WO2018178836A1

WO2018178836A1 - Oil cooler for an internal combustion engine

Info

Publication number: WO2018178836A1
Application number: PCT/IB2018/052019
Authority: WO
Inventors: Nagendra Kumar Dharmapuri; Pillai Loganayakan PADMANABHA; Vijay Kumar RAJENDRAN; Iyengar Lakshminarasimhan VARADHA
Original assignee: Tvs Motor Company Limited
Priority date: 2017-03-28
Filing date: 2018-03-26
Publication date: 2018-10-04
Also published as: BR112019020408A2; EP3601760A1; MX2019011551A; PE20191561A1

Abstract

The present subject matter discloses an internal combustion (IC) engine (101). The internal combustion (IC) engine (101) comprising a heat exchanger (201). The heat exchanger (201) is integrated to a cylinder block (204) on a return path of engine oil after cooling a combustion chamber (207) and is thermally isolated from the cylinder block (204) through an air gap (401). Further, the circuitous path of oil flow within the heat exchanger (201) is designed based on cooling efficiency and IC engine design requirements. Furthermore, the integrated heat exchanger (201) comprises perpendicular projections (206b, 501a) around its outer surface to further improve the rate of dissipation of heat. The present subject matter eliminates the need for external heat exchanger, provides better cooling and lubricating characteristics of engine oil. Ultimately, the performance of the IC engine (101) also improves through optimization of available space.

Description

OIL COOLER FOR AN INTERNAL COMBUSTION

ENGINE

FIELD OF INVENTION

[0001] The present subject matter relates generally to an internal combustion engine for a saddle type vehicle. More particularly, the present subject matter relates to an integrated oil cooler used for cooling engine oil on the internal combustion engine.

BACKGROUND

[0002] During operation of the IC engine, the burning of fuel and air occurs inside an internal combustion (IC) engine generating mechanical energy which provides motive force for movement of a saddle type, for example a two wheeled vehicle. But, this operation generates lot of thermal energy on and around the IC engine which must be extracted out of the IC engine. Further, IC engine contains many reciprocating, rotating and moving parts and such movements cause friction between all surfaces in contact. At points of movement and extreme loading serious damage can be caused without proper lubrication. Hence, it is essential to circulate the engine oil to all the parts of the IC engine in oil passages. This is achieved by using oil pump which circulates engine oil under pressure. This helps in cooling the various parts of the IC engine, reducing wear on moving parts and absorbs shock loads. An oil cooler is usually employed in such engine oil cooling systems which form a heat exchanger wherein the hot engine oil is cooled and the cooled engine oil is circulated back for the next cycle in a closed loop system. Within the oil cooler, the engine oil is made to pass through long circulatory passages and constant flow of air is passed through its core to extract the heat from the engine oil. Generally, in two wheeled vehicles the oil cooler is disposed towards the front of the two wheeled vehicle. Further, the oil cooler utilizes incoming air from the front during motion or employs aid of external cooling fan to circulate air around the oil cooler. Such engine oil cooling systems have the drawback of circulating hot engine oil around the crankcase for cooling and lubrication especially after cooling the combustion chamber and cylinder head. The engine oil should always have correct viscosity to flow easily to all parts of the IC engine. Further, the need for external oil cooler necessitates additional space to accommodate the oil cooler and associated inlet cooler passage, outlet cooler passage and also brackets required to mount and hold them in position. Furthermore, the circulation of hot oil from the combustion chamber can reduce the life of an oil filter element thus necessitating frequent replacement of oil filter. Hence, there is a need to have a robust cooling solution for a saddle type vehicle in order to alleviate one or more drawbacks highlighted above.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.

[0004] Fig. 1. illustrates the side view of a two wheeled vehicle employing an embodiment of the present subject matter.

[0005] Fig. 2. illustrates the isometric view of an internal combustion engine employing the embodiment of the present subject matter.

[0006] Fig. 3. illustrates the enlarged view of the engine oil circulation path and an integrated oil cooler according to the embodiment of the present subject matter.

[0007] Fig. 4a. illustrates the perspective view of a cylinder block according to the embodiment of the present subject matter.

[0008] Fig. 4b. illustrates the side view of the cylinder block according to the embodiment of the present subject matter.

