EP0084385A1 - Light-metal piston - Google Patents

Light-metal piston Download PDF

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Publication number
EP0084385A1
EP0084385A1 EP83200003A EP83200003A EP0084385A1 EP 0084385 A1 EP0084385 A1 EP 0084385A1 EP 83200003 A EP83200003 A EP 83200003A EP 83200003 A EP83200003 A EP 83200003A EP 0084385 A1 EP0084385 A1 EP 0084385A1
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EP
European Patent Office
Prior art keywords
piston
combustion
light metal
iron layer
metal piston
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.)
Granted
Application number
EP83200003A
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German (de)
French (fr)
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EP0084385B1 (en
Inventor
Wilfried Sander
Klaus Schellmann
Gunder Dr. Essig
Erich Dr. Wacker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kolbenschmidt AG
Original Assignee
Kolbenschmidt AG
Karl Schmidt GmbH
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Application filed by Kolbenschmidt AG, Karl Schmidt GmbH filed Critical Kolbenschmidt AG
Publication of EP0084385A1 publication Critical patent/EP0084385A1/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
    • F02F3/00—Pistons 
    • F02F3/10—Pistons  having surface coverings
    • F02F3/12—Pistons  having surface coverings on piston heads

Definitions

  • the invention relates to a light metal piston for internal combustion engines, in particular for Otto engines, the surface of which is exposed to combustion, but at least the piston crown and / or top land, are provided in whole or in part with reinforcement.
  • the knock in the gasoline engine is caused by the fact that thermodynamic and chemical conditions are generated in the tail gas - that is the proportion of the mixture not yet recorded by the combustion - due to the pressure and temperature increase due to the compression movement of the piston and the combustion that has already occurred in part of the charge , which lead to a sudden release of the energy contained in the tail gas.
  • Typical pressure vibrations of high frequency acting on the walls of the combustion chamber are measured, which are superimposed on the normal pressure curve.
  • the temperature vibrations that can be measured on the combustion chamber surfaces are significantly higher during knocking combustion during the working cycle, without an increase, for example, in the mean piston crown temperature, which can be seen to exceed the temperature increase corresponding to the changed course of the burn-through function over time.
  • This object is achieved in such a way that the surfaces of the piston exposed to combustion, but at least the piston crown and / or the top land, are completely or partially reinforced according to the invention with a 5 to 30 ⁇ m thick electrochemically deposited iron layer.
  • the iron layer t can be replaced entirely or partially by a nickel layer.
  • the iron layer primarily exerts a shielding effect, in particular by keeping the high-frequency temperature fluctuations and corrosive stress components away from the light metal of the piston body. But it is also essential that the iron layer itself withstands the stresses caused by knocking combustion due to its high strength, its homogeneous structure, the smooth surface and the high adhesive strength on the light metal. The totality of these properties cannot be achieved with other coatings, for example a hard anodized layer of comparable thickness (DE-PS 25 07 899) produced by anodic oxidation on the piston head, which cannot prevent damage to the light metal piston caused by knocking combustion, although the hard anodized layer does Light metal pistons for diesel engines protect the surface of the piston on the combustion chamber against thermal fatigue.
  • a copper layer applied electrochemically to a light metal piston shows comparatively less damage from knocking combustion than the uncoated piston, but detaches from the piston crown after a short period of operation due to insufficient adhesive strength.
  • MTZ Motortechnische Zeitschrift
  • FIG. 2 shows a front view and a partial longitudinal section
  • FIG. 3 shows a top view of the piston crown 1 of the light metal piston 2, the top land 3 and piston crown 1 of which are covered with an electrochemically deposited iron layer 4 20 ⁇ m thick.
  • the surface area covered by the iron layer is identified by cross-hatching in the top view.
  • FIG. 5 shows a section of the piston head 12 of the longitudinal section through a light metal piston, of which a sectional plan view of the piston crown 13 is shown in FIG. 6.
  • the piston crown 13 provided with a depression 14 is reinforced with an iron layer 16 only in its edge region and the top land 15 only in its piston crown-side region.

