EP2905455B1 - Method for coating a bore and cylinder block of an internal combustion engine - Google Patents

Method for coating a bore and cylinder block of an internal combustion engine Download PDF

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Publication number
EP2905455B1
EP2905455B1 EP15153047.4A EP15153047A EP2905455B1 EP 2905455 B1 EP2905455 B1 EP 2905455B1 EP 15153047 A EP15153047 A EP 15153047A EP 2905455 B1 EP2905455 B1 EP 2905455B1
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EP
European Patent Office
Prior art keywords
bore
enamel coating
coating
enamel
cylinder block
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP15153047.4A
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German (de)
French (fr)
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EP2905455A3 (en
EP2905455A2 (en
Inventor
Carsten Weber
Jan Mehring
Kai Kuhlbach
Urban Morawitz
Maik Broda
Clemens Maria Verpoort
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Ford Global Technologies LLC
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Ford Global Technologies LLC
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Publication date
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Publication of EP2905455A2 publication Critical patent/EP2905455A2/en
Publication of EP2905455A3 publication Critical patent/EP2905455A3/en
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Publication of EP2905455B1 publication Critical patent/EP2905455B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/18—Other cylinders
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
    • B05D3/0254—After-treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/12—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by mechanical means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23D—ENAMELLING OF, OR APPLYING A VITREOUS LAYER TO, METALS
    • C23D5/00—Coating with enamels or vitreous layers
    • C23D5/005—Coating with enamels or vitreous layers by a method specially adapted for coating special objects
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/18—Processes for applying liquids or other fluent materials performed by dipping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/22—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23D—ENAMELLING OF, OR APPLYING A VITREOUS LAYER TO, METALS
    • C23D5/00—Coating with enamels or vitreous layers
    • C23D5/02—Coating with enamels or vitreous layers by wet methods
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B77/00—Component parts, details or accessories, not otherwise provided for
    • F02B77/02—Surface coverings of combustion-gas-swept parts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2253/00—Other material characteristics; Treatment of material
    • F05C2253/12—Coating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49229—Prime mover or fluid pump making
    • Y10T29/49231—I.C. [internal combustion] engine making

