System and method with an anti-polishing ring for a piston

Abstract

A system comprises a cylinder liner assembly configured to line a cylinder around a piston with a tight clearance between the piston crown and the cylinder liner. The cylinder liner assembly includes a cylinder liner with an inner running surface extending circumferentially around a central axis and an anti-polishing ring.

Description

BACKGROUND

[0001] The subject matter disclosed herein relates to reciprocating pistons and in particular to a system and a method for reducing carbon formation on an outer surface of a piston.

[0002] Pistons are used in a variety of machines, such as pumps, compressors, and piston-cylinder internal combustion engines (i.e., reciprocating engines). In reciprocating engines, carbon deposits can accumulate around the circumference of the piston's upper surface due to fuel combustion. The accumulation of carbon deposits leads to a polishing of the cylinder liner (e.g., bore polishing) due to friction between the piston and cylinder liner. Over time, this polishing can lead to increased emissions and potential damage to the reciprocating engine. Therefore, there is a need to reduce carbon buildup on the outer surface of pistons. SHORT DESCRIPTION

[0003] Certain embodiments corresponding to the scope of the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but merely to provide a brief summary of possible forms of the present disclosure. In fact, the present disclosure may comprise a multitude of forms that may be similar to or different from the embodiments shown below.

[0004] In one embodiment, a system comprises a cylinder liner assembly configured to line a cylinder around a piston with a tight clearance between the piston crown and the cylinder liner. The cylinder liner assembly includes a cylinder liner with an inner running surface extending circumferentially around a central axis and an anti-polishing ring.

[0005] In another embodiment, a system comprises a piston with a tight clearance between the piston crown and the cylinder liner. The system also includes a cylinder liner. The cylinder liner includes an anti-polishing ring with a conical section. The conical section is configured to overlap the piston with the tight clearance between the piston crown and the cylinder liner when the piston is in a top dead center position.

[0006] In a further embodiment, a method comprises providing a cylinder liner having an inner running surface extending circumferentially around a central axis. The method further comprises providing an anti-polishing ring, wherein the cylinder liner and the anti-polishing ring are parts of a cylinder liner assembly configured to line a cylinder around a piston with a tight clearance between the piston crown and the cylinder liner. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects and advantages of the present invention will be better understood if the following detailed description is read with reference to the accompanying drawings, in which identical symbols denote identical parts, wherein the following applies: Fig. Figure 1 is a schematic representation of an embodiment of a reciprocating piston engine coupled to a load according to aspects of the present disclosure; Fig. Figure 2 is a cross-sectional side view of an exemplary embodiment of a piston inside a cylinder of the in Fig. 1 reciprocating engine shown according to aspects of the present disclosure; Fig. Figure 3 is a cross-sectional side view of an embodiment of the piston of Fig. 2 and a cylinder liner assembly comprising a liner and an anti-polishing ring (anti-polishing ring) according to aspects of the present disclosure; Fig. Figure 4 is a top view of an embodiment of the piston and cylinder liner assembly of Fig. 3 according to aspects of the present revelation; Fig. Figure 5 is a partial cross-sectional view of an embodiment of the anti-polishing ring, showing a frustoconic shape; Fig. Figure 6 is a partial cross-sectional view of an embodiment of the anti-polishing ring 84, which shows a cylindrical and frustoconic shape; Fig. Figure 7 is a partial cross-sectional view of an embodiment of the anti-polishing ring, showing a stepped frustoconic shape; Fig. Figure 8 is a partial cross-sectional view of an embodiment of the anti-polishing ring, showing an outwardly curved shape; Fig. Figure 9 is a partial cross-sectional view of an embodiment of the anti-polishing ring, showing an inwardly curved shape; Fig. Figure 10 is a partial cross-sectional view of an embodiment of the anti-polishing ring, which has a complex shape with aspects of Fig. 6, Fig. 7, Fig. 8 and Fig. 9 shows; Fig. Figure 11 is a graphic of the minimum radial protrusions for reducing bore polishing relative to a height from the base of the protrusion for various circumferential positions of the anti-polishing ring according to aspects of the present disclosure. Fig. Figure 12 is a graphic of the minimum radial protrusions for reducing bore polishing relative to the circumferential position of the anti-polishing ring according to aspects of the present disclosure; and Fig. Figure 13 is an example process for forming an inner radial surface of the anti-polishing ring according to aspects of the present disclosure. DETAILED DESCRIPTION

[0008] One or more specific embodiments of the present invention are described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation may be described in the specification. It should be noted that, as with any engineering or design project, the development of any such actual implementation requires numerous implementation-specific decisions to be made in order to achieve the specific goals of the developers, such as compliance with system-relevant and business-related constraints, which may vary from one implementation to another.Furthermore, it should be taken into account that while such development work may be complex and time-consuming, for professionals who have the advantage of this revelation it is a routine task in terms of development, manufacturing and production.

[0009] When introducing elements of various embodiments of the present invention, the articles "a," "the," and "the aforementioned" mean that one or more of these elements are present. The terms "comprising," "including," and "comprising / with" are to be understood as inclusive and mean that there may be further elements in addition to those listed.

[0010] The disclosed embodiments provide a system and a method for using a piston (e.g., a piston with tight clearance between the piston crown and the cylinder liner [TLL]) with a cylinder liner assembly having a positioned (e.g., indexed) anti-polishing ring with a projection, wherein the positioning or indexing can be achieved by one or more fasteners that maintain a circumferential position of the anti-polishing ring. By attaching the anti-polishing ring to the cylinder liner, the cylinder liner assembly can be honed in a single liner setup, thereby reducing the concentricity misalignment between the anti-polishing ring and the cylinder liner. Furthermore, separating the anti-polishing ring from the cylinder liner can facilitate the removal of the piston from the cylinder liner (e.g.,The anti-polishing ring with the protrusion, as shown here, also reduces bore polishing of the cylinder liner by minimizing the formation of carbon deposits around the piston.

[0011] Embodiments of the cylinder liner assembly may include an anti-polishing ring coupled to an upper section of a cylinder liner that includes a piston. The cylinder liner assembly may be used in any suitable machine, including, but not limited to, a reciprocating engine, a pump, or a compressor. However, the cylinder liner assembly may be particularly well suited for reducing carbon deposits in reciprocating engines. The anti-polishing ring may be coupled to the cylinder liner by one or more fasteners, or, in certain embodiments, form a single part (e.g., a single through-piece) with the cylinder liner. The anti-polishing ring (e.g., annular anti-polishing ring) of the cylinder liner assembly includes a conical section, and, in certain embodiments, an upper section that is directly coupled to the conical section.The conical section and the upper section are configured to project radially inward from an inner cylinder liner surface. A projection gap extending from the inner cylinder liner surface to an upper inner surface of the upper section and / or a conical inner surface of the conical section is configured to decrease from a top surface of the cylinder liner assembly in the downward direction of the piston. That is, the combined profile of the upper inner surface and the conical inner surface results in reduced clearance between the anti-polishing ring and the upper piston land when the piston is at top dead center.

