Internal combustion engine

Abstract

An internal combustion engine (10) includes a cylinder head (11), a piston (20), and an engine block (12). The piston (20) is slidably mounted in a cylinder bore (16) in the engine block (12) or in a cylinder liner (14) in the engine block for reciprocating motion between a top dead center (TDC) at a top of the cylinder bore (16) and a bottom dead center at a bottom of the cylinder bore (16). The cylinder bore (16) includes a cylinder wall (15), and at least one pocket (40) is recessed into the cylinder wall (15) for controlling oil flow during the reciprocating motion of the piston (20).

Description

Technical Field

[0001] This disclosure relates to an internal combustion engine, and more specifically, to an internal combustion engine having at least one recess in the cylinder wall for controlling oil. Background Technology

[0002] Internal combustion engine design continues to evolve to improve fuel economy and reduce emissions, through methods such as increasing power density, hybridization, and altering combustion strategies. The evolving operation and technology of engines are changing the boundary conditions between engine components and oil. This can lead to changes in the conventional operating conditions to which lubricating oil is exposed, such as reduced soot contamination, longer oil change intervals, and sustained exposure to higher temperatures and pressures within the combustion zone. Therefore, matching engine technology with oil formulation performance is crucial to ensuring that current failure modes do not introduce additional risks or increased risks.

[0003] In particular, many technologies implemented in internal combustion engines to control emissions result in higher temperatures or prolonged periods of high temperatures at or near the top piston ring commutation (TRTA) location on the cylinder bore or cylinder liner. These technologies may include, for example, using alternative fuels in conjunction with conventional fuels, as well as reducing size or speed. Higher TRTA temperatures mean that the oil (especially on the cylinder walls) may experience uncontrolled combustion, in addition to increased fuel consumption. The risk of evaporation of critical lubricant additives also increases due to the higher TRTA temperatures. These technologies alone can lead to unwanted emissions and / or increased engine wear.

[0004] US20120132069A1 discloses a cylinder bore for minimizing frictional losses, the cylinder bore including a plurality of oil dimples formed on the inner circumference of the cylinder bore during the stroke section, which contact the piston. The oil dimples are formed by laser honing and have different shapes during the stroke section or different shapes during the stroke section depending on the stroke speed. Furthermore, the structure of the oil dimples allows for the supply of more oil during the upward or downward stroke section compared to the center stroke section of the cylinder bore. Additionally, the oil dimples are formed symmetrically with respect to the center stroke section of the cylinder bore. Summary of the Invention

[0005] The purpose of this disclosure is to improve the operation of internal combustion engines with high top ring commutation temperatures. Another purpose is to prevent uncontrolled combustion caused by oil in or near the combustion chamber. Another purpose is to control fuel consumption and its impact on emissions. Another purpose is to control the consumption of certain additives in the fuel, particularly consumption resulting from the volatilization and / or combustion of such additives. Another purpose is to ensure that the fuel is controllable and reduces wear between the piston rings and the cylinder bore or cylinder liner. Another purpose is to improve the use of the fuel as a sealant to control blow-by velocity.

[0006] Therefore, this disclosure provides an internal combustion engine and method according to claims.

[0007] This disclosure relates to a manner in which oil is distributed across and along the cylinder bore / liner, which in some embodiments can be considered as oil flow along the cylinder bore / liner in the axial or circumferential direction or a combination thereof. This can include oil splash, oil film distribution due to piston ring movement, and oil present on the cylinder liner / bore honing. Throughout the document, the dynamic behavior of the mass distribution of oil along the cylinder bore / liner is considered as oil flow. Therefore, this disclosure relates to controlling oil flow, or controlling the distribution of oil across and along the cylinder bore / liner in or near the TRTA location, particularly to address the aforementioned technical problems associated with novel engine technologies. By controlling oil flow along the cylinder bore / liner by optimizing the surface texture of the cylinder bore / liner using the pattern of the oil reservoir, oil flow near or into the combustion chamber can be controlled and / or prevented. This suppresses abnormal combustion caused by oil (improving operation, particularly for internal combustion engines using alternative fuels, etc.), reduces fuel consumption, and reduces additive consumption (thereby reducing wear). An additional benefit is that the time for a complete oil film to form can be improved, thereby allowing the use of low-viscosity oils to reduce frictional losses. In addition, it can reduce the risk of oil failure modes associated with high power density architectures.

[0008] In some embodiments, an oil film between the cylinder liner / bore and the piston rings seals the combustion chamber. In certain cases, if the seal is compromised, blow-by gas can flow through the rings, leading to both increased emissions and disrupted piston ring dynamics. This seal can be strengthened by using surface-textured pits, as outlined below. Using surface-textured pits optimizes the seal to control emissions without increasing frictional losses. Using pits near the ring inversion point increases the rate of oil film formation, ensuring further reinforcement of the seal between the piston rings and cylinder liner, thereby further controlling piston ring dynamics. This can be further improved by optimizing the piston ring end clearance and surface texture together, thereby minimizing blow-by.

