Piston for an internal combustion engine, piston ring for such a piston, internal combustion engine with such a piston, and method for manufacturing a piston or a piston ring

Abstract

Piston (5) for an internal combustion engine (1), comprising at least one piston ring groove (7), and a piston ring (9) partially received in the at least one piston ring groove (7), wherein a circumferentially rotating contact surface (11) of the piston ring (9) bears against a circumferentially rotating counter-contact surface (13) of the piston ring groove (7), wherein a friction pairing between the contact surface (11) and the counter-contact surface (13) in a first region along the circumferential direction is different from the friction pairing in a second region, and wherein the first region and the second region are designed such that an asymmetry is created in the frictional forces acting between the piston ring (9) and the piston ring groove (7), so that when a relative displacement between the piston ring (9) and the piston (5) occurs due to external forces acting on the piston (5) and / or on the piston ring (9), a torque is introduced into the piston ring (9).which, at least on average over time, shows a certain direction.

Description

[0001] The invention relates to a piston for an internal combustion engine, a piston ring for such a piston, an internal combustion engine with such a piston, and a method for manufacturing a piston or a piston ring.

[0002] When operating an internal combustion engine with a combustion chamber containing a piston that can move – particularly with a stroke – a problem arises: lubricating oil can collect in a piston ring groove, which at least partially accommodates a piston ring. Specifically, during a compression stroke, a first compression ring, positioned towards the combustion chamber, scrapes oil from the combustion chamber wall, which then collects in the piston ring groove. This accumulated lubricating oil can eventually enter the combustion chamber and be at least partially combusted, negatively impacting the engine's oil consumption and emissions.Oil droplets entering the combustion chamber can also cause misfires of the combustion air-fuel mixture, which is harmful to emissions and negatively impacts the efficiency of the internal combustion engine. Furthermore, it can place a high mechanical load on the engine, shortening the service life of at least certain engine components. Additionally, there is a risk of carbon buildup in the piston ring grooves, which impairs the functionality of the piston and piston ring assembly.

[0003] The invention is based on the objective of providing a piston for an internal combustion engine, a piston ring for such a piston, an internal combustion engine with such a piston, and a method for manufacturing a piston or a piston ring, wherein the aforementioned disadvantages do not occur or their effects are at least reduced.

[0004] The problem is solved by providing the present technical teaching, in particular the teaching of the independent claims as well as the embodiments disclosed in the dependent claims and the description.

[0005] The problem is solved, in particular, by creating a piston for an internal combustion engine that has at least one piston ring groove and a piston ring that is at least partially received in the at least one piston ring groove. A circumferentially rotating contact surface of the piston ring rests against a circumferentially rotating counter-contact surface of the piston ring groove. The friction pairing between the contact surface and the counter-contact surface in a first region along the circumferential direction differs from the friction pairing in a second region. This creates an asymmetry in the frictional forces acting between the piston ring and the piston ring groove, so that when external forces acting on the piston and / or the piston ring cause a relative displacement between the piston ring and the piston, a torque is introduced into the piston ring, which, at least on average, has a specific direction.This causes the piston ring to rotate within the piston ring groove, directing any lubricating oil entering the groove into the crankcase of the internal combustion engine below the combustion chamber, thus preventing it from accumulating in the groove. This avoids or at least reduces the ingress of lubricating oil into the combustion chamber, positively impacting the engine's oil consumption and preventing or at least reducing harmful emissions. Furthermore, misfires in the combustion chamber are prevented, or at least the risk of their occurrence is reduced. Finally, carbon buildup in the piston ring groove is at least reduced, if not completely prevented, as any accumulated carbon is removed by the rotation of the piston ring, and the piston ring groove is flushed clean by the oil being forced through it towards the crankcase.

[0006] In particular, a so-called blow-by flow of combustion gases acts in this sense, which flows from the combustion chamber through an annular gap or piston ring gap towards the crankcase during the power stroke. The blow-by flow clears the piston ring groove at the position of the piston ring gap. Since the piston ring rotates between the contact surface and the mating contact surface due to the inventive design of the friction pairing according to the invention, the position of the piston ring gap changes circumferentially within the piston ring groove, with the entire circumference of the piston ring groove being swept by the piston ring gap. Thus, the piston ring groove is successively cleared along its entire circumference.