Definitions

  • the present invention relates to a method for producing a coated surface, in particular a cylinder bore of an internal combustion engine, and a cylinder block of an internal combustion engine.
  • the FR 2 179 305 A5 discloses a method for applying a layer of liquid anti-rust compound on the inner surfaces of pipes and an apparatus for performing the method.
  • Cylinder bores in internal combustion engines should have an even and slight play between their inner circumference and pistons or piston rings that move back and forth therein, ideally achieving ideal tribological conditions.
  • the DE 10 2007 023 297 A1 discloses that a two-stage method is to be provided, with a finishing being to follow a pre-processing.
  • a two-stage method is to be provided, with a finishing being to follow a pre-processing.
  • the second step towards the production of a non-circular starting form is started, i.e. before the fine machining is started, she sees DE 10 2007 023 297 A1 before applying a sliding layer on the pre-processed initial shape.
  • This can be done according to the DE 10 2007 023 297 A1 only with a thermal spraying process, whereby one considers arc wire spraying, atmospheric plasma spraying or high-speed flame spraying.
  • Plasma powder spraying can also be a suitable spraying method.
  • the DE 10 2007 023 297 A1 in particular that the layer thickness of the applied layer should not be less than at least 50 ⁇ m.
  • the surface should be pretreated thermally, mechanically, chemically or with a water jet before coating.
  • Thermal spray processes can be used to produce tribologically suitable wear protective layers.
  • such coatings are not used in practice for engine blocks made of gray cast iron material (GG material) because the honed GG surface itself is already well suited tribologically due to the graphite lamellae with their self-lubricating effect. Therefore, in GG engine blocks, worn raceways in particular are restored to their original condition by spraying on steel layers. The original diameter can then be set again by honing.
  • Such thermally spray-repaired engines are known to have a lower oil consumption or higher output than engines that have been repaired by spinning out the bore and using oversized pistons. This results in a further reduced friction between the piston ring and the porous thermal spray layer, the pores acting as an oil reservoir and providing additional oil for the piston ring, particularly in the area of the piston reversal points and thus in the area of the mixed friction.
  • thermal spray coatings show a weak point, for example with regard to the problem of sub-corrosion, e.g. if aggressive, contaminated fuels are used.
  • highly Cr-alloyed powders or wires as a filler material for thermal spray coating, which further increases the manufacturing costs.
  • condensates or acids can still attack the base material through the layer.
  • under-corrosion problems can only be prevented by additional impregnation of the layers.
  • thermal powder coatings for Zr-O2 with yttrium oxide stabilization can be used to produce thermal insulation layers for internal combustion engines or gas turbines.
  • Such plasma powder spray coatings are characterized by low heat conduction even at very high temperatures up to over 1100 ° C.
  • plasma powder spray layers cannot be mechanically loaded, such thermal insulation layers would not be suitable as a tribologically stressed coating in the cylinder race.
  • the invention is based on the object of advantageously developing a method of the type mentioned at the outset.
  • the enamel coating applied to the inner surface of the bore has particularly good thermal insulation properties and particularly good tribological properties. Undercorrosion is also reliably avoided, and costly additives such as zirconium oxide / yttrium oxide can be dispensed with.
  • a method is purposefully provided in which a suitable coating fulfills all requirements for a reliable function of the component with minimal manufacturing costs, the method according to the invention simultaneously but can also be integrated into the existing production chain for the manufacture of the engine blocks without great difficulty.
  • the enamel coating according to the invention is preferably a melt mixture.
  • the glass-forming oxides melt together to form a glass melt.
  • Glass-forming oxides can be SiO 2 , B 2 O 3 , Na 2 O, K 2 O and Al 2 O 3 .
  • Basic emails contain approx. 23 - 34% by weight (weight percent) borax, 28 - 52% by weight feldspar, 5 - 20% by weight quartz, approx. 5% by weight fluoride, as well as the rest of soda and sodium nitrate.
  • the oxides of Ti, Zr and Mo can serve as opacifiers.
  • components of cobalt, manganese or nickel oxides are provided, for example. It is still possible to use ceramic pigments, e.g. Use iron oxides, chromium oxides and spinels.
  • the substances mentioned are finely ground and melted.
  • the melt is quenched, that is to say preferably placed in water, the granular glassy frit thus formed being finely ground again in the subsequent step.
  • 30% to 40% water is added together with clay and quartz powder.
  • the opacifiers and color oxides mentioned are added.
  • an enamel slip is formed, which should rest for a better time, preferably a few days, for better mixing before the enamel slip would be used again.
  • suitable adjusting means ensures that a uniform layer thickness, e.g. after a dip coating, whereby a possible dip coating with a flood device is discussed in more detail.
  • the aqueous enamel slip can be applied by means of a rotating device, which can be moved back and forth in the vertical direction of the bore for rotation about its vertical axis.
  • the device can be designed as a lance, the material being able to be applied in several transitions, that is to say layers.
  • the lance points at least one outlet opening from which the enamel slip can emerge at its end of the order.
  • the enamel slip is thrown onto the surface to be coated.
  • several outlet openings can also be provided, which can be arranged on the lance as seen in the circumferential direction as well as in the vertical direction thereof.
  • a certain thickness of material is first applied, which is then dried before the next layer, that is to say further material, is applied.
  • This layer can be dried with an induction coil, for example.
  • the enamel coating is applied in a single step.
  • the enamel coating can also be applied in one dipping process.
  • the exterior of the cylinder block is inevitably coated, which is disadvantageous in terms of material savings.
  • the bore is flooded with the enamel slip, which is also referred to in the sense of the invention as a diving process with a flooding device.
  • the entire cylinder block is first placed on a flood device with its head side.
  • the flooding device advantageously has at least one chamber which has at least one outlet opening, a feed opening also being provided.
  • a line is connected to the feed opening, which leads the enamel slurry to the flooding device, so that a pressure is created in it, that is to say in the chamber, that the enamel slip enters the bore to be coated from the outlet opening from below.
  • sealing elements are also provided, for example in the configuration as a sealing lip on the flooding device, on which the wall of the bore to be coated can rest in the circumferential direction, so that the bore is sealed off from its wall to the flooding device.
  • the entire bore i.e. the inner surface of the same, is coated with the enamel slip.
  • a multi-stage layer structure with the optional intermediate drying of individual partial layers as well as the application of the enamel coating in one step can be provided.
  • the borehole is flooded from bottom to top. Of course it is possible to flood the hole from top to bottom with the enamel slip. To do this, the email slip is opened in the top Drilled hole, which is also considered a diving process in the sense of the invention.
  • the base body that is to say the cylinder block
  • the sand casting process being suitable as the production method. This is generally known, so it will not be discussed further.
  • the bore that is to say the cylinder bore, is then drilled out and pre-machined, the bore being drilled out to an oversize of 1 to 2 mm in diameter. It is expedient in the sense of the invention if the surface in the area of the bore, ie the inner surface of the bore, is spindled to a roughness of Ra 6 to 7 ⁇ m.
  • the enamel coating is applied.
  • the enamel coatings according to the invention are distinguished from the electroplating or thermal spray coatings by the fact that they cannot be infiltrated.
  • the enamel coating according to the invention cannot be further damaged if the layer is removed down to the base material due to local damage. Rust damage will only occur in the area of the missing enamel layer, but this will not increase further.
  • the enamel coating according to the invention is characterized by good wear resistance due to the high layer hardness of typically 600-800HV0.1. This means that the hardness is three times higher than that of the GG base material.
  • the cylinder block with the dried enamel coating is heated to 800 - 900 ° C in a protective gas oven and held for approx. 10 - 20 minutes. This is followed by rapid cooling, preferably in a molten salt, so that the cylinder block has a significantly higher strength than with conventional GG material.
  • the enamel baking treatment and this heat treatment run in the same temperature-time window, which is used with the invention. In this respect, the enamel baking treatment and this heat treatment are combined, so that this baking and quenching operation results in a cylinder block with increased mechanical strength and a cylinder bore with good thermal insulation and good wear and corrosion resistance.
  • the engine blocks are finished and honed to their final dimensions in the race track.
  • Layer thicknesses of 500-1000 ⁇ m are preferably applied.
  • This thermal insulation results from the use of oxides such as Si, Ti, Ca oxides but also from the typical air bubble inclusions in the solidified glass matrix.
  • This hard and brittle layer is very easy to work with diamond honing stones, whereby these air bubbles are cut and exposed.
  • these are not interconnected pores or pore nests as in the case of a thermally applied spray coating, so that a high hydrodynamic pressure can build up in the pores of the enamel coating according to the invention and the oil film through the piston ring does not connected pores can be pushed away.
  • the method according to the invention is suitable for coating cylinder liners of internal combustion engines.
  • the baking cycle of the enamel coating can be combined with the AGI heat treatment, so that the cylinder block subsequently has a higher strength.
  • the composition of the enamel coating can be adjusted by adding hard carbides so that the wear resistance e.g. can be raised for use in highly charged engines. Compared to Zr oxide powder (currently € 60 / kg and using the expensive powder plasma spray process), wet slurrying of enamels (currently € 2-4 / kg) is very cost-effective.
  • the invention thus provides a method for producing a wear and corrosion coating within the bore of a cylinder block of an internal combustion engine made of gray cast iron material.
  • this coating at least meets the following requirements: due to the low thermal conductivity, it reduces the heat loss in the combustion process and thus allows the heat in the combustion process to be better used thermodynamically in order to achieve a higher degree of efficiency.
  • this coating also has good tribological properties in order to cope with the friction-wear conditions of the piston group. According to the invention, these requirements are met by burning in the hard enamel coating, if necessary.
  • the necessary baking treatment of the enamel coating is combined with the AGI heat treatment, so that only very low costs are incurred for this enamelling and at the same time the cylinder block is given a higher strength than a cylinder block made of conventional GG material. It is also conceivable to provide an aluminum cylinder block, that is to say its cylinder barrel, with the enamel coating.
  • the enamel coating surface can be subjected to a final treatment, i.e. a finish, after the baking step. Provision is preferably made to machine the friction surfaces in a rotating manner and to remove the scale layer which has arisen as a result of the annealing process. It is also possible to rework the hole by regrinding, using diamond or Hard material cup wheels can be used. Post-processing by turning or spinning is conceivable, which is feasible despite the high hardness due to the brittleness, with PCD (polycrystalline diamond) indexable inserts being preferred.
  • a final treatment i.e. a finish
  • Figure 1 shows a method for coating a bore 1 with an enamel coating 2.
  • the bore 1 is made in a cylinder block 3, which is shown in FIG Figure 2 is recognizable. Of the cylinder block 3 is in Figure 1 only the inner surface 4 of the bore 1 can be seen.
  • the cylinder block 3 was produced as a base body 3 in a sand casting process from a gray cast iron.
  • the bore 1 was drilled out to an oversize of 1 to 2 mm in diameter.
  • the surface 4 in the area of the bore 1 was also spindled to a roughness of Ra 6 to 7 ⁇ m.
  • the bore 1 is provided with an enamel coating 2.
  • the enamel coating 2 is in the form of an aqueous enamel slip in the exemplary embodiment Figure 1 by means of a rotating device 6 which at the same time for rotation about its axis in the vertical direction of the bore 2 in the same back and forth is applied.
  • the movement arrows regarding rotation and back and forth are in Figure 1 drawn.
  • the device 6 can be referred to as a lance 6, the material, that is to say the aqueous enamel slip, being able to be applied in several transitions, that is to say layers.
  • a certain thickness of material is first applied, which is then dried before the next layer, that is to say further material, is applied.
  • This layer can be dried with an induction coil, for example.
  • the enamel coating is applied in a single step.
  • the enamel coating 2 can also be applied in a dipping process. Recognizable in Figure 2 is that the bore 1 is flooded with the enamel slurry from below, which is referred to as a dipping process in the sense of the invention. The entire cylinder block 3 is placed with its head side 7 standing on a flooding device 8.
  • the flooding device 8 advantageously has at least one chamber 9 which has an outlet opening 10, a feed opening 11 being provided.
  • a line 12 is connected to the feed opening 11, which leads the enamel slurry to the flooding device 8, so that pressure, such as this, arises in the chamber 9 that the enamel slip enters the bore 1 to be coated from the outlet opening 10 from below.
  • Sealing elements 13, e.g. provided in the embodiment as a sealing lip 13 on the flood device 8, on which the wall 14, that is to say on the end face of the bore 1 to be coated, can bear in the circumferential direction, so that the bore 1 is sealed via its wall 14 to the flood device 8.
  • the entire bore 1, that is to say the inner surface 4 thereof, is thus coated with the enamel slip.
  • a multi-stage layer structure with the optional intermediate drying of individual partial layers as well as the application of the enamel coating in one step can be provided.
  • the internal combustion engine that is to say the cylinder block 3 may have more than one cylinder bore 1, which is within the meaning of the invention.
  • the flood device 8 can also have more than the recognizable one chamber 9, which can be arranged one behind the other and / or next to one another. This depends on the type of internal combustion engine, for example as an in-line engine or as a V-engine.
  • a separate flooding device 8 with a single chamber 9 can also be provided for each bore 1. It is expedient if all the bores 1 are provided with the enamel coating 2 at the same time, which can of course also be done in succession. In terms of heat treatment, however, coating that is as simultaneous as possible is advantageous.
  • the enamel coating being metallurgically bonded to the base material of the bore by phase formation.
  • This post-treatment combines a heat treatment with subsequent quenching.
  • the two treatments i.e. the enamel baking process, as well as the said heat treatment take place in the same temperature-time window, so that this baking and quenching operation results in a cylinder block with increased mechanical strength and a cylinder bore with good thermal insulation and good wear - and corrosion resistance results.
  • the enamel coating 2 can then be subjected to a finish, for example using diamond honing stones.
  • the pores / air bubbles 15 present in the enamel coating 2 are cut and exposed, as in Figure 3 is recognizable.
  • the inner surface 4 of the bore 1, the enamel coating 2 and the transition zone 16 arranged between them can be seen.
  • the pores / air bubbles 15 are not interconnected pores or pore nests as in the case of a thermally applied spray coating, so that a high hydrodynamic pressure can build up in the cut and exposed pores / air bubbles of the enamel coating according to the invention and the oil film cannot be pushed into connected pores by the piston ring.

Description

Die vorliegende Erfindung betrifft ein Verfahren zum Herstellen einer beschichteten Oberfläche, insbesondere einer Zylinderbohrung eines Verbrennungsmotors, sowie einen Zylinderblock eines Verbrennungsmotors.The present invention relates to a method for producing a coated surface, in particular a cylinder bore of an internal combustion engine, and a cylinder block of an internal combustion engine.

Die FR 2 179 305 A5 offenbart ein Verfahren zum Auftragen einer Schicht flüssiger Rostschutzmasse auf die Innenflächen von Rohren und eine Vorrichtung zum Durchführen des Verfahrens.The FR 2 179 305 A5 discloses a method for applying a layer of liquid anti-rust compound on the inner surfaces of pipes and an apparatus for performing the method.

Die US 2 048 912 A befasst sich mit einer Emaille-Spritzvorrichtung.The US 2,048,912 A. deals with an enamel sprayer.

Zylinderbohrungen von Verbrennungsmotoren sollten ein gleichmäßiges und geringes Spiel zwischen ihrem Innenumfang und sich darin hin und her bewegenden Kolben bzw. Kolbenringen aufweisen, wobei bestenfalls ideale tribologische Bedingungen erreicht werden.Cylinder bores in internal combustion engines should have an even and slight play between their inner circumference and pistons or piston rings that move back and forth therein, ideally achieving ideal tribological conditions.