[0009] This disclosure provides an internal combustion engine. The internal combustion engine includes a cylinder head, a piston, and an engine block. The engine block has a cylinder bore, and the piston is slidably mounted in the cylinder bore for reciprocating motion between top dead center (TDC) at the top of the cylinder bore and bottom dead center at the bottom of the cylinder bore. The cylinder bore includes a cylinder wall. At least one recess is recessed into the cylinder wall to control oil flow during the piston's reciprocating motion.

[0010] This disclosure also provides a cylinder liner for an internal combustion engine. The cylinder liner includes a cylinder bore, and the internal combustion engine includes a cylinder head, a piston, and an engine block for positioning the cylinder liner therein. The piston is slidably mounted in the cylinder bore for reciprocating between top dead center (TDC) at the top of the cylinder bore and bottom dead center at the bottom of the cylinder bore. The cylinder bore includes a cylinder wall, with at least one recess recessed into the cylinder wall to control oil flow during the piston's reciprocating motion.

[0011] This disclosure also provides an engine block for an internal combustion engine. The engine block includes a cylinder bore, and the internal combustion engine includes a cylinder head and a piston. The piston is slidably mounted in the cylinder bore for reciprocating motion between top dead center (TDC) at the top of the cylinder bore and bottom dead center at the bottom of the cylinder bore. The cylinder bore includes a cylinder wall, with at least one recess recessed into the cylinder wall to control oil flow during the piston's reciprocating motion. Attached Figure Description

[0012] Embodiments of this disclosure will now be described by way of example only, with reference to and as illustrated in the accompanying drawings, wherein:

[0013] Figure 1 This is a cross-sectional view of a portion of the internal combustion engine disclosed herein, particularly showing the top portion of the cylinder of the internal combustion engine with the piston at top dead center.

[0014] Figures 2 to 4 yes Figure 1 Schematic two-dimensional diagrams of different embodiments of the recess layout on the cylinder wall of an engine;

[0015] Figures 5 to 7 It extends to Figure 1 The depth of the cylinder wall of the engine, including pits and / or Figures 2 to 4 Schematic cross-sectional views of different embodiments of the recess;

[0016] Figure 8 yes Figure 1 A schematic cross-sectional view of an engine illustrates the area and location of the recesses on the piston and cylinder wall around the top piston ring when the piston is at top dead center, wherein the recesses may include... Figures 2 to 7 The characteristics of any one of them;

[0017] Figure 9 This is an example Figure 1 A schematic plan view of the (enlarged) deformation of the cylinder wall and cylinder bore during engine operation; and

[0018] Figure 10 yes Figure 1A schematic cross-sectional view of an engine illustrates the area and location of the recesses on the piston and cylinder wall around the top piston ring when the piston is at bottom dead center, wherein the recesses may include Figures 2 to 7 The characteristics of any one of them. Detailed Implementation

[0019] The following description provides only preferred exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the subsequent description of preferred exemplary embodiments will provide those skilled in the art with an enabling description for implementing these preferred exemplary embodiments of the invention. It should be understood that various changes can be made to the function and arrangement of elements, including combinations of features from different embodiments, without departing from the scope of the invention. Specific details are set forth in the following description to provide a thorough understanding of the embodiments. However, those skilled in the art will understand that the embodiments can be practiced without these specific details. For example, well-known processes, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.

[0020] It should be understood that the following disclosure provides many different embodiments or examples for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify this disclosure. Of course, these are merely examples and not intended to be limiting. Furthermore, reference numerals and / or letters may be repeated in various instances of this disclosure. Such repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed. Furthermore, in the following description, the formation of a first feature on or above a second feature may include embodiments in which the first and second features are formed to be in direct contact, and may also include embodiments in which additional features may be formed to be inserted between the first and second features such that the first and second features may not be in direct contact. This flexibility is required in practice to allow the technology to be implemented in different iterations to allow the technology to be targeted for an intended use that varies depending on engine architecture, application usage patterns, or alternative fuels.

[0021] Figure 1 A partial cross-section of an internal combustion engine 10 (such as a diesel engine) is illustrated. The internal combustion engine 10 can power various types of applications and / or machines. For example, the internal combustion engine 10 can power generators or vehicles (such as off-highway machinery, railway locomotives), earthmoving machinery (such as wheel loaders, excavators, dump trucks, backhoe excavators, motorized graders, and material handling machines).

[0022] The internal combustion engine 10 includes a cylinder head 11 attached to an engine block 12. The engine block 12 has cylinder bores 16 to form cylinders or cylinder assemblies. As illustrated, the cylinder bores 16 may be formed by cylinder liners 14. The engine block 12 may include a chamber forming a liner bore 13, which is lined by the cylinder liner 14. The cylinder liner 14 includes an inner surface or cylinder wall 15 that defines the cylinder bore 16.