[0012] As disclosed herein, the shape of the anti-polishing ring protrusion can assume a combination of shapes. For example, the protrusion shape can be frustoconic, frustoconic with a radial step, outwardly curved, inwardly curved, or a combination thereof. It should also be noted that the protrusion shape can vary around a circumferential direction of the anti-polishing ring. In certain embodiments, a simulation can be performed to empirically determine a variety of minimum protrusion spacings for reducing bore polishing. In certain embodiments, the variety of minimum protrusion spacings can vary irregularly (e.g., non-repeatably) around a circumferential direction of the anti-polishing ring. For example, due to thermal deformations and the positioning of the piston within the cylinder liner (e.g.,(From the push side to the anti-push side of the piston) the clearance between the piston and cylinder liner varies irregularly in the circumferential direction around the piston. Therefore, the multitude of minimal protrusion gaps of the anti-polishing ring can be contoured or adapted to thermal deformations and the positioning of the piston within the cylinder liner in such a way that the clearance between the anti-polishing ring and the piston is essentially uniform (e.g., plus or minus 1, 2, 3, 4, or 5 percent relative to an average clearance) around the circumferential direction of the piston and the anti-polishing ring.

[0013] The drawings show in Fig. Figure 1 shows a schematic representation of an embodiment of a reciprocating piston system 8 with one or more anti-polishing ring(s). Fig. Figure 1 is intended to provide context for the anti-polishing rings, which are explained in more detail below. In certain embodiments, the reciprocating piston system 8 comprises an engine 10 (e.g., a reciprocating piston-cylinder internal combustion engine or a reciprocating piston engine) with one or more combustion chamber(s) 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, or more combustion chambers 12). An air supply 14 is configured to supply each combustion chamber 12 with a pressurized oxidizer 16, such as air, oxygen, oxygen-enriched air, oxygen-reduced air, or any combination thereof. Any suitable oxidizer can be used with the disclosed embodiments. The combustion chamber 12 is also configured to supply a fuel 18 (e.g.,a liquid and / or gaseous fuel (hydrogen) is drawn from a fuel supply 19, and a fuel-air mixture ignites and burns within each combustion chamber 12. The fuel 18 can be any suitable gaseous fuel, such as natural gas, associated petroleum gas, propane, biogas, sewage gas, landfill gas, or mine gas. The hot, pressurized combustion gases cause a piston 20, adjacent to each combustion chamber 12, to move linearly or axially back and forth within a cylinder 26, converting the pressure exerted by the combustion gases into a rotational motion that sets a shaft 22 (e.g., a crankshaft) into rotation. Furthermore, the shaft 22 can be coupled to a load 24, which is driven by the rotation of the shaft 22.For example, the load 24 can be any suitable device that can generate energy via the rotational power of the system 10, such as an electric generator, a rotary compressor, a rotary pump or other machines.

[0014] In certain embodiments, the piston 20 may comprise a piston with tight clearance between the piston crown and the cylinder liner (TTL). A TTL piston is a piston with a diametrical clearance of the upper piston land at the top edge of the upper piston land that is less than or equal to 0.34% of the bore diameter for steel or cast iron in the cold state. In certain embodiments, the diametrical clearance of the top edge of the upper piston land may be less than or equal to 0.34%, 0.33%, 0.32%, 0.31%, 0.30%, 0.29%, 0.28%, 0.27%, or 0.26% of the bore diameter for steel or cast iron in the cold state. The diametrical clearance of the upper piston land at the top edge of the upper piston land should be less than or equal to 0.60% of the bore diameter for aluminum in the cold state.In certain embodiments, the diametrical clearance of the upper piston land at the top edge of the upper piston land can be less than or equal to 0.60%, 0.59%, 0.58%, 0.57%, 0.56%, 0.55%, 0.54%, 0.53%, 0.52%, 0.51%, 0.50%, 0.49%, 0.48%, 0.47%, or 0.46% of the bore diameter for aluminum in the cold state. The bearing clearances of the upper piston land under operating conditions (i.e., bearing clearances under heat) decrease due to thermal expansion. The typical range for radial clearances under heat varies between approximately 25 µm and 75 µm.

[0015] The reciprocating piston system 8 described herein can be adapted for use in stationary applications (e.g., in industrial power generation engines) or in mobile applications (e.g., in cars or aircraft). The engine 10 can be a two-stroke, three-stroke, four-stroke, five-stroke, or six-stroke engine. The engine 10 can also include any number of combustion chambers 12, pistons 20, and associated cylinders (e.g., 1–24). For example, in certain embodiments, the reciprocating piston system 8 can include a large-scale industrial reciprocating piston engine with 4, 6, 8, 10, 16, 24, or more pistons 20 moving back and forth in cylinders 26. In some such cases, the cylinders 26 and / or the pistons 20 can have a diameter between approximately 13.5 and 34 centimeters (cm). In some embodiments, the cylinders and / or the pistons 20 can have a diameter between about 10 and 40 cm, 15 and 25 cm or about 15 cm.System 10 can generate a power output in the range of 10 kW to 10 MW. In some embodiments, the motor 10 can be operated at less than approximately 1800 revolutions per minute (rpm). In some embodiments, the motor 10 can be operated at less than approximately 2000 rpm, 1900 rpm, 1700 rpm, 1600 rpm, 1500 rpm, 1400 rpm, 1300 rpm, 1200 rpm, 1000 rpm, 900 rpm, or 750 rpm. In some embodiments, the motor 10 can be operated between approximately 750 and 2000 rpm, 900 and 1800 rpm, or 1000 and 1600 rpm. In some embodiments, the motor 10 can be operated at approximately 1800 rpm, 1500 rpm, 1200 rpm, 1000 rpm, or 900 rpm. In certain embodiments, the motors 10 can comprise Jenbacher motors (e.g., Jenbacher Type 2, Type 3, Type 4, Type 6, or J920 FleXtra) or Waukesha motors (e.g., Waukesha VGF, VHP, APG, 275GL), manufactured by INNIO in Jenbach, Austria.

[0016] The driven power generation system 8 can include one or more sensors 23 that are communicatively coupled to an engine control unit (ECU) or a controller 25. The sensors 23 can include temperature sensors, pressure sensors, flow sensors, fuel composition sensors, knock sensors, oxygen sensors, emission sensors, or any combination thereof. For example, the knock sensors are suitable for detecting engine knocking. The emission sensors can include nitrogen oxide (NOx) sensors, carbon oxide (COx) sensors, sulfur oxide (SOx) sensors, or any combination thereof. The temperature, pressure, and flow sensors can be configured to monitor the temperature, pressure, and flow rate of a coolant and / or lubricant through the engine 10, for example, through the engine block, valve head, pistons 20 (e.g., cylinders, cylinders, etc.).through a coolant channel into the piston 20) or any combination thereof. During operation of the engine 10, signals from the sensors 23 are transmitted to the control unit 25 to evaluate various states of the engine 10 and to adjust operating parameters of the engine 10, including, but not limited to, a coolant flow rate, a lubricant flow rate, a fuel injection quantity and / or fuel injection timing, an ignition timing, a boost pressure of the intake air introduced into the engine 10, or any combination thereof.