[0009] Fig. 5. illustrates the exploded view of the integrated oil cooler according to the embodiment of the present subject matter.

[00010] Fig. 6a. lustrates the cut sectional view of the cylinder block with the integrated oil cooler according to the embodiment of the present subject matter. [00011] Fig. 6b. illustrates the bottom view of a cylinder head according to the embodiment of the present subject matter.

[00012] Fig. 6c. illustrates the cut cross sectional view of the cylinder block with the integrated oil cooler and a crankcase of the internal combustion engine according to the embodiment of the present subject matter.

[00013] Fig. 7a. illustrates the front view of the integrated oil cooler according to the embodiment of the present subject matter.

[00014] Fig. 7b. and Fig. 7c. illustrates the front view of the integrated oil cooler showing different circulatory path designs according to the another second and third embodiment of the present subject matter.

[00015] Fig. 8. depict curves representing better cooling of the engine oil according to the embodiment of the present subject matter.

DETAILED DESCRIPTION

[00016] Various features and embodiments of the present subject matter here will be discernible from the following further description thereof, set out hereunder. According to an embodiment, an internal combustion engine (IC) described here operates in four cycles and comprises of a single cylinder with oil cooling system. Such an IC engine is installed in a straddle type vehicle. It is contemplated that the concepts of the present invention may be applied to other types of vehicles such as two wheeled vehicles with step-through frame within the spirit and scope of the present subject matter. Further "front" and "rear" , and "left" and "right" referred to in the ensuing description of the illustrated embodiment refer to front and rear, and left and right directions as seen from a rear portion of the IC engine and looking forward. Furthermore, a longitudinal axis unless otherwise mentioned, refers to a front to rear axis relative to the engine, while a lateral axis unless otherwise mentioned, refers generally to a side to side, or left to right axis relative to the engine. The detailed explanation of the constitution of parts other than the present subject matter which constitutes an essential part has been omitted at suitable places.

[00017] Typically, an IC engine comprises a cylinder block having a cylinder bore, a piston reciprocating in the cylinder bore, a cylinder head located above the cylinder block and a combustion chamber formed between the cylinder head, a top surface of the piston, and walls of the cylinder bore. Air fuel mixture is ignited in the combustion chamber which expands imparting reciprocating motion to the piston which is converted to rotary motion of a crankshaft through a connecting rod. Further, the motion from the crankshaft is transmitted to wheels of the vehicle through a transmission system. Typically, IC engines have a lot of reciprocating and moving parts. It is essential that such moving parts remain well lubricated for its operation under all conditions of operation. Additionally, it is essential to perform cooling to critical parts of the IC engine. Hence, an effective lubrication and cooling system which is robust is essential in all IC engines. A good lubrication and cooling system ensures long life of the IC engine, maximizes power output, increases efficiency, and improves reliability.

[00018] Generally in modern IC engines, a force-feed oil supply system is used to lubricate and cool the IC engine parts. In a force-feed oil supply system, an oil pump pressurizes the oil from an oil reservoir, which is then directed to various IC engine components through fixed oil passageways. The various IC engine components include crankcase, crankshaft, inner walls of cylinder bores, bearings, such as the main bearings, connecting rod, cylinder block, cylinder head including camshaft, and other components such as cam lobes rocker arms etc. The oil reservoir is usually disposed in the lower part of the IC engine crankcase. An oil filter is also used in this lubrication circuit shown which filters the lubricating oil from foreign particles. The oil pump is usually a positive-displacement pump or a gear pump which is capable of delivering oil to the oil paths. The oil pump can be mounted at any suitable location of the crankcase and driven by the crankshaft, or independently mounted with an electric motor. [00019] The cooling function of the force-feed oil supply system is to provide heat extraction from the surrounding parts of the cylinder head and cylinder block by the lubricating oil. Adequate cooling of the lubricating oil is necessary to maintain lubricating oil viscosity to flow easily to all parts of the IC engine and oil quality. To operate force-feed oil supply system cooling functions efficiently, the system includes a heat exchanger. The engine oil is cooled by passing hot engine oil through a heat exchanger typically called as oil cooler. Such a heat exchanger must be capable of achieving the required oil temperature drop when exposed to the maximum ambient air temperature for the application. Conventionally, the oil cooler is disposed exterior and separated from the IC engine and connected by inlet cooler passage and outlet cooler passage. The oil cooler is generally located front of the two wheeled vehicle wherein flow of air is obtained when the two wheeled vehicle is moving by taking advantage of the impinging air flow from a front direction