Abstract

In a light metal piston for internal combustion engines, the surfaces exposed to combustion are provided with reinforcement. In order to avoid material damage due to knocking combustion, the surfaces exposed to combustion are reinforced with a 5 - 30 um thick electrochemically deposited iron layer. <IMAGE>

Description

Die Erfindung betrifft einen Leichtmetallkolben für Verbrennungsmotoren, insbesondere für Otto-Motoren, dessen der Verbrennung ausgesetzten Oberfläche, wenigstens jedoch Kolbenboden und/oder Feuersteg, ganz oder teilweise mit einer Bewehrung versehen sind.The invention relates to a light metal piston for internal combustion engines, in particular for Otto engines, the surface of which is exposed to combustion, but at least the piston crown and / or top land, are provided in whole or in part with reinforcement.

Steigende Kraftstoffkosten und die gesetzliche Vorschriften, insbesondere hinsichtlich der Abgaszusammensetzung, haben dazu geführt, daß Verbrennungsmotoren bezüglich des Kraftstoffverbrauchs optimal ausgelegt werden, indem unter anderem auch das Verdichtungsverhältnis vergrößert wird, um eine größere Leistung aus Hubraum und Kraftstoffverbrauch und eine unschädliche Zusammensetzung der Abgase zu erzielen. Das hat jedoch zur Folge, daß der Verbrennungsmotor auf Dauer und auch im oberen Bereich seines Last-Drehzahl-Kennfeldes einer das Klopfen erzeugenden Verbrennung unterliegt. Darunter leiden vorzugsweise alle den Brennraum begrenzenden Bauteile des Verbrennungsmotors, insbesondere aber der Leichtmetallkolben, der schon nach relativ kurzer Dauer zerstört wird, indem es, insbesondere in diskreten Bereichen, deren Lage beispeilsweise von der Brennraumform abhängt, am Kolbenboden und/oder Feuersteg zu kraterähnlichen Materialzerstörungen, wie diese beispielsweise aus der in Figur 1 der Zeichnungen wiedergegebenen fotographischen Aufnahme des Feuerstegs eines Leichtmetallkolbens zu erkennen sind, kommt. Diese Materialzerstörungen sind eindeutig auf eine klopfende Verbrennung zurückzuführen. Das Klopfen im Ottomotor entsteht dadurch, daß im Endgas - das ist der noch nicht von der Verbrennung erfaßte Gemischanteil - bedingt durch die Druck- und Temperatursteigerung infolge der Verdichtungsbewegung des Kolbens und die in einem Teil der Ladung bereits abgelaufene Verbrennung thermodynamische und chemische Bedingungen erzeugt werden, die zu einer schlagartigen Freisetzung der im Endgas enthaltenen Energie führen. Dabei werden auf die Brennraumwandungen wirkende typische Druckschwingungen hoher Frequenz gemessen, die dem normalen Druckverlauf überlagert sind. Auch die an den Brennraumoberflächen meßbaren Temperaturschwingungen sind bei klopfender Verbrennung örtlich während des Arbeitsspiels deutlich höher, ohne daß eine Erhöhung z.B. der mittleren Kolbenbodentemperatur festgestellt werden kann, die erkennbar die dem geänderten zeitlichem Verlauf der Durchbrennfunktion entsprechende Temperaturerhöhung übersteigt.Rising fuel costs and the legal regulations, in particular with regard to the exhaust gas composition, have led to internal combustion engines being optimally designed with regard to fuel consumption by, among other things, increasing the compression ratio in order to achieve greater performance from displacement and fuel consumption and a harmless composition of the exhaust gases . However, this has the consequence that the internal combustion engine is subject to knocking combustion in the long term and also in the upper region of its load-speed characteristic map. This preferably affects all components of the internal combustion engine that delimit the combustion chamber, but especially the light metal piston, which is destroyed after a relatively short period of time, particularly in discrete areas, the location of which depends, for example, on the shape of the combustion chamber, on the piston crown and / or top land to material crater-like destruction , as this example from the in Figure 1 of the drawings reproduced photographic recording of the top land of L are eichtmetallkolbens be seen coming. This material destruction is clearly due to a knocking combustion. The knock in the gasoline engine is caused by the fact that thermodynamic and chemical conditions are generated in the tail gas - that is the proportion of the mixture not yet recorded by the combustion - due to the pressure and temperature increase due to the compression movement of the piston and the combustion that has already occurred in part of the charge , which lead to a sudden release of the energy contained in the tail gas. Typical pressure vibrations of high frequency acting on the walls of the combustion chamber are measured, which are superimposed on the normal pressure curve. The temperature vibrations that can be measured on the combustion chamber surfaces are significantly higher during knocking combustion during the working cycle, without an increase, for example, in the mean piston crown temperature, which can be seen to exceed the temperature increase corresponding to the changed course of the burn-through function over time.

