Description:FORM 2

THE PATENTS ACT, 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[SEE SECTION 10, RULE 13]

AN OIL COOLER SYSTEM FOR AN ENGINE

MAHINDRA & MAHINDRA LIMITED, A COMPANY REGISTERED UNDER THE INDIAN COMPANIES ACT, 1913, HAVING ADDRESS AT MAHINDRA RESEARCH VALLEY, MAHINDRA WORLD CITY, PLOT NO: 41/1, P.O. – ANJUR, CHENGALPATTU – 603004, TAMIL NADU, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

TECHNICAL FIELD
[001] The present invention relates to an oil cooler system for an engine like a farm vehicle engine with a reduced size of an oil cooler and increased heat dissipation of engine oil and engine coolant for maintaining a desired film thickness of the engine oil.

BACKGROUND
[002] Generally, it is known that an engine oil temperature or the engine lubricating oil temperature is proportional to an increase in power of the engine or use of turbo chargers or piston cooling jet for the engine. It is desired to maintain a desired film thickness of the engine oil at moving parts for example in bearings. However, it is also known that film thickness of the engine oil is proportional to temperature of the engine oil and as the temperature of the engine oil increases with proportional increase of engine power, the film thickness of the engine oil is reduced. The reduced film thickness of the engine oil leads to metal-to-metal contact of dynamic components of the engine resulting in wear of engine components and engine seizure or reduced engine life.
[003] Hence, to safeguard the dynamic components of engine or reduce the wear of engine components, referring to Figure 1, conventionally, it is known to provide an oil cooler (110) for the engine (100). The oil cooler (110) is mounted on an engine block (105). An oil lubrication filter (120) is provided at the bottom of the oil cooler (110). An engine coolant inlet pipe (115a) and an engine coolant out pipe (115b) are coupled to the oil cooler (110) for supplying engine coolant that reduces the temperature of the engine oil. Further, the engine (100) is provided with a fan (125) to provide air circulation for cooling the temperature of the engine coolant. The oil cooler (110) is provided with a plurality of staggered oil cooler plates that determine the efficiency of the oil cooler (110). The oil cooler (110) is mainly used to reduce/limit the engine oil temperature crossing beyond certain limit i.e., 130°C for retaining the minimum oil film thickness at a journal bearing surface. Engine oil cooling is required to reduce heat generated from the engine (100) such that film thickness of the engine oil is maintained and lubrication at the rotating joints is improved.
[004] However, as the power of the engine (100) increase, the heat rejections of the engine (100) increases and therefore, oil cooler (110) of a larger size is required to maintain / reduce the engine oil temperature or increase the efficiency of cooling the engine oil. The increased size of the oil cooler increases cost of the oil cooler, design modifications to the engine, and the number of staggered oil cooler plates increases size/envelope of the engine. Another limitation of increased oil cooler (110) size is that the quantity of the engine coolant required to be passed into the oil cooler (110) also increases.
[005] Therefore, there is a need to provide an oil cooler system to overcome one or more of the aforementioned problems.

