Description:Field of Invention
[001] The invention relates to internal combustion engines running on gaseous fuels. It more particularly relates to pistons provided in internal combustions engines running on gaseous fuels that have been provided with specific features to reduce engine oil burning. It additionally relates to piston provided in internal combustion engines running on gaseous fuels that have been provided with specific features to ensure proper cooling of the provided piston using flowing liquid such as lubricating oil.
Background of the Invention
[002] Typical pistons utilised in internal combustion engines running on gaseous fuels are known to burn engine oils far in excess of comparable pistons provided in internal combustion engines running on liquid fuels. This happens because the features that suffice to provide a sufficient thickness of lubricating oil film between the sleeve and the piston’s outer wall in case of internal combustion engines running on liquid fuels end up dragging with itself a far greater quantity of oil than is necessary for lubricating the walls of the piston in engines running on gaseous fuels. Therefore, engines running on gaseous fuels eventually end up burning a greater proportion of engine oil than their liquid fuel-burning counterpart, internal combustion engines.
[003] Additionally, typical pistons as provided in internal combustion engines running on gaseous fuels, are also not provided with any features that can circulate liquid lubricating oil within the body of the piston to sufficiently cool it while the engine is running. This may cause such a piston to deform under the heat generated during combustion and scratch and deform the cylindrical sleeve provided between the engine block and the piston. The existing features may also find it hard to balance heat removal from the piston, thereby, in some instances, removing far greater heat than necessary, thereby leading to wastage of energy that may otherwise have been utilised to perform useful work. Therefore, it is an objective of the present invention to provide a piston for internal combustion engines running on gaseous fuels that ensures on required lubrication of the piston and heat removal from the piston during the running of the internal combustion engine.
[004] It is another objective of the present invention to provide features that enhance the life of the piston by ensuring that it does not get damaged due to inadequate lubrication.
[005] It is still another objective of the present invention to provide features that ensure that the piston is cooled by a circulating liquid lubricant only as much as is required for the proper running of the engine.
[006] It is yet another objective of the present invention to provide a piston with features that ensure it does not burn too much lubrication oil while the internal combustion engine running on gaseous fuels is operating.
Summary of the Invention
[007] An embodiment of the invention achieving the stated objective that is a piston for an engine running on LNG/PNG (100), having a piston assembly that comprises of circlips (5, 45), a piston (10), a piston pin (15), a connecting rod (20), screws (25), compression rings (30, 35), an oil scrapping ring (40), a conrod end bush (50), and conrod end bearings (55, 60). In the piston for an engine running on CNG/LNG, the piston (10) is provided with three grooves one above the other in a top portion of its cylindrical body that accommodate proceeding from top to bottom, compression rings (30, 35) and an oil scrapper ring (40), the piston (10) is additionally provided with a deep grove (10G1) on the outer wall of the piston (10) between the compression rings (30, 35) and a shallow grove (10G2) on the outer wall of the piston (10) between compression ring (35) and oil scrapper ring (40) respectively; an opening given in the lower portion of the piston (10) that accommodates a piston pin (15) that is held within said opening utilising circlips (5, 45) as provided on either end of said piston pin (15); an opening at the upper end of the connecting rod (20) accommodates the conrod end bush (50) via which said connecting rod (20) is linked with the piston pin (15); the upper end of the connecting rod (20) has an opening (20H) that leads to the opening accommodating said conrod end bush (50) so as to allow lubricating fluid to flow towards said conrod end bush (50); and an opening at the lower end of the connecting rod (20) accommodates conrod end bearings (55, 60); the lower end of the connecting rod (20) is made in two portions that are connected together using the screws (25).
Brief Description of Drawings
[008] The present invention is illustrated in the accompanying drawings that contain references numerals for indicating its various parts. The description of the present invention would therefore be better understood with reference to accompanying diagrams, wherein
[009] Figure 1 discloses the side view of the fully assembled piston assembly with the piston as per preferred embodiment of the present invention.
[0010] Figure 2 discloses an exploded view of the piston assembly with the piston as per the preferred embodiment of the present invention.
[0011] Figure 3 discloses the cut section and a magnified portion of the cut section of the piston as per the preferred embodiment of the present invention.