[0023] Alternatively, if the engine 10 does not include the cylinder liner 14, the cylinder bore 16 can be directly formed in the engine block 12. For example, in Figure 1 In this configuration, there is no cylinder liner 14, and the cylinder bore 16 is the same as the cylinder liner bore 13, wherein the cylinder wall 15 is formed by the engine block 12 itself.

[0024] The cylinder bore 16 is configured to receive a piston 20 slidably mounted therein, which reciprocates within the cylinder bore 16 during operation of the engine 10. When in use, the piston 20 is at the top dead center (TDC) position at the top of the cylinder bore 16 (e.g., ...). Figure 1 It reciprocates between the bottom dead center (BDC) position at the bottom of the cylinder bore 16 (as illustrated).

[0025] A combustion chamber 21 is formed within a volume defined between the cylinder bore 16, the cylinder head 11, and the piston 20. In the combustion chamber 21, a mixture of air and fuel is burned, thereby providing the power to drive the piston 20 away from the cylinder head 11.

[0026] The cylinder head 11 includes at least one valve 22 that allows one or more functions selected from: drawing air into the combustion chamber 21, drawing fuel into the combustion chamber 21, and expelling exhaust gases from the combustion chamber 21. Suitable types of internal combustion engines include spark-ignition engines or compression-ignition engines (e.g., diesel engines or natural gas-fueled engines). Additionally, dual-fuel engines, such as those using both liquid and gaseous fuels, may also be available.

[0027] The internal combustion engine 10 may include any number of cylinders. Each cylinder of the internal combustion engine 10 may have a single cylinder head 11. Alternatively, two or more cylinders may be associated with cylinder heads 11.

[0028] The engine 10 also includes at least one piston ring 30, 31 mounted to the piston 20, including a top ring 30. The at least one piston ring 30, 31 may include at least one additional ring 31. A single additional ring 31 is illustrated, although the additional ring 31 may be distributed along the piston.

[0029] At least one piston ring 30, 31 extends around the circumference of the piston 20 and may be positioned closer to the top or crown of the piston 20 than the opposite end of the piston 20. At least one piston ring 30, 31 contacts the cylinder wall 15 to slide along the cylinder wall with the aid of oil lubrication. The piston 20 may not normally contact the cylinder wall 15 during use because at least one piston ring 30, 31 separates the piston and the cylinder wall from each other.

[0030] The top ring 30 may be a compression ring for sealing the combustion chamber, such that during the power stroke, gases are substantially unable to escape from the combustion chamber around the top ring 30 or the piston 20. At least one additional ring 31 may be a compression ring for sealing cylinder gases, an oil scraper ring for managing the oil film on the cylinder wall 15, and / or an oil control ring for lubricating the cylinder wall and allowing heat dissipation.

[0031] At least one piston ring 30, 31 may comprise any suitable material and ring geometry, such as wedge-shaped, trapezoidal, barrel-shaped, rectangular (as illustrated), internally beveled, and / or conical. Oil may be supplied to the piston and cylinder bore 16 by any known means, such as through threaded holes in the connecting rod or piston crown and / or piston cooling nozzles.

[0032] The top ring land 32 separates the top of the piston 20 from the top ring 30, and the second ring land 33 extends below the top ring 30. The second ring land 33 may extend specifically to the other ring 31. The third and subsequent ring lands 34 separate the other ring 31 from the bottom of the piston.

[0033] A top ring 30 is located in a top recess 35 surrounding the outer periphery of the piston 20, and a top ring bank 32 may extend between the top of the piston 20 and the top edge of the top recess 35. At least one additional ring 31 is located in at least one additional recess 36, which may be separated from the adjacent recesses 35, 36 by a second ring bank 33, a third or additional ring bank 34.

[0034] As the piston 20 reciprocates within the cylinder bore 16, at least one piston ring 30, 31 contacts the cylinder wall 15. At least one piston ring 30, 31 typically deforms during this contact and acquires a different shape depending on the direction and speed of the piston 20's travel. For example, each piston ring 30, 31 is pushed towards the bottom of each groove 35, 36 during upward travel and towards the top of each groove 35, 36 during downward travel. Therefore, the shape of the ring contact area 38 changes at different stages of the engine cycle.

[0035] The ring contact area 38 is the contact area between the piston rings 30, 31 and the cylinder wall 15. The ring contact area 38 under such deformation can be determined or estimated through modeling and calculation, such as by using RINGPAK software provided by Realis Simulation Ltd. in the UK.