Es ist die Aufgabe der vorliegenden Erfindung, die einer klopfenden Verbrennung ausgesetzten Bereiche der Oberfläche eines Leichtmetallkolbens so zu gestalten, daß die durch eine klopfende Verbrennung eintretenden Schäden am Kolben vermieden werden.It is the object of the present invention to design the areas of the surface of a light metal piston which are subject to knocking combustion in such a way that the damage to the piston which occurs as a result of knocking combustion is avoided.

Die Lösung dieser Aufgabe erfolgt in der Weise, daß die der Verbrennung ausgesetzten Oberflächen des Kolbens, wenigstens jedoch Kolbenboden und/oder der Feuersteg, ganz oder teilweise erfindungsgemäß mit einer 5 bis 30 um dicken elektrochemisch abgeschiedenen Eisenschicht bewehrt sind.This object is achieved in such a way that the surfaces of the piston exposed to combustion, but at least the piston crown and / or the top land, are completely or partially reinforced according to the invention with a 5 to 30 μm thick electrochemically deposited iron layer.

Im Rahmen der Ausgestaltung der Erfindung kann die Eisenschichtt ganz oder teilweise durch eine Nickelschicht ersetzt sein.Within the scope of the embodiment of the invention, the iron layer t can be replaced entirely or partially by a nickel layer.

