Piston pin, piston, connecting rod-piston pin-piston assembly, and method of operation

Abstract

A piston (40) for use in a cylinder of an internal combustion engine, the piston comprising a cylindrical body (41) defining a piston crown (42) and at least a first skirt portion (47, 48) depending from the piston crown (42) in use, the skirt portion defining a hollow space (49) and supporting at least one piston pin journal (51, 52) in the space (49) for receiving a piston pin (30) therein, the piston (40) comprising at least a first piston oil feed passage (56) formed in the piston for feeding pressurised oil from the hollow space (49) to the first skirt portion (47), the hollow space (49) comprising an inner opening (61) of the piston oil feed passage (56), and the piston oil feed passage terminating at or proximate to an outer surface of the first skirt portion (47) at an outer opening (58).

Description

Technical Field

[0001] This invention relates to a piston pin, a piston, and assemblies of these components with connecting rods as part of an internal combustion engine. The invention also relates to methods of operation when these components are assembled together. Background Technology

[0002] As is well known, the internal combustion engine has undergone continuous development since its invention at the end of the 18th century and its industrial application from the 19th to the 21st century.

[0003] The internal combustion engine is a highly successful product with extremely wide applications. In the UK alone, an estimated 33.5 million passenger cars are in service, the vast majority of which are powered by spark-ignition or compression-ignition internal combustion engines—terms familiar to those skilled in the art. In both spark-ignition and compression-ignition internal combustion engines, the two-stroke and four-stroke operating modes are well-known.

[0004] In addition, industrialized economies have millions of light commercial vehicles (LGVs), heavy-duty commercial vehicles (HGVs), motorcycles, scooters, ambulances, buses / buses, other land vehicles (including trains, snowmobiles, snow sleds, go-karts, ATVs, and special vehicles such as agricultural, garbage collection, firefighting, construction, mining, and military vehicles), and water vehicles such as ships, small boats, hovercraft, and motorboats, most of which are powered by internal combustion engines. Internal combustion engines have also been used in many aircraft, particularly light aircraft manufactured before approximately the early 1990s; and in some helicopters, where opposed-cylinder and radial cylinder designs are known.

[0005] While the most common application of internal combustion engines is in vehicles, these types of engines are also used in many machines that do not have a primary transportation function but are stationary or have only a limited range of travel. Therefore, internal combustion engines are widely used in pumps, auxiliary power units, and generators, as well as in domestic or estate machinery such as lawnmowers, garden / estate tractors, leaf blowers, brush cutters, pressure washers, log splitters, and chainsaws. Other exemplary applications of internal combustion engines are in stationary or largely immobile machines such as dredging platforms, power shovels, and dragline excavators.

[0006] For roughly two centuries, the internal combustion engine has been the subject of extensive academic research and practical development. Despite this research and the widespread adoption of internal combustion engine technology, some of its shortcomings remain unresolved. In certain cases, these shortcomings become even more pronounced as demands for engine power output and efficiency continue to increase.

[0007] One of the drawbacks involves vibration, overheating, and wear of the piston skirt, which is an essential component of an internal combustion engine.

[0008] An internal combustion engine piston is a cylindrical metal component that reciprocates longitudinally within a cylinder bore formed in the engine block or a similarly functional part of the engine. The piston and cylinder bore are carefully designed so that the piston forms a sliding fit within the cylinder bore while providing a substantially sealed space at one of the substantially closed ends of the cylinder bore, commonly referred to as the "combustion chamber." The sealing of the combustion chamber is typically achieved in a manner well known to those skilled in the art, by means of two or more compression rings disposed in grooves on the outer surface of the piston; these compression rings have a diameter larger than that of the piston itself. Oil control rings—their nature also well known—are disposed in another groove on the outer surface of the piston to scrape away a relatively small amount of oil that accumulates on a portion of the cylinder adjacent to a section of the piston known as the "skirt," located on the side of the piston opposite the combustion chamber.

[0009] The reciprocating motion of the piston is caused by the periodic deflagration of a mixture of flammable fuel and air in a combustion chamber adjacent to one end of the piston. The force of this deflagration, especially the rapid expansion of the combustion gases produced, acts primarily on the part called the piston, known as the top, to drive the piston along the cylinder bore away from the deflagration point.

[0010] The piston's diameter near the top is typically slightly smaller than the skirt's diameter. As previously mentioned, the compression rings create the necessary seal to ensure the detonation energy of the fuel / air mixture acts on the piston. The skirt's diameter is slightly larger than the top's diameter; the skirt is the part of the piston intended to form a sliding fit within the cylinder during reciprocating piston motion. As explained below, the skirt's direct metal-to-metal contact with the cylinder wall—as seen in prior art engines—presents problems in several ways.

[0011] After the knock-up generates pulse energy, at least one (or more in most engines) valve in the cylinder bore opens to allow exhaust gases to be swept out of the cylinder and refilled with a larger air / fuel mixture of the desired composition.

[0012] The movement of the piston is converted into rotational motion by a combination of piston pins (sometimes called trunnions in the UK) and a rigid, elongated connecting element called a connecting rod. The piston pins are held in pairs of laterally spaced piston pin seats that define laterally spaced journals adjacent to the top of the piston. The connecting rod is pivotally connected to the piston pins at one end.

[0013] The connecting rod is pivotally connected to the crankshaft at its opposite end—often called the crankpin end. Due to the pivoting connection and the rigidity of the connecting rod, the longitudinal reciprocating motion of the piston typically becomes an irregular trajectory in the connecting rod, but becomes rotational motion in the crankshaft (which is supported at least at its ends by swivel bearings).

[0014] The shape of the crankshaft, during its rotation, causes the piston to reciprocate toward the point of combustion in the cylinder under the influence of the return force transmitted by the connecting rod after detonation. This effect is enhanced in many engines by the action of a flywheel connected to the crankshaft and increasing its rotational inertia.

[0015] When the piston reaches the detonation point again, a new round of fuel / air mixture combustion occurs, driving the piston back along the cylinder. As is well known, in a two-stroke engine, detonation occurs each time the piston returns to the closed end of the combustion chamber. In a four-stroke engine, detonation occurs each time the piston alternately reaches the detonation position. Depending on the engine type, detonation may be caused by a timed spark (spark ignition engine) or by air heating (generated by compression caused by piston movement), which occurs simultaneously with the fuel injection into the combustion chamber (compression ignition engine).

[0016] The movement of the piston, connecting rod, and crankshaft cycles in most examples, repeating several times per second, as long as necessary, unless the combustible fuel supplied to the cylinders is exhausted or measures are taken to shut down the engine.

[0017] Internal combustion engines can comprise an assembly of a single piston, piston pin, and connecting rod; or multiple sets of these components spaced apart from each other within the engine. Modifications to accommodate multiple pistons are well-known.

[0018] In multi-cylinder engines, the crankshaft design synchronizes the movement of multiple pistons in each cylinder. A control system, an integral part of the engine, ensures that combustion near the pistons is also properly timed. The overall effect is a smooth sequence of combustion and piston movement, thereby optimizing engine power output and minimizing harmonic oscillations, noise, other forms of energy waste, and component wear.

[0019] In so-called "inline" and V-shaped designs, the crankshaft typically extends horizontally, usually located at or near the bottom of the engine's hollow interior. In, for example, opposed-cylinder engines (also known as "horizontal" or "boxer" engines), the crankshaft is located roughly in the center of the engine.

