[001] The present subject matter described herein, relates to structure of a water jacket in an internal combustion engine and, in particular, to the water jacket structure for cylinder head to accommodate an integrated exhaust manifold. The present internal combustion engine may be naturally aspirated or turbocharged, Port Fuel Injection (PFI) or Direct injection engine for all fuel type.
BACKGROUND OF THE INVENTION:
[002] Conventionally, an Engine has individual intake port and exhaust port for each cylinder where water-jacket is not extended till end of exhaust port.
[003] As shown in fig. 1a and 1b, an Integrated Exhaust manifold 103 type cylinder Head 101 has been designed with water jacket 105a and 105b extended over and below Exhaust port respectively. The water jacket is provided to bring down exhaust gas temperature in full load condition at higher RPM. Due to compact size of cylinder head, manufacturing of Cylinder Head having Exhaust port core assembled with water jacket is not possible. To ensure that core assembly is possible during casting, water jacket has been split into lower water jacket 105b and upper water jacket 105a. Further, the lower water jacket 105b and the upper water jacket 105a is connected again within cylinder head, generally by multiple machined drill connections, to provide flow of coolant from the lower water jacket 105b to the upper water jacket 105a.
[004] Referring fig. 1c and 1d together which indicates flow circuit or path of coolant in the water jacket structure. The water jacket structure comprises a water jacket structure for cylinder head and water jacket structure for cylinder block. A water pump 202 is connected with the water jacket structure 105, 106 to supply coolant. The coolant enters from point 202a and exist from point 205 which coupled with thermostat housing.
[005] Referring fig. 1d and 1e together indicating coolant flow circuit in the water jacket structure 105 for cylinder head having upper water jacket 105a and lower water jacket 105b. As shown in fig. 1d and 1e, the water pump or pump 202 pumps the water or coolant in the water jacket for cylinder block at step 203. At step 204, the coolant flow from the water jacket for cylinder block to the water jacket for cylinder head. At step 205, the coolant flow from the water jacket for cylinder head to the thermostat housing for flow toward radiator for cooling. At step 206, coolant flow into heater circuit from the upper water jacket of cylinder head for cabin heating. In the fig. 1e, at step 203, the coolant flow from the water jacket for cylinder block to the lower water jacket of the water jacket structure for cylinder head and then flow to the upper water jacket of the water jacket structure for cylinder head. At step 205, the coolant coming from the upper water jacket flow towards the thermostat housing, heater circuit and EGR cooler.
[006] In the conventional design where the upper water jacket is connected with the lower water jacket for flow of coolant or water from the water jacket for cylinder block has several technical disadvantages which are:
[007] All coolant is flowing through entire water jacket structure of cylinder Head in thermostat closed condition leading to delay in engine warp up.
[008] Another technical problem: Pressure loss within water jacket structure for cylinder head is more in the conventional system due to connection of lower water jacket and upper water jacket in series.
[009] Yet another technical problem: In the existing split water jacket structure for cylinder head, it is more difficult to precisely control metering of coolant flow to exhaust valve seats which are under significant thermal stress.
[0010] Therefore, there is a need in the art to provide a technical solution that can overcome the above mentioned technical problems without changing the method of manufacturing of the water jacket structure and without adding extra cost to the existing structure.