Die Eisenschicht übt in erster Linie eine Abschirmwirkung aus, indem vor allem die hochfrequenten Temperaturschwingungen sowie korrosive Beanspruchungskomponenten vom Leichtmetall des Kolbenkörpers ferngehalten werden. Wesentlich ist aber auch, daß die Eisenschicht selbst aufgrund ihrer hohen Festigkeit ihres homogenen Aufbaus, der glatten Oberfläche und durch die hohe Haftfestigkeit auf dem Leichtmetall den durch klopfende Verbrennung hervorgerufenen Beanspruchungen standhält. Die Gesamtheit dieser Eigenschaften läßt sich mit anderen Beschichtungen nicht erreichen, so kann beispielsweise eine durch anodische Oxidation auf dem Kolbenboden erzeugte Harteloxalschicht vergleichbarer Dicke (DE-PS 25 07 899), die durch klopfende Verbrennung eintretende Beschädigung des Leichtmetallkolbens nicht verhindern, obwohl die Harteloxalschicht bei Leichtmetallkolben für Dieselmotoren einen Schutz der brennraumseitigen Oberfläche des Kolbens gegenüber thermischen Ermüdungenserscheinungen bewirkt. Eine auf elektrochemischem Wege auf ein Leichtmetallkolben aufgebrachte Kupferschicht zeigt eine vergleichsweise geringere Beschädigung durch klopfende Verbrennung als der unbeschichtete Kolben, löst sich jedoch nach kurzer Betriebszeit infolge nicht ausreichender Haftfestigkeit vom Kolbenboden ab. Aus MTZ (Motortechnische Zeitschrift) Nr. 2/1974, Seiten 3-11 ist es bekannt, auf einen Leichtmetallkolben eine Eisenschicht elektrochemisch abzuscheiden. Dieser Kolben wird in unbewehrten Aluminiumzylinder eingesetzt. Die Eisenschicht ist dabei auf dem Kolbenschaft aufgebracht, die die Aufgabe hat, bei extremen Laufbedingungen unter allen Umständen eine Kontakt zwischen dem Leichtmetall des Zylinders und demjenigen des Kolbens zu vermeiden. Durch die Eisenbeschichtung des Kolbenschaftes wird der Kolbenschaftver;chleiß erheblich gesenkt und die Freßneigung zwischen Kolbenschaft und Zylinder sehr stark reduziert. Bei Leichtmetallkolben für luftgekühlte Motoren sind auch Feuersteg und Ringpartie mit einer Eisenschicht versehen, damit das Feuersteg- und Ringfeldspiel zur Erzielung geringen Ölverbrauchs und Gasdurchlasses so angelegt werden können, daß bei stark verformter Zylindern ein Anlaufen des Feuerstegs an die Zylinderwand toleriert werden kann.The iron layer primarily exerts a shielding effect, in particular by keeping the high-frequency temperature fluctuations and corrosive stress components away from the light metal of the piston body. But it is also essential that the iron layer itself withstands the stresses caused by knocking combustion due to its high strength, its homogeneous structure, the smooth surface and the high adhesive strength on the light metal. The totality of these properties cannot be achieved with other coatings, for example a hard anodized layer of comparable thickness (DE-PS 25 07 899) produced by anodic oxidation on the piston head, which cannot prevent damage to the light metal piston caused by knocking combustion, although the hard anodized layer does Light metal pistons for diesel engines protect the surface of the piston on the combustion chamber against thermal fatigue. A copper layer applied electrochemically to a light metal piston shows comparatively less damage from knocking combustion than the uncoated piston, but detaches from the piston crown after a short period of operation due to insufficient adhesive strength. From MTZ (Motortechnische Zeitschrift) No. 2/1974, pages 3-11 it is known to electrochemically deposit an iron layer on a light metal piston. This piston is used luminiumzylinder in unreinforced A. The iron layer is applied to the piston skirt, which has the task of avoiding contact between the light metal of the cylinder and that of the piston under all circumstances in extreme running conditions. By E isenbeschichtung the piston shaft K is olbenschaftver; chleiß significantly reduced and the F reßneigung greatly reduced between the piston skirt and cylinder. In light metal piston for air cooled engines and top land and R ingpartie are provided with an iron layer, so that the Feuersteg- and Ring Field game can be applied to achieve low oil consumption and gas passage so that a start-up of the top land can be tolerated at the cylinder wall at strongly deformed cylinders.

Die in den Zeichnungen dargestellte Erfindung wird nachfolgend beispielhaft erläutert.The invention shown in the drawings is explained below by way of example.

Fig. 2 zeigt eine Vorderansicht sowie einen Teillängsschnitt und Fig. 3 eine Draufsicht auf den Kolbenboden 1 des Leichtmetallkolbens 2, dessen Feuersteg 3 und Kolbenboden 1 mit einer 20 um dicken elektrochemisch abgeschiedenen Eisenschicht 4 überzogen sind. Der von der Eisenschicht bedeckte Oberflächenbereich ist in der Draufsicht durch Kreuzschraffur gekennzeichnet. F ig. 2 shows a front view and a partial longitudinal section, and FIG. 3 shows a top view of the piston crown 1 of the light metal piston 2, the top land 3 and piston crown 1 of which are covered with an electrochemically deposited iron layer 4 20 μm thick. The surface area covered by the iron layer is identified by cross-hatching in the top view.

Bei dem in Fig. 4 dargestellten Ausschnitt des Kolbenkopfes 5 des Längsschnitts durch einen Leichtmetallkolben sind der Kolbenboden 6, der Feuersteg 7, die kolbenbodenseitige Flanke 8 der ersten Ringnute 9 sowie der Ringnutengrund 10 mit einer Eisenschicht 11 überzogen.In the section of the piston head 5 of the longitudinal section through a light metal piston shown in FIG. 4, the piston crown 6, the top land 7, the flank 8 on the piston crown side of the first annular groove 9 and the annular groove base 10 are coated with an iron layer 11.

