COMBUSTION ENGINE

BACKGROUND

[0001] The present invention relates generally to the field of internal combustion engines, and particularly to the field of oil filters for internal combustion engines.

SUMMARY

[0002] One embodiment of the invention relates to an internal combustion engine. The engine includes an engine block including a cylinder and a cylinder head. The cylinder head includes an intake valve and an exhaust valve, a piston positioned within the cylinder and configured to reciprocate within the cylinder, a crankshaft driven by the piston and configured to rotate about a crankshaft axis, a camshaft driven by the crankshaft via a timing gear, and a cam gear coupled to the camshaft. The cam gear includes an oil filter ring attached to the cam gear and a filter groove formed by the cam gear and the oil filter ring, wherein the filter groove is configured to collect debris from oil as oil moves into the filter groove due to centrifugal forces from the rotation of the cam gear.

[0003] Another embodiment of the invention relates to an oil filter assembly for use with an engine. The oil filter assembly includes a cam gear configured to be coupled to a camshaft rotatable about a camshaft axis. The cam gear includes a central bore configured to couple to the camshaft, a top face, a first annular wall, and a second annular wall, wherein the first annular wall is nearer the camshaft axis relative to the second annular wall, wherein the first annular wall and the second annular wall are substantially perpendicular the top face. An annular channel is formed on the top face proximate the first annular wall. The oil filter assembly additionally includes an oil filter ring attached to the cam gear at the second annular wall, wherein a gap is formed between the oil filter ring and the annular channel of the cam gear, the gap configured to collect debris from oil as oil moves into the gap due to centrifugal forces from the rotation of the cam gear.

[0004] Alternative exemplary embodiments relate to other features and combinations of features as may be generally recited in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures.

[0006] FIG. 1 is a perspective view of an internal combustion engine, according to an exemplary embodiment.

[0007] FIG. 2 is a perspective view from below of the engine of FIG. 1, according to an exemplary embodiment.

[0008] FIG. 3 is a schematic view of a portion of the engine of FIG. 1, according to an exemplary embodiment.

[0009] FIG. 4 is a perspective view of a camshaft of the engine of FIG. 1, according to an exemplary embodiment.

[0010] FIG. 5 is a section view of the camshaft of FIG. 4, according to an exemplary embodiment.

[0011] FIG. 6 is a section view of the oil filter of the camshaft of FIG. 4, according to an exemplary embodiment.

[0012] FIG. 7 is a perspective view of the camshaft of FIG. 4 with the oil filter removed, according to an exemplary embodiment.

DETAILED DESCRIPTION

[0013] Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting.

[0014] Typical oil filters require routine maintenance and replacement due to clogging in the filter throughout the life of the engine. Furthermore, if a typical oil filter is clogged or plugged up by debris (e.g., suspended solids, dirt, metal particles, carbon), unfiltered oil may enter the engine through a by-pass valve in the filter and may cause damage to the engine. Thus, providing an oil filtering system that does not require maintenance during the life of the engine is desirable. Furthermore, decreasing the possibility of premature engine wear due to prolonged exposure to unfiltered oil can improve the function of the engine over the engine lifetime.

[0015] The oil filter assembly, as described below, may be used to replace a typical oil filter (e.g., filter with pleated paper to filter oil drawn from the oil reservoir). When the typical oil filter clogs up, unfiltered oil passes through a bypass valve on the filter to be routed once again through the lubrication passages in the engine. Thus, failure to replace conventional oil filters according to recommended maintenance procedures (e.g., approximately every 100 hours) can result in premature engine wear, poor engine performance, and/or engine failure. Eliminating or substantially reducing the need for maintenance on an engine using a permanent or semi-permanent oil filter assembly can alleviate concerns regarding engine performance and/or failure.

[0016] Frequently, engine manufacturers recommend changing a conventional oil filter every 100 hours of engine operation for a two-cylinder engine. For an engine with an expected engine life of 500 hours, the engine would require at least 5 oil filter changes. The oil filter assembly described herein provides filtration for greater than 600 hours of engine life. Thus, for an engine with an expected engine life of 500 hours the oil filter assembly would last the entire life of the engine. Requiring no oil filter changes reduces the necessary maintenance for the engine.

