Description:FIELD OF THE INVENTION
[001] The present invention generally relates to an internal combustion engine. More particularly, the present invention relates to an internal combustion engine for a motor vehicle.

BACKGROUND OF THE INVENTION
[002] Generally, in conventional motor vehicles, the internal combustion engine layouts use ball bearings in the crankshaft. All the combustion loads are transferred to the crankshaft main bearing. In the crankshaft main bearing, high friction is observed in existing engine layouts, which leads to high crankshaft noise and less reliability and durability of the engine. In addition, conventional engine layouts especially for two wheelers, generally use ball bearing diameters of 72 mm on the left side of the crankshaft and of 55 mm on the right side of the crankshaft, thus making the engine layouts larger and bulkier.
[003] To provide adequate lubrication to the ball bearings, some conventional engine layouts use separate oil sumps and separate oil cavities for crankshaft lubrication and for transmission system. Consequently, two separate oil pumps are required for maintaining lubrication to the crankshaft and the transmission. In other conventional engine layouts, dedicated grooves need to be created for providing lubrication to different engine parts, thus increasing cost and complexity of manufacturing the engine.
[004] To address the issue of usage of larger sized ball bearings, some existing engine layouts use shell bearings for supporting the crankshaft. However, shell bearings require dedicated pressurised lubrication mechanisms for adequate lubrication. Conventional engine layouts lack the pressurised lubrication mechanisms that are capable of sufficiently lubricating the shell bearings. In absence of adequate lubrication, the shell bearings are subjected to increased temperatures and higher friction levels, which may ultimately lead to seizure of the crankshaft, high noise and vibration, and lowered durability and reliability.
[005] Thus, there is a need in the art for an internal combustion engine which addresses at least the aforementioned problems.

SUMMARY OF THE INVENTION
[006] In one aspect, the present invention is directed towards an internal combustion engine. The internal combustion engine has a crankcase having a left crankcase half and a right crankcase half. A crankshaft is rotatably supported in the crankcase. An oil pump is configured to discharge oil stored in an oil sump of the crankcase. The crankcase has a pair of bearings that are provided in the crankcase for rotatably supporting the crankshaft. The pair of bearings have a left side bearing provided in the left crankcase half and a right side bearing provided in the right crankcase half. An oil gallery extends in the right crankcase half and is configured for receiving oil from the oil pump. The oil gallery includes a first groove. A first oil path structure extends from the first groove and is configured to receive oil from the first groove to transmit a part of the oil towards a camshaft and a piston jet, and a part of the oil towards the right side bearing. The right crankcase half includes a second groove provided downstream of the first groove in the oil gallery. A second oil path structure extends from the second groove. The second oil path structure extends from the right crankcase half to the left crankcase half and is configured to receive oil from the second groove to transmit the oil to the left side bearing. The right crankcase half also includes a third groove provided downstream of the second groove in the oil gallery. The third groove is configured to supply oil to a transmission side lubrication passage extending from the right crankcase half to the left crankcase half and being configured to provide oil to at least a drive shaft of the internal combustion engine.
[007] In an embodiment of the invention, the left side bearing and the right side bearing includes shell type bearings.
[008] In a further embodiment of the invention, the first groove is located at a cylinder block seating surface on the crankcase. Herein, the cylinder block seating surface is configured to receive a cylinder block of the internal combustion engine.
[009] In a further embodiment of the invention, the first oil path structure has a channel that extends from the cylinder block seating surface to the right side bearing. The channel is configured to transmit oil to the right side bearing.
[010] In a further embodiment of the invention, the internal combustion engine has a cover clutch provided for covering the right crankcase half. The oil gallery is located at a joining surface of the cover clutch and the right crankcase half.
[011] In a further embodiment of the invention, the internal combustion engine has an oil cooler that is configured for cooling the oil discharged by the oil pump. The oil gallery receives the oil from the oil pump via the oil cooler.
[012] In a further embodiment of the invention, the internal combustion engine has an oil filter. The oil filter is provided for filtering the oil being received by the oil gallery from the oil pump.