SUMMARY
[006] Accordingly, an exemplary aspect of the present invention discloses a primary cooling circuit located within said engine block for a first cooling stage of said engine oil, said primary cooling circuit having an engine coolant inlet guideway and an engine coolant outlet guideway for passing an engine coolant for cooling an engine oil; an oil lubrication filter having an oil filter header for receiving primary cooled oil from said first cooling stage within the engine block, said oil lubrication filter having a secondary cooling circuit for a second cooling stage of said engine oil along with filtration of the engine oil; and an oil cooler having a third cooling circuit as a third cooling stage of said engine oil, said oil cooler further cools said filtered and cooled engine oil received from second cooling stage by the engine coolant received from said primary cooling circuit.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[007] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:
[008] Figure 1 illustrates an isometric view of a conventional oil cooler for an engine;
[009] Figure 2 illustrates an isometric view of an oil cooler system for an engine, according to an exemplary aspect of the present invention;
[010] Figure 3 illustrates a detailed isometric view of an oil cooler with a plurality of fins on at least a surface of the oil cooler, according to an embodiment of the present invention;
[011] Figure 4 illustrates a detailed isometric view of the oil cooler system with multi-stage cooling circuits, according to the embodiment of the present invention;
[012] Figure 5 illustrates a detailed cross-sectional side view of the oil cooler system showing the multi-stage cooling circuits and oil cooler, according to the embodiment of the present invention;
[013] Figure 6A and Figure 6B illustrates a detailed cross-sectional side view of the oil cooler system showing a primary cooling circuit with coolant and oil guideways, according to the embodiment of the present invention;
[014] Figure 7 illustrates a graph showing engine oil temperature comparison between conventional oil cooler and oil cooler system of the present invention; and
[015] Figure 8 illustrates an isometric view of the oil cooler system, according to another exemplary embodiment of the present invention.
[016] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to the other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference signs are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION
[017] While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail, a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspects of the invention to the embodiment illustrated.
[018] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. Embodiments of the present disclosure will now be described with reference to the accompanying drawings. Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to a person skilled in the art. Numerous details are set forth relating to specific components to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
[019] In general, the present invention claims, an oil cooler system for an engine comprising an engine block having at least a primary cooling circuit, an oil lubrication filter having an oil filter header with a secondary cooling circuit and an oil cooler having a third cooling circuit and an oil cooler header said oil cooler system with said cooling circuits enables reducing a size of said oil cooler and increasing a heat dissipation of engine oil and engine coolant, thereby maintaining a film thickness of the engine oil.
[020] According to an exemplary aspect, the present invention discloses an oil cooler system for an engine like a farm vehicle engine. The oil cooler system includes an engine block with plurality of coolant pipes, an oil cooler, an oil lubrication filter, and a fan. To reduce the temperature of oil, an engine coolant/water has been used as medium of fluid and is made to pass to the oil cooler. It is known that engine coolant temperatures are always lesser than engine oil temperatures. The engine coolant is extracted from the engine and is provided to the engine oil cooler system (forced cooling system). The engine coolant is pumped by a separate cooling pump and a portion of the cooling is taken into the oil cooler. The oil cooler is mounted on a side face or front face of the engine block as per design of the engine. The oil cooler includes an oil cooler header with a plurality of circumferential heat transfer fins in addition to the coolant which are integrated in mounting adapter / oil filter header and cooler to accelerate heat transfer rate. The circumferential heat transfer fins reduce the temperature of both oil and coolant which also reduces heat load on a radiator. This arrangement will enhance the cooling in both oil and coolant by using engine coolant and forced air from a cooling fan. The oil lubrication filter is located at bottom of the oil cooler. The oil lubrication filter includes an oil filter header. The cooling fan is mounted on front face of the engine block lateral to the oil cooler. The cooling fan pushes forced air towards the engine that provides forced air circulation to the engine that in turn reduces the temperature of the engine.
[021] According to an exemplary embodiment, the engine block has a primary cooling circuit located within said engine block. Before the engine oil enters to cooler from crank case, there is supplementary cooling jacket provided inside the cylinder block for the oil temperature reduction. In the primary cooling circuit heat rejection takes by using engine coolant. The primary cooling circuit has at least an engine coolant guideway for passing an engine coolant in a clockwise flow direction for cooling engine oil at a first cooling stage of engine oil within the engine block. The primary cooling circuit has at least an oil guideway parallel to the engine coolant guideway for passing oil in counterclockwise flow direction with the engine block.
[022] According to the exemplary embodiment, a first stage cooled engine oil is then made to pass into the oil lubrication filter via the oil filter header. The oil filter header / adaptor is provided with a secondary cooling circuit. After entering oil to the filter, a plurality of heat transfer fins are provided on periphery of oil cooler and cast aluminum mounting adapter / oil filter header to further cool and provide heat transfer to oil and coolant. The secondary cooling circuit reduces the oil temperature by forced air coming from the engine cooling fan and thus increases the forced convection heat transfer. The secondary cooling circuit includes a plurality of first set of fins located externally on at least a surface of the oil filter header for providing a second cooling stage of engine oil. The provision of fins on surface of the oil filter header aid in natural convection or forced heat transfer cooling of the engine oil temperature and act as a first additional heat sink.