[0020] Regardless of its location, the crankshaft or the components connected to it protrude from the crankcase that houses the crankshaft. Due to this protrusion, the rotational motion of the crankshaft can serve as the rotational output of the engine and (in many cases) is supplied in a controlled manner via one or more clutches and gear sets to drive, for example, the rotatable ground-engaged wheels or tracks of a vehicle, or other output elements in other types of machinery.

[0021] The smallest internal combustion engines, such as those used in some types of garden machinery, can produce less than 1 kilowatt of power output, while the most powerful (such as those used in various forms of racing cars, speedboats, heavy trucks, and construction, agricultural, and mining machinery) can produce hundreds of kilowatts, or in some cases, more than 1 megawatt of output. Furthermore, some ships are powered by very large internal combustion engines with outputs reaching tens of megawatts. However, all internal combustion engines generate a significant amount of heat relative to their size, a result of fuel detonation and combustion; friction from the various moving parts of the engine; and, in the case of compression ignition engines, the intentional rapid compression of air to induce the desired fuel detonation.

[0022] Most of the heat generated by an internal combustion engine is undesirable, except for the portion intentionally generated in compression ignition engines. A relatively small amount of the heat generated can be recovered in the vehicle for comfort heating and windshield defogging purposes. The remainder is potentially harmful. This is partly because engine efficiency can decrease if it does not operate at optimal temperatures related to the materials used to manufacture the engine and the composition of the fuel / air mixture.

[0023] Furthermore, if overheated, the metal components used in manufacturing the engine may deform or undergo undesirable heat treatments. In severe cases, these effects can reduce efficiency or cause permanent damage to the engine. Such damage can manifest as catastrophic engine failure. This is highly undesirable for various cost / economic and inconvenience reasons; and in some cases, it poses a significant hazard to human safety.

[0024] Given these factors, internal combustion engines typically require cooling. In many designs, this is achieved in part by allowing a cooling medium, such as water or air, to flow through and dissipate heat from the various parts of the engine. Lubricants, formulated to ensure smooth and efficient sliding of the various moving parts within the engine, are also designed with specific thermal properties. Therefore, engine lubricants play an important additional role in removing unwanted heat from the various components.

[0025] In many engines, this liquid form of lubricant is pumped through a flow circuit by a rotary pump. The pump is driven by drawing rotational energy directly or indirectly from a camshaft, for example, that operates the aforementioned valve. The pump includes a pickup tube, which is open at one end and immersed in an oil pan (or another lubricant), which in many engines is located below the crankshaft.

[0026] The location of the oil pan and the structure of the crankshaft dictate that the flow path is designed so that the bearings at the crankpin ends of the connecting rod are lubricated relatively directly by pumped oil. This allows the crankpins, which form part of the crankshaft, to be effectively lubricated, cooled, and supported in a manner known as "floating." This term implies that the crankpins are supported and surrounded by pressurized lubricant during use, which is pumped between the crankpins and the bearing inserts, which form part of the pivotal connection between the crankpin ends of the connecting rod and the crankshaft.

[0027] The effect of this is that, despite the various forces experienced by the crankpin during engine operation, the lubricant can evenly support at least a portion of the crankpin's circumference. The lubricant's ability to support the crankpin stems from the fundamental incompressible nature of fluids such as lubricants.

[0028] On the other hand, the position and design of the piston and its attached components mean that it is practically impossible to pump liquid lubricant to the piston skirt in existing engine designs. Instead, a limited amount of lubricant is flushed onto the skirt from the oil control ring using splash or jet techniques. The oil control ring includes recesses that distribute a thin layer of oil scraped from inside the cylinder as the piston reciprocates.

[0029] Given that the piston needs to slide back and forth repeatedly along the cylinder bore, and the skirt is expected to contact or come very close to the cylinder wall, this limited lubrication of the piston skirt is a disadvantage.

[0030] In particular, oil splash / jet technology does not allow for floating lubrication of the piston skirt because it does not provide a pressurized supply to the skirt surface. The lubricant distributed by the control ring is in a very small volume and is also unpressurized. Therefore, the lubricant has a negligible effect on the piston skirt.

[0031] Inadequate piston skirt lubrication in current engine designs means that the piston, especially if wear causes the skirt to not have a tight sliding fit within the cylinder, may oscillate during reciprocating motion, such as by swaying left and right or according to complex harmonic patterns. This leads to unwanted contact with the cylinder wall and accelerates skirt wear. Skirt wear, in turn, exacerbates the oscillation problem.

[0032] Furthermore, the ability of splashed or sprayed lubricant to dissipate heat from the piston skirt is limited.

[0033] Piston manufacturers sometimes apply a heat-bonded or otherwise bonded layer to the piston skirt surface to counteract skirt wear caused by piston oscillation in the cylinder bore.

[0034] However, the applicant's investigation revealed that such surface coatings typically only last a short time in practice. This is a result of the sliding contact between the piston skirt and cylinder wall in existing engines. Therefore, these coatings, for example, in high-performance (such as racing cars) or high-torque (such as construction or mining machinery) engines, can wear off after only a few minutes. When this happens, the coating cracks, leading to a reduction in the skirt diameter, and making, for example, piston swaying more likely. This, in turn, means increased contact between the skirt metal and the cylinder wall, which is highly detrimental. Furthermore, particles from the worn coating become contaminants in the lubricant.

[0035] These coatings can be expensive, so they are rarely used in low-cost engines. Furthermore, using these coatings does nothing to address the need to dissipate heat from the piston skirt.

[0036] One sector where insufficient piston skirt lubrication causes significant economic damage is the mining industry. In this industry, very large machines such as dragline excavators, power shovels, rotary excavators, bucket wheel excavators, and heavy-duty trucks often include internal combustion engines with large-diameter cylinders and pistons. These machines are highly susceptible to unwanted vibrations, leading to premature wear of the piston skirt. This wear means that engines in such machines typically require multiple overhauls per year. In addition to the resulting downtime costs, pistons and compression rings are often discarded during overhauls. Therefore, engine overhauls are somewhat wasteful, despite the high cost of large and / or high-performance pistons, their potential for being made of highly alloyed materials, and their frequent supply shortages.

[0037] Another example of an engine where piston wear leads to frequent overhauls is a racing engine, such as those used in race cars, racing motorcycles, or speedboats. In these engines, the extremely high reciprocating speeds cause the pistons to wear out relatively quickly.

[0038] Even internal combustion engines with relatively slow reciprocating motion, such as those used in some ships, require major overhauls, for example, every two to three years (the anticipated wear of pistons and related rings is a major determinant of overhaul schedules). Taking large ships out of service to rebuild their engines can be extremely expensive. Summary of the Invention

[0039] The purpose of this invention is to solve or at least mitigate one or more disadvantages of related technologies.

[0040] According to a first aspect of the invention, a piston pin for an internal combustion engine is provided, the piston pin being a rigid and elongated cylindrical member having formed therein: at least one first piston pin oil supply passage extending from a first piston pin opening located on the outer surface of the cylindrical member to an end adjacent to the diameter center of the piston pin, the first piston pin opening preferably, but not necessarily, located approximately halfway along the length of the outer surface of the cylindrical member; and at least one second piston pin oil supply passage extending from the end of the first piston pin oil supply passage toward another piston pin opening located on the outer surface of the cylindrical member, the other piston pin opening being spaced apart from the first piston pin opening along the length of the cylindrical member, the first piston pin oil supply passage and the second piston pin oil supply passage being in fluid communication with each other at or near their ends to allow fluid to flow from the first piston pin opening along the first piston pin oil supply passage to the end, and then along the second piston pin oil supply passage to the other piston pin opening.

