An oil control ring foran engine piston, and a piston assembly for an engine cylinder

Abstract

An oil control ring for an engine piston includes a control ring core having a substantially circular shape. An outer surface of the control ring core has a control ring core outer circumference and a first rail having a first width. The first rail is disposed about the control ring core outer circumference. A second rail has a second width. The second rail is disposed about the control ring core outer circumference, and the second rail is positioned at a distance from the first rail.

Description

AN OIL CONTROL RING FORAN ENGINE PISTON, AND A PISTON ASSEMBLY FOR AN ENGINE CYLINDERCROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to and the benefit of Indian Provisional Patent No. 202441058438, filed August 1, 2024, the entire disclosure of which is hereby incorporated by reference herein.TECHNICAL FIELD

[0002] The present application relates generally to systems for controlling oil during piston movement in an engine system.BACKGROUND

[0003] In an engine system, a piston moves within a cylinder. Piston rings on the piston scrape oil from the cylinder wall during piston movement. Excess oil is returned to the engine system.SUMMARY

[0004] In one set of embodiments, an oil control ring for an engine piston includes a control ring core having a substantially circular shape. An outer surface of the control ring core has a control ring core outer circumference and a first rail having a first width. The first rail is disposed about the control ring core outer circumference. A second rail has a second width. The second rail is disposed about the control ring core outer circumference, and the second rail is positioned at a distance from the first rail.

[0005] In another set of embodiments, a piston assembly for an engine cylinder includes a piston having a piston outer circumference, and the oil control ring coupled to the piston. The oil control ring includes the first rail having a first width and the second rail having a second width. The first rail and the second rail are disposed about the piston outer circumference and positioned between the piston and the engine cylinder.

[0006] In another embodiment, an oil control ring for an engine piston includes a rail ring defining an inner curved surface. The rail ring includes a first rail having a first width, and a second rail having a second width being different than the first width. The second rail is positioned at a distance from the first rail. The oil control ring also includes a control ring core coupled to the inner curved surface.BRIEF DESCRIPTION OF THE FIGURES

[0007] The details of one or more implementations are set forth in the accompanying drawing and the description below. Other features, aspects, and advantages of the disclosure will become apparent from the description, the drawing, and the claims, in which:

[0008] Figure 1 is a schematic representation of an example engine system; and

[0009] Figure 2 is a cross-sectional view of a portion of a piston assembly for an engine cylinder.

[0010] It will be recognized that the Figure is a schematic representation for purposes of illustration. The Figure is provided for the purpose of illustrating one or more implementations with the explicit understanding that the Figure will not be used to limit the scope or the meaning of the claims.DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

[0011] An example internal combustion engine system (e.g., an engine system 10, etc.) is configured to combust a fuel (e.g., diesel fuel, gasoline, etc.) to produce energy that may be utilized by various outputs. For example, the internal combustion engine system may produce energy that is utilized to drive a movement member (e.g., wheel, tread, propeller, impeller, turbine, rotor, etc.) or power a generator. The internal combustion engine system may be, for example, a diesel internal combustion engine system, a gasoline internal combustion engine system, a hybrid internal combustion engine system, a hydrogen engine system, etc.

[0012] As schematically represented in Figure 1, the engine system 10 includes a cylinder block 30 and a cylinder head 40. The cylinder head 30 is coupled to the cylinder block 30. The cylinder block 30 houses engine cylinders 50 for the internal combustion engine 20. The enginesystem 10 includes one or more engine cylinders 50. The number of engine cylinders 50 may vary depending upon the particular engine arrangement (e.g., two engine cylinders, four engine cylinders, five engine cylinders, six engine cylinders, seven engine cylinders, eight engine cylinders, nine engine cylinders, ten engine cylinders, twelve engine cylinders, fourteen engine cylinders, etc.).

[0013] The engine system 10 also includes one or more pistons contained within the one or more engine cylinders 50. The pistons move upwards and downwards within the engine cylinders to transfer force from expanding gas (e.g., fluid, etc.) in the engine cylinders 50 to a crankshaft via a piston rod. A combustion chamber is positioned within the engine cylinder 50 between a top portion of the piston and a top portion of the engine cylinder 50. Each of the pistons also include piston rings of various functions that create a gas-tight seal with each of the engine cylinders.

