DE102010025286B4 - Light metal casting for an internal combustion engine - Google Patents

Abstract

The invention relates to a light metal casting for an internal combustion engine having a channel (101, 106) produced in the course of casting the light metal casting, which is curved or branched one or more times and flows through the exhaust gas (G) which is hot in practical use of the internal combustion engine. In order to effectively prevent the risk of overheating of the light metal surrounding the hot exhaust gas flow channel in such a light metal casting without massive cooling of the exhaust gas being required, the invention proposes that the inner surfaces (110) of the channel (101, FIG. 106) are at least partially occupied by a coating (111) which is formed of a glass material whose melting temperature is greater than the maximum temperature of the exhaust gas (G) and at most equal to the melting temperature of the light metal melt from which the light metal casting is cast.

Description

The invention relates to a light metal casting for an internal combustion engine, which has a channel produced in the course of casting the light metal casting, which is one or more curved or branched and flows through the hot in practical use of the internal combustion engine exhaust gas. Such light metal castings are typically cylinder heads cast from an aluminum alloy, or the housings of turbochargers driven by exhaust gas exiting an internal combustion engine.

Modern concepts for internal combustion engines with two or more cylinders provide that two or more cylinders associated outlets of the internal combustion engine are combined to form an integrated exhaust manifold within the cylinder head to an overall exhaust line, to be subsequently passed to a driven by the exhaust gas stream of the engine functional part. In order to ensure the central discharge of the exhaust gas in a space-saving manner, the integrated exhaust gas line in the cylinder head has a complex shape with usually two laterally leading away from a central connector at a right angle line arms and turn branching off at an angle to the respective outlet openings of the combustion chambers of the internal combustion engine leading line pieces. An example of such an integrated concept is in the EP 2 143 926 A1 described.

The advantage of a common exhaust pipe integrated in the cylinder head consists primarily in that a functional element driven by the exhaust gas stream and required for the operation of the internal combustion engine can be positioned very close to the outlets of the cylinder head. This leads, in particular, when the functional element is a turbocharger, to the fact that the hot exhaust gas between its exit from the combustion chamber of the respective cylinder and the inlet into the exhaust-driven functional element is exposed to only minimal enthalpy losses, so that a particular fast response of the respective functional element is ensured. At the same time is achieved by minimizing the distance between the functional element and the outlets of the engine that the exhaust gases on leaving the exhaust-driven functional element with still high temperature in the subsequent flow through systems for exhaust aftertreatment occur. In this way, there is also quickly reached an operating temperature at which these systems are effective.

An even further integration is in the EP 2 143 922 A1 been proposed. From this publication, a cylinder head with an integrated overall exhaust line emerges, in which the cylinder head, the exhaust manifold and at least parts of the turbocharger or parts of the one- or multi-part turbocharger housing are cast in one piece. The advantage of this integrated casting design of the cylinder head and parts of the turbocharger is seen in the fact that the turbocharger can be arranged even closer to the exhaust valves of the cylinder head, as in a separate production and subsequent assembly of the charger housing to the cylinder head. As a result, the heat-emitting surface and the volume of the channels from the cylinder to the turbocharger should be significantly reduced. This has the consequence that the exhaust gas on its way to the turbocharger suffers only comparatively low enthalpy losses, whereby a faster response of the turbocharger z. B. to be achieved during load changes.

Regardless of whether the turbocharger housing is cast on the cylinder head or not, there is the problem in the above-described integrated designs of a cylinder head that the cylinder head and the turbocharger housing are exposed to very high temperatures in the region of their exhaust-carrying channels. Therefore, in the above-described known concepts, both the common exhaust pipe integrated into the cylinder head and the housing of the turbocharger are cooled by a water jacket also integrated into the cylinder head and the turbocharger housing. Through this, the channel carrying the hot exhaust gas is at least partially cooled. In this way, the exhaust gas temperature is lowered, so that despite the close connection of the turbocharger to the outlet of the cylinder head thermal overload is avoided. However, this measure is counterbalanced by the desire to keep the temperature of the exhaust gas flowing into and out of the turbocharger as high as possible in order to activate the exhaust gas treatment systems subsequently flown through as quickly and effectively as possible.

Against the background of the prior art described above, the object of the invention to provide a light metal casting for an internal combustion engine, in which the risk of overheating of the light metal, which surrounds the hot exhaust gas flow channel is effectively prevented, without causing a massive Cooling of the exhaust gas is required.