[0041] This piston pin advantageously allows for a pressurized supply of liquid lubricant, flowing from, for example, the longitudinal central region of the piston pin toward its ends. This, in turn, allows for a pressurized supply of lubricant from the longitudinal midpoint of the piston pin to the vicinity of the piston pin seat of the attached piston. Therefore, when pressurized lubricant is supplied via the connected connecting rod, the piston pin according to the invention enables a floating support of the piston pin relative to the attached piston. Compared to piston pins lubricated by related techniques, this significantly improves the efficiency, cooling effect, and service life of the piston pin.

[0042] According to a second aspect of the invention, a piston for use in a cylinder of an internal combustion engine is provided. The piston includes a cylindrical body defining a piston top and at least one first skirt portion. One or more first skirt portions hang from the piston top in use. The skirt portions define a hollow space and support at least one piston pin journal within the space. The piston pin journal is used to receive a piston pin. At least the first skirt portion includes a piston oil supply passage formed therein for supplying pressurized oil from the hollow space to the first skirt portion. The hollow space includes an internal opening of the piston oil supply passage, and the piston oil supply passage terminates at or near an external opening located on or near the outer surface of the first skirt portion. In an embodiment, the oil supply passage allows pressurized oil to be supplied from the portion of the hollow space supporting the piston pin journal to the outer surface of the first skirt portion.

[0043] In many practical implementations, pairs of piston pin journals spaced apart from each other are preferably provided, but implementations may also be provided, for example, with only a single piston pin journal.

[0044] Advantageously, the piston described herein can pressurize and supply lubricant, such as oil, from the piston's interior to the outer surface of the skirt. This, for the first time, allows the skirt and the entire piston to be floatingly supported in such a way as to: (a) dampen unwanted piston oscillations; (b) lubricate the piston's sliding motion; and (c) conduct heat away from the piston as the piston's reciprocating motion wipes the lubricant away from the skirt. This floating support of the skirt makes piston movement more efficient by eliminating piston oscillations and also significantly reduces wear, thereby extending the piston's vibration-free life. Furthermore, a coating on the piston skirt is no longer required, thus reducing costs and avoiding problems caused by coating wear.

[0045] The pistons defined in this article are particularly beneficial in engine designs where piston wear caused by contact with the cylinder walls has so far resulted in the need for regular overhauls, as described in this article.

[0046] As mentioned earlier, the usual practice during major overhauls of this type of engine is to discard worn pistons. This represents a significant loss of engineered components, which can be significantly reduced or even eliminated entirely by using pistons according to the embodiments described herein.

[0047] This article discloses a connecting rod for an internal combustion engine. The connecting rod includes a crankpin end, a small end, and a longitudinally extending rod rigidly connecting the crankpin end and the small end. The rod has an internal connecting rod oil supply passage along its length. The connecting rod oil supply passage includes a crankpin end opening and a small end opening located at the crankpin end and the small end, respectively. Oil supplied to the connecting rod oil supply passage under pressure at the crankpin end is transported along the connecting rod oil supply passage to flow out at the small end under pressure.

[0048] The advantage of this connecting rod is that, when used in conjunction with the pressurized lubricant supply of the crank pin bearing assembly, the connecting rod allows pressurized lubricant to be supplied along the length of the connecting rod to the gallery located at the small end.

[0049] The first and second aspects of the invention can be combined with each other and with the connecting rod assembly described herein to define an assembly of connecting rod, piston pin and piston according to the third aspect of the invention—as defined in claim 12 herein.

[0050] In particular, in such an assembly, the various openings forming lubricant supply channels can be arranged to be aligned with each other or with one or more pressurized lubricant reservoirs at at least some points during the reciprocating motion of the components. This means that a repeatedly replenished, or more preferably continuous, supply of pressurized lubricant can be supplied to the outer surface of the skirt, thereby ensuring that floating lubrication, and / or support and / or vibration damping, and / or cooling effects are generated in a substantially constant manner. Clearly, in view of this, the piston pin and piston defined herein can be considered as inventive sub-components of the inventive assembly comprising the connecting rod, piston pin, and piston; or the piston pin and piston can be considered as inventive on their own, since they offer advantages even if they do not constitute part of the aforementioned assembly.

[0051] In the components described herein, the piston pin may be fixed relative to the connecting rod and be pivotable only relative to the piston; or it may be pivotable relative to both the connecting rod and the piston.

[0052] According to a fourth aspect of the invention, a method as defined in claim 18 herein is provided. The advantages of this method are as described above with respect to connecting rods, piston pins, pistons, and assemblies. In particular, the method disclosed herein is widely applicable to various internal combustion engine designs and solves long-standing problems related to piston skirt lubrication, cooling, and stabilization / vibration damping. The method of the invention is preferably implemented using the apparatus defined herein.

[0053] According to a fifth aspect of the invention, a manufacturing method as defined in claim 19 herein is provided. This method can advantageously be implemented for newly manufactured pistons or as a modification of existing pistons, thereby allowing the invention to be applied as a retrofit option in existing engines.

[0054] Optional features of various aspects of the invention are defined in the dependent claims herein. A particularly important optional feature is a recessed oil distribution groove formed in the outer surface of the piston skirt, extending around a portion of the skirt's periphery, with an external opening leading to the recessed groove. These features ensure a continuous and adequate supply of lubricant to the piston skirt.

[0055] For the avoidance of doubt, the terms “oil” and “lubricant” are used essentially synonymously herein, referring to a flowable medium, preferably but not necessarily a liquid, capable of performing the floating support and / or vibration damping and / or lubrication and / or cooling functions as explained herein, and capable of being pressurized as described herein.

[0056] The various aspects of this invention and the embodiments described herein can be used in almost all types of internal combustion engines, including but not limited to those specifically mentioned herein. Attached Figure Description

[0057] Preferred embodiments of the invention will now be described by way of non-limiting examples and with reference to the accompanying drawings, in which: Figure 1a This is a schematic isometric view of the link according to this disclosure; Figure 1b yes Figure 1a An enlarged isometric view of region A; Figure 2a and Figure 2b Is with Figure 1a and Figure 1b Similar isometric views show various features that are usually hidden, indicated by dashed lines. Figure 2b Enlarged to show Figure 2a Region B; Figure 3a and Figure 3b These are isometric external plan views and side views of an embodiment of the piston pin according to this disclosure, with features that are normally hidden shown in dashed lines; Figure 4a , Figure 4b and Figure 4c These are, respectively, an isometric view of the entity viewed from below according to an embodiment of the piston of this disclosure, a similar isometric view showing features that are usually hidden in dashed lines, and a side view; Figure 5 It is an isometric view of a perforated bearing insert that can be used in conjunction with other components described herein; and Figure 6 It is an isometric view of the assembly of connecting rod, piston pin and piston according to this disclosure. Detailed Implementation

[0058] First refer to Figure 1a , Figure 1b , Figure 2a and Figure 2b The diagram illustrates a connecting rod 10 for an internal combustion engine. There are no particular limitations on the engines in which this connecting rod 10 can be used. The engine type and intended use can be any of those mentioned herein, but the invention is particularly suitable (among others) for high-output engines, such as those used in high-performance cars, racing cars, and motorcycles; and for large engines, such as those used in mining machinery and ships. In such engines, the pressurized lubricant supply produced by the present invention is highly beneficial.

[0059] The connecting rod 10 is shown extending vertically upward, an orientation typically adopted when the connecting rod 10 is used in an inline engine (affected by changes in orientation due to movement during use). However, as is well known to those skilled in the art and implied above, different orientations are possible. Thus, when included in, for example, an opposed-cylinder engine, the connecting rod extends generally horizontally; when included in a V-configuration engine, the connecting rod may extend at approximately 30° to 45° (or other angles, depending on the engine design) relative to the vertical; and when included in a radial engine, the connecting rod may again adopt any of the various orientations determined by the engine design.