[023] According to the exemplary embodiment, the second stage cooled oil is then made to pass into the oil cooler for a higher level of heat rejection. The oil cooler is of a donut shaped cooler with a plurality of circumferential heat transfer fins. The oil cooler is mounted on a side face of said engine block. Referring Figure 8 illustrates another embodiment of the present invention, wherein the oil cooler of the present invention is located on a front face of said engine block in front of engine fan on front cover to improve the cooling efficiency based on the engine architecture for trapping the oil and coolant similar to side way mounting on engine block. The oil lubrication filter is located at a bottom of said oil cooler. The oil cooler is also provided with a third cooling circuit. Finally, the filtered oil goes to the main oil cooler of the third or main cooling circuit, where high level of heat rejection occurs due to oil cooler plate arrangements in staggered manner. Based on oil temperature, no of plates required for the engine is derived. The third cooling circuit includes a plurality of oil cooler plate arrangement and as well as engine coolant flow located within the oil cooler that act as a second additional heat sink. The oil cooler is provided internally with at least 10 to 18 numbers of longitudinal oil cooler plates arrangement with various power ratings. The third cooling circuit further includes a plurality of second set of fins located circumferentially and externally on at least a surface of the oil cooler body and oil cooler header for providing a third cooling stage of engine oil and engine coolant and to increase the heat dissipation from the engine coolant and engine oil, thereby maintaining the desired film thickness of the engine oil and increasing the efficiency of engine oil cooling. Ambient air is passed therethrough the oil filter header and oil cooler both provided with a plurality of first and second set of fins, for reducing the temperature of engine oil naturally or by forced air circulation.
[024] According to the exemplary embodiment, with the introduction of multi-stage cooling circuits to reduce engine oil temperature, it is made possible to reduce the number of oil cooler plates arrangement within the oil cooler, thereby decreasing the size of the oil cooler by reducing the load on the oil cooler. Also, the quantity of engine coolant required to cool the engine oil is also reduced. Heat rejection / dissipation area of the oil cooler system is increased, and heat is dissipated from the engine coolant as well as the engine oil. Fan is provided as an additional measure so that efficiency of dissipating the heat from oil and engine coolant is increased in such a way that higher heat dissipation is achieved by lower sized oil cooler.
[025] According to the exemplary embodiment, with the teachings of the present invention oil temperature is reduced by 10-15 ºC when compared with conventional oil cooler. Further, with the teachings of the present invention number of plates within the oil cooler have reduced, thereby by reducing envelope size of oil cooler. The complete oil cooler system of the present invention is assembled in front of engine cooling fan to maximize the heat transfer rate. The complete oil cooler system of the present invention may be assembled in front of engine on front face cover to maximize the heat transfer rate. All primary and secondary cooling arrangements are possible in front face cover as well based on engine architecture.
[026] The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results. As used in the present disclosure, the forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises,” “comprising,” “including,” “made of” and “having,” are open ended transitional phrases and therefore specify the presence of stated elements, units and/or components, but do not forbid the presence or addition of one or more other elements, components, and/or groups thereof.
[027] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. Accordingly, it should be apparent to those skilled in the art that the following description of oil cooler system referred in the description are for the purpose of understanding and nowhere limit the invention. The skilled person will be able to devise various structures, shapes of the oil cooler system that, although not explicitly described herein, embody the principles of the present invention. All the terms and expressions in the description are only for the purpose of the understanding and nowhere limit the invention. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein may be made without departing from the scope of the invention. Terms like plurality, top, bottom, front face, side face, first, second, parallel, inner, outer, internal, external, primary, secondary, third and the like are used to differentiate between objects having the same terminology and are in no way intended to represent a chronological order, unless where explicitly stated otherwise. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof. Thus, while particular type of structure the oil cooler system, oil header, oil cooler, guideways, fins, coolant configuration with desired volume, depth, shape, material, heights, lengths, widths, diameters, thickness, distances, angles, inclination, quantity, numbers, have been disclosed, nowhere limit the invention and are provided for understanding of the invention. It will be appreciated that the embodiments may be manufactured with other design parameters and configurations as well and are not limited to those described herein above may be as per operational requirements by making necessary changes and is not limited to those described herein and nowhere limits the scope of the invention and are provided only for reference and for understating purpose of the invention.
[028] Figures 2-8 disclose an oil cooler system (200), an engine block (205), an oil lubrication filter (210), an oil filter header (215), an oil cooler (220), a primary cooling circuit (230), an engine coolant inlet guideway (232), an engine coolant outlet guideway (234), a first cooling stage (235), an engine oil inlet guideway (236), an engine oil outlet guideway (238), a secondary cooling circuit (240), a second cooling stage (245), a third cooling circuit (250), a third cooling stage (255), an engine coolant inlet pipe (252), an engine coolant outlet pipe (254), a plurality of longitudinal oil cooler plates (256), a plurality of first set of fins (260), a plurality of second set of fins (270) and a fan (280).