This object has been achieved by a light metal casting, which has the features specified in claim 1. Advantageous embodiments of the invention are specified in the dependent claims and are in the following as the general inventive concept explained in detail.

According to the invention, in a light metal casting for an internal combustion engine with a generated in the course of casting the light metal casting channel, which is one or more curved or branched and flows through the hot in practical use of the engine exhaust gas, the inner surfaces of the channel at least partially with a coating occupied, which is formed of a glass material whose melting temperature is at most equal to the melting temperature of the light metal melt from which the light metal casting is cast.

According to the invention, therefore, a glass coating is applied, at least in the regions of the exhaust-carrying channel of a light metal casting element, which are exposed in practical use to particularly high thermal loads. This glass coating forms an insulation, by which the heat transfer from the hot gas to the light metal surrounding the channel is prevented.

Surprisingly, it has been found that the insulating effect of the present invention applied to the inner surfaces of an exhaust gas duct glass layer is so large that the risk of thermal overloading of the light metal compared to identically designed castings, in which no inventive coating is present, even then reduced to a minimum is, if it is in the exhaust-carrying channel is a cylinder head, in which an exhaust manifold is integrated in the of the type described above. By having a coating according to the invention in such a cylinder head on at least one inner surface of an exhaust gas duct, the thermal load of the light metal material can be determined with regard to the load capacity and service life of the light metal material, in particular in such a light metal casting, despite the arrangement of outlet and exhaust gas duct in a confined space Component be maintained level.

The same applies if the light-metal casting is a complex-shaped housing for an exhaust-operated functional component of an internal combustion engine, in which a channel carrying the exhaust gas is cast by casting, which is provided with the coating at least in sections.

The effects achieved by the invention have a particularly positive effect when the light-metal casting according to the invention is a cylinder head with a housing or housing part of an exhaust-operated functional component cast integrally thereon, wherein an exhaust duct connecting the functional component and an exhaust outlet of the cylinder head into the cylinder head is formed, which is at least partially provided with the coating. Especially with the narrow spatial conditions, as given in such a cylinder head functional component combination, the thermal insulation achieved by the coating according to the invention proves to be particularly favorable.

Typically, the functional component mentioned above is an exhaust gas driven turbocharger.

The advantages of the coating according to the invention can also be used particularly well in complicated castings because the coating according to the invention can be produced in a particularly simple manner in the course of the casting production of the light metal casting. For this purpose, the properties of the glass material from which the coating according to the invention, so on the cast material from which the light metal component is cast, and matched during operation temperatures of the channel coated in accordance with the invention channel flowing hot exhaust gas tuned that the glass material at Contact with the cast material melts automatically, but at the same time is so temperature-resistant that it retains its insulating effect even with an intense flow through the hot gas. For this purpose, the glass material, from which the coating produced according to the invention consists, has a melting temperature which is greater than the maximum temperature of the exhaust gas and at most equal to the melting temperature of the light metal melt from which the light metal casting is cast.

The glass material used according to the invention may be a glass solder whose melting temperature is in the range of 360-600 ° C., in particular 480-550 ° C.

The glass material obtained according to the invention in the above-described manner is applied to the casting core or cores, for example in the form of a powder or granules, prior to the casting of the light metal casting, which or which image port the respective exhaust channel in the casting to be cast. As soon as the powdered or granular glass material comes into contact with the hot, molten light metal melt during the casting of the casting, it begins to soften and melt on further contact with the now solidifying casting. It is an intimate bond with the surface of the casting. As the cooling progresses, the glass material also solidifies again, with the inner surface of the respective exhaust gas leading to it Channel of the light metal casting forming surface sticks. In this way, a coating according to the invention can be safely generated at remote, hard to reach places, without the need for additional aids. The invention thus uses the itself, for example, from the DE 37 15 198 C2 for a known from cast iron boiler possibility to provide hard to reach places of a casting by a glass coating that the glass material in question applied to a casting core and is transmitted from there during the casting of the casting metal on the casting.

Unlike the prior art, however, the invention uses this type of coating for castings for internal combustion engines made of light metal. In these components, the exhaust ducts are particularly filigree. Also, the thermal loads occurring in practical use are different than in a boiler of the art coated according to the prior art. Thus coated according to the invention light metal castings are not only in the heating from the cold state ("cold start") thermal stress, but also high frequency with comparable Low amplitudes changing temperature fluctuations, which occurs due to the irregular load changes occurring during operation.