[00020] Conventionally in forced-feed oil supply system, the engine oil is circulated around the combustion chamber and then drained to the crankcase. The engine oil in the crankcase is then circulated in the crankcase before entering the oil cooler. Such systems have the drawback of circulating hot engine oil around the crankcase for lubrication and cooling. As highlighted above, the engine oil should always have correct viscosity to flow easily to all parts of the IC engine, otherwise if temperature is high the fluid film becomes thinner and some of the undesired forces may be transmitted between the surfaces of the moving parts. This impedes lubrication ability of the engine oil and also the ability to extract further heat from the engine crankcase. Further, the need for external oil cooler necessitates additional space to accommodate the oil cooler and associated inlet cooler passage, outlet cooler passage and also brackets required to mount and hold them in position. Furthermore, the circulation of hot oil from the combustion chamber can reduce the life of an oil filter element thus necessitating frequent replacement of oil filter. [00021] To address this problem of cooling the engine oil, various solutions are known in art. In one solution, a small cooling part can be disposed on the cylinder block and comprises a cooling oil passageway forming part of the upstream circuit when the engine oil is supplied from the crankcase to the cylinder head. But, such a cooling part is primarily to improve the lubricating effectiveness of engine oil during lubrication of valve train mechanism in cylinder head. Further, the cooling is effected by external fins outside the cooling part. But, in some IC engines especially higher capacities (above 200cc) require an external oil cooler. The cooling requirements include cooling the combustion chamber, spark plug and exhaust zone. The cooling part proposed above cannot be implemented on such IC engines as cooling capacity is less and it is very essential to cool the engine oil after cooling the combustion chamber and cylinder head before being recirculated back through the crankcase, oil pump and oil filter. Further, implementing the cooling part proposed above would require very effective heat extraction, and the cooling part having small surface area and limited number of fins cannot extract enough heat to meet the cooling requirements. Hence, an external oil cooler should be used in such IC engines.

[00022] Hence, to obviate the limitations, the proposed subject matter discloses, an integrated oil cooler and IC engine, wherein the engine oil is cooled immediately after circulation of engine oil around the combustion chamber. The oil cooler is integrated to the cylinder block on a return path of engine oil after cooling the combustion chamber and is thermally isolated from the cylinder block through an air gap. The air gap ensures effective cooling of the engine oil. Further, the oil cooler can utilize either forced air cooling system or natural air cooling system to circulate around the integrated oil cooler. Further, the circuitous path of oil flow within the oil cooler can be designed based on cooling efficiency and IC engine design requirements. Furthermore, the integrated oil cooler comprises perpendicular projections around its outer surface called fins to further improve the rate of dissipation of heat. [00023] With the above design changes, the following advantages can be obtained such as, eliminating the need for an external oil cooler, better cooling and lubricating characteristics of engine oil, better flexibility in implementation of design, smooth performance of the IC engine and optimization of available space.

[00024] The present subject matter along with all the accompanying embodiments and their other advantages would be described in greater detail in conjunction with the figures in the following paragraphs.

