EP1460151A1 - Cylinder head for reciprocating internal combustion engines - Google Patents
Cylinder head for reciprocating internal combustion engines Download PDFInfo
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- EP1460151A1 EP1460151A1 EP03100714A EP03100714A EP1460151A1 EP 1460151 A1 EP1460151 A1 EP 1460151A1 EP 03100714 A EP03100714 A EP 03100714A EP 03100714 A EP03100714 A EP 03100714A EP 1460151 A1 EP1460151 A1 EP 1460151A1
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- Prior art keywords
- microarcoxidation
- cylinder head
- internal combustion
- coated
- areas
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/026—Anodisation with spark discharge
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- 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
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- 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
- F02B77/11—Thermal or acoustic insulation
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- 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
- F02F1/24—Cylinder heads
- F02F1/26—Cylinder heads having cooling means
- F02F1/36—Cylinder heads having cooling means for liquid cooling
- F02F1/38—Cylinder heads having cooling means for liquid cooling the cylinder heads being of overhead valve type
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- 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
- F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
- F02B2275/20—SOHC [Single overhead camshaft]
Definitions
- the present invention relates to the use of a method for coating metallic materials for cylinder heads of reciprocating internal combustion engines.
- the known method of microarcoxidation also known as plasma park or plasmaelectrolytic oxidation or microarc discharge oxidizing
- the invention further relates to a cylinder head for a reciprocating piston internal combustion engine, which has areas coated according to the microarcoxidation process, and to a method for producing cylinder heads.
- Today's reciprocating piston internal combustion engines consisting of at least one cylinder, containing a piston which sets a crankshaft in rotation via a connecting rod, and a cylinder head which closes off the combustion chamber formed by the piston and cylinder at the top.
- the cylinder head usually contains several gas exchange valves for the inlet or outlet of the combustion air or the combustion gases.
- State of the art is to use cylinder heads made of light metal or light metal alloys, since they have weight advantages and advantages in heat dissipation.
- light alloy cylinder heads have some areas in which the light metal does not meet the requirements of the company. So z. B. the area for guiding the gas exchange valves is reinforced by sleeves made of brass or sintered metal.
- the sealing surfaces of the gas exchange valves are usually reinforced by rings, the so-called valve seat rings, made of hardened steel alloys.
- microarcoxidation of light metals is e.g. B. from WO 00/05493, from US 6,197,178 or the SAE paper from V.D.N. Rao, H.A. Cikanek, B.A. Boyer, L.N. Lesnevsky, N.M. Tchernovsky, N.V. Tjurin "Friction and wear characteristics of micro-arc oxidation coating for light weight, wear resistant, powertrain component application" SAE paper 970022; Known in 1997. It is also known to use the microarcoxidation process for coating cylinders and pistons.
- a prerequisite for the microarcoxidation process is an acidic or basic electrolyte bath with a specific aqueous electrolyte into which one or more workpieces are immersed.
- the workpiece or workpieces form the anode, while the container usually represents the cathode.
- a voltage is applied to the workpiece (s), here a cylinder head, until tiny arcs are formed at certain current levels. After some time, this leads to an oxidized surface layer of usually approximately 20 to 500 thousandths of a millimeter. This surface layer is characterized by significantly increased hardness, lower friction and better wear resistance.
- the outermost porous area can be mechanically removed before the first use.
- the heat conduction of the oxidized layer is significantly reduced compared to the base material, so that a certain thermal insulation is achieved by comparison.
- microarcoxidation process is now applied to different areas of a cylinder head, some component improvements can be achieved, such as. B. better thermal insulation or increased wear resistance. Areas in which the surface should not be oxidized must be covered during the application of the process.
- cylinder heads made of light metal from reciprocating piston internal combustion engines are coated by the previously described method for microarcoxidation.
- the microarcoxidation process creates an oxidized surface layer of approx. 20 to 500 thousandths of a millimeter. This surface layer has significantly different properties than the base material. So z. B. significantly increases the hardness, increases the wear resistance and reduces the thermal conductivity. These properties can be used to advantage on a cylinder head that has different tasks depending on the area.
- the sealing surfaces of a cylinder head to the gas exchange valves are therefore coated by means of microarcoxidation. It is state of the art to use so-called valve seat rings for light metal cylinder heads for these sealing surfaces. This is necessary because the light metal does not withstand the stress caused by the impact of the closing gas exchange valves on the sealing surfaces in the long run. Valve seat rings are therefore usually made of hardened steel materials. By coating these sealing surfaces by means of microarcoxidation, the sealing surfaces of the cylinder head are hardened in such a way that the use of valve seat rings becomes superfluous. This saves several processing steps on the cylinder head and the manufacture and assembly of the valve seat rings. It is also advantageous here that the coated areas are significantly thinner than the valve seat rings used otherwise, so that it is possible to change the cylinder head so that the cooling water channels come closer to the valves.
