A piston for reciprocating movement within a cylinder in an internal combustion engine

Abstract

A piston has a piston body having an upper end opposite a lower end with a central axis extending between the upper end and the lower end. The piston body includes a piston bowl having a piston bowl surface with a half-section profile including a central bottom portion and a target sidewall extending between a first separation cliff and a second separation cliff. The central bottom portion extends radially from the central axis to the first separation cliff at a central slope. The target sidewall extends at a slope different from the central slope. The target sidewall receives fuel from an oil injector at a spray angle that avoids contact with the first separation cliff, thereby enabling a more optimal fuel to air mixture to delay a peak in a burn rate. The second separation cliff extends at a slope that directs a fuel plume away from and out of contact with the second separation cliff to enable a peak burn.

Description

Technical Field

[0001] This application generally relates to a piston that reciprocates within a cylinder in an internal combustion engine, and more specifically to a piston having a distinctive piston cup profile. Background Technology

[0002] A diesel engine has multiple cylinders, each containing a reciprocating piston. A piston cup is located at the top of the piston. The piston cup, together with the upper part of the cylinder and the cylinder head, forms a combustion chamber where fuel is injected and burned. The piston cup is designed to facilitate the mixing of air and fuel and to create flow patterns that influence combustion and emissions within the combustion chamber. In a diesel engine, fuel is injected as a fuel spray into the combustion chamber during the piston's power stroke. Shortly after injection, the fuel is ignited by the compression pressure and heat within the combustion chamber.

[0003] Further contributions are needed in this technological field to improve engine efficiency and meet lower NOx emission requirements. Summary of the Invention

[0004] According to one aspect, a piston for reciprocating within a cylinder in an internal combustion engine, the piston comprising: a piston body having an upper end opposite to a lower end, a central axis extending between the upper end and the lower end, wherein the upper end includes an annular top surface defining the upper plane, the upper end including a piston cup recessed relative to the upper plane defined by the annular top surface, wherein the piston cup includes a piston cup surface having a half-section profile including: a central bottom portion, the central bottom portion being... A portion extends radially from the central axis to a first separation steep edge with a central slope that is negative relative to the central axis; wherein the first separation steep edge is defined by the intersection of the central bottom portion and the target sidewall; wherein the target sidewall extends between the first separation steep edge and the second separation steep edge, wherein the target sidewall extends with a slope different from the central slope, and the target sidewall is configured to receive fuel from the injector; and wherein the second separation steep edge extends with a slope that is positive relative to the central axis to guide fuel away from the second separation steep edge.

[0005] In one embodiment, the piston bowl has a bowl radius defined between the central axis and the annular top surface, wherein the first separation flange is located between 10% and 75% of the bowl radius.

[0006] In one embodiment, the piston bowl has a bowl radius defined between the central axis and the annular top surface, wherein the second separation flange is located between 50% and 90% of the bowl radius.

[0007] In one embodiment, the target sidewall includes an annular first sidewall portion having a length extending radially outward from the first separating edge to an inflection point measured relative to the central axis.

[0008] In one embodiment, the first sidewall portion includes a vertical portion that extends from the first separating edge to the inflection point.

[0009] In one embodiment, the first sidewall portion is located below the central bottom portion as measured relative to the central axis.

[0010] The piston according to claim 4, wherein the first sidewall portion has a slope different from the central slope.

[0011] In one embodiment, the inflection point defines the lowest point of the piston bowl surface as measured relative to the central axis.

[0012] In one implementation, the inflection point represents the change in the slope direction of the target sidewall measured relative to the central axis from a negative slope to a positive slope.

[0013] In one embodiment, the target sidewall includes an annular second sidewall portion having a length extending from the inflection point to the second separation edge.

[0014] In one embodiment, the second sidewall portion extends from the central axis at an angle between 70 and 90 degrees.

[0015] In one embodiment, the second sidewall portion has a positive slope relative to the central axis.

[0016] The present invention is provided to introduce a series of concepts further described below in exemplary embodiments. The present invention is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help limit the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits will become apparent from the following description and drawings. Attached Figure Description

[0017] The concepts described herein are illustrated by way of example rather than by way of limitation in the accompanying drawings. For the sake of clarity and simplicity, elements illustrated in the drawings are not necessarily drawn to scale. Where appropriate, reference numerals are repeated in the drawings to indicate corresponding or similar elements.