[0017] Referring to FIGS. 1-2, an internal combustion engine 100 is shown according to an exemplary embodiment. The internal combustion engine 100 includes an engine block 105 having two cylinders 110 and 112, two cylinder heads 125 and 127, two pistons, and a crankshaft 104. Each piston reciprocates in a cylinder along a cylinder axis to drive the crankshaft 104. The crankshaft 104 rotates about a crankshaft axis 107. The crankshaft 104 is positioned in part within a sump or crankcase cover 116. The engine 100 also includes a fuel system for supplying an air-fuel mixture to the cylinder (e.g., a carburetor, an electronic fuel injection system, a fuel direct injection system, etc.), a camshaft 130 for actuating intake and exhaust valves in the cylinder heads, a muffler, a flywheel, and a blower fan. The engine 100 includes a blower housing 117 configured to direct cooling air over the engine block 105 and other components of the engine. The blower fan pulls air into the blower housing 117 through an air inlet 111. The cylinder and cylinder axis may be oriented horizontally (i.e., a horizontal cylinder engine), vertically (i.e., a vertical cylinder engine), or at an angle (i.e., a slanted engine). The engine may include one cylinder or two or more cylinders. The internal combustion engine 100 may be used in outdoor power equipment, standby generators, portable jobsite equipment, or other appropriate uses.

Outdoor power equipment includes lawn mowers, riding tractors, snow throwers, pressure washers, portable generators, tillers, log splitters, zero-turn radius mowers, walk-behind mowers, riding mowers, industrial vehicles such as forklifts, utility vehicles, etc. Outdoor power equipment may, for example, use an internal combustion engine to drive an implement, such as a rotary blade of a lawn mower, a pump of a pressure washer, the auger a snow thrower, the alternator of a generator, and/or a drivetrain of the outdoor power equipment. Portable jobsite equipment includes portable light towers, mobile industrial heaters, and portable light stands.

[0018] As shown in FIG. 2, an oil filter assembly 103 is included with the engine 100. The oil filter assembly 103 filters debris from the oil used to lubricate the engine 100. The oil filter assembly 103 includes an oil filter housing 109, a cover or cap 113, and a filter housed within the oil filter housing 109. In some embodiments, the oil filter assembly 103 is used in conjunction with the oil filter assembly 102 described below. In other embodiments, the engine 100 does not include the oil filter assembly 103 and instead, only the oil filter assembly 102 described below is included with the engine 100 and the oil filter assembly 102 performs all of the oil filter of the oil used to lubricate the engine 100.

[0019] Referring to FIG. 3, an internal combustion engine 100 including an oil filter system 102 is shown according to an exemplary embodiment. The engine 100 is shown to include an engine block 105 having a cylinder 110, a piston 115, a cylinder head 125, a camshaft 130, and a crankshaft. The piston 115 reciprocates in the cylinder 110 to drive the crankshaft. The crankshaft rotates about a crankshaft axis. As illustrated in FIG. 3, the engine 100 includes two cylinders arranged in a V-twin configuration. In other

embodiments, the engine includes a single cylinder. In other embodiments, the engine includes two or more cylinders that can be arranged in different configurations (e.g., inline, horizontally opposed, etc.).

[0020] The piston 115 is coupled to a crankshaft with a connecting rod 135 to convert translation of the piston 115 to rotation of the crankshaft. The engine 100 includes a camshaft 130 driven by a geared connection between a cam gear 145 and a timing gear coupled to the crankshaft. The camshaft 130 rotates about a camshaft axis 120 (shown in FIG. 4). The camshaft 130 includes cams 150 to engage tappets 155 as the camshaft 130 rotates. The cams 150 rotate with the rotation of the camshaft 130 such that tappets 155 move between relatively nearer and further distances from the camshaft axis 120 during the combustion processes. The tappets 155 drive push rods 160 to rotate rocker arms 195 to, in turn, operate intake and exhaust valves that direct fuel and air flow through the combustion chamber, where combustion processes interact with the piston 115. The cylinder 110 includes an intake port 165 in which the intake valve 170 is positioned and an exhaust port 175 in which the exhaust valve 180 is positioned. A valve seat 185, 190 is press fit to the cylinder 110 around an aperture (e.g., opening) to each of the intake port 165 and the exhaust port 175.