[00025] Fig. 1 illustrates a right side view of a saddle -ride type vehicle (100), in accordance with an embodiment of the present subject matter. Arrows provided in the top right corner of first figure depicts direction with respect to the vehicle, wherein an arrow F denotes front direction, an arrow R indicates rear direction, an arrow Up denotes upward direction, and an arrow Dw denotes downward direction. In an embodiment, the saddle -ride type vehicle (100) of the present subject matter includes an internal combustion (IC) engine (101). In present embodiment, the two-wheeled vehicle (100) is interchangeably termed as the saddle -ride type vehicle (100) or the vehicle (100). The vehicle (100) further includes a front wheel (110), a rear wheel (103), a body frame, a fuel tank (107) and seat (106). The Body frame includes a head pipe (111), a main tube (112), a down tube (113), a pair of seat supporting structures (117) and seat rails (not shown) disposed between the pair of seat supporting structures. The head pipe (111) supports a steering shaft (121) with two brackets D upper bracket (not shown) and lower bracket (120) at each end. Two telescopic front suspension (114) (only one shown) is attached to the lower bracket (120) on which is supported the front wheel (110). The upper portion of the front wheel (110) is covered by a front fender (115) mounted to the lower portion of a front fork of the telescopic front suspension (114). A handlebar assembly (108) is fixed to upper bracket and can rotate to both sides. A headlamp assembly (109) is disposed in the front portion of the headtube (111). Down tube (113) is disposed in front of the IC engine (101) and stretches slantingly downward from head pipe (111). A bracket (116) is provided at the lower end of the down tube (113) for supporting the IC engine (101) on the down tube (113). Main tube (112) is located above the IC engine (101) and stretches rearward from the head pipe (111) and connects to the rear of the IC engine (101). The seat supporting structure (117) is joined to the rear end of the main tube (112) and stretches rearward. The seat rails, which are joined to the main tube (112) and stretching rearward to support a seat assembly (106) disposed above these seat rails. Left and right rear swing arm bracket portions (not shown) support a rear swing arm (not shown) to swing vertically, and a rear wheel (103) is connected to rear end of the rear swing arm. Generally, two rear wheel suspensions (102) (only one shown) are arranged between rear swing arm. A tail lamp assembly (104) is disposed on the rear end of the seat supporting structure (117). A grab rail (105) is also provided on the rear end of the seat supporting structure (117). Rear wheel (103) is arranged below a seat assembly (106) and rotates by the driving force of the IC engine (101) transmitted through a chain drive (118) from the IC engine (101).

[00026] Fig. 2 illustrates a perspective view of the IC engine (101) employing the embodiment of the present subject matter. The IC engine (101) is made up of a cylinder head (203), cylinder block (204), a cylinder head cover (202) and crankcase (205). The cylinder block (204) comprises a cylinder bore (shown in Fig. 4a and Fig. 5), and a piston reciprocating in the cylinder bore (204a-shown in Fig. 4a and Fig. 5). A combustion chamber (207-shown in Fig. 4a, Fig. 5 and Fig. 6a) is interposed between the cylinder head (203) and the cylinder block (204) above the reciprocating piston wherein the burning of air fuel mixture occurs. An air intake system supplies the air fuel mixture to the cylinder head (203), which comprises intake valves and exhaust valves controlled by a valve train mechanism which permits the air fuel mixture inside the combustion chamber (207) and expels exhaust gases after combustion. The valve train mechanism is controlled by a camshaft disposed on the cylinder head (203) which in turn actuates the valve train mechanism. During normal use of the IC engine (101), the valve train mechanism requires constant cooling and lubrication for smooth operation of the various components. The crankcase (205) is made up of left-hand crankcase (205b) and right-hand crankcase (205a). A crankshaft is disposed within the crankcase (205) which receives the reciprocating motion of the piston by a connecting rod and is converted to rotary motion by slider crank mechanism.

[00027] The IC engine (101) also has a sprocket (not shown) disposed outside (on the other side) of the LH crankcase (205b) and is linked to the rear wheel (103) with the chain drive (118). In the present embodiment, the IC engine (101) is an oil cooled engine utilizing engine oil for cooling the combustion chamber (207) and the cylinder head (203). The engine oil is circulated around the combustion chamber cooling jackets disposed around the combustion chamber (207) to extract heat and consequently cool the surroundings around the combustion chamber (207) and cylinder block (204). As a consequence, a heat exchanger (201) is required which functions to cool the hot engine oil to enable cooler engine oil to re-circulate throughout the IC engine (101). In the present subject matter, an integrated oil cooler (201) is proposed which is integrally disposed on at least one face of the cylinder block (204). The integrated oil cooler (201) receives the engine oil immediately after its circulation around the combustion chamber (207) and hence disposed on the cylinder block (204). Further, the integrated oil cooler (201) is thermally isolated from the cylinder block through an air gap (401— shown in Fig. 3, Fig. 4a, Fig. 4b and Fig. 6a) and is cooled by either exposing it to the natural flow of atmospheric air or by an forced air cooling system which cools the oil before it circulates back into the IC engine (101) crankcase (205). The air gap (401) is essential for preventing the cylinder block (204) from the heat and isolates it, preventing it from increasing the temperature in the integrated oil cooler (201). In the present embodiment, the integrated oil cooler (201) is disposed on the front face of the cylinder block (204) facing towards the front of the vehicle (100). This exposes the integrated oil cooler (201) to the natural flow of air during operation. This air circulation around the integrated oil cooler (201) and the air gap (401) is sufficient to extract heat.