[0007] External forces acting on the piston and / or piston ring, causing relative movement between the piston and the piston ring, occur particularly due to a change in the piston's contact position at its dead centers. Specifically, due to the eccentric connection of the piston to the crankshaft of the internal combustion engine via at least one connecting rod or connecting rod linkage, the piston shifts laterally at its dead centers—even considering the gas forces acting in a combustion chamber associated with the piston—i.e., perpendicular to a longitudinal or symmetry axis of the combustion chamber. At top dead center, this movement is in the opposite direction to that at bottom dead center. The piston ring remains in close contact with the combustion chamber wall throughout the entire stroke of the piston and is therefore not capable of lateral displacement.However, it is held in the piston ring groove with sufficient play to allow the piston to move relative to the piston ring during its changeover. Even in conventional internal combustion engines, this relative movement leads to a slight twisting of the piston ring due to the inherent, slight deviation of the cross-section of the combustion chamber wall, particularly a cylinder liner, from a perfect circle. However, the resulting torque does not cause a full 360° rotation; rather, the piston ring gap moves back and forth within a specific angular range. Therefore, the piston ring gap does not completely traverse the entire circumference of the piston ring groove.

[0008] Only the proposed asymmetrical friction pairing causes a rotational movement of the piston ring gap along a complete, closed circumferential line during the operation of the internal combustion engine, so that over time the entire piston ring groove is swept across by the piston ring gap along its entire circumference. It should also be noted that the torque introduced into the piston ring in the region of top dead center during a combustion cycle of the combustion chamber to which the piston is assigned is significantly higher due to the acting gas forces than the torques introduced into the piston ring during the other cycles and especially at bottom dead center.Thus, the torque is not canceled out by the changes in direction occurring at top dead center on the one hand and at bottom dead center on the other, but rather a torque with a specific preferred direction results in the sum, which at least on average results in a specific rotational movement of the piston ring.

[0009] An axial direction, as used here and in the following, is in particular a direction along which a longitudinal and / or symmetry axis of the combustion chamber to which the piston is assigned extends. This is preferably also a longitudinal or symmetry axis of the piston itself. A radial direction is perpendicular to the axial direction. A circumferential direction encompasses the axial direction concentrically.

[0010] The contact surface is preferably an axial contact surface, in particular an end face of the piston ring, thus a surface whose normal vector is oriented parallel to the axial direction, or on which the axial direction is perpendicular. Particularly preferably, the contact surface is an end face on the underside of the piston ring, also referred to as the underside, where the term "underside" here denotes a side facing away from the combustion chamber and facing the crankcase of the internal combustion engine, this definition being to apply regardless of whether the internal combustion engine is actually oriented such that the crankcase is geodesically located at the bottom and the combustion chamber at the top.

[0011] The mating surface is preferably an axial mating surface, in particular an end face of the piston ring groove, and more preferably a bottom surface, whose normal vector is oriented parallel to the longitudinal axis of the combustion chamber, and preferably also of the piston, so that the longitudinal axis is perpendicular to the mating surface. The mating surface is the end face that delimits the piston ring groove towards the crankcase, and is therefore arranged opposite a roof surface of the piston ring groove, the roof surface delimiting the piston ring groove towards the combustion chamber.

[0012] The first region is, in particular, a first angular region. The second region is, in particular, a second angular region. In particular, the second region is a different region than the first region; the first region and the second region are therefore neither identical nor do they preferentially overlap. In particular, the second region is a different angular region than the first region.

[0013] The first area and the second area are preferably each a continuous area. Particularly preferably, the friction pair has exactly two areas, namely the first area and the second area. In this case, the friction pair is preferably divided along the circumference – preferably exactly halfway – into the two areas.

[0014] The fact that the friction pairing in the first area differs from that in the second area means, in particular, that the coefficient of friction in the first area differs from that in the second area. Specifically, the friction between the piston ring and the piston ring groove is preferably higher in the first area than in the second area, or conversely, it is preferably lower in the first area than in the second area.

[0015] According to a further development of the invention, the contact surface of the piston ring has a first contact surface region in which the contact surface is designed differently with respect to at least one surface property than in a second contact surface region. The first contact surface region is preferably associated with the first region of the friction pairing, and the second contact surface region is associated with the second region of the friction pairing. The first contact surface region and the second contact surface region preferably extend circumferentially and preferably also border each other circumferentially. In this embodiment, it is possible to design the friction pairing in the first region differently from the friction pairing in the second region by modifying the contact surface of the piston ring accordingly with respect to the at least one surface property.The piston ring can be machined or manufactured in a particularly simple way.