- Another application according to the invention of the microarcoxidation method on the cylinder head is suitable for the valve guides of the gas exchange valves.
- the light metal material of cylinder heads usually does not meet the requirements placed on a plain bearing guide. Therefore, guide sleeves made of alloys or sintered materials are used for guiding the gas exchange valves usually made of steel materials. These offer sufficient hardness, certain emergency running properties in the absence or insufficient supply of the operating lubricant and / or a certain porosity for storing small amounts of lubricant in order to ensure emergency running properties.
- the guides for gas exchange valves are worked out directly from the light metal material of the cylinder head and then coated with the microarcoxidation process, the properties required above for guiding gas exchange valves result, so that the use of separate guide sleeves becomes superfluous.
- the intake and exhaust ports of a cylinder head using the microarcoxidation process.
- the channels within a cylinder head that guide the combustion air into the cylinder or the exhaust gases out of the cylinder are referred to as intake and exhaust channels.
- the surface layer created by the microarcoxidation process has poorer thermal conductivity than the light metal cylinder head material. This thermal insulation, albeit low, is useful for the combustion air inlet duct, since the combustion air is less heated when the engine is warm and because the colder air has a lower density, the filling of the cylinder with combustion air is improved. It also makes sense to coat the outlet channels. Due to the insulating effect, they cool down Exhaust gases less so that a catalytic exhaust gas cleaning device, which is usually connected downstream, reaches its ignition temperature more quickly.
- valve webs are to be coated between two valve seats on the cylinder head.
- This area is usually subjected to a special thermal stress, which results from the thin wall between the exhaust gas and the intake duct. Additional insulation of this area by coating this area using the microarcoxidation process is therefore advantageous.
- the invention further relates to a cylinder head which has a coating produced by the microarcoxidation process on at least one of the regions described above.
- a method according to the invention is proposed in which a cylinder head is coated on at least one of the areas described above. Areas that should not be coated are covered by suitable measures. Depending on requirements, one or more areas of a cylinder head or the entire cylinder head can be coated in the manner described.
- FIG. 1 shows a section of a section through a reciprocating piston internal combustion engine 1.
- a cylinder head 2, a part of a cylinder block 3 and a cylinder 4 in which a piston 5 is movably arranged can be seen.
- the piston 5 forms together with the cylinder 4 and the Cylinder head 2 a combustion chamber 6.
- Combustion air passes through an inlet duct 10 through one of the two gas exchange valves 7, 7 'into the combustion chamber 6, while the exhaust gases leave the combustion chamber through the other of the two gas exchange valves 7, 7' and are then passed on through the exhaust duct 11 ,
- Valve seat rings 9, 9 ' are embedded in the cylinder head 2, on which sealing surfaces for the gas exchange valves 7, 7' are formed.
- a light metal cylinder head 2 is coated in the area of the sealing surfaces of the gas exchange valves 7, 7 'by means of microarcoxidation.
- Valve seat rings 9, 9 'made of usually hardened steel material are usually used here, since in this area the gas exchange valves 7, 7' hit the cylinder head at high speed when they are closed. If, on the other hand, these areas have been coated by microarcoxidation as described, the resulting layer can meet the requirements, so that the valve seat rings 9, 9 'can be omitted.
- the inlet and outlet channels 10, 11 of an internal combustion engine 1 can also be advantageous to coat the inlet and outlet channels 10, 11 of an internal combustion engine 1.
- the coating has a lower thermal conductivity than the base material. This has the advantage on the inlet side that the combustion air is heated up less, so that cooler, therefore denser and therefore more combustion air can get into the combustion chamber 6. On the outlet side, this slight insulation effect has the advantage that the exhaust gases do not cool down as quickly and therefore z.