[0014] As shown in Figure 2, an oil control ring 100 for an engine piston includes a control ring core 108 having a substantially circular shape. An outer surface of the control ring core 108 has a control ring core outer circumference and a first rail 114 having a first width. The first rail 114 is disposed about the control ring core outer circumference. A second rail 116 has a second width. The second rail 116 is disposed about the control ring core outer circumference, and the second rail 116 is positioned at a distance from the first rail 114.

[0015] A piston assembly 101 for an engine cylinder includes a piston 103 having a piston outer circumference, and the oil control ring 100 coupled to the piston 103. The oil control ring 100 includes the first rail 114 having a first width and the second rail 116 having a second width. The first rail 114 and the second rail 116 are disposed about the piston outer circumference and positioned between the piston 103 and the engine cylinder (e.g., a cylinder wall 106, etc.).

[0016] Each of the pistons 103 may include one or more of the piston rings. In general, each of the pistons 103 typically has three piston rings, although in some embodiments, any number of the piston rings may be included.

[0017] As shown in Figure 2, the piston assembly 101 includes the piston 103, the oil control ring 100, a first piston ring 102, and a second piston ring 104. The oil control ring 100, described further herein, is typically positioned towards a lower portion of the piston 103 (e.g., downwards, lowest on the piston 103, etc.) and serves to scrape oil 105. The first piston ring 102 is typicallypositioned towards an upper portion of the piston 103 (e.g., upwards, highest on the piston 103, towards the combustion chamber, etc.) and is configured to create a seal for the combustion chamber to prevent loss of gases. The second piston ring 104 is positioned between the oil control ring 100 and the first piston ring 102. The second piston ring 104 is configured for a combined function of scraping and sealing. Each of the oil control ring 100, the first piston ring 102, and the second piston ring 104 operate independently.

[0018] An outer surface of the piston 103 may include one or more piston ring grooves (e.g., cavities, recesses, etc.) configured to receive one or more of the oil control ring 100, the first piston ring 102, or the second piston ring 104. For example, the oil control ring 100 may be positioned within the piston ring groove and may be maintained within the piston ring groove during translation of the piston assembly 101 within the cylinder.

[0019] The cylinder wall 106 of the cylinder is also shown in Figure 2. Each of the oil control ring 100, the first piston ring 102, and the second piston ring 104 are positioned between the piston 103 and the cylinder wall 106. The oil control ring 100 scrapes the oil 105 from the cylinder wall 106 so that the oil 105 may be returned to the engine system for further use by the engine system. As the excess oil 105 is returned to the engine system, it is beneficial to improve scraping to reduce oil consumption.

[0020] The oil scraping process reduces the amount of the oil 105 retained on the cylinder wall 106, which may provide benefits to the engine system. For example, low oil presence on the cylinder wall 106 reduces oil mist in the combustion chamber, which can help prevent pre-ignition. As another example, in a hydrogen engine system, less of the oil 105 retained on the cylinder wall 106 will reduce the possibility of emulsification of the oil 105 and water from the hydrogen engine system combustion process, maintaining the quality of the oil 105 for a longer period of time.

[0021] The oil control ring 100 includes the control ring core 108. The oil control ring core 108 interfaces with the piston 103 and is structured as a coil (e.g., spiral, etc.) and shaped substantially into a circle around an outer circumference of the piston 103. The control ring core 108 is positioned circumferentially and adjacent to an outer surface of the piston 103, such that an outer portion of each coil winding of the oil control ring core 108 is in contact with the outer surface of the piston 103. In some embodiments, the oil control ring core 108 may be structuredor positioned differently. For example, in some embodiments, the oil control ring core 108 may be structured as a solid ring.