[0036] This disclosure relates in its entirety to controlling the flow of oil to, above, and / or around the top ring 30, particularly in response to higher TRTA temperatures. Whether formed by the cylinder liner 14 or directly by the engine block 12, the cylinder wall 15 includes at least one recess 40 for controlling the flow of oil during the reciprocating motion of the piston 20. The at least one recess 40 is a recess or cup in the cylinder wall 15 and may be formed in the cylinder liner 14 or the engine block 12. For example, the at least one recess 40 may be formed by laser etching or other manufacturing techniques.

[0037] At least one recess 40 may be configured to control oil flow, thereby distributing oil to areas requiring lubrication and preventing or minimizing uncontrolled combustion of the oil. At least one recess 40 may serve as an oil reservoir and may be configured to allow oil to enter and / or remain in the at least one recess 40 as the piston 20 passes through it.

[0038] Specifically, at least one recess 40 may be configured to control, reduce, and / or prevent upward flow of oil along the cylinder wall 15 above the position of the top ring 30 when the piston 20 is in the TDC (i.e., top ring reversal position, TRTA). This minimizes the amount of oil available for uncontrolled combustion in the combustion chamber 21.

[0039] Alternatively, at least one recess 40 may be configured to control, reduce, and / or prevent airflow downwards from the combustion chamber along the cylinder liner / bore, thereby controlling blow-by velocity. The recess 40 may be configured to control the gas flow rate downwards from the combustion chamber along the cylinder / bore in an attempt to control the piston ring land pressure and thus piston ring dynamics.

[0040] Finally, a recess 40 can be configured such that a cylinder bore / liner protrusion or cylinder bore / liner deformation can improve the geometrical consistency between the piston ring and the cylinder liner / bore.

[0041] At least one recess 40 may be manufactured according to the design of at least one piston ring 30, 31, and may specifically provide lubrication for the top piston ring 30 to reduce frictional losses in the engine 10. For example, the piston ring may be designed to have a specific contact area between the piston ring and the cylinder bore / liner. The recess 40 may then be designed to ensure that its geometry and / or surface area is smaller or larger than the contact area between the piston ring and the cylinder bore / liner interface. The exact relationship between the piston ring design and the cylinder bore / liner interface may vary depending on the location of the recess during the stroke, controlled to the level required for lubrication but not so high that the oil affects the flow of combustion.

[0042] Figures 2 to 4 An exemplary embodiment of a two-dimensional view illustrating a pattern of at least one recess 40 extending along the height H (i.e., the dimension along the reciprocating direction of the piston 200) and the width W (i.e., the dimension of the surface surrounding the cylinder wall 15 perpendicular to the height) of the cylinder wall 15 is shown. At least one recess 40 extends into the depth D of the cylinder wall 15. Each recess 40 extends along a recess width PW, a recess height PH, and a recess depth PD.

[0043] At least one pit 40 may include a plurality of pits 40 arranged in an array 45, the array including at least one row of adjacent pits 40 extending circumferentially around the cylinder wall 15. Figure 2 and Figure 3 The array 45 consists of a row, while Figure 4 The array consists of two rows.

[0044] Around array 45, the recesses 40 may have the same spacing, or the spacing may vary, as described below. Figure 9 Further discussion is needed. The spacing can be regular (i.e., the spacing is the same or the spacing varies in a regular way) or irregular (i.e., the spacing variation does not have a substantial pattern). The spacing between the pits 40 needs to be suitable for avoiding damage to the oil film while controlling the amount of oil guided above the top ring 30 at the TDC.

[0045] The distance between adjacent recesses 40 along the width W of the cylinder wall 15 can be similar to or larger than the size of the recess (such as the recess height PH) itself. If the array 45 consists of multiple rows, the distance between adjacent rows along the height H of the cylinder wall 15 can be similar to or larger than the size of the recess (such as the recess height PH) itself.

[0046] Array 45 may extend across array height AH. If array 45 consists of a single row, then array height AH is the height of a single recess 40. If array 45 consists of multiple rows extending along the height H of cylinder wall 15, then array height AH is the height between the top of the recess 40 in the top row and the bottom of the recess 40 in the bottom row.

[0047] The pit depth (PD) can range from about 1 micrometer to about 100 micrometers. The pit height (PH) and / or pit width (PW) can range from about 1 micrometer to about 1 mm or about 2 mm.

[0048] The recesses 40 in array 45 may each have the same shape. Alternatively, the recesses 40 surrounding array 45 may have different shapes, particularly in cases where certain areas around the circumference of cylinder wall 15 have different oil control requirements (e.g., due to cylinder bore deformation, as described below). Figure 9 (To be discussed further).

[0049] like Figure 2 As illustrated, the height PH of the pit 40, or each pit 40, may be greater than the width PW, and may include substantially vertical lines or dashed lines. For example... Figure 4 As illustrated, the pit 40 or the pit width PW of each pit 40 may be greater than the pit height PH, and may include substantially horizontal lines or dashed lines.