[029] According to an exemplary aspect, the present invention, Figures 2-8, disclose an oil cooler system (200) for an engine, the engine includes an engine block (205), the oil cooler system (200) comprises: at least a primary cooling circuit (230) with at least an engine coolant inlet guideway (232) and at least an engine coolant outlet guideway (234) for regulating/passing an engine coolant in a clockwise flow direction for cooling an engine oil, the primary cooling circuit (230) located within the engine block (205) for a first cooling stage (235) of the engine oil. The oil cooler system (200) includes an oil lubrication filter (210) having an oil filter header (215) with a secondary cooling circuit (240) for a second cooling stage (245) of the engine oil along with filtration of the engine oil. The oil lubrication filter (210) receives primary cooled oil from said first cooling stage (235) within the engine block (205). The oil cooler system (200) includes an oil cooler (220) having a third cooling circuit (250) and an oil cooler header as a third cooling stage (255) of the engine oil, the oil cooler system (200) further cools said filtered and cooled engine oil received from second cooling stage (245) by the engine coolant received from said primary cooling circuit (230). The oil cooler system (200) with the multi-stage cooling circuits (230, 240, 250) enables reducing a size of the oil cooler (220) and increasing a heat dissipation of the engine oil and the engine coolant, thereby maintaining a film thickness of the engine oil.
[030] According to an exemplary embodiment, the oil cooler (220) is a donut shaped oil cooler and the primary cooling circuit (230) with the engine coolant guideways (232, 234), the engine oil inlet guideway (236) and the engine oil outlet guideway (238) are horse-shoe shaped circuit. The oil cooler system (200) includes an oil cooler (220) mounted on a side face or on a side face of the engine block (205) and the oil lubrication filter (210) located at a bottom of the oil cooler (220).
[031] According to the exemplary embodiment, the primary cooling circuit (230) has at least the engine oil inlet guideway (236) and the engine oil outlet guideway (238) parallel to the engine coolant guideways (232, 234) for passing the engine oil in a counterclockwise flow direction to the flow of engine coolant within the engine block (205). The secondary cooling circuit (240) includes a first additional heat sink having a plurality of first set of fins (260) located circumferentially and externally on at least a surface of the oil filter header body (215) for enabling the second cooling stage (245) of said engine oil by natural convection. The heat transfer fin’s accelerate cooling when oil interacts on the oil filter header body (215). The third cooling circuit (250) includes a plurality of longitudinal oil cooler plates (256) located internally within the said oil cooler (220) as a second additional heat sink. The third cooling circuit (250) includes the engine coolant inlet pipe (252) and the engine coolant outlet pipe (254) coupled to the oil cooler (220) to the plurality of longitudinal oil cooler plates (256) for supplying engine coolant that reduces the temperature of engine oil. The third cooling circuit (250) includes a plurality of second set of fins (270) located circumferentially and externally on at least a surface of the oil cooler (220) body and oil cooler header for enabling the third cooling stage (255) of engine oil and said engine coolant.
[032] According to the exemplary embodiment, the oil cooler system (200) includes a cooling fan (280) mounted on front face of the engine block (205) lateral to the oil cooler (220) for pushing forced air circulation towards the engine for reducing temperature of the engine coolant and engine oil. In the present invention, a separate cooling pump located within said engine regulates a desired said engine coolant/water in a reduced extracted quantity from the engine into said oil cooler system (200) for reducing the temperature of engine oil at the first cooling stage (235).
[033] According to the exemplary embodiment, Figure 7 illustrates a graph showing engine oil temperature between conventional oil cooler system - A and oil cooer system (200) – B of the present invention. Line – A represents conventional oil cooler arrangement with a single heat transfer element, wherein the engine oil temperature is recorded at temperature 126-129 °C approximately, close to limit of 130 °C after which oil film thickness may not be retained. Whereas Line – B represent the oil cooler system (200) of the present invention, wherein the engine oil temperature is recorded at temperature 111-114 °C approximately, farther away from the limit of 130 °C. With the teachings various cooling circuits of the present invention oil temperature is reduced by 10-15 ºC approximately when compared with conventional oil cooler. Therefore, oil film thickness is comfortably retained with the enhanced oil cooling provided in the present invention. Further, with the teachings of the present invention number of plates within the oil cooler have reduced, thereby by reducing envelope size of oil cooler. The complete oil cooler system of the present invention is assembled in front of engine cooling fan to maximize the heat transfer rate.
[034] There have been described and illustrated herein several embodiments of exemplary indicative implementation of an oil cooler system for an engine. It will also be apparent to a skilled person that the embodiments described above are specific examples of a single broader invention, which may have greater scope than any of the singular descriptions taught. There may be many alterations made in the description without departing from the scope of the invention. The present invention is simple in construction and design, integrated, cost effective and easy to manufacture and assemble. While particular embodiments of the invention have been described, it is not intended that the invention be limited to said configuration disclosed thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise not restrictive to the terminology described herein above. Any discussion of embodiments included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
 