- a catalytic exhaust gas treatment device reaches its ignition temperature faster.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Electrochemistry (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Cylinder Crankcases Of Internal Combustion Engines (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Abstract
Description
Die vorliegende Erfindung betrifft die Verwendung eines Verfahrens zum Beschichten von metallischen Werkstoffen für Zylinderköpfe von Hubkolbenbrennkraftmaschinen. Dabei wird das bekannte Verfahren der Microarcoxidation (auch bekannt als Plasmaspark bzw. Plasmaelectrolytic Oxidation oder Microarc discharge oxidizing) von Leichtmetallen dazu verwendet, die Oberflächeneigenschaften eines Zylinderkopfes einer Hubkolbenbrennkraftmaschine zu verbessern. Die Erfindung betrifft ferner einen Zylinderkopf für eine Hubkolbenbrennkraftmaschine, der nach dem Microarcoxidationsverfahren beschichtete Bereiche aufweist sowie ein Verfahren zur Herstellung von Zylinderköpfen.The present invention relates to the use of a method for coating metallic materials for cylinder heads of reciprocating internal combustion engines. The known method of microarcoxidation (also known as plasma park or plasmaelectrolytic oxidation or microarc discharge oxidizing) of light metals is used to improve the surface properties of a cylinder head of a reciprocating piston internal combustion engine. The invention further relates to a cylinder head for a reciprocating piston internal combustion engine, which has areas coated according to the microarcoxidation process, and to a method for producing cylinder heads.
Heutige Hubkolbenbrennkraftmaschinen, bestehend aus mindestens einem Zylinder, enthaltend einen Kolben, der über einen Pleuel eine Kurbelwelle in Rotation versetzt, und einen Zylinderkopf, der den mittels Kolben und Zylinder gebildeten Verbrennungsraum nach oben abschließt. Der Zylinderkopf enthält üblicherweise mehrere Gaswechselventile für den Einlaß bzw. Auslaß der Verbrennungsluft bzw. der Verbrennungsgase. Stand der Technik ist es, Zylinderköpfe aus Leichtmetall oder Leichtmetallegierungen zu verwenden, da sie Gewichtsvorteile und Vorteile in der Wärmeabfuhr aufweisen. Allerdings haben Leichtmetallzylinderköpfe einige Bereiche, in denen das Leichtmetall den Anforderungen des Betriebes nicht genügt. So wird z. B. der Bereich zur Führung der Gaswechselventile durch Hülsen aus Messing oder Sintermetall verstärkt. Auch die Dichtflächen der Gaswechselventile werden üblicherweise durch Ringe, die sogenannten Ventilsitzringe, aus gehärteten Stahllegierungen verstärkt.Today's reciprocating piston internal combustion engines, consisting of at least one cylinder, containing a piston which sets a crankshaft in rotation via a connecting rod, and a cylinder head which closes off the combustion chamber formed by the piston and cylinder at the top. The cylinder head usually contains several gas exchange valves for the inlet or outlet of the combustion air or the combustion gases. State of the art is to use cylinder heads made of light metal or light metal alloys, since they have weight advantages and advantages in heat dissipation. However, light alloy cylinder heads have some areas in which the light metal does not meet the requirements of the company. So z. B. the area for guiding the gas exchange valves is reinforced by sleeves made of brass or sintered metal. The sealing surfaces of the gas exchange valves are usually reinforced by rings, the so-called valve seat rings, made of hardened steel alloys.
Das Verfahren der Microarcoxidation von Leichtmetallen ist z. B. aus der WO 00/05493, aus der US 6,197,178 oder dem SAE-Papier von V.D.N. Rao, H.A. Cikanek, B.A. Boyer, L.N. Lesnevsky, N.M. Tchernovsky, N.V. Tjurin "Friction and wear characteristics of micro-arc oxidation coating for light weight, wear resistant, powertrain component application" SAE paper 970022; 1997 bekannt. Bekannt ist außerdem das Microarcoxidationsverfahren zur Beschichtung von Zylindern und Kolben anzuwenden.The process of microarcoxidation of light metals is e.g. B. from WO 00/05493, from US 6,197,178 or the SAE paper from V.D.N. Rao, H.A. Cikanek, B.A. Boyer, L.N. Lesnevsky, N.M. Tchernovsky, N.V. Tjurin "Friction and wear characteristics of micro-arc oxidation coating for light weight, wear resistant, powertrain component application" SAE paper 970022; Known in 1997. It is also known to use the microarcoxidation process for coating cylinders and pistons.
Voraussetzungen für das Microarcoxidationsverfahren ist ein saures oder basisches Elektrolytbad mit einem spezifischen wäßrigen Elektrolyten, in das ein oder mehrere Werkstücke eingetaucht werden. Das oder die Werkstücke bilden die Anode während üblicherweise der Behälter die Kathode darstellt. An das oder die Werkstücke, hier ein Zylinderkopf, wird eine Spannung angelegt, bis sich winzige Lichtbögen bilden, bei bestimmten sich einstellenden Stromstärken. Dies führt nach einiger Zeit zu einer oxidierten Oberflächenschicht von üblicherweise ca. 20 bis 500 tausendstel Millimeter. Diese Oberflächenschicht zeichnet sich durch eine deutliche erhöhte Härte, durch geringere Reibung sowie eine bessere Verschleißfestigkeit aus. Der äußerste entstehende poröse Bereich kann vor dem ersten Einsatz mechanisch entfernt werden.