Die DE 10 2007 023 297 A1 offenbart, dass ein zweistufiges Verfahren vorgesehen sein soll, wobei sich an eine Vorbearbeitung eine Feinbearbeitung anschließen soll. Bevor der zweite Schritt zur Herstellung einer unrunden Ausgangsform angegangen wird, also bevor mit der Feinbearbeitung begonnen wird, sieht die DE 10 2007 023 297 A1 vor eine Gleitschicht auf die vorbearbeitete Ausgangsform aufzubringen. Dies kann gemäß der DE 10 2007 023 297 A1 nur mit einem thermischen Spritzverfahren erfolgen, wobei an ein Lichtbogendrahtspritzen, an ein atmosphärisches Plasmaspritzen oder an ein Hochgeschwindigkeitsflammspritzen gedacht ist. Auch Plasmapulverspritzen kann ein geeignetes Spritzverfahren sein. Dabei weist die DE 10 2007 023 297 A1 insbesondere darauf hin, dass die Schichtdicke der aufgetragenen Schicht nicht kleiner als mindestens 50µm sein soll. Zudem sollte die Oberfläche vor dem Beschichten thermisch, mechanisch, chemisch oder wasserstrahlunterstützt vorbehandelt werden.The DE 10 2007 023 297 A1 discloses that a two-stage method is to be provided, with a finishing being to follow a pre-processing. Before the second step towards the production of a non-circular starting form is started, i.e. before the fine machining is started, she sees DE 10 2007 023 297 A1 before applying a sliding layer on the pre-processed initial shape. This can be done according to the DE 10 2007 023 297 A1 only with a thermal spraying process, whereby one considers arc wire spraying, atmospheric plasma spraying or high-speed flame spraying. Plasma powder spraying can also be a suitable spraying method. The DE 10 2007 023 297 A1 in particular that the layer thickness of the applied layer should not be less than at least 50 µm. In addition, the surface should be pretreated thermally, mechanically, chemically or with a water jet before coating.

Bei diesen thermischen Beschichtungsverfahren treffen aufgeschmolzene Beschichtungspartikel mit hoher Temperatur und zuweilen sehr hoher Geschwindigkeit auf die zu beschichtende Oberfläche, um die thermische Spritzschicht zu erzeugen. Ersichtlich ist dabei der Nachteil, dass der zu beschichtende Grundwerkstoff quasi einer ungesteuerten Wärmebehandlung unterzogen wird, so dass sich dessen Materialeigenschaften verändern können. Zudem wird sich der Zylinderblock, in welchem die zu beschichtende Zylinderbohrung angeordnet ist, sehr stark erwärmen, so dass sich die Weiterverarbeitung des Zylinderblockes für die Dauer der notwendigen Abkühlphase verzögert.In these thermal coating processes, melted coating particles hit the surface to be coated at high temperature and sometimes at very high speed in order to produce the thermal spray coating. The disadvantage is that the base material to be coated is subjected to an uncontrolled heat treatment, so that its material properties can change. In addition, the cylinder block in which the cylinder bore to be coated is arranged will heat up considerably, so that the further processing of the cylinder block is delayed for the duration of the necessary cooling phase.

Mittels thermischer Spritzverfahren können tribologisch geeignete VerschleißSchutzschichten hergestellt werden. Solche Beschichtungen werden jedoch bei Motorblöcken aus Grauguss-Material (GG-Material) in der Praxis nicht benutzt, weil die gehonte GG-Oberfläche selber bereits tribologisch gut geeignet ist aufgrund der vorliegenden Graphit-Lamellen mit deren selbstschmierenden Wirkung. Daher werden in GG-Motorblöcken insbesondere verschlissene Laufbahnen durch Aufspritzen von Stahlschichten wieder in den Original-Zustand gebracht. Durch Honen lässt sich dann wieder der Originaldurchmesser einstellen. Von solchen thermisch spritz-reparierten Motoren ist bekannt, dass sie einen niedrigeren Ölverbrauch bzw. höhere Leistung zeigen als Motoren, die durch Ausspindeln der Bohrung und Verwendung von Übermaß-Kolben instandgesetzt wurden. Dabei stellt sich eine weiter reduzierte Reibung zwischen Kolbenring und der porösen thermischen Spritzschicht ein, wobei die Poren quasi als Ölreservoir fungieren und besonders im Bereich der Kolbenumkehrpunkte und somit im Bereich der Mischreibung zusätzliches Öl für den Kolbenring bereitstellen.Thermal spray processes can be used to produce tribologically suitable wear protective layers. However, such coatings are not used in practice for engine blocks made of gray cast iron material (GG material) because the honed GG surface itself is already well suited tribologically due to the graphite lamellae with their self-lubricating effect. Therefore, in GG engine blocks, worn raceways in particular are restored to their original condition by spraying on steel layers. The original diameter can then be set again by honing. Such thermally spray-repaired engines are known to have a lower oil consumption or higher output than engines that have been repaired by spinning out the bore and using oversized pistons. This results in a further reduced friction between the piston ring and the porous thermal spray layer, the pores acting as an oil reservoir and providing additional oil for the piston ring, particularly in the area of the piston reversal points and thus in the area of the mixed friction.

Bei Aluminium-Motorblöcken (Al-Motorblöcken) dagegen ist die Oberfläche vor dem Beschichten zu aktivieren und aufzurauen, was z.B. mittels Wasserstrahlen oder durch mechanisches Aufrauen geschehen kann. Beide Verfahren kommen jedoch für GG-Motorblöcke nicht in Betracht, so dass ein Ausspindeln mit höherer Rauigkeit, verbunden mit Flex-Honen oder Hammerschlagbürsten notwendig ist. Zusätzlich muss eine dünne Lage an kostenintensivem NiAl-Haftgrundmaterial thermisch aufgespritzt werden bevor die eigentliche Funktionsbeschichtung thermisch aufgetragen wird. Durch diesen 2-stufigen Prozess sind die Beschichtungskosten bei GG-Motorblöcken hoch, wodurch das thermische Spritzen hierbei benachteiligt ist. Demgegenüber fällt die Kostenrechnung bei Motorblöcken aus Al-Material günstiger aus: hier kann der Liner aus GG-Material wegfallen. Durch einfaches mechanisches Aufrauen des weichen Al-Materials wird ein Aufrauprofil mit einem Hinterschnitt erzeugt, so dass die Beschichtung direkt auf diese aufgeraute Oberfläche thermisch aufgespritzt werden kann. Durch den Hinterschnitt ergibt sich auch ohne jeden Haftgrund eine sehr hohe Haftfestigkeit.In the case of aluminum engine blocks (Al engine blocks), on the other hand, the surface must be activated and roughened before coating, which can be done, for example, by means of water jets or by mechanical roughening. However, both methods are not suitable for GG engine blocks, so that it is necessary to uncoil with higher roughness, combined with flex honing or hammer blows. In addition, a thin layer of cost-intensive NiAl adhesive base material must be thermally sprayed on before the actual functional coating is applied thermally. This 2-stage process means that the coating costs are reduced GG engine blocks high, which puts thermal spraying at a disadvantage. In contrast, the cost calculation for engine blocks made of aluminum material is cheaper: here the liner made of GG material can be omitted. Simply roughening the soft Al material mechanically creates a roughened profile with an undercut so that the coating can be thermally sprayed directly onto this roughened surface. The undercut results in a very high adhesive strength even without any adhesive base.

Die thermischen Spritzschichten zeigen jedoch eine Schwachstelle beispielsweise hinsichtlich der Unterkorrosionsproblematik auf, z.B. wenn aggressive, verunreinigte Kraftstoffe verwendet werden. In dem Fall ist es notwendig, hoch Cr-legierte Pulver oder Drähte als Zusatzwerkstoff zum thermischen Spritzbeschichten zu verwenden, wodurch die Herstellkosten weiter steigen. Aufgrund der durchgehenden Porosität kann es dann aber trotzdem passieren, dass Kondensate oder Säuren durch die Schicht hindurch das Grundmaterial angreifen können. Nur durch zusätzliche Imprägnierung der Schichten lassen sich solche Unterkorrosionsprobleme verhindern.The thermal spray coatings, however, show a weak point, for example with regard to the problem of sub-corrosion, e.g. if aggressive, contaminated fuels are used. In this case, it is necessary to use highly Cr-alloyed powders or wires as a filler material for thermal spray coating, which further increases the manufacturing costs. However, due to the continuous porosity, condensates or acids can still attack the base material through the layer. Such under-corrosion problems can only be prevented by additional impregnation of the layers.

Weiter können mittels Plasma-Pulverspritzverfahren von Zr-O2 mit Yttrium-Oxid-Stabilisierung Wärmedämmschichten für Verbrennungsmotoren oder Gasturbinen hergestellt werden. Solche Plasma-Pulverspritzschichten zeichnen sich durch niedrige Wärmeleitung auch bei sehr hohen Temperaturen bis über 1100°C aus. Auf der anderen Seite können solche Plasma-Pulverspritzschichten aufgrund ihres mikrorissigen Schichtaufbaus mechanisch nicht belastet werden, wobei solche Wärmedämmschichten als tribologisch beanspruchte Beschichtung in der Zylinderlaufbahn nicht geeignet wären.Furthermore, thermal powder coatings for Zr-O2 with yttrium oxide stabilization can be used to produce thermal insulation layers for internal combustion engines or gas turbines. Such plasma powder spray coatings are characterized by low heat conduction even at very high temperatures up to over 1100 ° C. On the other hand, due to their micro-cracked layer structure, such plasma powder spray layers cannot be mechanically loaded, such thermal insulation layers would not be suitable as a tribologically stressed coating in the cylinder race.

