Cylinder liner

Abstract

A cylinder liner for an internal combustion engine may include an outer circumferential surface defined by the cylinder liner composed of a gray cast iron for integrally casting onto a cast material of an engine block. A bonding component may be included for strengthening a bond of the outer circumferential surface to the cast material of the engine block. The bonding component may include at least one of a wire mesh and a wire grid that does not melt during a casting operation of the engine block. The bonding component may be arranged at least in a predefined region on the outer circumferential surface. The bonding component may be welded at least partially to the outer circumferential surface.

Claims

1. A cylinder liner for an internal combustion engine, comprising: an outer circumferential surface defined by the cylinder liner composed of a gray cast iron for integrally casting into a cast material of an engine block, a bonding component for strengthening a bond of the outer circumferential surface to the cast material of the engine block, the bonding component including at least one of a wire mesh and a wire grid that does not melt during a casting operation of the engine block, the bonding component being arranged at least in a predefined region on the outer circumferential surface, wherein the bonding component is welded in at least one region to the outer circumferential surface along a welded connection.

2. The cylinder liner as claimed in claim 1, wherein at least one of: the bonding component has a higher melting point than the cast material of the engine block, and the bonding component is made of steel.

3. The cylinder liner as claimed in claim 1, wherein the bonding component is stretched over the outer circumferential surface.

4. The cylinder liner as claimed in claim 1, wherein the welded connection includes a plurality of welding spots securing the bonding component and the outer circumferential surface together.

5. The cylinder liner as claimed in claim 4, wherein the individual welding spots of the plurality of welding spots are arranged linearly.

6. The cylinder liner as claimed in claim 5, wherein the plurality of welding spots define at least four welding spot lines arranged distributed over a circumference of the outer circumferential surface.

7. The cylinder liner as claimed in claim 4, wherein the individual welding spots of the plurality of welding spots are provided at crossing points of individual wires of the at least one of the wire mesh and the wire grid.

8. The cylinder liner as claimed in claim 1, wherein the cast material of the engine block is composed of a light metal.

9. An engine block for an internal combustion engine, comprising: an integrally cast cylinder liner composed of a gray cast iron defining an outer circumferential surface, wherein the cylinder liner is arranged in a cast material; a bonding component disposed between the outer circumferential surface and the cast material and extending at least in part peripherally around the outer circumferential surface, the bonding component having a melting point higher than a melting point of the cast material, wherein the bonding component includes at least one of a wire mesh and a wire grid; wherein the bonding component is connected to the outer circumferential surface via a spot-welded connection, the spot-welded connection including a plurality of welded spots arranged along an axial direction of the cylinder liner to define at least two axially extending welded spot lines distributed circumferentially around the outer circumferential surface.

10. A method for producing an engine block for an internal combustion engine comprising: preparing a cylinder liner of a gray cast iron defining an outer circumferential surface for casting into a cast material, and positioning a bonding component at least in a predefined region on the outer circumferential surface wherein the bonding component includes at least one of a wire mesh and a wire grid for strengthening a bond of the cylinder liner to the cast material, stretching the bonding component over the outer circumferential surface of the cylinder liner, welding the bonding component to the outer circumferential surface of the cylinder liner via a plurality of weld spots, positioning the cylinder liner together with the bonding component into a casting mold of the casting material, filling the casting mold with a light metal alloy thereby producing the engine block while at the same time integrally casting the cylinder liner.

11. The engine block as claimed in claim 9, wherein the bonding component is composed of steel.

12. The engine block as claimed in claim 9, wherein the bonding component is stretched over the entire outer circumferential surface of the cylinder liner.

13. The engine block as claimed in claim 9, wherein the plurality of welded spots respectively define an undercut between the bonding component and the outer circumferential surface to facilitate anchoring the cylinder liner in the cast material.

14. The engine block as claimed in claim 9, wherein the cast material is composed of a light metal.

15. The cylinder liner as claimed in claim 2, wherein the cast material is composed of at least one of aluminium and an aluminium alloy.

16. The cylinder liner as claimed in claim 4, wherein the plurality of welding spots are arranged in an axial direction of the outer circumferential surface.

17. The cylinder liner as claimed in claim 4, wherein the respective welding spots define at least one linear welding spot line extending in an axial direction of the outer circumferential surface.

18. The cylinder liner as claimed in claim 4, wherein the plurality of welding spots respectively define an undercut disposed between the bonding component and the outer circumferential surface to facilitate anchoring the cast material at the welded connection.

19. The method as claimed in claim 10, wherein welding the bonding component to the outer circumferential surface includes forming an undercut at the plurality of weld spots between the bonding component and the outer circumferential surface to facilitate anchoring the cylinder liner in the cast material.

20. The method as claimed in claim 10, wherein welding the bonding component to the outer circumferential surface includes forming a weld spot line by arranging the plurality of weld spots linearly with respect to one another at least one of along an axial direction of the cylinder liner and obliquely to a longitudinal axis of the cylinder liner.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 schematically shows two cylinder liners formed according to the invention in an engine block,

(3) FIG. 2 schematically shows a sectional representation in the region of a welding spot connecting a wire mesh to the cylinder liner,

(4) FIG. 3 schematically shows individual method steps of a method for producing an internal combustion engine.

