Piston for an internal combustion engine

Abstract

The invention relates to a piston (16) for an internal combustion engine (10), in particular a V-engine. The piston comprises an oil drain groove (54) which is provided in an outer circumferential surface of the piston (16) between a ring belt (26) and a piston skirt (24) of the piston (16), the piston skirt (24) being provided with two recessed pin boss portions (42) on opposite sides of the piston (16), wherein the piston skirt (24) is further provided with at least one oil drain duct (56) which is arranged between the two recessed pin boss portions (42) at an outer surface of the piston skirt (24) and which is configured for fluidically connecting the oil drain groove (54) with the recessed pin boss portions (42).

Description

Technical Field

[0001] The present invention relates to a piston for an internal combustion engine, and an internal combustion engine, particularly a V-type engine, equipped with at least one such piston. Background Technology

[0002] In internal combustion engines such as diesel engines, pistons with a structural configuration including a piston head and a piston skirt are known to be used. The piston head includes an outer annular band on its circumferential outer surface, the outer annular band forming a plurality of circumferentially continuous annular grooves for receiving corresponding piston rings, which abut against the inner wall of the engine cylinder, in which the piston reciprocates during operation.

[0003] Piston rings function to seal the combustion chamber from the engine's crankcase. Furthermore, piston rings are designed to maintain an appropriate amount of oil between the piston and cylinder walls, and regulate engine oil consumption by scraping oil from the cylinder walls back into an oil sump housed in the crankcase.

[0004] Therefore, the lowest annular groove, the one closest to the piston skirt, typically houses a so-called oil scraper ring. This ring is configured to scrape oil from the cylinder wall to limit and regulate the amount of oil delivered to the other piston rings. The purpose of the oil scraper ring is to minimize the so-called "leakage" effect, which causes oil to pass through the piston rings and thus slip into the combustion chamber. Accidental leakage of oil into the combustion chamber is commonly referred to as "lubrication" and can lead to reduced engine performance, reduced engine component life, and unwanted hydrocarbon emissions.

[0005] Specifically, the oil scraper ring is designed so that oil scraped from the cylinder wall accumulates in front of it during the piston's downward stroke. Therefore, to ensure proper functioning of the oil scraper ring, the oil accumulated in front of the ring needs to be adequately drained to ensure a sufficient amount of oil is scraped off the cylinder wall. Thus, known piston configurations include an oil drain path designed to guide and thereby return the oil accumulated in front of the ring to the crankcase during the piston's downward stroke.

[0006] In one known piston configuration, the lowermost groove of the oil scraper ring connects to a limited number of drain holes provided in the piston skirt, and is configured to guide the oil accumulated in the lowermost groove into the interior of the piston skirt. The oil then flows from the interior of the piston skirt back into the crankcase via the bottom of the opening in the piston skirt.

[0007] Furthermore, a piston configuration is known, for example, from US 6,557,514 B1, in which oil accumulating in front of the rings during the piston's downward stroke is received in a circumferential drain groove arranged near the lowermost piston ring groove, and subsequently guided through the outer surface of the piston skirt for discharge into the crankcase. Specifically, the piston skirt has recessed pin seats on opposite sides that lead to the drain groove. With this configuration, oil received in the drain groove is guided through the outer surface of the recessed pin seats to drain downward back into the crankcase.

[0008] However, when a known piston configuration is used in a V-type engine, the piston angle can affect the flow of oil through or across the piston skirt. Thus, the oil to be discharged may encounter increased flow resistance as it flows through the return path formed by the piston, for example, due to oil splashing or upward deflection against gravity. As a result, a sufficiently high return flow velocity from the piston rings to the piston skirt cannot be guaranteed, which may cause oil to slip into the combustion chamber during operation. Summary of the Invention

[0009] Based on existing technology, the object of the present invention is to provide an improved piston for an internal combustion engine that effectively prevents oil from slipping into the engine's combustion chamber, particularly when applied to a V-type engine. To this end, one object is to provide an internal combustion engine, particularly a V-type engine, equipped with at least one such piston.