Angesichts dieser Beobachtungen bieten Verfahren zum Herstellen beschichteter Bohrungsflächen, insbesondere Verfahren zur Beschichtung der Bohrung eines Zylinderblocks eines Verbrennungsmotors weiterhin Raum für Verbesserungen.In light of these observations, methods of making coated bore surfaces, particularly methods of coating the bore of a cylinder block of an internal combustion engine, continue to offer room for improvement.

Vor diesem Hintergrund liegt der Erfindung die Aufgabe zugrunde, ein Verfahren der Eingangs genannten Art vorteilhaft weiterzubilden.Against this background, the invention is based on the object of advantageously developing a method of the type mentioned at the outset.

Die Lösung dieser Aufgabe gelingt mit einem Verfahren mit den Merkmalen des Anspruchs 1 und einem Zylinderblock mit den Merkmalen des Anspruchs 9.This object is achieved with a method with the features of claim 1 and a cylinder block with the features of claim 9.

Es ist darauf hinzuweisen, dass die in der nachfolgenden Beschreibung einzeln aufgeführten Merkmale sowie Maßnahmen in beliebiger, technisch sinnvoller Weise miteinander kombiniert werden können und weitere Ausgestaltungen der Erfindung aufzeigen. Die Beschreibung charakterisiert und spezifiziert die Erfindung und deren Teile insbesondere im Zusammenhang mit den Figuren zusätzlich.It should be pointed out that the features and measures listed individually in the description below can be combined with one another in any technically meaningful manner and show further refinements of the invention. The description additionally characterizes and specifies the invention and its parts, in particular in connection with the figures.

Gemäß der Erfindung wird nachfolgend ein Verfahren zum Herstellen einer beschichteten, inneren Oberfläche einer beschichteten Bohrung eines Verbrennungsmotors vorgestellt, umfassend zumindest die Schritte:

  • Herstellen eines im Rohling vorliegenden Basiskörpers;
  • Aufbohren der Bohrung und Vorbearbeiten derselben;
  • Aufbringen einer Email-Beschichtung auf die innere Oberfläche der Bohrung,
  • Wärmenachbehandlung der beschichteten Bohrung, wobei die Email-Beschichtung zusammen mit dem Basiskörper aus GG-Substratmaterial im Durchlaufofen bei einer Temperatur zwischen 750° C und 900°C, bevorzugt bei T = 840°C, 5 bis 30 Minuten geglüht wird, oder die Email-Beschichtung zusammen mit einem Basiskörper aus einer Aluminiumlegierung bei einer Temperatur zwischen 480°C und 560°C, bevorzugt bei T=540°C, im Durchlaufofen 5 bis 30 Minuten geglüht wird so dass sich die Email-Beschichtung jeweils mit dem Grundwerkstoff der Bohrung metallurgisch durch Phasenbildung verbinden kann; und
  • Fertigbearbeiten der Email-Beschichtung derart, dass in der Email-Beschichtung vorhandene Poren angeschnitten oder offengelegt werden.
According to the invention, a method for producing a coated, inner surface of a coated bore of an internal combustion engine is presented below, comprising at least the steps:
  • Producing a base body present in the blank;
  • Drilling and pre-machining the hole;
  • Applying an enamel coating to the inner surface of the hole,
  • Post-heat treatment of the coated bore, the enamel coating together with the base body made of GG substrate material being annealed in a continuous furnace at a temperature between 750 ° C. and 900 ° C., preferably at T = 840 ° C., for 5 to 30 minutes, or the enamel -Coating together with a base body made of an aluminum alloy at a temperature between 480 ° C and 560 ° C, preferably at T = 540 ° C, is annealed in a continuous furnace for 5 to 30 minutes so that the enamel coating in each case with the base material of the bore can connect metallurgically by phase formation; and
  • Finishing the enamel coating in such a way that pores present in the enamel coating are cut or exposed.

Die auf die innere Oberfläche der Bohrung aufgebrachte Email-Beschichtung weist eine besonders gute Wärmedämmeigenschaft und besonders gute tribologische Eigenschaften auf. Zudem wird eine Unterkorrosion sicher vermieden, wobei auf kostenintensive Zusatzstoffe wie z.B. Zirkon-Oxid/Yttrium-Oxid verzichtet werden kann. Insofern wird zielführend ein Verfahren bereitgestellt, bei dem eine geeignete Beschichtung alle Anforderungen an eine sichere Funktion des Bauteils bei minimalen Herstellkosten erfüllt, wobei das erfindungsgemäße Verfahren gleichzeitig aber auch in die bestehende Fertigungskette zum Herstellen der Motorblöcke ohne große Umstände integrierbar ist.The enamel coating applied to the inner surface of the bore has particularly good thermal insulation properties and particularly good tribological properties. Undercorrosion is also reliably avoided, and costly additives such as zirconium oxide / yttrium oxide can be dispensed with. In this respect, a method is purposefully provided in which a suitable coating fulfills all requirements for a reliable function of the component with minimal manufacturing costs, the method according to the invention simultaneously but can also be integrated into the existing production chain for the manufacture of the engine blocks without great difficulty.

Bei der erfindungsgemäßen Email-Beschichtung handelt es sich bevorzugt um ein Schmelzgemisch. Bei der Emailtemperatur schmelzen die glasbildenden Oxide zu einer Glasschmelze zusammen. Glasbildende Oxide können dabei SiO2, B2O3, Na2O, K2O und Al2O3 sein. Grundemails weisen ca. 23 - 34 Gew% (Gewichtsprozente) Borax, 28 - 52 Gew% Feldspat, 5 - 20 Gew% Quarz, ca. 5 Gew% Fluorid, sowie als Rest Soda und Natriumnitrat auf. Als Trübungsmittel können die Oxide von Ti, Zr und Mo dienen.The enamel coating according to the invention is preferably a melt mixture. At the enamel temperature, the glass-forming oxides melt together to form a glass melt. Glass-forming oxides can be SiO 2 , B 2 O 3 , Na 2 O, K 2 O and Al 2 O 3 . Basic emails contain approx. 23 - 34% by weight (weight percent) borax, 28 - 52% by weight feldspar, 5 - 20% by weight quartz, approx. 5% by weight fluoride, as well as the rest of soda and sodium nitrate. The oxides of Ti, Zr and Mo can serve as opacifiers.

Um zu erreichen, dass die Email-Beschichtung fest auf dem metallischem Untergrund, also auf dem Grundwerkstoff haftet, sind beispielsweise Bestandteile von Kobalt-, Mangan- oder Nickel-Oxiden vorgesehen. Möglich ist noch, keramische Pigmente, wie z.B. Eisenoxide, Chromoxide und Spinelle einzusetzen.In order to ensure that the enamel coating adheres firmly to the metallic substrate, that is to say to the base material, components of cobalt, manganese or nickel oxides are provided, for example. It is still possible to use ceramic pigments, e.g. Use iron oxides, chromium oxides and spinels.

Die genannten Stoffe werden in bevorzugter Ausgestaltung fein gemahlen und geschmolzen. Die Schmelze wird abgeschreckt, also bevorzugt in Wasser gegeben, wobei die so entstehende körnige glasartige Fritte im sich anschließenden Schritt wieder fein gemahlen wird. Beim dem Mahlvorgang werden beispielsweise 30 % bis 40 % Wasser zusammen mit Ton und Quarzmehl zugesetzt. Je nach Art des Emails kommen noch die erwähnten Trübungsstoffe und Farboxide hinzu.In a preferred embodiment, the substances mentioned are finely ground and melted. The melt is quenched, that is to say preferably placed in water, the granular glassy frit thus formed being finely ground again in the subsequent step. In the grinding process, for example, 30% to 40% water is added together with clay and quartz powder. Depending on the type of enamel, the opacifiers and color oxides mentioned are added.

So wird ein Emailschlicker gebildet, welcher zur besseren Mischung einige Zeit, bevorzugt einige Tage ruhen sollte, bevor der Emailschlicker weiterverwendet würde. Durch Verwendung geeigneter Stellmittel wird sichergestellt, dass sich eine gleichmäßige Schichtdicke z.B. nach einer Tauchbeschichtung ergibt, wobei auf eine mögliche Tauchbeschichtung mit einer Flutvorrichtung noch näher eingegangen wird.In this way, an enamel slip is formed, which should rest for a better time, preferably a few days, for better mixing before the enamel slip would be used again. The use of suitable adjusting means ensures that a uniform layer thickness, e.g. after a dip coating, whereby a possible dip coating with a flood device is discussed in more detail.

