DESC:FIELD OF THE INVENTION
[0001] The subject matter as described herein, relates generally to an internal combustion engine and more particularly, but not exclusively, to an oil filtering device preferably usable with an internal combustion engine.

BACKGROUND OF THE INVENTION
[0002] A conventional two wheeled vehicle is powered by an internal combustion engine generally disposed at a lower half of the vehicle. This engine converts chemical energy into mechanical energy by combustion of air-fuel mixture within a combustion chamber of the engine. The said engine, among other components, has a cylinder comprising a cylinder head atop or in front of the cylinder and is receiving a reciprocating piston from the bottom or the rear. On combustion of the air-fuel mixture, the piston transfers the energy generated during combustion to a crankshaft through a connecting rod thereby driving the crankshaft. In this way, the reciprocatory motion of the piston is converted to rotatory motion of the crankshaft. The crankshaft is housed inside a crankcase beneath or behind the cylinder block. In order to set the vehicle into motion, the power supplied to the crankshaft of the internal combustion engine is carried to a wheel of the vehicle, in a controllable way, through a transmission system. The transmission system in the conventional vehicle employs a clutch and a gearbox with plurality of gears, wherein gear shift is achieved manually which enables gears to be selected only in an ascending or descending sequence. A gear less transmission system, called a continuously variable transmission system, is also known where the gearshift is achieved by centrifugal forces.
[0003] Conventionally, the internal combustion engine is provided with a lubrication system to lubricate various internal engine components when the engine is operated continuously. An oil pump is utilized to draw and deliver the lubrication oil to desired locations within the engine for lubrication and cooling purposes under low, medium or high engine speed conditions. The lubrication oil circulates through a lubrication channel, which involves transmission of oil through a particular channel for achieving the desired lubrication and cooling of the engine components. The lubrication oil functions as a lubricating agent and a cooling agent in an internal combustion engine. The oil used for this purpose may be stored in an oil sump, which also acts as a repository for the oil expelled from the engine components as a result of their working.
[0004] When needed, the oil is drained out from the lowest portion of the oil sump by removing a drain bolt. The provision of oil drain in the lowest portion of the oil sump affects the ground clearance of the engine. Further, the oil sump is also provided with an oil filter which is separately placed into the oil sump during assembly. The oil filter filters the lubrication oil before it enters the lubrication channel of the engine. During the servicing of the engine, it is probable that the mechanic forgets to insert the oil filterinto the oil sump and closes the crankcase from the bottom by the drain bolt which affects the engine life. This also has an affect on the serviceability of the oil filter because other associated components needs to be removed first to access oil filter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description and accompanying drawings where:
[0006] FIG. 1 is a perspective view of a power unit (IC engine) in a motorcycle according to the present invention.
[0007] FIG. 2 is a selective exploded view of a cylinder assembly and a crankcase assembly of the power unit of FIG. 1.
[0008] FIG. 3 shows a front sectional view of the crankcase assembly illustrating an oil sump.
[0009] FIG. 4 (a) shows a perspective view of the oil filtering device according to an embodiment of the present invention.
[00010] FIG. 4 (b) shows a sectional view of FIG. 4(a).
[00011] FIG. 5 shows a sectional side view of the engine with an oil filtering device installed in the oil sump.
BRIEF DESCRIPTION OF THE INVENTION
[00012] The present invention is aimed at overcoming the challenges associated with the oil sump of a conventional internal combustion engine and provides a standalone oil filtering device. It is an object of the present invention to provide a compact oil filtering device which enables better ground clearance for the engine. It is also an object of the present inventiom to provide an oil filtering device leading to a reduction in number of parts required for assembly thus facilitating easy assembly and easy serviceability. It is another object of the present invention to simplify the design of the oil filtering device for easy and quick assembly and achieve a reduction in its weight and cost.
