WATER JACKET STRUCTURE FOR MULTI-CYLINDER INTERNAL COMBUSTION ENGINE
FIELD OF INVENTION:
[001] The present subject matter described herein, relates to cooling of multi-cylinder internal combustion engine, and in particular, to a water jacket structure 5 covering cylinder head of the internal combustion engine to cool the cylinder head. More particularly, the present subject matter relates to a water jacket structure for water cooled internal combustion engine having water deflectors and restrictors to increase the cooling efficiency of the engine.
BACKGROUND AND PRIOR ART: 10
[002] Normally, temperature of internal combustion engine is very high. Therefore a proper cooling is required to keep the internal combustion engine cool. If the temperature of the engine cylinder is too high, the fuel will prematurely reach at the ignition temperature during the compression stroke and uncontrolled combustion occurs in the combustion chamber. Further, this 15 uncontrolled combustion reduces the efficiency of the engine. This undesirable phenomenon is known as auto-ignition or “knock”, and creates inefficiencies in the engine operation. The hot spot can be created anywhere on the combustion chamber. Therefore, it is desirable to cool the cylinders and the cylinder head of the engine. Further, cooling the cylinder head and its surrounding areas, is 20 particularly troublesome because these areas are crowded with components, such as intake valve , exhaust valve and spark plug, and also because these areas experience particularly high heat flux. Furthermore, cooling of the cylinder head at the area between adjacent valves, i.e., between the intake valves, between the exhaust valves, and between the spark plug and valves is also problematic due to 25 heat buildup in this area.
[003] Generally, a water jacket structure provides a passageway through which cooling liquid flows in the cylinder head. In the water jacket, cooling fluid flows from the cylinder block water jacket towards cylinder head water jacket through 2
gasket holes. The cooling fluid flows in the water jacket to cool the cylinder head and cylinders. In the water jacket passageway, between adjacent cylinders there is no direct heat flux received since this location is in between two combustion chambers therefore there is little need for providing intensified cooling in this location of the cylinder head water jacket;, therefore providing cooling liquid in 5 this location reduces the effectiveness of the cooling liquid at the areas that need the cooling fluid most. Accordingly, areas of the cylinder head become overheated and such inconsistent cooling of the cylinder head may lead to auto-ignition or knock in the cylinder head.
[004] Due to circulation of water in areas between the cylinders where less 10 cooling is required, decreases the cooling fluid capacity to carry away heat from critical locations which reduces the overall cooling efficiency of the cooling fluid in the water jacket. Further, there is temperature difference between the cylinders of the plurality of cylinders of the internal combustion engine. Therefore, efficiency of the engine drops and wear and tear in the engine is more. 15
[005] Conventionally, in the water jacket of the cylinder head rectangular/vertical deflectors are placed in the area between the cylinders. Fig. 1(a) illustrates the deflector arrangement in the water jacket. As illustrated in the figure, the water jacket deflectors 102 are provided perpendicular to flow of cooling fluid. This approach is limited to engines with high performance but low 20 production volumes since design and manufacturing of such concepts required involved significant effort to meet tradeoff between pressure loss and cooling performance. Further, there is high pressure loss in water jacket as deflectors are placed directly as perpendicular barriers to flow of cooling fluid in the water jacket. This placement of deflectors increases the pressure loss in water jacket due 25 to which flow rate of cooling fluid reduces. Accordingly, the water jacket heat rejection capacity reduces.
[006] Further, design of water jacket with perpendicular deflectors leads to high level difficulty in manufacturing since these deflectors make the water jacket cores highly complicated due to intricate shapes. This leads to difficulty in terms 30
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of achieving flow of sand grains during manufacturing of sand cores in a homogeneous manner, since these deflectors meant for water flow obstruct sand grain flow in a similar manner.
[007] Another problem in the water jacket structure is to control and direct the flow of the cooling fluid in the water jacket structure. In conventional method of 5 directing cooling fluid in a generic manner by circulating coolant through cylinder head water jacket passage constructed in general manner. It is a very difficult to control flow of cooling fluid in the cylinder head water jacket. Further, it is very difficult to direct the cooling fluid to specific locations in critical locations like valve, valve seats, and spark plug. In the conventional water jackets, the stream of 10 the cooling fluid flows in the water jacket without cooling the critical point of cylinder head. Therefore, over heating of critical points of the cylinder head generates knock points for premature combustion in the combustion chamber.
