EP1231374B1 - Piston for an internal combustion engine - Google Patents

Piston for an internal combustion engine Download PDF

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Publication number
EP1231374B1
EP1231374B1 EP01130054A EP01130054A EP1231374B1 EP 1231374 B1 EP1231374 B1 EP 1231374B1 EP 01130054 A EP01130054 A EP 01130054A EP 01130054 A EP01130054 A EP 01130054A EP 1231374 B1 EP1231374 B1 EP 1231374B1
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EP
European Patent Office
Prior art keywords
piston
oil
region
head
closed passage
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.)
Expired - Lifetime
Application number
EP01130054A
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German (de)
French (fr)
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EP1231374A3 (en
EP1231374A2 (en
Inventor
Wolfram Krausse
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Bayerische Motoren Werke AG
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Bayerische Motoren Werke AG
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Publication of EP1231374A2 publication Critical patent/EP1231374A2/en
Publication of EP1231374A3 publication Critical patent/EP1231374A3/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 
    • F02F3/16—Pistons  having cooling means
    • F02F3/20—Pistons  having cooling means the means being a fluid flowing through or along piston
    • F02F3/22—Pistons  having cooling means the means being a fluid flowing through or along piston the fluid being liquid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P3/00—Liquid cooling
    • F01P3/06—Arrangements for cooling pistons
    • F01P3/08—Cooling of piston exterior only, e.g. by jets
    • 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
    • F02F2200/00—Manufacturing
    • F02F2200/04—Forging of engine parts
    • 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
    • F02F2200/00—Manufacturing
    • F02F2200/06—Casting

Definitions

  • the invention relates to a piston, in particular for an internal combustion engine having a piston head, a piston skirt which comprises piston pin bosses and is each set back in the region of these piston pin bosses such that a segment section of the piston head projects over the recessed piston skirt region.
  • Such a piston is out DE 197 47 746 C1 known.
  • an oil injection opening is formed in the region of the piston head which projects over the piston skirt.
  • the introduction of the oil in this oil injection port is effected by a directed to the oil injection port radiated oil jet, which extends in a space between the piston skirt and cylinder wall.
  • the injected into the oil injection port oil flows through an annular channel which extends in the region of the piston ring grooves, and thereby passes to an outlet opening.
  • the production of this piston proves to be relatively expensive from a manufacturing point of view.
  • the invention has for its object to provide a cost-producible piston, in particular for an internal combustion engine, in which a sufficient heat dissipation is ensured at a favorable temperature profile.
  • a piston having a piston head, a piston shaft which comprises a pair of piston pin bosses and is formed in the piston pin hub recessed so that the piston head overhangs the recessed piston shaft in the region of the piston pin bosses in the radial direction, one of the piston skirt and the Piston head limited piston interior with an oil guide wall provided therein, the an oil jet impingement zone and at least one closed passageway extending from the interior of the piston so directed that the oil passes through the passageway and exits through at least one outlet opening and, after exiting the closed passageway, flows against the piston head in its region projecting beyond the piston skirt ,
  • the oil guide according to the invention proves to be particularly advantageous.
  • the oil guide wall is formed such that it merges in the region of an oil flow path in the inner wall of the passage channel.
  • the inlet region of the through-channel is preferably designed widened like a funnel and arranged in an inner corner region.
  • a particularly high mechanical strength of the piston is achieved in an advantageous manner by the passage channel is guided past the piston pin bosses. As a result, a weakening of the transition region between the hub region of the piston skirt and the piston head is avoided.
  • the through-channel preferably extends laterally bulging toward the edge of the piston area, past the piston pin bosses like a sickle.
  • a particularly effective heat transfer to the oil is preferably achieved in that the through channel underflows the piston shaft through the piston head.
  • the through channel underflows the piston shaft through the piston head.
  • the oil guide surface is advantageously formed by the inner wall of the piston skirt in cooperation with the underside of the piston head and preferably comprises a channel zone which extends from the Strahlauf Economicszone into the passageway. This makes it possible to almost completely lead the sprayed oil into the passageway.
  • At least one through-channel is provided for each of the sections of the piston head protruding radially beyond the piston skirt. This makes it possible to evenly cool the provided on both sides and formed by the piston head piston ring balconies. In a particularly advantageous manner, however, each piston pin hub associated with two through channels, the laterally bulging out towards the piston edge, the piston pin hub through the piston skirt and / or the piston head rotate through.
  • the Strahlaufeuticzone is preferably located on the thermally higher loaded piston side.
  • the jet impact zone is preferably located in the interior half of the piston skirt of the piston skirt wall which is supported on a cylinder wall during a working stroke.
  • a particularly high cooling effect is achieved according to a particular aspect of the present invention in that a second StrahlaufSullivanzone is formed in the interior of the piston skirt.
  • a second Strahlauf Economicszone is formed in the interior of the piston skirt.
  • a total of four through channels are provided, which extend directed around the piston pin bosses around to a central region of the piston ring balconies out.
  • the cross-section of the passageways is preferably at least 15% of the cross-sectional area of the piston pin bore.
  • a particularly effective heat transfer is achieved if the cross section of the passage channels is dimensioned such that it corresponds in at least the quotient of the oil stream sprayed off from an oil spray nozzle and a mean oil jet impact velocity.
  • the piston is preferably made as a cast piston.
  • the through-channel can be formed in a favorable manufacturing technology.
  • the surface of the passageway may be substantially gussrau. It is also possible to manufacture the piston by a forging process.
  • the passageway is then preferably formed in the context of a machining operation.
  • the ⁇ lstrahlauf Economicszone is preferably formed such that it causes a division of the oil jet into at least two partial streams.
  • one of the two partial flows is directed to one of the two piston head projections.
  • the piston head projection according to a particularly preferred embodiment of the invention seen from the axial direction has a substantially circular segment-like shape, wherein the passage channel is directed such that it acts on the piston head projection of an area adjacent to the segment peaks, directed towards the segment axis, with oil.
  • the oil guide, the passage and the deflection in the region of the piston head projection preferably form a ⁇ l Entrysweg with large oil contact surface.
  • the oil contact is preferably intensified by multiple deflection of the oil in particular by deflection with increasing curvature.
  • piston 1 comprises a, visible here only with respect to its underside, the piston head 2 and a piston shaft 3 integral therewith.
  • the piston skirt 3 comprises two piston pin bosses 4, 5 with aligned piston pin bores 6.
  • the piston skirt 3 is set back in the region of the piston pin bosses 4, 5 such that the piston head 2 projects outwardly beyond the piston skirt 3 in the radial direction.
  • the region of the piston head 2 projecting over the piston skirt 3, viewed from the axial direction, has a substantially circle-segment-shaped form.
  • a corresponding, in this view to the piston pin axis X largely symmetrical, circular segment is shown here sketch-like.
  • the piston skirt 3 radially overhanging region of the piston head 2 forms a piston ring balcony 7.
  • This piston ring balcony 7 comprises in its piston pin axis X facing the lower region of a cooling oil acted upon by the cooling zone. 8
  • the supply of the cooling oil to the cooling zone 8 takes place through an oil jet 9 directed into an inner region of the piston skirt 3.
  • This oil jet 9 is aligned in such a way that it strikes a jet impact zone 10 formed in the inner region of the piston skirt 3.
  • the Strahlauf Economicszone 10 is here near the edge region of the piston 1 and is formed by an inner surface portion of the piston shaft 3 and by the lower inner surface of the piston head 2.
  • a deflection and division of the oil jet into at least two partial streams 11, 12, 13 takes place.
  • the two partial streams 11, 12 are guided by inlet passages 14, 15 of passage channels 16, 17 through the inner wall of the piston 1 acting as an oil guide surface.
  • the contact between the flowing oil and the wall of the piston is maintained by the fact that the oil path is curved so that the oil is urged by thereby becoming effective radial forces against the ⁇ l Adjustswandung.
  • the passage channels 16, 17 extend crescent-shaped past the root area of the piston pin bosses 4, 5 into a heat exchange zone K (see circle segment sketch) of the piston ring balcony 7.
  • the action on the lower area of the piston ring Kolbenringbalkons 7 takes place from the region of the circular segment tips S1, S2 directed towards the piston pin axis X out.
  • a plurality of outlet openings 18, 19, 20, 21 are provided in the area of the heat exchange zone K.
  • the outlet openings 18, 19 are used for the discharge of the oil of the oil partial stream 12.
  • the outlet openings 20, 21 are used for the discharge of oil which is supplied via a further passage 22 by a second oil jet (not shown).
  • the passage 17 is guided such that it underflows the piston shaft 3 through the piston head 2 through.
  • the curvature is chosen so that the oil sweeps primarily the hotter wall zones of the passageway.
  • the oil supplied via the passage channels 17, 22 is deflected in such a way that it is radiated substantially parallel to the piston stroke axis or to the recessed wall of the piston skirt 3. It is possible to tune the geometry of the oil-loaded zone of the piston ring balcony 7 - and thus the emission characteristic - such that a defined lubrication of the cylinder wall is achieved.
  • Fig.2 is a bottom view of a second embodiment of a piston 1 is shown. Also in this embodiment, the piston shaft 3 is formed in the region of the piston pin bosses 4, 5 to form piston ring balconies 7, reset.
  • the inlet openings 14, 15 are placed in a corner region which is defined by the inner wall of the piston shaft 3, the inwardly projecting hub areas 4, 5 and the underside of the piston head 2. As a result, a funnel effect is achieved. This funnel effect is further supported in the assembled state by the upper portion of a connecting rod.
  • piston 1 corresponds in terms of the design of the piston skirt 3 and piston head 2 limited inner region, substantially the piston to Fig.2 ,
  • the remarks to Fig.2 Apart from the differences set out below, they apply mutatis mutandis.
  • the geometry of the oil path 25, in particular an outer peripheral edge 26 of the trough-like depression is set such that the supplied oil is dropped down substantially parallel to the oscillation direction of the piston. It is possible to dimension this oil path in terms of their volume so large that a dropping of the oil - at least for the most part - takes place only in a bottom dead center position of the piston.
  • the depth of the oil path 25 is about 8mm.
  • the width of the oil path measured in the radial direction of the piston is preferably in the range of 4 to 6 mm. This information refers to a piston with a diameter of approx. 80mm.
  • the length of the oil path 25 measured in the circumferential direction essentially corresponds at least to the width b of the piston pin hub 4.
  • FIG 4 a detail view of a piston inner region with a specially designed Strahlauf Economicszone 10 is shown.
  • the Strahlauf Hugheszone 10 is located in a transition region between the inner wall of the piston skirt 3 and the underside of the piston head 2.
  • the coming into contact with the oil wall sections form an oil guide surface G which is formed like a trough and merges into the inner surface of the through channels 17, 16.
  • the oil guide surface G causes not only a guide of the oil but also a heat transfer to the oil, thereby allowing cooling of the adjacent piston edge region.
  • FIG. 5 a further embodiment of the heat exchange zone K of the piston ring balcony 7 is shown.
  • an oil path 25 which bulges laterally slightly towards the edge of the piston, is also formed in this exemplary embodiment.
  • These Oil web 25 ends in a deflection zone 30 in which the incoming oil flow to the crankshaft of an internal combustion engine is deflected out.
  • the passage 17 is located in this embodiment in a, a piston pressure side 31 facing away from the piston half.
  • FIG 6 is a further embodiment of a piston with a unilaterally through a through-channel 17 'flowed underside of a piston ring balcony 7, shown.
  • the oil jet 32 is deflected over an integrally formed in the piston skirt 3 Umlenkmulde 33 on the piston pin bore 6 over.
  • the Umlenkmulde 33 is formed such that the deflected oil jet 32, substantially parallel to the cylinder wall, is radiated toward the crankshaft bearing.
  • the feeding of the oil into the through-passage 17 ' also takes place in this embodiment by means of an oil guide wall provided in the inner region of the piston skirt 3, as in the exemplary embodiments described above.
  • FIGS. 7 and 8 is a further embodiment of a piston 1 is shown with a piston shaft 3, which is formed laterally retracted in the region of the Kobenbolzennaben 4, 5.
  • the piston head 2 of the piston 1 in this case projects over the piston shaft 3 in the radial direction.
  • outwardly bulging and downwardly open oil paths 25 are formed in the area of the piston ring balconies 7 formed in this way.
  • the here strongly profiled trained, the combustion chamber facing piston head surface is shown here rotated by 90 °.
  • the supply of the radiated oil to the passage channels 16, 17 also takes place here by an oil guide wall which extends to the through channels 16, 17.
  • the oil path in the inner region of the piston skirt 3 extends in the vicinity of the piston skirt so that effective cooling of the entire Edge region of the piston head is achieved.
  • the oil path extends in a radial direction laterally bulging, sickle-like around the piston pin bosses 4, 5 around.
  • the entire downwardly facing inner surface of the piston head forms an oil guide surface extending to the passageways. Due to the piston ring near and - apart from the sections within the through channels - open oil flow results in a technically advantageous manner, a large heat exchange surface.
  • the piston according to the invention is due to its improved temperature profile and its low weight in a particularly advantageous manner for GDI engines.
  • the invention is not limited to the embodiments described above.
  • the distance of the beam impact point relative to the passageway may vary.
  • the oil spray nozzle can also be arranged on the connecting rod itself.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)

