Patent Application
20200131952
This application claims priority to German patent application DE 10 2018 218 241.8, filed Oct. 24, 2018, the entire content of which is incorporated herein by reference.
The disclosure relates to a method for mounting a valve seat ring on a cylinder head of an internal combustion engine and to a tribological system including a valve seat ring, which is mounted by carrying out this method. The disclosure further relates to an internal combustion engine including such a valve eat ring and, alternatively or additionally, including such a tribological system.
It is known to powder metallurgically produce valve seat rings for inlet and outlet valves including a functional portion and a support portion. While the functional portion is wear-resistant, among other things, the support portion contributes to the creep resistance of the valve seat ring and prevents the latter from falling out of the accommodation, which is provided for the valve seat ring on the cylinder head. In addition, the production costs are lowered with the use of a cost-efficient support material.
After the production, the so-called “double layer” valve seat rings are mounted on accommodations of cylinder heads provided for valve seat rings. The valve seat rings are thereby pressed into the accommodation, support portion first, and the functional portion facing away from the cylinder head is finished to ensure the concentricity of valve seat ring and accommodation, and a captive contact between valve body and valve seat ring. Such valve seat rings are known, for example, from DE102016109539A1.
Valve seat rings having a small ring height, in particular having a ring height of less than 4 millimeters (mm), prove to be advantageous for load change ratios of an internal combustion engine, but also to be advantageous for a cooling of the cylinders due to a smaller provided distance to a water jacket of the internal combustion engine. To produce valve seat rings having low ring height, however, new mounting and production plants need to usually be provided or the production costs need to be raised. In addition, deformations and improper mounting results more easily when arranging valve seat rings having a low ring height.
It is an object of the present disclosure to provide an improved or at least alternative method for mounting a valve seat ring on a cylinder head of an internal combustion engine. More cost-efficient valve seat rings and those, which have a lower ring height, are to in particular be mounted by such a method, wherein the above-mentioned disadvantages are eliminated or at least reduced.
This object is achieved by a method for mounting a valve seat ring on a cylinder head of an internal combustion engine as described herein.
It is a general idea of the disclosure to arrange a valve seat ring including a support portion made of a support material and including a functional portion made of a functional material on a cylinder head, and to reduce the axial ring height by removing the support material. A valve seat ring having a lower height can be mounted in this way on a cylinder head, which is located closer to the water jacket and which has better cooling properties, wherein the mounting and production plants can be used for valve seat rings having non-reduced ring height. The provision of new mounting and production plants can thus be avoided and production costs are also reduced by using the support material.
A method according to the disclosure serves the purpose of mounting a valve seat ring on a cylinder head of an internal combustion engine. According to the method, a valve seat ring is provided, which has a ring height, which is measured along an axial direction, wherein the valve seat ring includes a support portion made of a support material and a functional portion made of a functional material. This valve seat ring is arranged on the cylinder head. The support portion formed by the support material is subsequently removed at least partially, so that the ring height of the valve seat ring is reduced.
Particularly, a first axial end portion of the valve seat ring facing the cylinder head is at least partially formed by the functional portion, and a second axial end portion of the valve seat ring facing away from the cylinder head is at least partially formed by the support portion. In the case of this alternative, the support portion can be accessed particularly well for removal in response to the finishing after the arranging of the valve seat ring on the cylinder head.
According to an exemplary embodiment, a separating surface between the functional portion and the support portion runs at least in portions along a radial direction of the valve seat ring. This proves to be particularly advantageous for the arranging of the functional and support material along the direction of the force of gravity in response to a powder metallurgical production of the valve seat ring, which is mounted according to the method according to the disclosure.
According to a further exemplary embodiment, the separating surface between the functional portion and the support portion runs at least in portions along the axial direction of the valve seat ring. This also proves to be particularly advantageous for the production costs of the valve seat ring, which is mounted according to the method according to the disclosure, because support material, which is a great deal more cost-efficient, can be used in this way.
Advantageously, the functional portion abuts at least partially against an inner jacket surface of the cylinder head. In the case of this alternative, the support portion can also be accessed particularly well for an operator or the used finishing tool, respectively, after the arranging of the valve seat ring on the cylinder head for removal of the support material as part of the finishing.
Particularly advantageously, the removal of the support portion takes place in such a way that a boundary surface to the functional portion facing the support portion is at least partially exposed. This exemplary embodiment provides for a particularly cost-efficient production of the valve seat ring, which is mounted according to the disclosure, and for a particularly simple mounting of the valve seat ring.
According to an exemplary embodiment, the functional portion made of the functional material is also at least partially removed in addition to the at least partial removal of the support portion made of the support material. This provides for a particularly simple mounting of the valve seat ring.
Advantageously, the ring height measured along the axial direction is a ring height, which is formed at its maximum with respect to a radial direction of the valve seat ring.
The disclosure also relates to a tribological system, which includes a valve seat ring mounted according to the above-presented method. The above-described advantages of the method according to the disclosure and of the valve seat ring mounted according to the method according to the disclosure thus also transfer to the tribological system according to the disclosure.
The disclosure further relates to an internal combustion engine for a motor vehicle. The internal combustion engine includes a valve seat ring mounted according to the above-presented method, and, alternatively or additionally, an above-presented tribological system. The above-described advantages of the method according to the disclosure, of the valve seat ring mounted according to the method according to the disclosure, and of the tribological system according to the disclosure, thus also transfer to the internal combustion engine according to the disclosure.
Further important features and advantages of the disclosure follow from the drawings and from the corresponding figure description on the basis of the drawings.
It goes without saying that the above-mentioned features and the features, which will be described below, cannot only be used in the respective specified combination, but also in other combinations or alone, without leaving the scope of the present disclosure.
The disclosure will now be described with reference to the drawings wherein:
The method according to the disclosure will be described below in an exemplary manner on the basis of
After arranging the valve seat ring 2 on the cylinder head 3, the support portion 2b is at least partially removed in response to the finishing, so that the ring height H1 is reduced to the lower ring height H2. The functional portion 2a is also at least partially removed in response to the finishing. A dashed line shows the surface B, which limits the valve seat ring 2 after the removal of the functional and support portion 2a and 2b. A portion of the surface B, which is inclined to the axial direction A, forms the valve seat 4, against which a valve plate (not shown in
The valve seat ring 2 can be produced in a powder metallurgically manner, in particular monolithically. The functional portion 2a can be such that it is wear- and heat-resistant, and the support portion 2b can be such that it can be removed easily in response to the finishing, and, alternatively or additionally, is creep- and heat-resistant, and, alternatively or additionally, cost-efficient.
It is understood that the foregoing description is that of the exemplary embodiments of the disclosure and that various changes and modifications may be made thereto without departing from the spirit and scope of the disclosure as defined in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2018 218 241.8 | Oct 2018 | DE | national |