Außerdem ist die Wärmeleitung der oxidierten Schicht deutlich vermindert gegenüber dem Grundmaterial, so daß vergleichsweise eine gewisse thermische Isolierung erreicht wird.A prerequisite for the microarcoxidation process is an acidic or basic electrolyte bath with a specific aqueous electrolyte into which one or more workpieces are immersed. The workpiece or workpieces form the anode, while the container usually represents the cathode. A voltage is applied to the workpiece (s), here a cylinder head, until tiny arcs are formed at certain current levels. After some time, this leads to an oxidized surface layer of usually approximately 20 to 500 thousandths of a millimeter. This surface layer is characterized by significantly increased hardness, lower friction and better wear resistance. The outermost porous area can be mechanically removed before the first use.
In addition, the heat conduction of the oxidized layer is significantly reduced compared to the base material, so that a certain thermal insulation is achieved by comparison.
Wird nun das Microarcoxidationsverfahren auf verschiedene Bereiche eines Zylinderkopfes angewandt, so lassen sich einige Bauteilverbesserungen erreichen, wie z. B. bessere thermische Isolierung oder erhöhte Verschleißfestigkeit. Bereiche, in denen die Oberfläche nicht oxidiert werden soll, müssen während der Anwendung des Verfahrens abgedeckt sein.If the microarcoxidation process is now applied to different areas of a cylinder head, some component improvements can be achieved, such as. B. better thermal insulation or increased wear resistance. Areas in which the surface should not be oxidized must be covered during the application of the process.
Es ist daher Aufgabe dieser Erfindung einen Zylinderkopf einer Hubkolbenbrennkraftmaschine durch Verwendung eines Verfahrens zur Microarcoxidation von Leichtmetallen so zu verbessern, daß er kostengünstiger hergestellt werden kann, wobei gleichzeitig die Lebensdauer heraufgesetzt wird. Dies wird durch die Verwendung des Verfahren gemäß des Hauptanspruchs 1 erreicht. Vorteilhafte Ausgestaltungen sind in den Unteransprüchen enthalten.It is therefore an object of this invention to improve a cylinder head of a reciprocating piston internal combustion engine by using a method for microarcoxidation of light metals in such a way that it can be produced more cost-effectively, with the service life being increased at the same time. This is achieved by using the method according to
Erfindungsgemäß werden Zylinderköpfe aus Leichtmetall von Hubkolbenbrennkraftmaschinen durch das zuvor beschriebene Verfahren zur Microarcoxidation beschichtet. Wie zuvor erwähnt entsteht durch das Microarcoxidationsverfahren eine oxidierte Oberflächenschicht von ca. 20 bis 500 tausendstel Millimeter. Diese Oberflächenschicht weist deutlich andere Eigenschaften als das Grundmaterial auf. So ist z. B. die Härte wesentlich erhöht, die Verschleißfestigkeit heraufgesetzt und die Wärmeleitfähigkeit vermindert. Diese Eigenschaften können an einem Zylinderkopf, der je nach Bereich unterschiedliche Aufgaben hat, vorteilhaft genutzt werden.According to the invention, cylinder heads made of light metal from reciprocating piston internal combustion engines are coated by the previously described method for microarcoxidation. As mentioned before, the microarcoxidation process creates an oxidized surface layer of approx. 20 to 500 thousandths of a millimeter. This surface layer has significantly different properties than the base material. So z. B. significantly increases the hardness, increases the wear resistance and reduces the thermal conductivity. These properties can be used to advantage on a cylinder head that has different tasks depending on the area.
Erfindungsgemäß werden daher die Dichtflächen eines Zylinderkopfes zu den Gaswechselventilen mittels Microarcoxidation beschichtet. Stand der Technik ist es, bei Leichtmetallzylinderköpfen für diese Dichtflächen sogenannte Ventilsitzringe zu verwenden. Dies ist nötig, da das Leichtmetall der Belastung, die durch das Aufprallen der schließenden Gaswechselventile auf die Dichtflächen entsteht, auf Dauer nicht standhält. Ventilsitzringe sind daher üblicherweise aus gehärteten Stahlwerkstoffen hergestellt. Durch Beschichtung dieser Dichtflächen mittels Microarcoxidation werden die Dichtflächen des Zylinderkopfes derart gehärtet, daß die Verwendung von Ventilsitzringen überflüssig wird. Dies spart mehrere Bearbeitungsschritte am Zylinderkopf sowie die Fertigung und Montage der Ventilsitzringe. Vorteilhaft ist hier auch, daß die beschichteten Bereiche deutlich dünner sind als die sonst verwendeten Ventilsitzringe, so daß es möglich ist den Zylinderkopf so zu verändern, daß die Kühlwasserkanäle näher an die Ventile heranreichen.According to the invention, the sealing surfaces of a cylinder head to the gas exchange valves are therefore coated by means of microarcoxidation. It is state of the art to use so-called valve seat rings for light metal cylinder heads for these sealing surfaces. This is necessary because the light metal does not withstand the stress caused by the impact of the closing gas exchange valves on the sealing surfaces in the long run. Valve seat rings are therefore usually made of hardened steel materials. By coating these sealing surfaces by means of microarcoxidation, the sealing surfaces of the cylinder head are hardened in such a way that the use of valve seat rings becomes superfluous. This saves several processing steps on the cylinder head and the manufacture and assembly of the valve seat rings. It is also advantageous here that the coated areas are significantly thinner than the valve seat rings used otherwise, so that it is possible to change the cylinder head so that the cooling water channels come closer to the valves.