BRIEF DESCRIPTION OF THE DRAWINGS
[013] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 illustrates a perspective view of a part of an internal combustion engine, in accordance with an embodiment of the present invention.
Figure 2 illustrates a perspective view of the part of the internal combustion engine illustrated in Figure 1 without a crankcase, in accordance with an embodiment of the present invention.
Figure 3 illustrates a right side view of the internal combustion engine, in accordance with an embodiment of the present invention.
Figure 4 illustrates a right side view of a right crankcase half of the internal combustion engine, in accordance with an embodiment of the present invention.
Figure 5 illustrates a top view of the internal combustion engine, in accordance with an embodiment of the present invention.
Figure 6 illustrates a sectional view of the right crankcase half along section B-B shown in Figure 5, in accordance with an embodiment of the present invention.
Figure 7A illustrates a right side view of the right crankcase half, in accordance with an embodiment of the present invention.
Figure 7B illustrates a left side view of the right crankcase half, in accordance with an embodiment of the present invention.
Figure 7C illustrates a right side view of a left crankcase half, in accordance with an embodiment of the present invention.
Figure 8 illustrates another right side view of the right crankcase half, in accordance with an embodiment of the present invention.
Figure 9 illustrates a section view of the internal combustion engine along section A-A illustrated in Figure 8, in accordance with an embodiment of the present invention.
Figure 10 illustrates another right side view of the left crankcase half, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
[014] The present invention relates to an internal combustion engine. The internal combustion engine of the present invention is typically used in a vehicle such as a two wheeled vehicle, or a three wheeled vehicle, or a four wheeled vehicle, or other multi-wheeled vehicles as required. However, it should be understood that the internal combustion engine as illustrated may find its application in any non-automotive application using an internal combustion engine.
[015] Figure 1 illustrates a perspective view of a part of an internal combustion engine 100 in accordance with an embodiment of the invention. As illustrated in Figure 1, the internal combustion engine 100 has a crankcase 110. The crankcase 110 has a split construction wherein the crankcase 110 has a left crankcase half 110L and a right crankcase half 110R (shown in Figure 4). The left crankcase half 110L and the right crankcase half 110R align with each other and are attached to each other to form the crankcase 110. The internal combustion engine 100 further has a crankshaft (not shown). The crankshaft is rotatably supported in the crankcase 110. The crankshaft is connected to a piston of the internal combustion engine 100 and translational motion of the piston in a cylinder of the internal combustion engine 100 is converted to rotational motion by the crankshaft. The crankshaft is further connected to a drive shaft 116. In an embodiment, the rotation of the crankshaft is thereby transferred to a transmission mechanism to provide motive power for the vehicle through the drive shaft 116.
[016] As illustrated in Figure 1 and further illustrated in Figure 2 and Figure 3, the internal combustion engine 100 has an oil pump 130. The oil pump 130 is configured to discharge oil stored in an oil sump of the crankcase 110. In an embodiment, as illustrated in Figures 1, 2 and 3, the internal combustion engine 100 has an oil cooler 132. Since the lubrication oil performs dual function of lubrication and heat exchange or cooling of the components of the internal combustion engine 100, the oil needs to be cooled. For that, the oil pump 130 supplies oil to the oil cooler 132 and the oil cooler 132 is configured for cooling the oil discharged by the oil pump 130. The internal combustion engine 100 further has an oil filter 134 that is provided for filtering the oil being received from the oil cooler 132. Thus, as illustrated by dashed arrows in Figure 3, the lubrication oil is taken from the oil sump, and is pumped by the oil pump 130 towards the oil cooler 132. The lubrication oil is then cooled by the oil cooler 132 and then sent back towards the oil filter 134, after which the filtered oil is circulated through the crankcase 110. After the lubrication oil is circulated through the crankcase 110, the hot oil is received at the oil sump, after which the oil pump sends the oil towards the oil cooler 132 and the cycle continues.
[017] As referenced in Figure 1 and 2, the crankcase 110 comprises a pair of bearings 120. The pair of bearings 120 are provided in the crankcase 110 for rotatably supporting the crankshaft. Thus, the rotating crankshaft is appropriately supported within the crankcase 110. Herein, the pair of bearings 120 have a left side bearing 120L that is provided in the left crankcase half 110L, and a right side bearing 120R that is provided in the right crankcase half 110R. In an embodiment, the left side bearing 120L and the right side bearing 120R include shell type bearings. In an embodiment, the diameter of shell type left side bearing 120L and shell type right side bearing 120R is 38 mm. Thus, in the present invention, the requirement of bulky and large ball bearings is eliminated.
[018] Reference is now made to Figure 4, wherein as illustrated, the crankcase 110 includes an oil gallery 140. The oil gallery 140 extends in the right crankcase half 110R. The oil gallery 140 is configured for receiving oil from the oil pump 130. In an embodiment, the oil gallery 140 receives the oil from the oil pump 130 via the oil cooler 132 and the oil filter 134 as explained hereinbefore. In an embodiment, the internal combustion engine 100 comprises a cover clutch that is provided for covering the right crankcase half 110R. In that, the oil gallery 140 is located at a joining surface of the cover clutch and the right crankcase half 110R.