Abstract

Piston (1) comprises a piston head (2), a piston shaft (3) having a pair of piston pin hubs (4, 5) and set back in the region of the piston pin hubs so that the piston head protrudes in a radial direction over the piston shaft in the region of the piston pin hubs, an inner piston chamber defined by the piston shaft and the piston head and having an oil-guiding wall forming an oil jet impact zone (10), and at least one through channel (16, 17, 22) leading outward from the inner piston chamber so that oil flowing through the through channel flows against the piston head in its region protruding over the piston shaft. Preferred Features: The oil-guiding wall changes into the inner wall of the through channel.

Description

Die Erfindung betrifft einen Kolben, insbesondere für eine Brennkraftmaschine mit einem Kolbenkopf, einem Kolbenschaft, der Kolbenbolzennaben umfasst und im Bereich dieser Kolbenbolzennaben jeweils derart zurückgesetzt ausgebildet ist, dass ein Segmentabschnitt des Kolbenkopfes den zurückgesetzten Kolbenschaftbereich überkragt.The invention relates to a piston, in particular for an internal combustion engine having a piston head, a piston skirt which comprises piston pin bosses and is each set back in the region of these piston pin bosses such that a segment section of the piston head projects over the recessed piston skirt region.

Ein derartiger Kolben ist aus DE 197 47 746 C1 bekannt. Bei diesem Kolben ist in dem den Kolbenschaft überkragenden Bereich des Kolbenkopfes eine Öl-Einspritzöffnung ausgebildet. Die Einbringung des Öles in diese Öl-Einspritzöffnung erfolgt durch einen auf die Öl-Einspritzöffnung gerichtet abgestrahlten Ölstrahl,der sich in einem Zwischenraum zwischen Kolbenschaft und Zylinderwand erstreckt. Das in die Öl-Einspritzöffnung eingespritzte Öl durchströmt einen Ringkanal, der sich im Bereich der Kolbenringnuten erstreckt, und gelangt hierbei zu einer Austrittsöffnung. Die Herstellung dieses Kolbens erweist sich unter fertigungstechnischen Gesichtspunkten als vergleichsweise aufwendig.Such a piston is out DE 197 47 746 C1 known. In this piston, an oil injection opening is formed in the region of the piston head which projects over the piston skirt. The introduction of the oil in this oil injection port is effected by a directed to the oil injection port radiated oil jet, which extends in a space between the piston skirt and cylinder wall. The injected into the oil injection port oil flows through an annular channel which extends in the region of the piston ring grooves, and thereby passes to an outlet opening. The production of this piston proves to be relatively expensive from a manufacturing point of view.

