged between the foldover flange and the foldover base area of a combustion chamber sealing element.

Such cylinder head gaskets are disclosed in EP-0 557 918-A of ELRING
DICHTUNGSWERKE GMBH, and also in EP-0 713 988-A.

The designer of a cylinder head gasket who has been given the task of designing the cylinder head gasket for a specific engine has to deal with a number of problems:

In modern engines which are of weight-saving construction, the engine block, and, above all, the cylinder head, are, in areas thereof, not particularly resistant to deformation. Since the compressive forces with which the cylinder head gasket is clamped between the engine block and the cylinder head are applied at points, namely by the cylinder head bolts, these compressive forces are highest in the areas of the cylinder head bolts and can drop significantly in the areas between the cylinder head bolts (referred to hereinbelow as intermediate bolt areas). This applies, above all, to intermediate bolt areas in which or in the vicinity of which the engine block and/or the cylinder head is or are not particularly resistant to deformation owing to cavities such as combustion chambers and cavities for coolant or engine oil. Above all, in the areas of the compression chamber sealing elements for sealing off against the highest pressures, namely the gas pressure of the combustion gases, an excessive drop in the compressive forces acting on the cylinder head gasket can cause the engine to become untight.

A further problem has to be taken into account in so-called liner engines, in which the area of the combustion chambers lying in the engine block is formed by cylinder liners inserted into the engine block. The following constructions are known from the prior art for fixing a cylinder liner in its axial direction in an engine block: In a first type of cylinder liner, the latter has, at its one axial end area facing the cylinder head, adjacent to its axial end face, a ring collar with which the liner is placed on a ring-shaped shoulder of the engine block - in the area of this ring-shaped shoulder, the diameter of the engine block cavity accommodating the liner widens abruptly, i.e., this cavity has a larger diameter in its end area facing the cylinder head than beyond this shoulder.

In technical terminology, such liners are called top stop liners.

Two further known types of cylinder liner are referred to as mid stop liner and bottom stop liner. In the first case, the liner is supported in a central area of its axial length on the engine block, in the second case in its bottom, axial end area facing away from the cylinder head.

When in the course of assembly of a liner engine, the cylinder head is mounted and the cylinder head bolts are tightened, the liners are biased in axial direction owing to the high compressive forces acting in the area of the combustion chamber sealing elements on the cylinder head gasket, which are introduced into the liners. Since the liners cannot be regarded as absolutely rigid components, the biasing forces in mid stop and bottom stop liners act on relatively long axial sections of the liners, and so these can spring back over their entire circumference or only in circumferential areas when, during operation of the engine, upon ignition of a cylinder, in the area thereof, the cylinder head moves away from the engine block to some extent or in the intermediate bolt areas, circumferential areas of the liners are pressed less strongly in axial direction than in the areas adjacent to the cylinder head bolts.
Therefore, mid stop liners and bottom stop liners can make a certain contribution towards evening out the compressive forces acting on the cylinder head gasket around the combustion chamber openings, not only when the engine is out of operation, but also when the engine is in operation.

In the past, the complex problems surrounding cylinder head gaskets were usually solved by cylinder head gaskets whose gasket plate is formed by several sheet metal layers arranged one on the other, at least one of which consists of sheet spring steel and has sealing beads which are spring-elastically deformable in their height around combustion chamber openings.

For cost reasons, an attempt was made to replace these multilayer cylinder head gaskets by single layer gaskets of the kind defined at the outset, as also described in EP-0 557 918-A and EP-0 713 988-A.

However, the inventors of the present invention have ascertained that these known cylinder head gaskets are not without complications with respect to their manufacture, and depending on the construction of the engine to be sealed off, they are unable to reliably guarantee the necessary sealing-off, above all, around the combustion chambers, in particular, when the engine is in operation.

The object underlying the invention was to create cylinder head gaskets of the kind defined at the outset, which are uncomplicated to manufacture and, are basically designed so as to also be readiiy adaptable to different engine constructions, in particular, to so-called liner engines of the various types described hereinabove. In particular, this object is to be accomplished for larger engines, as are used in commercial vehicles.