[0018] Figure 1 It is a schematic vertical section taken along the central axis of the cylinder of a diesel engine according to the first embodiment of this disclosure.

[0019] Figure 2 It is a schematic vertical section taken along the central axis of the cylinder of a diesel engine according to the second embodiment of this disclosure.

[0020] Figure 3 It is a schematic vertical section taken along the central axis of the cylinder of a diesel engine according to the third embodiment of this disclosure.

[0021] Figure 4 It is a schematic vertical section taken along the central axis of the cylinder of a diesel engine according to several embodiments of this disclosure. Detailed Implementation

[0022] To facilitate an understanding of the principles of this disclosure, reference will now be made to the embodiments illustrated in the accompanying drawings, and these embodiments will be described using specific language. However, it should be understood that this is not intended to limit the scope of the invention, and any changes and further modifications to the illustrated embodiments, as well as any further applications of the inventive principles that would normally occur to those skilled in the art as illustrated herein, are within the scope of this invention.

[0023] Now for reference Figures 1 to 3 In the description of this application, the vertical section is taken along the common central axis CA of the cylinders 10 included in a diesel engine according to various embodiments. Unless otherwise stated, similar reference numerals are used. Figures 1 to 3 The embodiment illustrated herein. A piston 12 for reciprocating motion within a cylinder 10 in an internal combustion engine (not illustrated) is illustrated. In the cylinder 10, the piston 12 is configured to reciprocate within the cylinder 10 along a common central axis CA. The piston 12 includes a piston body 19 having an upper end 20 opposite to a lower end 22, with the central axis CA and an outer peripheral enveloping surface 24 extending between the upper and lower ends. The enveloping surface 24 has a cylindrical shape. An annular top surface 26 is provided at the upper end 20 of the piston 12. The upper end 20 of the piston 12 includes a piston cup 14 recessed relative to an upper plane defined by the annular top surface 26. The piston cup 14 is surrounded by the annular top surface 26. The annular top surface 26 has a length extending from the upper end 20 to an annular edge 28.

[0024] The piston cup 14, together with the inner wall of the cylinder 10 and the inner surface of the cylinder head 16, forms the combustion chamber 18. In some embodiments, the cylinder head 16 assembled with the piston 12 and piston cup 14 is flat or substantially flat. An injector 20 is mounted on the cylinder head 16 and positioned above the piston cup 14, aligned with the central axis CA. Thus, the injector 20 is concentric with the piston cup 14 and the cylinder 10. The injector 20 includes a plurality of nozzles 21 formed at the lower end of the injector nozzle assembly for allowing high-pressure fuel to flow at high pressure from the injector nozzle chamber of the injector 20 into the combustion chamber 18, thereby promoting mixing of the fuel with hot compressed air within the combustion chamber 18. It should be understood that the injector 20 can be any type of injector capable of injecting high-pressure fuel into the combustion chamber 18 through the plurality of nozzles 21. The nozzles 21 provide a fuel spray 48 to the piston cup 14 at a spray angle A1 relative to the central axis CA, as described below. The nozzle 21 of the injector 20 is arranged such that the fuel spray 48 is injected in a certain direction (illustrated by arrow 52) past the first separation edge or steep edge 35 toward the inflection point 45. The injection of the fuel spray 48 crosses or passes over the first separation edge or steep edge 35. The nozzle 21 of the injector 20 is arranged such that the fuel spray 48 is injected in a certain direction (illustrated by arrow 52) past the first separation edge or steep edge 35 toward the inflection point 45. The injection of the fuel spray 48 crosses or passes over the first separation edge or steep edge 35. The alignment of the fuel spray 48 is such that it does not impinge before the first separation edge or steep edge 35, but crosses the first separation edge or steep edge 35 to induce turbulent vortices. An intake port (not shown) may be provided in the cylinder head 16 for supplying air to the combustion chamber 18 via an intake valve (not shown). In addition, an exhaust port (not shown) may be provided in the cylinder head 16 for discharging exhaust gas via an exhaust valve (not shown). Fuel sources may include diesel, biodiesel, gasoline (such as in gasoline compression ignition), or natural gas in high-pressure direct injection engines.