[00028] The oil cooling system comprises various components circulating the engine oil throughout the various components of the IC engine (101). The oil reservoir (not shown) stores the engine oil and is disposed at the bottom portion of the crankcase (205). There is also a drain plug (310) located on the underside of the crankcase (205) though which the engine oil can be drained. The oil reservoir also comprises an oil strainer (not shown) submerged inside which filters large particles and impurities in the engine oil and prevents them from entering the main oil passageways. The engine oil cooling system comprises a closed loop network of passageways found in both the LH crankcase (205b) and RH crankcase (205a) which is the path the engine oil takes circulating throughout the various components of the IC engine (101). An oil pump (not shown) operates upstream of the oil strainer to circulate the engine oil throughout the entire network of passageways. The oil pump can operate as a plunger-type oil pump or gear-feed oil pump which may be coupled directly to one of the shaft (not shown) of the IC engine (101). There is also an oil filter (not shown) to filter more particles before being circulated. The engine oil is circulated through a network of passageways to cool and lubricate IC engine (101) components such as plurality of combustion chamber cooling jackets (301 , 302- shown in Fig. 3) around the combustion chamber (207), crank-train passageways to cool and lubricate crank-train systems (such as crankshaft, crankshaft bearing, connecting rod, connecting rod bearing and piston skirt through splash lubrication), and cylinder head oil passage (303) to cool and lubricate cylinder head systems (such as camshaft, rocker arms, cam lobe and camshaft bearings). Once, the engine oil is circulated around the various oil galleries highlighted above, the engine oil drains into the oil reservoir. The engine oil lubricating the valve train mechanism through the cylinder head oil passage (303-shown in Fig. 3) drains through a cam chain window (304-shown in Fig. 3).

[00029] Fig. 3 illustrates the enlarged view of the engine oil circulation path and the integrated oil cooler (201) according to the embodiment of the present subject matter. There is an oil path which extends from the crankcase to the cylinder head (203). The lubricating oil is divided into two paths once it reaches the combustion chamber (207). One path forms the two combustion chamber cooling jackets (301 , 302), while the other path forms the cylinder head oil passage (303). The cylinder head oil passage (303) transverses through the cylinder block (204) through an oil path co-axial to one of a stud hole (305) to reach the cylinder head (203) and once it reaches the valve -train mechanism, the lubricating oil is made to circulate around the camshaft, rocker arms, the intake valves, outlet valves and various other components of the valve train mechanism. The two combustion chamber cooling jackets (301, 302) surround the combustion chamber to extract heat. It comprises a lower cooling jacket (301), one half of which is disposed on the cylinder block (204) and the other half is disposed on the cylinder head (203). The upper cooling jacket (302) circulates on the cylinder head (203) above the combustion chamber (207). The engine oil splits into two paths to circulate the upper and lower cooling jacket (301 and 302) before draining into an oil inlet passage (505) to the integrated oil cooler (201).

