Description:TECHNICAL FIELD

[0001] The present subject matter relates generally to an internal combustion engine. More particularly but not exclusively the present subject matter relates to lubrication of one or more parts of the internal combustion engine.

BACKGROUND

[0002] Nowadays, with the advancement in the technology, a variable compression ratio is used to adjust/change a compression ratio of an internal combustion engine. The internal combustion engines employing variable compression ratio permits a volume above a piston of the engine at a top dead centre to be changed/varied. The internal combustion engines running at higher loads need lower compression ratios to increase power, whereas the internal combustion engines running at lower loads need higher ratios to increase the efficiency of the internal combustion engine. The variable compression ratio facilitates in lower the fuel consumption while increasing the efficiency of the internal combustion engine.
[0003] A variable compression ratio is used to increase the efficiency of an internal combustion engine while ensuring a lower fuel consumption. The Variable Compression Ratio (hereinafter to be referred as ‘VCR’) is a ratio by which fuel/air mixture is compressed before the fuel/air mixture is ignited. There are different ways to vary the compression ratio already known in the art. In a known prior art, a Saab Variable Compression (SVC) lowers a cylinder head closer to a crankshaft, which alters the compression ratio. It is done by replacing a typical one part engine block with a two part unit, with the crankshaft in a lower block and the cylinders in an upper portion. The drawback of such mechanism is that moving mass of SaaB VCR is very high. Also, complex pivot arrangement is used to achieve changes in compression ratio.
[0004] In yet another known art, the piston top exceeds a top of the cylinder by a given amount, this volume must be subtracted from the combustion chamber volume, which will increase the compression ratio. However, the piston position directly affects piston-to-head clearance, so caution and precision is to be taken at the time of manufacturability so that the piston-to-head clearance stays within the specification and is not affected, which may lead to a defective engine. Achieving this piston-to-head clearance is very difficult during manufacturability and there are high chances of manufacturing of defective parts.
[0005] In yet another known art, a VCR system is provided which includes one or more gears assembled in a crankshaft assembly. The one or more gear includes an eccentric gear which is located between a piston and a crank pin. A VCR gear, the eccentric gear, and an intermediate gear are connected together to form the VCR system. To vary the compression ratio, the VCR gear is adjusted, the eccentric gear rotates, which further rotates the piston. The piston moves slightly up and down due to the movement of the eccentric gear. This up and down movement changes the volume and thus changes the effective compression ratio in the combustion chamber. However, these gears need to be lubricated for durability, as with time, the gears will wear and tear. The working of these gears of the VCR system may get affected and may not work smoothly if not lubricated properly.
[0006] The above-mentioned problems are very critical and therefore, effective lubrication of the gears of the VCR system is required to be carried out for proper functioning of the internal combustion engine with variable compression ratio. Thus, there is a need to overcome the above-mentioned problems and other problems of known art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The details are described with reference to an embodiment of an internal combustion engine along with the accompanying diagrams. The same numbers are used throughout the drawings to reference similar features and components.
[0008] Figure 1 exemplarily illustrates a cross- sectional side view of the internal combustion engine.
[0009] Figure 2(a) exemplarily illustrates a crankshaft along with a connecting rod and one or more gears.
[00010] Figure 2(b) exemplarily illustrates a VCR shaft and the one or more gears.
[00011] Figure 3 exemplarily illustrates a localized cross sectional side view of the crankshaft with the one or more gears.
[00012] Figure 4 exemplarily illustrates a third gear having a first intermediate gear and a second intermediate gear.

DETAILED DESCRIPTION

[0001] An objective of the present subject matter is to provide an effective and efficient lubrication of gears of a VCR system of an internal combustion engine, which maintains the durability of the system and thus increases the life of the system while avoiding failure of the gears and reduce the friction while the gears of the VCR system is in operation. The embodiments of the present invention will now be described in detail with reference to an internal combustion engine along with the accompanying drawings. However, the present invention is not limited to the present embodiments. The present subject matter is further described with reference to accompanying figures. Wherever convenient, the same reference numbers are used throughout the drawings to refer to the same or like parts. While examples and features of disclosed principles are described herein, modifications, adaptations, and other implementations are possible without departing from the scope of the disclosed embodiments. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[0002] As per an aspect of the subject matter, an internal combustion engine comprising a crankcase, a crankshaft, one or more connecting rod, and a piston. The crankshaft is supported by said crankcase and said crankshaft is rotatable about a crankshaft axis. The one or more connecting rod includes a first end and a second end. The piston is rotatably connected to said first end of said one or more connecting rod. One or more gear members being disposed on said crankshaft and said one or more gear members being connected in a transmission path forming a variable compression ratio system. An oil path being provided in said crankshaft, said oil path being provided with a forced spray mechanism configured to lubricate said one or more gears of said variable compression ratio system.