[0025] In the illustrated embodiment, the piston cup 14 has a piston cup surface 15 that forms a piston cup profile, which is rotationally symmetrical about a central axis CA and extends from the central axis CA to an annular edge 28. The piston cup profile controls the compression ratio and peak combustion. The piston cup surface 15 and the corresponding piston cup profile of the piston cup 14 achieve higher combustion rates to achieve better combustion efficiency. The piston cup surface 15 and the corresponding piston cup profile are optimized for specific engine power or different operating conditions. The piston cup surface 15 of the piston cup 14 includes a central bottom portion 32, a first separating edge or steep flange 35, a second separating edge or steep flange 46, and a target sidewall 40 positioned between the first separating edge or steep flange 35 and the second separating edge or steep flange 46.

[0026] The central bottom portion 32 slopes downwards with a central slope 34 from its center point or top 36 located on the central axis CA to the first separating edge or steep flange 35. The central slope 34 can be constant or variable along the length of the central bottom portion 32. Typically, the central slope 34 is a negative slope. The central bottom portion 32 is conical or convexly curved. The top 36 of the central bottom portion 32 is located horizontally below the upper plane defined by the annular top surface 26.

[0027] The first separation edge or steep edge 35 is the lowest point of the central bottom portion 32. The first separation edge or steep edge 35 is separated from the second separation edge or steep edge 46 by a target sidewall 40 configured to receive fuel spray 48 from the nozzle 21 of the injector 20. The first separation edge or steep edge 35 enables fuel-air mixing due to the turbulence generated after the fuel spray 48 encounters the target sidewall 40. The first separation edge or steep edge 35 does not cause the fuel spray 48 to deviate from the target sidewall 40. The first separation edge or steep edge 35 is positioned to increase turbulence and achieve better fuel-air mixing when the fuel spray 48 encounters the target sidewall 40. It is advantageous to position the first separation edge or steep edge 35 within a range of 20% to 40% of the radius of the piston cup surface 15 relative to the central axis CA. In one embodiment, the first separation edge or steep edge 35 is located at approximately 33% of the radius of the piston cup surface 15 and the corresponding piston cup profile.

[0028] The fuel spray 48 from nozzle 21 has a small spray angle A1 and is oriented to impact the target sidewall 40 just past the first separating edge or steep edge 35. The spray angle A1 is measured relative to the centerline of the fuel spray 48. When the piston is at top dead center (TDC), the spray angle A1 does not contact the first separating edge or steep edge 35, but deviates from about 0.5° to about 5°, and in some embodiments, this deviation is about 1° for optimal fuel-air mixing. The spray angle A1 of nozzle 21 is flexible, but the fuel spray 48 is oriented to impact the target sidewall 40 and avoids and / or minimizes any contact with the first separating edge or steep edge 35. In one embodiment, the spray angle A1 is between 60 and 80 degrees relative to the central axis CA of piston 12. The positioning of the first separating edge or steep edge 35 can be changed to avoid or minimize any contact with the fuel spray 48, such that the spray angle A1 of nozzle 21 is aligned with the fuel spray 48 to flow over the first separating edge or steep edge 35.

[0029] Fuel spray 48 flows at a small angle or distance over or across the first separation edge or steep rim, then contacts the target sidewall 40 of the piston bowl 14 to form a plume 148. The target sidewall 40 surrounds the central bottom portion 32 and the first separation edge or steep rim 35. The target sidewall 40 has a length extending from the first separation edge or steep rim 35 to the second separation edge or steep rim 46. When fuel spray 48 contacts the target sidewall 40, the length and slope of the target sidewall 40 slow down the combustion of the fuel spray 48. The peak combustion rate is delayed due to the length of the target sidewall 40 and the contact between the fuel spray 48 and the target sidewall 40.

[0030] Upon encountering the target sidewall 40, the fuel spray 48 forms a plume 148 that creates a separated shear layer and a recirculation zone, which facilitates fuel-air mixing. The shear layer of the plume 148 comprises a top surface or top portion 50 and a bottom portion 51. A first separation edge or steep edge 35 enables fuel-air mixing due to turbulence generated on the top surface or top portion 50 and either side of the plume 148 within the target sidewall 40. Due to the change in slope from the first separation edge or steep edge 35 to the target sidewall 40, the top surface or top portion 50 of the plume 148 forms waves or turbulence, causing the plume 148 to burn as an upper plume. The turbulence increases the amount of air entering the cavity of the top surface or top portion 50 of the plume 148 or upper plume, which aids combustion and forms a superior air-fuel mixture with improved compression performance. Combustion occurs on the top surface or top portion 50 and the sides of the plume 148 (i.e., the upper plume within the target sidewall 40). The bottom portion 51 of the plume 148 remains in contact with the piston bowl surface 15, preventing air or oxygen from being introduced between the bottom portion 51 of the plume 148 and the piston bowl surface 15. The bottom portion 51 of the plume 148 flows along the piston bowl surface 15, but air cannot reach the bottom portion 51 of the plume 148. Because it is necessary to prevent air and / or oxygen from reaching the bottom portion 51 of the plume 148, the target sidewall 40 is configured to prevent combustion at the bottom portion 51 of the plume 148. This prevents combustion at the bottom portion 51 of the plume 148, while combustion will occur on the top surface or top portion 50 of the plume 148 and on either side of the top surface or top portion 50. Because the hot combustion gases do not contact the piston 12, the heat loss of the piston 12 is lower during this period, thereby improving efficiency. Furthermore, the slower combustion rate in this stage helps reduce NOx production.