Eine weitere erfindungsgemäße Anwendung des Microarcoxidationsverfahrens am Zylinderkopf bietet sich für die Ventilführungen der Gaswechselventile an. Üblicherweise erfüllt der Leichtmetallwerkstoff von Zylinderköpfen nicht die Anforderungen, die an eine Gleitlagerführung gestellt werden. Daher werden für die Führung der üblicherweise aus Stahlwerkstoffen hergestellten Gaswechselventile Führungshülsen aus Legierungen oder Sinterwerkstoffen eingesetzt. Diese bieten eine ausreichende Härte, gewisse Notlaufeigenschaften bei Fehlen oder Unterversorgung des Betriebsschmierstoffes und/oder eine gewisse Porosität zur Speicherung geringer Mengen von Schmierstoff, um so Notlaufeigenschaften sicherzustellen. Werden nun erfindungsgemäß die Führungen für Gaswechselventile direkt aus dem Leichtmetallwerkstoff des Zylinderkopfes herausgearbeitet und anschließen mit dem Microarcoxidationsverfahren beschichtet, so ergeben sich die erforderlichen oben aufgeführten Eigenschaften zur Führung von Gaswechselventilen, so daß der Einsatz von separaten Führungshülsen überflüssig wird.Another application according to the invention of the microarcoxidation method on the cylinder head is suitable for the valve guides of the gas exchange valves. The light metal material of cylinder heads usually does not meet the requirements placed on a plain bearing guide. Therefore, guide sleeves made of alloys or sintered materials are used for guiding the gas exchange valves usually made of steel materials. These offer sufficient hardness, certain emergency running properties in the absence or insufficient supply of the operating lubricant and / or a certain porosity for storing small amounts of lubricant in order to ensure emergency running properties. If, according to the invention, the guides for gas exchange valves are worked out directly from the light metal material of the cylinder head and then coated with the microarcoxidation process, the properties required above for guiding gas exchange valves result, so that the use of separate guide sleeves becomes superfluous.
Erfindungsgemäß ist es weiterhin vorteilhaft, die Ein- und Auslaßkanäle eines Zylinderkopfes mittels des Microarcoxidationsverfahrens zu beschichten. Als Ein- bzw. Auslaßkanäle werden die Kanäle innerhalb eines Zylinderkopfes bezeichnet, die die Verbrennungsluft in den Zylinder, bzw. die Abgase aus dem Zylinder hinein- bzw. hinausleiten. Wie zuvor beschrieben besitzt die durch das Microarcoxidationsverfahren entstandene Oberflächenschicht eine schlechtere Wärmeleitfähigkeit als der Leichtmetallzylinderkopfwerkstoff. Diese wenn auch geringe thermische Isolation ist für den Verbrennungslufteinlaßkanal sinnvoll, da die Verbrennungsluft bei betriebswarmen Motor weniger aufgeheizt wird und dadurch, daß kältere Luft eine geringere Dichte besitzt, die Füllung des Zylinders mit Verbrennungsluft verbessert wird. Es ist außerdem sinnvoll, die Auslaßkanäle zu beschichten. Durch die Isolationswirkung kühlen sich die Abgase weniger ab, so daß eine üblicherweise nachgeschaltete katalytische Abgasreinigungsvorrichtung schneller ihre Zündtemperatur erreicht.According to the invention, it is also advantageous to coat the intake and exhaust ports of a cylinder head using the microarcoxidation process. The channels within a cylinder head that guide the combustion air into the cylinder or the exhaust gases out of the cylinder are referred to as intake and exhaust channels. As described above, the surface layer created by the microarcoxidation process has poorer thermal conductivity than the light metal cylinder head material. This thermal insulation, albeit low, is useful for the combustion air inlet duct, since the combustion air is less heated when the engine is warm and because the colder air has a lower density, the filling of the cylinder with combustion air is improved. It also makes sense to coat the outlet channels. Due to the insulating effect, they cool down Exhaust gases less so that a catalytic exhaust gas cleaning device, which is usually connected downstream, reaches its ignition temperature more quickly.