[0050] like Figure 3 As illustrated, a recess 40 or each recess 40 may include at least a portion extending at an acute angle to the height H and / or width W of the cylinder wall 15. A recess 40 or each recess 40 may have a herringbone shape as illustrated, radiating downwards from the top of the cylinder wall 15. The radiating herringbone shape from the top can be advantageous in extruding oil through each leg of the herringbone shape in an attempt to minimize or control the oil flow to the top of the cylinder bore / liner.

[0051] Figures 5 to 7 An exemplary embodiment of the shape of at least one recess 40, or the recess depth PD of each recess 40, is illustrated by a cross-section taken across the depth D and height H of the cylinder wall 15. For clarity, the illustrated variations in depth are magnified. The recess depth PD may be substantially the same or vary along the recess height PH.

[0052] like Figure 5 As shown, the pit depth PD along the pit height PH can be V-shaped, such as a symmetrical V-shape, and the pit depth PD can decrease on either side away from the deepest position of at least one pit 40. The V-angle can be used to control the oil flow toward the top of the cylinder bore / cylinder liner.

[0053] like Figure 6 As shown, the pit depth PD can be U-shaped, and at least one pit 40 can have a continuous pit depth PD along the pit height PH.

[0054] like Figure 7As shown, at least one recess 40 may have an asymmetrical V-shaped recess depth PD. Specifically, the deepest point of at least one recess 40 may be offset from the center along the recess height PH, and the deepest point of at least one recess 40 may be closer to the top rather than the bottom of at least one recess 40. This arrangement means that when at least one piston ring 30, 31 passes through at least one recess 40 and presses oil into it, the oil is guided downwards rather than upwards out of at least one recess 40.

[0055] Figure 8 A piston 20 in a TDC (Transmission Controlled Domain) is schematically illustrated, wherein a top ring 30 contacts the cylinder wall 15 on a top ring contact area 38, and different embodiments of positions 50, 51, 52 of at least one recess 40 relative to the top ring 30 along the height H of the cylinder wall 15 are illustrated. At the different positions 50, 51, 52, the at least one recess 40 may include any of the shapes, sizes, arrays, and / or arrangements discussed above.

[0056] At least one recess 40 may be located on the cylinder wall 15 such that when the piston 20 is in TDC (Transmission Controlled Flow), the recess height PH at least partially overlaps with the top ring contact area 38 or the top ring 30. The overlap of at least one recess 40 with the top ring contact area 38 along the recess height PH may be at least 25%, at least 50%, or at least 75% of the height H of the top ring contact area 38. The recess may also, or alternatively, be located exactly below this position, allowing 0% overlap, but for throttling or controlling flow to that position.

[0057] In the case of an array of pits 40, the total combined area of ​​the cylinder wall 15 covered by the pits 40 on the cylinder wall 15 (i.e., the total area of ​​the indentations excluding the space between the pits 40) can be at least 0.5%, at least 1%, at least 5%, or at least 10% of the top ring contact area 38.

[0058] At least one pit 40 can span Figure 8 Positions 50, 51 and / or 52 and / or as shown Figure 10 Positions 70 and 71 shown are used for positioning or extension.

[0059] In the embodiment illustrated by position 51, at least one recess 40 is positioned such that, when the piston 20 is at TDC, the recess height PH of at least one recess 40 partially overlaps with the top ring contact area 38, and at least one recess 40 is located below or separate from the upper edge 55 of the top ring contact area 38. At least one recess 40 may also extend at TDC along the recess height PH beyond the top ring contact area 38 and below the top ring 30 and the top ring contact area 38, as illustrated. The recess height PH may be equal to or greater than the height of the top ring contact area 38 (this area may be the area when the top ring 30 passes through at least one recess 40).

[0060] Therefore, as the piston 20 moves downward from the TDC, the contact area between the top ring 30 and the cylinder wall 15 above at least one recess 40 forces oil downward from above the top ring 30. Some oil will extend above at least one recess 40 to provide lubrication, but separating the oil reservoir in at least one recess 40 from the top of the top ring 15 means that at the TDC, oil will never reach above or substantially above the top ring 30.

[0061] At position 51, at least one recess 40 may be configured to prevent oil shortage. Specifically, if the top ring 30 is stationary on at least one recess 40, oil may be squeezed out of the at least one recess 30 while the top ring is stationary. Therefore, when the top ring 30 moves downwards, at least one recess 40 may be empty of oil, resulting in oil shortage. Therefore, the dimensions of at least one recess 40 (such as recess width PW and / or recess depth PD) may be configured to prevent such oil shortage. For example, the recess depth PD may be larger, such as greater than at least one recess 40 that does not overlap with the top ring contact area 38 at TDC, such that more oil is retained in the at least one recess and is not pushed out when the top ring 30 is stationary.