Der Erfindung liegt die Aufgabe zugrunde, einen kostengünstig herstellbaren Kolben, insbesondere für eine Brennkraftmaschine, zu schaffen, bei welchem eine ausreichende Wärmeableitung bei einem günstigen Temperaturprofil gewährleistet ist.The invention has for its object to provide a cost-producible piston, in particular for an internal combustion engine, in which a sufficient heat dissipation is ensured at a favorable temperature profile.

Diese Aufgabe wird erfindungsgemäß gelöst durch einen Kolben mit einem Kolbenkopf, einem Kolbenschaft, der ein Paar Kolbenbolzennaben umfasst und im Bereich der Kolbenbolzennaben zurückgesetzt ausgebildet ist so dass der Kolbenkopf den zurückgesetzten Kolbenschaft im Bereich der Kolbenbolzennaben in radialer Richtung überkragt, einem von dem Kolbenschaft und dem Kolbenkopf begrenzten Kolbeninnenraum mit einer darin vorgesehenen Ölführungswandung, die eine Ölstrahlauftreffzone einschließt, und wenigstens einem geschlossenen Durchgangskanal, der von dem Kolbeninneren ausgehend derart gerichtet verläuft, dass das Öl den Durchgangskanal durchströmt und durch mindestens eine Auslassöffnung austritt, wobei es nach dem Austreten aus dem geschlossenen Durchgangskanal den Kolbenkopf in seinem den Kolbenschaft überragenden Bereich anströmt.This object is achieved by a piston having a piston head, a piston shaft which comprises a pair of piston pin bosses and is formed in the piston pin hub recessed so that the piston head overhangs the recessed piston shaft in the region of the piston pin bosses in the radial direction, one of the piston skirt and the Piston head limited piston interior with an oil guide wall provided therein, the an oil jet impingement zone and at least one closed passageway extending from the interior of the piston so directed that the oil passes through the passageway and exits through at least one outlet opening and, after exiting the closed passageway, flows against the piston head in its region projecting beyond the piston skirt ,

Dadurch wird es auf fertigtechnisch vorteilhafte Weise möglich, einen mechanisch und thermisch hochbelastbaren und vergleichsweise leichten Kolben zu schaffen, bei welchem eine zuverlässige Kühlung im Randbereich des Kolbenkopfes, insbesondere im Bereich des nachfolgend als Kolbenringbalkon bezeichneten Überstandes über den Kolbenschaft gewährleistet ist. Im Hinblick darauf, dass das den Kolbenringbalkonen zugeleitete Öl bereits unmittelbar nach dem Auftreffen auf die Strahlauftreffzone eine den Kolbenringen benachbarte Innenwandungzone des Kolbens überstreicht und zudem auch in den Durchgangskanälen kolbenringnah geführt ist, ergibt sich im Bereich des Kolbenkopfes ein vergleichmäßigtes Temperaturprofil..This makes it possible in a technically advantageous manner to provide a mechanically and thermally highly resilient and relatively lightweight piston, in which a reliable cooling in the edge region of the piston head, in particular in the region of the referred to below as the piston ring balcony supernatant over the piston skirt is ensured. In view of the fact that the oil supplied to the piston ring balconies passes over an inner wall zone of the piston immediately adjacent to the jet impact zone and is also guided in the passage channels close to the piston ring, a uniform temperature profile results in the area of the piston head.

Im Hinblick auf das verbesserte Temperaturprofil des Kolbens können höhere Verdichtungsverhältnisse zugelassen werden. Auch im Hinblick auf eine Erhöhung der Lebensdauer einer Brennkraftmaschine erweist sich die erfindungsgemäße Ölführung als besonders vorteilhaft.In view of the improved temperature profile of the piston higher compression ratios can be allowed. Also with regard to increasing the service life of an internal combustion engine, the oil guide according to the invention proves to be particularly advantageous.

Gemäß einer besonders bevorzugten Ausführungsform der Erfindung ist die Ölführungswandung derart ausgebildet, dass diese im Bereich eines Ölströmungspfades in die Innenwandung des Durchgangskanals übergeht. Hierdurch wird neben einer effektiven Einspeisung des umgelenkten Ölstrahles in den Durchgangskanal auch ein verbesserter Wärmeübergang auf das Öl erreicht. Der Eintrittsbereich des Durchgangskanals ist vorzugsweise trichterartig erweitert ausgebildet und in einem Inneneckbereich angeordnet.According to a particularly preferred embodiment of the invention, the oil guide wall is formed such that it merges in the region of an oil flow path in the inner wall of the passage channel. As a result, an improved heat transfer to the oil is achieved in addition to an effective feed of the deflected oil jet in the passage. The inlet region of the through-channel is preferably designed widened like a funnel and arranged in an inner corner region.

Eine besonders hohe mechanische Festigkeit des Kolbens wird in vorteilhafter Weise erreicht, indem der Durchgangskanal an den Kolbenbolzennaben vorbeigeführt ist. Hierdurch wird eine Schwächung des Übergangsbereiches zwischen dem Nabenbereich des Kolbenschaftes und dem Kolbenkopf vermieden.A particularly high mechanical strength of the piston is achieved in an advantageous manner by the passage channel is guided past the piston pin bosses. As a result, a weakening of the transition region between the hub region of the piston skirt and the piston head is avoided.

Der Durchgangskanal erstreckt sich hierzu vorzugsweise zum Kolbenrandbereich hin seitlich ausbauchend, sichelartig an den Kolbenbolzennaben vorbei.For this purpose, the through-channel preferably extends laterally bulging toward the edge of the piston area, past the piston pin bosses like a sickle.

Ein besonders wirkungsvoller Wärmeübergang auf das Öl wird vorzugsweise dadurch erreicht, dass der Durchgangskanal den Kolbenschaft durch den Kolbenkopf hindurch unterläuft. Hierbei kann insbesondere im Bereich der brennraumnahen Wandung des Kolbenkopfes dessen thermische Belastung wirkungsvoll vermindert werden.A particularly effective heat transfer to the oil is preferably achieved in that the through channel underflows the piston shaft through the piston head. In this case, in particular in the region of the combustion chamber-near wall of the piston head whose thermal load can be effectively reduced.

Die Ölführungsfläche wird in vorteilhafter Weise durch die Innenwandung des Kolbenschaftes im Zusammenspiel mit der Unterseite des Kolbenkopfes gebildet und umfasst vorzugsweise eine Rinnenzone, die sich von der Strahlauftreffzone in den Durchgangskanal hinein erstreckt. Hierdurch wird es möglich, das aufgespritzte Öl nahezu vollständig in den Durchgangskanal hinein zu führen.The oil guide surface is advantageously formed by the inner wall of the piston skirt in cooperation with the underside of the piston head and preferably comprises a channel zone which extends from the Strahlauftreffzone into the passageway. This makes it possible to almost completely lead the sprayed oil into the passageway.