[0003] As per an aspect of the subject matter, the one or more gears include a first gear, a second gear, and a third gear, said first gear, said second gear, and said third gear are connected in said transmission path forming said variable compression ratio system. The first gear is disposed between said piston and a crank pin. The crank pin is supported by said crankshaft. The second gear and the third gear are supported by said crankshaft, said first gear and said second gear are configured to mesh with said third gear.
[0004] As per an aspect of the subject matter, the first gear is an eccentric gear. The second gear is a VCR (Variable Compression Ratio) gear. The third gear includes a first intermediate gear and a second intermediate gear.
[0005] As per an aspect of the subject matter, the oil path includes a first path, a second path, and a third path. The first path is configured to receive oil for lubrication from a pump system. The second path and the third path being configured to receive oil coming from the first path. The oil in the second path lubricates a bearing of said crank pin of the crankshaft. The oil in the third path is configured to lubricate the one or more gears of said variable compression ratio system.
[0006] As per an aspect of the subject matter, the third path includes a first end and a second end, the first end of the third path is connected to the first path through an oil path extension. The second end being provided with an oil jet nozzle to facilitate forced lubrication of said one or more gears of the variable compression ratio system.
[0007] As per an aspect of the subject matter, the third path is provided with said oil jet nozzle configured to direct oil towards said first intermediate gear of said third gear. The first intermediate gear includes one or more openings, the one or more openings allows oil to reach an interface between said second gear and said second intermediate gear.
[0008] As per an aspect of the subject matter, the third path is provided with said oil jet nozzle to facilitate forced lubrication by means of splashed lubrication of said one or more gears of said variable compression ratio system.
[0009] As per an aspect of the subject matter, the oil path is provided on one of a left side crankshaft or a right side crankshaft of said internal combustion engine.
[00010] As per an aspect of the subject matter, the first oil path is configured to have a first width and the third oil path is configured to have a second width. The first width being greater than said second width.
[00011] Fig.1 exemplarily illustrates exemplarily illustrates a cross- sectional side view of the internal combustion engine 100. Fig. 1 shows an embodiment of a four-stroke internal combustion engine 100 according to the invention. The engine 100 comprises a crankcase 108 which supports a crankshaft 104 through a crankshaft bearing 106. The crankcase 108 is divided into a left-side crankcase 108a and a right-side crankcase 108b. The crankshaft 104 includes a crankpin 110 which is located between two crank arms (not shown) and is rotatable with respect to an engine block 102 about a crankshaft axis 112. The crankshaft 104 includes at least a central main portion, the crankpin 110 and a crankshaft web, where the crankshaft web (not shown) is located between the central main portion and the crankpin 110. One or more piston 116 is rotatably connected to a first end of the one or more connecting rod 114. The engine 100 comprises an eccentric member which is rotatably mounted on the crankpin 110. The eccentric member is provided with a bearing portion which is disposed eccentrically with respect to the crankpin 110. The bearing portion has an outer circumferential wall which bears a big end of one or more connecting rod 114. One or more piston 116 is rotatably connected to a first end of the one or more connecting rod 114.