OBJECTS OF THE INVENTION:
[0011] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed herein below.
[0012] The principal object of the present invention is to provide a water jacket structure for cylinder head to improve fuel economy by warming up the coolant at early stage.
[0013] Another object of the present subject matter is to provide a water jacket structure for cylinder head to reduce pressure drop and improve efficiency of water or coolant pump.
[0014] Another objective is to provide better control of coolant flow to exhaust valve seat inserts to have better wear characteristics and exhaust valve bridge temperatures for better durability by having no direct coolant flow connection between upper and lower water jackets. This allows for relatively independent control of temperatures.
[0015] These and other objects and advantages will become more apparent when reference is made to the following description and accompanying drawings.
SUMMARY OF THE INVENTION:
[0016] This summary is provided to introduce concepts related to structure of a water jacket for cylinder head in an internal combustion engine. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0017] In an embodiment, the present subject matter relates to a water jacket structure for a cylinder head of an internal combustion engine. The water jacket structure comprising: an upper water jacket structure; a lower water jacket structure; the upper water jacket structure connected to a thermostat housing; and the lower water jacket structure connected to an Exhaust Gas Recirculation (EGR) cooler. The coolant flow passage to the lower water jacket structure from cylinder block is separate from coolant flow passage to the upper water jacket structure from the cylinder block.
[0018] In an aspect, an integrated exhaust manifold is arranged in between the upper water jacket structure and the lower water jacket structure.
[0019] In another embodiment, the present subject matter relates to a method for flow of coolant or water in the water jacket structure. The method comprising: flowing coolant from a pump to a water jacket structure for cylinder block; flowing the coolant from the water jacket structure for cylinder block to an upper water jacket structure and a lower water jacket structure for cylinder head; flowing the coolant in a coolant flow passage to the lower water jacket structure from the cylinder block which is separated from a coolant flow passage to the upper water jacket structure from the cylinder block.
[0020] In an aspect, the method further includes the flowing comprising: flowing the coolant from the EGR cooler to the pump.
[0021] In an aspect, the method further includes the flowing comprising: flowing the coolant from the thermostat housing to a radiator; and flowing the coolant from the radiator to the pump.
[0022] In an aspect, the water jacket structure comprises the water jacket structure for cylinder head and the water jacket structure for cylinder block.
[0023] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with 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
[0024] 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 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 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:
[0025] Fig. 1a illustrates assembly of integrated exhaust manifold with cylinder head of internal combustion engine;
[0026] Fig. 1b illustrates water jacket structure extended over and below exhaust port and integrated exhaust manifold;
[0027] Fig. 1c illustrates coolant flow within engine for existing structure of the water jacket structure;
[0028] Fig. 1d illustrates schematic diagram for coolant flow circuit as indicated in fig. 1c of existing conventional device. Fig. 1d illustrate schematic diagram having single piece water jacket in cylinder head and Fig. 1e illustrate schematic diagram where water jacket in Cylinder Head is split into lower water jacket and upper water jacket;
[0029] Fig. 2 illustrates water jacket structure for cylinder head, in accordance with an embodiment of the present subject matter;
[0030] Fig. 3 illustrates schematic diagram for coolant flow circuit of complete vehicle including water jacket structure of engine as shown in fig. 2, in accordance with an embodiment of the present subject matter; and
[0031] Fig. 4 illustrates method for coolant flow in the water jacket structure for cylinder head as explained in Fig. 3, in accordance with an embodiment of the present subject matter.
[0032] The figures depict embodiments of the present subject matter for the 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:
[0033] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
[0034] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a",” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the tennis “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0036] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0037] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0038] These and other advantages of the present subject matter would be 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.
[0039] In the present water jacket structure for cylinder head, a parallel flow is provided in between lower water jacket structure and upper water jacket structure for solving the technical problems as explained in background section. The output of the coolant from the lower water jacket is connected to the EGR cooler and the output of the coolant from the upper water jacket is connected to thermostat housing. Similar connection can be used for other heat exchanger also like cabin heater, oil warmer, CNG regulator heater or throttle body heater. The present parallel coolant flow arrangement has multiple technical advantages over conventional series coolant flow arrangement.
[0040] Referring to fig. 2 that illustrates structure of water jacket for cylinder head. The water jacket structure 300 comprises an upper water jacket structure 301 and a lower water jacket structure 302. As shown in fig. 1b, an integrated exhaust manifold is also arranged in between the upper water jacket structure 301 and the lower water jacket structure 302. In the arrangement, a lower portion of the integrated exhaust manifold is disposed above the lower water jacket structure 302 and an upper portion of the integrated exhaust manifold is disposed below the upper water jacket structure 301 for conduction of heat. With the present arrangement, the exhaust manifold has better cooling as compared to existing arrangement as heat is conducted at two levels with different coolant pressure and temperature.
[0041] In an embodiment, the upper water jacket structure 301 covers exhaust manifold and intake manifold where the lower water jacket structure 302 covers only exhaust manifold.
[0042] The inventive and novel feature of the present subject matter lies in parallel flow of coolant from the lower water jacket structure and the upper water jacket structure which is possible only when there is no coolant flow connection is provided in between the upper water jacket structure 301 and the lower water jacket structure 302. The upper water jacket structure 301 is connected to a thermostat housing 406 (as shown in fig. 3) for pushing the coolant towards the radiator 401 (as shown in fig. 3) for cooling. The lower water jacket structure 302 is connected to an Exhaust Gas Recirculation (EGR) cooler 407 (as shown in fig. 3). In the present structure, the coolant in the lower water jacket structure 302 flows independently from the upper water jacket structure 301 due to which pressure drop in coolant is minimum in the upper water jacket structure 301 and the lower water jacket structure 302.
[0043] Referring to fig. 4 and 5 together which illustrate coolant flow circuit in the present water jacket structure for cylinder head and water jacket structure for cylinder block. The complete water jacket structure comprises two parts one for cylinder head and another for cylinder block. The water jacket structure for cylinder head 300 is connected with the water jacket structure for cylinder block for flow of the coolant.
[0044] At flow circuit step 501, coolant flows from the pump 402 to the water jacket structure for cylinder block 403.
[0045] At flow circuit step 502, 501, the coolant flows from the water jacket structure for cylinder block 403 to the upper water jacket structure 405 and the lower water jacket structure 404 respectively.
[0046] At flow circuit step 503, the coolant flows from the lower water jacket structure 404 to an exhaust gas recirculation (EGR) cooler 407.
[0047] At flow circuit step 504, the coolant flows from the upper water jacket structure 405 to a thermostat housing 406.
[0048] In an embodiment, flowing coolant in a coolant flow passage to the lower water jacket structure 302 from the cylinder block 403 which is separated from a coolant flow passage to the upper water jacket structure 301 from the cylinder block 403.
[0049] At flow circuit step 505, the coolant flows from the EGR cooler 407 to the pump 402.
[0050] At flow circuit step 506, the coolant flows from the thermostat housing 406 to a radiator 401 for cooling or releasing the heat.
[0051] At flow circuit step 507, the coolant flows from the radiator 401 to the pump 402 for flowing the cooled coolant into the water jacket structure.
[0052] In an aspect, some portion of the coolant from the upper jacket structure 405 flow to heater circuit for supplying hot coolant and heater circuit send back the cooled coolant to pump 402 for re-circulation in the water jacket structure.
[0053] Technical advantages: there are a number of technical advantages which arise from the parallel flow of coolant in the upper water jacket structure and the lower water jacket structure. There is no coolant flow connection provided in between the upper water jacket structure and the lower water jacket structure.
[0054] In the present structure, the coolant flow in the thermostat closed condition is happening via lower water jacket structure which is below integrated exhaust manifold. The present arrangement and flow of coolant to lower water jacket structure help in early warm up of coolant and hence improvement of fuel economy. With the present arrangement, the exhaust manifold has better cooling as compared to existing arrangement as heat is conducted at two levels with different coolant pressure and temperature.
[0055] In the present coolant flow circuit as shown in fig. 3 and 4, flow resistance within the water jacket structure for cylinder head is reduced. Due to this work required by water pump or pump for same amount of coolant has been reduced. By taking advantage of this improvement, water pump drive ratio has been reduced and this has enabled further improvement in fuel economy.
[0056] Also the present arrangement and bifurcation of coolant flow in the water jacket structure results in better cooling of exhaust valve seats which allows for use of lower cost exhaust valve alloy (lower Ni content) giving advantage in terms of cost performance, as coolant flow through the lower water jacket structure can be adjusted independent of the upper water jacket structure now.
[0057] The present structure of split water jacket for cylinder head with novel and inventive parallel flow of coolant has helped to reduce exhaust gas temperature in full load condition at higher RPM due to which extra fueling to cool catalyst is no more required. Accordingly, lambda=1 zone in the engine has been increased by almost 100%. Due to the expansion of lean zone by such a large extend has helped in meeting real diving emission by reducing HC emission which was otherwise happening due use of rich mixture at high RPM to protect engine component particularly exhaust catalytic converter from getting over heated and burned due to high exhaust gas temperature.
[0058] This also results in improvement of fuel economy of vehicle at high driving speeds since extra fueling is no more required.
[0059] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations.
[0060] However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations).
[0061] Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.).
[0062] It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
[0063] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