SUMMARY OF THE INVENTION

For cylinder head gaskets of the kind defined at the outset with a shim element, enclosing the respective combustion chamber opening, between foldover flange and foldover base area of the respective combustion chamber sealing element, it is proposed, in accordance with the invention, that the shim element be configured as a shim sheet of spring steel having a bead which is resiliently elastic in its height and encloses the respective combustion chamber opening, and the sheet metal layer substantially forming the gasket plate be made from a metal sheet without spring steel properties. The following advantages are thereby gained:

If the sheet metal layer substantially forming the gasket plate does not consist of sheet spring steel, but of a more ductile and, consequently, more easily shapeable sheet steel, the foldovers around the combustion chamber openings and the foldovers serving to form supporting elements are much easier to manufacture than when a sheet of spring steel is used, which has to be heated in the area of the bending radius of the foldover to be produced, in order to be able to fold over the sheet metal. In addition, if a sheet of spring steel is used, a relatively broad foldover flange of a combustion chamber sealing element can only be produced without crack formation at the free edge of the foldover flange if the sheet metal is also previously heated in that area which later forms the free edge of the foldover flange, in order that it will lose its spring steel properties. In addition, sheets of spring steel are considerably more expensive than sheets of steel without spring-elastic properties. For engines without cylinder liners or with liners cast into the engine block (often also called crankcase) or with top stop liners, in which it is not possible to exploit the axial elasticity of a biased liner in the mounted state of the cylinder head gasket, in this solution in accordance with the invention, the height elasticity of the bead of the shim sheet of spring steel is used to even out the pressing of the combustion chamber sealing element around the combustion chamber opening and to also ensure the sealing effect of the combustion chamber sealing element during operation,of the engine when during the highest gas pressure prevailing in a combustion chamber (the so-called ignition pressure) the area of the sealing surface of the cylinder head lying above the combustion chamber sealing element is at a greater distance from the area of the sealing surface of the engine block lying under the combustion chamber sealing element than in areas in the vicinity of cylinder head bolts.

Particularly advantageous embodiments of such a cylinder head gasket in accordance with the invention are characterized by one or both of the following features: The height of the bead of the shim sheet of spring steel is from approximately 50 % to approximately 100 % of the thickness of the material of the shim sheet, and the thickness of the material of the shim sheet lies in the order of magnitude of from one tenth to two tenths of the thickness of the material of the sheet metal layer substantially forming the gasket plate. A
bead with a height in the area indicated above can, on the one hand, be produced without any difficulty in a sheet of spring steel, and ensures, on the other hand, a height elasticity of the combustion chamber sealing element, which is sufficient for fulfilling its sealing function, and with a shim sheet with a relatively small material thickness, too large a thickness of the combustion chamber sealing element (in the pressed state) is avoided, which would otherwise lead to problems in other areas of the cylinder head gasket serving sealing purposes or to an inadequate supporting of the cylinder head by the cylinder head supporting elements in the so-called hinterland of the gasket plate - hinterland areas of the gasket plate are to be understood as areas which are at a considerable distance from a combustion chamber sealing element or from the combustion chamber sealing elements, and, in particular, are peripheral areas of the gasket plate.

A second type of cylinder head gasket in accordance with the invention differs from the above-described type of cylinder head gasket in accordance with the invention in that the shim element is a shim sheet which has a bead, but may also be beadiess, and like the sheet metal layer substantially forming the gasket plate consists of a metal sheet without any spring steel properties.
Such a type of gasket is suitable for engines which are sufficiently resistant to deformation in the intermediate bolt areas of engine block and/or cylinder head and either have no cylinder liners or liners which do not show or are unable to show the spring-back effect described above, but whose end face facing the cylinder head gasket does not sink either during engine operation.
In this type of gasket the shim sheet serves to increase the compressive forces acting on the combustion chamber sealing element when the cylinder head gasket is mounted; however, since neither the shim sheet nor the sheet metal layer accommodating it consists of sheet spring steel, the combustion chamber sealing element has a so-called height adaptation capability, which means that when mounting the cylinder head gasket and/or while the engine is in operation, the thickness of the combustion chamber sealing element, owing to the area-wise differently sized compressive forces acting on the combustion chamber sealing element, is changed area-wise by a plastic deformation of the combustion chamber sealing element and thus adapts to the area-wise different width or height of the so-called sealing gap - the sealing gap is to be understood as the gap between the sealing surfaces of the cylinder head and the engine block or the cylinder liners, which is to be sealed by the cylinder head gasket.