Vorzugsweise ist für jeden der radial über den Kolbenschaft überstehenden Abschnitte des Kolbenkopfes wenigstens ein Durchgangskanal vorgesehen. Hierdurch wird es möglich, die beidseitig vorgesehenen und durch den Kolbenkopf gebildeten Kolbenringbalkone gleichmäßig zu kühlen. In besonders vorteilhafter Weise sind jedoch jeder Kolbenbolzennabe zwei Durchgangskanäle zugeordnet, die seitlich zum Kolbenrand hin ausbauchend, die Kolbenbolzennabe durch den Kolbenschaft und/oder den Kolbenkopf hindurch umlaufen.Preferably, at least one through-channel is provided for each of the sections of the piston head protruding radially beyond the piston skirt. This makes it possible to evenly cool the provided on both sides and formed by the piston head piston ring balconies. In a particularly advantageous manner, however, each piston pin hub associated with two through channels, the laterally bulging out towards the piston edge, the piston pin hub through the piston skirt and / or the piston head rotate through.

Die Strahlauftreffzone befindet sich vorzugsweise auf der thermisch höher belasteten Kolbenseite. Bei gleichmäßiger thermischer Belastung der Kolbenoberseite befindet sich die Strahlauftreffzone vorzugsweise in der Innenraumhälfte des Kolbenschaftes jener Kolbenschaftwandung die sich bei einem Arbeitshub an einer Zylinderwandung abstützt.The Strahlauftreffzone is preferably located on the thermally higher loaded piston side. With uniform thermal load on the piston top side, the jet impact zone is preferably located in the interior half of the piston skirt of the piston skirt wall which is supported on a cylinder wall during a working stroke.

Eine besonders hohe Kühlwirkung wird gemäß einem besonderen Aspekt der vorliegenden Erfindung dadurch erreicht, dass im Innenbereich des Kolbenschaftes eine zweite Strahlauftreffzone ausgebildet ist. Vorzugsweise sind hierbei insgesamt vier Durchgangskanäle vorgesehen, die sich um die Kolbenbolzennaben herum zu einem Mittenbereich der Kolbenringbalkone hin gerichtet erstrecken.A particularly high cooling effect is achieved according to a particular aspect of the present invention in that a second Strahlauftreffzone is formed in the interior of the piston skirt. Preferably, in this case a total of four through channels are provided, which extend directed around the piston pin bosses around to a central region of the piston ring balconies out.

Der Querschnitt der Durchgangskanäle beträgt vorzugsweise wenigstens 15% der Querschnittsfläche der Kolbenbolzenbohrung. Ein besonders wirkungsvoller Wärmeübergang wird erreicht, wenn der Querschnitt der Durchgangskanäle derart bemessen ist, dass dieser im wenigstens dem Quotienten aus dem seitens einer Ölspritzdüse abgespritzten Ölstrom und einer mittleren Öl-Strahlauftreffgeschwindigkeit, entspricht.The cross-section of the passageways is preferably at least 15% of the cross-sectional area of the piston pin bore. A particularly effective heat transfer is achieved if the cross section of the passage channels is dimensioned such that it corresponds in at least the quotient of the oil stream sprayed off from an oil spray nozzle and a mean oil jet impact velocity.

Der Kolben ist vorzugsweise als Gusskolben gefertigt. Hierbei kann der Durchgangskanal auf fertigungstechnisch günstige Weise ausgebildet werden. Die Oberfläche des Durchgangskanals kann im wesentlichen gussrau sein. Es ist auch möglich, den Kolben durch einen Schmiedevorgang zu fertigen. Der Durchgangskanal wird dann vorzugsweise im Rahmen einer spanabhebenden Nachbearbeitung ausgebildet.The piston is preferably made as a cast piston. In this case, the through-channel can be formed in a favorable manufacturing technology. The surface of the passageway may be substantially gussrau. It is also possible to manufacture the piston by a forging process. The passageway is then preferably formed in the context of a machining operation.

Die Ölstrahlauftreffzone ist vorzugsweise derart ausgebildet, dass diese eine Aufteilung des Ölstrahles in wenigstens zwei Teilströme bewirkt. Vorzugsweise wird jeweils einer der beiden Teilströme zu einem der beiden Kolbenkopfüberstände geleitet.The Ölstrahlauftreffzone is preferably formed such that it causes a division of the oil jet into at least two partial streams. Preferably, in each case one of the two partial flows is directed to one of the two piston head projections.

Der Kolbenkopfüberstand weist gemäß einer besonders bevorzugten Ausführungsform der Erfindung aus axialer Richtung gesehen eine im wesentlichen kreissegmentartige Gestalt auf, wobei der Durchgangskanal derart gerichtet verläuft, dass dieser den Kolbenkopfüberstand aus einem den Segmentspitzen benachbarten Bereich, zur Segmentachse hin gerichtet, mit Öl beaufschlagt.The piston head projection, according to a particularly preferred embodiment of the invention seen from the axial direction has a substantially circular segment-like shape, wherein the passage channel is directed such that it acts on the piston head projection of an area adjacent to the segment peaks, directed towards the segment axis, with oil.

Die Ölführungswandung, der Durchgangskanal und die Umlenkzone im Bereich des Kolbenkopfüberstandes, bilden vorzugsweise einen Ölführungsweg mit großer Ölkontaktfläche. Der Ölkontakt wird vorzugsweise durch mehrfache Umlenkung des Öles insbesondere durch Umlenkzonen mit zunehmender Krümmung intensiviert.The oil guide, the passage and the deflection in the region of the piston head projection, preferably form a Ölführungsweg with large oil contact surface. The oil contact is preferably intensified by multiple deflection of the oil in particular by deflection with increasing curvature.

Weitere vorteilhafte Einzelheiten der Erfindung ergeben sich aus der nachfolgenden Beschreibung, in Verbindung mit der Zeichnung. Es zeigt:

Fig. 1
eine perspektivische Ansicht des Innenbereiches eines Kolbens gemäß einer ersten Ausführungsform der Erfindung mit angedeutetem Ölführungsweg;
Fig.2
eine perspektivische Ansicht eines Kolbens gemäß einem zweiten Ausführungsbeispiel - ebenfalls von unten;
Fig.3
eine perspektivische Ansicht eines Kolbens gemäß einer dritten Ausführungsform der Erfindung von unten, mit einem wannenartig ausgebildeten Ölauslassbereich;
Fig.4
eine perspektivische Detailansicht der Ölstrahlauftreffzone gemäß einer vierten Ausführungsform der Erfindung mit einer rinnenartig gewölbten und bogenförmig zum Kolbenrand ausbauchenden, zu den Durchgangskanälen führenden Ölführungswandung;
Fig.5
eine perspektivische Ansicht des Kolbenbolzen-Nabenbereiches des Kolbenschaftes von außen gemäß einer fünften Ausführungsform der Erfindung;
Fig.6
eine perspektivische Ansicht des Kolbenringbalkons einer sechsten Ausführungsform eines erfindungsgemäßen Kolbens;
Fig.7
eine Axialschnittansicht einer siebten Ausführungsform eines erfindungsgemäßen Kolbens mit angedeutetem, schräg in den Kolbeninnenbereich gerichtetem, Ölstrahl;
Fig. 8
eine Radialschnittansicht des Kolbens nach Fig.7 auf Höhe der Kolbenbolzenachse;
Further advantageous details of the invention will become apparent from the following description, taken in conjunction with the drawings. It shows:
Fig. 1
a perspective view of the interior of a piston according to a first embodiment of the invention with indicated Ölführungsweg;
Fig.2
a perspective view of a piston according to a second embodiment - also from below;
Figure 3
a perspective view of a piston according to a third embodiment of the invention from below, with a trough-shaped Ölauslassbereich;
Figure 4
a detailed perspective view of Ölstrahlauftreffzone according to a fourth embodiment of the invention with a trough-like curved and arcuate flared to the piston edge, leading to the passage channels oil guide wall;
Figure 5
a perspective view of the piston pin hub portion of the piston skirt from the outside according to a fifth embodiment of the invention;
Figure 6
a perspective view of the piston ring balcony of a sixth embodiment of a piston according to the invention;
Figure 7
an axial sectional view of a seventh embodiment of a piston according to the invention with indicated, directed obliquely into the piston inner region, oil jet;
Fig. 8
a radial sectional view of the piston after Figure 7 at the height of the piston pin axis;

Der in Fig.1 abschnittsweise von unten dargestellte Kolben 1 umfasst einen, hier nur hinsichtlich seiner Unterseite sichtbaren, Kolbenkopf 2 und einen hiermit integral ausgebildeten Kolbenschaft 3.The in Fig.1 Sectionally from below shown piston 1 comprises a, visible here only with respect to its underside, the piston head 2 and a piston shaft 3 integral therewith.