, Claims:We Claim:

1. An oil cooler system (200) for an engine, said engine includes an engine block (205), said oil cooler system (200) comprising:
a primary cooling circuit (230) located within said engine block (205) for a first cooling stage (235) of said engine oil, said primary cooling circuit (230) having an engine coolant inlet guideway (232) and an engine coolant outlet guideway (234) for passing an engine coolant for cooling an engine oil;
an oil lubrication filter (210) having an oil filter header (215) for receiving primary cooled oil from said first cooling stage (235) within the engine block (205), said oil lubrication filter (210) having a secondary cooling circuit (240) for a second cooling stage (245) of said engine oil along with filtration of the engine oil; and
an oil cooler (220) having a third cooling circuit (250) as a third cooling stage (255) of said engine oil, said oil cooler (220) further cools said filtered and cooled engine oil received from second cooling stage (245) by the engine coolant received from said primary cooling circuit (230).

2. The oil cooler system (200) as claimed in claim 1, said oil cooler (220) is a donut shaped oil cooler and said oil cooler (220) is mounted on a side face of said engine block (205) or on a front face of said engine block (205) and said oil lubrication filter (210) is located at a bottom of said oil cooler (220).

3. The oil cooler system (200) as claimed in claim 1 or 2, wherein said primary cooling circuit (230) has at least an engine oil inlet guideway (236) and an engine oil outlet guideway (238) parallel to the engine coolant guideways (232, 234) for passing engine oil in a counterclockwise flow direction to said flow of engine coolant in a clockwise coolant flow direction within said engine block (205).

4. The oil cooler system (200) as claimed in anyone of preceding claims 1-3, wherein said primary cooling circuit (230) with said engine coolant guideways (232, 234) and engine oil inlet, outlet guideways (236, 238) is horse-shoe shaped circuit.

5. The oil cooler system (200) as claimed in anyone of preceding claims 1-4, wherein said secondary cooling circuit (240) includes a first additional heat sink having a plurality of first set of fins (260) located circumferentially and externally on at least a surface of said oil filter header (215) for enabling said second cooling stage (245) of said engine oil by natural convection or forced convection.

6. The oil cooler system (200) as claimed in anyone of preceding claims 1-5, wherein said third cooling circuit (250) includes a plurality of longitudinal oil cooler plates (256) located internally within the said oil cooler (220) as a second additional heat sink.

7. The oil cooler system (200) as claimed in anyone of preceding claims 1-6, wherein said third cooling circuit (250) includes a set of engine coolant inlet pipe (252) and an engine coolant outlet pipe (254) coupled to said oil cooler (220) to said plurality of longitudinal oil cooler plates (256) for supplying engine coolant from said primary cooling circuit (230) that reduces the temperature of engine oil.

8. The oil cooler system (200) as claimed in anyone of preceding claims 1-7, wherein said third cooling circuit (250) includes a plurality of second set of fins (270) located circumferentially and externally on at least a surface of the oil cooler (220) body and oil cooler header in addition to coolant for enabling said third cooling stage (255) of engine oil and said engine coolant.

9. The oil cooler system (200) as claimed in anyone of preceding claims 1-8, wherein said oil cooler system (200) includes a cooling fan (280) mounted on front face of said engine block (205) lateral to the oil cooler (220) for pushing forced air circulation towards the engine for reducing temperature of the engine coolant and engine oil.

10. The oil cooler system (200) as claimed in anyone of preceding claims 1-9, wherein a separate cooling pump located within said engine regulates a desired said engine coolant/water in a reduced extracted quantity from the engine into said oil cooler system (200) for reducing the temperature of engine oil at said first cooling stage (235).

Dated this 27th day of March, 2023
FOR MAHINDRA & MAHINDRA LIMITED
By their Agent

(GIRISH VIJAYANAND SHETH) (IN/PA 1022)
KRISHNA & SAURASTRI ASSOCIATES LLP