[0022] The oil control ring core 108 interfaces with a rail ring 110. The rail ring 110 includes an inner curved surface 112 positioned adjacent to an outer surface of the oil control ring core 108. The inner curved surface 112 is shaped substantially similar to the curvature of the oil control ring core 108. The oil control ring core 108 is coupled to the inner curved surface 112 such that the rail ring 110 partially surrounds the oil control ring core 108. In the embodiment of Figure 2, the rail ring 110 borders approximately half of the outer surface of the oil control ring core 108. In some embodiments, the oil control ring core may be positioned differently within or in relation to the rail ring 110.

[0023] The rail ring 110 includes the first rail 114 and the second rail 116. The first rail 114 is positioned in an upper portion of the oil control ring 100 and the second rail 116 is positioned in a lower portion of the oil control ring 100, at a distance from the first rail 114. The first rail 114 and the second rail 116 protrude from the oil control ring 100 in a direction towards and adjacent to the cylinder wall 106 such that the first rail 114 and the second rail 116 are in contact with the cylinder wall 106, while at least a portion of the rail ring 110 of the oil control ring 100 is not in contact with the cylinder wall 106. In some embodiments, the first rail 114 and the second rail 116 may be structured or positioned differently with respect to the rail ring 110 of the oil control ring 100.

[0024] At least a portion of each of the first rail 114 and the second rail 116 is in contact with the cylinder wall 106. The first rail 114 may have a first width and the second rail 116 may have a second width not equal to the first width. The first width of the first rail 114 and the second width of the second rail 116 measure the width of the surface of each of the first rail 114 and the second rail 116 that is in contact with the cylinder wall 106. In the embodiment of Figure 2, the first width of the first rail 114 is greater than the second width of the second rail 116, i.e., the first rail 114 has a larger surface area in contact with the cylinder wall 106 than second rail 116. In some embodiments, the width of the second rail 116 may be greater than the width of the first rail 114 (meaning that the second rail 116 may have a larger surface area in contact with the cylinder wall 106 than the first rail 114), or the first rail 114 and the second rail 116 may have the same orsubstantially the same width (meaning that the first rail 1 14 and the second rail 1 16 have the same amount or substantially the same amount of surface area in contact with the cylinder wall 106).

[0025] As shown in Figure 2, the first rail 114 and the second rail 116 each include tapered side portions which taper from a greater width nearer to the rail ring 110 to a smaller width nearer to the cylinder wall 106. The tapered side portions nearer to the cylinder wall 106 culminate in a portion of each of the first rail 114 and the second rail 116 which form the first width of the first rail 114 and the second width of the second rail 116. The first width and the second width may comprise a flat, pointed, curved or other shaped portion of the first rail 114 and the second rail 116. The first rail 114 and the second rail 116 may take various shapes other than those shown in Figure 2.

[0026] Tangential tension between the first rail 114 and the second rail 116 and the cylinder wall 106 facilitates the scraping of the oil 105 down the cylinder wall 106 by the first rail 114 and the second rail 116. As tangential tension is increased, oil scraping may improve, however, frictional loss may increase. As the second rail 116 is positioned lower on the piston 103, the second rail 116 may come into contact with the oil 105 on the cylinder wall 106 before the first rail 114 comes into contact with the oil 105 on the cylinder wall 106. In this way, the second rail 116 has access to and contacts a greater amount of the oil 105. The function of unequal widths of the first rail 114 and the second rail 116, for example, the first rail 114 having a greater width than the second rail 1 16, is to allow higher unit pressure at the second rail 116. As such, the second rail 116 having a smaller width than the first rail 114 (and therefore less surface area in contact with the cylinder wall 106) allows for better oil scraping and reduced friction with the same overall tangential tension as would be present for rails of equal widths. The first rail 114 having a greater width than the second rail 116 (and therefore more surface area in contact with the cylinder wall 106) allows the system to retain overall friction and durability.

[0027] While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed but rather as descriptions of features specific to particular implementations. Certain features described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitablesubcombination. Moreover, although features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can, in some cases, be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0028] As utilized herein, the terms “approximately,” “generally,” and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.

[0029] The term “coupled” and the like, as used herein, mean the joining of two components directly or indirectly to one another. Such joining may be stationary (e.g., pemianent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two components or the two components and any additional intermediate components being integrally formed as a single unitary body with one another, with the two components, or with the two components and any additional intermediate components being attached to one another.

