WO2005059346A1

WO2005059346A1 - An internal combustion engine system with an at least double-layer cylinder head gasket clamped between an engine block and a cylinder head

Info

Publication number: WO2005059346A1
Application number: PCT/EP2004/013533
Authority: WO
Inventors: Stefan Merkl; Juergen Schneider; Guenther Unseld; Robert Biersch; Johann Waldvogel; Andreas Goettler
Original assignee: Reinz-Dichtungs-Gmbh
Priority date: 2003-12-17
Filing date: 2004-11-29
Publication date: 2005-06-30
Also published as: DE10359286A1

Abstract

The invention relates to an internal combustion engine system (1) with an at least two-layer cylinder head gasket (4) clamped between an engine block (2) and a cylinder head (3), which gasket comprises at least one combustion chamber opening corresponding to the cylinder bore (5) of the engine block, which opening is enclosed by a bead (7). In a surface (8) to be sealed by the cylinder head gasket there is an oblong fluid opening (9) close to the combustion chamber region. The second surface (10) to be sealed is porous or comprises cavities (11) in a region remote from the combustion chamber region. The gasket layer (14) adjacent to said porous surface has a smooth section in this region (15). The other gasket layer (12) of the cylinder head gasket is adjacent to the surface (8) with the fluid opening (9) and also comprises a smooth section in the region (13) adjacent to the fluid opening and also comprises the bead (7) enclosing the combustion chamber opening.

Description

AN INTERNAL COMBUSTION ENGINE SYSTEM WITH AN AT LEAST DOUBLE-LAYER CYLINDER HEAD GASKET CLAMPED BETWEEN AN ENGINE BLOCK AND A CYLINDER HEAD

[0001] The invention relates to an internal combustion engine system consisting of an engine block and a cylinder head which are mutually sealed by means of a cylinder head gasket clamped between the two components. The invention especially relates to an internal combustion engine system in which one of the surfaces to be sealed comprises an oblong fluid opening and the second surface to be sealed comprises at least over certain regions a surface which is porous and/or comprises cavities.

[0002] As is known, defective surfaces such as the porous ones or those with cavities as mentioned herein are especially difficult to seal. In DE 19704315 A1, the applicant has already made a suggestion as to how to improve the sealing of a porous surface or one that comprises cavities. The solution consists in applying an adapter plate directly on the defective surface which is provided at least partially with an elastic/plastic or adhesive layer towards the defective surface. In this way it is possible to considerably improve the sealing ability in comparison with seals without such an adapter plate. An additional gasket layer will always be required, which in view of the available thickness of the cylinder head gasket which has to be adjusted to the height of the sealing gap is not desirable in every case.

[0003] In the present case, there are difficulties in sealing in addition to the difficulty of sealing a porous sealing surface or one containing cavities in that the second surface to be sealed is also not continuous and planar, but comprises at least one oblong fluid opening.

[0004] It is the o b j e c t of the present invention to provide an internal combustion engine system which despite the described difficult sealing conditions can be reliably sealed with a cylinder head gasket of simple configuration.

[0005] The solution of this object is achieved with the internal combustion engine system according to claim 1. Further developments and preferred embodiments are described in the sub-claims.

[0006] The invention relates to an internal combustion engine system with a cylinder head gasket clamped between an engine block and a cylinder head. The engine block comprises at least one cylinder bore which corresponds to a combustion chamber opening in the cylinder head gasket. A bead which is formed in an inherently closed manner in the cylinder head gasket about the corresponding combustion chamber opening for sealing the cylinder bore. The cylinder head gasket comprises at least two gasket layers, of which one is arranged adjacent to a first surface to be sealed and the other gasket layer is adjacent to the second surface to be sealed. An oblong fluid opening is situated in the first surface to be sealed adjacent to the combustion chamber region. The second surface to be sealed comprises at least in a region which is remote from the combustion chamber a porous surface and/or one that comprises cavities. The first gasket layer of the cylinder head gasket which is adjacent to the surface with the fluid opening comprises a section which is smooth in the region facing the fluid opening. The second gasket layer also comprises a smooth section, namely at the location where it is situated facing the porous or cavity-containing surface region of the second surface to be sealed. "Smooth" designates here a substantially plane section of the gasket layer which does not comprise any functional elements such as beads, folds, right-angle bends or the like.