Der Kolbenschaft 3 umfasst zwei Kolbenbolzennaben 4, 5 mit fluchtenden Kolbenbolzenbohrungen 6. Der Kolbenschaft 3 ist im Bereich der Kolbenbolzennaben 4, 5 derart zurückgesetzt ausgebildet, dass der Kolbenkopf 2 den Kolbenschaft 3 in radialer Richtung nach außen überkragt. Der den Kolbenschaft 3 überkragende Bereich des Kolbenkopfes 2 hat, aus axialer Richtung gesehen, eine im wesentlichen kreissegmentförmige Gestalt. Ein entsprechendes, in dieser Ansicht zur Kolbenbolzenachse X weitgehend symmetrisches, Kreissegment ist hier skizzenartig dargestellt.The piston skirt 3 comprises two piston pin bosses 4, 5 with aligned piston pin bores 6. The piston skirt 3 is set back in the region of the piston pin bosses 4, 5 such that the piston head 2 projects outwardly beyond the piston skirt 3 in the radial direction. The region of the piston head 2 projecting over the piston skirt 3, viewed from the axial direction, has a substantially circle-segment-shaped form. A corresponding, in this view to the piston pin axis X largely symmetrical, circular segment is shown here sketch-like.

Der den Kolbenschaft 3 radial überkragende Bereich des Kolbenkopfes 2 bildet einen Kolbenringbalkon 7. Dieser Kolbenringbalkon 7 umfasst in seinem der Kolbenbolzenachse X zugewandten, unteren Bereich eine von Kühlöl beaufschlagte Kühlzone 8.The piston skirt 3 radially overhanging region of the piston head 2 forms a piston ring balcony 7. This piston ring balcony 7 comprises in its piston pin axis X facing the lower region of a cooling oil acted upon by the cooling zone. 8

Die Zuleitung des Kühlöles zu der Kühlzone 8 erfolgt durch einen, in einen Innenbereich des Kolbenschaftes 3 gerichteten Ölstrahl 9. Dieser Ölstrahl 9 ist derart ausgerichtet, dass dieser auf eine im Innenbereich des Kolbenschaftes 3 gebildete Strahlauftreffzone 10 trifft.The supply of the cooling oil to the cooling zone 8 takes place through an oil jet 9 directed into an inner region of the piston skirt 3. This oil jet 9 is aligned in such a way that it strikes a jet impact zone 10 formed in the inner region of the piston skirt 3.

Die Strahlauftreffzone 10 befindet sich hier nahe dem Randbereich des Kolbens 1 und ist durch einen Innenflächenabschnitt des Kolbenschaftes 3 sowie durch die untere Innenfläche des Kolbenkopfes 2 gebildet. Im Bereich der Strahlauftreffzone 10 erfolgt eine Umlenkung und Aufteilung des Ölstrahles in wenigstens zwei Teilströme 11, 12, 13. Die beiden Teilströme 11, 12 werden durch die als Ölführungsfläche wirkende Innenwandung des Kolbens 1 zu Eintrittsöffnungen 14, 15 von Durchgangskanälen 16, 17 geführt. Der Kontakt zwischen dem fließenden Öl und der Wandung des Kolbens wird dadurch aufrecht erhalten, dass die Ölbahn derart gekrümmt verläuft, dass das Öl durch hierbei wirksam werdende Radialkräfte gegen die Ölführungswandung gedrängt wird.The Strahlauftreffzone 10 is here near the edge region of the piston 1 and is formed by an inner surface portion of the piston shaft 3 and by the lower inner surface of the piston head 2. In the region of the jet impact zone 10, a deflection and division of the oil jet into at least two partial streams 11, 12, 13 takes place. The two partial streams 11, 12 are guided by inlet passages 14, 15 of passage channels 16, 17 through the inner wall of the piston 1 acting as an oil guide surface. The contact between the flowing oil and the wall of the piston is maintained by the fact that the oil path is curved so that the oil is urged by thereby becoming effective radial forces against the Ölführungswandung.

Die Durchgangskanäle 16, 17 erstrecken sich sichelförmig am Wurzelbereich der Kolbenbolzennaben 4, 5 vorbei in eine Wärmetauschzone K (siehe Kreissegmentskizze) des Kolbenringbalkons 7. Die Beaufschlagung des unteren Bereiches des Kolbenringbalkons 7 erfolgt aus dem Bereich der Kreissegmentspitzen S1, S2 zur Kolbenbolzenachse X hin gerichtet.The passage channels 16, 17 extend crescent-shaped past the root area of the piston pin bosses 4, 5 into a heat exchange zone K (see circle segment sketch) of the piston ring balcony 7. The action on the lower area of the piston ring Kolbenringbalkons 7 takes place from the region of the circular segment tips S1, S2 directed towards the piston pin axis X out.

Im Bereich der Wärmetauschzone K sind mehrere Auslassöffnungen 18, 19, 20, 21 vorgesehen. Durch zwischen den Auslassöffnungen 18, 19, 20, 21 gebildete Stege wird die zum Wärmetausch zur Verfügung stehende Fläche vergrößert. Die Auslassöffnungen 18, 19 dienen der Ableitung des Öls des Ölteilstromes 12. Die Auslassöffnungen 20, 21 dienen der Ableitung von Öl das über einen weiteren Durchgangskanal 22 von einem zweiten Ölstrahl (nicht dargestellt) zugeleitet wird.In the area of the heat exchange zone K, a plurality of outlet openings 18, 19, 20, 21 are provided. By between the outlet openings 18, 19, 20, 21 formed webs, the area available for heat exchange surface is increased. The outlet openings 18, 19 are used for the discharge of the oil of the oil partial stream 12. The outlet openings 20, 21 are used for the discharge of oil which is supplied via a further passage 22 by a second oil jet (not shown).

Der Durchgangskanal 17 ist derart geführt, dass dieser den Kolbenschaft 3 durch den Kolbenkopf 2 hindurch unterläuft. Der Krümmungsverlauf ist derart gewählt, dass das Öl primär die heißeren Wandungszonen des Durchgangskanals überstreicht.The passage 17 is guided such that it underflows the piston shaft 3 through the piston head 2 through. The curvature is chosen so that the oil sweeps primarily the hotter wall zones of the passageway.

Im Bereich des Kolbenringbalkons 7 wird das über die Durchgangskanäle 17, 22 zugeführte Öl derart abgelenkt, dass dieses im wesentlichen parallel zur Kolbenhubachse oder zur zurückgesetzten Wandung des Kolbenschaftes 3 hin abgestrahlt wird. Es ist möglich, die Geometrie der ölbeaufschlagten Zone des Kolbenringbalkons 7 - und damit die Abstrahlcharakteristik - derart abzustimmen, dass eine definierte Schmierung der Zylinderwandung erreicht wird.In the area of the piston ring balcony 7, the oil supplied via the passage channels 17, 22 is deflected in such a way that it is radiated substantially parallel to the piston stroke axis or to the recessed wall of the piston skirt 3. It is possible to tune the geometry of the oil-loaded zone of the piston ring balcony 7 - and thus the emission characteristic - such that a defined lubrication of the cylinder wall is achieved.