[0031] exist Figure 1 In the middle, the target sidewall 40 has an annular first sidewall portion 42, which has a length extending downward and radially outward from the first separating edge or steep edge 35 to an inflection point 45 measured relative to the central axis CA. Figure 1 In the middle, the first sidewall portion 42 is concave. Figure 2In the middle, the first sidewall portion 42 includes a vertical portion 43 that extends downward from the first separating edge or steep flange 35 to a flat portion 49, the flat portion having a greater than Figure 1 The first sidewall portion 42 has a smaller curvature. Figure 3 In the middle, the first sidewall portion 42 has a greater than Figure 1 The first sidewall portion 42 has a more rounded bowl shape and greater curvature. In any embodiment, the first sidewall portion 42 is located horizontally below the central bottom portion 32 as measured relative to the central axis CA. The first sidewall portion 42 has a slope 47 that differs from the central slope 34. The slope change from the central slope 34 to the slope 47 at the first separation edge or steep edge 35 increases turbulence and enables a better fuel-air mixture. The slope change from the central slope 34 to the slope 47 at the first separation edge or steep edge 35 does not cause the fuel to deviate from the first sidewall portion 42, as illustrated by arrow 54. The momentum of the fuel causes it to continue to contact and flow along the first sidewall portion 42, as illustrated by arrow 54.

[0032] Inflection point 45 defines the lowest level of piston cup 14 measured relative to the central axis CA. Inflection point 45 can be a point or region of piston cup 14 where the slope of target sidewall 40 changes from a downward or negative slope measured relative to the central axis CA to an upward or positive slope. The change in slope direction at inflection point 45 affects the momentum direction of fuel 48, as indicated by arrow 60. The momentum of fuel 48 remains in contact with target sidewall 40 at inflection point 45.

[0033] The target sidewall 40 also has an annular second sidewall portion 44, which has a length extending upward and radially outward from the inflection point 45 to the second separation edge or steep edge 46. A portion of the length of the second sidewall portion 44 is concave, and then extends in a near-vertical direction, such as at an angle of 70 to 90 degrees relative to the central axis CA to the second separation edge or steep edge 46. The second sidewall portion 44 has a slope 51 that differs from the slope 47 of the first sidewall portion 42. Slope 51 is a positive slope. The momentum of the fuel causes it to continue contacting and flowing along the second sidewall portion 44, as indicated by arrows 62 and 64.

[0034] As the plume 148 continues to flow along the target sidewall 40 and reaches the second separation edge or steep edge 46, the entire plume 148 detaches from the target sidewall 40 at the second separation edge or steep edge 46 to extend vertically above the second separation edge or steep edge 46. The second separation edge or steep edge 46 is configured such that the entire plume 148 ignites and detaches from contact with the second separation edge or steep edge 46, as illustrated by the detachment area or location 53 and arrows 70, 72, 74, and 76. The second separation edge or steep edge 46 is the detachment area or location 53 that controls the hot spot location on the cylinder head 16. The second separation edge or steep edge 46 controls the peak combustion rate by using more available air around the plume 148. The second separation edge or steep edge 46 is between 70 and 90 degrees relative to the central axis CA. The plume 148 extends vertically toward the cylinder head 16. The plume 148 does not extend toward the cylinder liner (not illustrated). The bottom portion 51 of the plume 148, originally located on the target sidewall 40, is now vertical and exposed to air and oxygen, thus undergoing combustion. The top surface or top portion 50 of the plume 148, previously exposed to air, continues to be exposed to air and undergoes combustion. The second separation edge or steep edge 46 indicates the combustion peak of the plume 148. The second separation edge or steep edge 46 allows the plume 148 to receive more air or oxygen from all sides, i.e., air. As the plume 148 detaches or leaves the second separation edge or steep edge 46 at the detachment area or position 53, the reaction ratio, or fuel-air ratio, is improved. During this period, the piston 12 also moves downward. The detached fuel plume 148 will mix with fresh oxygen from the compression zone, and the combustion rate will reach its peak at this time. After impacting the cylinder head 16, the plume 148 will continue to move in a tumble motion (as illustrated by arrows 72, 74, and 76) due to spray momentum, which contributes to soot oxidation.