[0016] In this embodiment, it is particularly preferred that the mating surface be homogeneous along its entire circumference, meaning that, at least according to its intended design, it has no different mating surface areas and, in particular, consistently homogeneous surface properties. In this case, the asymmetry of the friction pair is introduced exclusively by the piston ring.

[0017] According to a further development of the invention, the mating surface of the piston ring groove has a first mating surface region in which the mating surface is designed differently with respect to at least one surface property than in a second mating surface region. The first mating surface region is preferably associated with the first region of the friction pair, and the second mating surface region is associated with the second region of the friction pair. In particular, the mating surface regions preferably extend circumferentially and, more specifically, border each other circumferentially. The asymmetry in the friction pair is thus introduced in particular by the asymmetrically designed, at least one surface property of the mating surface of the piston ring groove.This is particularly advantageous because, due to the fixed rotational position of the piston, the piston ring groove does not shift circumferentially during a change of contact, so that the asymmetrical design of the friction pair remains spatially constant over time. Thus, taking into account its fixed preferred direction, the change of contact always results in a torque of the same magnitude being introduced into the piston ring.

[0018] If, on the other hand, the asymmetry in the friction pair is solely attributable to the piston ring, it rotates within the piston ring groove. Depending on the orientation of the first and second contact surface areas relative to the preferred direction of contact change, the torque introduced into the piston ring varies in magnitude. The torque is at its maximum when the preferred direction of contact change divides the first and second contact surface areas precisely, i.e., along an imaginary dividing line between the contact surface areas. Conversely, the torque is at its minimum when the piston ring is positioned in a position rotated by 90° relative to this orientation, such that equal areas of the first and second contact surface areas are located on both sides of a diameter line of the piston ring extending along the preferred direction of contact change.However, even then the rotation of the piston ring in the piston ring groove does not come to a standstill, since - as already explained above - the slightly deviating geometry of the combustion chamber wall in itself leads to a rotational movement of the piston ring, so that the corresponding relative position is left again and a certain preferred direction for the torque is established again.

[0019] It is easily recognizable that this complexity is circumvented if the asymmetry in the friction pairing is introduced by appropriate design of the counter-contact surface of the non-rotating piston ring groove.

[0020] Preferably, in this case, the piston ring contact surface is designed to be homogeneous throughout, particularly with consistently homogeneous surface properties, if the mating contact surface has a first mating surface area and a second mating surface area with different surface properties. Thus, in this case, the asymmetry in the friction pair is introduced solely by the piston ring groove.

[0021] However, it is also possible that both the contact surface and the counter-contact surface have different contact area and counter-contact area regions with different surface properties. In this case, the surface properties in the contact area are preferably chosen differently than in the counter-contact area to prevent the corresponding effects on the torque introduced into the piston ring from canceling each other out, at least in one relative position between the piston ring and the piston ring groove.

[0022] According to a further development of the invention, the at least one surface property is selected from a group consisting of a coating, a surface structuring, in particular a microstructuring or adhesion structuring, and a roughness. A microstructuring is in particular a friction-reducing structuring that especially reduces the coefficient of friction. An adhesion structuring is in particular a friction-increasing structuring that especially increases the coefficient of friction.

[0023] Each of the surface properties mentioned here, or a combination of these surface properties, is suitable to influence the friction pairing between the contact surface and the counter-contact surface.

[0024] In particular, at least one of the surface properties expressly mentioned here may be present in one contact surface area or counter-contact surface area, selected from the first contact surface area / counter-contact surface area and the second contact surface area / counter-contact surface area, and absent in the other contact surface area / counter-contact surface area. For example, one of the areas may be coated, and the other area uncoated; or one area may be textured, while the other is untextured. With regard to roughness, one area may have a higher roughness than the other area.

[0025] For example, a coating with a friction-reducing layer, such as DLC (diamond-like carbon), titanium dioxide (TiO2), particularly a fully ceramic titanium dioxide spray coating, or the like, can be provided in a given area. Surface texturing, especially microstructuring, can particularly include the introduction of pits, preferably with a radius of at most 0.1 µm, more preferably from 0.05 µm to 0.1 µm. Such pits can, in particular, serve as a lubricating oil reservoir and thus reduce friction. Of course, surface texturing can also be designed in such a way as to increase friction.