Claims:We claim:
1. A water jacket structure (300) for a cylinder head with an integrated exhaust manifold, the water jacket structure (300) comprising:
an upper water jacket structure (301);
a lower water jacket structure (302) where the upper water jacket structure (301) and the lower water jacket structure (302) are part of cylinder head;
characterized in that
the upper water jacket structure (301) connected to a thermostat housing (406);
the lower water jacket structure (302) connected to an Exhaust Gas Recirculation (EGR) cooler (407),
where coolant flow passage to the lower water jacket structure (302) from cylinder block (403) is separate from coolant flow passage to the upper water jacket structure (301) from the cylinder block (403).

2. The water jacket structure (300) as claimed in claim 1, wherein the upper water jacket structure (201) covers exhaust manifold and intake manifold where the lower water jacket structure (302) covers exhaust manifold.

3. The water jacket structure (300) as claimed in claim 1, wherein separate coolant flow passages are provided from cylinder block (403) to the lower water jacket structure (302) and the upper water jacket structure (301).

4. A method (500) comprising:
flowing (501) coolant from a pump (402) to a water jacket block (403) in water jacket structure;
flowing (502) the coolant from the water jacket structure (403) for cylinder block to an upper water jacket structure (301, 405) and a lower water jacket structure (302, 404) for cylinder head;
flowing (503, 504) the coolant from a coolant flow passage to the lower water jacket structure (302) from the cylinder block (403) which is separated from a coolant flow passage to the upper water jacket structure (301) from the cylinder block (403).
5. The method (500) as claimed in claim 4, wherein the flowing (503) comprising:
flowing (505) the coolant from the EGR cooler (407) to the pump (402).
6. The method (500) as claimed in claim 4, wherein the flowing (504) comprising:
flowing (506) the coolant from the thermostat housing (406) to a radiator (401); and
flowing (507) the coolant from the radiator (401) to the pump (402) cooler (407) to the pump (402).
7. The method (500) as claimed in claim 4, wherein the water jacket structure comprises water jacket structure (300) for cylinder head and water jacket structure (403) for cylinder block.