Zum Aufbringen der Email-Beschichtung, also des Emailschlickers können unterschiedliche Vorgehen gewählt werden. Zum Einen kann der wässrige Emailschlicker mittels einer rotierenden Vorrichtung, welche zugleich zur Rotation um ihre Hochachse in Hochrichtung der Bohrung in derselben hin- und herbewegbar ist aufgebracht werden. Die Vorrichtung kann als Lanze ausgeführt sein, wobei das Material in mehreren Übergängen, also Schichten aufbringbar ist. Die Lanze weist günstiger Weise an ihrem Auftragende zumindest eine Austrittsöffnung auf, aus welcher der Emailschlicker austreten kann. Durch die Rotation wird der Emailschlicker quasi auf die zu beschichtende Oberfläche geschleudert. Natürlich können auch mehrere Austrittsöffnungen vorgesehen sein, die sowohl in Umfangsrichtung gesehen als auch in Hochrichtung der Lanze an dieser angeordnet sein können. In möglicher Ausgestaltung kann vorgesehen sein, zunächst eine bestimmte Materialstärke aufzutragen, welche sodann getrocknet wird, bevor die nächste Schicht, also weiteres Material aufgebracht wird. Das Trocknen dieser Schicht kann z.B. mit einer Induktionsspule erfolgen. Natürlich kann auch vorgesehen sein, die Email-Beschichtung in einem einzigen Schritt aufzubringen.Different procedures can be used to apply the enamel coating, i.e. the enamel slip. On the one hand, the aqueous enamel slip can be applied by means of a rotating device, which can be moved back and forth in the vertical direction of the bore for rotation about its vertical axis. The device can be designed as a lance, the material being able to be applied in several transitions, that is to say layers. The lance points at least one outlet opening from which the enamel slip can emerge at its end of the order. As a result of the rotation, the enamel slip is thrown onto the surface to be coated. Of course, several outlet openings can also be provided, which can be arranged on the lance as seen in the circumferential direction as well as in the vertical direction thereof. In a possible embodiment it can be provided that a certain thickness of material is first applied, which is then dried before the next layer, that is to say further material, is applied. This layer can be dried with an induction coil, for example. Of course, it can also be provided that the enamel coating is applied in a single step.

Wie bereits erwähnt kann die Email-Beschichtung zum Anderen aber auch in einem Tauchvorgang aufgebracht werden. Dazu kann der gesamte Zylinderblock, in dem sich eine oder mehrere zu beschichtende Bohrungen befinden in bevorzugter Ausgestaltung mit seiner Kopfseite zuerst in das Emailschlickerbad eingebracht werden. Dabei wird zwangsläufig auch das Äußere des Zylinderblocks beschichtet, was hinsichtlich der Materialeinsparung nachteilig ist. Zielführend ist jedoch, wenn die Bohrung mit dem Emailschlicker geflutet wird, was im Sinne der Erfindung ebenfalls als Tauchvorgang mit Flutvorrichtung bezeichnet wird. Dabei wird der gesamte Zylinderblock mit seiner Kopfseite zuerst auf eine Flutvorrichtung gestellt. Die Flutvorrichtung weist günstiger Weise zumindest eine Kammer, die zumindest eine Austrittsöffnung aufweist, wobei noch eine Zuführöffnung vorgesehen ist. An die Zuführöffnung ist eine Leitung angeschlossen, welche den Emailschlicker zur Flutvorrichtung führt, so dass in dieser, also in der Kammer ein solcher Druck entsteht, dass der Emailschlicker aus der Austrittsöffnung von unten in die zu beschichtende Bohrung eintritt. Günstiger Weise sind noch Dichtelemente, z.B. in der Ausgestaltung als Dichtlippe an der Flutvorrichtung vorgesehen, an welcher sich die Wand der zu beschichtenden Bohrung in Umfangsrichtung anlegen kann, so dass die Bohrung über ihre Wand zur Flutvorrichtung abgedichtet ist. Die gesamte Bohrung, also die innere Oberfläche derselben wird so mit dem Emailschlicker beschichtet. Dabei kann ein mehrstufiger Schichtaufbau mit der optionalen oben genannten Zwischentrocknung einzelner Teilschichten genauso vorgesehen wie das Auftragen der Email-Beschichtung in einem Schritt. Der Bohrung wird so von unten nach oben geflutet. Möglich ist natürlich die Bohrung von oben nach unten mit dem Emailschlicker zu fluten. Dazu wird der Emailschlicker in die nach oben geöffnete Bohrung eingebracht, was ebenfalls als Tauchvorgang im Sinne der Erfindung angesehen wird.As already mentioned, the enamel coating can also be applied in one dipping process. For this purpose, the entire cylinder block, in which one or more bores to be coated are located, in a preferred embodiment with its head side first being introduced into the enamel slip bath. The exterior of the cylinder block is inevitably coated, which is disadvantageous in terms of material savings. However, it is expedient if the bore is flooded with the enamel slip, which is also referred to in the sense of the invention as a diving process with a flooding device. The entire cylinder block is first placed on a flood device with its head side. The flooding device advantageously has at least one chamber which has at least one outlet opening, a feed opening also being provided. A line is connected to the feed opening, which leads the enamel slurry to the flooding device, so that a pressure is created in it, that is to say in the chamber, that the enamel slip enters the bore to be coated from the outlet opening from below. Conveniently, sealing elements are also provided, for example in the configuration as a sealing lip on the flooding device, on which the wall of the bore to be coated can rest in the circumferential direction, so that the bore is sealed off from its wall to the flooding device. The entire bore, i.e. the inner surface of the same, is coated with the enamel slip. A multi-stage layer structure with the optional intermediate drying of individual partial layers as well as the application of the enamel coating in one step can be provided. The borehole is flooded from bottom to top. Of course it is possible to flood the hole from top to bottom with the enamel slip. To do this, the email slip is opened in the top Drilled hole, which is also considered a diving process in the sense of the invention.

Zielführend ist, wenn die gesamte Bohrung sowohl vollumfänglich als auch über die gesamte Hocherstreckung mit der Email-Beschichtung versehen wird.It is expedient if the entire bore is provided with the enamel coating both in full and over the entire extension.

Zweckmäßig ist weiter, wenn der Basiskörper, also der Zylinderblock aus einem Grauguss hergestellt ist, wobei als Herstellungsverfahren das Sandgussverfahren geeignet ist. Dieses ist allgemein bekannt, so dass darauf nicht weiter eingegangen wird. Die Bohrung, also die Zylinderbohrung wird anschließend aufgebohrt und vorbearbeitet, wobei die Bohrung durch Ausspindeln auf ein Übermaß von 1 bis 2 mm im Durchmesser aufgebohrt wird. Zielführend im Sinne der Erfindung ist, wenn die Oberfläche im Bereich der Bohrung, also die innere Bohrungsoberfläche auf eine Rauigkeit von Ra 6 bis 7 µm gespindelt wird.It is also expedient if the base body, that is to say the cylinder block, is produced from a gray cast iron, the sand casting process being suitable as the production method. This is generally known, so it will not be discussed further. The bore, that is to say the cylinder bore, is then drilled out and pre-machined, the bore being drilled out to an oversize of 1 to 2 mm in diameter. It is expedient in the sense of the invention if the surface in the area of the bore, ie the inner surface of the bore, is spindled to a roughness of Ra 6 to 7 µm.

Nach dieser Vorbearbeitung wird die Email-Beschichtung aufgebracht. Die Email-Beschichtung wird als wässrige Suspension aufgetragen und anschließend in einem Durchlaufofen z.B. bei T = 90°C für ca. 10 Minuten getrocknet. Möglich ist auch eine Trocknung durch Heizstrahler, oder ein Aufwärmen mittels der zuvor genannten Induktionsspule. Anschließend werden die Bauteile bei T = 840°C, 10 Minuten im Durchlaufofen geglüht, so dass sich die Email-Beschichtung mit dem GG-Substratmaterial des Zylinderblocks metallurgisch durch Phasenbildung verbinden kann. Bei diesem Einbrenn-Vorgang kommt es zu einer Bildung einer dichten, geschlossenen Oxid-Beschichtung, die gegenüber dem Korrosionsangriff durch Kondensate oder aggressive alternative Kraftstoffe sehr widerstandsfähig ist. Die erfindungsgemäßen Email-Beschichtungen zeichnen sich gegenüber den Galvanik- oder thermischen Spritzbeschichtungen dadurch aus, dass sie nicht unterwandert werden können. Wenn thermisch aufgebrachte Spritz-Schichten unterwandert werden, kann sich eine Fe-Oxid-Phase unter der Beschichtung ausbilden, was zu einer starken Volumenvergrößerung, verbunden mit dem Abplatzen der thermischen Spritzbeschichtung, führt. Die erfindungsgemäße Email-Beschichtung dagegen kann nicht weiter geschädigt werden, wenn durch lokalen Schaden die Schicht bis zum Grundwerkstoff abgetragen ist. Es wird dann nur im Bereich der fehlenden EmailSchicht ein Rostschaden auftreten, welcher sich aber nicht weiter vergrößert. Neben dieser guten Korrosionsbeständigkeit zeichnet sich die erfindungsgemäße Email-Beschichtung durch gute Verschleißbeständigkeit aufgrund der hohen Schichthärte von typisch 600 - 800HV0,1 aus. Dies bedeutet eine dreifach höhere Härte als bei dem GG-Basismaterial.After this preprocessing, the enamel coating is applied. The enamel coating is applied as an aqueous suspension and then dried in a continuous oven, eg at T = 90 ° C for approx. 10 minutes. Drying by radiant heaters or heating using the induction coil mentioned above is also possible. The components are then annealed at T = 840 ° C for 10 minutes in a continuous furnace, so that the enamel coating can be metallurgically bonded to the GG substrate material of the cylinder block by phase formation. This burn-in process leads to the formation of a dense, closed oxide coating that is very resistant to corrosion attack by condensates or aggressive alternative fuels. The enamel coatings according to the invention are distinguished from the electroplating or thermal spray coatings by the fact that they cannot be infiltrated. If thermally applied spray layers are infiltrated, an Fe oxide phase can form under the coating, which leads to a large increase in volume, combined with the flaking off of the thermal spray coating. The enamel coating according to the invention, on the other hand, cannot be further damaged if the layer is removed down to the base material due to local damage. Rust damage will only occur in the area of the missing enamel layer, but this will not increase further. In addition to this good corrosion resistance, the enamel coating according to the invention is characterized by good wear resistance due to the high layer hardness of typically 600-800HV0.1. This means that the hardness is three times higher than that of the GG base material.