[0035] The timing of the combustion peak is controlled by the second separation edge or steep edge 46. The combustion peak can be controlled by moving the second separation edge or steep edge 46 closer to or further away from the first separation edge or steep edge 35. If the second separation edge or steep edge 46 is further away from the first separation edge or steep edge 35, resulting in a longer target sidewall 40, the combustion peak will be delayed more. If the second separation edge or steep edge 46 is closer to the first separation edge or steep edge 35, the combustion peak will occur earlier because the target sidewall 40 is shorter, resulting in less delay. The combustion peak is optimized by moving the second separation edge or steep edge 46 relative to the first separation edge or steep edge 35, thereby shortening or lengthening the target sidewall 40. The combustion peak also affects NOx (i.e., nitric oxide and / or nitrogen dioxide) emissions, therefore the piston cup profile needs to be optimized to minimize NOx emissions at the end of the cycle and / or to ensure that NOx emissions within the combustion chamber 18 are almost completely oxidized.

[0036] The piston cup 14 includes an upper sidewall portion 80 that surrounds a second separating edge or steep flange 46 and has a length of an annular edge 28 extending from the second separating edge or steep flange 46 to the annular top surface 26. The length and slope of the upper sidewall portion 80 can vary.

[0037] exist Figure 4 (A schematic diagram of multiple piston cups 14a to 14i) shows that each of the piston cups 14a to 14i has a piston cup surface 15a to 15i that forms a piston cup profile, which is rotationally symmetrical about a central axis CA and extends from the central axis CA to annular edges 28a to 28i. The piston cup profile controls the compression ratio and peak combustion. Each of the multiple piston cups 14a to 14i also includes a first separating edge or steep flange 35a to 35i and a second separating edge or steep flange 46a to 46i. Target sidewalls 40a to 40i are located between the first separating edge or steep flange 35a to 35i and the second separating edge or steep flange 46a to 46i, respectively. The position of the first separating edge or steep flange 35a to 35i can be 10% to 75% of the radius of the piston cups 14a to 14i. For the corresponding piston cup profile, as the position of the first separating edge or steep edge 35a to 35i moves further away from the central axis CA, the spray angle A1 will also change and increase, thereby avoiding contact with the first separating edge or steep edge 35a to 35i. The position of the second separating edge or steep edge 46a to 46i can be 50% to 90% of the radius of the piston cup 14a to 14i. The radius of the second separating edge or steep edge 46a to 46i is higher than the radius of the first separating edge or steep edge 35a to 35i. The length of the target sidewall 40a to 40i depends on the positions of the first separating edge or steep edge 35a to 35i and the second separating edge or steep edge 46a to 46i, respectively.

[0038] Various aspects of this disclosure are contemplated as will be apparent from the accompanying drawings and text presented above.

[0039] Various aspects of this application are envisioned. According to one aspect, a piston for reciprocating motion within a cylinder in an internal combustion engine, the piston comprising: a piston body having an upper end opposite a lower end, a central axis extending between the upper end and the lower end, wherein the upper end includes an annular top surface defining an upper plane, the upper end including a piston cup recessed relative to the upper plane defined by the annular top surface, wherein the piston cup includes a piston cup surface having a semi-sectional profile including: a central bottom portion, the central bottom portion... A portion extends radially from the central axis to a first separation steep edge with a central slope that is negative relative to the central axis; wherein the first separation steep edge is defined by the intersection of the central bottom portion and the target sidewall; wherein the target sidewall extends between the first separation steep edge and the second separation steep edge, wherein the target sidewall extends with a slope different from the central slope, and the target sidewall is configured to receive fuel from the injector; and wherein the second separation steep edge extends with a slope that is positive relative to the central axis to guide fuel away from the second separation steep edge.