[0010] These objectives are achieved through the subject matter of the independent claims. Preferred embodiments are set forth in this specification, the accompanying drawings, and the dependent claims.

[0011] Therefore, a piston for an internal combustion engine, particularly a V-type engine, is provided, the piston including an oil drain groove provided in the outer circumferential surface of the piston between the piston ring and the piston skirt. The piston skirt has two recessed pin seat portions on opposite sides of the piston, and at least one oil drain pipe disposed between the two recessed pin seat portions is provided on the outer surface of the piston skirt. The oil drain pipe is configured to fluidly connect the oil drain groove and the recessed pin seat portions.

[0012] In addition, an internal combustion engine, particularly a V-type engine, equipped with at least one of the aforementioned pistons is provided. Attached Figure Description

[0013] The invention will be more readily understood by referring to the following detailed description when considered in conjunction with the accompanying drawings, wherein:

[0014] Figure 1 A schematic cross-section of an internal combustion engine is shown;

[0015] Figure 2 It shows Figure 1An enlarged view of the internal combustion engine shown;

[0016] Figure 3 It shows the use of Figure 1 and 2 A schematic front view of the piston in the engine shown;

[0017] Figure 4 It shows Figure 3 A schematic side view of the piston shown;

[0018] Figure 5 A schematic perspective view of a piston according to another configuration is shown; and

[0019] Figure 6 It shows Figure 5 Another schematic perspective view of the piston shown. Detailed Implementation

[0020] The invention will be explained in more detail below with reference to the accompanying drawings. In the drawings, the same elements are indicated by the same reference numerals, and repeated descriptions may be omitted to avoid redundancy.

[0021] Figure 1 An internal combustion engine 10, also referred to hereinafter as an "engine," is schematically shown, which can be installed as a main engine or auxiliary engine in a vehicle such as a ship or construction vehicle. In the illustrated configuration, the engine 10 is provided as a V-type engine comprising a plurality of cylinders 12 arranged in a V-configuration, such as eight, twelve, or eighteen cylinders. Specifically, as Figure 1 As shown, cylinders 12 are arranged in two rows parallel to the crankshaft 14 of engine 10. Each row of cylinders 12 is also referred to as a cylinder bank. The angle between cylinder banks (also referred to as the "bank angle") is 40° in the illustrated configuration, but is not limited to this. Instead, engine 10 can be provided with any suitable bank angle, such as a bank angle between 20° and 120°, and particularly 50°.

[0022] Each cylinder 12 houses a piston 16 having a head portion that defines a combustion chamber 18 within the cylinder 12. Specifically, the piston 16 is configured to reciprocate and move axially within the cylinder 12 and is connected to the crankshaft 14 of the engine 10 via a connecting rod 20.

[0023] The engine 10 also includes: a control device (not shown) for controlling the actuation of an intake system (not shown) for selectively supplying an air-fuel mixture to the combustion chamber 18; an ignition system (not shown) for selectively igniting the air-fuel mixture received in the combustion chamber 18; and an exhaust system (not shown) for selectively exhausting combustion gases from the combustion chamber 18.

[0024] In this configuration, when the air-fuel mixture is ignited in the combustion chamber 18, high-temperature and high-pressure gases are generated in the combustion chamber 18. These gases exert a force on the piston 16 and thus move the piston 16 axially, thereby rotating the crankshaft 18. In this way, chemical energy is converted into mechanical energy.

[0025] The basic structure and operating mode of the engine 10 and its components are well known to those skilled in the art and therefore will not be described further. Instead, the features of the piston 16 used in the engine 10 interconnected with the present invention are described below.

[0026] Figure 2 An enlarged view of the piston 16 in its installed state is shown, i.e., the piston is mounted in the cylinder 12 of the engine 10. For this purpose, Figure 3 and 4 It shows Figure 1 and 2 The piston 16 shown is in an uninstalled state, i.e., the piston 16 is removed from the engine 10.

[0027] The piston 16 preferably has a multi-part design, such as a two-part design, wherein the piston head 22 and the piston skirt 24 constitute different parts of the piston 16. Alternatively, the piston 16 may be provided with an integral design, also referred to as an integral structure or integral piston, wherein the piston 16 is cast from a single piece.