In weiterem Vorgehen zum Herstellen der Email-Beschichtung ist zweckmäßiger Weise vorgesehen, eine weitere Wärmebehandlung durchzuführen. Dazu wird der Zylinderblock mit der getrockneten Email-Beschichtung in einem Schutzgas-Ofen auf 800 - 900°C aufgeheizt und ca. 10 - 20 Minuten gehalten. Anschließend erfolgt eine schnelle Abkühlung bevorzugt in einer Salzschmelze, so dass sich eine deutliche höhere Festigkeit des Zylinderblockes ergibt als beim konventionellen GG-Material. Überraschender Weise laufen die Email-Einbrennbehandlung und diese Wärmebehandlung im gleichen Temperatur-Zeit-Fenster ab, was mit der Erfindung genutzt wird. Insofern werden die Email-Einbrennbehandlung und diese Wärmebehandlung miteinander verbunden, so dass sich durch diese Einbrenn- und Abschreckoperation also ein Zylinderblock mit erhöhter mechanischer Festigkeit sowie einer Zylinderbohrung mit guter Wärmedämmung und guter Verschleiß- und Korrosionsbeständigkeit ergibt. Die Wärmebehandlung ist zielführend als bainitische Grauguss Wärmebehandlung durchzuführen (AGI-Wärmebehandlung = Austempered Gray Iron Wärmebehandlung).In a further procedure for producing the enamel coating, it is expedient to carry out a further heat treatment. To do this, the cylinder block with the dried enamel coating is heated to 800 - 900 ° C in a protective gas oven and held for approx. 10 - 20 minutes. This is followed by rapid cooling, preferably in a molten salt, so that the cylinder block has a significantly higher strength than with conventional GG material. Surprisingly, the enamel baking treatment and this heat treatment run in the same temperature-time window, which is used with the invention. In this respect, the enamel baking treatment and this heat treatment are combined, so that this baking and quenching operation results in a cylinder block with increased mechanical strength and a cylinder bore with good thermal insulation and good wear and corrosion resistance. The heat treatment is effective as a bainitic cast iron heat treatment (AGI heat treatment = Austempered Gray Iron heat treatment).

Nach dem Einbrennen der Email-Beschichtung werden die Motorblöcke fertig bearbeitet und in der Laufbahn auf Endmaß gehont.After the enamel coating has been burned in, the engine blocks are finished and honed to their final dimensions in the race track.

Bevorzugt werden Schichtdicken von 500-1000µm aufgebracht. Je dicker die Email-Beschichtung ist, umso höher ist deren Wärmedämmwirkung. Diese Wärmedämmung ergibt sich durch die Verwendung von Oxiden wie Si, Ti, Ca-Oxiden aber auch durch die typischen Luftblaseneinschlüssen in der erstarrten Glasmatrix. Diese harte und spröde Schicht lässt sich durch Diamant-Honleisten sehr einfach bearbeiten, wobei diese Luftblasen angeschnitten und offengelegt werden. Besonders hervorzuheben ist die Tatsache, dass es sich dabei nicht um miteinander verbundene Poren oder Porennester handelt wie bei einer thermisch aufgebrachten Spritzbeschichtung, so dass sich in den Poren der erfindungsgemäßen Email-Beschichtung ein hoher hydrodynamischer Druck aufbauen kann und der Ölfilm durch den Kolbenring nicht in verbundene Poren weggedrückt werden kann.Layer thicknesses of 500-1000 μm are preferably applied. The thicker the enamel coating, the higher its thermal insulation effect. This thermal insulation results from the use of oxides such as Si, Ti, Ca oxides but also from the typical air bubble inclusions in the solidified glass matrix. This hard and brittle layer is very easy to work with diamond honing stones, whereby these air bubbles are cut and exposed. Of particular note is the fact that these are not interconnected pores or pore nests as in the case of a thermally applied spray coating, so that a high hydrodynamic pressure can build up in the pores of the enamel coating according to the invention and the oil film through the piston ring does not connected pores can be pushed away.

Das erfindungsgemäße Verfahren eignet sich aufgrund der hervorragenden Korrosions- und Verschleißbeständigkeit, guten Wärmedämmung sowie des guten Reibverhaltens für die Beschichtung von Zylinderlaufbahnen von Verbrennungsmotoren. Darüber hinaus kann der Einbrennzyklus der Email-Beschichtung verbunden werden mit der AGI Wärmebehandlung, so dass der Zylinderblock anschließend eine höhere Festigkeit aufweist. Die Zusammensetzung der Email-Beschichtung kann durch Zugabe von harten Karbiden so angepasst werden, dass die Verschleißbeständigkeit z.B. für den Einsatz in hochaufgeladenen Motoren angehoben werden kann. Im Vergleich zu Zr-Oxid- Pulver (derzeit 60€/kg und Verwendung des teuren Pulver-Plasma-Spritzverfahrens) ist das Nass-Schlickern von Emails (derzeit 2-4€/kg) sehr kostengünstig.Because of the excellent resistance to corrosion and wear, good thermal insulation and good friction behavior, the method according to the invention is suitable for coating cylinder liners of internal combustion engines. In addition, the baking cycle of the enamel coating can be combined with the AGI heat treatment, so that the cylinder block subsequently has a higher strength. The composition of the enamel coating can be adjusted by adding hard carbides so that the wear resistance e.g. can be raised for use in highly charged engines. Compared to Zr oxide powder (currently € 60 / kg and using the expensive powder plasma spray process), wet slurrying of enamels (currently € 2-4 / kg) is very cost-effective.

Mit der Erfindung wird also ein Verfahren zur Herstellung einer Verschleiss- und Korrosionsbeschichtung innerhalb der Bohrung eines Zylinderblocks eines Verbrennungsmotors aus Grauguss-Material zur Verfügung gestellt. Diese Beschichtung erfüllt erfindungsgemäß zumindest die folgenden Anforderungen: sie reduziert infolge der niedrigen Wärmeleitfähigkeit den Wärmeverlust im Verbrennungsprozess und erlaubt dadurch die Wärme im Verbrennungsprozess thermodynamisch besser auszunutzen zur Erzielung eines höheren Wirkungsgrades. Zusätzlich weist diese Beschichtung aber auch gute tribologische Eigenschaften auf, um den Reib-Verschleiß-Bedingungen der Kolbengruppe gewachsen zu sein. Diese Anforderungen werden erfindungsmäßig gelöst durch das Einbrennen der gegebenenfalls harten Email-Beschichtung. Weiterhin wird erfindungsgemäß die notwendige Einbrennbehandlung der Email-Beschichtung verbunden mit der AGI Wärmebehandlung, so dass für diese Emaillierung nur sehr geringe Kosten anfallen und gleichzeitig der Zylinderblock eine höhere Festigkeit erhält als ein Zylinderblock aus konventionellem GG-Material. Denkbar ist auch, einen Zylinderblock aus Aluminium, also dessen Zylinderlaufbahn mit der Email-Beschichtung zu versehen.The invention thus provides a method for producing a wear and corrosion coating within the bore of a cylinder block of an internal combustion engine made of gray cast iron material. According to the invention, this coating at least meets the following requirements: due to the low thermal conductivity, it reduces the heat loss in the combustion process and thus allows the heat in the combustion process to be better used thermodynamically in order to achieve a higher degree of efficiency. In addition, this coating also has good tribological properties in order to cope with the friction-wear conditions of the piston group. According to the invention, these requirements are met by burning in the hard enamel coating, if necessary. Furthermore, according to the invention, the necessary baking treatment of the enamel coating is combined with the AGI heat treatment, so that only very low costs are incurred for this enamelling and at the same time the cylinder block is given a higher strength than a cylinder block made of conventional GG material. It is also conceivable to provide an aluminum cylinder block, that is to say its cylinder barrel, with the enamel coating.