[0040] In one embodiment, the piston bowl has a bowl radius defined between the central axis and the annular top surface, wherein the first separation flange is located between 10% and 75% of the bowl radius.

[0041] In one embodiment, the piston bowl has a bowl radius defined between the central axis and the annular top surface, wherein the second separation flange is located between 50% and 90% of the bowl radius.

[0042] In one embodiment, the target sidewall includes an annular first sidewall portion having a length extending radially outward from the first separating edge to an inflection point measured relative to the central axis.

[0043] In one embodiment, the first sidewall portion includes a vertical portion that extends from the first separating edge to the inflection point.

[0044] In one embodiment, the first sidewall portion is located below the central bottom portion as measured relative to the central axis.

[0045] The piston according to claim 4, wherein the first sidewall portion has a slope different from the central slope.

[0046] In one embodiment, the inflection point defines the lowest point of the piston bowl surface as measured relative to the central axis.

[0047] In one implementation, the inflection point represents the change in the slope direction of the target sidewall measured relative to the central axis from a negative slope to a positive slope.

[0048] In one embodiment, the target sidewall includes an annular second sidewall portion having a length extending from the inflection point to the second separation edge.

[0049] In one embodiment, the second sidewall portion extends from the central axis at an angle between 70 and 90 degrees.

[0050] In one embodiment, the second sidewall portion has a positive slope relative to the central axis.

[0051] According to another aspect, a piston for an internal combustion engine includes: a piston body having an upper end opposite to a lower end, a central axis extending between the upper end and the lower end, wherein the upper end includes a piston cup surface defining a piston cup profile that is rotationally symmetrical about the central axis and extends from the central axis to an annular edge, wherein the piston cup profile includes a target sidewall extending between a first separation flange and a second separation flange, wherein the target sidewall is configured to receive fuel from an injector at a spray angle such that a fuel spray flows across the first separation flange.

[0052] In one embodiment, the spray angle differs from the angle at which the fuel spray is aligned to contact the first separation edge by about 0.5° to about 5°.

[0053] The piston according to claim 13, wherein the second sidewall portion extends from the central axis at an angle between 70 and 90 degrees.

[0054] In one embodiment, the piston cup profile includes a central bottom portion that extends radially from the central axis to a first separation flange with a central slope that is negative relative to the central axis.

[0055] In one embodiment, the target sidewall includes an annular first sidewall portion having a length extending radially outward from the first separation edge to an inflection point measured relative to the central axis, and the target sidewall includes an annular second sidewall portion having a length extending from the inflection point to the second separation edge.

[0056] In one embodiment, the inflection point defines the lowest level of the piston bowl as measured relative to the central axis.

[0057] In one embodiment, the piston bowl has a bowl radius, wherein the first separation flange is located between 10% and 50% of the bowl radius.

[0058] In one embodiment, the piston bowl has a bowl radius, wherein the second separation flange is located between 50% and 75% of the bowl radius.

[0059] In the above description, certain relative terms such as "up," "down," "above," "below," "horizontal," "vertical," "left," "right," "near," and "far" may be used. Where applicable, these terms are used to provide a clear description when dealing with relative relationships. However, these terms are not intended to imply absolute relationships, positioning, and / or direction. For example, for an object, simply flipping the object can turn the "upper" surface into the "lower" surface. However, it is still the same object.

[0060] Throughout this specification, the terms "an embodiment," "implementation," or similar language mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of this disclosure. The phrases "in one embodiment," "in an embodiment," and similar language appearing throughout this specification may, but not necessarily all, refer to the same embodiment. Similarly, the term "specific implementation" is used to mean a specific implementation having a particular feature, structure, or characteristic described in connection with one or more embodiments of this disclosure; however, unless otherwise explicitly indicated by a specific relevance, a specific implementation may be associated with one or more embodiments.

[0061] The features, structures, advantages, and / or characteristics described in this disclosure can be combined in any suitable manner in one or more embodiments and / or specific implementations. Numerous specific details are provided in the following description to provide a thorough understanding of embodiments of the subject matter of this disclosure. Those skilled in the art will recognize that the subject matter of this disclosure can be practiced without one or more of the specific features, details, components, materials, and / or methods of a particular embodiment or specific implementation. In some cases, the benefit of simplicity can lead to operational and economic benefits, and the exclusion of certain elements described herein is contemplated as being for the inventors to realize such benefits within the scope of the invention. In other instances, additional features and advantages may be recognized in some embodiments and / or specific implementations and are not present in all embodiments or specific implementations. Furthermore, in some cases, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring various aspects of the subject matter of this disclosure. The features and advantages of the subject matter of this disclosure will become more apparent from the following description and the appended claims, or may be learned by practicing the subject matter listed below.