[008] In another conventional method to cool the critical points, such as exhaust Valve Bridge of cylinder head, a hole is drilled above the valve bridge which 15 receives coolant at high velocity through an orifice in the cylinder head gasket. Fig. 2 illustrates drilled hole in the water jacket structure. But this primarily cools the exhaust valve bridge and effect on cooling of the other valve seats, such as intake valve and spark plug is only secondary. This approach is limited to engines with high performance mainly turbocharged engines to take care of high heat flux. 20 This lead to extra cost drilling a hole and manufacturing of the water jacket is very difficult and costly. Further, the other parts of the cylinder head does not receive proper cooling effect which reduces the thermal efficiency of the engine due to combustion phasing loss since spark timing needs to be retarded to prevent knockingand ultimately efficiency of the internal combustion engine. 25
[009] Furthermore, In-direct control of cooling fluid rate by control of orifice location and diameters in cylinder head gasket is not adequate to address high heat flux received at critical locations like valve seat and Valve Bridge. The control of cooling fluid velocity in the critical locations to increase heat transfer co-efficient cannot be achieved by controlling orifice diameter (hole cross-section area) in the 30
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water jacket and gasket. Further, by drilling a hole to control velocity and flow rate of the cooling fluid in the critical locations is only limited to exhaust valve bridge location in cylinder head. Direct control for valve seat locations, such as intake valve bridge and spark plug is not possible.
[0010] As the structure of water jacket known in the art does not mitigate knock 5 problem in the internal combustion engine. Further, the known structures are not configured to cool the critical regions of the cylinder head by maintaining uniform temperature across the cylinder head in each cylinder block/chamber. Accordingly, there exists a need in the art for a water jacket structure in cylinder head having appropriate distribution of cooling fluid to ensure efficient cooling of 10 each part of the cylinder head. There also exists a need in the art for a flow control deflector and restrictor in the water jacket passageway that will assist the cooling fluid the flow in the most critical areas of the cylinder head with minimum pressure loss and ease of manufacturing.
OBJECTS OF THE INVENTION: 15
[0011] The principal objective of the present invention is to provide a water jacket structure having cylindrical deflector.
[0012] Another object of the present subject matter is to provide a water jacket structure having restrictor at end of combustion chamber.
[0013] Another object of the present invention is to achieve high heat transfer 20 coefficient at critical locations of the cylinder head.
[0014] Another object of the present invention is to mitigate hot spots in the cylinder head and combustion chamber to mitigate knocking phenomena.
[0015] Yet another object of the present invention is to provide easy manufacturing of water jacket structure. 25
[0016] Yet another object of the present invention is to achieve high thermal efficiency of the internal combustion engine.
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[0017] Yet another object of the present subject matter is to minimize the pressure drop loss of the cooling fluid in water jacket structure.
[0018] Yet another object of the present invention is to provide efficient cooling of critical points of water jacket structure.
[0019] Yet another object of the present invention is to achieve uniform 5 temperature across each combustion chamber of the water jacket structure over cylinder head.
[0020] Yet another object of the present invention is to divert cooling fluids from non critical points in the water jacket to critical points in the water jacket structure. 10
[0021] Yet another object of the present invention is to increase durability of the valve train component by decreasing wear and tear of the valves & valve seat by maintaining the temperature of the internal combustion engine
SUMMARY OF THE INVENTION:
[0022] The present subject matter disclosed herein relates to a water jacket 15 structure is provided for cooling cylinder head of multi-cylinder engine. The present water jacket structure has a cylindrical deflector which is provided between the combustion chambers where negligible cooling is required. The deflector diverts the cooling fluid away from the non-critical areas to critical areas of the cylinder head, such as intake valve bridge, exhaust valve bridge, and spark 20 plug. Diverting the cooling fluid to the critical areas mitigate the knock problem in the combustion cylinder. Further, better cooling efficiency is achieved. Furthermore, diverting the fluid from the non-critical points using cylindrical structure with a split which reduces the pressure loss in the water jacket structure.