Eine weitere vorteilhafte Gestaltung der Erfindung sieht vor, die sind zwischen zwei Ventilsitzen am Zylinderkopf ergebenden Stege, die sogenannten Ventilstege zu beschichten. Dieser Bereich ist üblicherweise einem besonderen thermischen Streß ausgesetzt, der aus der dünnen Wandung zwischen Abgasund Einlaßkanal resultiert. Eine zusätzliche Isolation dieses Bereiches durch Beschichten dieses Bereiches mittels des Microarcoxidationsverfahrens ist daher vorteilhaft.A further advantageous embodiment of the invention provides that the so-called valve webs are to be coated between two valve seats on the cylinder head. This area is usually subjected to a special thermal stress, which results from the thin wall between the exhaust gas and the intake duct. Additional insulation of this area by coating this area using the microarcoxidation process is therefore advantageous.
Die Erfindung betrifft weiterhin einen Zylinderkopf, der eine das Microarcoxidationsverfahren erzeugte Beschichtung an mindestens einem der zuvor beschriebenen Bereiche aufweist.The invention further relates to a cylinder head which has a coating produced by the microarcoxidation process on at least one of the regions described above.
Weiterhin wird ein erfindungsgemäßes Verfahren vorgeschlagen, bei dem ein Zylinderkopf an mindestens einem der zuvor beschriebenen Bereiche beschichtet wird. Bereiche, die nicht beschichtet werden sollen, werden durch geeignete Maßnahmen abgedeckt. So lassen sich je nach Bedarf ein oder mehrere Bereiche eines Zylinderkopfes oder der gesamte Zylinderkopf in der beschriebenen Weise beschichten.Furthermore, a method according to the invention is proposed in which a cylinder head is coated on at least one of the areas described above. Areas that should not be coated are covered by suitable measures. Depending on requirements, one or more areas of a cylinder head or the entire cylinder head can be coated in the manner described.
Die Erfindung wird anhand der einzigen Zeichnung näher erläutert. Es zeigt:
- Fig. 1
- Einen Ausschnitt eines Schnittes durch eine Hubkoibenbrennkraftmaschine
- Fig. 1
- A section of a section through a reciprocating-piston internal combustion engine
Figur 1 zeigt einen Ausschnitt eines Schnittes durch eine Hubkolbenbrennkraftmaschine 1. Zu erkennen sind ein Zylinderkopf 2, ein Teil eines Zylinderblockes 3 und ein Zylinder 4, in dem ein Kolben 5 beweglich angeordnet ist. Der Kolben 5 bildet zusammen mit dem Zylinder 4 und dem Zylinderkopf 2 einen Brennraum 6. Verbrennungsluft gelangt über einen Einlaßkanal 10 durch eines der beiden Gaswechselventile 7, 7' in den Brennraum 6, während die Abgase den Brennraum durch das andere der beiden Gaswechselventile 7, 7' verlassen und dann durch den Auslaßkanal 11 weitergeleitet werden. Die Gaswechselventile 7, 7' sind üblicherweise in Ventilführungen 8, 8' beweglich angeordnet. In den Zylinderkopf 2 sind Ventilsitzringe 9, 9' eingelassen, an denen Dichtflächen für die Gaswechselventile 7, 7' ausgebildet sind.FIG. 1 shows a section of a section through a reciprocating piston
Erfindungsgemäß wird ein Leichtmetallzylinderkopf 2 im Bereich der Dichtflächen der Gaswechselventile 7,7' mittels Microarcoxidation beschichtet. Üblicherweise sind hier Ventilsitzringe 9, 9' aus üblicherweise gehärtetem Stahlwerkstoff in Einsatz, da in diesem Bereich die Gaswechselventile 7, 7' beim Schließen mit hoher Geschwindigkeit auf den Zylinderkopf prallen. Sind dagegen diese Bereiche wie beschrieben durch Microarcoxidation beschichtet worden, so ist die entstandene Schicht den Anforderungen gewachsen, so daß die Ventilsitzringe 9, 9' entfallen können.According to the invention, a light