[0060] In the remainder of this specification, the term "vertical" as used in relation to orientation and dimensions refers to the longitudinal orientation shown in Figures 1 and 2, and derived terms (including prepositions such as "above" and "below") are interpreted accordingly. However, as illustrated, the shown orientation of the components does not limit the invention.

[0061] Furthermore, unless the context requires otherwise, references to a single component herein should be considered to cover multiple examples as contemplated by those skilled in the art. Thus, illustrating, for example, a single connecting rod, wrist pin, and piston does not preclude the application of the invention in engines having more than one such example of a component.

[0062] As is conventional, the connecting rod 10 includes a crank pin end 11, a small end 12, and a rigid, longitudinally extending rod 13 that interconnects the crank pin end 11 and the small end 12. The connecting rod 10 is made of a metal alloy and, in many but not all cases, is formed by a combination of forging and machining, as is conventional. However, other methods of manufacturing the connecting rod 10 are known and fall within the scope of this disclosure.

[0063] Similar to most connecting rod designs, rod 13 tapers from a relatively large width near the crank pin end 11 to a relatively narrow width near the small end 12 in a lateral (left-to-right or right-to-left) sense when viewed from the front, as seen in Figures 1 and 2. Rod 13 also has a reduced dimension in the central portion in the thickness direction orthogonal to the taper direction, as shown, thereby minimizing the amount of metal required to manufacture it.

[0064] The thickness reduction region is in Figure 1a The number 16 is used to denote the link, and the reduced thickness region causes the link 10 to have an I-beam cross-section for most of its length. H-beam cross-sections and other link cross-sections are also well known to those skilled in the art, as are links with other degrees of taper or no taper at all. Fork-end links are also known. The link shapes shown do not limit the scope of this disclosure and cover all mentioned and / or variations that may occur to those skilled in the art.

[0065] like Figure 2a and Figure 2b As best shown in the embodiment, rod 13 has a connecting rod oil supply channel 14 extending internally along its length. The connecting rod oil supply channel 14 includes a crank pin end opening 17 at its lowermost end. This opening leads to an annular portion 18, which forms part of the crank pin end in a conventional connecting rod and rotatably surrounds the crank pin of the crankshaft.

[0066] In a typical vehicle engine connecting rod, the crankpin end is formed into two parts: a rod cap 21 and a forged large end 19 integral with the rod 13. The large end 19 and the rod cap 21 each define a semi-annular portion of an annular portion 18. In the illustrated embodiment, the rod cap is secured to the large end with bolts (omitted from the figures for clarity) that are familiar to those skilled in the art. The bolts secure the rod cap 21 tightly to the large end 19, such that the mating line between the rod cap 21 and the large end 19 is... Figure 1a and Figure 2a It is not visible in the view.

[0067] In some other engine types covered in this disclosure, the entire connecting rod (including the crankpin end) is formed as a single piece. In such engines, the crankshaft is instead composed of multiple sub-components, which are secured together by bolts, for example, when the crankpin is inserted into a hole defined at the crankpin end of the connecting rod. This method of constructing the crankshaft and connecting rod connection is common in, for example, motorcycle engines.

[0068] Regardless of its exact design, the purpose of the construction is to allow the crankpin end 11 to be assembled in a manner that presents a continuous arcuate surface, which defines a circular annular portion 18 surrounding the crankpin. Semi-annular bearing inserts 22, 23 (not visible as separate components in Figures 1 and 2, but actually two semi-shell-like portions) are also generally included and are surrounded by the annular portion 18 created by the shapes of the inner surfaces of the large end 19 and the inner surface of the rod cap 21. A non-limiting example of the design of the bearing insert 22 will be referred to below. Figure 5 describe.

[0069] The connecting rod oil supply channel 14 is opened at its upper end as a small end opening 24 in the inner surface of the annular orifice 26 defined by the small end 12.

[0070] As can be clearly seen from the above, pressurized lubricant, such as oil, near the crankpin end opening 17 can be induced to be supplied upward along the oil supply passage 14, appearing as a pressurized lubricant flow via the small end opening 24. As explained, in many internal combustion engines, the source of pressurized lubricant is located near the crankpin to provide floating support for the crankpin end relative to the connecting rod. Therefore, as a result of the present invention, pressurized lubricant can be supplied to the top of the connecting rod, particularly to the moving portion located within the overhanging portion of the attached piston adjacent to the skirt.

[0071] In the illustrated embodiment, the connecting rod oil supply channel 14 is a straight hole with a circular cross-section. This channel can be easily formed by machining, particularly when the large end 21 is not attached to the crank pin end 11, by drilling and (if necessary) reaming the channel 14. Therefore, the connecting rod oil supply channel 14 can be formed as a modification of an existing connecting rod, and it is not necessary to form the connecting rod oil supply channel 14 during the manufacturing of the connecting rod.

[0072] The connecting rod oil supply channel 14 need not be as uniform as described. Instead, the desired fluid flow effect can be achieved, for example, by varying the diameter and / or cross-sectional shape of the connecting rod oil supply channel 14 along its length and / or by including non-linear deformations of the channel 14. Techniques for forming non-uniform deformations of the connecting rod oil supply channel 14 will be familiar to those skilled in the art.

[0073] Furthermore, it is not necessary for the connecting rod oil supply channel 14 to extend internally through the connecting rod 10. In alternative embodiments, the connecting rod oil supply channel 14 may be located, for example, on the surface of the connecting rod and extend along it in a conduit manner. However, from the perspective of ease of channel formation, resistance, and maintaining the symmetry of the connecting rod 10, it may be preferable to form the connecting rod oil supply channel 14 internally within the rod 13.

[0074] The eyelet 26 is intended to surround the piston pin. In one embodiment, the small end opening 24 is open in the eyelet at a location corresponding to the longitudinal midpoint of the piston pin when it is assembled with the connecting rod 10. However, in some other embodiments, the piston pin may not be longitudinally symmetrically positioned relative to the eyelet 26. Therefore, it is not required in all embodiments that the small end opening be centered along the associated piston pin.

[0075] The inner surface 27 of the eyelet 26 includes a lubricant groove 28 formed therein as an arcuate recess. A small end opening 24 leads into the groove 28.

[0076] The groove 28 can be formed by machining the metal of surface 27, or by various other methods known to those skilled in the art. The groove 28 can serve as a reservoir for lubricant, which is actually pumped into the groove and exits from the small end opening 24 due to the pressurized lubricant supply near the crank pin end 11.

[0077] In the illustrated embodiment, the groove 28 extends as an annular portion surrounding the entire inner surface of the aperture 26. However, this is not mandatory; a groove extending only partially around the inner surface is also possible. Furthermore, the groove 28 does not need to have the constant cross-section shown, nor does it need to present a shape as described. Figure 2a and Figure 2b The example illustrates a straight cross-section. Therefore, the slot 28 can have various sizes and shapes, and the size and shape of the slot 28 can vary at different locations along its length. Furthermore, the slot does not need to be continuous, but can be interrupted, for example, by dividing platforms (land) that divide the slot into groups of sub-slots.

[0078] Now refer to Figure 3a and Figure 3b It shows that it can be used with Figure 1a , Figure 1b , Figure 2a and Figure 2b The embodiment of the piston pin 30 used in conjunction with the connecting rod 10.

[0079] Figure 3a This is the external isometric view of piston pin 30, and Figure 3b It is a side view, showing various (usually obscured) internal features with dashed lines.