[0028] The piston head 22 has a cylindrical annular band 26 on its outer circumferential surface. The annular band 26 is spaced apart from the front end of the piston head 22, which defines the combustion chamber 18 of the cylinder 12. The annular band 26 has a plurality of piston ring grooves 28, 30, and 32 formed on its outer surface, such as… Figure 2 As shown, each piston ring groove is designed to accommodate piston rings 34, 36, and 38, which are also referred to as oil guard rings. Specifically, piston rings 34-38 are configured to seal and separate the combustion chamber 18 from the crankcase of the engine 10, while maintaining an appropriate amount of oil between the piston 16 and the cylinder wall 40 during the operation of the engine 10. To this end, piston rings 34-38 limit and regulate engine oil consumption by scraping oil from the cylinder wall 40 back into an oil groove housed in the crankcase, as will be explained below.

[0029] Specifically, for this purpose, the lowermost piston ring 38, that is, the piston ring housed in the lowermost ring groove 32, is provided in the form of a so-called oil scraper ring. With this configuration, the piston ring 38 housed in the lowermost ring groove 32 is configured to scrape oil from the cylinder wall 40 when the piston 16 moves in the downward stroke within the cylinder 12.

[0030] In the context of this invention, the term "lowest piston ring" 38 refers to the piston ring among the plurality of piston rings 34-38 that is arranged closest to the piston skirt 24.

[0031] The piston head 22 is also equipped with an internal cooling channel (not shown) in which cooling oil circulates to cool the piston 16, i.e., its head portion, during operation. The basic structure and operation of such an internal cooling channel are well known to those skilled in the art and therefore will not be described further.

[0032] The piston skirt 24 includes two recessed pin seat portions 42 arranged on opposite sides of the piston skirt 24. In other words, the pin seat portions 42 are arranged opposite to each other with respect to the longitudinal axis L of the piston 16.

[0033] In the context of this invention, the term "longitudinal axis" L refers to the axis of piston 16, which is parallel to the direction of reciprocating movement of piston within cylinder 12.

[0034] Each recessed pin seat portion 42 is provided with a pin seat 44, in which a toggle pin 46 for pivotally connecting the piston 16 to the connecting rod 20 is received. In this configuration, the toggle pin 46 extends through the interior of the piston skirt 24 and engages with a pin bore 48 formed in the pin seat 44. Therefore, the pin bore 48 is aligned along the piston's pin bore axis P.

[0035] In the context of this invention, the term "pin hole axis" P refers to the axis of piston 16 that is perpendicular to the longitudinal axis L of piston 16 and parallel to the longitudinal axis of toggle pin 46.

[0036] In the configuration shown, the recessed pin seat portion 42 is arranged adjacent to the cylindrical portion 50 of the piston skirt 24. The recessed pin seat portion 42 and the cylindrical portion 50 together form the housing surface of the piston skirt 24, i.e., the outer surface.

[0037] More specifically, the piston skirt 24 is configured such that, in the mounted state of the piston 16, the outer surface of the cylindrical portion 50 of the piston skirt 24 is arranged adjacent to and substantially follows the shape of the cylinder wall 40, wherein the outer surface 52 of the recessed pin seat portion 42 is spaced apart from the cylinder wall 40. In other words, in the region of the pin seat portion 42, a portion of the housing surface of the piston skirt 24 is intentionally recessed compared to the cylindrical housing surface, while another portion of the piston skirt housing surface formed by the cylindrical portion 50 is designed to substantially follow the cylindrical housing surface. Thus, when received within the cylinder 12, a gap is formed between the recessed pin seat portion 42 and the cylinder wall 40, i.e., in the radial direction, which is substantially larger than the gap formed between the cylindrical portion 50 of the piston skirt 24 and the cylinder wall 40.