In Fig.2 ist eine Unteransicht einer zweiten Ausführungsform eines Kolbens 1 dargestellt. Auch bei dieser Ausführungsform ist der Kolbenschaft 3 im Bereich der Kolbenbolzennaben 4, 5 unter Bildung von Kolbenringbalkonen 7, zurückgesetzt ausgebildet.In Fig.2 is a bottom view of a second embodiment of a piston 1 is shown. Also in this embodiment, the piston shaft 3 is formed in the region of the piston pin bosses 4, 5 to form piston ring balconies 7, reset.

In dem gemeinsam von Kolbenschaft 3 und Kolbenkopf 2 begrenzten Kolbeninnenraum sind im Übergangsbereich zwischen Kolbenschaft 3 und Kolbenkopf 2 zwei Strahlauftreffzonen 12, 24 ausgebildet. Durch diese Strahlauftreffzonen 12, 24, werden die paarweise in den Kolbeninnenbereich gerichteten Ölstrahlen 9, 9' aufgeteilt und als entsprechende Teilströme zu den Durchgangskanälen 17, 16, 22, 22' geführt. Die Durchgangskanäle 17, 16, 22, 22' umlaufen auch bei diesem Ausführungsbeispiel den jeweiligen Nabenbereich des Kolbenschaftes 3 sichelartig und in seitlich ausbauchender Weise.In the piston internal space bounded by piston skirt 3 and piston head 2, two beam impact zones 12, 24 are formed in the transition region between piston skirt 3 and piston head 2. Through these Strahlauftreffzonen 12, 24, the pairwise directed into the piston inner region oil jets 9, 9 'split and as corresponding partial flows to the through channels 17, 16, 22, 22' out. The through-channels 17, 16, 22, 22 'also circulate in this Embodiment, the respective hub portion of the piston shaft 3 sickle-like and laterally bulging manner.

Auf der Unterseite des kreissegmentförmigen Kolbenringbalkons 7 befindet sich die Wärmetauschzone K. Die Wärmetauschzone K umfasst drei Auslassöffnungen 18, 19' und 21. Die Auslassöffnungen 18, 19' und 21 weisen einen im wesentlichen kreisförmigen Querschnitt auf und kommunizieren mit beiden benachbarten Durchgangskanälen 17, 22 so dass insbesondere über die mittlere Auslassöffnung 19' Öl austreten kann das über den Durchgangskanal 17 oder den Durchgangskanal 22 zugeführt wird. Der Verlauf der Durchgangskanäle 17, 22 ist durch Strichlinien angedeutet. Durch den hier getroffenen bogenförmigen und in den Kolbenkopf 2 eindringenden Verlauf der Durchgangskanäle 17, 22 wird neben einer Kühlung der Kolbenringbalkone 7 auch eine Wärmeableitung aus den angrenzenden Kolbenringzonen erreicht.The heat exchange zone K comprises three outlet openings 18, 19 'and 21. The outlet openings 18, 19' and 21 have a substantially circular cross-section and communicate with both adjacent passageways 17, 22nd so that in particular can escape via the central outlet opening 19 'oil which is supplied via the passageway 17 or the passageway 22. The course of the passageways 17, 22 is indicated by dashed lines. By virtue of the arcuate course of the passage channels 17, 22 penetrating into the piston head 2, a heat dissipation from the adjacent piston ring zones is achieved in addition to cooling of the piston ring balconies 7.

Die Eintrittsöffnungen 14, 15 sind in einem Eckbereich plaziert der durch die Innenwandung des Kolbenschaftes 3, dessen nach innen vordringende Nabenbereiche 4, 5 und die Unterseite des Kolbenkopfes 2 definiert ist. Hierdurch wird eine Trichterwirkung erreicht. Diese Trichterwirkung wird im montierten Zustand durch den oberen Bereich eines Pleuels noch weiter unterstützt.The inlet openings 14, 15 are placed in a corner region which is defined by the inner wall of the piston shaft 3, the inwardly projecting hub areas 4, 5 and the underside of the piston head 2. As a result, a funnel effect is achieved. This funnel effect is further supported in the assembled state by the upper portion of a connecting rod.

Der in Fig.3 ebenfalls von unten abschnittsweise dargestellte Kolben 1 entspricht hinsichtlich der Gestaltung des von Kolbenschaft 3 und Kolbenkopf 2 begrenzten Innenbereiches, im wesentlichen dem Kolben nach Fig.2. Die Ausführungen zu Fig.2 gelten, von den nachfolgend dargelegten Unterschieden abgesehen, sinngemäß.The in Figure 3 also from below shown in sections piston 1 corresponds in terms of the design of the piston skirt 3 and piston head 2 limited inner region, substantially the piston to Fig.2 , The remarks to Fig.2 Apart from the differences set out below, they apply mutatis mutandis.

Bei dem Kolben gem. Fig.3 ist im Bereich des Kolbenringbalkons 7 eine muldenartig vertiefte und nach unten offene Ölbahn 25 vorgesehen. Diese Ölbahn 25 wird beidseitig, aus dem Eckbereich der Wärmetauschzone K heraus, mit Öl beaufschlagt das über die Durchgangskanäle 17, 22 aus dem Kolbeninnenbereich um die Kolbenbolzennaben 4, 5 herumgeführt ist.In the piston acc. Figure 3 is in the area of the piston ring balcony 7 a trough-like recessed and downwardly open oil path 25 is provided. This oil path 25 is acted upon on both sides, from the corner region of the heat exchange zone K, with oil which is guided around the piston pin hubs 4, 5 via the passage channels 17, 22 out of the inner area of the piston.

Die Geometrie der Ölbahn 25 insbesondere einer äußeren Umfangskante 26 der muldenartigen Vertiefung ist derart festgelegt, dass das zugeführte Öl im wesentlichen parallel zur Oszillationsrichtung des Kolbens nach unten abgeworfen wird. Es ist möglich, diese Ölbahn hinsichtlich ihres Volumens derart groß zu bemessen, dass ein Abwurf des Öles - zumindest zum überwiegenden Teil - erst in einer unteren Totpunktposition des Kolbens erfolgt.The geometry of the oil path 25, in particular an outer peripheral edge 26 of the trough-like depression is set such that the supplied oil is dropped down substantially parallel to the oscillation direction of the piston. It is possible to dimension this oil path in terms of their volume so large that a dropping of the oil - at least for the most part - takes place only in a bottom dead center position of the piston.

Bei der hier gezeigten Ausführungsform beträgt die Tiefe der Ölbahn 25 ca. 8mm. Die in radialer Richtung des Kolbens gemessene Breite der Ölbahn liegt vorzugsweise im Bereich von 4 bis 6mm. Diese Angaben beziehen sich auf einen Kolben mit einem Durchmesser von ca. 80mm. Die in Umfangsrichtung gemessene Länge der Ölbahn 25 entspricht im wesentlichen wenigstens der Breite b der Kolbenbolzennabe 4.In the embodiment shown here, the depth of the oil path 25 is about 8mm. The width of the oil path measured in the radial direction of the piston is preferably in the range of 4 to 6 mm. This information refers to a piston with a diameter of approx. 80mm. The length of the oil path 25 measured in the circumferential direction essentially corresponds at least to the width b of the piston pin hub 4.

