JP2014084737A - Water jacket structure of cylinder head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water jacket structure of a cylinder head capable of restraining residence of gas and air during forging while improving cooling efficiency of an exhaust collection part.SOLUTION: The water jacket structure comprises: plural combustion chamber peak parts 21; plural exhaust ports 23; an exhaust collection part 24 for collecting the plural exhaust ports 23; an upper exhausting water jacket 80 arranged on an upper side to the exhaust collection part 23; and a lower exhausting water jacket 90 arranged on a lower side to the exhaust collection part 24. The upper exhausting water jacket 80 and the lower exhausting water jacket 90 form flow passages independent from each other. The upper exhausting water jacket 80 has a protrusion part 81, and the lower exhausting water jacket has a protrusion part 91. The protrusion part 81 and the protrusion part 91 are spaced from each other by a predetermined interval in a cylinder axial line direction. A protrusion amount L1 of the protrusion part 81 is smaller than a protrusion part L2 of the protrusion part 91.

Description

  The present invention relates to a water jacket structure for a cylinder head, and more particularly to a water jacket structure for a cylinder head in which an exhaust collecting portion for collecting a plurality of exhaust ports is integrally formed.

  2. Description of the Related Art As a cylinder head, one in which an exhaust collecting portion that collects a plurality of exhaust ports extending from a plurality of combustion chambers is integrally formed is known. In such a cylinder head, an exhaust water jacket for cooling the exhaust port and the exhaust collecting portion is provided in addition to the combustion chamber water jacket for cooling the combustion chamber in order to sufficiently cool the exhaust collecting portion that is likely to become high temperature. It has been.

  For example, in Patent Document 1, an exhaust water jacket is provided on each of the upper and lower sides of the exhaust collecting portion, and between the side surface of the cylinder head provided with the exhaust opening of the exhaust collecting portion and the exhaust collecting portion, There is disclosed a water jacket structure of a cylinder head provided with a communicating portion that communicates the upper and lower exhaust water jackets.

  By the way, as a manufacturing method of a cylinder head, a method of manufacturing by casting using a core is common. In such a casting method, the resin binder forming the core is burned by the heat of the molten metal poured into the mold cavity, and gas is generated. It is known that casting defects will be caused if it is contained in the steel. Further, it is known that if air existing in a cavity before pouring is caught in a molten metal and contained in a cast product, a casting defect is caused. Therefore, it is desirable to discharge gas and air out of the mold as much as possible.

JP 2010-209749 A

  However, since the structure described in Patent Document 1 has a communication portion that communicates the upper and lower exhaust water jackets of the exhaust collecting portion, when the cylinder head is cast, the upper and lower exhaust portions are connected. There is an adverse effect that gas and air are likely to stay in a region surrounded by the core corresponding to the water jacket and the core corresponding to the communication portion.

  The present invention has been made in view of such problems, and provides a water jacket structure for a cylinder head capable of suppressing gas and air stagnation during casting while improving the cooling efficiency of the exhaust collecting portion. This is the issue.

A water jacket structure of a cylinder head according to the present invention includes a plurality of combustion chamber top portions formed on a bottom surface of the cylinder head, a plurality of exhaust ports communicating with each of the plurality of combustion chamber top portions, and an inside of the cylinder head. The exhaust ports that collect the plurality of exhaust ports and have an exhaust opening that opens on one side surface along the cylinder row direction of the cylinder head, and are disposed on the upper side in the cylinder axial direction with respect to the exhaust assembly, An upper exhaust water jacket that cools the exhaust collecting portion; and a lower exhaust water jacket that is disposed on the lower side in the cylinder axial direction with respect to the exhaust collecting portion and cools the exhaust collecting portion. The exhaust water jacket and the lower exhaust water jacket are independent from each other inside the cylinder head. The upper exhaust water jacket has an upper protrusion that protrudes toward the lower exhaust water jacket and is arranged to face the downstream side of the exhaust assembly. The lower exhaust water jacket has a lower protrusion that is disposed so as to protrude toward the upper exhaust water jacket and to face the downstream side of the exhaust assembly; The upper protrusion and the lower protrusion are provided to be spaced apart from each other by a predetermined distance in the cylinder axis direction, and the protrusion amount of the upper protrusion is smaller than the protrusion amount of the lower protrusion. And
Note that “up and down in the cylinder axis direction” means that the upper side is the upper side and the lower side is the lower side with respect to the cylinder orthogonal plane that is a plane orthogonal to the cylinder axis.

  According to the present invention, the upper protrusion and the lower protrusion are provided to be spaced apart from each other by a predetermined distance in the cylinder axis direction, and the protrusion amount of the upper protrusion is smaller than the protrusion amount of the lower protrusion. Therefore, when casting a cylinder head having such a structure, gas and air do not stay in the core portion corresponding to the upper protruding portion, and correspond to the core portion and lower protruding portion corresponding to the upper protruding portion. Then, the gas is discharged out of the region surrounded by the cores corresponding to the upper and lower exhaust water jackets through a gap formed between the core portions. Therefore, gas and air stagnation during casting can be suppressed.