[0038] exist Figures 1 to 4In the configuration of piston 16 shown, the outer surface 52 of the recessed pin seat portion 42 forming the outer surface of piston 16 has a planar shape. Alternatively, the outer surface 52, particularly in the region surrounding the pin hole 48, may be provided with a plurality of recesses extending in the radially inward direction, such as... Figure 5 and 6 A further configuration of the piston 16 shown is illustrated.

[0039] Furthermore, the piston 16 includes an oil drain groove 54 disposed on the outer circumferential surface of the piston between the annular belt 26 and the piston skirt 24 of the piston 16. In the illustrated configuration, the oil drain groove 54 forms a circumferentially continuous annular groove in the outer surface (i.e., the housing surface) of the piston 24. The oil drain groove 54 separates the piston head 22 and the piston skirt 24 from each other. In other words, in the downward or retrograde stroke direction of the piston 26, i.e., along the longitudinal axis L, the annular belt 26, the oil drain groove 54, and the piston skirt 24 are arranged successively, i.e., one after another.

[0040] In the context of this invention, the term "downward or descending stroke direction of movement" for piston 16 refers to the direction of movement of piston 16 along its longitudinal axis L, which, in the mounted state of piston 16, faces crankshaft 14 or crankcase of engine 10.

[0041] The oil drain groove 54 is configured to receive and collect oil that accumulates in front of or in front of the annular ring 26 during the operation of the piston 16. Essentially, as described above, the lowermost piston ring 38, housed in the lowermost annular groove 32, is configured to scrape oil from the cylinder wall 40 as the piston 16 moves downwards within the cylinder 12 during the downward stroke. In other words, as the piston 16 moves axially downwards within the cylinder 12, i.e., in the downward stroke direction, the lowermost annular groove 32 scrapes oil from the cylinder wall 40, and the oil is then collected in the oil drain groove 54.

[0042] Furthermore, the piston 16 includes two drain pipes 56 designed and configured to drain oil collected in the drain groove 54 into the crankcase. Specifically, the piston skirt 24 has drain pipes 56 on its outer surface, such that each drain pipe 56 is arranged between recessed pin seat portions 42. In other words, in the circumferential direction of the piston 16, i.e., around its longitudinal axis L, each drain pipe 56 is arranged between the recessed pin seat portions 42. The drain pipes 56 are configured to fluidly connect the drain groove 54 and the recessed pin seat portions 42. More specifically, the drain pipes 56 are designed and configured to guide oil received in the drain groove 54 toward the recessed pin seat portions 42, i.e., the gap formed between the recessed pin seat portions 42 and the cylinder wall 40, when the piston 16 is actuated. In other words, the drain pipe 56 is configured and designed to guide the oil collected in the drain trough 54 through the drain pipe 56 and then drain the oil from the drain trough 54 to the crankcase of the engine 10 along the outside 52 of the recessed pin seat portion 42 before draining it into the crankcase.

[0043] By incorporating the drain pipe 56, the proposed piston 16 ensures that the flow cross-section for draining the oil collected before the ring 26 into the crankcase is sufficiently high along the entire flow path to ensure proper oil removal from the ring 24. This prevents the oil collected before the ring 26 from experiencing high flow resistance, thus avoiding undue pressure that could cause oil to slip into the combustion chamber 18.

[0044] exist Figures 1 to 6 In both configurations of the piston 16 shown, the piston 16 includes two drain pipes 56 disposed between two recessed pin seat portions 42. Alternatively, the piston 16 may include more or fewer than two drain pipes 56. Alternatively or additionally, the drain pipes 56 shown may be separated, such that each drain pipe 56 is divided into two distinct drain pipes, which may be spaced apart from each other along the circumferential direction of the piston 16.

[0045] like Figure 2 As shown, two oil drain pipes 56 are arranged on opposite sides of the piston 16. Specifically, the two oil drain pipes 56 are arranged opposite each other with respect to the longitudinal axis L and the pin hole axis P of the piston 16.

[0046] Each drain pipe 56 is formed by a groove provided on the outer surface of the piston skirt 24. In other words, the drain pipe 56 is machined (in particular cut) into the outer surface of the piston skirt 24, and in particular into the cylindrical portion 50 arranged adjacent to the recessed pin seat portion 42 of the piston skirt 24.