[0017] Fig. Figure 2 is a cross-sectional side view of an embodiment of a piston assembly 25 with a piston 20 arranged in a cylinder 26 (e.g., an engine cylinder) of the engine 10. The cylinder 26 has an inner annular wall 28 that defines a cylindrical cavity 30 (e.g., a bore), wherein the inner annular wall 28 contains a cylinder liner with an anti-polishing ring. Various aspects of the cylinder liner and the anti-polishing ring are explained in more detail below. The piston 20 can be defined by an axial axis or direction 34, a radial axis or direction 36, and a circumferential axis or direction 38. The piston 20 includes an upper or top section 40 (e.g., an upper piston land or piston crown). The uppermost section 40 generally prevents the fuel 18 and air 16 or a fuel-air mixture from escaping from the combustion chamber 12 during the reciprocating movement of the piston 20.The piston 20 further comprises a lower bottom or body section 41, which is connected to the upper section 40. For example, as explained in detail below, sections 40 and 41 of the piston 20 may be coupled to each other via a hinge, or sections 40 and 41 may together form a single-piece structure. Additionally, sections 40 and 41 of the piston 20 may define a coolant channel within the piston 20.

[0018] As shown, the piston 20 is connected to a crankshaft 54 ​​via a connecting rod 56 and a pin 58. The crankshaft 54 ​​converts the reciprocating linear motion of the piston 24 into a rotational motion. When the piston 20 moves, the crankshaft 54 ​​rotates to actuate the load 24 (shown in Fig. 1) to drive, as described above. As shown, the combustion chamber 12 is positioned next to the upper piston land 40 of the piston 24 (which should be numbered 20, right?). A fuel injector 60 supplies the combustion chamber 12 with fuel 18, and an inlet valve 62 controls the supply of air 16 to the combustion chamber 12. An exhaust valve 64 controls the exhaust gas discharge from the engine 10. However, any suitable elements and / or techniques for supplying fuel 18 and air 16 to the combustion chamber 12 and / or for exhaust gas discharge in the engine 10 can be used. During operation, the combustion of the fuel 18 with the air 16 in the combustion chamber 12 causes the piston 20 to move back and forth in the axial direction 34 within the cavity 30 of the cylinder 26 (e.g., back and forth). During operation, when the piston 20 is at its highest point in the cylinder 26, it is in a position known as top dead center (TDC).When the piston 20 is at its lowest point in the cylinder 26, it is in a position known as bottom dead center (BDC). As the piston 20 moves up and down or down and up, the crankshaft 54 ​​rotates half a revolution. Each up and down movement of the piston 20 is called a stroke, and embodiments of the engine 10 may include two-stroke, three-stroke, four-stroke, five-stroke, six-stroke, or more.

[0019] Fig. Figure 3 is a partial cross-sectional side view of an embodiment of the piston 20, which is located in the Fig. The cylinder 26 is arranged as shown in Figure 2, with details of a cylinder liner assembly 80, which is coupled to the cylinder 26 and lines its interior, being shown in more detail. As shown, the cylinder liner assembly 80 includes a cylinder liner 82 (e.g., an annular cylinder liner, an annular cylinder liner, or a cylinder liner), an anti-polishing ring 84, and a seal 85. In certain embodiments, the cylinder liner assembly 80 can be in the form of a kit containing the cylinder liner 82, the anti-polishing ring 84, and the seal 85. The cylinder liner 82 includes an inner liner surface 86 (e.g., an annular inner liner surface, annular inner surface, inner surface, etc.). The anti-polishing ring 84 includes an upper section 88 (e.g., an annular upper section) and a conical section 90 (e.g., a tapered section).an annular conical section) extending from the upper section 88 in a downward direction 92 of the piston 20, opposite to the direction 34. In the illustrated embodiment, the conical section 90 includes a conical inner surface 94 (e.g., an annular conical inner surface, an annular conical surface, or a frustoconical inner surface), and the upper section 88 includes an upper inner surface 95 (e.g., an annular inner surface, an annular upper inner surface, or an annular upper surface). As shown, the upper inner surface 95 is substantially axially parallel to a longitudinal center axis 97 of the piston 20. In certain embodiments, the upper section 88 is omitted from the anti-polishing ring 84.

[0020] In the illustrated embodiment, an anti-polishing ring height 96 extends from an upper surface 98 of the anti-polishing ring 84 to a lower surface 100 of the anti-polishing ring 84. Additionally, an upper section height 102 extends from the upper surface 98 of the anti-polishing ring 84 to a transition height 104, which defines a lower end of the upper inner surface 95 and an upper end of the conical inner surface 94. In certain embodiments, the height 96 of the anti-polishing ring can be less than 10, 15, 20, 25, 30, 35, or 40 millimeters. In certain embodiments, the height 102 of the upper section can be less than 3, 5, 8, 10, 12, 15, or 18 millimeters in length. In certain embodiments, the ratio between the height 102 of the upper section (e.g., first axial length) and the height 96 of the anti-polishing ring (e.g., second axial length) is between 1:2 and 3:4, between 3:5 and 7:10 and / or between 11:18 and 13:18.

[0021] In the illustrated embodiment, a maximum projection distance 106 of the anti-polishing ring 84 is measured from a lower intersection point 108 of the lower surface 100 and the conical inner surface 94 and the upper inner surface 95 of the upper section 88. A conical projection distance 112 extends between the inner running surface 86 and a location 114 on the conical inner surface 94, wherein the conical projection distance 112 can be the projection distance (e.g., variable distance) at any location along the conical inner surface 94 (e.g., minimum distance, maximum distance, or average distance between minimum and maximum distance). In certain embodiments, the maximum projection distance 106 is less than 20, 30, 40, 50, 60, 70, 80, or 90 micrometers.In certain embodiments, the ratio between the maximum projection spacing 106 and the height of the anti-polishing ring 96 is between 1:400 and 1:190, between 1:390 and 1:200, and / or between 1:380 and 1:210. As will be explained in more detail below, in certain embodiments, the conical projection spacing 112 and / or the maximum projection spacing 106 can vary around the circumferential direction 38 of the anti-polishing ring 84.

[0022] In the illustrated embodiment, the cylinder liner assembly 80 includes one or more fastening elements 116 (e.g., pins, bolts, wedges, threaded fasteners such as threaded screws and / or threaded studs, etc.) configured to couple the anti-polishing ring 84 to the cylinder liner 82. As shown, the cylinder liner 82 is configured to receive the anti-polishing ring 84 in a recess 118 (e.g., an annular recess) of the cylinder liner 82. In the illustrated embodiment, the one or more fastening elements 116 are configured to couple an outer annular surface 120 of the anti-polishing ring 84 to an inner annular recess surface 122 of the recess 118 of the cylinder liner 82.In certain embodiments, the one or more fastening elements 116 can couple a lower annular surface 124 of the anti-polishing ring 84 with an upper annular surface 126 of the recess 118. In certain embodiments, the one or more fastening elements 116 can include an axial wedge (e.g., a rectangular wedge) arranged in a rectangular recess in the inner annular recess surface 122 and in a corresponding rectangular recess in the outer annular surface 120, such that the axial wedge blocks rotation of the anti-polishing ring 84 relative to the cylinder liner 82. The axial wedge and the rectangular recesses can be aligned in an axial direction parallel to the longitudinal center axis 97.In each case, the one or more fastening elements 116 are configured such that they block circumferential rotation 38 of the anti-polishing ring 84 relative to the cylinder liner 82 and / or circumferential rotation 38 of the cylinder liner 82 relative to the anti-polishing ring 84, thereby allowing the conical inner surface 94, the upper inner surface 95, and / or the inner running surface 86 to be contour honed with a single clamp. The anti-polishing ring 84 can be contour honed in place in the cylinder liner 82, so that any desired variation in the cone angle, the projection spacing 16 112, and / or other geometric properties of the surfaces 94, 95, and 86 in the circumferential direction 38 can be made to essentially match the variations in the piston 20 (e.g., variations due to thermal deformation, thrust side and counter-thrust side of the piston 20, etc.).Contour honing can involve an abrasive machining process that produces a precision surface (e.g., circumference, geometry). For example, contour honing can involve rubbing an abrasive (e.g., grinding wheel, grinding disc) against the anti-polishing ring 84 along a controlled path. In certain embodiments, contour honing of the anti-polishing ring 84 can include bore honing, surface honing, trace honing, or a combination thereof.