For example, by selecting a glass material with a suitable melting temperature range or a certain distribution of the glass powder or granules on the respective casting core, the structure of the coating formed on the inner surface of the exhaust gas according to the invention can be influenced. Thus, it is possible to form the coating according to the invention with a closed structure extending over the respectively coated section. This may be useful, for example, if the thermal expansion behavior of the glass material used corresponds approximately to the expansion behavior of the light metal from which the respective casting is cast.

A completely closed coating will ensure an optimal insulating effect in the majority of applications.

If it turns out that the stresses occurring in the coating as a result of the operational heating become so great that it threatens to rupture a coating formed in a closed manner from the respectively coated surface, then it may be expedient to provide the coating with at least one predetermined separation point the coating is divided into two or more areas. This allows the individual areas of the coating to move relative to one another, so that high stresses in the coating are avoided.

It is particularly effective in minimizing thermally induced stresses in the coating when the coating is formed by individually self-contained glass beads adhered in one or more groups close to or isolated from the inner surface of the channel provided with the coating. This feature of the coating has the advantage that the glass beads individually, d. H. without being firmly bonded to adjacent glass beads, or in groups whose glass beads are firmly connected to each other but which have no connection with the surrounding glass beads, are present, so that a plurality of predetermined separation points are present and the coating optimally with its heating or Cooling accompanying changes in the dimensions of the light metal casting can follow. A coating with a pearl-shaped structure as explained above can be produced, for example, by choosing a glass material with a melting point for the coating which is very close to the melting temperature of the respectively cast light metal melt. If such a glass material is added to a core as a powder or granules which images the exhaust gas channel in the light metal casting to be cast, the individual glass material grains only melt on contact with the melt to such an extent that spatially enclosed pearl-shaped structures are formed. These retain their self-contained shape without merging with a larger quantity of adjacent beads to form a laminar layer. Of course, it may happen that two or more closely spaced grains together form a bead of larger volume. Optimally, this structure is then retained in itself, without forming a closed coating with other adjacent beads. However, it can naturally also happen that in certain areas in which there is a particularly high heat input through the melt, a two-dimensional coating forms, while in another area the above-described pearly structure is formed.

Alloys of the classes AlSiCu, AlSiMg or AlCu, whose melting temperature is in the range of 560-670 ° C., are typically used as the casting material for the light metal components in question.

The invention will be explained in more detail with reference to an embodiment. Each show schematically:

1 a section of a permanent casting according to 2 Cast cylinder head in one of the 3 corresponding sectional view.

2 a permanent mold for casting a cylinder head for an internal combustion engine in a perspective view;

3 a section of the permanent mold according to 2 in a section along the in 2 indicated section line XX.

In the in 1 Only shown in a cutout cylinder head 100 is an exhaust duct 101 integrated, according to the in the EP 2 143 926 A1 Development described here not visible exhaust outlets of the combustion chambers of the internal combustion engine, on which the cylinder head 100 is mounted, together to an outlet opening 102 leads. Around the exhaust duct 101 Cooling surrounding material is the exhaust channel 101 surrounded by a water jacket of which at the in 1 selected representation each have an upper area 103 and a lower area 104 is visible.

In addition, the cylinder head 100 with a housing molded to it in one piece 105 for a turbocharger not shown here combined. In the case 105 is an exhaust duct 106 molded, starting from the outlet opening 102 the integrated exhaust duct 101 of the cylinder head 100 spirally wrapped to an outlet opening 107 leads, whose longitudinal axis transverse to the inflow direction E of the exhaust passage 106 aligned flowing hot exhaust gas flow and in the later sits the impeller of the turbocharger. The exhaust duct 106 of the housing 105 is like the exhaust duct 101 of the cylinder head 100 from a water jacket 108 surrounded by a dividing wall 109 from the exhaust duct 105 is separated and the course of the exhaust duct 106 following spirally shaped. With one end is the water jacket 108 of the housing 105 to the upper area 103 the water jacket channel of the cylinder head 100 connected while holding his lower end to the lower area 104 the water jacket channel of the cylinder head 100 connected is. This is also the case 105 integral part of the cylinder head 100 , its water jacket channel and exhaust duct 101 jump into the water jacket 108 or the exhaust duct 106 of the housing 105 pass.