DETAILED DESCRIPTION

(5) As shown in FIG. 1, a cylinder liner 1 according to the invention has at least in certain regions on an outer circumferential surface 2 a means 3 for strengthening the bond of the cylinder liner 1 to a cast material of an engine block 4. The means 3 is formed here as a wire mesh or wire grid that does not melt during the casting operation of the engine block 4 and preferably consists of steel. A connection of the means 3 to the outer lateral surface 2 of the cylinder liner 1 takes place in this case by way of a welded connection, in particular by way of a number of welding spots 5. The means 3, that is to say the wire mesh or the wire grid, is also stretched over the outer circumferential surface 2 of the cylinder liner 1, whereby close bearing or pressing of the means 3 against the cylinder liner 1 alongside the welding spots 5 can also be achieved. As can be seen from FIG. 1, the means 3 may surround the outer lateral surface 2 of the cylinder liner 1 over its full circumference (compare the cylinder liner on the right in FIG. 1) or else only be provided partially (compare the cylinder liner on the left in FIG. 1).

(6) The individual welding spots 5 of the spot-welded connection are preferably formed linearly here, in particular in the axial direction of the cylinder liner 1, as represented for example in particular in the case of the cylinder liner as shown on the left in FIG. 1. In addition, the individual welding spots 5 of the spot-welded connection are preferably provided at crossing points of the individual wires of the wire mesh or the wire grid, that is to say of the means 3. If the outer lateral surface 2 of the cylinder liner 1 is only partially provided with the means 3, that is to say with the wire mesh or the wire grid, the welding spots 5 are preferably arranged along a starting edge 6 and an ending edge 7, whereby optimal stretching of the means 3 between the two edges 6, 7, and consequently close bearing of the means 3 against the outer lateral surface 2 of the cylinder liner 1 between the two edges 6 and 7, can be achieved. Along the starting edge 6 and along the ending edge 7, the welding spots 5 are arranged here in the axial direction of the cylinder liner 1, and thereby form what are known as welding spot lines 8. In the case of a means 3 that covers the outer lateral surface 2 more than just partially, a number of such welding spot lines 8, distributed in the circumferential direction, may be provided on the outer lateral surface 2, at least 4, preferably 8, welding spot lines 8 being arranged in the axial direction of the cylinder liner 1. Along the individual welding spot lines 8, all of the crossing points of the wires of the wire mesh or wire grid may be welded here to the cylinder liner 1, while it is also conceivable that only every second or third crossing point is welded on.

(7) Apart from a strictly axial alignment of the individual welding spot lines 8, an oblique alignment of the welding spot lines 8 or else an arbitrary punctiform welding of the means 3 onto the cylinder liner 1 is of course also conceivable. However, the welding spot lines 8 extending in the axial direction offer the advantage that the tensioning of the means 3 between two adjacent welding spot lines is equal, since the distance between the individual welding spots 5 of two adjacent welding spot lines 8 is always equal.

(8) After arranging and securely welding the means 3 on the outer lateral surface 2, the cylinder liner 1 according to the invention is placed into a casting mold for casting the engine block 4, the cylinder liner 1 subsequently being encapsulated by the cast material of the engine block 4, for example a light metal, in particular aluminum. Undercuts 9 (compare FIG. 2) thereby form at the welding spots 5, making a particularly secure connection and particularly secure anchoring of the cylinder liner 1 in the cast material of the engine block 4 possible. A better thermal bond of the cylinder liner 1 to the engine block 4 is also achieved by the means 3, that is to say by the wire mesh or by the wire grid, whereby the individual cylinders can be cooled better and, in particular, a distance between two cylinder liners 1, that is to say between two cylinders, can be reduced, whereby the production of a particularly compact, small and therefore also lightweight engine block 4 can be realized. Such a compact engine block 4 in turn allows the weight of an internal combustion engine 10 fitted with it to be reduced, which leads to a not inconsiderable fuel saving when such an internal combustion engine 10 is used in a motor vehicle.

(9) As shown in FIG. 3, a method according to the invention for producing the engine block 4 or the internal combustion engine 10 with such an engine block 4 is now described. In this case, firstly, in a method step A, a cylinder liner 1 of gray cast iron is provided at least in certain regions on its outer circumferential surface 2 with a wire mesh or a wire grid, that is to say a means 3 for strengthening the bond of the cylinder liner 1 to a cast material of the engine block 4. In method step B, this means 3 is subsequently stretched over the outer circumferential surface 2 of the cylinder liner 1. In method step C, the means 3 is welded at least in certain regions to the cylinder liner 1, for example by way of welding spots 5 arranged along the welding spot lines 8, as represented by FIGS. 1 and 2. In method step D, the cylinder liner 1 is then placed together with the means 3 welded thereto into a casting mold for an engine block 4, whereupon, in method step E, the casting mold is subsequently filled with a light metal alloy, in particular with an aluminum alloy, and the engine block 4 is thereby produced while at the same time integrally casting the cylinder liner(s) 1.

(10) With the method according to the invention and with the engine block 4 according to the invention, a much closer arrangement of the individual cylinder liners 1, and as a consequence a much closer arrangement of the individual cylinders in the engine block 4, can be achieved, whereby the engine block can be built smaller, and in particular also lighter. During the casting of the engine block 4, the undercuts 9 that are formed particularly at the welding spots 5 are encapsulated by the cast material of the engine block, and thus produce an extremely secure connection between the cylinder liner 1 and the engine block 4. The close bond of the cylinder liner 1 to the engine block 4 also has the effect in particular of avoiding air gaps between these components 1, 4, which may lead to reduced heat transmission, whereby better cooling and at the same time also a closer arrangement of the individual cylinders are made possible.