[0023] In certain embodiments, the anti-polishing ring 84 can be configured such that it can be separated from the cylinder liner 82 (e.g., removed). In certain embodiments, separating the anti-polishing ring 84 from the cylinder liner 82 can allow the piston 82 to be removed from a top surface 127 of the cylinder 26. In certain embodiments, one or more fastening elements 116 can be omitted from the cylinder liner assembly 80, and the cylinder liner 82 and the anti-polishing ring 84 can form a single, continuous piece. That is, the anti-polishing ring 84 and the cylinder liner 82 can form a single, integrally formed structure.It can be acknowledged that hydrocarbon emissions can be reduced as a result of the fact that the anti-polishing ring 84 and the cylinder liner 82 are formed as a single, one-piece molded structure, since there is no gap between the anti-polishing ring 84 and the cylinder liner 82.

[0024] In the illustrated embodiment, the piston 20 has a radius 128 and contains a ring 130 arranged radially in a groove 132 (e.g., an annular groove) of the piston 20. In this embodiment, the ring 130 is an upper ring of the piston 20, and the groove 132 is an upper groove of the piston 20. The piston can, for example, have 2, 3, 4, 5, 6, 7, 8, or more rings 130 and corresponding grooves 132. It should be noted that although the illustrated embodiment shows a single ring 130 and a single groove 132, the piston 20 can contain a plurality of rings 130 arranged in a plurality of grooves 132. As shown, the ring 130 is arranged axially between two webs 133, an upper web 134 of the piston 20 and a lower web 136 of the piston 20. In the illustrated embodiment, the upper web 134 is the upper web 40 (e.g., as in Fig. 2 described) of the piston 20 and the lower web 136 is a second web of the piston 20. Although the illustrated embodiment shows the piston 20 with two webs 133, the piston can have 3, 4, 5, 6, 7, 8 or more webs 133. In certain embodiments, the radius 128 can be greater than 100 millimeters. For example, the radius 128 can be greater than 100, 120, 140, 160, 180 or 200 millimeters. In certain embodiments, the ratio between the maximum projection spacing 106 and the radius 128 of the piston 20 is between 1:5,500 and 1:2,000, between 1:5,000 and 1:2,500 and / or between 1:4,750 and 1:2,700.

[0025] In the illustrated embodiment, the ring 130 projects from an outer radial surface 138 of the piston 20 by a projection distance 140. In certain embodiments, the projection distance 140 can be less than 200 micrometers. For example, the projection distance 140 can be less than 20, 40, 60, 80, 100, 120, 140, 160, 180, or 200 micrometers. A gap 142 between the ring 130 and the lower intersection point 108 has a gap height 144 during a top dead center position of the piston 20. In certain embodiments, the gap height 144 can be less than one or more millimeters. For example, the gap height 144 can be less than 0.5, 0.8, 1.0, 1.2, 1.5, 1.8, 3.0, or 5.0 millimeters. In certain embodiments, the gap height 144 can be in the range of 1.2 to 1.5 millimeters. In certain embodiments, the gap height 144 can be a negative distance.For example, the ring 130 can overlap the conical inner surface 94 by less than 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 millimeters. In the illustrated embodiment, the conical inner surface 94 extends radially over an outer radial circumference 146 of the ring 130. That is, the conical inner surface 94 extends over a radius of the outer radial circumference 146. In certain embodiments, the gap height 144 can be selected such that the possibility of axial movement of the ring 130 over the conical inner surface 94 is avoided or reduced, while the piston 20 (e.g., the upper web 40) moves axially over the conical inner surface 94 at least to the maximum projection distance 106 along the upper inner surface 95. However, if the ring 130 moves axially across the conical inner surface 94, the conical inner surface 94 (e.g.a frustroconical surface) be configured such that it guides the ring 130 and the piston 20 relative to the longitudinal central axis 97 or is self-centered.

[0026] In the illustrated embodiment, the conical inner surface 94 of the conical section 90 is configured such that it projects radially inward from the inner running surface 86 in the direction of the longitudinal center axis 97 and toward the piston 20. Additionally, the upper inner surface 95 of the upper section 88 projects radially inward from the inner running surface 86 in the direction of the longitudinal center axis 97 and toward the piston 20. That is, the conical inner surface 94 and the upper inner surface 95 each project at least partially radially inward relative to the inner running surface 86 of the cylinder liner 82 in the direction of the longitudinal center axis 97 and toward the piston 20. In certain embodiments, the upper inner surface 95 can be omitted.In the illustrated embodiment, the conical projection distance 112, which extends from the inner running surface 86 to a point 114 on the conical inner surface 94, decreases along the downward movement 92 of the piston 20. That is, the maximum projection distance 106 of the anti-polishing ring 84 is located at the upper section 88 of the anti-polishing ring 84. In the illustrated embodiment, the upper section 88 is configured such that it surrounds (e.g., encloses) an outer radial surface 148 of the upper web 134 (e.g., the uppermost piston web) of the piston 20. In certain embodiments, a radial gap 150 (e.g.,an annular or substantially annular gap or clearance extending from the conical inner surface 94 and / or the upper inner surface 95 to the outer radial surface 148 of the piston, is minimized across the outer radial surface 148 of the upper web 134 when the piston 20 is in the top dead center (TDC) position. In the illustrated embodiment, an upper surface 154 of the piston 20 is enclosed by the upper inner surface 95 when the piston 20 is at top dead center. In certain embodiments, the upper surface 154 may be enclosed by the conical inner surface 94 when the piston 20 is at top dead center. In certain embodiments, the upper section 88 of the anti-polishing ring 84 may be omitted. In certain embodiments, the radial gap 150 is relatively small to define a tight clearance between the piston crown and the cylinder liner (TTL).It can be recognized that a TTL profile is a configuration in which the clearance between the upper web 134 and the cylinder liner 82 is reduced in order to decrease the amount of unburned hydrocarbon emissions, including methane (CH4), carbon monoxide (CO) and formaldehyde.

[0027] Fig. Figure 4 is a top view of an embodiment of the piston 20 and the cylinder liner assembly 80. In the illustrated embodiment, the cylinder liner assembly 80 includes the cylinder liner 82, which is directly coupled to the anti-polishing ring 84. As shown, the anti-polishing ring 84 is directly coupled to the cylinder liner 82 via one or more fasteners 116. Although the illustrated embodiment shows one fastener 116, it should be noted that the anti-polishing ring 84 may be coupled to the cylinder liner 82 via two, three, four, five, six, seven, eight, or more fasteners 116. In certain embodiments, the cylinder liner 82 and the anti-polishing ring 84 may be a single piece, and the one or more fasteners 116 may be omitted. As shown, the piston 20 is arranged radially inwards from the cylinder liner 82.