[00013] The present subject matter and its embodiments would now be described in greater detail in conjunction with the figures in the following description. The following description provides a convenient illustration for implementing exemplary embodiments of the invention. It is to be noted that terms “front”, “rear”, “left”, “right”, and like terms are used herein based on the direction indicated in the drawings. Incidentally, in the drawings to be used in the following explanation including FIG. 1, the front of the engine is indicated by an arrow “Fr” and the rear of the engine is indicated by an arrow “Rr”, and further the lateral right side of the engine is indicated by an arrow “R” and the lateral left side of the “engine” is indicated by an arrow “L” as necessary. Furthermore, a longitudinal axis refers to a front to rear axis relative to the engine, while a lateral axis refers to a side to side, or left to right axis relative to the engine. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The internal combustion engine shown in ensuing drawings is a four stroke single cylinder internal combustion engine with a forwardly titled cylinder head generally mounted on a scooter type motorcycle. However, the concepts disclosed in the present invention can be practiced in other engines like a vertical engine.
[00014] FIG. 1 shows a perspective view of an internal combustion engine 100 according to an embodiment of the present invention. The engine 100 is one made by unitizing a cylinder assembly 12 and a crankcase assembly 14, and is rotatably supported on a rear wheel of the motorcycle. The rear portion of the crankcase assembly 14 includes a power transmission system. In an embodiment of the engine, the power transmission system includes a continuously variable transmission made by using a belt and a pulley. The engine 100 has an air cleaner 22 mounted on the upper surface side of the crankcase assembly 14 and positioned towards the rear portion of the engine when seen in a side view. The air cleaner 22 exhibits a box shape generally, and has an air intake pipe extending from the vicinity of an upper portion thereof. It also comprises of an intake hose 24 extending from a right side portion (when seen in a top view) towards a carburettor, which further carries an air-fuel mixture for combustion through an intake pipe 26. Further, the crankcase assembly 14 is covered from a left side by a variator cover 18, which seals the crankcase assembly from the left side L and supports the components of the continuously variable transmission.
[00015] FIG. 2 shows a selective exploded view of the engine 100 illustrating the various engine components in detail. The cylinder assembly 12 is made in a manner that a cylinder head cover 12A, a cylinder head 12B and a cylinder 12C are sequentially joined in a front to rear direction. For a vertical engine, they would be joined in a top to bottom direction. The cylinder head 12B comprises of a valve train assembly and is covered by the cylinder head cover 12A. The cylinder 12C receives a reciprocating piston (not shown) from the rear and generates the mechanical energy to drive the engine. The cylinder assembly 12 is disposed in a manner that the cylinder axis falls along the longitudinal axis of the engine 100. Further, the intake pipe 26 communicates with an intake port in the cylinder head 12B, and through an intake passage constituted by these members, the purified air is supplied to the intake port in the cylinder head 12B from the air cleaner 22. In the lower surface side of the cylinder assembly 12, an exhaust port is formed, and from the exhaust port, an exhaust pipe extends rearward while bending and is connected to a muffler at the rear of the motorcycle.
[00016] A head sealing member 13 is disposed between a rear surface of the cylinder head 12B and a front surface of the cylinder 12C. A second sealing member called as a block sealing member 15 is disposed between a rear surface of the cylinder 12C and the front surface of the crankcase assembly 14. The front surface is referred to as crankcase block seating surface (CBSF) 28 because the rear surface of the cylinder rests on the crankcase through CBSF 28. In the present embodiment, the CBSF 28 faces the front direction of the engine 100. The head sealing member 13 and the block sealing member15 seal the respective mating surfaces against any oil or pressure leaks.
[00017] The crankcase assembly 14 is disposed rearwardly of the cylinder assembly and comprises of a left casing 40 and a right casing 30 joined to each other to develop into the crankcase assembly 14. The left casing 40 is disposed toward the left side L of the crankcase assembly and the right casing 30 is disposed toward the right side R of the crankcase assembly. The left casing 40 is joined to the right casing 30 at a mating face 33. In an embodiment, a sealing member is provided between the left casing 40 and the right casing 30 to seal the two. A crankshaft 56 is supported by the left casing 40 and the right casing 30 in the engine width direction from the left L to the right R direction. In an embodiment, the left casing 40 comprises of a left crankshaft opening 41a as shown in FIG. 2. A left bearing is supported in the left crankshaft opening 41a. Similarly, the right casing 30 comprises of a right crankshaft opening 31a. A right bearing is supported in the right crankshaft opening 31a. The left crankshaft opening 41a is co-axial to the right crankshaft opening 31a.