Die Fig. 5 zeigt einen Ausschnitt des Kolbenkopfes 12 des Längsschnitts durch einen Leichtmetallkolben von dem in Fig. 6 eine ausschnittsweise Draufsicht auf den Kolbenboden 13 dargestellt ist. Der mit einer Mulde 14 versehene Kolbenboden 13 ist nur in seinem Randbereich und der Feuersteg 15 nur in seinem kolbenbodenseitigen Bereich mit einer Eisenschicht 16 bewehrt.FIG. 5 shows a section of the piston head 12 of the longitudinal section through a light metal piston, of which a sectional plan view of the piston crown 13 is shown in FIG. 6. The piston crown 13 provided with a depression 14 is reinforced with an iron layer 16 only in its edge region and the top land 15 only in its piston crown-side region.

Bei dem in Fig. 7 wiedergegebenen Längsschnitt entlang der Schnittlinie I-I der Fig. 8, die eine Draufsicht auf den Kolbenboden 18 durch den Kopf 17 eines Leichtmetallkolbens zeigt, ist die auf den Kolbenboden 19 und den Feuersteg 19 abgeschiedene Eisenschicht 20 durch nachträgliches Anbringen der Mulde 21 und der Ventiltaschen 22, 23 abgetragen.In the model shown in Fig. 7 longitudinal section along section line II of FIG. 8, by the head 17 is a plan view of the piston head 18 of a light metal piston, on the piston head 19 and the top land 19 deposited E isenschicht 20 by subsequent attachment of the Well 21 and the valve pockets 22, 23 removed.

In einem Versuchsverbrennungsmotor, der reproduzierbar mit klopfender Verbrennung gefahren wurde, wurden mit einer Eisenschicht am Kolbenboden und Feuersteg versehene 7 Leichtmetallkolben in einem Satz zusammen mit unbeschichteten Leichtmetallkolben über mehr als 60 Stunden erprobt. Während die unbeschichteten Leichtmetallkolben nach jeweils etwa 12 Stunden Laufdauer erhebliche Materialzerstörungen am Kolbenboden aufwiesen und ausgewechselt werden mußten, konnte an den mit einer Eisenschicht am Kolbenboden versehenen Leichtmetallkolben keinerlei Veränderungen festgestellt werden.In an attempt combustion engine that has been reproducibly driven with knocking combustion, were eichtmetallkolben in a set together with uncoated aluminum pistons over more than 60 hours of testing with an iron layer on the piston crown and top land provided 7 L. While the uncoated light metal pistons showed considerable material damage on the piston crown after every 12 hours of operation and had to be replaced, no changes were found in the light metal pistons with an iron layer on the piston crown.

Claims (2)

1. Leichtmetallkolben für Verbrennungsmotoren, insbesondere für Otto-Motoren, deren brennraumseitigen der Verbrennung ausgesetzten Oberflächen, wenigstens jedoch Kolbenboden (1, 6, 13, 18) und/oder Feuersteg (3, 7, 15, 19), ganz oder teilweise mit einer Bewehrung versehen sind, dadurch gekennzeichnet, daß die Bewehrung aus einer 5 bis 30 um dicken elektrochemisch abgeschiedenen Eisenschicht (4, 11, 16, 20) besteht.1. Light metal pistons for internal combustion engines, in particular for Otto engines, the combustion chamber-side surfaces exposed to the combustion, but at least the piston crown (1, 6, 13, 18) and / or top land (3, 7, 15, 19), in whole or in part with a Reinforcement are provided, characterized in that the reinforcement consists of an electrochemically deposited iron layer (4, 11, 16, 20) 5 to 30 µm thick. 2. Leichtmetallkolben nach Anspruch 1, dadurch gekenzeichnet, daß die Eisenschicht ganz oder teilweise durch eine Nickelschicht ersetzbar ist.2. Light metal piston according to claim 1, characterized in that the iron layer can be replaced in whole or in part by a nickel layer.
EP83200003A 1982-01-20 1983-01-04 Light-metal piston Expired - Lifetime EP0084385B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3201498 1982-01-20
DE19823201498 DE3201498A1 (en) 1982-01-20 1982-01-20 LIGHT METAL PISTON