[0028] In the illustrated embodiment, the radial axes 180 and 182 of the piston 20 coincide with the radial axes 184 and 186 of the conical inner surface 94 and / or the upper inner surface 95 of the anti-polishing ring 84, as well as with the radial axes 188 and 190 of the inner running surface 86 of the cylinder liner 82. In certain embodiments, before contour honing of the conical inner surface 94, the upper inner surface 95, and / or the inner running surface 86, the radial axes 184 and 186 may not coincide with the radial axes 188 and 190, respectively. That is, contour honing of the conical inner surface 94, the upper inner surface 95, and / or the inner running surface 86 allows the radial axes 184 and 186 to align with the radial axes 188 and 190, respectively. This means that contour honing can reduce a radial offset (e.g. a disparity) between the conical inner surface 94 and / or the upper inner surface 95 and the inner running surface 86.It should be noted that by contour honing the anti-polishing ring 84 together with the cylinder liner 82 using a single clamp, the concentricity offset between the conical inner surface 94 and / or the upper inner surface 95 and the inner running surface 86 can be significantly reduced.

[0029] In the illustrated embodiment, the radial axes 180 and 182 (e.g., radial axes 184 and 186) intersect the anti-polishing ring 84 at a first angle 192 (e.g., 0 degrees), a second angle 194 (e.g., 90 degrees), a third angle 196 (180 degrees), and a fourth angle 198 (e.g., 270 degrees). As explained in more detail herein, the conical inner surface 94 and / or the upper inner surface 95 of the anti-polishing ring 84 can have different shapes at each circumferential angle 200 (e.g., including the first angle 192, the second angle 194, the third angle 196, and / or the fourth angle 198) of the anti-polishing ring 84.

[0030] Fig. Figure 5 is a partial cross-sectional view of an embodiment of the anti-polishing ring 84, which shows a frustoconic shape. In the illustrated embodiment, the conical inner surface 94 forms an acute angle 210 relative to the axial direction 34 and is located between the upper surface 98 of the anti-polishing ring 84 and the inner running surface 86. As shown, the upper inner surface 95 is omitted from the anti-polishing ring 84. In certain embodiments, the acute angle 210 can be constant in the circumferential direction 38 around the entire circumference of the conical inner surface 94 of the anti-polishing ring 84. In certain embodiments, the acute angle 210 can vary repeatedly and / or non-repeatedly in the circumferential direction 38 around the circumference of the conical inner surface 94. In certain embodiments, during manufacturing, when the motor 10 is not in operation, the acute angle 210 can be adjusted based on expected deformations (e.g.,Thermal deformations) in the cylinder liner 82 and / or the piston 20 vary (e.g., continuously) during operation of the engine 10, the variations being configured to counteract or oppose the expected deformations during operation. In the illustrated embodiment, the acute angle 210 from the inner running surface 86 of the cylinder liner 82 to the upper surface 98 of the anti-polishing ring 84 is constant. In certain embodiments, the shape of the conical inner surface 94 can include a plurality of line segments angled relative to one another. That is, the conical inner surface 94 can have a linear, piecewise shape.

[0031] Fig. Figure 6 is a partial cross-sectional view of an embodiment of the anti-polishing ring 84, which shows a cylindrical and frustoconic shape. In the illustrated embodiment, the conical inner surface 94 forms an acute angle 210 relative to the axial direction 34 and is located between the upper inner surface 95 of the anti-polishing ring 84 and the inner running surface 86. As shown, the upper inner surface 95 of the upper section 88 of the anti-polishing ring 84 forms the cylindrical section of the anti-polishing ring 84. In certain embodiments, the acute angle 210 in the circumferential direction 38 can be constant around the entire circumference of the conical inner surface 94 of the anti-polishing ring 84. In certain embodiments, the acute angle 210 in the circumferential direction 38 can vary repeatedly and / or non-repeatedly around the circumference of the conical inner surface 94.In the illustrated embodiment, the acute angle 210 from the inner running surface 86 of the cylinder liner 82 to the upper inner surface 95 of the anti-polishing ring 84 is constant. In certain embodiments, the shape of the conical inner surface 94 can include a plurality of line segments angled relative to one another. That is, the conical inner surface 94 can have a linear, piecemeal shape. Additionally or alternatively, the height 102 of the upper section can remain constant around the circumferential direction 38 around the entire circumference of the upper section 88, or, in certain embodiments, vary around the circumferential direction 38 around the circumference of the upper section 88. In certain embodiments, during manufacturing, when the engine 10 is not in operation, the conical inner surface 94 (e.g., acute angle 210, shape and / or diameter) and / or the upper inner surface 95 (e.g.,Diameter, shape and / or height 102) vary (e.g., continuously vary) based on expected deformations (e.g., thermal deformations) in the cylinder liner 82 and / or the piston 20 during operation of the engine 10, wherein the variations are configured to counteract or resist the expected deformations during operation.

[0032] Fig. Figure 7 is a partial cross-sectional view of an embodiment of the anti-polishing ring 84, which shows a stepped frustoconic shape. In the illustrated embodiment, the conical inner surface 94 forms an acute angle 210 relative to the axial direction 34 and is located between the upper inner surface 95 of the anti-polishing ring 84 and the inner running surface 86. As shown, the upper inner surface 95 of the upper section 88 of the anti-polishing ring 84 forms the cylindrical section of the anti-polishing ring 84. In certain embodiments, the acute angle 210 in the circumferential direction 38 can be constant around the entire circumference of the conical inner surface 94 of the anti-polishing ring 84. In certain embodiments, the acute angle 210 in the circumferential direction 38 can vary repeatedly and / or non-repeatedly around the circumference of the conical inner surface 94.In the illustrated embodiment, the acute angle 210 from the inner running surface 86 of the cylinder liner 82 to the upper inner surface 95 of the anti-polishing ring 84 is constant. In certain embodiments, the shape of the conical inner surface 94 can include a plurality of line segments angled relative to one another. That is, the conical inner surface 94 can have a linear, piecewise shape. Additionally or alternatively, the height 102 of the upper section can remain constant around the circumferential direction 38 of the upper section 88, or, in certain embodiments, vary around the circumferential direction 38 of the upper section 88.

[0033] In the illustrated embodiment, the anti-polishing ring 84 includes a radial step 230 (e.g., an annular radial lip or an axially directed annular shoulder) that connects the conical inner surface 94 with the inner running surface 86. That is, a lower end 232 of the conical section 90 includes the radial step 230, which is orthogonal to the cylinder liner 82 and extends radially outward from the piston. In certain embodiments, the radial step 230 can be less than 2, 4, 6, 8, 10, or 12 micrometers long. In certain embodiments, the length of the radial step 230 can be constant around the circumferential direction 38 of the anti-polishing ring 84. In certain embodiments, the length of the radial step 230 can vary around the circumferential direction 38 of the anti-polishing ring 84. In certain embodiments, during manufacturing, when the motor 10 is not in operation, the conical inner surface 94 (e.g.acute angle 210, shape and / or diameter), the upper inner surface 95 (e.g. diameter, shape and / or height 102) and / or the radial step 230 vary (e.g. continuously), based on expected deformations (e.g. thermal deformations) in the cylinder liner 82 and / or the piston 20 during operation of the engine 10, wherein the variations are configured to counteract or resist the expected deformations during operation.