[0026] The difference between the coefficient of friction in the first region and the second region is preferably at least 0.05, preferably from 0.05 to 0.15, preferably up to 0.1. For example, it is possible that the coefficient of friction in the first region is µ = 0.15 and in the second region µ = 0.05, or in the first region µ = 0.1 and in the second region µ = 0.2, or in the first region µ = 0.15 and in the second region µ = 0.1.

[0027] According to a further development of the invention, it is provided that the first contact surface area of ​​the contact surface extends from a first end of the piston ring, which is arranged at the piston ring joint of the piston ring, to a position on the contact surface diametrically opposite the piston ring joint, wherein the second contact surface area preferably adjoins the first contact surface area - in particular directly - and extends from the position diametrically opposite the piston ring joint to a second end of the piston ring, which is arranged at the piston ring joint, namely opposite the first end viewed across the piston ring joint.

[0028] The contact surface is therefore divided in half into the first contact surface area and the second contact surface area, with an imaginary dividing line extending diametrically and centrally through the piston ring gap.

[0029] Alternatively or additionally, it is preferably provided that the first contact surface area of ​​the contact surface extends along the first half of an imaginary closed circumferential line on the contact surface, wherein the second contact surface area extends along the second half of the closed circumferential line on the contact surface. Thus, the contact surface is divided in half into the first contact surface area and the second contact surface area. Preferably, an imaginary diametrical line, which separates the two halves of the closed circumferential line and thus the first contact surface area from the second contact surface area, is oriented perpendicular to a connecting rod eye axis of the piston.The connecting rod eye axis is the imaginary axis that extends as an axis of symmetry through the connecting rod eyes of the piston and thus along the longitudinal extent of a connecting rod pin by which the piston is connected to a connecting rod. Therefore, the imaginary diametrical line, which divides the mating surface into the first mating surface area and the second mating surface area, extends precisely in the preferred direction of the piston's change of contact. This, in turn, ensures that the torque introduced into the piston ring during the change of contact is maximized compared to other possible orientations of the imaginary diametrical line.

[0030] According to a further development of the invention, the piston ring is the uppermost piston ring and the piston ring groove is the uppermost piston ring groove of the piston. Here, an "uppermost" piston ring and an "uppermost" piston ring groove are understood to be a piston ring or piston ring groove that is located closest to the combustion chamber and furthest from the crankcase of all the piston rings / piston ring grooves of the piston. In particular, the uppermost piston ring is a so-called compression ring.

[0031] Particularly preferably, the piston has a total of three piston rings and three piston ring grooves, each assigned separately to the piston rings. In particular, in addition to the compression ring, a compression and scraper ring is provided as the middle piston ring, and an oil scraper ring as the bottom piston ring.

[0032] Alternatively or additionally, it is possible that at least one further or different piston ring and / or at least one further or different piston ring groove is designed according to the invention or according to one of the previously described embodiments. This applies in particular to the compression and scraper ring, and / or to the oil scraper ring.

[0033] The piston ring can therefore alternatively or additionally be a middle and / or bottom piston ring. The piston ring groove can alternatively or additionally be a middle and / or bottom piston ring groove.

[0034] The problem is also solved by creating a piston for an internal combustion engine that has at least one piston ring groove, wherein a circumferentially circumferential counter-contact surface of the piston ring groove has a first counter-contact surface region in which the counter-contact surface is designed differently with respect to at least one surface property than in a second counter-contact surface region of the counter-contact surface. The counter-contact surface is, in particular, the counter-contact surface of the piston ring groove already described previously in connection with the first-described piston according to the invention or the piston preferred according to the invention, in particular an end face of the piston ring groove, and in particular a bottom face. In connection with the piston described here, the advantages already explained in connection with the first-described piston are realized in particular.

[0035] Accordingly, the piston is preferably designed as previously described in connection with the piston first described according to the invention or preferred according to the invention, so that reference is made to the corresponding description.

[0036] In particular, at least one surface property is preferably selected from a group consisting of a coating, a surface structuring, in particular microstructuring or adhesion structuring, and a roughness.

[0037] The first contact surface area preferably extends along the first half of an imaginary closed circumferential line on the contact surface, while the second contact surface area extends along the second half of the closed circumferential line on the contact surface. Thus, the contact surface is divided in half into the first contact surface area and the second contact surface area. Preferably, an imaginary diametrical line, which separates the two halves of the closed circumferential line and thus the first contact surface area from the second contact surface area, is oriented perpendicular to a connecting rod eye axis of the piston.