[0007] This configuration of the cylinder head gasket ensures that the two surfaces to be sealed can be sealed reliably without making the structure of the cylinder head gasket especially complex. In the simplest of variants of the invention one can make do with two gasket layers to achieve a reliable sealing. It is ensured by the partly offset configuration of the smooth sections of the two gasket layers relative to their distance from the combustion chamber that in the critical regions where a porous or cavity-containing surface is situated on one of the surfaces and on the other surface there is the oblong, predominantly straight fluid opening a continuous smooth bearing surface is provided for the respective other gasket layer. These substantially smooth plate sections form a favorable bearing surface for the sealing elements in the respective adjacent gasket layer. A bead resting on a smooth section thus produces a continuous, disturbance-free, widened linear pressing which is the precondition for effective sealing.

[0008] The system in accordance with the invention is principally suitable for a large number of different types of engines, irrespective of whether the porous or cavity-containing surface on the one hand and the oblong fluid opening on the other hand are located in the engine block or cylinder head. In one variant of the invention the fluid opening is located in the cylinder head and the porous or cavity-containing surface in the engine block. The invention is also suitable for the opposite case.

[0009] The configuration of engine block and cylinder head principally corresponds to that of the state of the art. Several cylinder bores will usually be present in the engine block, to which correspond combustion chamber openings in the cylinder head gasket and which are then also sealed as described. In addition, further openings for oil, coolant and screws will be present for example in the motor block and therefore accordingly in the cylinder head gasket. These further openings can be sealed in the manner as conventionally applied in the state of the art. Preferred sealing elements are beads.

[0010] The oblong fluid opening preferably concerns a coolant slot which is used for supplying coolant close to the combustion chamber. In one embodiment of the invention the coolant slots in the cylinder head are formed in the regions which are opposite of the web regions between adjacent cylinder bores in the engine block.

[0011] The beads which enclose the combustion chamber openings of the cylinder head gasket are preferably supported by a stopper. The stopper can be arranged in front of or behind the bead when seen from the cylinder bore. It is also possible to provide one stopper each on either side of the bead. The stopper prevents in the known manner that the bead is flattened completely in operation and will thus prematurely lose its elasticity. The stopper can be provided with any configuration known from the state of the art and, as is already known from the state of the art, can change its height and/or its width in the circumferential direction about the cylinder bore.

[0012] It is principally irrelevant in which layer of the cylinder head gasket the stopper is configured. In one variant the stopper is arranged in the same gasket layer as the bead which encloses the combustion chamber opening. This possibility is especially suitable for such cylinder head gaskets which have only a low number of gasket layers, e.g. merely two gasket layers. It is especially possible in a larger number of gasket layers in the cylinder head gasket to arrange the stopper in another gasket layer than the one in which the bead is located for sealing the cylinder bore.

[0013] In a preferred embodiment of the internal combustion engine system, the stopper is configured as a wave-like, trapezoid and/or saw-tooth-like profiling of one of the gasket layers. Such a stopper is described in WO 01/96768 A1 of the applicant.

[0014] The first gasket layer which comprises a smooth sealing section in the region adjacent to the cylinder bore or combustion chamber opening where the oblong fluid opening is also located can comprise a bead in its region remote from the combustion chamber opening. In particular, the first gasket layer comprises a bead close to the gasket edge. This bead can be completely continuous in an inherently closed manner along the entire gasket edge.

[0015] If further gasket layers are present in addition to the first and second layer of the cylinder head gasket, they can also comprise further beads. Beads are appropriately situated in the region around a combustion chamber opening and/or adjacent to the gasket edge. If several gasket layers with beads are present, the beads are appropriately configured in such a way that they extend in a substantially mirror-symmetrical way relative to the beads of the respectively adjacent gasket layers.

[0016] The shape of the beads is not defined in closer detail and can be according to what is known from the state of the art. The beads can be configured as full or half beads. Half beads can especially be located close to the outer gasket edge. The beads can be angular or shaped in a round way. The combination of different forms of beads within a cylinder head gasket is easily possible.

[0017] At least one further gasket layer can be present as an additional gasket layer which does not comprise any elastic sealing elements such as beads. Such a gasket layer can comprise at least one stopper for example for a bead in another gasket layer of the cylinder head gasket. In addition to the aforementioned profiling of the gasket layer, the stopper can also be configured as a so-called omega bead (cf. JP 63214571 A) or as a fold or consists of a hard coating layer (cf. DE 198 29 058 A1).