[00018] FIG. 3 shows a sectional view of a front portion of the crankcase assembly 14. The crankshaft 56 is rotatably supported in the left crankshaft opening 41a and the right crankshaft opening 31a respectively in a manner that the long axis of the crankshaft 56 (referred in the description by 56L-56R) is parallel to the lateral axis L-R of the engine and perpendicular to the longitudinal axis Fr-Rr of the engine. The rotation of the crankshaft 56 drives the valve train assembly in the cylinder head 12B through a cam chain. An oil sump 51 is formed in a lower portion within the crankcase assembly. The oil sump 51 is jointly formed by the left casing 40 and the right casing 30. The oil sump 51 is spread from the left casing to the right casing and is positioned lower than all other engine components. The lubrication oil is carried from the oil sump 51 to the right casing 30 of the crankcase assembly 14 through the left casing 40. An oil pump 58 receiving drive from the crankshaft 56 pumps the lubrication oil from the oil sump 51 into a lubrication channel. The lubrication channel for transfering the lubrication oil from the left casing 40 to the right casing 30 involves a series of drill holes and oil openings to route the oil toward the crankshaft 56 and the cylinder head 12B.
[00019] As shown in FIG. 2 and FIG. 3, the oil sump is provided with an oil filtering device 60 at a lower front portion of a right face of the left casing 40. The oil filtering device 60 closes the oil sump from the bottom and seals the crankcase assembly. An oil chamber 46 is provided in the left casing 40 where the oil filtering device 60 is disposed. The oil chamber 46 is sealed towards a left face of the left casing 40 by an oil pump cover 50. The oil pump cover 50 includes an oil seal to seal the crankshaft 56 from the left direction. It also keeps the dry power transmission system disposed at a rear portion of the left casing 40 away from the lubrication oil. An oil pump sealing member 48 is disposed between a mating surface of oil chamber 46 and the oil pump cover 50. It further seals the oil chamber 46 from any undesirable oil or pressure leaks. The left casing 40 is covered from the left side by the variator cover 18 as shown in FIG. 1.
[00020] The oil filtering device 60 is now described in detail with the help of FIG. 4 (a) and FIG. 4 (b). The oil filtering device 60 comprises of lower portion 61, a middle portion 62 and an upper portion 63. The lower portion 61, the middle portion 62 and the upper portion 63 are integrally formed. Hence, the oil filtering device 60 is an individual standalone device. The lower portion 61 comprises of a means to secure the device to the crankcase assembly 14. In an embodiment, the lower portion 61 has an integrally formed securing member 64. In an embodiment as seen from the top view, the lower portion is circular in shape. The middle portion 62 comprises of an oil filter 65 including a mesh for removing foreign substances contained in the lubrication oil. The middle portion is cylindrical in shape when seen from the side view. The oil filter 65 is mounted on the securing member 64. The upper portion 63 houses an oil outlet pipe 66 integrally formed in the upper portion 63. In an embodiment, the upper portion is conical in shape. The oil outlet pipe 66 carries the filtered oil from the oil sump 51 and feeds it into to an inlet port 53 of the oil pump. The inlet port and the oil path are interchangeably used. As, the inlet port 53 is part of the oil path 53. The oil outlet pipe 66 is disposed above the oil filter 65 and is integrally formed with it. The oil filter 65 is thus provided between the securing member 64 and the oil outlet pipe 66 and comprises of a mesh inserted therein the middle portion 62 for removing foreign undesirable substances from the lubrication oil.
[00021] In an embodiment, the securing member 64 is provided with an engaging portion 70 disposed on an outer surface of said securing member, wherein said engaging portion 70 is capable of engaging with a fastening tool for assembling said oil filtering device 60 to said crankcase assembly 14. In the present embodiment, as depicted, the engaging portion 70 is having a hexagonal cross-section that is capable of engaging with a conventional wrench for ease of assembly.