[0021] Referring to FIGS. 4-5, the cam gear 145 with the oil filter system 102 is shown according to an exemplary embodiment. An outermost wall 152 of the cam gear 145 includes gear teeth to engage with the crank gear of the engine 100. The cam gear 145 includes a central bore 132 configured to couple the cam gear 145 to the camshaft 130. The cam gear 145 further includes a top face 143. The top face 143 is shown to be circular in shape. The top face 143 is defined by an annular transition surface 146 around the circumference of the top face 143. The top face 143 is shown to include an oil drain 147 (e.g., aperture or opening formed through the cam gear 145). The oil drain 147 is configured to allow free flow of oil through the top face 143 of the cam gear 145 so that excessive amounts of oil do not accumulate on the top face 143.

[0022] The cam gear 145 further includes a first annular wall 148 and a second annular wall 142 with a lip 141 (e.g., tab, protrusion) formed between the first annular wall 148 and the second annular wall 142. As shown in FIG. 5, the first annular wall 148 is positioned nearer the central bore 132 of the cam shaft 145 than the second annular wall 142 and is smaller in diameter.

[0023] The cam gear 145 additionally includes an annular channel 149 formed between the first annular wall 148 and the annular transition surface 146. The first annular wall 148 extends up from and substantially perpendicular to the annular channel 149. The first annular wall 148 extends between the annular channel 149 and the lip 141. The second annular wall 142 extends up from the lip 141 and substantially parallel to the first annular wall 148. The annular channel 149 is formed at a depth 154 below the top face 143. The annular transition surface 146 is configured to allow oil residue and other particles to move into and collect within the annular channel 149 during engine operation.

[0024] The oil filter system 102 includes an oil filter ring 200 and a filter groove 144. In some embodiments, the oil filter system 102 additionally includes one or more ribs 240, discussed further herein. The oil filter system 102 is configured to provide oil filtration to the engine 100 during operation.

[0025] As shown in FIGS. 4-6, an oil filter ring 200 is included on the cam gear 145. The oil filter ring 200, in combination with the filter groove 144, and in some cases, the ribs 240, filters debris (e.g., oil residue, dirt, metal particles, carbon, other foreign matter) through centrifugal filtration. As the camshaft 130 rotates about the camshaft axis 120, the cam gear 145 rotates and generates a centrifugal force extending outward from the camshaft axis 120. Oil debris is forced radially outward on the top face 143 of the cam gear 145 and into the filter groove 144, described further herein.

[0026] As shown in FIG. 6, the oil filter ring 200 includes a top surface 210, a bottom surface 205, an outside annular wall 215, and an inside annular wall 220. The oil filter ring 200 is also shown to include an annular groove 225 with angled surfaces 230. The annular groove 225 is included in the top surface 210 of the oil filter ring 200. The oil filter ring 200 is coupled to the cam gear 145 at the second annular wall 142. According to an exemplary embodiment, the oil filter ring 200 is ultrasonically welded to the cam gear 145. In other embodiments, the oil filter ring 200 is otherwise coupled to the cam gear 145 (e.g., with fasteners, with a threaded engagement, adhesively secured, welded, etc.). In some embodiments, the oil filter ring 200 is additionally coupled to the lip 141. In other embodiments, the oil filter ring 200 is coupled to other portions of the cam gear 145. The oil filter ring 200 is made of a plastic material. In other embodiments, the oil filter ring 200 can be made from other suitable materials. The cam gear 145 is made from a plastic material. In other embodiments, the cam gear 145 can be made from other suitable materials.

[0027] Shown in FIG. 5, a filter groove 144 is formed between the oil filter ring 200 and the annular channel 149 of the cam gear 145 to collect the oil residue and debris that is forced outward on the cam gear 145. The filter groove 144 is formed in the gap 156 defined by the annular channel 149 of the cam gear 145 and the bottom surface 205 of the oil filter ring 200. The filter groove 144 is defined on a third side by the first annular wall 148 of the cam gear 145. Oil residue and debris is filtered by entering the filter groove 144. In operation, relatively larger particles and debris will be forced further outward on the cam gear and further into the filter groove 144 against the first annular wall 148 than relatively smaller particles and debris.

[0028] Filtered oil residue and other debris are trapped between the annular channel 149 and the oil filter ring 200 within the filter groove 144. As the cam gear 145 rotates, the oil residue and other debris move outward away from the cam shaft axis 120 on the top face 143 of the cam gear 145, move down the annular transition surface 146, and into the annular channel 149. The annular channel 149 is positioned at a depth 154 below the top face 143 so as to limit the amount of oil residue and other debris that can exit the filter groove 144. Additionally, the bottom surface 205 of the oil filter ring 200 is configured to further limit the amount of oil residue and other debris that can exit the filter groove 144, while still allowing oil to exit the filter groove 144.