[0018] At least one spacer layer can be additionally used in the gasket for setting the thickness of the cylinder head gasket and for thus adjusting the gasket to the height of the sealing gap to be sealed. It is usually planar and does not contain any functional elements such as beads, folds or the like.

[0019] The materials used for the cylinder head gasket also correspond to those used in the state of the art. Preferably, the cylinder head gasket is a purely metallic gasket. This does not exclude that one or several gasket layers are provided at least in sections with a non-metallic coating. Suitable are all coatings conventionally used in the field of cylinder head gaskets and especially such which ensure an especially favorable microsealing.

[0020] The metallic gasket layers preferably consist of steel, with spring steel preferably being used for such gasket layers which comprise beads or other elastic elements. Carbon steel on the other hand is suitable for spacer layers or other gasket layers without functional elements. Gasket layers with stopper elements such as the mentioned omega beads, folds or hard coating can also consist of spring steel.

[0021 ] The engine block and the cylinder head appropriately consist of materials previously known from the state of the art. The engine block can consist for example of grey cast iron, aluminum, magnesium or combinations of these materials. The cylinder head usually consists of aluminum.

[0022] The invention is now explained by reference to the enclosed drawings. The illustrated embodiments are only examples, especially as regards the number and arrangement of the layers between the two outside layers, the width of the region enclosed by the beads on the combustion chamber and the outer edge, and the dimensioning of the beads. The drawings show schematically as follows: Fig. 1 shows a first embodiment of an internal combustion engine system in accordance with the invention with a two-layer cylinder head gasket;

Fig. 2 shows a further example of an internal combustion engine system in accordance with the invention with a three-layer cylinder head gasket;

Figs. 3 and 4 show further examples of internal combustion engine systems in accordance with the invention, each with a four-layer cylinder head gasket;

Fig. 5 shows another embodiment of an internal combustion engine system in accordance with the invention with a five-layer cylinder head gasket.

Fig. 6 shows a further internal combustion engine system in accordance with the invention with a six- layer cylinder head gasket, and

Fig. 7 shows another example of an internal combustion engine system in accordance with the invention with a three-layer cylinder head gasket.

[0023] Fig. 1 shows a simple embodiment of an internal combustion engine system 1 in accordance with the invention in a cross-sectional view. The internal combustion engine system 1 comprises an engine block 2 and a cylinder head 3 between which a cylinder head gasket 4 is clamped. The illustrated cross-sectional view shows (as also all other subsequent figures) the region between a cylinder bore 5 of the engine block 2 as shown on the left side in the illustration and the outer edge of the engine block, the cylinder head 3 and the gasket 4 which are shown in the illustration on the right side. The cylinder bore 5 corresponds to a combustion chamber opening 6 in the cylinder head gasket 4. The cylinder head 3 on the other hand extends beyond the openings 5 and 6 and covers the same. This region is outside of the region depicted and therefore not shown in the figures. The engine block 2 comprises several cylinder bores 5, e.g. four cylinder bores arranged in a row. The configuration of the internal combustion engine system 1 in the region of further cylinder bores principally corresponds to what is shown in fig. 1.

[0024] The cylinder bore 5 and, respectively, the combustion chamber opening 6 of the cylinder head gasket 4 are sealed by a bead 7 which encloses the combustion chamber opening 6 in an inherently closed manner. In order to prevent the complete flattening of the bead 7 during the operation of the gasket, a stopper 16 is provided at the edge of the combustion chamber which is formed in the same gasket layer as the bead 7. The stopper 16 consists in an undulating profiling of said gasket layer 14.

[0025] In a region remote from the combustion chamber opening 6 and opposite of the bead 7 towards the gasket edge, the gasket layer 14 comprises a smooth section 15 which does not contain any functional elements such as beads, profiling or the like. The section 15 rests in a continuous manner substantially over the entire surface on the underlying region of the engine block 2. It thus covers the shrinkage cavities 11 situated in this region in the surface 10 of the engine block 2 to be sealed and thus forms a substantially smooth and planar bearing surface for the adjacently situated gasket layer 12.