[0080] As shown, the piston pin 30 is a rigid cylindrical rod made of metal or a metal alloy (in almost all embodiments). The piston pin 30 in... Figure 3a and Figure 3b The piston pin 30 is elongated in the left-right direction as seen in the image. It can be formed, for example, by machining a metal rod. Many other ways of forming the piston pin 30 are possible, and those skilled in the art will recognize them.

[0081] A hole 31 with a constant circular cross-section is formed centrally in the piston pin 30, extending from one end of the piston pin 30 to the other along its longitudinal axis. The hole 31 can be formed by drilling and reaming the material of the piston pin 30 as needed. However, this method of forming is not limiting, and many other ways of forming the hole 31 are known and contemplated by those skilled in the art.

[0082] The general cylindrical shape of the piston pin 30 and the center hole 31 are conventional in piston pin design.

[0083] At the longitudinal midpoint of the piston pin 30, a first opening 32 is formed on the outer surface of the piston pin 30, which defines the open end of the first piston pin oil supply passage 33.

[0084] In the illustrated embodiment, the first piston pin oil supply channel 33 is a straight, annular, radially extending hole with a constant cross-section for most of its length. The first piston pin oil supply channel 33 can be formed in the material of the piston pin 30 by, for example, drilling or by other feasible techniques conceivable to those skilled in the art. The first piston pin oil supply channel 33 extends towards the lateral center of the piston pin and terminates radially outward at a short distance from the central hole 31. As a result, the first oil supply channel 33 does not communicate with the central hole 31.

[0085] The cross-section, dimensions, and uniformity of the first piston pin oil supply passage 33 can be varied in ways that can be conceived by those skilled in the art.

[0086] At the end of the first piston pin oil supply passage closest to the lateral center of the piston pin 30, the first piston pin oil supply passage terminates at the connecting passage 34. For example... Figure 3b As shown, the connecting channel 34 may optionally have a different cross-section and / or dimensions than the main portion of the first piston pin oil supply channel 33.

[0087] The connecting channel 34 serves as the end of the first piston pin oil supply channel 33 and fluidly connects the first piston pin oil supply channel 33 to the second piston pin oil supply channel 36.

[0088] In the illustrated embodiment, the second piston pin oil supply channel 36 is a straight hole with a constant circular cross-section extending from the connecting channel (end) 34 to a further piston pin opening 37, which is formed in the outer surface of the piston pin at a location spaced apart from the first piston pin opening 32. The cross-section, dimensions, and uniformity of the second piston pin oil supply channel 36 can be varied in ways that those skilled in the art would consider.

[0089] As shown in the figure, the second piston pin oil supply channel 36 is inclined relative to the first piston pin oil supply channel 33 and extends as described. Due to the intersection of the second piston pin oil supply channel 36 and the surface of the piston pin 30, the additional piston pin opening 37 is formed in an elliptical shape on the surface of the piston pin 30.

[0090] In the illustrated embodiment, the second piston pin oil passage is inclined at an angle of approximately 30° relative to the horizontal plane, such as... Figure 3b As shown, however, in other implementations, different tilt angles are possible.

[0091] The piston pin 30 includes annular recesses formed around its outer periphery and on either side of its longitudinal midpoint, thereby defining a first piston pin lubricant groove 38. Its purpose is described below. Clearly, when the first piston pin lubricant groove 38 is filled with oil or other liquid lubricant, it acts as a buffer reservoir for oil, thereby providing a continuous supply of pressurized oil during engine operation, including the piston pin 30.

[0092] The additional annular recess is defined to extend around the outer periphery of the piston pin 30 and serves as an additional piston pin lubricant groove 39 in use. The additional piston pin lubricant groove 39 is similar to the first piston pin lubricant groove 38, except that the additional piston pin lubricant groove 39 is wider in the length direction of the piston pin 30 to accommodate the greater length of the additional piston pin opening 37 along the length direction of the piston pin 30.

[0093] When using piston pins, the additional piston pin lubricant groove 39 also serves as a reservoir for liquid lubricant. This effect is further explained below.

[0094] Piston pin grooves 38 and 39 can be formed by machining (e.g., turning on a lathe) the outer surface of the piston pin. However, other methods of forming these features are also possible and will be apparent to those skilled in the art.

[0095] In the illustrated embodiment, the first piston pin oil groove 38 and the other piston pin oil groove 39 are formed to the same depth in the outer surface of the piston pin 30, but this is not necessarily the case. Furthermore, the grooves 38 and 39 do not necessarily have the straight cross-sectional shape shown; nor do they necessarily have to be consistent in length—in terms of size or cross-section.

[0096] Piston pin grooves 38, 39 are shown extending around the entire circumference of the piston pin, and this form is well-suited for manufacture by the aforementioned machining techniques. However, in embodiments, one or both of the piston pin grooves 38, 39 may extend only a portion of the circumferential distance, and / or one or both of the piston pin grooves 38, 39 may include a dividing platform or other features that discontinuate them.

[0097] Furthermore, in some embodiments, both slots 38 and 39 may not be necessary. In such embodiments, only a single slot 38 or 39 may be provided; while in other embodiments, slots 38 and 39 may be omitted entirely.

[0098] Furthermore, piston pin grooves 38 and 39 are not necessarily the only features formed on the surface of piston pin 30.

[0099] In the illustrated embodiment, piston pin openings 32 and 37 are longitudinally aligned with each other, but this is not necessary in other embodiments. In other words, openings 32 and 37 may not only be longitudinally spaced from each other along the length of piston pin 30, but may also be circumferentially spaced, such that openings 32 and 37 are not longitudinally aligned with each other as shown.

[0100] refer to Figure 4a , Figure 4b and Figure 4c The image shows a piston 40 according to an embodiment described herein. The piston 40 is intended for use in conjunction with the connecting rod 10 and piston pin 30 described above, although the piston 40 offers unexpected advantages even when considered independently of these components.

[0101] Piston 40 is intended for use in the cylinder of an internal combustion engine. The features of piston 40 required to achieve this purpose, which are not specifically described herein, will be apparent to those skilled in the art.

[0102] The piston 40 is formed of a heat-resistant metal alloy, and as conventionally, it can be manufactured by blank cutting and machining processes, or by a combination of casting and machining, or forging and machining operations. The piston 40 includes a generally cylindrical body 41 that defines a piston top 42 of a generally conventional design. Given the conventional nature of the piston top, the piston top 42 will not be described in detail herein.

[0103] The piston top 42 defines a cylindrical outer surface. In the illustrated embodiment, the piston top 42 includes a first compression ring recess 43 and a second compression ring recess 44 (an upper compression ring recess and a lower compression ring recess in the illustrated orientation) formed therein, adjacent to each other, for receiving the first and second compression rings in a conventional manner. Depending on the engine design with the piston 40 mounted, more or fewer compression ring recesses may be provided.

[0104] When the piston 40 is oriented as shown, a control ring groove 46 is provided in the downward direction adjacent to the second compression ring groove 44. The control ring groove 46 is also formed in the outer surface of the piston top 42 and is designed to receive the control ring in a conventional manner. In some embodiments, the control ring groove 46 may be increased by having more such grooves, or the control ring groove 46 may be absent in some other embodiments.

[0105] The piston 40 includes a corresponding first skirt portion 47 and a second skirt portion 48 that hang from the top 42.

[0106] In the illustrated embodiment, each skirt portion 47, 48 is a partially circular wall that hangs downward from the top 42. The first skirt portion 47 and the second skirt portion 48 are arranged on opposite sides of the top 42 in diameter and hang downward from the outer edge of the top 42.