[0023] In another embodiment of the present subject matter, the water jacket 25 structure is provided with a plurality of restrictors. Each restrictor from the plurality of restrictors is placed at end of each combustion chamber of the water jacket structure. The restrictor at the end of each cylinder/combustion block diverts flow of cooling fluid from tuned cylinder head gasket orifice to exhaust 6
valve bridge, exhaust valve bridge, and spark plug. The present water jacket structure with restrictors at the end achieve high heat transfer coefficient at critical locations by controlling cooling fluid flow in complex water jacket structure.
[0024] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with 5 reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be 10 considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and 15 components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0026] Fig. 1(a) and (b) illustrates perpendicular deflector in water jacket structure as known in the art; 20
[0027] Fig. 2 illustrates cylindrical deflector in the water jacket structure, in accordance with an embodiment of the present subject member;
[0028] Fig. 3 illustrates top view of the water jacket structure having cylindrical deflectors, in accordance with an embodiment of the present subject member;
[0029] Fig. 4 illustrates gasket structure, in accordance with an embodiment of the 25 present subject matter;
[0030] Fig. 5 illustrates water jacket structure with drilled hole to cool exhaust valve of the cylinder head as known in the art; 7
[0031] Fig. 6 illustrates the water jacket structure having restrictors at the bottom, in accordance with an embodiment of the present subject member; and
[0032] Fig. 7 illustrates exploded view of restrictor at the bottom of the water jacket structure, in accordance with the present subject matter.
[0033] The figures depict embodiments of the present subject matter for the 5 purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS: 10
[0034] The subject matter disclosed herein relates to a water jacket structure in cylinder head of a multi-cylinder internal combustion engine to cool the cylinder head. The water jacket structure is for water cooled internal combustion engine for cooling critical regions of the cylinder head. In the water jacket structure, there are deflectors provided in area between two adjacent combustion chambers where 15 least cooling is required. Further, the present jacket structure has multiple restrictors at the end of each combustion chamber of the water jacket structure which divert flow of cooling fluid to critical points of the combustion chamber.
[0035] Conventionally, the hotspots created in the cylinder head leading to premature combustion problem in the combustion chamber. The conventionally 20 available water jacket structure does not provide efficient cooling of all the critical points of the cylinder head. In the water jacket passageway, between adjacent cylinders there is no direct heat flux received since this location is in between two combustion chambers therefore there is little need for providing intensified cooling in this location of the cylinder head water jacket, therefore providing 25 cooling liquid in this location reduces the effectiveness of the cooling liquid at the areas that need the cooling fluid most. Accordingly, areas of the cylinder head become overheated and such inconsistent cooling of the cylinder head may lead to
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auto-ignition or knock in the cylinder head. Therefore, knock problem remains the same.
[0036] Another problem in the conventional water jacket structure is to control and direct the flow of the cooling fluid in the water jacket structure. In conventional method of directing cooling fluid in a generic manner by circulating 5 coolant through cylinder head water jacket passage constructed in general manner. It is a very difficult to control flow of cooling fluid in the cylinder head water jacket. Further, it is very difficult to direct the cooling fluid to specific locations in critical locations like valve bridges, valve seats and spark plug. In the conventional water jackets, the stream of the cooling fluid flows in the water 10 jacket without affecting the critical point of cylinder head. Further, over heating of critical points of the cylinder head generates knock points for premature combustion in the combustion chamber.
[0037] According to present subject matter, a water jacket structure is provided for cooling cylinder head of multi-cylinder engine. The present water jacket 15 structure has a plurality of cylindrical deflector which are provided between each two adjacent combustion chambers of the multi-cylinder engine where least cooling is required. Each deflector from the plurality of deflectors diverts the cooling fluid away from the non-critical areas to critical areas of the cylinder head, such as intake valve bridge, exhaust valve bridge, and spark plug. Diverting 20 the cooling fluid to the critical areas mitigate the knock problem in the combustion cylinder. Further, better cooling efficiency is achieved. Furthermore, diverting the fluid from the non-critical points avoid stagnation of cooling fluid which reduces the pressure loss in the water jacket structure.