[0026] The gasket layer 12 comprises a bead 7a in the region beyond the sealing element for the cylinder bore 5 (which is the bead 7 here) towards the gasket edge (which is the so-called "hinterland" of the cylinder head gasket). Said bead 7a has the shape of an angular full bead. It could also be a round full bead or a round or angular half bead. The bead 7a leads to an excellent sealing in the hinterland region of the cylinder head gasket 4, because it can use a smooth bearing surface with the section 15 of the gasket layer 14. The favorable bearing surface leads to an even, wider and continuous pressing line which would not be ensured if the bead 7a would sit directly on the surface of the engine block 2 which is provided with cavities 11.

[0027] In the region towards the combustion chamber opening 6, the gasket layer 12 comprises a smooth section 13 which especially covers the region of the surface 8 of the cylinder head 3 in which a coolant slot 9 is located. The section 13 is used as a bearing surface for the underlying bead 7 of the gasket layer 14. The advantageous effect of the section 13 corresponds to that of the section 15 for the bead 7a. Without the covering of the coolant slot 9 it would not be possible to seal the openings 5 and 6 in this region with a bead.

[0028] The functional principle of the invention with two beaded gasket layers 12 and 14 which concerning their distance from the combustion chamber each comprise mutually offset, smooth sections 13 and 15 which cover the critical surface regions of the cylinder head and the engine block can also be found in the following embodiments. Figs. 2 to 7 show the same reference numerals for the same parts as in fig. 1.

[0029] A three-layer cylinder head gasket 4 is clamped in the internal combustion chamber system 1 of fig. 2 between cylinder head 3 and the engine block 2. The outer layers 12 and 14 substantially correspond to the gasket layers 12 and 14 of fig. 1. Merely the gasket layer 14 of fig. 2 differs from that of fig. 1 in such a way that it does not have any stopper at the combustion chamber edge, but has a straight section here. The stopper 16 which is again configured as an undulating profiling is now situated in the additional gasket layer 17 which is arranged between the gasket layers 12 and 14. The stopper 16 is used both for supporting the bead 7 in the gasket layer 10 as well as the bead 7b which is arranged in the gasket layer 17. The bead 7b is configured in a mirror-inverted way relative to the bead 7 and encloses the combustion chamber opening 6 in an inherently closed manner. In the hinterland, the gasket layer 17 comprises a further bead 7c which is configured in a mirror-inverted manner relative to the bead 7a of the gasket layer 12.

[0030] Fig. 3 shows an internal combustion engine system with a four-layer cylinder head gasket 4. The gasket layers 12, 14 and 17 correspond to the gasket layers of the same numbering in fig. 2. A fourth gasket layer 18 is arranged between the gasket layers 12 and 17 which comprises a bead 7d on the combustion chamber side and a hinterland bead 7e. The two beads extend in a mirror- inverted manner relative to the beads 7b and 7c of the gasket layer 1 .

[0031] The internal combustion engine system as shown in fig. 4 is substantially identical with that of fig. 3. It is merely differs in such a way that the middle layers 17 and 18 of the cylinder head gasket 4 are exchanged, so that now the gasket layer 17 comes to lie with the stopper 16 on the gasket layer 14 on the engine side.

[0032] Fig. 5 shows a five-layer variant of the cylinder head gasket 4. The two outer gasket layers 12 and 14 correspond to that of fig. 1. The gasket layers 17 and 18 which are adjacent to the gasket layer 12 are configured according to the gasket layers 17 and 18 of the system according to fig. 3. A further gasket layer 19 is arranged between the gasket layers 14 and 18, which further gasket layer is configured in a mirror-inverted way relative to the gasket layer 18 situated above. The gasket layer 19 comprises beads 7f and 7g which run opposite to the beads 7d and 7e of the gasket layer 18.

[0033] A six-layer variant of the cylinder head gasket 4 is shown in fig. 6. In contrast to the cylinder head gasket according to fig. 5, a spacer layer 20 is inserted here between the gasket layers 18 and 19. The spacer layer 20 is a substantially planar sheet metal without functional elements such as beads, folds or profiling. The sheet-metal spacer plate 20 is used in the known manner for setting the overall thickness of the cylinder head gasket 4 in order to adjust the overall thickness to the size of the sealing gap between engine block 2 and cylinder head 3. The sheet-metal spacer plate 20 usually consists of carbon steel, whereas the gasket layers provided with beads (here and in all other figures) are usually made of spring steel. The engine block 2 consists of grey cast iron, aluminum, magnesium or combinations of these materials. The material of the cylinder head 3 is, for example, aluminum.