[0038] The piston ring groove is preferably the uppermost piston ring groove of the piston. Alternatively or additionally, it is possible that the piston ring groove is a middle or a lower piston ring groove of the piston.

[0039] The problem is also solved by creating a piston ring for the piston of an internal combustion engine, wherein the contact surface of the piston ring has a first contact surface region in which the contact surface is designed differently with respect to at least one surface property than in a second contact surface region of the contact surface. The contact surface is, in particular, the contact surface of the piston ring already described in connection with the piston, especially an end face, and in particular an end face on an underside of the piston ring. In connection with the piston ring, the advantages already explained in connection with the piston are realized in particular.

[0040] The piston ring is preferably designed as previously described in connection with the piston ring of the piston, so reference is made to the corresponding description.

[0041] In particular, at least one surface property is preferably selected from a group consisting of a coating, a surface structuring, in particular microstructuring or adhesion structuring, and a roughness.

[0042] The first contact surface area of ​​the contact surface preferably extends from a first end of the piston ring at a piston ring gap to a position on the contact surface diametrically opposite the piston ring gap, wherein the second contact surface area preferably adjoins the first contact surface area - in particular directly - and extends from the position opposite the piston ring gap to a second end of the piston at the piston ring gap, wherein the second end is in particular opposite to the first end at the piston ring gap - viewed in the circumferential direction - i.e. across the piston ring gap.

[0043] The piston ring is preferably the uppermost piston ring, in particular a compression ring for the piston. Alternatively, the piston ring may be a compression and scraper ring, or an oil scraper ring.

[0044] The problem is also solved by creating an internal combustion engine that has a piston according to the invention or a piston according to one of the previously described embodiments. Alternatively or additionally, the internal combustion engine has a piston ring according to the invention or a piston ring according to one of the previously described embodiments. In connection with the internal combustion engine, the advantages that have already been explained in connection with the piston and / or the piston ring become particularly apparent.

[0045] The internal combustion engine has in particular at least one combustion chamber in which a piston, in particular a piston according to the invention or a piston according to one of the previously described embodiments, is displaceable, preferably displaceable by stroke.

[0046] The internal combustion engine is preferably designed as a reciprocating piston engine.

[0047] It preferably has a plurality of combustion chambers, particularly those identical to one another. Specifically, the internal combustion engine may have four, six, eight, ten, twelve, fourteen, sixteen, eighteen, or twenty combustion chambers. Of course, it is also possible for the internal combustion engine to have a different number of combustion chambers, including a larger or smaller number. In particular, each combustion chamber of the internal combustion engine is preferably assigned a piston according to the invention or a piston according to one of the previously described embodiments, and / or at least one piston ring according to the invention or at least one piston ring according to one of the previously described embodiments.

[0048] According to a further development of the invention, the internal combustion engine is designed as a diesel engine or a gas engine. The advantages described above are particularly realized in connection with this type of internal combustion engine.

[0049] The at least one combustion chamber of the internal combustion engine preferably has a diameter of at least 130 mm to at most 1000 mm, preferably at least 170 mm to at most 900 mm, preferably at least 200 mm to at most 800 mm, preferably at least 300 mm to at most 700 mm, preferably at least 400 mm to at most 600 mm, and preferably 500 mm. The advantages already mentioned are particularly evident in combustion chambers of this size.

[0050] The internal combustion engine is therefore preferably designed as a large engine, especially as a medium-speed or slow-speed engine.

[0051] The problem is ultimately solved by providing a method for manufacturing a piston for an internal combustion engine or for manufacturing a piston ring for a piston of an internal combustion engine, wherein, within the framework of the method, a) a first contact surface region of a contact surface of the piston ring is designed differently with respect to at least one surface property than a second contact surface region of the contact surface of the piston ring, or b) a first counter-contact surface region of a counter-contact surface of a piston ring groove of the piston is designed differently with respect to at least one surface property than a second counter-contact surface region of the counter-contact surface of the piston ring groove. In this way, in particular, a piston according to the invention or a piston according to one of the previously described embodiments, or a piston ring according to the invention or a piston ring according to one of the previously described embodiments, is obtained.

[0052] The at least one surface property is in particular selected from a group consisting of a coating, a surface structuring, in particular microstructuring, a roughness, and an adhesion structuring.

[0053] In connection with this method, the advantages already explained in connection with the piston and / or the piston ring and / or the internal combustion engine are particularly realized. In particular, the method preferably produces a piston according to the invention or a piston according to one of the previously described embodiments, or it preferably produces a piston ring according to the invention or a piston ring according to one of the previously described embodiments.