For this type of gasket, too, it is advantageous for the thickness of the material of the shim sheet to lie in the order of magnitude of one tenth or two tenths of the thickness of the material of the sheet metal layer.

The above-described second type of cylinder head gasket in accordance with the invention may also be modified in accordance with the invention by the combustion chamber sealing elements not containing any shim sheet. Such a modified cylinder head gasket is suitable for liner engines in which the cylinder liners project relatively far over the sealing surface of the engine block that faces the cylinder head gasket, i.e., exhibit a large so-called liner projection, and, in particular, for engines with mid stop liners or bottom stop liners with a sufficiently large liner projection, as the liner projection then assumes the function of the shim sheet, namely that of elastically increasing the compressive forces acting on the combustion chamber sealing element.

A third type of cylinder head gasket in accordance with the invention does not have a shim sheet in the combustion chamber sealing elements either, but its sheet metal layer made from sheet metal without spring steel properties is provided in the foldover base area with a bead which encloses the respective combustion chamber opening, projects in the direction towards the foldover flange and, owing to the absence of a shim sheet, is immediately adjacent to this foldover flange. A combustion chamber sealing element of such design has an even better height adaptation capability as the bead can be flattened plastically, and, nevertheless, such a cylinder head gasket in accordance with the invention can be manufactured in an extremely cost-effective manner as it requires neither a shim sheet nor use of expensive spring steel.

As is apparent from the above, the cylinder head gaskets in accordance with the invention are particularly well suited for liner engines, and the gaskets are then advantageously so designed that when the cylinder head gasket is mounted, its combustion chamber sealing elements rest on the upper end faces, i.e., the sealing surfaces, of the cylinder liners.

It should also be noted that an engine with a mid stop liner is to be understood as an engine in which the axial spacing of the liner sealing surface of a liner from that point at which the liner is supported on the engine block corresponds to at least one third of the axial length of the liner.

Further features, advantages and details of the invention will become apparent from the appended claims and/or from the following description of preferred embodiments of the cylinder head gasket in accordance with the invention shown in the accompanying drawings and the engine constructions that are particularly well suited for these.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a plan view of part of a first embodiment of a cylinder head gasket in accordance with the invention;

Figure 2 shows a section taken along line 2-2 in Figure 1;
Figure 3 shows the detail "A" from Figure 2 on a larger scale;

Figure 4 shows a section taken along line 4-4 in Figure 1, but through an embodiment of the cylinder head gasket in accordance with the invention, which has been modified in relation to the first embodiment;

Figures 5-7 show representations of a third, fourth and fifth embodiment of the cylinder head gasket in accordance with the invention, which correspond to Figure 3; and Figures 8-10 show parts of an engine block, a cylinder liner and a cylinder head gasket in a section taken along a diameter plane of a combustion chamber; Figure 8 shows a top stop liner, Figure 9 a mid stop liner and Figure 10 a bottom stop liner; a sixth embodiment of the cylinder head gasket in accordance with the invention is shown in all three Figures.

DETAILED DESCRIPTION OF THE INVENTION

The cylinder head gasket shown in Figure 1 comprises a gasket plate 10 with combustion chamber openings 12, bolt holes 14 for the passage of cylinder head bolts, and fluid passage openings 16 of different configuration and arrangement for the passage of coolant or lubricating oil. For the sake of completeness, mention is made of the fact that the cylinder head gasket may have further openings, for example, for the passage of locating pins or screws, and also further fluid passage openings, for example, a passage opening for coolant between adjacent combustion chamber openings. It is also pointed out that cylinder head gaskets in accordance with the invention are provided, in particular, for larger commercial vehicle engines, as is the case with the cylinder head gasket shown in Figure 1, which has eight bolt holes 14 around the left-hand combustion chamber opening 12 in accordance with Figure 1- in smaller engines, in particular, for passenger cars, a cylinder head gasket usually has only four bolt holes around a combustion chamber opening.

As will be apparent from the following, the gasket plate 10 of the cylinder head gasket in accordance with the invention has only a single sheet metal layer 20 extending over the entire gasket plate. In the embodiment shown in Figure 1, the sheet metal layer 20 has been folded over and back onto itself around each combustion chamber opening 12 for formation of a combustion chamber sealing element 22, whereby a so-called foldover is formed, whose cross section corresponds approximately to a(ying U - in this connection reference is made to the following explanations.