[0047] The oil drain pipe 56 is designed so that its flow cross-section gradually tapers along the flow direction of the oil in the drain pipe 56. Figures 2 to 6 In the diagram, the flow direction of the oil guided through the drain pipe 56 is indicated by arrow A. As can be seen from the flow direction shown, the flow path of the oil guided through the drain pipe 56 smoothly deflects downwards, i.e., in the direction of downward movement.

[0048] In essence, in the proposed piston 16 configuration, the flow direction of oil to be discharged along the outer surface of the piston skirt is smoothly deflected downwards as it flows through the drain pipe 56. Specifically, by arranging the drain pipe 56 between the recessed pin seat portions 42, the drain pipe 56 is provided with a certain length that helps to smoothly deflect the oil flow as it flows through the drain pipe 56, thereby improving the return flow, especially when the piston 16 is used in a V-type engine.

[0049] Specifically, in order to ensure the proper length of the drain pipe 56, the drain pipe 56 extends along the entire circumference of the cylindrical portion 50 of the piston skirt 24.

[0050] The structural arrangement and features of the drain pipe 56 are further described in detail below.

[0051] like Figures 2 to 4 As shown, each drain pipe 56 includes a bottom edge 58 disposed on the outer surface of the piston skirt 24. The bottom edge 58 extends between two recessed pin seat portions 42, such that its associated drain pipe 56 leads to the recessed pin seat portions 42. Figure 2 As can be seen, the bottom edge 58 is designed such that in the direction of oil flow guided through the drain pipe 56, the bottom edge 58 bends downward, that is, bends smoothly, that is, bends in the downward movement direction.

[0052] Specifically, such as Figure 3 and 4 As shown, the drain pipe 56 is designed such that, in the downward direction of movement, i.e., parallel to the longitudinal axis L of the piston 16 and pointing towards the crankshaft 14, the middle section 60 of the bottom edge 58 is positioned before the two opposite end sections 62 of the bottom edge 58. In other words, when viewed in the downward direction of movement, the middle section 60 is positioned before the two opposite end sections.

[0053] More specifically, such as Figure 2 As shown, each drain pipe 56 is designed such that, with the piston 16 installed in the engine 10, when viewed downwards along the vertical axis Z of the engine 10, the middle section 60 of the bottom edge 58 is positioned before the two opposing end sections 62 of the bottom edge 58. In other words, the drain pipe 56 is designed such that, with the piston 16 installed in the engine 10, the end sections 62 of the bottom edge 58 are positioned below the middle section 60 of the bottom edge 58. To illustrate this structural arrangement, in Figure 2 The horizontal plane H is represented by a dashed line.

[0054] Alternatively, the drain pipe 56 may be designed such that, when viewed in a downward direction along the vertical axis Z of the engine 10, the middle section 60 of the bottom edge 58 is positioned at the same level as the two opposite end sections 62 of the bottom edge 58. Furthermore, in the installed state, each drain pipe 56 is designed such that its bottom edge 58 bends downward relative to the horizontal plane H. Alternatively, the drain pipe 56 may be designed such that its bottom edge 58 extends parallel to the horizontal plane H.

[0055] By setting the oil drain pipe 56, the proposed piston configuration takes into account the structural arrangement and installation conditions of the piston 16 in a V-type engine. Specifically, even if the piston 16 is arranged at an angle relative to the vertical axis Z of the engine 10, i.e. due to the exhaust angle of the V-type engine, the proposed oil drain pipe 56 can prevent the oil drained from the oil drain groove 54 into the crankcase from being deflected upward by the bottom edge 58 when it is guided over the outer surface of the piston skirt 24, i.e., deflected upward against gravity.

[0056] As described above, in an alternative configuration, each drain pipe 56 can be separate or divided into two distinct drain pipes. In this configuration, the drain pipe can have a bottom edge having a first end section leading to a recessed pin seat portion 42 and a second end section leading to a drain groove 54. In this configuration, the technical features described in connection with the intermediate section 60 (particularly regarding the structural arrangement) can be applied to and are therefore disclosed for both the inner and outer ends. Therefore, the technical features described above in connection with the end section 62 can be applied to and are therefore disclosed for the second end section.