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EP0084385A1 true EP0084385A1 (en) 1983-07-27
EP0084385B1 EP0084385B1 (en) 1990-11-07

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EP83200003A Expired - Lifetime EP0084385B1 (en) 1982-01-20 1983-01-04 Light-metal piston

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0172002A2 (en) * 1984-08-13 1986-02-19 Ae Plc The treatment of pistons
GB2205923A (en) * 1987-06-18 1988-12-21 Ae Plc Pistons
EP1464821A1 (en) * 2003-04-03 2004-10-06 Federal-Mogul Nürnberg GmbH Piston for an internal combustion engine and method for producing the piston
JP2014020300A (en) * 2012-07-19 2014-02-03 Mazda Motor Corp Heat insulation structure for engine combustion chamber

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3304320C1 (en) * 1983-02-09 1988-07-07 M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8900 Augsburg Light alloy piston for internal combustion engines, especially those operated using heavy oil

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB492345A (en) * 1936-07-03 1938-09-19 Aluminum Colors Inc Improvements in or relating to pistons
CH227662A (en) * 1938-05-03 1943-06-30 Berghaus Bernhard Light metal pistons provided with a metal protective layer for internal combustion engines, as well as a method and device for the production of metal protective layers on light metal pistons.
DE2743512A1 (en) * 1977-08-27 1979-03-01 Eugen Stump IC engine piston suppressing noise - has chromium plated rim ring held with heat resistant expansion layer

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1426138A (en) * 1919-01-09 1922-08-15 Aluminum Manufactures Inc Piston
FR600601A (en) * 1925-06-26 1926-02-11 Ets De Dion Bouton New piston for internal combustion engine
GB510404A (en) * 1938-05-03 1939-08-01 Bernhard Berghaus Improvements in and relating to light metal pistons and coatings therefor
DE2921952A1 (en) * 1979-05-30 1980-12-04 Volkswagenwerk Ag Light alloy piston for IC engine - has hard wearing surface layer of aluminium oxide deposited electrolytically

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB492345A (en) * 1936-07-03 1938-09-19 Aluminum Colors Inc Improvements in or relating to pistons
CH227662A (en) * 1938-05-03 1943-06-30 Berghaus Bernhard Light metal pistons provided with a metal protective layer for internal combustion engines, as well as a method and device for the production of metal protective layers on light metal pistons.
DE2743512A1 (en) * 1977-08-27 1979-03-01 Eugen Stump IC engine piston suppressing noise - has chromium plated rim ring held with heat resistant expansion layer

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
MTZ MOTORTECHNISCHE ZEITSCHRIFT, Band 35, Nr. 2, Februar 1974, Seiten 33-41, 36-37 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0172002A2 (en) * 1984-08-13 1986-02-19 Ae Plc The treatment of pistons
EP0172002A3 (en) * 1984-08-13 1986-12-30 Ae Plc The treatment of pistons
US4664021A (en) * 1984-08-13 1987-05-12 Ae Plc Treatment of pistons
GB2205923A (en) * 1987-06-18 1988-12-21 Ae Plc Pistons
US4939984A (en) * 1987-06-18 1990-07-10 Ae Plc Investment-cast piston crown cap with encapsulated non-metallic insulating core
EP1464821A1 (en) * 2003-04-03 2004-10-06 Federal-Mogul Nürnberg GmbH Piston for an internal combustion engine and method for producing the piston
JP2014020300A (en) * 2012-07-19 2014-02-03 Mazda Motor Corp Heat insulation structure for engine combustion chamber

Also Published As

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DE3381978D1 (en) 1990-12-13
EP0084385B1 (en) 1990-11-07
DE3201498A1 (en) 1983-07-28

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