[0034] Fig. Figure 8 is a partial cross-sectional view of an embodiment of the anti-polishing ring 84, showing an outwardly curved, ring-shaped form. In the illustrated embodiment, the conical inner surface 94 is curved outwards (e.g., convexly) relative to the anti-polishing ring 84. That is, the conical inner surface 94 bends radially inwards relative to the central axis 97 of the piston 20 (see Figure 8). Fig. 3) As shown, the upper inner surface 95 of the upper section 88 of the anti-polishing ring 84 forms a cylindrical section of the anti-polishing ring 84. In certain embodiments, the curvature of the conical inner surface 94 from the inner running surface 86 to the upper section 88 and / or about the circumferential direction 38 around the entire circumference of the anti-polishing ring 84 can be constant. Additionally or alternatively, the height 102 of the upper section can remain constant about the circumferential direction 38 of the upper section 88, or it can vary about the circumferential direction 38 around the circumference of the upper section 88 in certain embodiments. In certain embodiments, during manufacturing, when the motor 10 is not in operation, the conical inner surface 94 (e.g. radius of curvature and / or shape) and / or the upper inner surface 95 (e.g. diameter, shape and / or height 102) may vary (e.g.continuously varying), based on expected deformations (e.g. thermal deformations) in the cylinder liner 82 and / or the piston 20 during operation of the engine 10, wherein the variations are configured to counteract or resist the expected deformations during operation.

[0035] Fig. Figure 9 is a partial cross-sectional view of an embodiment of the anti-polishing ring 84, showing an inwardly curved, ring-shaped form. In the illustrated embodiment, the conical inner surface 94 is curved inwards (e.g., concave) relative to the anti-polishing ring 84. That is, the conical inner surface 94 bends radially outwards relative to the central axis 97 of the piston 20 (see Figure 9). Fig. 3) As shown, the upper inner surface 95 of the upper section 88 of the anti-polishing ring 84 forms a cylindrical section of the anti-polishing ring 84. In certain embodiments, the curvature of the conical inner surface 94 from the inner running surface 86 to the upper section 88 and / or around the circumferential direction 38 can be constant around the entire circumference of the anti-polishing ring 84. Additionally or alternatively, the height 102 of the upper section can remain constant around the circumferential direction 38 of the upper section 88, or it can vary around the circumferential direction 38 of the circumference of the upper section 88 in certain embodiments. In certain embodiments, during manufacturing, when the motor 10 is not in operation, the conical inner surface 94 (e.g. radius of curvature and / or shape) and / or the upper inner surface 95 (e.g. diameter, shape and / or height 102) may vary (e.g.continuously varying), based on expected deformations (e.g. thermal deformations) in the cylinder liner 82 and / or the piston 20 during operation of the engine 10, wherein the variations are configured to counteract or resist the expected deformations during operation.

[0036] Fig. Figure 10 is a partial cross-sectional view of an embodiment of the anti-polishing ring 84, which shows a complex shape combining aspects from Figures 6, 7, 8, and 9. In the illustrated embodiment, the conical inner surface 94 includes an inwardly curved section 250 (e.g., a concave section) that is curved inward relative to the anti-polishing ring 84. That is, the inwardly (e.g., concave) curved section 250 bends radially outward relative to the central axis 97 of the piston 20 (see Figure 10). Fig. 3) Additionally, the conical inner surface 94 contains an outwardly curved section 252 (e.g., a convexly curved section) which is curved outwards relative to the anti-polishing ring 84. That is, the outwardly (e.g., convexly) curved section 252 bends radially inwards relative to the central axis 97 of the piston 20 (see Fig. 3) As shown, the upper inner surface 95 of the upper section 88 of the anti-polishing ring 84 forms a cylindrical section of the anti-polishing ring 84. In certain embodiments, the curvature of the inwardly curved section 250 and / or the outwardly curved section 252 can be constant from the inner running surface 86 to the upper section 88 and / or around the circumferential direction 38 of an entire circumference of the anti-polishing ring 84. Additionally or alternatively, the height 102 of the upper section can remain constant around the circumferential direction 38 of the upper section 88, or it can vary around the circumferential direction 38 of the circumference of the upper section 88 in certain embodiments.

[0037] In the illustrated embodiment, the anti-polishing ring 84 includes a radial step 230 (e.g., an annular radial lip or an axially directed annular shoulder) that connects the conical inner surface 94 with the inner running surface 86. That is, a lower end 232 of the conical section 90 includes the radial step 230, which is orthogonal to the cylinder liner 82 and extends radially outward from the piston. In certain embodiments, the radial step 230 can be less than 2, 4, 6, 8, 10, or 12 micrometers long. In certain embodiments, the length of the radial step 230 can be constant around the circumferential direction 38 of the anti-polishing ring 84. In certain embodiments, the length of the radial step 230 can vary around the circumferential direction 38 of the anti-polishing ring 84. In certain embodiments, during manufacturing, when the motor 10 is not in operation, the conical inner surface 94 (e.g.radius of curvature, curved inwards, curved outwards, shape, etc.), the upper inner surface 95 (e.g. diameter, shape and / or height 102) and / or the radial step 230 vary (e.g. continuously) based on expected deformations (e.g. thermal deformations) in the cylinder liner 82 and / or the piston 20 during operation of the engine 10, wherein the variations are configured to counteract or resist the expected deformations during operation.

[0038] In certain embodiments, the conical inner surface 94 and / or the upper inner surface 95 of the anti-polishing ring 84 can include any combination of the features described in FIGS. 5-10. In certain embodiments, any combination of the features described in FIGS. 5-10 can be present at different circumferential positions of the anti-polishing ring 84. For example, with reference to Fig. 4 the conical inner surface 94 from the first angle 192 to the second angle 194 frustoconic (e.g. as in Fig. 5 described) be, from the second angle 194 to the third angle 196 stepwise frustoconic (e.g. as in Fig. 7) be curved outwards (e.g., convexly) from the third angle 196 to the fourth angle 198, and inwards (e.g., concavely) from the fourth angle 198 to the first angle 192. In certain embodiments, any combination of the features described in FIGS. 5-10 may be present within a generic (e.g., arbitrary) circumferential sector of the anti-polishing ring 84, i.e., from one circumferential angle 200 to another circumferential angle 200. In certain embodiments, the anti-polishing ring 84 may contain two, three, four, five, six, seven, eight, nine, or more distinct circumferential sectors, each sector having any combination of the features described in FIGS. 5-10.

[0039] Fig. Figure 11 is a graph 268 of the minimum radial projections 270 (e.g., minimum projections for reducing bore polishing) relative to a height from a lower end of the projection 272 for various generic circumferential angles 200 of the anti-polishing ring 84. In the illustrated embodiment, the minimum radial projections 270 for reducing bore polishing are for the first angle 192, the second angle 194, the third angle 196, and the fourth angle 198, as shown in Fig. Figure 4 is shown. As illustrated, Figure 268 of the minimum radial projections 270 contains a variety of drawn lines 271, including a first line 274, a second line 276, a third line 278, and a fourth line 280, corresponding to angles 192, 194, 196, and 198, respectively. As shown, the first line 274, the second line 276, and the fourth line 280 increase in height from the lower end of the projection 272. The minimum radial projection 270 corresponding to angle 196 (e.g., the third line 278) is negative between approximately 3 and 13 millimeters from the lower end of the projection because the piston 20 does not contact the cylinder liner 82 at angle 196, as the piston rod pushes the piston 20 to the opposite side.