In the embodiment of the cylinder head gasket in accordance with the invention shown in Figure 1, the gasket plate 10 is provided at its periphery with a further foldover extending around the circumference of the gasket plate, in order to thereby form a cylinder head supporting element 24.
Depending on the engine construction, several short supporting elements may, however, be sufficient, which, in particular, are arranged at the longitudinal ends, i.e., the narrow sides, but possibly also at one of the two longitudinal sides or at both longitudinal sides of the gasket plate 10. Alternatively or additionally, a cylinder head gasket in accordance with the invention may, however, also be provided with cylinder head supporting elements which lie in the interior of the gasket plate 10, i.e., within its circumferential edge.
For example, such supporting elements may be provided at some or all bolt holes 14 by an edge area of the gasket plate 10 that encloses a bolt hole or segments of such an edge area being folded over and back onto the sheet metal layer forming the gasket plate 10. Alternatively or additionally, such supporting elements may be provided at any location on the gasket plate 10 by a, for example, U-shaped, punched cut - in a plan view of the cylinder head gasket - being made in the sheet metal layer and a thus obtained metal tongue being folded over onto the sheet metal layer.

Around fluid passage openings 16 or groups of such passage openings, a cylinder head gasket of the kind shown in Figure 1 has sealing elements formed by elastomeric sealing beads 26 which have been applied to one or both sides of the sheet metal layer forming the gasket plate 10 and then solidified (for example, vulcanized).

The section (taken along line 2-2 in Figure 1) shown in Figure 2 through the cylinder head gasket in accordance with Figure 1 shows a sheet metal layer 100 which substantially forms the gasket plate 10 and extends over the entire gasket plate (which the exception of its openings). Figure 2 shows that sealing around the fluid passage opening 16 is effected by elastomeric sealing beads 26 which have been applied to both sides of the sheet metal layer 100 and solidified there. Figure 2 also shows details of the combustion chamber sealing element 22 and the cylinder head supporting element 24.

In order to form the combustion chamber sealing element 22, an, in particular, circular ring-shaped area of the sheet metal layer 100 was folded over through 1800 and back onto the sheet metal layer around the combustion chamber opening 12 so as to produce a so-called foldover 30 which has a foldover flange 30b above a foldover base area 30a. In order that the combustion chamber sealing element 22 will project equally far over the two sides of the adjacent flat area of the sheet metal layer 100, the sheet metal layer 100 was provided with an offset 32 between this flat area and the combustion chamber sealing element 22.

In the preferred embodiment of a combustion chamber sealing element in accordance with the invention, an, in particular, also circular ring-shaped shim sheet 34, which is more clearly apparent from Figure 3, is inserted between the foldover base area 30a and the foldover flange 30b. In accordance with the invention, this shim sheet 34 consists of sheet spring steel, whereas a sheet steel without spring steel properties was used for the manufacture of the sheet metal layer 100. The bead 36, therefore, forms a spring element which, when the combustion chamber sealing element 22 is strongly pressed in the vertical direction in accordance with Figure 3, can be compressed somewhat, but, when the combustion chamber sealing element is pressed slightly, springs up again and can then press the foldover flange 30b upwards in accordance with Figure 3 to some extent - the bead 36 thus imparts to the combustion chamber sealing element 22 certain spring-elastic properties in the vertical direction in accordance with Figure 3. In addition, the thickness of the combustion chamber sealing element 22 in the strongly pressed state is increased somewhat by the shim sheet 34 (in comparison with embodiments without a shim sheet), whereby the compressive forces acting on the combustion chamber sealing element when the cylinder head gasket is mounted are increased. As a result, this cylinder head gasket in accordance with the invention has its greatest thickness around the combustion chamber openings 12 - if the thickness of the gasket in the area of the sealing beads is disregarded.

Also for formation of the cylinder head supporting element 24, the sheet metal layer 100 was provided with a foldover 40, but the supporting element 24, in contrast to the combustion chamber sealing element 22, does not contain any inlay or shim sheet. Between the supporting element 24 and the adjacent flat area of the sheet metal layer 100, the latter was, however, also provided with an offset 42.

In this embodiment of the cylinder head gasket in accordance with the invention, its thickness in the area of the combustion chamber sealing elements 22 is greater than in the area of the supporting element 24 (or other similar cylinder head supporting elements), but less than in the areas of the elastomeric sealing beads 26, which can already be deformed by relatively low compressive forces and only have to be protected against excessive deformations - this task is assumed by the combustion chamber sealing elements 22 and the supporting element (or the supporting elements) 24.