[0062] This subject matter may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments should be considered illustrative rather than restrictive in all respects. Therefore, the scope of the invention is indicated by the appended claims, not by the foregoing description. All modifications within the equivalent meaning and scope of the claims should be included within their scope.

Claims

1. A piston for reciprocating within a cylinder in an internal combustion engine, the piston comprising: A piston body having an upper end opposite to a lower end, and a central axis extending between the upper and lower ends. The upper end includes an annular top surface defining an upper plane, and a piston cup recessed relative to the upper plane defined by the annular top surface. The piston cup includes a piston cup surface having a half-section profile, the half-section profile comprising: A central bottom portion, which extends radially from the central axis to a first separation steep edge with a central slope that is negative relative to the central axis; The first separation edge is defined by the intersection of the central bottom portion and the target sidewall; The target sidewall extends between the first and second separation flanges, and the target sidewall extends with a slope different from the center slope, the target sidewall being configured to receive fuel from the injector; and The second separation flange extends with a slope that is positive relative to the central axis to guide fuel away from the second separation flange.

2. The piston of claim 1, wherein the piston cup has a cup radius defined between the central axis and the annular top surface, wherein the first separation flange is located between 10% and 75% of the cup radius.

3. The piston of claim 1, wherein the piston cup has a cup radius defined between the central axis and the annular top surface, wherein the second separation flange is located between 50% and 90% of the cup radius.

4. The piston of claim 1, wherein the target sidewall includes an annular first sidewall portion having a length extending radially outward from the first separation flange to an inflection point measured relative to the central axis.

5. The piston of claim 4, wherein the first sidewall portion includes a vertical portion extending from the first separating flange to the inflection point.

6. The piston of claim 4, wherein the first sidewall portion is located below the central bottom portion measured relative to the central axis.

7. The piston of claim 4, wherein the first sidewall portion has a slope different from the central slope.

8. The piston of claim 4, wherein the inflection point defines the lowest point of the piston cup surface as measured relative to the central axis.

9. The piston of claim 8, wherein the inflection point represents the change in the slope direction of the target sidewall, measured relative to the central axis, from a negative slope to a positive slope.

10. The piston of claim 4, wherein the target sidewall includes an annular second sidewall portion having a length extending from the inflection point to the second separation flange.

11. The piston of claim 10, wherein the second sidewall portion extends from the central axis at an angle between 70 and 90 degrees.

12. The piston of claim 10, wherein the second sidewall portion has a positive slope relative to the central axis.

13. A piston for an internal combustion engine, the piston comprising: A piston body having an upper end opposite a lower end, a central axis extending between the upper and lower ends, wherein the upper end includes a piston cup surface defining a piston cup profile that is rotationally symmetrical about the central axis and extends from the central axis to an annular edge. The piston cup profile includes a target sidewall that extends between a first separation flange and a second separation flange, wherein the target sidewall is configured to receive fuel from the injector at a spray angle such that the fuel spray flows over the first separation flange.

14. The piston of claim 13, wherein the spray angle differs from the angle at which the fuel spray is aligned to contact the first separation flange by about 0.5° to about 5°.

15. The piston of claim 13, wherein the second sidewall portion extends from the central axis at an angle between 70 and 90 degrees.

16. The piston of claim 13, wherein the piston cup profile includes a central bottom portion extending radially from the central axis to a first separation flange with a central slope that is negative relative to the central axis.

17. The piston of claim 13, wherein the target sidewall includes an annular first sidewall portion having a length extending radially outward from the first separation flange to an inflection point measured relative to the central axis, and the target sidewall includes an annular second sidewall portion having a length extending from the inflection point to the second separation flange.

18. The piston of claim 17, wherein the inflection point defines the lowest level of the piston cup as measured relative to the central axis.

19. The piston of claim 13, wherein the piston cup has a cup radius, and wherein the first separation flange is located between 10% and 75% of the cup radius.

20. The piston of claim 13, wherein the piston cup has a cup radius, and wherein the second separation flange is located between 50% and 90% of the cup radius.

Images