[0040] In the illustrated embodiment, the dashed line 282 and the dashed line 284 show two potential shapes of the conical inner surface 94 and / or the upper inner surface 95 of the anti-polishing ring 84. The dashed line 282 corresponds to the one shown in Fig. 5 described frusttoconical form, and the dashed line 284 corresponds to the one in Fig. 6 described cylindrical and frustoconical shapes. In the illustrated embodiment, both the dashed line 282 and the dashed line 284 are close to an upper limit of the plurality of drawn lines 271. It should be noted that while the illustrated embodiment shows two possible shapes of the conical inner surface 94 and / or the upper inner surface 95, other shapes can also be used, which generally lie close to the upper limit of the plurality of drawn lines 271.

[0041] Fig. Figure 12 is a graph 300 of the minimum radial projection 270 for reducing bore polishing with respect to the circumferential angle 200 of the anti-polishing ring. In the illustrated embodiment, the minimum radial projection 270 is represented by a line 302, which may represent empirical data obtained from the cylinder liner 82 using a measuring device. As shown, the line 302 varies irregularly (e.g., non-repeating, unique, uneven, asymmetrical, etc.) with respect to the circumferential angle 200. That is, although the minimum radial projection 270 is not necessarily random, there is no observable pattern in the variation of the minimum radial projection 270.

[0042] In the illustrated embodiment, the dashed line 304 represents a potential irregular shape of the conical inner surface 94 and / or the upper inner surface 95 of the anti-polishing ring 84. In the illustrated embodiment, the dashed line 304 lies close to the drawn line 302. It should be noted that while the illustrated embodiment shows one possible shape of the conical inner surface 94 and / or the upper inner surface 95, other shapes can also be used, which generally lie close to the drawn line 302.

[0043] Fig.Figure 13 is a flowchart of an example process 320 for forming an inner radial surface of the anti-polishing ring 84. The process 320 can be performed by a processor-based computer device or a control system of a manufacturing system, or by any other suitable computer device(s) or control system(s). Furthermore, the blocks of the process 320 can be executed in the sequence disclosed herein or in any other suitable sequence. For example, certain blocks of the process 320 can be executed simultaneously. In addition, in certain embodiments, at least one of the blocks of the process 320 can be omitted.

[0044] In block 322 of process 320, a controller determines a variety of minimum radial protrusion distances of an anti-polishing ring 84 to reduce bore polishing. For example, the controller can run one or more simulations using multi-body dynamics software (e.g., AVL Excite™) to determine the variety of minimum radial protrusion distances to reduce bore polishing relative to an angular position in a circumferential direction of the anti-polishing ring 84.

[0045] In block 324 of process 320, the control determines one or more machining parameters to compensate for the multitude of specified minimum radial protrusion distances. For example, the control can determine an upper limit for the multitude of specified minimum radial protrusion distances and generate an approximation of this upper limit. This approximation of the upper limit can be used to modify one or more machining parameters (e.g., position, orientation, force, etc.) associated with a machining fixture.

[0046] In block 326 of process 320, the controller controls a tool to form the conical inner surface of the anti-polishing ring 84 according to one or more machining parameters. For example, the controller can control the amount of force exerted by the tool according to one or more modified machining parameters. The controller can include one or more control loops (e.g., proportional-integral-differential controller [PID controller]) that drive a measured machining parameter (e.g., measured force) to a setpoint machining parameter (e.g., setpoint force) using one or more feedback loops.

[0047] The technical benefits of the disclosed embodiments include a reduction in the sum of tolerances between the honing surfaces (e.g., conical inner surface, upper inner surface, inner running surface) of the anti-polishing ring and the cylinder liner. By attaching the anti-polishing ring to the cylinder liner, the cylinder liner assembly can be honed in a single liner setup, thereby reducing the concentricity deviation between the anti-polishing ring and the cylinder liner. Furthermore, separating the anti-polishing ring from the cylinder liner allows the piston (e.g., cylinder) to be removed from the cylinder liner from a top-side position, thus providing easier access for maintenance. Additionally, the anti-polishing ring with the projection disclosed herein also reduces bore polishing of the cylinder liner by minimizing the formation of carbon around the piston.Further technical benefits include significantly reduced THC (Total Hydrocarbon) emissions and lower manufacturing costs compared to laser beam welding. The reduced clearance between the piston and anti-polishing ring lowers the overall temperature in and around the piston, as less heat is transferred to the top piston land. This reduced temperature leads to a significant reduction in carbon deposits and the associated failure modes. Finally, the improved oil film viscosity results in less wear on the anti-polishing ring. The reduced temperatures also allow for a further reduction in clearance and emissions by decreasing the height of the top piston land.

[0048] The subject described in detail above can be defined by one or more of the paragraphs listed below.

[0049] From a first perspective, a system includes a cylinder liner assembly configured to line a cylinder around a piston with a tight clearance between the piston crown and the cylinder liner. The cylinder liner assembly comprises a cylinder liner with an inner running surface extending circumferentially around a central axis and an anti-polishing ring.

[0050] The system according to the previous paragraph, wherein the anti-polishing ring includes an upper section extending circumferentially around the central axis and a conical section extending downwards from the upper section along the piston with a narrow clearance between the piston crown and the cylinder liner, wherein the conical section includes a conical inner surface extending circumferentially around the central axis.

[0051] The system according to any previous paragraph, wherein the conical inner surface is configured to project radially inward from the inner running surface, and a projection distance of the conical inner surface extending from the inner running surface to the conical inner surface decreases along the downward direction of the piston with tight clearance between the piston crown and the cylinder liner.

[0052] The system according to any previous paragraph, wherein the upper part is configured to encompass a radial circumference of an upper piston land of the piston with close clearance between the piston head and the cylinder liner in a top dead center (TDC) position of the piston with close clearance between the piston head and the cylinder liner.

[0053] The system according to any previous paragraph, wherein the projection spacing of the conical inner surface varies circumferentially around the anti-polishing ring based on an irregular pattern.

[0054] The system according to any preceding paragraph, wherein the conical inner surface contains an inner radius which varies over a range from a first radius to a second radius, an upper ring of the piston with close clearance between the piston head and the cylinder liner has an outer radius which lies between the first and the second radius of the range, and the upper ring crosses over the conical inner surface when the piston with close clearance between the piston head and the cylinder liner is in a top dead center (TDC) position.

[0055] The system according to any preceding paragraph, wherein the inner running surface is substantially annular, the upper section is substantially annular, and the conical inner surface is substantially annular.

[0056] The system according to any previous paragraph, wherein the cylinder liner and the anti-polishing ring form a single continuous piece.

[0057] The system according to any preceding paragraph, wherein the anti-polishing ring is coupled to the cylinder liner via one or more fastening elements, wherein the one or more fastening elements block rotation of the anti-polishing ring in the circumferential direction relative to the cylinder liner.

[0058] The system according to any preceding paragraph, wherein the anti-polishing ring is configured to be separable from the cylinder liner, and wherein the cylinder liner assembly is configured to allow the piston to be removed from the cylinder liner with tight clearance between the piston crown and the cylinder liner after separation of the anti-polishing ring and the cylinder liner.