In the modification, shown in Figure 4, of the cylinder head gasket in accordance with Figures 1 to 3, a cylinder head supporting element is missing in the area, shown in Figure 4, of the periphery of the gasket plate 10.
Instead, in this modification the sheet metal layer 100 is provided around the bolt hole 14 shown in Figure 4 with a cylinder head supporting element 46 which encloses the bolt hole 14. For formation of the supporting element 46, the sheet metal layer 100 was provided with a foldover corresponding to the foldover 40 of the supporting element 24. Several foldover segments which are spaced from one another along the circumference of the bolt hole 14 and are formed by folded-over sheet flaps of the sheet metal layer 100 could also be substituted for a circular ring-shaped foldover 46.

The modifications, shown in Figures 5 to 7, of the combustion chamber sealing element 22 in accordance with Figures 2 and 3 will be described hereinbelow only insofar as these modifications differ from the combustion chamber sealing element 22 in accordance with Figures 2 and 3.

Figure 5 shows a sheet metal layer 100', which is provided with a combustion chamber sealing element 22' and is to consist of a sheet steel without spring-elastic properties. Inserted in the foldover 30' serving to form the combustion chamber sealing element 22' is a shim sheet 34', which is overall flat and may also consist of a sheet steel without spring-elastic properties. In this embodiment, the combustion chamber sealing element 22' has no elastic properties in the direction of its height, however, when mounting the cylinder head gasket and/or when the engine is in operation, the combustion chamber sealing element 22' as well as the area of the sheet metal layer 100' forming the foldover 30' can be deformed plastically to some extent in the vertical direction in accordance with Figure 5 and thereby enable a so-called height adaptation.

The embodiment in accordance with Figure 6 differs from that in accordance with Figure 5 only in that the combustion chamber sealing element 22" of the sheet metal layer 100" does not contain any inlay within the foldover 30", i.e., it is without a shim sheet. The two embodiments in accordance with Figures 5 and 6 thus differ only in that the embodiment in accordance with Figure 6 has a combustion chamber sealing element 22" of lesser thickness.

Finally, the embodiment in accordance with Figure 7 differs from that in accordance with Figure 6 only in that a foldover base area 30a"' of the combustion chamber sealing element 22"' has a bead 36"' enclosing the combustion chamber opening 12. In accordance with the invention, the bead 36"' like the bead 36 (see Figure 3) projects in the direction towards the foldover flange 30b"' of the combustion chamber sealing element 22"', but, since the sheet metal layer 100"' is not to consist of sheet spring steel, it does not have any elastic properties in the direction of its height, but can be flattened plastically at least to some extent when the cylinder head gasket is being mounted and/or the engine is in operation.

Figures 8 to 10 show parts of an engine block 300, 300' and 300", respectively, a cylinder liner 302, 302' and 320", respectively, and a cylinder head gasket 304, 304' and 304", respectively, in accordance with the invention, which is shown only in a very simplified manner. An axis of the combustion chamber surrounded by the liner was indicated by 12a in each of Figures 8 to 10. Moreover, in all three embodiments, a combustion chamber sealing element 322, in accordance with the invention, of the cylinder head gasket rests on the respective liner, and elastomeric sealing beads 326 of the cylinder head gasket lie over the engine block.

The cylinder liner 302 of the embodiment in accordance with Figure 8 is a so-called top stop liner; it has an upper so-called liner collar 302a, which adjoins an upper end face 302b, forming a sealing surface, of the liner 302, and with which the liner is supported on a shoulder 300a of the engine block 300, which is lower in relation to a sealing surface 300b of the engine block, more specifically, to such an extent as to produce a so-called liner projection B
through which the end face 302b of the liner 302 projects over the sealing surface 300b of the engine block 300.

The embodiment in accordance with Figure 9 differs from that in accordance with Figure 8 only in that the liner 302' is supported on the engine block 300' at a considerable spacing from its upper end face 302b', more specifically, by a shoulder 302a' which rests on a shoulder 300a' of the engine block. In such a so-called mid stop liner, the spacing between the shoulder 302a' and the end face 302b' is, for example, from approximately one third to approximately half of the total axial length (not shown) of the liner 302'.