[0107] Other shapes and positions of the skirt portion are possible within the scope of this disclosure. A single continuous skirt is not excluded, but it is now relatively common for pistons to have skirt portions with opposite diameters, as shown in the preferred embodiments and figures.

[0108] A hollow space 49 exists between the first skirt portion 47 and the second skirt portion 48. In the illustrated embodiment, due to the shape and position of the skirt portions 47 and 48, the space 49 is partially cylindrical as shown.

[0109] The first skirt portion 47 and the second skirt portion 48 support the spaced-apart pairs of piston pin journals or seats 51 and 52 within the space 49.

[0110] Each piston pin journal 51, 52 includes downwardly overhanging journal holes 51a, 52a ( Figure 4a The journal bores 51a and 52a can accommodate piston pins, such as the corresponding ends of the piston pin 30 described above.

[0111] In the illustrated embodiment, piston pin journals 51 and 52 are cast integrally with the rest of the piston 40 and are spaced apart in a direction orthogonal to the axis of rotation, as opposed to the skirt portions 47 and 48. On the radial inner edges of the piston pin journals 51 and 52, journals 51 and 52 are joined to corresponding first support webs 53 and second support webs 54. The first support webs 53 and second support webs 54 are spaced apart in a hollow space in the same direction as the journals 51 and 52 are spaced apart. In the illustrated embodiment, webs 53 and 54 are also cast integrally with the rest of the piston 40. However, this is not necessary in other embodiments, and the piston can be assembled from discrete components that can be fixed together, for example, by welding.

[0112] Piston 40 includes a first piston oil supply passage 56 and a second piston oil supply passage 57 with a straight, constant annular cross-section. The first piston oil supply passage 56 and the second piston oil supply passage 57 originate from internal openings 61 and 62 on opposite diametrically opposed sides of the second piston pin journal 52. Figure 4b The first piston oil supply passage 56 and the second piston oil supply passage 57 each terminate in an external opening 58, 59 on the outer surface of the corresponding first skirt portion 47 or second skirt portion 48.

[0113] Due to such Figure 4a, Figure 4b and Figure 4c As shown, the supporting web 54 extends in a plane that is offset from the lateral midpoint of each skirt portion 47, 48, so the outer openings 58, 59 are also laterally offset.

[0114] However, the arrangement of the piston oil supply channels may differ from that shown. It may include more or fewer than two channels 56, 57. These oil supply channels may pass through the portion of the piston 40 excluding the second support web 54. These oil supply channels may be non-linear and may have non-constant and / or non-annular cross-sections to achieve the desired flow and / or cooling effect.

[0115] One particular option within the scope of this disclosure is a channel arrangement that provides pressurized lubricant supply to only one side of the piston.

[0116] In this respect, in many engine designs, one side of the piston may bear the majority of the thrust generated by crankshaft action and fuel / air knock. In particular, when the piston includes different skirt portions on opposite sides of the piston as shown, it may be necessary to supply pressurized lubricant to only one skirt portion using the principles disclosed herein. This arrangement eliminates the need for channels and grooves for supplying pressurized lubricant to the other skirt portions. Those skilled in the art will readily perceive how to achieve this benefit.

[0117] Other forms of asymmetry may be included in piston designs, and these choices are within the scope of this disclosure.

[0118] Although these variations can be created, the channels 56 and 57 shown are desirable because they can be readily formed by drilling into the piston along the direction of the interior of the support web, such as the second support web 54. Therefore, channels 56 and 57 can be readily provided as modifications to existing pistons, thus allowing for upgrades based on this disclosure.

[0119] In the illustrated embodiment, each of the external openings 58, 59 leads to a corresponding recessed lubricant distribution groove 63, 64, which extends along the length of the surface of the corresponding skirt portion 47, 48. As described below, in the use of the piston, each lubricant distribution groove 63, 64 serves as a reservoir for pressurized lubricant.

[0120] The lubricant distribution grooves 63 and 64 can be readily formed, for example, by machining (e.g., milling) the surfaces of the corresponding associated skirt portions 47 and 48, or the lubricant distribution grooves 63 and 64 can be formed by other means such as casting. Machining the lubricant distribution grooves has the advantage of allowing the lubricant distribution grooves to be formed in existing pistons as an upgrade according to this disclosure.

[0121] Figure 5 This is an isometric view of a bearing insert, such as the aforementioned insert 22. It is identical to known bearing inserts for connecting rods. Figure 2a The inserts 22 and 23 shown are arc-shaped semi-annular metal parts, which are installed in pairs inside the annulus of the crankpin end 11 of the connecting rod 10. The inserts 22 and 23 serve as replaceable wear surfaces inside the annular portion 18. This means that the large end 19 and rod cap 21 of the connecting rod 10 are protected from wear due to contact with the crankpin. The bearing inserts 22 and 23 are made of a material (typically a metal alloy) selected for specific wear-resistant properties.

[0122] The bearing insert 22 differs from a typical bearing insert, and therefore differs from the illustrated insert 23 (which may be a conventional design or employ features such as those in insert 22) at least in some embodiments. In this regard, insert 22 has a central through-hole 66 formed at the midpoint of the arcuate length of insert 22; and insert 22 includes a longitudinally extending groove 67 formed as a recess in the inner surface of insert 22 during use. In the illustrated insert 22, the orifice 66 and groove 67 are laterally centered. This is not necessarily required, but in most designs of insert 22, it is contemplated that the orifice 66 and groove 67 are laterally centered. Figure 5 It is evident that the positioning of the orifice 66 and the groove 67 implies that the orifice 66 penetrates the longitudinal midpoint of the groove 67.

[0123] When inserts 22 and 23 are installed in the crank pin end 11 of connecting rod 10, orifice 66 is aligned with opening 17 of connecting rod oil supply passage 14. If necessary, retaining features may be included as part of bearing insert 22 and / or bearing insert 23 and / or large end 19 and / or rod cap 21 to ensure and maintain accurate positioning of orifice 66 as described.

[0124] As previously described, the components described so far can be supplied individually and offer technical advantages when considered in this regard. However, their practicality is greatly increased when these components are assembled together as a connecting rod, piston pin, and piston assembly, in which the dimensions and positions of various features are chosen to form a fluid flow path for pressurized lubricant extending from the large end of the connecting rod to the lubricant distribution grooves 63, 64 of the piston. This fluid flow path allows lubricant to be supplied under pressure to the skirt portions 47, 48 of the piston 40 in a manner that provides floating support to the skirt portions and thus the entire piston 40. This significantly improves vibration damping and / or lubrication and / or cooling effects compared to prior art connecting rods, piston pins, and piston assemblies.

[0125] As described herein, the components of connecting rod 10, piston pin 30, and piston 40 are as follows: Figure 6 As shown.

[0126] Figure 6 First, connecting rod 10 as described herein is shown. The crank pin end 11 of connecting rod 10 is composed of a large end 19 and a rod cap 21, which are fitted together to hold the crank pin around the crankshaft in a rotatable manner relative to the crank pin. For clarity, the crank pin is omitted from the figure, but can be readily imagined. Bearing inserts 22, 23 are arranged in a generally conventional manner between the various parts of connecting rod 10 and the crank pin.

[0127] The orifice 66 formed in the bearing insert 22 Figure 6 It is visible in the middle. As described, the orifice communicates with the connecting rod oil supply passage 14 via opening 17. The groove 67 of the bearing insert 22 is in Figure 6 It is invisible in the middle and, as mentioned earlier, is an optional feature. Based on Figure 5 It can be easily imagined.