[0034] In the embodiments of figs. 1 to 6 the coolant opening 9 is principally present in the cylinder head 3, whereas cavities 11 can be found in the engine block 2. The invention is not limited to this constellation however. It is also suitable for the case that the coolant opening 9 is present in the engine block, whereas cavities or other defects in the surface are present in the cylinder head 3. A respective example is shown in fig. 7. [0035] The cylinder head 3 does not have any coolant slots 9, but is provided with a closed configuration. Its surface 8 is not smooth, but comprises cavities 11. Coolant openings 9 are now present in the engine block 2. The cylinder head gasket 4 is configured in such a way according to the present conditions in the surfaces 8 of the cylinder head 3 and 10 of the engine block 2 that the smooth section 13 of the gasket layer 12 comes to lie opposite of the cavities 11 in the surface 8 of the cylinder head 3. The smooth section 15 of the gasket layer 14 on the other hand is situated above the coolant opening 9 of the engine block 2.

Claims

1. An internal combustion engine system (1) with an at least two-layer cylinder head gasket (4) clamped between an engine block (2) and a cylinder head (3), wherein the engine block (2) comprises at least one cylinder bore (5) and the cylinder head gasket (4) comprises a combustion chamber opening (6) corresponding to the cylinder bore (5), with at least one of the gasket layers of the cylinder head gasket (4) comprising a bead (7) which encloses the combustion chamber opening (6) in an inherently closed fashion, and with a first of the surfaces (8) to be sealed by the cylinder head gasket (4) having an oblong fluid opening (9) in a region adjacent to the combustion chamber opening (6), and with a second of the surfaces (10) to be sealed by the cylinder head gasket (4) having a surface which is porous and/or contains cavities (11) in a region remote from the combustion chamber opening (6), c h a r a c t e r i z e d in that a first of the gasket layers (12) is arranged adjacent to the first of the surfaces (8) to be sealed and is provided with a smooth configuration in a section (1 3) which is facing the oblong fluid opening (9), and a second of the gasket layers (14) which comprises the bead (7) enclosing the combustion chamber opening (6) is arranged adjacent to the second surface (10) to be sealed and is provided with a smooth configuration in a section (15) which is facing the porous and/or cavity-containing (11) surface.

2. An internal combustion engine system according to claim 1, characterized in that the first surface (8) to be sealed is a surface of the cylinder head (3) and the second surface (10) to be sealed is a surface of the engine block (2).

3. An internal combustion engine system according to claim 1 or 2, characterized in that the oblong fluid opening (9) is a coolant slot.

4. An internal combustion engine system according to claim 3, characterized in that the coolant slot in the cylinder head (3) is arranged facing a region between adjacent cylinder bores (5).

5. An internal combustion engine system according to one of the claims 1 to 4, characterized in that the bead (7) enclosing the combustion chamber opening (6) is supported by a stopper (16).

6. An internal combustion engine system according to claim 5, characterized in that the stopper (16) is arranged in the same gasket layer as the bead (7).

7. An internal combustion engine system according to one of the claims 1 to 6, characterized in that at least one further gasket layer (17, 18, 19, 20) is arranged between first and second gasket layer (12, 14).

8. An internal combustion engine system according to claim 7, characterized in that the stopper (16) is arranged in a further gasket layer (17).

9. An internal combustion engine system according to one of the claims 5 to 8, characterized in that the stopper (16) consists of an undulating and/or saw-tooth-like profiling of the gasket layer.

10. An internal combustion engine system according to one of the claims 1 to 9, characterized in that the first gasket layer (12) comprises a bead (7a) in a region remote from the combustion chamber opening (6) and especially close to the gasket edge.

11. An internal combustion engine system according to one of the claims 9 or 10, characterized in that at least one of the further gasket layers (17, 18, 19) comprises at least one bead (7a to 7g), and especially one bead (7b, 7c, 7f) around the at least one combustion chamber opening (6) and a further bead (7a, 7e, 7g) close to the gasket edge.

12. An internal combustion engine system according to claim 11 , characterized in that the beads (7a to 7g) of the further gasket layers (17, 18, 19) are arranged in a substantially mirror-inverted way symmetrically to the beads of the respective adjacent gasket layers.

13. An internal combustion engine system according to one of the claims 7 to 12, characterized in that a substantially planar spacer layer (20) is present as a further gasket layer.