Finally, the embodiment in accordance with Figure 10 differs from that in accordance with Figure 9 only in that the shoulders 300a" and 302a" are arranged in the proximity of the bottom end of the liner 302", which is why such a liner is referred to as bottom stop liner.

When an engine has been completely assembled in accordance with the embodiments shown in Figures 9 and 10, that longitudinal area of the liner 302' and 302", respectively, which is located above the shoulder 302a' and 302a", respectively, is biased in axial direction, i.e., in the direction of the combustion chamber axis 12a, and, for example, when the engine is in operation, can expand elastically to some extent in a vertical upward direction when ignition pressure in the combustion chamber associated with the liner causes the area of the cylinder head located above the combustion chamber to be pressed upwards to some extent, and without this elastic longitudinal expansion of the liner, the combustion chamber sealing element 322 would otherwise be relieved to too great an extent. In the case of a mid stop liner or a bottom stop liner, it may, therefore, be possible to dispense with designing the combustion chamber sealing element in such a way that it has elastic properties in the direction of its thickness or height.

As mentioned above, cylinder head gaskets in accordance with the invention are provided, in particular, for engines of commercial vehicles. Particularly well suited are cylinder head gaskets in accordance with the invention, in which the foldover flange of a combustion chamber sealing element has a width (with respect to the combustion chamber opening in radial direction) which is at least 6 mm and preferably lies in the range of between 6 and 8 mm. As explained above, it is not possible or only possible with a relatively great amount of expenditure to produce such wide foldovers on sheet spring steel.
When mention is made hereinabove of the fact that the sheet metal layer substantially forming the gasket plate and possibly a shim sheet are formed by metal sheets, it is not to be excluded that these metal sheets have on one or either side, allover or only in areas thereof a coating which, in particular, consists of an elastomeric material (such thin elastomeric coatings are known in metallic cylinder head gaskets and usually serve the purpose of so-called microsealing in the event that an opposite metallic sealing surface is not completely flat but has a certain surface roughness and/or pores).

Above all, steel sheets having an elongation at break of at least 20 %, in particular, at least 30 % (elongation at break in accordance with A80, defined in European standard EN 10088-2, which is also a DIN standard) are suitable for the sheet metals without spring steel properties that are to be used in accordance with the invention.

Claims

1. Cylinder head gasket with a gasket plate having a plurality of combustion chamber openings and comprising a single sheet metal layer extending at least substantially over the entire gasket plate, a respective opening edge area, enclosing the respective combustion chamber opening, of the sheet metal layer being folded over and back onto the sheet metal layer in order to form a combustion chamber sealing element for the respective combustion chamber opening, so that each combustion chamber sealing element has a foldover flange facing a foldover base area of the sheet metal layer, a shim element enclosing the combustion chamber opening being arranged between the foldover flange and the foldover base area, edge areas of the sheet metal layer being folded over and back onto the sheet metal layer in order to form cylinder head supporting elements at a spacing from an area of the gasket plate containing the combustion chamber openings, and at least one elastomeric sealing bead for sealing around at least one fluid opening of the gasket plate being attached to the sheet metal layer, the shim element being formed by a shim sheet of spring steel having a bead which is resiliently elastic in its height and encloses the respective combustion chamber opening, and the sheet metal layer being formed by a metal sheet without spring steel properties.

2. Cylinder head gasket in accordance with claim 1, wherein the height of the bead is from approximately 50% to approximately 100 % of the thickness of the material of the shim sheet.

3. Cylinder head gasket in accordance with claim 1, wherein the thickness of the material of the shim sheet lies in the order of magnitude of from one to two tenths of the thickness of the material of the sheet metal layer.

4. Cylinder head gasket with a gasket plate having a plurality of combustion chamber openings and comprising a single sheet metal layer extending at least substantially over the entire gasket plate, a respective opening edge area, enclosing the respective combustion chamber opening, of the sheet metal layer being folded over and back onto the sheet metal layer in order to form a combustion chamber sealing element for the respective combustion chamber opening, so that each combustion chamber sealing element has a foldover flange facing a foldover base area of the sheet metal layer, edge areas of the sheet metal layer being folded over and back onto the sheet metal layer in order to form cylinder head supporting elements at a spacing from an area of the gasket plate containing the combustion chamber openings, at least one elastomeric sealing bead for sealing around at least one fluid opening of the gasket plate being attached to the sheet metal layer, and the sheet metal layer being formed by a metal sheet without spring steel properties.