[00012] Fig.2(a) exemplarily illustrates the crankshaft 104 along with the connecting rod 114 and one or more gears 118 which shows a part of the embodiment of Fig. 1 in a more schematic way, in which parts are omitted for brevity. Fig.2(b) exemplarily illustrates a VCR shaft 134 and the one or more gears 118. The internal combustion engine 100 includes one or more gears 118 being disposed on the crankshaft 104. The one or more gears 118 forms a VCR (variable compression ratio) system of the internal combustion engine 100. The one or more gears 118 are connected in a transmission path forming the VCR system. The one or more gears 118 include a first gear 120, a second gear 122, and a third gear 124. The first gear 120, the second gear 122, and the third gear 124 are connected in the transmission path forming said variable compression ratio system. The first gear 120 is disposed between the connecting rod 114 of the piston 116 (shown in fig.1) and the crank pin 110 (shown in fig.1), the crank pin 110 is supported by the crankshaft 104. In an embodiment, the first gear 120 is an eccentric gear which is an external gear and which meshes with a second gear 122. In an embodiment, the second gear 122 is a VCR gear. The second gear 122 is attached to an end of a VCR shaft 134. In an embodiment, the second gear 122 is integrated to the end of the VCR shaft 134. In an embodiment, the third gear 124 is an intermediate gear which is also an external gear. The third gear 124 includes a first intermediate gear 124a and a second intermediate gear 124b. The second gear 122 and the third gear 124 form a common external gear which is rotatably mounted to the crankshaft 104 about a common axis of rotation which extends parallel to the crankshaft axis 112. The combination of first gear 120, the second gear 122, and the third gear 124 facilitates in increasing the compression ratio to reduce fuel consumption.
[00013] Fig.3 exemplarily illustrates a localized cross sectional side view of the crankshaft 104 with the one or more gears 118. As per an embodiment of the present invention, the one or more gears 118 of the VCR system needs to be lubricated for proper functioning and to avoid any failure of the one or more gears 118, to solve the above mentioned problem, one or more oil path 126 has been provided in the internal combustion engine 100. The one or more oil path 126 is provided in the crankshaft 104 of the internal combustion engine 100. In the present embodiment, the one or more oil path 126 includes a first path 126a, a second path 126b, and a third path 126c. However, it is to be understood that there is no limitation on the number of oil path 126 is not restricted and can be less or more than three oil path 126, as mentioned in the embodiment above. The first path 126a is configured to receive oil for lubrication from a pump system (not shown). The second path 126b and the third path 126c is configured to receive oil coming from the first path 126a. The oil from the first path 126a moves in an inclined upward direction in the second path 126b to lubricate the bearing 106 of the crank pin 110 of the crankshaft 104 and the first gear 120 of the VCR system. The oil in the third path 126c comes from an oil path extension 128 formed in the first path 126a. In an embodiment, the oil path extension 128 is inclinedly placed partially inside the first path 126a. The oil path extension 128 being inclinedly placed and is in line with the second path 126b. The third path 126c is configured to lubricate said one or more gears 118 of said VCR system.
[00014] In the present embodiment, the third path 126c includes a first end and a second end. The first end of the third path 126c is connected to the first path 126a through the oil path extension 128. The second end being provided with an oil jet nozzle 130 to facilitate forced lubrication of said one or more gears 118 of said variable compression ratio system. In an embodiment, the third path 126c is provided with the oil jet nozzle 130 to facilitate forced lubrication by means of splashed lubrication of the one or more gears 118 of the VCR system. However, any other type of forced lubrication can be employed for lubrication. In an embodiment, the oil path 126 is provided on one of a left side crankshaft 104a or a right side crankshaft 104b of said internal combustion engine 100 (shown in fig.1), depending on the design requirements. The first path 126a is configured to have a first width and the third path 126c being configured to have a second width. The first width of the first path 126a being greater than the second width of the third path 126c. The oil jet nozzle 130 can be any type of jet nozzle available in the art. In the present embodiment, the oil jet nozzle 130 is press fitted in a crankshaft web face (not shown).
[00015] Fig.4 exemplarily illustrates the third gear 124 having the first intermediate gear 124a and the second intermediate gear 124b. The first intermediate gear 124a and the second intermediate gear 124b are disposed side by side. The first intermediate gear 124a includes one or more openings 132 that allows oil splashed from the oil jet nozzle 130 (shown in fig.2) to pass from the one or more openings 132 of the first intermediate gear 124a to lubricate an interface between the second gear 122 and the second intermediate gear 124b, which is otherwise very difficult to lubricate.
[00016] The present invention provides one or more lubrication path for the one or more gears 118 to avoid any failure of the VCR gears while in operation. The oil path 126 provided with a forced spray mechanism is configured to lubricate the one or more gears 118 of the variable compression ratio system. The lubrication of the one or more gears 118 will improve the durability and life of the one or more gears 118 of the VCR system. Lubricating the one or more gears 118 will reduce the friction and thus will help in maintaining the efficiency of the VCR gear in the internal combustion engine 100.