[0062] When in position 51, at least one pit 40 may have the following characteristics: Figure 3 The herringbone shape is shown. Because the legs of the herringbone shape extend below the top ring contact area 38 at the TDC, the oil is guided efficiently downward and away from the combustion chamber along both legs (instead of along one leg as in the vertical embodiment).

[0063] When in position 51, at least one pit 40 may have the following characteristics: Figure 7 The pit depth PD shown is asymmetrical and V-shaped. As discussed above, oil will tend to flow downwards in a more controlled manner, and this type of pit depth PD facilitates the oil flow required at location 51.

[0064] However, while such a location 52 of at least one recess 40 prevents oil from rising above the top ring 30 at the TDC, it may not provide sufficient lubrication for at least one piston ring 30, 31. When at least one recess 40 is positioned below the top ring 30 at the TDC, the at least one recess can be configured to control the upward flow of oil along the cylinder wall 15, such that oil does not substantially extend above the top ring 30 or the top ring contact area 38 at the TDC. Therefore, at least one recess 40 is configured to have a volume suitable for throttling the upward flow of oil along the cylinder wall 15. This volume can be configured such that when the top ring 30 passes through at least one recess 40, a sufficient but not excessive amount of oil is carried upward along the cylinder wall 15, and the oil does not substantially extend above the top ring 30 or the top ring contact area 38 at the TDC.

[0065] The distance between at least one recess 40 and the top ring 30 at TDC (i.e., the distance between the top edge of at least one recess and the lower edge 56 of the top ring contact area 38) can be configured to control oil flow based on the ring reversal time (i.e., the time it takes for the top ring 30 to travel through at least one recess 40, reach TDC, and return to the at least one recess 40). Specifically, the position and size of at least one recess 40 can allow the oil flow or oil film to remain on the cylinder wall 15 for a longer period than the ring reversal time. Therefore, when the top ring 30 is at TDC, at least one recess 40 can be located within a range of approximately 0.1 mm to approximately 100 mm below the top ring contact area 38 (e.g., below the lower edge 56 of the top ring contact area 38).

[0066] Therefore, at least one recess 40 may be located at the TDC in a second row or additional row, such as at position 52, below the top ring 30 and outside the top ring contact area 38.

[0067] At position 52, at least one pit 40 may have a different shape than at position 51 in order to facilitate oil distribution therearound, such as including vertical or horizontal lines. Figure 5 The V-shape shown.

[0068] Alternatively, as illustrated by position 50, at least one recess 40 may be positioned such that when the piston 20 is in the TDC (Transient Directional Control), the recess height PH of at least one recess 40 substantially overlaps with the entire top ring contact area 38. Thus, when the piston 20 is in the TDC, at least one recess 40 extends along the entire height of the top ring 30. In such an arrangement, the recess depth PD can be discrete or continuous, such as... Figure 6 As shown.

[0069] The position, density, size, shape and / or spacing of the recesses 40 around the cylinder bore 16 and the cylinder wall 15 may also be varied and / or configured to adapt to the deformation of the cylinder bore 16 in use.

[0070] Specifically, the density and / or size of the pits 40 in this row or each row can vary around the circumference of the cylinder wall 15. In areas of relatively strong oil flow around the circumference (such as areas where the piston 20 is farther from the cylinder wall 15), the density and / or size of the pits 40 can be increased (e.g., the spacing between the pits 40 is smaller). In areas of relatively weak oil flow around the circumference (such as areas where the piston 20 is closer to the cylinder wall 15), the density and / or size of the pits 40 can be decreased (e.g., the spacing between the pits 40 is larger). This can also vary depending on the location along the cylinder bore / liner. Along the cylinder bore / liner, the pit density and size may vary to accommodate both cylinder bore deformation and oil film thickness. For example, in the stroke region of a fully submerged film, the density of the pits can vary circumferentially to accommodate cylinder bore deformation. For instance, the circumferential density of the pits increases for thicker films and decreases for thinner films. However, in the stroke region of mixed friction, the density of the pits may increase for thicker films and decrease for thinner films. Conversely, the density of the pits may decrease for thicker films and increase for thinner films surrounding the circumference of the cylinder bore, which also varies longitudinally.

[0071] The shape and position of the pit 40 can also vary depending on the location of stronger or weaker oil flow. In areas of relatively strong circumferential oil flow, the pit 40 can be positioned such that it at least partially overlaps with the top ring 30 at the TDC (i.e., position 50 or 51). In areas of relatively weak circumferential oil flow, the pit 40 can be positioned such that it does not overlap with the top ring 30 at the TDC (i.e., position 52).

[0072] By example Figure 9 This is a plan view of the top of the cylinder bore 16 and the engine block 12, schematically illustrating known deformations of the cylinder bore 16 caused by the high temperatures and pressures during operation, such as those resulting from the position of the bolt 60 around the cylinder bore 16. Specifically, the deformation can result in a “narrowing point” 62, which can be driven by the bolt position 60, closer to the cylinder wall 15 and piston 20 than the widening point 61. In existing systems, oil flow is uneven because oil movement is inhibited by the narrowing point 62 and facilitated by the widening point 61. This bulge or deformation can also be forced by creating indentations in different ways under ignition conditions, also for the purpose of controlling oil flow.