[0054] The invention will be explained in more detail below with reference to the drawing. The drawing shows: Fig. 1 a schematic representation of an embodiment of an internal combustion engine with one piston and one piston ring; Fig. 2 a schematic representation of an exemplary embodiment of a piston ring, and Fig. 3 a schematic representation of an exemplary embodiment of a piston.

[0055] Fig. Figure 1 shows a schematic representation of an embodiment of an internal combustion engine. 1 with a combustion chamber 3 , in which a piston 5 It is movable, in particular movable by stroke. The internal combustion engine 1 It is therefore designed in particular as a reciprocating piston engine, preferably as a diesel engine or gas engine.

[0056] Preferably the internal combustion engine 1 a plurality of combustion chambers 3on, in particular four, six, eight, ten, twelve, fourteen, sixteen, eighteen or twenty combustion chambers, or even more combustion chambers, fewer combustion chambers, or another number of combustion chambers.

[0057] A diameter of the combustion chamber 3 The diameter is preferably at least 130 mm to at most 1000 mm, preferably at least 170 mm to at most 900 mm, preferably at least 200 mm to at most 800 mm, preferably at least 300 mm to at most 700 mm, preferably at least 400 mm to at most 600 mm, preferably 500 mm. The internal combustion engine 1 is designed in particular as a large engine, preferably as a medium-speed or slow-speed engine.

[0058] The piston 5 has at least one piston ring groove 7 up. In the piston ring groove 7 is at least partially a piston ring 9 recorded, which has a circumferentially surrounding mounting surface 11on a counter-surface that also runs circumferentially 13 the piston ring groove 7 This involves a friction pairing between the contact surface. 11 and the counter-surface 13 In a first region, particularly in a first angular region, the friction pairing differs along the circumferential direction from that in a second, different region, particularly in a second angular region. This advantageously creates an asymmetry in the friction pairing along the circumference of the piston ring groove. 7 and / or the piston ring 9 provided so that externally on the piston 5 and / or the piston ring 9 acting forces, for example during a change of piston position 5 , due to a relative displacement between the piston 5 and the piston ring 9 a torque in the piston ring 9is initiated so that it is caused to rotate - at least on average over time - whereby the piston ring 9 Over time, it completes a full rotation, that is, a complete 360° turn. Thus, in particular, one piston ring stroke covers... 23 of the piston ring 9 the piston ring groove 7 along an entire closed circumferential line, so that in the piston ring groove 7 accumulated lubricating oil can be driven towards a crankcase and not remain in the piston ring groove. 7 This collects. This prevents lubricating oil from entering the combustion chamber. 3 Advantageously reduced or even completely avoided, thereby also preventing carbon build-up in the piston ring groove 7 This avoids or at least reduces existing carbon deposits, while at the same time the rotation of the piston ring also removes any carbon buildup that has already occurred. 9 is scraped off and conveyed away towards the crankcase.

[0059] Fig. Figure 2 shows an illustration of an embodiment of the piston ring. 9 .

[0060] Identical and functionally equivalent elements are provided with the same reference symbols in all figures, so that reference is made to the preceding description in each case.

[0061] In the exemplary embodiment of the piston ring 9 according to Fig. 2 indicates the planting area 11 a first investment area 15 and a second investment area 17 on, whereby in the first plant area 15 at least one surface property is different from that in the second application area 17 The plant area areas are bordered by... 15 , 17 viewed in the circumferential direction, they abut each other. The use of such a piston ring can be advantageous in several ways. 9 the counter-surface 13 the piston ring groove 7They must be consistently homogeneous with respect to their surface properties. However, it is also possible that the mating surface may also be homogeneous. 13 various counter-surface areas 31 , 33 exhibits which differ with regard to at least one surface property, wherein this surface property is then advantageously chosen differently from the corresponding surface property of the piston ring. 9 , or at least the counter-investment areas are 31 , 33 with respect to the same surface property, it is designed differently in terms of quantity than the piston ring. 9 This is the case. Therefore, a uniform or identical design of the plant areas is preferred. 15 , 17 of the piston ring 9 on the one hand and the counter-project areas 31 , 33 the piston ring groove 7 On the other hand, it was avoided.

[0062] The at least one surface property is preferably selected from a group consisting of a coating, a surface structuring, in particular a microstructuring or an adhesion structuring, and a roughness.