[0038] In another embodiment of the present subject matter, the water jacket 25 structure is provided with a plurality of restrictors. Each restrictor from the plurality of restrictors is placed at end of each combustion chamber of the water jacket structure. The restrictor at the end of each combustion chamber diverts flow of cooling fluid from tuned cylinder head gasket orifice to exhaust valve bridge, exhaust valve bridge, and spark plug. The present water jacket structure with 30
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restrictors at the end achieve high heat transfer coefficient at critical locations by controlling cooling fluid flow in complex water jacket structure.
[0039] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily 5 utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples 10 recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the 15 present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0040] These and other advantages of the present subject matter would be 20 described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope. 25
[0041] Fig. 2 illustrates cylindrical deflector in the water jacket structure 200, in accordance with an embodiment of the present subject. The present water jacket structure 200 includes a plurality of holes for air intake valve 204, exhaust air outlet valve 206, spark plug 208, and a plurality of deflectors 202 (individually can be referred as deflector 202). Further, the cooling fluid enters in the water 30
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jacket 200 through water inlet 210 which is inline with orifice of gasket, and goes out from the water jacket structure 200 from the outlet 212 at top of the water jacket structure 200. The plurality of deflectors 202 is in cylindrical shape. Where the cylindrical shape of each of deflector from the plurality of deflectors 200 is achieved by combining two half cylindrical deflectors which are having equal 5 radius together. The structure of water jacket is very complex and cooling fluid has a smooth flow around the cylinder head in the water jacket structure 200. Each of the deflector from the plurality of deflectors 202 is provided between two adjacent cylinder chambers or combustion chambers of the multi-cylinder engine head where least cooling is required. The region between any two adjacent 10 combustion chambers for a given multi cylinder engine can be called as non-critical area for cooling. The multi-cylinder engine has at-least 2 cylinders in the engine. Further, the areas critical for cooling in the cylinder head are the combustion chamber, spark plug, intake valve and exhaust valve seats and valve bridge locations. Since these are the regions/areas where high heat flux is 15 generated during engine operating conditions. In the critical area more cooling is required as compare to non-critical area. Further, the non-critical area depends on the bore pitch of the cylinder. Where higher the bore pitches bigger the non critical area in the water jacket that does not require cooling specifically. Therefore, there is requirement to divert the cooling fluid entering in the non-20 critical areas to critical areas where more cooling is required.
[0042] The cylindrical deflector 202 in the water jacket structure 200 diverts the cooling fluid away from the non-critical areas to critical areas of the cylinder head. The cylindrical deflector 202 diverts the cooling fluid coming from water pump to critical areas. Further, the shape of the deflector is cylindrical which 25 reduces the pressure loss in the non critical area. Due to the cylindrical shape, the deflector 202 diverts cooling fluid towards the critical areas low pressure loss. Further, reduction in pressure loss leads to reduced cavitations tendency in the cooling circuit. If the pressure loss is less, water/fluid/coolant pump uses less fuel to circulate the cooling fluid in the water jacket structure 200. Accordingly, 30 efficiency of the water pump increases. 11
[0043] The cylindrical deflector 202 avoids stagnation of cooling fluid in the non-critical area by diverting the cooling fluid to the critical area. The present water jacket structure 200 with the plurality of cylindrical deflectors 202 cools the all critical area of the combustion cylinder and provide uniform temperature across the multiple cylinder chamber of the multi-cylinder engine head. Further, the 5 plurality of deflectors 202 provides efficient cooling of the cylinder head which mitigates the knock issue. Diverting the cooling fluid to the critical areas mitigate the knock problem in the combustion chamber. Further, better cooling efficiency is achieved.
[0044] Fig. 3 clearly illustrates the placement of the cylindrical deflector in the 10 water jacket structure 300. The cylindrical deflector 202 reduces the pressure loss in the water jacket and maintains a uniform flow of cooling fluid in the water jacket. Further, diversion of cooling fluid from the non-critical areas to critical areas increases component durability. Due to cylindrical deflector 202, the cooling fluid flows in every critical part of each combustion chamber. Accordingly, 15 uniform temperature in each combustion chamber of the engine can be achieved for better performance.
[0045] Fig. 4 illustrates cylinder head gasket which is placed between the cylinder head and water jacket. The gasket has plurality of orifices or holes to pump the cooling fluid into water jacket with help of water pump. The plurality of orifices 20 in the gasket is tuned with the water jacket structure to pump the cooling fluid inside the water jacket structure.