In Fig.4 ist eine Detailansicht eines Kolbeninnenbereiches mit einer besonders gestalteten Strahlauftreffzone 10 dargestellt. Die Strahlauftreffzone 10 befindet sich in einem Übergangsbereich zwischen der Innenwand des Kolbenschaftes 3 und der Unterseite des Kolbenkopfes 2. Die mit dem Öl in Kontakt tretenden Wandungsabschnitte bilden eine Ölführungsfläche G die rinnenartig gewölbt ausgebildet ist und in die Innenfläche der Durchgangskanäle 17, 16 übergeht. Die Ölführungsfläche G bewirkt neben einer Führung des Öles auch einen Wärmeübergang auf das Öl und ermöglicht dabei eine Kühlung des benachbarten Kolbenrandbereiches.In Figure 4 a detail view of a piston inner region with a specially designed Strahlauftreffzone 10 is shown. The Strahlauftreffzone 10 is located in a transition region between the inner wall of the piston skirt 3 and the underside of the piston head 2. The coming into contact with the oil wall sections form an oil guide surface G which is formed like a trough and merges into the inner surface of the through channels 17, 16. The oil guide surface G causes not only a guide of the oil but also a heat transfer to the oil, thereby allowing cooling of the adjacent piston edge region.

Die Rinnenwirkung der Ölführungsfläche G wird durch eine Wulstzone 27 unterstützt. Durch die hier gezeigte Ölführungsfläche G wird der auf die Strahlauftreffzone 10 auftreffende Strahl an den Innenkanten der Kolbenbolzennaben 4, 5 vorbei zu einem trichterartigen Eckbereich geführt.The channel effect of the oil guide surface G is supported by a bead zone 27. By the oil guide surface G shown here, the incident on the Strahlauftreffzone 10 beam is guided past the inner edges of the piston pin bosses 4, 5 to a funnel-like corner region.

In Fig.5 ist eine weitere Ausführungsform der Wärmetauschzone K des Kolbenringbalkons 7 dargestellt. Bei dieser Ausführungsform erfolgt eine lediglich einseitige Anströmung der Wärmetauschzone K durch einen aus dem Durchgangskanal 17'gerichtet gerichtet abgestrahlten - hier durch ein Pfeilsymbol angedeuteten - Ölstrom. In der Wärmetauschzone K ist auch bei diesem Ausführungsbeispiel eine schwach zum Kolbenrand hin seitlich ausbauchende Ölbahn 25 ausgebildet. Diese Ölbahn 25 endet in einer Umlenkzone 30 in welcher der ankommende Ölstrom zur Kurbelwelle einer Brennkraftmaschine hin abgelenkt wird. Der Durchgangskanal 17 befindet sich bei diesem Ausführungsbeispiel in einer, einer Kolbendruckseite 31 abgewandten Kolbenhälfte. Hierdurch wird ein verbesserter Schmierfilmaufbau während eines Expansionshubes erreicht.In Figure 5 a further embodiment of the heat exchange zone K of the piston ring balcony 7 is shown. In this embodiment, an only one-sided flow of the heat exchange zone K by a directionally directed from the passage 17 'directed emitted - here by an arrow symbol indicated - oil flow. In the heat exchange zone K, an oil path 25, which bulges laterally slightly towards the edge of the piston, is also formed in this exemplary embodiment. These Oil web 25 ends in a deflection zone 30 in which the incoming oil flow to the crankshaft of an internal combustion engine is deflected out. The passage 17 is located in this embodiment in a, a piston pressure side 31 facing away from the piston half. As a result, an improved lubricating film structure is achieved during an expansion stroke.

In Fig.6 ist eine weitere Ausführungsform eines Kolbens mit einer einseitig durch einen Durchgangskanal 17' angeströmten Unterseite eines Kolbenringbalkons 7, dargestellt. Bei dieser Ausführungsform wird der Ölstrahl 32 über eine in den Kolbenschaft 3 eingeformte Umlenkmulde 33 an der Kolbenbolzenbohrung 6 vorbei umgelenkt. Die Umlenkmulde 33 ist derart ausgebildet, dass der umgelenkte Ölstrahl 32, im wesentlichen parallel zur Zylinderwandung, zur Kurbelwellenlagerung hin abgestrahlt wird. Die Einspeisung des Öles in den Durchgangskanal 17' erfolgt auch bei dieser Ausführungsform durch eine im Innenbereich des Kolbenschaftes 3 vorgesehene Ölführungswandung, wie bei den vorangehend beschriebenen Ausführungsbeispielen.In Figure 6 is a further embodiment of a piston with a unilaterally through a through-channel 17 'flowed underside of a piston ring balcony 7, shown. In this embodiment, the oil jet 32 is deflected over an integrally formed in the piston skirt 3 Umlenkmulde 33 on the piston pin bore 6 over. The Umlenkmulde 33 is formed such that the deflected oil jet 32, substantially parallel to the cylinder wall, is radiated toward the crankshaft bearing. The feeding of the oil into the through-passage 17 'also takes place in this embodiment by means of an oil guide wall provided in the inner region of the piston skirt 3, as in the exemplary embodiments described above.

In den Figuren 7 und 8 ist ein weiteres Ausführungsbeispiel eines Kolbens 1 mit einem Kolbenschaft 3 dargestellt, der im Bereich der Kobenbolzennaben 4, 5 seitlich eingezogen ausgebildet ist. Der Kolbenkopf 2 des Kolbens 1 überkragt hierbei in radialer Richtung den Kolbenschaft 3. Im Bereich der so gebildeten Kolbenringbalkone 7 sind nach außen ausbauchende und nach unten offene Ölbahnen 25 ausgebildet. Der hier stark profiliert ausgebildete, dem Brennraum zugewandte Kolbenkopffläche ist hier um 90° gedreht dargestellt.In the FIGS. 7 and 8 is a further embodiment of a piston 1 is shown with a piston shaft 3, which is formed laterally retracted in the region of the Kobenbolzennaben 4, 5. The piston head 2 of the piston 1 in this case projects over the piston shaft 3 in the radial direction. In the area of the piston ring balconies 7 formed in this way, outwardly bulging and downwardly open oil paths 25 are formed. The here strongly profiled trained, the combustion chamber facing piston head surface is shown here rotated by 90 °.

Diese im Bereich jedes Kolbenringbalkons 7 vorgesehenen Ölbahnen 25 werden über Durchgangskanäle 16, 17 mit Öl gespeist, welches auf eine kolbenrandnahe Strahlauftreffzone 10 durch eine Düse 34 im Bereich einer Kurbelwellenlagerung in den Innenbereich des Kolbenschaftes 3 eingestrahlt wird.These oil passages 25, which are provided in the region of each piston ring balcony 7, are supplied with oil via passage channels 16, 17, which is irradiated onto a region near the piston neck 10 by a nozzle 34 in the region of a crankshaft bearing in the inner region of the piston skirt 3.

Die Zuleitung des aufgestrahlten Öles zu den Durchgangskanälen 16, 17 erfolgt auch hier durch eine Ölführungswandung die sich bis zu den Durchgangskanälen 16, 17 erstreckt. Der Ölpfad im Innenbereich des Kolbenschaftes 3 verläuft im kolbenrandnahen Bereich so daß eine wirkungsvolle Kühlung des gesamten Randbereiches des Kolbenkopfes erreicht wird. Der Ölpfad erstreckt sich in radialer Richtung seitlich ausbauchend, sichelartig um die Kolbenbolzennaben 4, 5 herum. Im Grunde bildet bei dieser Ausführungsform die gesamte nach unten weisende Innenfläche des Kolbenkopfes eine zu den Durchgangskanälen auslaufende Ölführungsfläche. Durch den kolbenringnahen und - von den Abschnitten innerhalb der Durchgangskanäle abgesehen - offenen Ölstrom ergibt sich auf fertigungstechnisch vorteilhafte Weise eine große Wärmetauschfläche.The supply of the radiated oil to the passage channels 16, 17 also takes place here by an oil guide wall which extends to the through channels 16, 17. The oil path in the inner region of the piston skirt 3 extends in the vicinity of the piston skirt so that effective cooling of the entire Edge region of the piston head is achieved. The oil path extends in a radial direction laterally bulging, sickle-like around the piston pin bosses 4, 5 around. Basically, in this embodiment, the entire downwardly facing inner surface of the piston head forms an oil guide surface extending to the passageways. Due to the piston ring near and - apart from the sections within the through channels - open oil flow results in a technically advantageous manner, a large heat exchange surface.