[0057] Furthermore, each drain pipe 56 includes two opposing side edges 64, which, together with the bottom edge 58, define the flow path of oil through the drain pipe 56. The lateral edges 64 are arranged on the outer surface of the piston skirt 24. Specifically, each side edge 64 extends along the longitudinal axis L of the piston 16 between one of the drain groove 54 and the recessed pin seat portion 42. Thus, the flow cross-section of the drain pipe 56 gradually decreases in the flow direction A of the oil through the drain pipe 56.

[0058] In the configuration shown, the bottom edge 58 has a parabolic shape. Alternatively, the bottom edge 58 can have a clamping shape. For this purpose, the bottom edge 58 can be arranged entirely within a plane.

[0059] Specifically, the shape of the bottom edge 58 of the oil drain pipe 64 is parameterized by the following equation:

[0060] x = r × cos(t),

[0061] y = r × sin(t),

[0062] z = b + c × (r × - |cos(t)) 2 |),

[0063] for

[0064] Where x represents the position along the pin seat axis P; y represents the position along the transverse axis that runs through the pin seat axis P; z represents the position along the central longitudinal axis L of the piston 16, which is transverse to the pin seat axis P and the transverse axis; r represents the radius of the outer circumferential surface of the piston skirt (i.e., the cylindrical portion 50) around the central longitudinal axis L of the piston 16; b is a parameter indicating the height position of the middle section 60 of the bottom edge 58 relative to the pin seat axis P; and c represents a coefficient.

[0065] It will be apparent to those skilled in the art that these embodiments and items merely illustrate numerous possibilities. Therefore, the embodiments shown herein should not be construed as limiting these features and configurations. Any possible combination and configuration of the features may be selected according to the scope of the invention.

[0066] This is particularly relevant to the case of the following optional features, which can be combined with some or all of the previously mentioned embodiments, items and / or features in any technically feasible combination.

[0067] A piston for an internal combustion engine (particularly a V-type engine) may be provided, the piston including an oil drain groove disposed in the outer circumferential surface of the piston between the piston ring and the piston skirt, the piston skirt having two recessed pin seat portions on opposite sides of the piston, wherein the piston skirt is also provided with at least one oil drain pipe disposed between the two recessed pin seat portions on the outer surface of the piston skirt and configured to fluidly connect the oil drain groove and the recessed pin seat portions.

[0068] In other words, with this configuration, the proposed drain pipe is preferably configured to guide oil through the drain pipe when the piston is operating in the engine and then drain the oil from the drain groove into the engine crankcase along the outside of the recessed pin seat portion.

[0069] By configuring the suggested drain pipe, it can be ensured that oil is properly returned from the ring belt to the crankcase. Specifically, the proposed configuration allows for a sufficient length of drain pipe to define the flow path for the oil, such that the flow path is subject to relatively low flow resistance as the oil flows through the drain pipe, for example, by reducing oil splashing or preventing the oil from being deflected upwards against gravity.

[0070] The proposed piston is intended and configured for use in any suitable internal combustion engine, particularly a reciprocating engine, which serves as the main or auxiliary engine in a vehicle, ship, or power plant. Specifically, the proposed piston can be used in a V-type engine, but is not limited to this application. Such an engine can operate on liquid fuels (such as diesel or gasoline) or gaseous fuels.

[0071] The proposed piston can be provided in a multi-part design, such as a two-part design, where the piston head and piston skirt that house the annulus band constitute different parts. Alternatively, the piston can be provided in a single-piece design, where the piston is cast as a single unit.