Ähnliches gilt für die Bereiche der Ventilführungen 8, 8', in denen die Gaswechselventile 7, 7' gelagert sind. Üblicherweise erfüllt der Leichtmetallwerkstoff des Zylinderkopfes 2 nicht die Anforderungen, die an eine Lagerung der Gaswechselventile 7, 7' gestellt werden: Die Gleitlagerung der Gaswechselventile 7, 7' muß ausreichend verschleißfest sein, aber auch Notlaufeigenschaften aufweisen, da es beim Anlassen einer Brennkraftmaschine 1 einige Sekunden dauert, bis der Schmierstoff an alle Lagerstellen vordringt. Erfindungsgemäß wird nun dieser Bereich der Lagerung der Gaswechselventile 7, 7' durch Microarcoxidation mit einer oxidierten Oberflächenschicht überzogen. Diese Schicht weist eine genügende Verschleißfestigkeit aus, ist aber auch leicht porös, so daß etwas Öl zurückgehalten werden kann, was wiederum die gewünschte Notlaufeigenschaft bietet. Auf separate Ventilführungen 8, 8' kann daher verzichtet werden. Eine zusätzliche Beschichtung durch PTFE (Teflon) oder Gleitlack ist denkbar.The same applies to the areas of the valve guides 8, 8 'in which the gas exchange valves 7, 7' are mounted. Usually, the light metal material of the
Erfindungsgemäß, kann es auch vorteilhaft sein, die Ein- bzw. Auslaßkanäle 10, 11 eines Verbrennungsmotors 1 zu beschichten. Die Beschichtung hat eine geringere Wärmeleitfähigkeit als das Grundmaterial. Dies hat auf der Einlaßseite den Vorteil, daß die Verbrennungsluft weniger aufgeheizt wird, so daß kühlere, damit dichtere und daher mehr Verbrennungsluft in den Brennraum 6 gelangen kann. Auf der Auslaßseite bringt diese leichte Isolationswirkung den Vorteil, daß die Abgase nicht so schnell abkühlen und daher z. B. eine katalytische Abgasbehandlungseinrichtung schneller ihre Zündtemperatur erreicht.According to the invention, it can also be advantageous to coat the inlet and
Auch eine thermische Isolierung der Ventilstege 12 ist sinnvoll, da diese Bereiche hohen Temperaturdifferenzen und starker mechanischer Belastung ausgesetzt sind.Thermal insulation of the
Claims (7)
dadurch gekennzeichnet, daß
die Zylinderköpfe (2) in den Kontaktbereichen der Gaswechselventilteller (9, 9') beschichtet werden.Use of a method for microarcoxidation according to claim 1,
characterized in that
the cylinder heads (2) in the contact areas of the gas exchange valve plates (9, 9 ') are coated.
dadurch gekennzeichnet, daß
die Zylinderköpfe (2) in den Kontaktbereichen der Gaswechselventilführungen (8, 8') beschichtet werden.Use of a method for microarcoxidation according to claim 1,
characterized in that
the cylinder heads (2) in the contact areas of the gas exchange valve guides (8, 8 ') are coated.
dadurch gekennzeichnet, daß
die Ein- und Auslaßkanäle (10, 11) beschichtet werden.Use of a method for microarcoxidation according to claim 1,
characterized in that
the inlet and outlet channels (10, 11) are coated.
dadurch gekennzeichnet, daß
die Ventilstege beschichtet werden.Use of a method for microarcoxidation according to claim 1,
characterized in that
the valve webs are coated.
dadurch gekennzeichnet, daß
der Zylinderkopf (2) beschichtete Bereiche nach mindestens einem der Ansprüche 1 bis 5 aufweist.Cylinder head for a reciprocating piston internal combustion engine (1)
characterized in that
the cylinder head (2) has coated areas according to at least one of claims 1 to 5.