For additional protection against overheating of the aluminum casting material, which in the practical use of a hot exhaust gas flow G through the exhaust ducts 101 . 106 from cylinder head 100 and housing 105 surrounds, these are the exhaust ducts 101 . 106 delimiting inner surfaces 110 of the cylinder head 100 or of the housing 105 with a coating 111 occupied by a glass material. This glass material is a glass solder having a melting temperature that is, for example, about 60 ° C lower than the melting temperature of the aluminum casting material from which the cylinder head 100 together with the housing 105 is poured.

Dependent on the thermal expansion behavior of the material of the coating and the casting material of cylinder head 100 and housing 105 is the coating 111 formed so that it has a pearly structure which is characterized by individual self-contained glass beads, or forms a continuous, optionally divided by predetermined separation points dense surface. In the areas where the coating 111 Having a pearly structure, it typically reaches a coverage density that is 30-70% of the occupancy density in the area of the inner surface 110 corresponds, which is covered with a flat densely formed coating.

The for simultaneous, one-piece casting of cylinder head 100 and housing 105 provided permanent casting mold 1 is on a backing plate 2 assembled. The carrier plate 2 is for example arranged on a transport system, not shown, which the permanent mold 1 transported to a casting station also not shown here.

The permanent casting mold 1 is made of a molded part usually made of molding sand 3 and composed of several permanent moldings, of which here the permanent moldings 4 . 5 . 6 are visible. This forms the molding 3 the lid, the permanent mold part 4 a first side wall, the permanent mold part 6 a second side wall and the permanent mold part 5 a bottom of the permanent mold 1 , The permanent casting moldings of the permanent casting mold 1 can in known manner consist of a suitable steel, which is so high temperature and wear resistant, that the permanent moldings can be reused for a large number of casting operations.

The permanent casting moldings of the permanent casting mold 1 surround a mold cavity 7 the permanent casting mold 1 towards the surroundings U and point to their mold cavity 7 associated page features 8th . 9 on, through which the outer shape of the cylinder head to be cast 100 is shown.

To those within the cylinder head to be cast 100 Imagine required cavities and channels are in the mold cavity 7 the permanent casting mold 1 a larger number of cores inserted, of which in 2 the cores 10 . 11 . 12 are visible. The mold core 10 forms at the in 2 shown position of the permanent mold 1 the upper area 103 of the water jacket channel to pouring cylinder head 100 down, while the mold core 11 the lower area 104 this water jacket channel forms. The distance between the cores 10 . 11 arranged mold core 12 On the other hand, it forms the cylinder head to be cast 100 integrated exhaust duct 106 from.

In the one side wall of the permanent mold 1 forming permanent casting molding 5 is starting from the edge of which the lid of the permanent mold 1 forming molding 3 is assigned, an opening 13 formed, which extends in the direction of the opposite edge. The cores 10 . 11 . 12 are each designed so that they are at the opening 13 ends or in the opening 13 the permanent casting mold 1 protrude.

The width of the opening 13 is at the same time sized to give you a head start 20 a form package 21 receives that on the outside of the permanent molding 6 is arranged. This lead 20 of the mold package 21 fills the opening 13 the permanent casting mold 1 completely off and lies with its laterally over the projection 20 going beyond, the permanent mold part 6 associated wall surfaces close to the outer surface of the permanent molding 6 at.

The split in the vertical direction in the present embodiment mold package 21 is made of several moldings 22 . 23 and cores 24 . 25 composed, which are each prepared in a conventional manner from a per se also known, mixed with a suitable binder molding sand.

The molding 22 forms one half of the block-shaped in the assembled state form package 21 while the other half of the mold package 21 through the molding 23 is formed. The moldings 22 . 23 enclose a mold cavity section 26 in which the cores form 24 . 25 are arranged and in the area of the front side of the opening 13 the permanent casting mold 1 sitting tab 20 to from the permanent mold parts 4 - 6 limited mold cavity 7 is open.

The mold package 21 serves for simultaneous one-piece casting of the housing 105 for the exhaust-driven, water-cooled turbocharger to the in the permanent mold 1 to be cast cylinder head 100 , The one mold core 24 of the mold package 21 forms the water jacket 108 of the housing to be cast 105 from. For this purpose, the mold core 24 a curved in the manner of a spiral or a screw shape. That in the representation in 2 lower end 27 of the mold core 24 is so positioned and shaped that this end at the permanent mold part 6 sitting mold package 21 with its front surface over the entire surface flush and accurate position on the associated end face of the mold core 11 rests on the lower part of the water jacket of the cylinder head to be cast 100 maps.