Optional kann die Email-Beschichtungsoberfläche nach dem Schritt des Einbrennens noch einer Schlussbehandlung, also einem Finish unterzogen werden. Bevorzugt ist vorgesehen, die Reibflächen drehend zu bearbeiten und die Zunderschicht, welche aufgrund des Glühprozesses entstand zu entfernen. Möglich ist auch, eine Nachbearbeitung der Bohrung durch ein Nachschleifen, wobei Diamant- oder Hartstoff-Topfscheiben zum Einsatz kommen können. Denkbar ist eine Nachbearbeitung mittels Ausdrehen oder Ausspindeln, was trotz der hohen Härte aufgrund der Sprödigkeit machbar ist, wobei PKD (polykristalliner Diamant) Wendeschneidplättchen bevorzugt sind.Optionally, the enamel coating surface can be subjected to a final treatment, i.e. a finish, after the baking step. Provision is preferably made to machine the friction surfaces in a rotating manner and to remove the scale layer which has arisen as a result of the annealing process. It is also possible to rework the hole by regrinding, using diamond or Hard material cup wheels can be used. Post-processing by turning or spinning is conceivable, which is feasible despite the high hardness due to the brittleness, with PCD (polycrystalline diamond) indexable inserts being preferred.

Weitere vorteilhafte Einzelheiten und Wirkungen der Erfindung sind im Folgenden anhand von unterschiedlichen, in den Figuren dargestellten Ausführungsbeispielen näher erläutert. Es zeigen:

Fig. 1
ein Vorgehen zum Beschichten einer Bohrung mit einer Email-Beschichtung,
Fig.2
ein weiteres Vorgehen zum Beschichten einer Bohrung mit einer Email-Beschichtung, und
Fig. 3
eine mit der Email-Beschichtung versehene Bohrung im Längsschnitt.
Further advantageous details and effects of the invention are explained in more detail below on the basis of different exemplary embodiments shown in the figures. Show it:
Fig. 1
a procedure for coating a hole with an enamel coating,
Fig. 2
another procedure for coating a bore with an enamel coating, and
Fig. 3
a bore with the enamel coating in longitudinal section.

In den unterschiedlichen Figuren sind gleiche Teile stets mit denselben Bezugszeichen versehen, so dass diese in der Regel auch nur einmal beschrieben werden.In the different figures, the same parts are always provided with the same reference numerals, so that these are usually only described once.

Figur 1 zeigt ein Verfahren zum Beschichten einer Bohrung 1 mit einer Email-Beschichtung 2. Die Bohrung 1 ist in einem Zylinderblock 3 eingebracht, welcher als Prinzipskizze in Figur 2 erkennbar ist. Von dem Zylinderblock 3 ist in Figur 1 lediglich die innere Oberfläche 4 der Bohrung 1 erkennbar. Figure 1 shows a method for coating a bore 1 with an enamel coating 2. The bore 1 is made in a cylinder block 3, which is shown in FIG Figure 2 is recognizable. Of the cylinder block 3 is in Figure 1 only the inner surface 4 of the bore 1 can be seen.

Der Zylinderblock 3 wurde als Basiskörper 3 in einem Sandgussverfahren aus einem Grauguss hergestellt. Die Bohrung 1 wurde durch Ausspindeln auf ein Übermaß von 1 bis 2 mm im Durchmesser aufgebohrt. Die Oberfläche 4 im Bereich der Bohrung 1 wurde zudem auf eine Rauigkeit von Ra 6 bis 7 µm gespindelt.The cylinder block 3 was produced as a base body 3 in a sand casting process from a gray cast iron. The bore 1 was drilled out to an oversize of 1 to 2 mm in diameter. The surface 4 in the area of the bore 1 was also spindled to a roughness of Ra 6 to 7 μm.

Die angegeben Werte sollen natürlich nur beispielhaft genannt sein. Die Bohrung 1 wird erfindungsgemäß mit einer Email-Beschichtung 2 versehen.The specified values should of course only be mentioned as examples. According to the invention, the bore 1 is provided with an enamel coating 2.

Die Email-Beschichtung 2 wird in Form eines wässrigen Emailschlickers bei dem Ausführungsbeispiel nach Figur 1 mittels einer rotierenden Vorrichtung 6, welche zugleich zur Rotation um ihre Achse in Hochrichtung der Bohrung 2 in derselben hin und her bewegbar ist aufgebracht. Die Bewegungspfeile hinsichtlich Rotation und Hin und Her bewegen sind in Figur 1 eingezeichnet. Die Vorrichtung 6 kann als Lanze 6 bezeichnet werden, wobei das Material, also der wässrige Emailschlicker in mehreren Übergängen, also Schichten aufbringbar ist. In möglicher Ausgestaltung kann vorgesehen sein, zunächst eine bestimmte Materialstärke aufzutragen, welche sodann getrocknet wird, bevor die nächste Schicht, also weiteres Material aufgebracht wird. Das Trocknen dieser Schicht kann z.B. mit einer Induktionsspule erfolgen. Natürlich kann auch vorgesehen sein, die Email-Beschichtung in einem einzigen Schritt aufzubringen.The enamel coating 2 is in the form of an aqueous enamel slip in the exemplary embodiment Figure 1 by means of a rotating device 6 which at the same time for rotation about its axis in the vertical direction of the bore 2 in the same back and forth is applied. The movement arrows regarding rotation and back and forth are in Figure 1 drawn. The device 6 can be referred to as a lance 6, the material, that is to say the aqueous enamel slip, being able to be applied in several transitions, that is to say layers. In a possible embodiment it can be provided that a certain thickness of material is first applied, which is then dried before the next layer, that is to say further material, is applied. This layer can be dried with an induction coil, for example. Of course, it can also be provided that the enamel coating is applied in a single step.

Wie der Figur 2 entnehmbar ist, kann die Email-Beschichtung 2 zum anderen aber auch in einem Tauchvorgang aufgebracht werden. Erkennbar in Figur 2 ist, dass die Bohrung 1 mit dem Emailschlicker von unten geflutet wird, was im Sinne der Erfindung als Tauchvorgang bezeichnet wird. Dabei wird der gesamte Zylinderblock 3 mit seiner Kopfseite 7 aufstehend auf eine Flutvorrichtung 8 gestellt.Again Figure 2 can be removed, the enamel coating 2 can also be applied in a dipping process. Recognizable in Figure 2 is that the bore 1 is flooded with the enamel slurry from below, which is referred to as a dipping process in the sense of the invention. The entire cylinder block 3 is placed with its head side 7 standing on a flooding device 8.

Die Flutvorrichtung 8 weist günstiger Weise zumindest eine Kammer 9 auf, die eine Austrittsöffnung 10 hat, wobei eine Zuführöffnung 11 vorgesehen ist. An die Zuführöffnung 11 ist eine Leitung 12 angeschlossen, welche den Emailschlicker zur Flutvorrichtung 8 führt, so dass in dieser, also in der Kammer 9 ein solcher Druck entsteht, dass der Emailschlicker aus der Austrittsöffnung 10 von unten in die zu beschichtende Bohrung 1 eintritt. Günstiger Weise sind noch Dichtelemente 13, z.B. in der Ausgestaltung als Dichtlippe 13 an der Flutvorrichtung 8 vorgesehen, an welcher sich die Wand 14, also an deren Stirnseite der zu beschichtenden Bohrung 1 in Umfangsrichtung anlegen kann, so dass die Bohrung 1 über ihre Wand 14 zur Flutvorrichtung 8 abgedichtet ist. Die gesamte Bohrung 1, also die innere Oberfläche 4 derselben wird so mit dem Emailschlicker beschichtet. Dabei kann ein mehrstufiger Schichtaufbau mit der optionalen oben genannten Zwischentrocknung einzelner Teilschichten genauso vorgesehen wie das Auftragen der Email-Beschichtung in einem Schritt.The flooding device 8 advantageously has at least one chamber 9 which has an outlet opening 10, a feed opening 11 being provided. A line 12 is connected to the feed opening 11, which leads the enamel slurry to the flooding device 8, so that pressure, such as this, arises in the chamber 9 that the enamel slip enters the bore 1 to be coated from the outlet opening 10 from below. Sealing elements 13, e.g. provided in the embodiment as a sealing lip 13 on the flood device 8, on which the wall 14, that is to say on the end face of the bore 1 to be coated, can bear in the circumferential direction, so that the bore 1 is sealed via its wall 14 to the flood device 8. The entire bore 1, that is to say the inner surface 4 thereof, is thus coated with the enamel slip. A multi-stage layer structure with the optional intermediate drying of individual partial layers as well as the application of the enamel coating in one step can be provided.

Bei der in Figur 2 gewählten Ansicht ist lediglich eine Kammer 9 der Flutvorrichtung 8 erkennbar. Der Verbrennungsmotor, also der Zylinderblock 3 weist möglicherweise aber mehr als eine Zylinderbohrung 1 auf, was im Sinne der Erfindung liegt. Insofern kann die Flutvorrichtung 8 auch mehr als die erkennbare eine Kammer 9 aufweisen, welche hintereinander und/oder nebeneinander angeordnet sein können. Dies ist abhängig von der Art des Verbrennungsmotors z.B. als Reihenmotor oder als V-Motor. Natürlich kann auch für jede Bohrung 1 eine separate Flutvorrichtung 8 mit einer einzigen Kammer 9 vorgesehen sein. Zielführend ist, wenn alle Bohrungen 1 gleichzeitig mit der Email-Beschichtung 2 versehen werden, was natürlich auch aufeinanderfolgend geschehen kann. Im Sinne der Wärmebehandlung ist jedoch ein möglichst gleichzeitiges Beschichten vorteilhaft.At the in Figure 2 Selected view, only a chamber 9 of the flood device 8 can be seen. However, the internal combustion engine, that is to say the cylinder block 3, may have more than one cylinder bore 1, which is within the meaning of the invention. To that extent The flood device 8 can also have more than the recognizable one chamber 9, which can be arranged one behind the other and / or next to one another. This depends on the type of internal combustion engine, for example as an in-line engine or as a V-engine. Of course, a separate flooding device 8 with a single chamber 9 can also be provided for each bore 1. It is expedient if all the bores 1 are provided with the enamel coating 2 at the same time, which can of course also be done in succession. In terms of heat treatment, however, coating that is as simultaneous as possible is advantageous.