[0012] Figure 4 discloses the top view of the piston as per the preferred embodiment of the present invention.
[0013] Figure 5 discloses the bottom view of the piston as per preferred embodiments of the present invention.
Detailed Description of the Invention
[0014] Referring to the set of figures 1, and 2, the piston for an engine running on CNG/LNG (Compressed Natural gas/Liquified Natural Gas) (100), as provided in piston assembly that comprises of, circlips (5, 45), a piston (10), a piston pin (15), a connecting rod (20), screws (25), compression rings (30, 35), an oil scrapping ring (40), a conrod end bush (50), and conrod end bearings (55, 60). The piston for an engine running on CNG/LNG (Compressed Natural gas/Liquified Natural Gas) (100) is as shown in the figures and as described hereinafter.
[0015] Referring to figures 1 and 2, it is stated that, the piston (10) is provided with three grooves one above the other in a top portion of its cylindrical body that accommodate proceeding from top to bottom, compression rings (30, 35) and an oil scrapper ring (40), the piston (10) is additionally provided with a deep grove (10G1) on the outer wall of the piston (10) between the compression rings (30, 35) and a shallow grove (10G2) on the outer wall of the piston (10) between compression ring (35) and oil scrapper ring (40) respectively. Given this construction, the lubricating oil is only able to form a very thin and limited protection film between the piston and the cylinder lining. This, therefore, limits the lubricating oil that eventually reaches the combustion chamber during the working of the internal combustion engine provided with the invention as described. The compression rings work to reduce the blow-by of gases when the internal combustion engine is operating.
[0016] Referring to figures 1 and 2, it is stated that, an opening given in the lower portion of the piston (10) that accommodates a piston pin (15) that is held within said opening utilising circlips (5, 45) as provided on either end of said piston pin (15). An opening at the upper end of the connecting rod (20) accommodates the conrod end bush (50), via which said connecting rod (20) is linked with the piston pin (15). The upper end of the connecting rod (20) has an opening (20H) that leads to the opening accommodating said conrod end bush (50) so as to allow lubricating fluid to flow towards said conrod end bush (50). This ensures that said bush (50) gets adequate lubrication from the lubricating oil coming down from the piston (10).
[0017] Again referring to Figures 1 and 2, it is stated that, an opening at the lower end of the connecting rod (20) accommodates conrod end bearings (55, 60). These bushes limit the frictional losses happening during power transmission from the connecting rod to the crankshaft. The lower end of the connecting rod (20) is made in two portions that are connected together using the screws (25). The piston (10) (refer to Figs 3 and 5) is provided with an annular chamber (10AC) in the top portion of the piston that has a cross-section roughly resembling a trapezoid that has been provided with curved upper and lower side. The annular chamber (10AC) is provided with openings (10H1, and 10H2) that are separated from each other by an angle of 180 degrees. These openings (10H1, 10H2) allow oil that has been shot up from below by the lubricating oil sprayer to enter and leave the piston after having removed excess heat from the piston (10)’s body.
[0018] Referring to Figures 2 and 5, it is stated that the annular chamber (10AC) is provided with another opening (10H3) that is located between the openings (10H1, 10H2) along the circular periphery of the annular chamber (10AC) on the piston (10). The opening (10H1) is smaller than either of the openings (10H1, 10H2). The opening (10H3) as provided on the annular chamber (10AC) in the piston (10) is configured to align with the openings (20H) given on the upper portion of the connecting rod (20) when the piston (10) reciprocates within the chamber of the internal combustion engine. The oil leaving the piston (10)’s body through the opening (10H3) therefore tends to flow into the opening (20H) given in the connecting rod (20).
[0019] The piston (10) (referring to Figures 3, and 4) has a crown that is configured to have an outer ring (10R1) that is at a greater height than a depressed central portion. The depressed central portion is in turn configured to have a circular frusto-conical central portion (10CR) in its centre. The circular frusto-conical central portion (10CR) has a greater height than its surrounding depressed central portion but not the outer ring (10R1). These features of the piston (10) help facilitate proper combustion of the gaseous fuel when the internal combustion engine is operating.
[0020] The piston for an engine running on CNG/LNG (100) has been specifically configured to run in internal combustion engines that burn gaseous fuels. It does the same while ensuring the best fuel-possible fuel efficiency, minimum lubrication oil burn and effective cooling of the piston.