[00022] In other words, the oil filtering device 60 is detachably-attachable to a crankcase assembly 14 of said internal combustion engine 100 at the drain hole 47 through the securing member 64 that is provided with plurality of threaded portions. The lubrication oil from an oil sump 51 passes through the oil filter 65 to an oil path 53 through the oil out let pipe 66. As, the oil filtering device 60 includes the oil filter 65, the possibility of filter being missed during assembly is eliminated. Further, the securing member 64 is integrated with one end portion E1 of said oil filter 65 and said oil outlet pipe 66 is integrated with other end portion E2 of said oil filter 65. Therefore, the oil filtering device 60 provided optimum layout that improves the ground clearance. Further, the oil outlet pipe 66 and the oil path 53 are properly aligned thereby improving assembly.
[00023] As shown in FIG. 4 (b), the lower portion 61 has a groove 67. In an embodiment, the groove 67 is provided at centre of the lower portion when viewed from the top. The groove 67 is co-axial to the oil outlet pipe 66 and have a magnetic material 68 disposed therein. The magnetic material attracts the tiny pieces of metal or alloy that may enter the lubrication channel and captures them in the lower portion.
[00024] FIG. 5 shows the assembly of the oil filtering device in the crankcase assembly 14. The ceiling of the oil sump 51 comprises of a strainer groove 52. In an embodiment, the strainer groove is formed in the left casing 40 above the oil sump.The upper portion of the oil filtering device has a stepped construction to receive and rest an O-ring 49. In an embodiment, a stepped surface 71 is provided in the upper portion 63 of the oil filtering device. The O-Ring 49 is inserted through the outer diameter of the oil outlet pipe 66 and then the oil outlet pipe 66 is inserted into the strainer groove 52 from below. The O-ring 49 seals the oil outlet pipe 66 for any oil leak back to the oil sump 51 and fends off against any air entry. The oil outlet pipe 66 is thus connected to the inlet port 53 of the oil pump through the strainer groove 52. After entering the inlet port 53, the oil is taken to the rest of the lubrication channel. A drain hole 47 is provided in the oil sump 51. The drain hole 47 is bigger in dimension than, and co-axial to, the strainer groove 52. During servicing or when required, the lubrication oil can be drained from the drain hole 47. The lower portion 64 of the oil filtering device 60 is configured to secure the oil filtering device to the drain hole 47.
[00025] According to an aspect of the present invention, the oil filtering device 60 is detachably screwed to the crankcase assembly 14 of the internal combustion engine with the help of the securing member 64. A sealing member 81 is located on the radial surface of the lower portion around the securing member to seal the oil from leaking out of the oil filtering device 60. The oil filtering device is first inserted into the oil sump 51 from the bottom through the drain hole 47. A portion of the oil outlet pipe 66 is inserted and sealed into the strainer groove 52. The entire oil filtering device is then rotated through the securing member 64 which is still placed exteriorly with respect of the drain hole 47. The securing member then secures the oil filtering device against the drain hole 47. In an embodiment, the securing member 64 and the drain hole 47 are threaded.
[00026] The oil filtering device is compact due to its single piece construction which saves space. The overall reduction in the length achieved in the oil filtering device helps to achieve better ground clearance as the width of the lower portion, and more specifically, the securing member of the oil filtering device is reduced.
[00027] The oil filtering device is made of any material from a group consisting of metal, alloy and plastic resin, or a combination thereof. This arrangement makes the oil filtering device cost and weight effective.
[00028] Further, the oil filtering device 60 according to the present invention is a standalone device. The oil outlet pipe 66, the oil filter 65 including the mesh and the securing member 64 are integrally formed. Thus, the oil filtering device 60 is assembled to the crankcase assembly as one unit thereby reducing the number of parts. As one unit, it is easy to assemble the oil filtering device 60 during engine assembly. It also removes the chances of forgetting to insert oil filter during engine servicing after the lubrication oil is drained out because the drain hole is closed with the help of the standalone oil filtering device secured to the crankcase assembly as one unit. Thus, the oil filtering device according to the present invention helps in reducing the servicing time and improves serviceability. By just uncoupling the securing member, the entire oil filtering device is taken out of the crankcase assembly and the lubrication oil is drained out of the oil sump.