[0073] Therefore, the recesses 40 may be spaced around the circumference of the cylinder wall 15 to promote or increase oil flow at the narrowing point 62 and inhibit or reduce oil flow at the widening point 61. Thus, compared to the density and / or size of the recesses 40 at the widening point 61, the narrowing point 62 may provide recesses 40 with increased density and / or size, or a shape with improved oil flow.

[0074] Because improved oil control is required, the pit 40 can be located at position 50 or 51 at the enlargement point 61. The pit can be located at position 52 at the narrowing point 62 (i.e., below the top ring 30 at the TDC), since less oil control is required as the narrowing point 62 is assumed to inhibit oil flow itself.

[0075] Additionally or alternatively, at least one recess 40 may be substantially below the top ring 30 at the TDC, such as at a position towards or adjacent to the top ring 30 at the BDC. Controlling the oil flow away from the TRTA may affect the oil quantity at the TRTA, thereby controlling the oil flow at the TDC above or to the top ring contact area 38. For example, at least one recess 40 may be located at or adjacent to the position of the top ring 30 at the BDC, or may be located between the positions of the top ring 30 at the TDC and the BDC.

[0076] Specifically, at least one recess 40 may be located at any position along the cylinder wall 15, at which metal-to-metal contact between the piston 20 and the cylinder wall 15 may occur during the reciprocating motion of the piston 20. Therefore, at least one recess 40 may be located within a region of 0% to 25%, 0% to 50%, or 0% to 75% of the height H from the position of the top ring 30 at the BDC to the position of the top ring 30 at the TDC.

[0077] Figure 10 An example is shown of the top ring 30 when the piston 20 is in the BDC position. Specifically, at least one recess 40 may be positioned adjacent to the top ring contact area 38, such as at position 71, and may not overlap with the top ring contact area 38 or the top ring 30 at the BDC. Therefore, since the top ring 30 does not stop on at least one recess 40 during piston 20 reversal at the BDC, oil is not ejected from at least one recess 40, thus maintaining sufficient oil for lubrication at that position.

[0078] Similar to position 52 at TDC, the distance between at least one recess 40 at BDC and the top ring 30 (i.e., the distance between the bottom edge of at least one recess and the top edge 55 of the top ring contact area 38) can be configured to control oil flow based on the ring reversal time (i.e., the time it takes for the top ring 30 to travel through at least one recess 40, reach BDC, and return to the at least one recess 40). Specifically, the position and size of at least one recess 40 can allow the oil flow or oil film to remain on the cylinder wall 15 for a longer period than the ring reversal time. Therefore, when the top ring 30 is at BDC, at least one recess 40 can be located above the top ring contact area 38 (e.g., above the upper edge 55 of the top ring contact area 38) within a range of approximately 0.1 mm to approximately 100 mm.

[0079] Furthermore, at the BDC, the recess height PH of at least one recess 40 adjacent to the top ring 30 may be less than the height of the top ring 30 or the top ring contact area 38. Therefore, when the top ring 30 passes through at least one recess 40, oil will not be squeezed out from the at least one recess 40, thus maintaining sufficient oil at that location for lubrication.

[0080] Alternatively, as illustrated by position 71, when piston 20 is in the BDC position, at least one recess 40 may at least partially overlap with the top ring 30 and the top ring contact area 38. This prevents oil loss below the top ring 30 at the TDC position, and allows oil to be expelled from the at least one recess 40 in an upward direction as piston 20 moves upward. In a manner similar to position 51 at the TDC position, the size and geometry of the at least one recess may be arranged such that oil flow is forced upward, and at a rate such that the movement of the top ring 30 at the start of its upward stroke always leaves oil between the cylinder bore / liner and the top ring 30. Thus, the size of the recess forces oil to flow upward, but at a rate such that sufficient lubrication remains without causing wear as the top ring 30 moves, meaning the geometry of the recess is a function of the velocity of the top ring 30 near and around the bottom reversing position.

[0081] At position 71, at least one recess 40 may be configured to prevent oil shortage. Specifically, if the top ring 30 is stationary on at least one recess 40, oil may be squeezed out of the at least one recess 30 while the top ring is stationary. Therefore, when the top ring 30 moves upward, at least one recess 40 may be empty of oil, resulting in oil shortage. Therefore, the dimensions of at least one recess 40 (such as recess width PW and / or recess depth PD) may be configured to prevent such oil shortage. For example, the recess depth PD may be larger, such as greater than at least one recess 40 that does not overlap with the top ring contact area 38 at BDC, such that more oil is retained in the at least one recess and is not pushed out when the top ring 30 is stationary.