[00030] Fig. 4a illustrates the isometric view of the cylinder block (204) and the Fig. 4b illustrates the side view of the cylinder block (204) according to the embodiment of the present subject matter. In the present embodiment, the integrated oil cooler (201) is disposed on the rear face of the cylinder block (204). The integrated oil cooler (201) comprises an outer support member (206) within which the other components of the integrated oil cooler (201) are disposed. In one embodiment, the outer support member (206) is integrally attached to the cylinder block (204) and can be manufactured in a single casting process and further machining. There is the air gap (401) disposed between the outer support member (206) and the face of the cylinder block (204). This air gap (401) permits air flow to be circulated and hence increases the surface area for extraction of heat. The outer support member (206) further comprises plurality of cooling fins (206b) casted integrally and projected perpendicularly towards the direction of the air gap (401). The plurality of cooling fins (206b) further aid in removal of heat of air circulation within the air gap (401). After circulating around the combustion chamber (207), the engine oil drains into the oil inlet passage (505) which permit entry into the integrated oil cooler (201). The oil inlet passage (505) is disposed on the upper portion of the outer support member (206) and connects the combustion chamber cooling jackets (301, 302) to the oil circulation path (504). [00031] Fig. 5 illustrates the exploded view of the integrated oil cooler (201) according to the embodiment of the present subject matter. The integrated oil cooler (201) comprises the oil circulation path (504) originating from the oil inlet passage (505) and extends till an oil outlet passage (506) disposed within the outer support member (206), a cover plate (501) enclosing the oil circulation path (504), and a sealing member (503), in present embodiment the sealing member is an O- ring (503) disposed between the cover plate (501) and an inner flat surface (206a) of the outer support member (206). The inner flat surface (206a) of the outer support member (206) comprises of plurality of threaded holes (206c), matching with corresponding holes on the cover plate (501). The oil circulation path (504) is covered by the cover plate (501) by abutting it on the inner flat surface (206a) of the outer support member (206) and securing it by means of plurality of fasteners (502). The cover plate (501) encloses the oil circulation path (504) and thus sealing to prevent them from leaking out of the oil paths. The O-ring (503) is interposed between the cover plate (501) and the outer support member (206) and acts as the sealing member (503) preventing outside contaminants from entering inside and preventing engine oil leakage to outside. The engine oil after emerging from the combustion chamber cooling jackets (301 , 302) passage enters the oil circulation path (504) and travels a long and circuitous path and thus heating up the outer support member (206) and the cover plate (501). This heat is radiated outside, and when cooling air is circulated around the integrated oil cooler (201) and the air gap (401), cooling air removes the heat away from it. This process is further assisted by the presence of the plurality of cooling fins (206b) on the rear portion of the outer support member (206) as well as the plurality of fins (501a) on the cover plate (501). Hence, the integrated oil cooler (201) functions as the heat exchanger (201) cooling the hot engine oil just after emerging from the combustion chamber (207).

[00032] Fig. 6a illustrates the partly cut sectional view illustrating the inlet oil passage (505) according to the embodiment of the present subject matter. It is seen that, the inlet oil passage (505) is L-shaped, providing entry for the oil circulation path (504). Fig. 6b illustrates the bottom view of the cylinder head (203) illustrating the exit of engine oil from the upper cooling jacket (302). When the cylinder head (203) is assembled over the cylinder block (204), the exit of the upper cooling jacket (302) coincides exactly with the inlet oil passage (505). Fig. 6c illustrates the partly cut sectional view illustrating the outlet oil passage (506). Here, the cylinder head (203) gets cooled oil in the circulation path (504) and then oil exits to the LH crankcase (205b) through the outlet oil passage (506). The outlet oil passage (506) is also L-shaped and drains the engine oil back to the crankcase to join a main oil passage (306).

[00033] Fig. 7a illustrates the front view of the integrated oil cooler according to the embodiment of the present subject matter. The oil circulation path (504) is shaped as shown in Fig 7a. Here, the oil circulation path (504) taken is alternatively made to flow horizontally and vertically across three rows in a serpentine path (504). This arrangement maximizes the surface area for which the engine oil should flow in the integrated oil cooler (201). Fig. 7b and Fig. 7c illustrates the front view of the integrated oil cooler (201) showing different circulatory path designs according to second and third embodiment of the present subject matter. In Fig. 7b the oil circulation path (504a) is made to flow in predominantly vertical paths across 5 columns where the oil is coming through the inlet oil passage (505a) and exits through the outlet oil passage (506a). In Fig. 7c the oil circulation path (504b) is made to flow predominantly horizontal paths across 5 rows where the oil is coming through the inlet oil passage (505b) and exits through the outlet oil passage (506b). Based on the rate of heat extraction by the integrated oil cooler (201) various designs of the oil circulation path (504) can be adopted.