[0063] In the embodiment shown here, the second attachment area 17 with a microstructuring in the form of cups 19 equipped, although for better clarity only one of the bowls 19 is marked with the corresponding reference symbol. Such microstructures are in the form of pits. 19 They can, for example, act as oil-retaining structures and thus reduce friction in the area of ​​the second contact surface. 17 reduce it. Alternatively, it is also possible to design the surface texture to result in increased roughness. This can also be done in the second application area. 17 or in the first plant area15 a coating may be provided which increases or - in a particularly preferred embodiment - reduces friction, for example a DLC coating or a coating with TiO2, in particular a full ceramic titanium dioxide spray coating.

[0064] The first investment area 15 the site 11 extends from a first end 21 of the piston ring, which is located at the piston ring joint 23 is arranged up to a piston ring gap 23 diametrically opposite position 25 on the site 11 The second planting area 17 This area directly adjoins the first construction area. 15 and extends from the piston ring gap 23 diametrically opposite position 25 to a second end 27 of the piston ring 9 , where the second end 27also at the piston ring gap 23 is arranged. The first end 21 and the second end 27 They lie along the piston ring gap. 23 seen, that is, in the circumferential direction, opposite.

[0065] In Fig. 2 is also an imaginary dividing line. 29 drawn, the one through the center of the piston ring gap 23 runs and a diameter line of the piston ring 9 is, where the dividing line 29 the first investment area 15 and the second planting area 17 separates them.

[0066] The piston ring 9 is preferred as the top piston ring 9 , especially as a compressor ring. However, it is also possible that the piston ring 9 as a compression and scraper ring, and therefore especially as the middle piston ring 9 , or as an oil scraper ring, especially as the bottom piston ring 9, for the piston 5 , is trained.

[0067] Fig. Figure 3 shows an illustration of an exemplary embodiment of a piston. 5 for the internal combustion engine 1 The counter-surface 13 This indicates a first counter-investment area 31 and a second counter-installation area 33 on, whereby the counter surface 13 in the first counter-surface area 31 with regard to at least one surface property, it is designed differently than in the second counter-surface area 33 The counter-projection areas are bordered by... 31 , 33 viewed in the circumferential direction – in particular directly – against each other. It is preferred when using such a piston 5 the site 11 one in the piston ring groove 7 piston ring to be arranged 9The surface properties are consistently homogeneous. However, if it should also exhibit an asymmetry with respect to at least one surface property, this property preferably differs from that of the mating surface. 13 introduced asymmetry at least with regard to at least one surface property, as previously discussed in connection with the piston ring 9 was explained.

[0068] The first counter-attachment area 31 preferably extends along the first half of an imaginary closed perimeter line on the opposite mounting surface 13 , whereby the second counter-surface area 33 along a second half of the imaginary closed perimeter line on the opposite surface 13 extends. In Fig. 3 is also an imaginary diametrical line separating the two halves of the closed perimeter line. 35drawn, where these are perpendicular to a connecting rod eye axis P of the piston. 5 stands.

[0069] The diametrical line 35 extends in particular along a preferred direction, along which a change in the piston's position occurs. 5 at the dead centers of the piston movement. The corresponding arrangement of the counter-contact surfaces. 31 , 33 each lateral to the diametral line 35 In this case, compared to other possible arrangements of the diametral line, this allows 35 relative to the preferred direction of the system change - a maximization of the pressure in the piston ring 9 applied torque.

[0070] In this case as well, at least one surface property is preferably selected from the group consisting of a coating, a surface structuring (in particular microstructuring or adhesion structuring), and a roughness. Here too, in the illustrated embodiment, cups are an example. 19 into the opposite surface 13 in the area of ​​the second counter-installation area 33 introduced, whereby alternatively - as in connection with the piston 9 explained - including roughening, an adhesion-reducing coating, or any other type of modification of the mating surface 13 in the area of ​​the second counter-installation area 33 , or also the first counter-project area 31 , possible.

[0071] The piston ring groove 7 is preferably a top piston ring groove of the piston 5Alternatively or additionally, it is possible that a middle piston ring groove 37 or a bottom piston ring groove 39 is / are designed accordingly.

[0072] A piston ring according to the invention 9 is preferably produced by the plant area 11 of the piston ring 9 regarding at least one surface property in the first planting area 15 is designed differently than in the second plant area 17 .