[0128] As previously mentioned, it is readily achievable to include a pressurized lubricant supply in the crankshaft, and the lubricant exits through a channel formed inside the crankshaft via a crankpin opening formed in the surface of the crankpin. This allows the crankpin to be floated relative to the connecting rod 10 during the normal reciprocating motion of the crankshaft during engine operation. The arrangement of orifice 66, groove 67 (when present), orifice 17, and connecting rod oil supply channel 14 simultaneously provides a pressurized lubricant supply extending into the connecting rod.

[0129] The pressurized lubricant flows out of the connecting rod at the small end opening and enters the groove 28, which is located in the eyelet 26 defining the small end 12 of the connecting rod 10. As previously mentioned, the pumping of the lubricant is preferably continuous, and the groove 28 at the small end helps to achieve this, resulting in a substantially continuous supply of pressurized lubricant at the small end 12 of the connecting rod 10, even if the lubricant supply along the channel 17 is uneven for some reason.

[0130] The eyelet 26 surrounds the piston pin 30 and is rotatably held relative to the piston pin 30.

[0131] The piston pin 30 is preferably as described and shown herein, but even if not, an advantage of the connecting rod design remains. That is, even without the various piston pin features, the connecting rod is able to provide a pressurized lubricant supply to the piston pin. This allows for effective floating support of the piston pin in a manner that ensures good lubrication and cooling.

[0132] During operation of the engine equipped with connecting rods, piston pins, and piston assemblies, the orifice 26 reciprocates in a rotational manner relative to the piston pin, which can be of a fixed (relative to connecting rod 10) type or a fully pivotable type. During this relative movement of the orifice 26 and the piston pin 30, the first piston pin opening 32 travels back and forth along the groove 28 and remains open to the groove 28. Therefore, pressurized liquid lubricant is continuously pumped into the first piston pin lubricant (oil) supply passage 33, and from there into the second piston pin lubricant (oil) supply passage 36 via the connecting passage 34.

[0133] Subsequently, pressurized lubricant flows out of the piston pin through the second piston pin opening 37 and fills the additional piston pin lubricant groove 39 under pressure.

[0134] The inner openings 61 and 62 of the piston oil supply passages 56 and 57 are in fluid communication with the additional piston pin lubricant groove 39. As a result, pressurized lubricant flows along the piston oil supply passages 56 and 57 from the portion of the hollow space 49 that supports the piston pin journal 52a, and flows out through the outer openings 58 and 59. This flow of lubricant fills the lubricant distribution grooves 63 and 64 (one of the distribution grooves 63 and 64 is located in...). Figure 6 (As can be seen in the image), and thus provides floating support for the skirt portions 47, 48 of the piston 40 relative to its reciprocating cylinder.

[0135] Providing floating support in this manner reduces piston vibration within the cylinder, thereby improving engine efficiency and extending piston skirt life. Furthermore, the longitudinal reciprocating motion of the piston 10 repeatedly scrapes lubricant from the lubricant distribution grooves 63, 64 onto the outer surfaces of the skirt portions 47, 48. This lubricates the skirt portions 47, 48 more effectively than the oil splash technology of related technologies and promotes effective cooling of the skirt portions, because a large amount of lubricant is repeatedly wiped away from the bottom of the skirt portions 47, 48 as the piston 10 moves.

[0136] The oil wiped away in this way from the skirt sections 47, 48 is continuously replenished by the flow of lubricant into the lubricant distribution grooves 63, 64 via the piston oil supply passages 56, 57. The wiped-away lubricant can drip into the oil pan, which is part of the engine, under gravity, and can then be recirculated by the oil pickup and pump, which are also part of the engine.

[0137] As previously stated, although a single connecting rod, piston pin, and piston assembly are shown, this disclosure extends to various multi-cylinder versions. Those skilled in the art will understand how the components shown in the figures can be modified to be part of a multi-cylinder facility.

[0138] Furthermore, the illustrated embodiment includes a relatively simple kinematic chain comprising a crankshaft, connecting rod, piston pin, and piston as primary components. However, in some engine designs, particularly those where crankshaft motion must be transmitted over considerable distances (which may be a requirement in some stationary engines and certain ships), the kinematic chain may include additional components such as crosshead pins and crosshead bearings, which are constrained to move longitudinally within the crosshead guide. The principles of this disclosure can be readily applied to such an arrangement, such that pressurized lubricant is supplied from the crankpin supply via a channel formed in the intermediate rod, to flow under pressure through one or more openings and, as needed, one or more grooves, thereby providing floating support for the crosshead pin in the crosshead bearing.

[0139] From the crosshead bearing, pressurized lubricant can be delivered into the piston through channels formed in the piston rod. The lubricant supplied in this way can be drawn from the piston interior under pressure via a similar pathway... Figure 4b The channels and optional grooves visible in features 56, 58, 57, and 59 flow to its skirt to provide a pressurized lubricant supply to the piston outside its cylinder bore. Therefore, the principles of the invention can be readily extended to multi-component connections between the crankshaft and piston, while continuing to provide the benefits of floating support for the piston and, if necessary, the crosshead pin.

[0140] As mentioned above, Figure 6The operation method of the components, as well as the parts forming part of the components and the components themselves, has significant advantages, as illustrated. Furthermore, each of the components of the component can be manufactured as a new part or by modifying existing engine parts. This disclosure extends to methods of manufacturing the components. In the preferred, but not limiting, embodiments described, the manufacturing steps can conveniently be simple steps, such as drilling, milling, and lathe turning of metal parts, as will be apparent to those skilled in the art. However, as also illustrated, within the scope of this disclosure, there can be various variations in the design and manufacturing methods of the parts.

[0141] Although the various grooves 28, 38, 39, 63, and 64 are shown as annular arcs extending in the circumferential direction, this is not necessarily the case. Different groove paths can be employed on the surface forming the grooves, for example, to achieve specific flow effects in the lubricant. As a non-limiting example in this regard, one or more grooves can be formed in a sinusoidal pattern.

[0142] Furthermore, the cross-section of the groove need not be uniform, nor does it need to adopt the regular polygonal shape shown. In general, the groove can take various forms that those skilled in the art can conceive of; and all such variations are included within the scope of this disclosure.

[0143] Unless the context otherwise indicates, the preferred and selected aspects, features, or parameters of the present invention should be regarded as disclosed in any and all preferred and selected combinations with all other aspects, features, and parameters of the present invention.

[0144] Any obviously prior disclosure of documents listed or discussed in this specification should not necessarily be regarded as an admission that such documents are part of the relevant art or common general knowledge.

Claims

1. A piston pin for an internal combustion engine, the piston pin being a rigid and elongated cylindrical member having formed therein: at least one first piston pin oil supply channel extending from a first piston pin opening located on an outer surface of the cylindrical member to an end adjacent to a diameter center of the piston pin; and a second piston pin oil supply channel extending from the end of the first piston pin oil supply channel toward a further piston pin opening located on the outer surface of the cylindrical member, the further piston pin opening being spaced apart from the first piston pin opening along the length of the cylindrical member, the first piston pin oil supply channel and the second piston pin oil supply channel being in fluid communication with each other at or near the end to allow fluid to flow from the first piston pin opening along the first piston pin oil supply channel to the end, and then along the second piston pin oil supply channel to the further piston pin opening.

2. The piston pin according to claim 1, wherein, The first piston pin opening is located approximately halfway along the length of the outer surface of the cylindrical member.

3. The piston pin according to claim 1 or claim 2, wherein the piston pin includes an elongated hole formed therein, the elongated hole being coaxial with the elongated cylindrical member and extending from one end of the cylindrical member to the other end.