[0059] The system according to one of the preceding paragraphs, wherein the conical inner surface of the anti-polishing ring and the inner running surface of the cylinder liner are configured to be contour honed, wherein the anti-polishing ring and the cylinder liner comprise separate parts or a single continuous part.

[0060] The system according to any previous paragraph, wherein the ratio between a maximum projection distance from the inner running surface to the conical inner surface, and an axial length of the anti-polishing ring is between 1:400 and 1:200.

[0061] The system according to any previous paragraph, wherein the upper section contains an upper inner surface extending circumferentially around the central axis, the upper inner surface having a constant radius relative to the central axis in the axial direction along the central axis.

[0062] The system according to any previous paragraph, wherein the ratio between a first axial length of the upper inner surface and a second axial length of the anti-polishing ring is between 1:2 and 3:4.

[0063] The system according to any previous paragraph, wherein a radial distance extending from an inner surface of the anti-polishing ring to an outer surface of the piston with close clearance between the piston head and the cylinder liner is minimal when the piston with close clearance between the piston head and the cylinder liner is in a top dead center (TDC) position.

[0064] According to a second aspect, a system includes a piston with a tight clearance between the piston crown and the cylinder liner. The system further includes a cylinder liner. The cylinder liner contains an anti-polishing ring with a conical section. The conical section is configured to overlap the piston with the tight clearance between the piston crown and the cylinder liner when the piston is in top dead center.

[0065] The system from the previous paragraph, wherein the anti-polishing ring includes an upper section extending circumferentially around a central axis; and the conical section extending from the upper section in a downward direction of the piston, and the conical section having a conical inner surface extending circumferentially around the central axis.

[0066] The system according to any preceding paragraph, wherein the conical inner surface is configured to project radially inward from an inner running surface of the cylinder liner, and wherein a projection distance of the conical inner surface extending from the inner running surface to the conical inner surface decreases along the downward direction of the piston.

[0067] The system according to any previous paragraph, wherein the ratio between a maximum projection distance extending from the inner running surface to the conical inner surface and a piston radius is between 1:4750 and 1:2700.

[0068] According to a third aspect, a method includes providing a cylinder liner with an inner running surface extending circumferentially around a central axis. The method further includes providing an anti-polishing ring, wherein the cylinder liner and the anti-polishing ring are parts of a cylinder liner assembly configured to line a cylinder around a piston with a tight clearance between the piston crown and the cylinder liner.

[0069] This written description uses examples to disclose the invention, including the best embodiment, and to enable any person skilled in the art to apply the invention, including the manufacture and use of any devices or systems and the performance of any methods contained therein. The patentable scope of the invention is defined by the claims and may include further examples encountered by persons skilled in the art. Such further examples fall within the scope of the claims if they have structural elements that do not differ from the wording of the claims or if they contain equivalent structural elements with insignificant differences from the wording of the claims.

Claims

[1] A system, encompassing: a cylinder liner assembly configured to line a cylinder around a piston with a tight clearance between the piston crown and the cylinder liner, the cylinder liner assembly comprising: a cylinder liner comprising an inner running surface extending circumferentially around a central axis; and an anti-polishing ring. [2] The system according to claim 1, wherein the anti-polishing ring comprises: an upper section that extends circumferentially around the central axis; and a conical section extending downwards from the upper section of the piston with a narrow clearance between the piston crown and the cylinder liner, wherein the conical section includes a conical inner surface extending circumferentially around the central axis. [3] The system according to claim 2, wherein the conical inner surface is configured such that it projects radially inwards from the inner running surface, and wherein a projection distance of the conical inner surface, extending from the inner running surface to the conical inner surface, decreases along the downward direction of the piston with close clearance between the piston head and the cylinder liner. [4] The system according to claim 3, wherein the upper section is configured to include a radial circumference of an upper piston land of the piston with close clearance between the piston head and the cylinder liner in a top dead center (TDC) position of the piston with close clearance between the piston head and the cylinder liner. [5] The system according to claim 3, wherein the projection spacing of the conical inner surface varies circumferentially around the anti-polishing ring, based on an irregular pattern. [6] The system according to claim 3, wherein the conical inner surface has an inner radius which varies over a range from a first radius to a second radius, and an upper ring of the piston with close clearance between the piston head and the cylinder liner has an outer radius which lies between the first and the second radius of the range, and the upper ring extends over the conical inner surface when the piston with close clearance between the piston head and the cylinder liner is in a top dead center (TDC) position. [7] The system according to claim 3, wherein the inner running surface is essentially annular, the upper section is essentially annular and the conical inner surface is essentially annular. [8] The system according to claim 3, wherein the cylinder liner and the anti-polishing ring form a single continuous part. [9] The system according to claim 3, wherein the anti-polishing ring is coupled to the cylinder liner via one or more fastening elements, wherein the one or more fastening elements block rotation of the anti-polishing ring in the circumferential direction relative to the cylinder liner. [10] The system according to claim 9, wherein the anti-polishing ring is configured such that it can be separated from the cylinder liner, wherein the cylinder liner assembly is configured such that the piston can be removed from the cylinder liner with a tight clearance between the piston crown and the cylinder liner after separation of the anti-polishing ring and the cylinder liner. [11] The system according to claim 3, wherein the conical inner surface of the anti-polishing ring and the inner running surface of the cylinder liner are configured such that they are contour honed, wherein the anti-polishing ring and the cylinder liner comprise the following: separate parts; or a single, continuous part. [12] The system according to claim 3, wherein the ratio between a maximum projection distance extending from the inner running surface to the conical inner surface and an axial length of the anti-polishing ring is between 1:400 and 1:

200. [13] The system according to claim 3, wherein the upper section comprises an upper inner surface extending circumferentially around the central axis, the upper inner surface having a constant radius relative to the central axis in the axial direction along the central axis. [14] The system according to claim 13, wherein the ratio between a first axial length of the upper inner surface and a second axial length of the anti-polishing ring is between 1:2 and 3:

4. [15] The system according to claim 1, wherein a radial distance extending from an inner surface of the anti-polishing ring to an outer surface of the piston with close clearance between the piston head and the cylinder liner is minimal when the piston with close clearance between the piston head and the cylinder liner is in a top dead center (TDC) position. [16] A system, comprehensive: a piston with a tight clearance between the piston crown and the cylinder liner; and a cylinder liner with an anti-polishing ring having a conical section, wherein the conical section is configured to overlap the piston with a tight clearance between the piston crown and the cylinder liner when the piston is in a top dead center position. [17] The system according to claim 16, wherein the anti-polishing ring comprises: an upper section that extends circumferentially around a central axis; and the conical section extending from the upper section in the downward direction of the piston, wherein the conical section includes a conical inner surface extending circumferentially around the central axis. [18] The system according to claim 17, wherein the conical inner surface is configured such that it projects radially inwards from an inner running surface of the cylinder liner, and wherein a projection distance of the conical inner surface, extending from the inner running surface to the conical inner surface, decreases along the downward direction of the piston. [19] The system according to claim 18, wherein the ratio between a maximum projection distance extending from the inner running surface to the conical inner surface and a piston radius is between 1:4750 and 1:2700. [20] A procedure which includes the following: the provision of a cylinder liner having an inner surface extending circumferentially around a central axis; and the provision of an anti-polishing ring, whereby the cylinder liner and The anti-polishing ring is part of a cylinder liner assembly configured to line a cylinder around a piston with a tight clearance between the piston crown and the cylinder liner.

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