Starting from this end 27 the mold core is running 24 in a narrowing spiral upwards. At his at the presentation in 2 upper, the inner end of the mold core 24 formed spiral forming end portion 28 is one in the direction of the mold cavity 7 prominent projection 29 educated. Its end face is in turn positioned and shaped so that it is at the permanent mold part 6 sitting mold package 21 flush with the entire surface and accurately positioned on the associated end face of the mold core 10 is present, the in the representation according to 1 upper area 103 the water jacket of the cylinder head to be cast 100 maps.

The second mold core 25 of the mold package 21 forms the flue gas channel, which in use is hot exhaust gas 106 of the housing 105 from. He sits in the of the mold core 24 bounded space and also has a snail-like shape. His in the presentation in 3 lower end section 30 is positioned and shaped in such a way that its end surface is flush with its end face of the mold core 12 abuts the integrated exhaust duct 106 of the cylinder head to be cast 100 maps. Starting from the lower end section 30 goes the mold core 25 the contour of the mold core 24 following in a formed at its other end, peg-shaped projection 31 about, whose longitudinal axis L is usually parallel to the flat outer surface of the permanent mold part 6 extends. The lead 31 sits with its free end positively in a correspondingly shaped, not visible here recess of the molding 22 and forms on the housing to be cast 105 the outlet opening 107 from.

Both between the mold cavity section 26 delimiting inner surfaces 32 the molded parts 22 . 23 and the outer surface facing them 34 of the mold core 24 as well as between the inner, the mold core 25 facing surface 35 of the mold core 24 and the mold core 24 facing peripheral surface 36 there is always a substantially constant distance. Accordingly, in the mold cavity section 26 of the mold package 21 a first spiral outer channel 38 and separated therefrom, a second also spiral inner channel 37 educated. Both channels 37 . 38 are at on the permanent mold 6 mounted mold package 21 with their one as with their other end each uninterruptible with a free, not occupied by mandrels area of the mold cavity 7 the permanent casting mold 1 connected.

To the cylinder head 100 and the housing cast on it 105 on the inner surfaces of the through the cores 25 and 12 illustrated, in practical use hot exhaust gas leading exhaust gas ducts the coating 111 to form are the mandrels 12 and 25 occupied with glass solder powder P. Quantity, density and area in which the glass solder powder is applied, are chosen so that at the with the coating 111 occupied surface sections of the exhaust ducts 101 . 106 the optimum structure of the coating there 111 established.

Will the mold cavity 7 the permanent casting mold 1 filled in a conventional manner via a casting system not shown here with aluminum melt, so the melt flows on reaching a certain filling levels without interruption in the channels 37 . 38 of the mold package 21 until they are completely filled as well.

After solidification of the melt and demolding the then finished cast cylinder head 100 this forms in the outer channel 38 Accordingly, light metal solidified the outer wall of the one-piece to the cylinder head 100 cast housing for the turbocharger, while in the channel 37 solidified material through the mold core 24 pictured water jacket of the turbocharger housing opposite to that through the mold core 25 delimited illustrated exhaust duct of the turbocharger.

The demolding of the cylinder head 100 cast-on turbocharger housing takes place in a conventional manner characterized in that the moldings 22 . 23 and the cores 24 . 25 be destroyed by the action of external forces. This can be done, for example, by shaking the cylinder head 100 done as is usually done to those in the mold cavity 7 sitting mandrels 10 - 12 to destroy and from the finished cylinder head 100 let it trickle out.

To a tailor-made, correct position alignment of the mold package 21 in the opening 13 and on the permanent mold part 6 as well as a clear positionally correct assignment of the mandrels 10 - 12 and 24 . 25 to ensure, on the parts in question molded elements, such as projections 39 and correspondingly shaped recesses 40 be formed, the composite with continuous casting mold 1 cooperate positively and thus ensure that the associated parts also under the casting process or during transport of the permanent mold 1 occurring forces to maintain their position.

The correct orientation of the mold package 21 on the permanent mold part 6 or in the opening 13 In addition, it can also be supported by the fact that the opening 13 surrounding edge surface portions at least in the region of 2 lower edge surface 14 starting from her the mold cavity 7 associated edge in the direction of the outer surface of the permanent mold part 6 so beveled is that the opening 13 at least in this area in the direction of the environment U widened in the manner of a funnel, the opening 13 in the direction of the mold cavity 7 so narrowed conically. By the thus bevägten portion of the edge surface 14 associated surface portion of the projection 20 of the mold package 21 beveled in a corresponding manner, centered the mold package 21 in his finished on the permanent mold part 6 positioned position at least in the direction of the height of the permanent mold 1 automatically.