[0072] As described above, the piston skirt includes recessed pin seat portions disposed on opposite sides of the piston skirt. Therefore, the recessed pin seat portions form the housing surface of the piston skirt. Furthermore, the piston skirt includes two opposing cylindrical portions, each disposed adjacent to and between the recessed pin seat portions. When comparing the recessed pin seat portions and the cylindrical portions of the piston skirt, the diameter of the piston extending between the recessed pin seat portions (i.e., transverse to its longitudinal axis) is smaller than the diameter extending between the cylindrical portions. Thus, when received in the engine cylinder, a gap is formed between the pin seat portions and the cylinder wall, into which the drain pipe opens, and the oil flowing through the drain pipe is guided through this gap to the engine crankcase.

[0073] Specifically, the outer surface of the pin seat portion forming the outer surface of the piston skirt can have a planar shape. Alternatively or additionally, the outer surface of these pin seat portions can be configured such that it does not extend beyond the plane in the radial direction of the piston (i.e., across its longitudinal axis), i.e., the plane can be arranged parallel to the longitudinal axis and can be an imaginary plane. In this configuration, the outer surface can be provided with one or more grooves extending in a direction opposite to the radial direction of the piston.

[0074] The piston skirt may be provided with at least one drain pipe. In a further development, the piston skirt may be provided with at least two drain pipes, which are arranged between the two recessed pin seat portions on opposite sides of the piston.

[0075] Specifically, the at least one oil drain pipe can be formed by a recess provided in the outer surface of the piston skirt. In other words, at least one oil drain pipe can cut into the outer surface of the piston skirt.

[0076] In further development, the drain pipe can be designed such that when the piston is mounted in the engine and operating in the engine, the flow cross section of the drain pipe decreases along the direction of oil flow in the drain pipe.

[0077] Furthermore, the drain pipe may include a bottom edge disposed on the outer surface of the piston skirt and extending between the two recessed pin portions, such that the drain pipe leads to at least one of the two recessed pin portions.

[0078] For example, the drain pipe can be designed such that, in the downward direction of piston movement along the piston's longitudinal axis, the middle section of the bottom edge is positioned before or at the same level as the two opposite end sections of the bottom edge.

[0079] In further development, with the piston installed in the engine (especially in a V-type engine), the drain pipe can be designed such that, in the downward direction along the vertical axis of the engine, the middle section of the bottom edge is arranged before or at the same level as the two opposite end sections of the bottom edge.

[0080] Additionally or alternatively, in the piston mounting configuration of an engine (particularly in a V-type engine), the drain pipe may be designed such that its bottom edge bends downward or extends parallel to the horizontal plane relative to the middle section extending through the bottom edge.

[0081] In a further development, the drain pipe may further include two opposing lateral edges arranged on the outer surface of the piston skirt, each extending along the longitudinal axis of the piston between the drain groove and one of the recessed pin seats.

[0082] Additionally or alternatively, the bottom edge of the drain pipe may have a parabolic or clamp shape.

[0083] Specifically, the shape of the bottom edge of the drain pipe can be parameterized at least in part by the following:

[0084] x = r × cos(t),

[0085] y = r × sin(t),

[0086] z = b + c × (r × - |cos(t)) i |),

[0087] for

[0088] Where x represents the position along the pin seat axis; y represents the position along the transverse axis traversing the pin housing axis; z represents the position along the central longitudinal axis of the piston; r represents the radius of the outer circumferential surface of the piston skirt around the central longitudinal axis of the piston; b is a parameter indicating the height position of the middle section of the bottom edge relative to the pin seat axis; c represents a coefficient; and i represents an exponent provided as a natural number. Specifically, the exponent i can be 2, or any other suitable value, such as between 1 and 8, like 3 or 4.

[0089] In addition, an internal combustion engine, particularly a V-type engine, can be provided, which includes at least one piston as described above.

[0090] Since the proposed internal combustion engine is equipped with the piston described above, the technical features described in conjunction with the piston can also be applied to the proposed internal combustion engine, and vice versa.

[0091] Industrial applicability

[0092] Referring to the accompanying drawings and description, a piston for an internal combustion engine and an internal combustion engine equipped with such a piston, particularly a V-type engine, are proposed. The proposed piston can replace conventional pistons and can be used as a replacement or improvement component.