[00034] Fig. 8. depict curves (801 ,802) representing better cooling of the engine oil according to the embodiment of the present subject matter. The curves (801 ,802) are plotted between temperature (Celsius) and time (second). The first curve (801) is made in accordance with the known art where the heat exchanger (201) is disposed in close proximity with at least one face of the cylinder block (204). Due to above-mentioned known art of the heat exchanger (201), the heat exchanger (201) remains close to the heat zone present on the face of the cylinder block (204) and the temperature of the engine oil remains high as shown through the first curve (801) and thus the heat exchanger (201) is not effective and robust. However, when the air gap (401) is introduced between the heat exchanger (201) and at least one face of the cylinder block (204) in accordance with the present subject matter then the temperature of the engine oil falls significantly as shown through the second curve (802). As the presence of the air gap (401) provides isolation between the heat exchanger (201) and the heat zone present on the face of the cylinder block (204) which causes a temperature fall of the engine oil for increased cooling efficiency of the engine oil. Ultimately, the performance of the IC engine (101) also improves through optimization of available space.

[00035] It will be appreciated that the present subject matter and its equivalent thereof offers many advantages, including those which have been described forthwith. Many modifications and variations of the present subject matter are possible in the light of above disclosure. Therefore, within the scope of claims of the present subject matter, the present disclosure may be practiced other than as specifically described.

Claims

1/ We claim:

1. A vehicle (100) comprising: an internal combustion (IC) engine (101), said internal combustion (IC) engine (101) comprising: a crankcase (205); a cylinder block (204) disposed above said crankcase (205); a cylinder head (203) disposed above said cylinder block (204) to form a combustion chamber (207) interposed between said cylinder head (203) and said cylinder block (204); plurality of oil passages (505,506) for circulating engine oil under pressure in a closed loop to perform cooling and lubrication of components of said IC engine (101) including said combustion chamber (207), said cylinder block (204) and said cylinder head (203); and a heat exchanger (201) configured to perform cooling of the engine oil is disposed on at least one face of said cylinder block (204), said heat exchanger (201) separated from at least one face of said cylinder block (204) through an air gap (401).

2. The vehicle (100) as claimed in claim 1, wherein the plurality of oil passages (505,506) comprising of a combustion chamber cooling jacket (301, 302) surrounding the combustion chamber (207) and a cylinder head oil passage (303).

3. The vehicle (100) as claimed in claim 1 or claim 2, wherein the heat exchanger (201) configured to receive engine oil from the plurality of oil passages (505,506) after circulation around the cylinder head (203) and the combustion chamber (207).

4. The vehicle (100) as claimed in claim 1 or claim 2, wherein the heat exchanger (201) comprising: an outer support member (206) integrally attached to any one of four faces of the cylinder block (204);

the oil inlet passage (505) and the oil outlet passage (506) disposed on the outer support member (206);

an oil circulation path (504) originating from the oil inlet passage (505) and extends till the oil outlet passage (506) disposed within the outer support member (206); a cover plate (501) enclosing a serpentine oil path (504), said cover plate (501) secured to the outer support member (206) by means of plurality of fasteners (502); and a sealing member (503) disposed between the cover plate (501) and the outer support member (206).

5. The vehicle (100) as claimed in claim 1, wherein the combustion chamber cooling jacket (301, 302) is connected to the oil inlet passage (505) disposed on the heat exchanger (201), said combustion chamber cooling jacket (301, 302) configured to permit the egress of engine oil to the heat exchanger (201) after circulation.

6. The vehicle (100) as claimed in claim 1, wherein the outer support member (206) comprises plurality of cooling fins (206b), and the plurality of cooling fins (206b) projecting in a direction towards the air gap (401).

7. The vehicle (100) as claimed in claim 1 or claim 4, wherein the heat exchanger (201) is cooled either by naturally air cooled system or forced air cooling system.

8. The vehicle (100) as claimed in claim 1 or claim 4, wherein the oil circulation path (504) is the serpentine path (504), wherein the serpentine path (504) is one of horizontally oriented opposing path, vertically opposing path, and combination of horizontally and vertically oriented paths.

9. The vehicle (100) as claimed in claim 1, wherein the cylinder head oil passage (303) transverses through the cylinder block (204) through an oil path co-axial to one of a stud hole (305) to reach the cylinder head (203).

10. The vehicle (100) as claimed in claim 1, wherein the outlet oil passage (506) is L-shaped.

11. The vehicle (100) as claimed in claim 1 or claim 2, wherein the two combustion chamber cooling jackets (301, 302) comprises a lower cooling jacket (301) and an upper cooling jacket (302), wherein one half of the lower cooling jacket (301) is disposed on the cylinder block (204) and the other half is disposed on the cylinder head (203).