[019] As further illustrated in Figure 4, the oil gallery 140 includes a first groove 150 provided in the right crankcase half 110R, wherein the first groove 150 receives a part of the oil flowing in the oil gallery 140. As referenced in Figure 5, in an embodiment, the first groove 150 is located at a cylinder block seating surface 118 on the crankcase 110. The cylinder block seating surface 118 is configured to receive a cylinder block (not shown) of the internal combustion engine 100. The transmitting of oil from the oil gallery 140 to the first groove 150 is illustrated in dashed arrows. Reference is made to Figure 2, wherein as illustrated, the crankcase 110 comprises a first oil path structure 152. The first oil path structure 152 extends from the first groove 150 and the first oil path structure 152 is configured to receive oil from the first groove 150 and transmit a part of the oil towards a camshaft 112 and a piston jet 114 of the internal combustion engine 100. The piston jet 114 is configured to spray oil towards a bottom portion of the piston, thereby providing lubrication oil to the piston. This part of the oil thereby cools the piston through the piston jet 114, the cylinder and the camshaft 112 of the internal combustion engine 100. The other part of the oil entering the first groove 150 is transmitted towards the right side bearing 120R provided in the right crankcase half 110R.
[020] Figure 6 illustrates a sectional view of the internal combustion engine 100 along section B-B (shown in Figure 5). In the embodiment illustrated in Figure 6, for transmitting oil from the first groove 150 to the right side bearing 120R, the first oil path structure 152 comprises a channel 154 that extends from the cylinder block seating surface 118 to the right side bearing 120R. As illustrated by dashed arrows, oil from the oil gallery 140 enters the first groove 150 and is then transmitted to the right side bearing through the channel 154 extending between the cylinder block seating surface 118 and the right side bearing 120R. Thus, the present invention ensures provision of sufficient lubrication to the right side bearing 120R. The oil after lubricating the right side bearing 120R is transmitted to a crankpin for lubrication, and thereafter the oil returns to the oil sump.
[021] Reference is made to Figure 4 and Figure 8, wherein as illustrated the right crankcase half 110R comprises a second groove 160. The second groove 160 is provided downstream of the first groove 150 in the oil gallery 140. Thus, part of the oil left in the oil gallery 140 after transmitting to the first groove 150 enters the second groove 160.
[022] As referenced in Figures 7A, 7B and 7C, the oil travelling in the oil gallery 140 in the right crankcase half 110R enters the left crankcase half 110L by means of the second groove 160. For transmitting oil from the second groove 160 on the right crankcase half 110R to the left crankcase half 110L, the crankcase 110 comprises a second oil path structure 162. The second oil path structure 162 extends from the second groove 160.
[023] Figure 9 illustrates a sectional view of the internal combustion engine 100 along section A-A (shown in Figure 8). As illustrated in Figure 9, the second oil path structure 162 extends from the right crankcase half 110R to the left crankcase half 110L. Therefore, the second oil path structure 162 is configured to receive oil from the second groove 160 to transmit the oil to the left side bearing 120L being provided in the left crankcase half 110L. The transmitting of the oil from the second groove 160 towards the left side bearing 120L through the second oil path structure 162 is depicted in dashed arrows in Figure 9 and Figure 10. The oil lubricating the left side bearing 120L, is thereafter returned to the oil sump. In an embodiment, to ensure assembly of the left crankcase half 110L to the right crankcase half 110R, the second oil path structure 162 is configured such that portion of the second oil path structure 162 in the left crankcase half 110L aligns with the portion of the second oil path structure 162 in the right crankcase half 110R, thereby aligning the left crankcase half 110L and the right crankcase half 110R for assembly.
[024] The part of the oil still remaining in the oil gallery 140 after transmitting to the second groove 160 is forwarded towards a third groove 170. Reference is made to Figure 4 and Figure 8, wherein as illustrated, the right crankcase half 110R further has the third groove 170. The third groove 170 is provided downstream of the second groove 160 in the oil gallery 140. Further, the third groove 170 is configured to supply oil to a transmission side lubrication passage 172 (shown in Figure 2). Herein, the transmission side lubrication passage 172 extends from the right crankcase half 110R to the left crankcase half 110L. The transmission side lubrication passage 172 is configured to provide oil to at least the drive shaft 116 of the internal combustion engine 100. In an embodiment, the transmission side lubrication passage 172 is configured to provide oil to the drive shaft 116 and all other transmission components of the internal combustion engine 100.
[025] Advantageously, in the present invention, sufficient lubrication is provided to at least the piston, the cylinder, the camshaft, the right side bearing and the crankpin through the first groove. Further, sufficient lubrication is provided to the left side bearing through the second groove and the second oil path structure. Furthermore, sufficient lubrication is provided to the drive shaft and other transmission components of the internal combustion engine through the third groove. Thus, the present invention ensures that lubrication is provided to all parts of the internal combustion engine.
[026] Further, the present invention provides for usage of shell type bearings for supporting the crankshaft instead of the conventional ball bearings, along with provision of lubrication that is capable of supporting the usage of shell type bearings. In the present invention, the supply of oil to the right side shell type bearing through the first groove, and to the left side shell type bearing through the second groove allow for pressurised oil to be supplied to the shell type bearings, thereby allowing shell type bearings to be used. The present invention allows for oil pump to supply oil to the left side bearing and the right side bearing at relatively higher pressures. The usage of shell type bearings and adequate lubrication eliminates the need of large and bulky ball bearings which makes the engine lighter and more compact, which then has an improving effect on the performance and economy of the internal combustion engine. This is achieved without requiring complex engine configuration, which lowers cost and complexity of manufacturing the engine.
[027] In addition, provision of adequate lubrication to all parts of the internal combustion engine ensures that there is less noise, the durability of the engine is increased, and the internal combustion engine stays reliable for a longer period of time.
[028] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