[0030] It is important to note that the construction and arrangement of the various systems shown in the various example implementations is illustrative only and not restrictive in character. All changes and modifications that come within the spirit and / or scope of the described implementations are desired to be protected. It should be understood that some features may not be necessary, and implementations lacking the various features may be contemplated as within the scope of the disclosure, the scope being defined by the claims that follow. When the language “a portion” is used, the item can include a portion and / or the entire item unless specifically stated to the contrary.

[0031] Also, the term “or” is used, in the context of a list of elements, in its inclusive sense (and not in its exclusive sense) so that when used to connect a list of elements, the term “or” meansone, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, Z, X and Y, X and Z, Y and Z, or X, Y, and Z (i.e., any combination of X, Y, and Z). Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y, and at least one of Z to each be present, unless otherwise indicated.

Claims

WE CLAIM:

1. An oil control ring for an engine piston, comprising: a control ring core having a substantially circular shape, an outer surface of the control ring core comprising a control ring core outer circumference; a first rail having a first width, the first rail disposed about the control ring core outer circumference; and a second rail having a second width, the second rail disposed about the control ring core outer circumference, and wherein the second rail is positioned at a distance from the first rail.

2. The oil control ring of claim 1, wherein the first width is not equal to the second width.

3. The oil control ring of claim 1, wherein the first rail is positioned in an upper portion of the oil control ring and the second rail is positioned in a lower portion of the oil control ring.

4. The oil control ring of claim 3, wherein the first width of the first rail is greater than the second width of the second rail.

5. The oil control ring of claim 1, wherein the first rail and the second rail are coupled to the control ring core.

6. The oil control ring of claim 1, wherein the first rail and the second rail are positioned between the control ring core and a cylinder wall.

7. The oil control ring of claim 1, wherein the control ring core comprises a coil.

8. The oil control ring of claim 1, wherein each of the first rail and the second rail define tapered side portions which taper from a greater width nearer to the control ring core to a smaller width nearer to a cylinder wall.

9. A piston assembly for an engine cylinder, comprising: a piston having a piston outer circumference; and an oil control ring coupled to the piston, the oil control ring comprising a first rail having a first width and a second rail having a second width, the first rail and the second rail disposed about the piston outer circumference and positioned between the piston and the engine cylinder.

10. The piston assembly of claim 9, wherein the first rail comprises an upper rail portion of the oil control ring and the second rail comprises a lower rail portion of the oil control ring.11 . The piston assembly of claim 10, wherein the first width of the upper rail portion is greater than the second width of the lower rail portion.

12. The piston assembly of claim 9, wherein the first rail and the second rail are positioned between the piston and the engine cylinder.

13. The piston assembly of claim 9 wherein the oil control ring further comprises a control ring core, the control ring core disposed about the piston outer circumference, such that the control ring core is positioned between the piston and the first rail and the second rail.

14. The piston assembly of claim 13, wherein the oil control ring defines an inner curved surface positioned adjacent to an outer surface of the control ring core.

15. The piston assembly of claim 9, further comprising:a first piston ring; and a second piston ring, the second piston ring positioned between the first piston ring and the oil control ring.

16. The piston assembly of claim 15, wherein the first piston ring is configured to form a first seal between the piston and a wall of the engine cylinder, and the second piston ring is configured to scrape oil along the wall of the engine cylinder and form a second seal between the piston and the wall of the engine cylinder.

17. The piston assembly of claim 15, wherein each of the first piston ring, the second piston ring, and the oil control ring are configured to operate independently.

18. The piston assembly of claim 15, wherein one of the first rail and the second rail is in contact with the engine cylinder and the other of the first rail and the second rail is positioned a distance away from the engine cylinder.

19. An oil control ring for an engine piston, comprising: a rail ring defining an inner curved surface, the rail ring comprising: a first rail having a first width, and a second rail having a second width being different than the first width, the second rail is positioned at a distance from the first rail; and a control ring core interfacing with the inner curved surface.

20. The oil control ring of claim 19, wherein the rail ring borders approximately half of an outer surface of the control ring core.

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