[0029] Referring to FIG. 7, the cam gear 145 is shown to include one or more ribs 240 (e.g., angled walls, protrusions, surfaces, barriers). The ribs 240 are configured to facilitate the filtering of oil using the oil filter system 102. As such, the ribs 240 are configured to catch and trap oil residue and debris, while allowing oil to flow past. The ribs 240 extend inward on the cam gear 145 from a base 237. The base 237 is shown to be circular in shape. In other embodiments, the base 237 can have any other suitable shape. The ribs 240 are made from a plastic material. In other embodiments, the ribs 240 can be made of any other suitable material. The base 237 is positioned within the filter groove 144 and under the oil filter ring 200. The base 237 is coupled to the first annular wall 148 of the cam gear 145. In one embodiment, the base 237 is ultrasonically welded to the cam gear 145 at the first annular wall 148. In another embodiment, the base 237 is otherwise coupled to the cam gear 145 (e.g., with fasteners, with a threaded engagement, adhesively secured, welded, etc.). In other embodiments, the base 237 is not a separate piece and is instead formed as part of the cam gear 145. [0030] The ribs 240 extend upward substantially perpendicular from the annular channel 149 of the filter groove 144. The ribs 240 extend inward on the cam gear 145 from the first annular wall 148 toward the camshaft axis 120. In one embodiment, the ribs 240 contact the annular channel 149. In other embodiments, the ribs 240 do not contact the annular channel 149. In some embodiments, the ribs 240 contact the bottom surface 205 of the oil ring filter 200. In other embodiments, the ribs 240 do not contact the bottom surface 205.

[0031] The ribs 240 each form a collection pocket 245 (e.g., gap, space, corner) into which the oil residue and other debris is directed by the centrifugal force of the rotation of the cam shaft 130. As illustrated in FIG. 7, the collection pocket 245 is rounded in shape. The collection pocket 245 can be any other shape suitable to collect the oil residue and debris.

[0032] The ribs 240 are positioned at an angle 250 relative to the base 237. According to an exemplary embodiment, the angle 250 is less than 90 degrees. According to an exemplary embodiment, the ribs 240 are positioned angularly such that the direction of rotation of the cam gear 145 facilitates the entry of oil residue and other debris into the collection pocket 245 of each rib 240. For example, as shown in FIG. 7, the direction of rotation of the cam gear 145 is in a counter-clockwise direction, while the ribs 240 are similarly angled toward that direction.

[0033] Oil is collected inside an oil sump or reservoir formed by the engine block 105 and the crankcase cover for distribution within the engine 100 to lubricate moving components, including the piston 115, the crankshaft, the camshaft 130, and the cam gear 145. Oil lubricates these and other various components of the engine via oil passageways leading to bearing surfaces throughout the engine. As oil is used for lubrication during the life of the engine 100, dirt, metal particles, carbon, and other foreign matter and debris is removed from the oil for proper engine function. The oil filter assembly 102 filters debris using the rotational nature of the cam gear 145 to force unwanted debris into the filter groove 144. The debris is trapped in the filter groove 144 by the centrifugal force of the cam gear 145 such that all or substantial amount of the unwanted debris cannot escape the filter groove 144 during the engine lifetime. Beneficially, the oil filter assembly 102, including the oil filter ring 200, filter groove 144, and ribs 240, can last the expected life of the engine such the oil filter assembly 102 does not need to be maintained (e.g., replaced, cleaned) during the course of the engine lifetime. For a two-cylinder engine, the expected engine life may be up to approximately 500 hours of runtime. The oil filter assembly 102 can endure greater than 600 hours of engine performance time without any maintenance or replacement required. As such, the oil filter assembly 102 can last longer than the expected engine life of a two-cylinder engine without maintenance or replacement.

[0034] The construction and arrangement of the apparatus, systems and methods as shown in the various exemplary embodiments are illustrative only. Although only a few

embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, some elements shown as integrally formed may be constructed from multiple parts or elements, the position of elements may be reversed or otherwise varied and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present disclosure.

[0035] Although the figures may show or the description may provide a specific order of method steps, the order of the steps may differ from what is depicted. Also two or more steps may be performed concurrently or with partial concurrence. Such variation will depend on various factors, including software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule based logic and other logic to accomplish the various connection steps, processing steps, comparison steps and decision steps.