List of Reference Numerals
100: Internal Combustion Engine
110: Crankcase
110L: Left Crankcase Half
110R: Right Crankcase Half
112: Camshaft
114: Piston Jet
116: Drive Shaft
118: Cylinder Block Seating Surface
120: Pair of Bearings
120L: Left Side Bearing
120R: Right Side Bearing
130: Oil Pump
132: Oil Cooler
134: Oil Filter
140: Oil Gallery
150: First Groove
152: First Oil Path Structure
154: Channel
160: Second Groove
162: Second Oil Path Structure
170: Third Groove
172: Transmission Side Lubrication Passage

, Claims:1. An internal combustion engine (100), the internal combustion engine (100) comprising:
a crankcase (110), the crankcase having a left crankcase half (110L) and a right crankcase half (110R);
a crankshaft, the crankshaft being rotatably supported in the crankcase (110);
an oil pump (130), the oil pump (130) being configured to discharge oil stored in an oil sump of the crankcase (110);
wherein, said crankcase (110) comprising:
a pair of bearings (120), the pair of bearings (120) being provided in the crankcase (110) for rotatably supporting the crankshaft, the pair of bearings (120) having a left side bearing (120L) being provided in the left crankcase half (110L) and a right side bearing (120R) being provided in the right crankcase half (110R);
an oil gallery (140), the oil gallery (140) extending in the right crankcase half (110R), the oil gallery (140) being configured for receiving oil from the oil pump (130), wherein said oil gallery (140) includes a first groove (150);
a first oil path structure (152), the first oil path structure (152) extending from the first groove (150), the first oil path structure (152) being configured to receive oil from the first groove (150) and transmit a part of the oil towards a camshaft (112) and a piston jet (114) of the internal combustion engine (100), and a part of the oil towards the right side bearing (120R) being provided in the right crankcase half (110R);
wherein the right crankcase half (110R) includes a second groove (160), the second groove (160) being provided downstream of the first groove (150) in the oil gallery (140);
a second oil path structure (162), the second oil path structure (162) extending from the second groove (160), the second oil path structure (162) extending from the right crankcase half (110R) to the left crankcase half (110L), the second oil path structure (162) being configured to receive oil from the second groove (160) to transmit the oil to the left side bearing (120L) being provided in the left crankcase half (110L); and
wherein the right crankcase half (110R) includes a third groove (170), the third groove (170) being provided downstream of the second groove (160) in the oil gallery (140), the third groove (170) being configured to supply oil to a transmission side lubrication passage (172), the transmission side lubrication passage (172) extending from the right crankcase half (110R) to the left crankcase half (110L) and being configured to provide oil to at least a drive shaft (116) of the internal combustion engine (100).

2. The internal combustion engine (100) as claimed in claim 1, wherein the left side bearing (120L) and the right side bearing (120R) includes shell type bearings.

3. The internal combustion engine (100) as claimed in claim 1, wherein the first groove (150) being located at a cylinder block seating surface (118) on the crankcase (110), the cylinder block seating surface (118) being configured to receive a cylinder block of the internal combustion engine (100).

4. The internal combustion engine (100) as claimed in claim 3, wherein the first oil path structure (152) comprises a channel (154), the channel (154) extending from the cylinder block seating surface (118) to the right side bearing (120R), the channel (154) being configured to transmit oil to the right side bearing (120R).

5. The internal combustion engine (100) as claimed in claim 1, comprising a cover clutch being provided for covering the right crankcase half (110R), and the oil gallery (140) being located at a joining surface of the cover clutch and the right crankcase half (110R).

6. The internal combustion engine (100) as claimed in claim 1, comprising an oil cooler (132), said oil cooler (132) being configured for cooling the oil discharged by the oil pump (130), and the oil gallery (140) receives the oil from the oil pump (130) via the oil cooler (132).

7. The internal combustion engine (100) as claimed in claim 1, comprising an oil filter (134), said oil filter (134) being provided for filtering the oil being received by the oil gallery (140) from the oil pump (130).