On the support plate 2 is the mold package 21 by a buck 41 supported. Alternatively, in the carrier plate 2 be formed in a conventional manner, a core mark on which the mold package 21 in terms of its position relative to the associated permanent mold part 6 is positively fixed.

The presently explained design of the cylinder head 100 and the housing cast on it 105 is to be understood only as an example, since with appropriate design and effectiveness of the coating 111 the volume of the water jackets 103 . 104 . 108 from cylinder head 100 and housing 105 reduced or additional water cooling at least partially can be completely dispensed with.

LIST OF REFERENCE NUMBERS

100

cylinder head

101

Exhaust duct of the cylinder head 100

102

Outlet opening of the cylinder head 100

103

Upper area of the water jacket of the cylinder head 100

104

lower area of the water jacket of the cylinder head 100

105

to the cylinder head 100 molded housing

106

Exhaust duct of the housing 105

107

Outlet opening of the exhaust duct 106

108

Water jacket of the housing 105

109

Partition wall of the housing 105

110

Inner surfaces of the exhaust ducts 101 . 106

111

Coating of glass material

1

permanent mold

2

support plate

3

molding

4-6

Dauergießformteile

7

mold cavity

8, 9

form elements

10-12

mandrels

13

opening

14

Edge surface of the opening 13

20

head Start

21

mold package

22, 23

moldings

24, 25

mandrels

26

Mold cavity section

27

End of the mold core 24

28

End portion of the mold core 24

29

Projection of the mold core 24

30

End portion of the mold core 25

31

Projection of the mold core 25

32

Inner surfaces of the moldings 22 . 23

34

outer surface of the mold core 24

35

inner surface of the mold core 24

36

Peripheral surface of the mold core 25

37

Channel of the mold package 21

38

Channel of the mold package 21

39

projections

40

recesses

41

buck

e

Inflow direction of the exhaust gas flow G.

G

exhaust gas flow

L

longitudinal axis

P

Glaslotpulver

U

Surroundings

Claims (10)

Light metal casting for an internal combustion engine with a channel produced during the casting of the light metal casting ( 101 . 106 ), which is one or more curved or branched and flows through the hot exhaust gas (G) in the practical use of the internal combustion engine, characterized in that the inner surfaces ( 110 ) of the exhaust duct ( 101 . 106 ) at least in sections with a coating ( 111 ), which is formed of a glass material whose melting temperature is greater than the maximum temperature of the exhaust gas (G) and at most equal to the melting temperature of the light metal melt from which the light metal casting is cast. Light metal casting according to claim 1, characterized in that the glass material is a glass solder. Light metal casting according to claim 2, characterized in that the melting temperature of the glass solder in the range of 360-600 ° C, in particular 480-550 ° C, is located. Light metal cast part according to one of the preceding claims, characterized in that the coating ( 111 ) a closed, over the respective coated section of the exhaust passage ( 101 . 106 ) has extending structure. Light metal casting according to one of claims 1, 2 and 3, characterized in that the coating ( 111 ) has at least one predetermined separation point through which the coating ( 111 ) is divided into two or more areas. Light metal casting according to claim 5, characterized in that the coating ( 111 ) is formed by individually self-contained glass beads in one or more groups close together or isolated at the with the coating ( 111 ) provided inner surface ( 110 ) of the exhaust duct ( 101 . 106 ) be liable. Light metal cast part according to one of the preceding claims, characterized in that it has a cylinder head ( 100 ) and the glass coating ( 111 ) on at least one inner surface ( 110 ) of a casting-produced exhaust gas channel ( 101 ) of the cylinder head ( 100 ) is available. Light metal cast part according to one of claims 1 to 6, characterized in that it has a housing ( 105 ) for an exhaust-operated functional component, in which an exhaust gas duct channel leading the exhaust gas (G) ( 106 ) is shown by casting, the at least partially with the coating ( 111 ) is provided. Light metal casting according to one of claims 1 to 6, characterized in that it is a cylinder head ( 100 ) with an integrally molded housing ( 105 ) or housing part of an exhaust-operated functional component, and that in the cylinder head ( 100 ) a functional component and an outlet opening ( 102 ) of the cylinder head ( 100 ) connecting exhaust duct ( 101 ) formed at least in sections with the coating ( 111 ) is provided. Light metal casting according to claim 8 or 9, characterized in that the functional component is a housing ( 105 ) of a turbocharger.

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