[0021] Technical advantages offered by the invention i.e., the piston for an engine running on CNG/LNG (Compressed Natural gas/Liquified Natural Gas) (100) are-
- It ensures that the piston receives only the required lubrication and heat removal during the running of the internal combustion engine running on gaseous fuels.
- It enhances the life of pistons being used in internal combustion engines running on gaseous fuels.
- It ensures that the piston is cooled by a circulating liquid lubricant only as much as is required for the proper running of the engine.
- It reduces the burning of lubrication oil in internal combustion engines running on gaseous fuels.
[0022] The disclosed invention i.e. the piston for an engine running on CNG/LNG (Compressed Natural gas/Liquified Natural Gas) (100) achieves all the set-out objectives.
[0023] It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the present invention has been herein described in terms of its preferred embodiment, those skilled in the art will recognize that the preferred embodiment herein disclosed, can be practiced with modifications within the scope of the invention herein described.
, Claims:We Claim,
1. A piston for an engine running on CNG/LNG (100) in a piston assembly comprising,
• circlips (5, 45),
• a piston (10),
• a piston pin (15),
• a connecting rod (20),
• screws (25),
• compression rings (30, 35),
• an oil scrapping ring (40),
• a conrod end bush (50),
• conrod end bearings (55, 60),
wherein,
- the piston (10) is provided with three grooves one above the other in a top portion of its cylindrical body that accommodate proceeding from top to bottom, compression rings (30, 35) and an oil scrapper ring (40), the piston (10) is additionally provided with a deep grove (10G1) on the outer wall of the piston (10) between the compression rings (30, 35) and a shallow grove (10G2) on the outer wall of the piston (10) between compression ring (35) and oil scrapper ring (40) respectively;
- an opening given in the lower portion of the piston (10) that accommodates a piston pin (15) that is held within said opening utilising circlips (5, 45) as provided on either end of said piston pin (15);
- an opening at the upper end of the connecting rod (20) accommodates the conrod end bush (50) via which said connecting rod (20) is linked with the piston pin (15); the upper end of the connecting rod (20) has an opening (20H) that leads to the opening accommodating said conrod end bush (50) so as to allow lubricating fluid to flow towards said conrod end bush (50); and
- an opening at the lower end of the connecting rod (20) accommodates conrod end bearings (55, 60); the lower end of the connecting rod (20) is made in two portions that are connected together using the screws (25).
2. The piston for an engine running on CNG/LNG (100) as claimed in claim 1, wherein, the piston (10) is provided with an annular chamber (10AC) in the top portion of the piston that has a cross-section roughly resembling a trapezoid that has been provided with curved upper and lower side.
3. The piston for an engine running on CNG/LNG (100) as claimed in claim 2, wherein, the annular chamber (10AC) is provided with openings (10H1, and 10H2) that are separated from each other by an angle of 180 degrees.
4. The piston for an engine running on CNG/LNG (100) as claimed in claim 3, wherein,
- the annular chamber (10AC) is provided with another opening (10H3) that is located between the openings (10H1, 10H2) along the circular periphery of the annular chamber (10AC) on the piston (10); and
- the opening (10H1) is smaller than either of the openings (10H1, 10H2).
5. The piston for an engine running on CNG/LNG (100) as claimed in claim 4, wherein, the opening (10H3) as provided on the annular chamber (10AC) in the piston (10) is configured to align with the openings (20H) given on the upper portion of the connecting rod (20) when the piston (10) reciprocates within the chamber of the internal combustion engine.
6. The piston for an engine running on CNG/LNG (100) as claimed in claim 5, wherein,
- the piston (10), has a crown that is configured to have an outer ring (10R1) that is at a greater height than a depressed central portion;
- where the depressed central portion is in turn configured to have a circular frusto-conical central portion (10CR) in its centre; and
- with the circular frusto-conical central portion (10CR) having a greater height than its surrounding depressed central portion but not the outer ring (10R1).
Dated 25th day of February 2025

VIDIT CHOUBEY
(IN P/A 5566)
AGENT FOR THE APPLICANT(S)

To,
The Controller of Patents,
The Patent Office, at Mumbai