Der erfindungsgemäße Kolben eignet sich aufgrund seines verbesserten Temperaturprofiles und seines geringen Eigengewichtes in besonders vorteilhafter Weise für GDI-Motoren.The piston according to the invention is due to its improved temperature profile and its low weight in a particularly advantageous manner for GDI engines.

Die Erfindung ist nicht auf die vorangehend beschriebenen Ausführungsbeispiele beschränkt. Beispielsweise ist es auch möglich, das auf die Ölführungsfläche abgespritzte Öl aus mehreren, bezüglich ihrer Strahlachse schräg zur Zylinderachse ausgerichteten Ölspritzdüsen abzustrahlen. In Abhängigkeit von der Position des Kolbens kann der Abstand des Strahlauftreffpunktes relativ zu dem Durchgangskanal variieren. Die Ölspritzdüse kann auch am Pleuel selbst angeordnet sein.The invention is not limited to the embodiments described above. For example, it is also possible to emit the oil sprayed onto the oil guide surface from a plurality of oil spray nozzles oriented obliquely relative to the cylinder axis with respect to their jet axis. Depending on the position of the piston, the distance of the beam impact point relative to the passageway may vary. The oil spray nozzle can also be arranged on the connecting rod itself.

Claims (12)

  1. A piston with a piston head (2) and a piston body (3) which comprises a pair of gudgeon pin hubs (4, 5) and is set back in the neighbourhood of the gudgeon pin hubs (4, 5) so that the piston head (2) projects in the radial direction beyond the set-back piston body (3) in the neighbourhood of the gudgeon pin hubs (4, 5), the piston also comprising a interior bounded by the piston body (3) and piston head (2) and containing an oil guide wall which forms an oil-jet impact area (10) the piston also comprising at least one closed passage (16, 17, 22, 22') which extends from the piston interior and is aligned so that the oil flows through the closed passage (16, 17, 22, 22') and comes out through at least one outlet opening (18, 19, 20, 21), and after leaving the closed passage (16, 17, 22, 22') the oil flows to the piston head (2) in the region thereof which projects beyond the piston body (3).
  2. A piston according to claim 1, characterised in that the oil guide wall merges into the inner wall of the closed passage (16, 17, 22, 22').
  3. A piston according to claim 1 or claim 2, characterised in that in the piston head (2) or in the piston body (3) the closed passage (16, 17, 22, 22') bends sideways towards the edge of the piston as it passes the gudgeon pin hubs (4, 5).
  4. A piston according to at least one of claims 1 to 3, characterised in that in a region offset relative to a plane defined by the central axis of the piston and the axis of the gudgeon pin the closed passage (16, 17, 22, 22') extends under the piston body (3) through the piston head (2).
  5. A piston according to at least one of claims 1 to 4, characterised in that the closed passage (16, 17, 22, 22') extends in a crescent past the gudgeon pin hubs (4, 5).
  6. A piston according to at least one of claims 1 to 5, characterised in that the oil guide surface is formed by the inner wall of the piston body (3) in co-operation with the underside of the piston head (2) and comprises a channel area (G) which extends from the oil jet impact area (10) to the closed passage (16, 17, 22, 22').
  7. A piston according to at least one of claims 1 to 6, characterised in that the oil jet impact area (10) is shaped so that it divides the oil jet (9) into at least two component streams (11, 12, 13).
  8. A piston according to claim 7, characterised in that a respective one of the two streams (11, 12) is guided to a region overhanging the piston body.
  9. A piston according to at least one of claims 1 to 8, characterised in that at least one closed passage (16, 17, 22, 22') is provided for each of the regions overhanging the body.
  10. A piston according to at least one of claims 1 to 9, characterised in that a second oil jet impact area is formed in the inner region of the piston body (3).
  11. A piston according to at least one of claims 1 to 10, characterised in that a total of four closed passages (16, 17, 22, 22') are provided and extend round the gudgeon pin hubs (4, 5) to the centroid of the underside of the respective region overhanging the piston body.
  12. A piston according to at least one of claims 1 to 11, characterised in that the cross-section of the closed passages (16, 17, 22, 22') makes up at least 15% of the cross-sectional area of the gudgeon pin bore (6).
EP01130054A 2001-02-13 2001-12-18 Piston for an internal combustion engine Expired - Lifetime EP1231374B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10106435 2001-02-13
DE10106435A DE10106435A1 (en) 2001-02-13 2001-02-13 Pistons, in particular for an internal combustion engine

Publications (3)

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EP1231374A2 EP1231374A2 (en) 2002-08-14
EP1231374A3 EP1231374A3 (en) 2003-05-21
EP1231374B1 true EP1231374B1 (en) 2008-03-05

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP01130054A Expired - Lifetime EP1231374B1 (en) 2001-02-13 2001-12-18 Piston for an internal combustion engine

Country Status (4)

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EP (1) EP1231374B1 (en)
AT (1) ATE388316T1 (en)
DE (2) DE10106435A1 (en)
ES (1) ES2298187T3 (en)

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DE10255892A1 (en) * 2002-11-29 2004-06-09 Mahle Gmbh Piston for combustion engine has oil trap on outer surfaces of boss close to zenith of gudgeon pin borings
DE102004043720A1 (en) 2004-09-09 2006-03-30 Federal-Mogul Nürnberg GmbH Piston for an internal combustion engine and internal combustion engine
JP4379515B2 (en) 2006-12-08 2009-12-09 トヨタ自動車株式会社 Internal combustion engine
JP2013130129A (en) * 2011-12-21 2013-07-04 Kawasaki Heavy Ind Ltd Cooling structure of piston in engine
DE102015203135A1 (en) 2014-02-21 2015-08-27 Ks Kolbenschmidt Gmbh Piston with a flow-friendly oil bearing surfaces having open cooling chamber and a method for cooling this piston
WO2015124748A1 (en) * 2014-02-21 2015-08-27 Ks Kolbenschmidt Gmbh Piston without a closed cooling chamber for internal combustion engines with at least one cooling oil nozzle per cylinder and method for cooling said piston
US10227948B2 (en) 2015-12-18 2019-03-12 Mahle International Gmbh Piston for an internal combustion engine
USD886155S1 (en) 2015-12-18 2020-06-02 Mahle International Gmbh Piston for an internal combustion engine
DE102016204830A1 (en) * 2016-03-23 2017-09-28 Federal-Mogul Nürnberg GmbH Piston for an internal combustion engine
DE102017222743A1 (en) 2017-12-14 2019-06-19 Federal-Mogul Nürnberg GmbH Piston for internal combustion engine

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Also Published As

Publication number Publication date
ES2298187T3 (en) 2008-05-16
EP1231374A3 (en) 2003-05-21
DE10106435A1 (en) 2002-08-14
EP1231374A2 (en) 2002-08-14
DE50113694D1 (en) 2008-04-17
ATE388316T1 (en) 2008-03-15

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