dadurch gekennzeichnet, daß
die nicht in den Ansprüchen 2 bis 5 genannten Bereiche während der Microarcoxidation abgedeckt werden, so daß in diesen Bereichen keine Oberfiächenbeschichtung erfolgt.Process for coating cylinder heads (2) for reciprocating internal combustion engines (1) by means of microarcoxidation
characterized in that
the areas not mentioned in claims 2 to 5 are covered during the microarcoxidation, so that no surface coating takes place in these areas.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP03100714A EP1460151A1 (en) | 2003-03-19 | 2003-03-19 | Cylinder head for reciprocating internal combustion engines |
JP2004067961A JP2004340130A (en) | 2003-03-19 | 2004-03-10 | Cylinder head of reciprocating piston internal combustion engine |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP03100714A EP1460151A1 (en) | 2003-03-19 | 2003-03-19 | Cylinder head for reciprocating internal combustion engines |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1460151A1 true EP1460151A1 (en) | 2004-09-22 |
Family
ID=32799022
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP03100714A Withdrawn EP1460151A1 (en) | 2003-03-19 | 2003-03-19 | Cylinder head for reciprocating internal combustion engines |
Country Status (2)
Country | Link |
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EP (1) | EP1460151A1 (en) |
JP (1) | JP2004340130A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1657326A1 (en) * | 2004-11-16 | 2006-05-17 | Aisin Seiki Kabushiki Kaisha | Aluminium- or magnesium-piston containing 12-25% Silicon, the surface of which is oxidised by microarc-oxidation |
CN105648495A (en) * | 2016-03-22 | 2016-06-08 | 湖北韩泰智能设备有限公司 | Micro-arc oxidation device for aluminum piston |
DE102019006040A1 (en) * | 2019-08-27 | 2021-03-04 | Man Truck & Bus Se | Cooling-optimized cylinder head |
Citations (8)
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EP0462850A1 (en) * | 1990-06-19 | 1991-12-27 | Automobiles Peugeot | Method of making aluminium alloy castings containing an insert and cylinder head of internal combustion engine obtained thereby |
DE19506656A1 (en) * | 1995-02-25 | 1996-08-29 | Audi Ag | Coating light metal surface with ceramic layer |
US5616229A (en) * | 1994-06-01 | 1997-04-01 | Almag Al | Process for coating metals |
US5720866A (en) * | 1996-06-14 | 1998-02-24 | Ara Coating, Inc. | Method for forming coatings by electrolyte discharge and coatings formed thereby |
EP0884405A2 (en) * | 1997-05-24 | 1998-12-16 | Anatoli J. Prof. Dr. Vassiliev | Process for obtaining hard oxide layers on the surface of a light metal based substrate |
WO2000005493A1 (en) * | 1998-07-23 | 2000-02-03 | Fedor Dmitrievich Muravlev | Internal combustion engine, part thereof comprising a surface coating, and method and devices for producing said part |
DE19848590A1 (en) * | 1998-10-21 | 2000-04-27 | Igor Groza | Coating process for machinery smooth metallic surface uses an electrolyte comprising a fullerene and/or a fluorine or organofluorine compound |
US6197178B1 (en) | 1999-04-02 | 2001-03-06 | Microplasmic Corporation | Method for forming ceramic coatings by micro-arc oxidation of reactive metals |
-
2003
- 2003-03-19 EP EP03100714A patent/EP1460151A1/en not_active Withdrawn
-
2004
- 2004-03-10 JP JP2004067961A patent/JP2004340130A/en active Pending
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0462850A1 (en) * | 1990-06-19 | 1991-12-27 | Automobiles Peugeot | Method of making aluminium alloy castings containing an insert and cylinder head of internal combustion engine obtained thereby |
US5616229A (en) * | 1994-06-01 | 1997-04-01 | Almag Al | Process for coating metals |
DE19506656A1 (en) * | 1995-02-25 | 1996-08-29 | Audi Ag | Coating light metal surface with ceramic layer |
US5720866A (en) * | 1996-06-14 | 1998-02-24 | Ara Coating, Inc. | Method for forming coatings by electrolyte discharge and coatings formed thereby |
EP0884405A2 (en) * | 1997-05-24 | 1998-12-16 | Anatoli J. Prof. Dr. Vassiliev | Process for obtaining hard oxide layers on the surface of a light metal based substrate |
WO2000005493A1 (en) * | 1998-07-23 | 2000-02-03 | Fedor Dmitrievich Muravlev | Internal combustion engine, part thereof comprising a surface coating, and method and devices for producing said part |
DE19848590A1 (en) * | 1998-10-21 | 2000-04-27 | Igor Groza | Coating process for machinery smooth metallic surface uses an electrolyte comprising a fullerene and/or a fluorine or organofluorine compound |
US6197178B1 (en) | 1999-04-02 | 2001-03-06 | Microplasmic Corporation | Method for forming ceramic coatings by micro-arc oxidation of reactive metals |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1657326A1 (en) * | 2004-11-16 | 2006-05-17 | Aisin Seiki Kabushiki Kaisha | Aluminium- or magnesium-piston containing 12-25% Silicon, the surface of which is oxidised by microarc-oxidation |
CN105648495A (en) * | 2016-03-22 | 2016-06-08 | 湖北韩泰智能设备有限公司 | Micro-arc oxidation device for aluminum piston |
CN105648495B (en) * | 2016-03-22 | 2018-03-20 | 湖北韩泰智能设备有限公司 | Aluminum piston micro-arc oxidation device |
DE102019006040A1 (en) * | 2019-08-27 | 2021-03-04 | Man Truck & Bus Se | Cooling-optimized cylinder head |
Also Published As
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JP2004340130A (en) | 2004-12-02 |
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