4. The piston pin according to claim 3, wherein, The material of the cylindrical component fluidly isolates the elongated orifice from the first piston pin oil supply channel and the second piston pin oil supply channel.

5. The piston pin according to any one of claims 1 to 4, the piston pin comprising a first piston pin groove formed as a recess in the surface of the piston pin near the first piston pin opening.

6. The piston pin according to any one of claims 1 to 5, wherein the piston pin includes an additional piston pin groove formed as a recess in the surface of the additional piston pin near the additional piston pin opening.

7. A piston for use in a cylinder of an internal combustion engine, the piston comprising a cylindrical body defining a piston top and at least one first skirt portion that hangs from the piston top in use, one or more of the skirt portions defining a hollow space and supporting at least one piston pin journal in the space, the piston pin journal for receiving a piston pin in the piston pin journal, the piston including at least one first piston oil supply passage formed in the piston for supplying pressurized oil from the hollow space to the first skirt portion, the hollow space including an internal opening of the piston oil supply passage, and the piston oil supply passage terminating at or near an external opening located on or near the outer surface of the first skirt portion.

8. The piston of claim 7, wherein the piston comprises a pair of spaced-apart piston pins supported in the space.

9. The piston of claim 7 or claim 8, wherein the piston includes a recessed lubricant distribution groove formed in the outer surface of the first skirt portion and extending around a portion of the periphery of the first skirt portion, wherein, The outer opening leads to the recessed groove.

10. The piston according to any one of claims 7 to 9, further comprising a second skirt portion hanging from the top of the piston on the side opposite to the first skirt portion, the piston comprising a first piston oil supply passage and a second piston oil supply passage extending on opposite sides of the transverse centerline of the piston, the piston further comprising corresponding paired internal openings located in the hollow interior and communicating with the piston oil supply passages; the first piston oil supply passage terminating at a first external opening located at or near the outer surface of the first skirt portion; and the second piston oil supply passage terminating at a second external opening located at or near the outer surface of the second skirt portion.

11. The piston of claim 10, wherein the piston includes a pair of recessed oil distribution grooves, the pair of recessed oil distribution grooves being formed in the outer surfaces of the first skirt portion and the second skirt portion respectively and extending around a portion of the periphery of the respective skirt portion, wherein, The corresponding external opening of the piston oil supply passage leads to one of the paired recessed oil distribution grooves.

12. The piston according to any one of claims 7 to 11, the piston comprising at least one web, the at least one web being rigidly fixed in the internal space and supporting at least one piston pin journal, wherein, At least one of the piston oil supply passages is formed in the at least one web and extends along the at least one web.

13. An assembly of a connecting rod, a piston pin, and a piston, said assembly comprising: A connecting rod having a crank pin end, a small end, and a longitudinally extending rod rigidly interconnecting the crank pin end and the small end, the rod having an internal connecting rod oil supply passage along its length, the connecting rod oil supply passage including a crank pin end opening and a small end opening respectively located at the crank pin end and the small end, thereby allowing oil supplied to the connecting rod oil supply passage under pressure at the crank pin end to flow out at the small end under pressure; the connecting rod receiving a piston pin according to any one of claims 1 to 6 in an orifice defined at the small end of the connecting rod, a portion of the piston pin being received in at least one piston pin journal of a piston according to any one of claims 7 to 11, the orifice being rotatable relative to the piston pin and the piston pin being rotatable relative to the piston pin. The plug pin is constrained relative to the orifice, and the small end opening of the connecting rod oil supply passage is open in a position where, as the orifice rotates relative to the piston pin, the small end opening is at least periodically aligned to fluid communication with the first opening of the piston pin, and the other piston pin opening is at least periodically aligned to fluid communication with the inner opening of the hollow interior of the skirt. Thus, when pressurized oil is supplied via the crankpin end opening of the connecting rod oil supply passage, the oil is conveyed under pressure along the connecting rod oil supply passage, along the first piston pin oil supply passage, along the second piston pin oil supply passage, and at least one of the piston oil supply passages, to flow out under pressure through at least one of the outer openings, thereby supporting, and / or damping, and / or lubricating, and / or cooling the skirt of the piston.

14. The assembly of connecting rod, piston pin, and piston according to claim 13, wherein, The piston pin is fixed relative to the small end of the connecting rod and the piston.

15. The assembly of connecting rod, piston pin, and piston according to claim 13, wherein, The piston pin is pivotable relative to the connecting rod and the piston.

16. The assembly of connecting rod, piston pin, and piston according to any one of claims 13 to 15, the assembly further comprising a crankshaft crank pin rotatably constrained relative to the large end and rod cap of the connecting rod, the crank pin being operatively connected to a supply of pressurized oil via one or more internal channels formed in the crank pin, the internal channels terminating in one or more crank pin oil orifices, the crank pin oil orifices being in fluid communication at least from time to time with the crank pin end opening of the connecting rod oil supply passage during use of the assembly, thereby supplying oil under pressure into and along the connecting rod oil supply passage.

17. The assembly of connecting rod, piston pin, and piston according to any one of claims 13 to 16, wherein, The crankpin end of the connecting rod includes: a large end, which is integrally formed with the rod or is fixed to the rod; and a rod cap, which is fixed to the large end, the large end defining a first arcuate inner surface and the rod cap defining a second arcuate inner surface, the first arcuate inner surface and the second arcuate inner surface being abutted at both ends to define an annular surface intended to surround the crankpin and movably hold the crankpin when the rod cap is fixed to the large end and the crankpin is located between the respective arcuate inner surfaces.

18. The assembly of connecting rod, piston pin, and piston according to claim 17, wherein, The connecting rod includes one or more bearing inserts that are held inside the annular surface during use to support a crank pin that is movably held by the rod cap and the large end; and wherein at least one of the bearing inserts includes an orifice extending through the bearing insert at a location aligned during use with the crank pin end opening of the connecting rod oil supply passage.

19. A method for cooling, and / or lubricating, and / or stabilizing the skirt of a piston in an internal combustion engine, the method comprising: Oil is allowed to flow under pressure through the crank pin end opening of the connecting rod of the assembly according to any one of claims 15 to 17 along the connecting rod oil supply passage to the first opening of the piston pin according to any one of claims 1 to 6; and then exits through the first piston pin oil supply passage and the second piston pin oil supply passage by means of the additional opening to reach the inner opening of the piston according to any one of claims 7 to 11. And then, under pressure, the oil flows through the outer opening along the piston supply passage to the outer surface of the skirt, thereby providing floating support for at least the skirt, and / or damping the vibration of at least the skirt, and / or lubricating and / or cooling at least the skirt.

20. A method for manufacturing a piston according to claim 7 or claim 8, the method comprising the following steps: At least one first piston oil supply passage is formed in the piston to interconnect the hollow space with the first skirt portion, such that: the hollow space includes an inner opening of the piston oil supply passage and an outer opening of the piston oil supply passage located at or near the outer surface of the first skirt portion.

21. The method of manufacturing a piston according to claim 20, the method comprising the steps of claim 20 and the additional steps of forming a recessed lubricant distribution groove in the outer surface of the first skirt portion and extending the recessed lubricant distribution groove around at least a portion of the periphery of the first skirt portion such that the outer opening leads to the recessed groove.

22. The method according to claim 20 or claim 21, wherein, The piston includes at least one web, which is rigidly fixed in the internal space and supports at least one piston pin journal, and wherein the method includes: forming at least one first piston oil supply channel in the material of the at least one web and extending the first piston oil supply channel along the material of the at least one web.

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