[00017] In light of the above mentioned advantages and the technical advancements provided by the disclosed method and system, the claimed steps as discussed above are not routine, conventional, or well understood in the art, as the claimed steps enable the following solutions to the existing problems in conventional technologies. Further, the claimed steps clearly bring an improvement in the functioning of the device itself as the claimed steps provide a technical solution to a technical problem.
[00018] While the present disclosure has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from its scope. Therefore, it is intended that the present disclosure may not be limited to the particular embodiment disclosed, but that the present disclosure will include all embodiments falling within the scope of the appended claims.
, Claims:We claim:
1. An internal combustion engine (100) comprising:
a crankcase (108);
a crankshaft (104), said crankshaft (104) being supported by said crankcase (108) and said crankshaft (104) being rotatable about a crankshaft axis (112);
one or more connecting rod (114), said one or more connecting rod (114) includes a first end and a second end; and
a piston (116), said piston (116) being rotatably connected to said first end of said one or more connecting rod (114);
wherein,
one or more gear members (118) being disposed on said crankshaft (104), and said one or more gear members (118) being connected in a transmission path forming a variable compression ratio system;
wherein, an oil path (126) being provided in said crankshaft (104), said oil path (126) being provided with a forced spray mechanism configured to lubricate said one or more gears (118) of said variable compression ratio system.

2. The internal combustion engine (100) as claimed in claim 1, wherein said one or more gears (118) include a first gear (120), a second gear (122), and a third gear (124), said first gear (120), said second gear (122), and said third gear (124) being connected in said transmission path forming said variable compression ratio system.
3. The internal combustion engine (100) as claimed in claim 2, wherein said first gear (120) being disposed between a connecting rod (114) of said piston (116) and a crank pin (110), wherein said crank pin (110) being supported by said crankshaft (104).
4. The internal combustion engine (100) as claimed in claim 2, wherein said second gear (122) and said third gear (124) being supported by said crankshaft (104), said first gear (120) and said second gear (122) being configured to mesh with said third gear (124).
5. The internal combustion engine (100) as claimed in claim 2, wherein said first gear (120) being an eccentric gear.
6. The internal combustion engine (100) as claimed in claim 2, wherein said second gear (122) being a VCR (Variable Compression Ratio) gear.
7. The internal combustion engine (100) as claimed in claim 2, wherein said third gear (124) includes a first intermediate gear (124a) and a second intermediate gear (124b).
8. The internal combustion engine (100) as claimed in claim 1, wherein said oil path (126) includes a first path (126a), a second path (126b), and a third path (126c),
wherein said first path (126a) being configured to receive oil for lubrication from a pump system.
9. The internal combustion engine (100) as claimed in claim 8, wherein said second path (126b) and said third path (126c) being configured to receive oil coming from said first path (126a),
wherein oil in said second path (126b) lubricates a bearing (106) of said crank pin (110) of said crankshaft (104).
10. The internal combustion engine (100) as claimed in claim 9, wherein oil in said third path (126c) being configured to lubricate said one or more gears (118) of said variable compression ratio system.
11. The internal combustion engine (100) as claimed in claim 8, wherein said third path (126c) includes a first end and a second end, said first end of said third path (126c) being connected to said first path (126a) through an oil path extension (128),
wherein said second end being provided with an oil jet nozzle (130) to facilitate forced lubrication of said one or more gears (118) of said variable compression ratio system.
12. The internal combustion engine (100) as claimed in claim 7 and claim 11, wherein, said third path (126c) being provided with said oil jet nozzle (130) configured to direct oil towards said first intermediate gear (124a) of said third gear (124),
wherein, said first intermediate gear (124a) includes one or more openings (132), said one or more openings (132) allows oil to reach an interface between said second gear (122) and said second intermediate gear (124b).
13. The internal combustion engine (100) as claimed in claim 11, wherein, said third path (126c) being provided with said oil jet nozzle (130) to facilitate forced lubrication by means of splashed lubrication of said one or more gears (118) of said variable compression ratio system.
14. The internal combustion engine (100) as claimed in claim 1, wherein said oil path (126) being provided on one of a left side crankshaft (104a) or a right side crankshaft (104b) of said internal combustion engine (100).
15. The internal combustion engine (100) as claimed in claim 1, wherein said first path (126a) of said oil path (126) being configured to have a first width and said third path (126c) of said oil path (126) being configured to have a second width,
wherein said first width being greater than said second width.