[0073] A piston according to the invention 5 is preferably produced by the counter-surface 13 the piston ring groove 7 regarding at least one surface property in the first counter-surface area 31 is formed differently than in the second counter-surface area 33 .

[0074] With the piston proposed here 5 , the piston ring 9, the internal combustion engine 1 as well as the method for manufacturing a piston 5 or piston rings 9 A way is created to reduce the lubricating oil consumption of the internal combustion engine. 1 at least to reduce misfires due to emissions into the combustion chamber 3 to prevent penetrating lubricating oil and carbon buildup in the piston ring groove 7 to reduce, preferably to avoid.

Claims

[1] Piston (5) for an internal combustion engine (1), with - at least one piston ring groove (7), and - a piston ring (9) partially received in at least one piston ring groove (7), wherein - a circumferentially circumferential contact surface (11) of the piston ring (9) rests against a circumferentially circumferentially circumferential counter-contact surface (13) of the piston ring groove (7), wherein - a friction pairing between the contact surface (11) and the counter contact surface (13) in a first area along the circumferential direction is different from the friction pairing in a second area. [2] Piston (5) according to claim 1, characterized by , that the contact surface (11) of the piston ring (9) has a first contact surface area (15) in which the contact surface (11) is designed differently with respect to at least one surface property than in a second contact surface area (17) of the contact surface (11). [3] Piston (5) according to any one of the preceding claims, characterized by , that the counter-contact surface (13) of the piston ring groove (7) has a first counter-contact surface area (31) in which the counter-contact surface (13) is designed differently with respect to at least one surface property than in a second counter-contact surface area (33) of the counter-contact surface (13). [4] Piston (5) according to any one of the preceding claims, characterized by , that at least one surface property is selected from a group consisting of a coating, a surface structuring, a roughness, and an adhesion structuring. [5] Piston (5) according to any one of the preceding claims, characterized by , that a) the first contact surface area (15) of the contact surface (11) extends from a first end (21) of the piston ring (9) at a piston ring gap (23) of the piston ring (9) to a position (25) on the contact surface (11) diametrically opposite the piston ring gap (23), wherein the second contact surface area (17) preferably adjoins the first contact surface area (15) and extends from the position (25) diametrically opposite the piston ring gap (23) to a second end (27) of the piston ring (9) at the piston ring gap (23), and / or b) the first counter-contact area (31) of the counter-contact area (13) extends along a first half of a closed circumferential line on the counter-contact area (13), wherein the second counter-contact area (33) of the counter-contact area (13) extends along a second half of the closed circumferential line on the counter-contact area (13), wherein preferably a diametral line (35) separating the two halves of the closed circumferential line is perpendicular to a connecting rod eye axis (P) of the piston (5). [6] Piston (5) according to any one of the preceding claims, characterized by , that the piston ring (9) is an uppermost piston ring (9) and the piston ring groove (7) is an uppermost piston ring groove (7) of the piston (5). [7] Piston (5) for an internal combustion engine (1), having at least one piston ring groove (7), wherein - the piston ring groove (7) has a counter-contact surface (13) for contact of a contact surface (11) of a piston ring (9) on the counter-contact surface (13), wherein the counter-contact surface (13) has a first counter-contact surface area (31) and a second counter-contact surface area (33), wherein the counter-contact surface (13) in the first counter-contact surface area (31) is designed differently with respect to at least one surface property than in the second counter-contact surface area (33). [8] Piston ring (9) for a piston (5) of an internal combustion engine (1), wherein - the piston ring (9) has a contact surface (11) with a first contact surface area (15), wherein the contact surface (11) in the first contact surface area (15) is designed differently with respect to at least one surface property than in a second contact surface area (17) of the contact surface (11). [9] Internal combustion engine (1), comprising a piston (5) according to any one of claims 1 to 7, and / or a piston ring (9) according to claim 8. [10] Internal combustion engine (1) according to claim 9, characterized by , that the internal combustion engine (1) is designed as a diesel engine or as a gas engine. [11] Method for manufacturing a piston (5) for an internal combustion engine (1) or for manufacturing a piston ring (9) for a piston (5) of an internal combustion engine (1), wherein a) a first contact surface area (15) of a contact surface (11) of the piston ring (9) is designed differently with respect to at least one surface property than a second contact surface area (17) of the contact surface (11), or b) a first counter-contact surface area (31) of a counter-contact surface (13) of a piston ring groove (7) of the piston (5) is designed differently with respect to at least one surface property than a second counter-contact surface area (33) of the counter-contact surface (13).

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