Zielführend ist, wenn die gesamte Bohrung 1 mit der Email-Beschichtung 2 versehen wird.It is expedient if the entire bore 1 is provided with the enamel coating 2.

Anschließend wird eine Nachbehandlung der beschichteten Bohrung 1 vorgesehen, wobei sich die Email-Beschichtung mit dem Grundwerkstoff der Bohrung metallurgisch durch Phasenbildung verbindet. Mit dieser Nachbehandlung wird eine Wärmebehandlung mit anschließenden Abschrecken verbunden. Die beiden Behandlungen, also der Email-Einbrennvorgang, als auch die besagte Wärmebehandlung laufen im gleichen Temperatur-Zeit-Fenster ab, so dass sich durch diese Einbrenn- und Abschreckoperation also ein Zylinderblock mit erhöhter mechanischer Festigkeit sowie einer Zylinderbohrung mit guter Wärmedämmung und guter Verschleiß- und Korrosionsbeständigkeit ergibt. Die Wärmebehandlung ist zielführend als bainitische Grauguss Wärmebehandlung durchzuführen (AGI-Wärmebehandlung = Austempered Gray Iron Wärmebehandlung).After-treatment of the coated bore 1 is then provided, the enamel coating being metallurgically bonded to the base material of the bore by phase formation. This post-treatment combines a heat treatment with subsequent quenching. The two treatments, i.e. the enamel baking process, as well as the said heat treatment take place in the same temperature-time window, so that this baking and quenching operation results in a cylinder block with increased mechanical strength and a cylinder bore with good thermal insulation and good wear - and corrosion resistance results. The heat treatment is effective as a bainitic cast iron heat treatment (AGI heat treatment = Austempered Gray Iron heat treatment).

Anschließend kann die Email-Beschichtung 2 einem Finish z.B. mittels Diamant-Honleisten unterzogen werden. Dabei werden die in der Email-Beschichtung 2 vorhandenen Poren/Luftblasen 15 angeschnitten und offengelegt, wie in Figur 3 erkennbar ist. In Figur 3 ist die innere Oberfläche 4 der Bohrung 1, die Email-Beschichtung 2 sowohl die dazwischen angeordnete Übergangszone 16 erkennbar. Erkennbar ist in Figur 3 auch, dass es sich bei den besagten Poren/Luftblasen 15 nicht um miteinander verbundene Poren oder Porennester handelt wie bei einer thermisch aufgebrachten Spritzbeschichtung, so dass sich in den angeschnittenen und offengelegten Poren/Luftblasen der erfindungsgemäßen Email-Beschichtung ein hoher hydrodynamischer Druck aufbauen kann und der Ölfilm durch den Kolbenring nicht in verbundene Poren weggedrückt werden kann.The enamel coating 2 can then be subjected to a finish, for example using diamond honing stones. The pores / air bubbles 15 present in the enamel coating 2 are cut and exposed, as in Figure 3 is recognizable. In Figure 3 the inner surface 4 of the bore 1, the enamel coating 2 and the transition zone 16 arranged between them can be seen. Is recognizable in Figure 3 also that the pores / air bubbles 15 are not interconnected pores or pore nests as in the case of a thermally applied spray coating, so that a high hydrodynamic pressure can build up in the cut and exposed pores / air bubbles of the enamel coating according to the invention and the oil film cannot be pushed into connected pores by the piston ring.

Claims (12)

  1. Method for producing a coated inner surface (4) of a coated bore (1) of an internal combustion engine, said method comprising at least the steps of:
    - producing a main body (3) present in the blank;
    - drilling out the bore (1) and pre-machining the latter;
    - applying an enamel coating (2) to the inner surface (4) of the bore (1),
    - subsequently heat-treating the coated bore (1), wherein
    the enamel coating (2) is annealed together with the main body (3) made of GCI substrate material in a continuous furnace at a temperature of between 750°C and 900°C, preferably at T = 840°C, for 5 to 30 minutes, or
    the enamel coating (2) is annealed together with a main body (3) made of an aluminium alloy at a temperature of between 480°C and 560°C, preferably at T = 540°C, in a continuous furnace for 5 to 30 minutes,
    such that the enamel coating can bond in each case to the base material of the bore (1) metallurgically by phase formation; and
    - finishing the enamel coating (2) in such a manner that pores (15) present in the enamel coating (2) are cut or exposed.
  2. Method according to Claim 1, wherein
    the bore (1) is drilled out to an oversize of 1 to 2 mm in diameter by means of finish-boring.
  3. Method according to Claim 1 or 2, wherein
    the bore (1) is provided with a roughness of Ra 6 to 7 µm on the inner surface (4) thereof by turning spindles.
  4. Method according to one of the preceding claims, wherein
    the enamel coating (2) is applied to the inner surface (4) as an aqueous enamel slip and is then dried in a continuous furnace at T = 80 to 100°C, preferably at T = 90°C, for 8 to 12 minutes, preferably for 10 minutes.
  5. Method according to one of the preceding claims, wherein
    the enamel coating (2) is applied by means of a rotating application apparatus moving to and fro.
  6. Method according to one of Claims 1 to 4, wherein the enamel coating (2) is applied in a dipping operation with a flooding apparatus (8), the flooding apparatus (8) having at least one chamber (9) which has at least one outlet opening (10), with provision being made of a feed opening (11), which is adjoined by a line (12), such that aqueous enamel slip, which enters into the bore (1) emerging from the outlet opening (10) from the chamber (9), can be introduced into the chamber (9) .
  7. Method according to one of the preceding claims, wherein
    the entire bore (1) is provided with the enamel coating (2).
  8. Method according to one of the preceding claims, wherein
    the main body (3) is fed together with the dried enamel coating (2) to a heating apparatus, in which the main body (3) is heated to a temperature of 800 to 900°C and is kept at this temperature for 10 to 20 minutes, this being followed by rapid cooling.
  9. Cylinder block of an internal combustion engine with a bore (1) which has a coated inner surface (4), produced by means of a method according to one of the preceding claims,
    characterized in that
    the coating on the inner surface (4) of the bore (1) is an enamel coating (2).
  10. Cylinder block according to Claim 9,
    characterized in that
    the enamel coating comprises at least one of the glass-forming oxides selected from the group consisting of SiO2, B2O3, Na2O, K2O and Al2O3.
  11. Cylinder block according to Claim 9 or 10,
    characterized in that
    the cylinder block comprises a base material selected from the group of materials consisting of a magnesium alloy, an aluminium alloy, gray cast iron and cast steel.
  12. Cylinder barrel of a cylinder block according to one of Claims 9 to 11,
    characterized by
    an enamel coating (2) which has pores (15), wherein pores (15) present in the enamel coating (2) are cut or exposed after a finishing process.
EP15153047.4A 2014-02-06 2015-01-29 Method for coating a bore and cylinder block of an internal combustion engine Active EP2905455B1 (en)

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EP2905455A3 EP2905455A3 (en) 2015-11-18
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EP15153047.4A Active EP2905455B1 (en) 2014-02-06 2015-01-29 Method for coating a bore and cylinder block of an internal combustion engine

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US (1) US9759154B2 (en)
EP (1) EP2905455B1 (en)
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DE (1) DE102014202134A1 (en)

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WO2017074185A1 (en) * 2015-10-28 2017-05-04 Remeha B.V. Enamel powder and enamel slurry for producing an enamel coating on a metallic substrate, method for manufacturing an enamel slurry and use of the enamel coating for heat exchangers
KR20170127903A (en) * 2016-05-13 2017-11-22 현대자동차주식회사 Cylinder Liner for Insert Casting and Method for Manufacturing thereof
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US10400707B2 (en) * 2017-07-26 2019-09-03 GM Global Technology Operations LLC Method and system for processing an automotive engine block
CN108265294B (en) * 2018-02-28 2023-03-24 珠海格力电器股份有限公司 Plugging structure for lining process of inner container and lining process
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US10907569B2 (en) * 2019-06-19 2021-02-02 Ford Global Technologies, Llc Systems and methods for a cylinder bore coating fill material
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Publication number Publication date
US9759154B2 (en) 2017-09-12
US20150219039A1 (en) 2015-08-06
EP2905455A3 (en) 2015-11-18
CN104831278B (en) 2019-09-17
EP2905455A2 (en) 2015-08-12
CN104831278A (en) 2015-08-12
DE102014202134A1 (en) 2015-08-06

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