5. Cylinder head gasket in accordance with claim 4, wherein a shim element which is formed by sheet metal without spring steel properties and encloses the combustion chamber opening is arranged between the foldover flange and the foldover base area.

6. Cylinder head gasket in accordance with claim 5, wherein the thickness of the material of the shim sheet lies in the order of magnitude of from one to two tenths of the thickness of the material of the sheet metal layer.

7. Cylinder head gasket with a gasket plate having a plurality of combustion chamber openings and comprising a single sheet metal layer extending at least substantially over the entire gasket plate, a respective opening edge area, enclosing the respective combustion chamber opening, of the sheet metal layer being folded over and back onto the sheet metal layer in order to form a combustion chamber sealing element for the respective combustion chamber opening, so that each combustion chamber sealing element has a foldover flange facing a foldover base area of the sheet metal layer, edge areas of the sheet metal layer being folded over and back onto the sheet metal layer in order to form cylinder head supporting elements at a spacing from an area of the gasket plate containing the combustion chamber openings, at least one elastomeric sealing bead for sealing around at least one fluid opening of the gasket plate being attached to the sheet metal layer, the foldover base area having a bead which encloses the respective combustion chamber opening, projects in the direction towards the foldover flange and is immediately adjacent thereto, and the sheet metal layer being formed by a metal sheet without spring steel properties.

8. Cylinder head gasket in accordance with claim 1, wherein the thickness of the unpressed, unmounted gasket in the area of a combustion chamber sealing element is at the most the same size as in the area of an elastomeric sealing bead and is larger than in the area of a supporting element.

9. Cylinder head gasket in accordance with claim 4, wherein the thickness of the unpressed, unmounted gasket in the area of a combustion chamber sealing element is at the most the same size as in the area of an elastomeric sealing bead and is larger than in the area of a supporting element.

10. Cylinder head gasket in accordance with claim 7, wherein the thickness of the unpressed, unmounted gasket in the area of a combustion chamber sealing element is at the most the same size as in the area of an elastomeric sealing bead and is larger than in the area of a supporting element.

11. Cylinder head gasket in accordance with claim 1 for an engine with cylinder liners, in which an end face of the cylinder liners that faces a cylinder head forms a liner sealing surface for cooperating with the cylinder head gasket, wherein the combustion chamber sealing element is so configured and arranged in the gasket plate that is rests on a liner sealing surface when the gasket is mounted.

12. Cylinder head gasket in accordance with claim 4 for an engine with cylinder liners, in which an end face of the cylinder liners that faces a cylinder head forms a liner sealing surface for cooperating with the cylinder head gasket, wherein the combustion chamber sealing element is so configured and arranged in the gasket plate that is rests on a liner sealing surface when the gasket is mounted.

13. Cylinder head gasket in accordance with claim 7 for an engine with cylinder liners, in which an end face of the cylinder liners that faces a cylinder head forms a liner sealing surface for cooperating with the cylinder head gasket, wherein the combustion chamber sealing element is so configured and arranged in the gasket plate that is rests on a liner sealing surface when the gasket is mounted.

14. Cylinder head gasket in accordance with claim 11 for an engine in which the liners have, in their axial end areas facing the cylinder head, on the outer liner circumference a collar adjoining the liner sealing surfaces in the axial direction and projecting in the radial direction, the liners being supported with the collar in the axial direction on an engine block.

15. Cylinder head gasket in accordance with claim 12 for an engine in which the liners have, in their axial end areas facing the cylinder head, on the outer liner circumference a collar adjoining the liner sealing surfaces in the axial direction and projecting in the radial direction, the liners being supported with the collar in the axial direction on an engine block.

16. Cylinder head gasket in accordance with claim 13 for an engine in which the liners have, in their axial end areas facing the cylinder head, on the outer liner circumference a collar adjoining the liner sealing surfaces in the axial direction and projecting in the radial direction, the liners being supported with the collar in the axial direction on an engine block.

17. Cylinder head gasket in accordance with claim 12 for an engine in which the liners are supported in their axial direction on an engine block at an axial spacing from the liner sealing surface, which corresponds to at least one third of the axial length of the liners.