[0082] Such oil control, performed at positions 70, 71 and at at least one recess 40 along the cylinder wall 15 between the TDC and BDC top ring 30 positions, can provide adequate lubrication around the bottom or middle of the cylinder wall 15, but oil control at that position may also result in oil control around the top ring 30 at the TDC.

Claims

1. An internal combustion engine, the internal combustion engine comprising: Cylinder head; piston; An engine block having a cylinder bore, and a piston slidably mounted in the cylinder bore for reciprocating motion between top dead center (TDC) at the top of the cylinder bore and bottom dead center at the bottom of the cylinder bore, the cylinder bore including a cylinder wall. At least one of the recesses is recessed into the cylinder wall to control the oil flow during the reciprocating motion of the piston; and At least one piston ring, including a top ring, is mounted to the piston, wherein the at least one recess is configured to control the oil flow to, across, and / or above the top ring when the piston is at or near TDC, to prevent uncontrolled combustion of the oil in the combustion chamber.

2. The internal combustion engine according to claim 1, wherein: The internal combustion engine includes a cylinder liner, and the engine block includes a cylinder liner bore, the cylinder liner being mounted in the cylinder liner bore, the cylinder liner forming the cylinder bore such that the at least one recess is formed in the cylinder liner; or The cylinder bore is formed directly in the engine block, such that the at least one recess is formed in the engine block.

3. The internal combustion engine according to any of the preceding claims, wherein the at least one recess is used to control the oil flow upward toward the top of the cylinder bore and / or to control the downward airflow.

4. The internal combustion engine according to any of the preceding claims, wherein the volume between the cylinder bore, cylinder head and piston forms a combustion chamber, optionally wherein the at least one recess is used to control the flow of oil into the combustion chamber to prevent uncontrolled combustion of the oil in the combustion chamber.

5. The internal combustion engine according to any one of the preceding claims, wherein at least one recess is located on the cylinder wall and at least partially overlaps the top ring when the piston is in TDC.

6. The internal combustion engine of claim 5, wherein at least one recess completely overlaps with the top ring when the piston is in TDC, and / or at least one recess extends along the cylinder wall below the top ring when the piston is in TDC.

7. The internal combustion engine according to claim 5 or claim 6, wherein at least one recess partially overlaps with the top ring when the piston is in TDC, such that the at least one recess is located below and separate from the upper edge of the top ring contact area between the top ring and the cylinder wall.

8. The internal combustion engine according to any of the preceding claims, wherein at least one recess does not overlap with the top ring when the piston is in TDC, optionally, wherein the at least one recess is located at a distance of approximately 0.1 mm to approximately 100 mm from the top ring when the piston is in TDC.

9. The internal combustion engine according to any of the preceding claims, wherein the at least one recess comprises a plurality of recesses arranged in an array, the array comprising at least one row of adjacent recesses extending circumferentially around a cylinder wall.

10. The internal combustion engine of claim 9, wherein the spacing between each recess along the row or each row is the same, and / or wherein the spacing between each recess along the row or each row is varied.

11. The internal combustion engine according to claim 9 or claim 10, wherein the position, density, size, shape and / or spacing of the recesses around the circumference of the cylinder wall are varied, and / or the recesses are configured to adapt to the deformation of the cylinder bore during use.

12. The internal combustion engine according to any one of claims 9 to 11, wherein: In the region of the cylinder wall where the oil flow is relatively strong, the density and / or size of the pits are relatively large. In the region of the cylinder wall where the oil flow is relatively weak, the density and / or size of the pits are relatively small. In the region of the circumference where the oil flow is relatively strong, the recess is positioned to at least partially overlap with the top ring at the TDC. And / or In areas where the oil flow is relatively weak around the circumference, the recess is positioned so that it does not overlap with the top ring at the TDC.

13. The internal combustion engine according to any one of the preceding claims, wherein: The at least one recess has a herringbone, horizontal, or vertical shape along its width and height; and / or The at least one pit has a pit depth that is the same or varies along the pit height, such as being symmetrical or asymmetrical in the shape of a V or U.

14. A cylinder liner for an internal combustion engine, the cylinder liner including a cylinder bore, and the internal combustion engine comprising: Cylinder head; piston; An engine block for positioning the cylinder liner within the engine block, such that the piston is slidably mounted in the cylinder bore for reciprocating motion between top dead center (TDC) at the top of the cylinder bore and bottom dead center at the bottom of the cylinder bore. The cylinder bore includes a cylinder wall, with at least one recess recessed into the cylinder wall to control oil flow during the reciprocating motion of the piston. and At least one piston ring, including a top ring, is mounted to the piston, wherein the at least one recess is configured to control the oil flow to, across, and / or above the top ring when the piston is at or near TDC, to prevent uncontrolled combustion of the oil in the combustion chamber.

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