[0046] Fig. 6 illustrates the water jacket structure having restrictor at end of a particular cylinder/combustion chamber. The water jacket structure 600 has multiple valve seats and a plurality of restrictors 602 (individually can be referred 25 as restrictor 602) at the end of each cylinder chamber in the multi cylinder engine. Where each restrictor from the plurality of restrictors 602 is in reverse ‘U’ shape with narrow cross section. Each restrictor from the plurality of restrictors 602 is provided at the end of each combustion chamber of the water jacket structure which surrounds each combustion chamber of the multi-cylinder engine. The 30
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restrictor 602
diverts flow of the cooling fluid received from tuned cylinder head gasket orifice to exhaust valve seat, exhaust Valve Bridge, and spark plug location. By using plurality of restrictors 602 in the water jacket controls both coolant discharge rates and coolant velocity at specific locations. Further, cooling of valve seat specifically exhaust valve seats and exhaust valve bridge is improved 5 by using plurality of restrictors 602.
[0047] In the present water jacket structure, direct control over cooling fluid flow throughout the water jacket is achieved by the use of plurality of restrictors 602.. Further, the placement of the restrictor 602 at the end of the combustion chamber of the water jacket structure 600 is in conjunction with controlled placement of 10 orifice in specified location with specific diameter as per overall water jacket structure.
[0048] The restrictor 602 secures high heat transfer co-efficient rates at critical locations by controlling cooling fluid flow in intricate complex water jacket structure. The flow cooling fluid from the water pump is restricted by the 15 restrictor 602 and it diverts the flow of the cooling fluid towards the critical area, i.e., exhaust valve seat, exhaust Valve Bridge, and spark plug location. Further, the restrictor 602 restricts entering of the cooling fluid in the non-critical area and diverts most of the cooling fluid towards critical area. Accordingly, high thermal efficiency in the combustion engine is achieved. By cooling the critical areas of 20 the combustion cylinder, better knock mitigation is achieved. Further, the present water jacket provides knock free operations while operating on high compression rations. By diverting the cooling fluid to the critical areas, durability of cylinder head components, such as valve, valve seats, and spark plug is increased. Further, rate of valve seat wear is reduced due to reducing thermal loading on the 25 components.
[0049] Fig. 8 illustrates the exploded view of the restrictor 602 in the water jacket structure. The restrictor 602 diverts the most of cooling fluid towards the critical areas of each cylinder chamber of the water jacket to achieve the uniform temperature. Further, the present water jacket structure can work effectively for 30
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dry fuel and direct injection engine where valve seat lubrication is negligible. The present water jacket structure helps in reducing wear rates of the components.
[0050] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, 5 the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/device of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter. 10
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We claim:
1. A water jacket structure (200) for cooling multi-cylinder engine head, the water jacket structure (200) comprising:
a plurality of holes to accommodate inlet valve, exhaust valve, and spark plug along with screw holes; 5
a plurality of deflectors (202), wherein each deflector from the plurality of deflectors (202) is provided between two adjacent combustion chambers of multi-cylinder engine head.
2. The water jacket structure (200) as claimed in claim 1, wherein the plurality 10 of deflectors (202) is in cylindrical shape.
3. The water jacket structure (200) as claimed in claim 1, wherein the each deflector (202) from the plurality of deflectors (202) is made by joining two half cylindrical parts having equal radius. 15
4. The water jacket structure (200) as claimed in claim 1, wherein the each deflector (202) from the plurality of deflectors (202) diverts flow of cooling fluid to critical area of cylinder head.
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5. The water jacket structure (200) as claimed in claim 1, wherein the each deflector (202) from the plurality of deflectors (202) reduces pressure loss in the cooling fluid inside the water jacket structure (200).
6. The water jacket structure (200) as claimed in claim 1, wherein the each 25 deflector (202) from the plurality of deflectors (202) is placed at non-critical area of cooling.
7. The water jacket structure (200) as claimed in claim 1, wherein the plurality of deflectors (202) avoid flow of cooling fluid in the non-critical area of 30 cooling.
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8. The water jacket structure (200) as claimed in claim 1, wherein the plurality of deflectors (202) provides uniform temperature across each cylinder head of the multi-cylinder engine head.