[00029] Still further, the oil filtering device as proposed is retrofittable in existing engines in a cost effective way. The existing plurality of components in the engine are replaced with the present oil filtering device, which is secured to the crankcase assembly as described. Another embodiment of the invention is possible where the upper portion and the middle portion of the oil filtering device are integrally formed, and the lower portion comprising the securing member is separately affixed to the bottom surface of the middle portion resulting in one oil filtering device unit which can be assembled with the engine.
[00030] The present invention is thus briefly described. It will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the present invention.
,CLAIMS:I/We claim:
1. An internal combustion engine (100)comprising:
a crank case assembly (14) comprising an oil sump (51) and an oil path (53); and
an oil pump (58) for circulating lubrication oil from said oil sump (51) through said oil path (53),
wherein,
said oil filtering device (60) is detachably-attached to said crankcase assembly (14) through a securing member (64), lubrication oil from said oil sump (51) passes through an oil filter (65) to said oil path (53) through an oil out let pipe (66), wherein
said securing member (64) is integrated with one end portion (E1) of said oil filter (65) and said oil outlet pipe (66) is integrated with other end portion (E2) of said oil filter (65).
2. The internal combustion engine (100) as claimed in claim 1, wherein said securing member (64) is provided with plurality of threads for securing said oil filtering device (60) to a drain hole (47) provided on a lower surface of said crankcase assembly (14).
3. The internal combustion engine (100) as claimed in claim 1, wherein said oil filter (65) includes annularly disposed mesh portion and the mesh portion is integrally formed with the oil filter (65).
4. The internal combustion engine (100) as claimed in claim 1, wherein the securing member (65) is provided with a groove (67) capable of accommodating a magnetic material (68) therein, said groove (67) is co-axial to said oil outlet pipe (66).
5. The internal combustion engine (100) as claimed in claim 1, wherein the oil outlet pipe (66) is functionally connected to an inlet port (53) of the oil pump (58).
6. The internal combustion engine (100) as claimed in claim 1 or claim 5, wherein the oil outlet pipe (66) is provided with a stepped surface (71)to receive an O-Ring (49) whereby said the oil outlet pipe (66) is connected to the inlet port (53) of the oil pump through a strainer groove(52).
7. The internal combustion engine (100) as claimed in any preceding claims, wherein the drain hole (47) and the strainer groove (52) are co-axially disposed.
8. An oil filtering device (60) for working in conjunction with an internal combustion engine (100), said oil filtering device (60) comprising:
a securing member (64) for securing said oil filtering device (60) to a crankcase assembly (14) of said internal combustion engine (100);
an oil filter (65) for filtering lubrication oil available in an oil sump (51) of said internal combustion engine (100); and
an oil outlet pipe (66) connecting said oil filter (65) to an oil path (53) of said internal combustion engine (100),
wherein,
said oil filtering device (60) is detachably-attachable to a crankcase assembly (14) of said internal combustion engine (100) through the securing member (64), lubrication oil from an oil sump (51) passes through the oil filter (65) to an oil path (53) through the oil out let pipe (66), wherein
said securing member (64) is integrated with one end portion (E1) of said oil filter (65) and said oil outlet pipe (66) is integrated with other end portion (E2) of said oil filter (65).
9. The oil filtering device (60) as claimed in claim 8, wherein the oil outlet pipe (66) is provided with a stepped surface (71) to receive an O-ring.
10. The oil filtering device (60) as claimed in claim 8, wherein said securing member (64) is provided with an engaging portion (70) disposed on an outer surface of said securing member, wherein said engaging portion (70) is capable of engaging with a fastening tool for assembling said oil filtering device (60) to said crankcase assembly (14).