Claims

1. A piston for an internal combustion engine (10) comprising an oil drain groove (54) disposed in the outer circumferential surface of the piston (16) between an annular band (26) and a piston skirt (24), wherein the piston skirt (24) has two recessed pin seat portions (42) on opposite sides of the piston (16), wherein The piston skirt (24) is further provided with at least one oil drain pipe (56), which is arranged between the two recessed pin seat portions (42) on the outer surface of the piston skirt (24) and configured to fluidly connect the oil drain groove (54) to the recessed pin seat portions (42). The oil drain pipe (56) is designed such that when the piston (16) is installed in the engine (10) and is operating in the engine (10), the flow cross section of the oil drain pipe (56) decreases along the flow direction (A) of the oil in the oil drain pipe (56).

2. The piston according to claim 1 has a multi-part design, wherein the piston head (22) and the piston skirt (24) constitute different parts.

3. The piston according to claim 1 or 2, wherein the recessed pin portion (42) has a flat outer surface (52) forming the outer surface of the piston (16).

4. The piston according to any one of claims 1 to 3, wherein the drain pipe (56) is configured to, when the piston (16) is operating in the engine (10), guide oil through the drain pipe (56) and subsequently drain oil from the drain groove (54) into the crankcase of the engine (10) along the outside (52) of the recessed pin seat portion (42).

5. The piston according to any one of claims 1 to 4, wherein the piston comprises at least two drain pipes (56) arranged on opposite sides of the piston (16) between the two recessed pin portions (42).

6. The piston according to any one of claims 1 to 5, wherein the oil drain pipe (56) is formed by a groove provided in the outer surface of the piston skirt (24).

7. The piston according to any one of claims 1 to 6, wherein the drain pipe (56) includes a bottom edge (58) disposed on the outer surface of the piston skirt (24) and extending between the two recessed pin portions (42), such that the drain pipe (56) leads to at least one of the two recessed pin portions (42).

8. The piston according to claim 7, wherein the drain pipe (56) is designed such that, in the downward direction of the piston (16) along the longitudinal axis (L) of the piston (16), the middle section (60) of the bottom edge (58) is arranged before or at the same level as the two opposite end sections (62) of the bottom edge (58).

9. The piston according to claim 8, wherein, in the installed state of the piston (16) in the engine (10), the drain pipe (56) is designed such that, in a direction downward along the vertical axis (Z) of the engine (10), the middle section (60) of the bottom edge (58) is arranged before or at the same level as the two opposite end sections (62) of the bottom edge (58).

10. The piston according to claim 8 or 9, wherein, in the installed state of the piston (16) in the engine (10), the drain pipe (56) is designed such that its bottom edge (58) bends downward or extends parallel to the horizontal plane (H) of the intermediate section (60) extending through the bottom edge (58).

11. The piston according to claim 8, wherein the drain pipe (56) further comprises two opposing lateral edges (64) disposed on the outer surface of the piston skirt (24), each of the lateral edges extending along the longitudinal axis (L) of the piston (16) between one of the drain groove (54) and the recessed pin portion (42).

12. The piston according to any one of claims 8 to 11, wherein the bottom edge (58) of the oil drain pipe (56) has a parabolic or clamp shape.

13. The piston according to claim 12, wherein the shape of the bottom edge (58) of the oil drain pipe (56) is at least partially parameterized by the following: x = r × cos(t), y = r × sin(t), z=b+c×(r×-|cos(t) i |) for Where x represents the position along the pin axis (P) of the piston (16); y represents the position along the transverse axis that runs through the pin axis (P); z represents the position along the central longitudinal axis (L) of the piston (16); r represents the radius of the outer circumferential surface of the piston skirt (24) around the central longitudinal axis (L) of the piston; b is a parameter indicating the height position of the middle section (60) of the bottom edge (58) relative to the pin axis (P); c represents a coefficient; and i represents an exponent provided as a natural number.

14. The piston according to claim 1, wherein the internal combustion engine (10) is a V-type engine.

15. An internal combustion engine (10) comprising at least one piston (16) according to any one of claims 1 to 14.

16. The internal combustion engine (10) according to claim 15, wherein the internal combustion engine (10) is a V-type engine.

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