Further, according to the present invention, since the downstream side portion of the exhaust collecting portion can be covered with the upper protruding portion and the lower protruding portion and the entire exhaust collecting pipe can be covered with the upper and lower exhaust water jackets, the exhaust collecting portion The cooling efficiency can be improved.
Furthermore, according to the present invention, since the protruding amount of the lower protruding portion is larger than the protruding amount of the upper protruding portion, for example, when the internal combustion engine is tilted and mounted on a vehicle, or when the internal combustion engine is inclined on a slope or the like. Even in this case, the lower exhaust water jacket can function as an air vent passage. Thereby, it becomes possible to suppress the occurrence of air accumulation in the lower exhaust water jacket, and the cooling efficiency of the exhaust collecting portion can be improved.

  The lower protrusion is provided on both sides of the exhaust opening, and the protruding end of the lower protrusion extends along the downstream side of the exhaust assembly from the exhaust opening. It is preferable that the structure is inclined so as to be positioned on the upper side in the cylinder axial direction as the distance increases.

  According to such a configuration, the protruding end of the lower protruding portion is inclined so as to be positioned on the upper side in the cylinder axial direction as it is separated from the exhaust opening along the downstream side portion of the exhaust collecting portion. When the air contained in the coolant in the lower exhaust water jacket passes through the lower protrusion, it is guided along the inclined surface of the lower protrusion and flows easily without stagnation. As a result, it is possible to suppress the occurrence of air accumulation in the lower protruding portion, and the cooling efficiency of the exhaust collecting portion can be improved.

  The upper protrusion is provided on both sides of the exhaust opening, and the protruding end of the upper protrusion is separated from the exhaust opening along the downstream side of the exhaust assembly. Accordingly, it is preferable to incline so as to be located on the lower side in the cylinder axial direction and then to be inclined so as to be located on the upper side in the cylinder axial direction.

  According to such a configuration, the protruding end of the upper protruding portion is inclined so as to be positioned on the lower side in the cylinder axial direction as being separated from the exhaust opening along the downstream side portion of the exhaust collecting portion, and then the cylinder. Since the cylinder head is inclined so as to be located on the upper side in the axial direction, gas and air are guided to the gap from the core portion corresponding to the inclined surface in which the protruding amount is suppressed when casting the cylinder head having such a structure. This makes it possible to suppress the retention of gas and air. In particular, gas and air bypass the core portion corresponding to the portion with the largest protrusion amount of the upper protrusion (the portion where the inclination direction changes), and are guided to the gap from the core portion corresponding to the inclined surface. It becomes easy to be.

  A water jacket structure of a cylinder head according to the present invention includes a plurality of combustion chamber top portions formed on a bottom surface of the cylinder head, a plurality of exhaust ports communicating with each of the plurality of combustion chamber top portions, and an inside of the cylinder head. The exhaust ports that collect the plurality of exhaust ports and have an exhaust opening that opens on one side surface along the cylinder row direction of the cylinder head, and are disposed on the upper side in the cylinder axial direction with respect to the exhaust assembly, An upper exhaust water jacket that cools the exhaust collecting portion; and a lower exhaust water jacket that is disposed on the lower side in the cylinder axial direction with respect to the exhaust collecting portion and cools the exhaust collecting portion. The exhaust water jacket and the lower exhaust water jacket are independent from each other inside the cylinder head. And a projecting portion disposed so as to oppose the downstream side portion of the exhaust collecting portion is provided only in the lower exhaust water jacket, and the projecting portion is disposed on the upper exhaust side. It protrudes toward the water jacket, and the upper exhaust water jacket and the protruding portion are provided at a predetermined distance from each other in the cylinder axis direction.

  According to the present invention, the upper exhaust water jacket and the projecting portion are provided to be spaced apart from each other by a predetermined distance in the cylinder axial direction, and are disposed to face the downstream side portion of the exhaust assembly portion. Is provided only in the lower exhaust water jacket, so that when the cylinder head having such a structure is cast, gas and air do not stay in the core corresponding to the upper exhaust water jacket, and the upper exhaust water jacket The gas passes through a gap formed between the core corresponding to the jacket and the core corresponding to the protruding portion, and is discharged out of the region surrounded by the cores corresponding to the upper and lower exhaust water jackets. Therefore, gas and air stagnation during casting can be suppressed.

Further, according to the present invention, the downstream side portion of the exhaust collecting portion can be covered with the protruding portion, and the entire exhaust collecting pipe can be covered with the upper and lower exhaust water jackets, so that the cooling efficiency of the exhaust collecting portion is improved. be able to.
Further, according to the present invention, since the protrusion is provided only on the lower exhaust water jacket, and the protrusion amount of the protrusion can be secured large, for example, when the internal combustion engine is tilted and mounted on a vehicle, or on a slope or the like, Even when the engine is inclined, the lower exhaust water jacket can function as an air vent passage. Thereby, it becomes possible to suppress the occurrence of air accumulation in the lower exhaust water jacket, and the cooling efficiency of the exhaust collecting portion can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the water jacket structure of the cylinder head which can suppress the stay of the gas and air at the time of casting can be provided, aiming at the improvement of the cooling efficiency of an exhaust_gas | exhaustion assembly part.

It is sectional drawing of the internal combustion engine which has the water jacket structure of the cylinder head which concerns on this embodiment. It is a perspective view of a cylinder head. It is the perspective view drawn through seeing through the exhaust gathering part inside a cylinder head, and a head side water jacket. It is the perspective view which decomposed | disassembled and showed the head side water jacket and the exhaust_gas | exhaustion gathering part up and down. FIG. 6 is a bottom view of an intake water jacket, a combustion chamber water jacket, and an upper exhaust water jacket. It is a bottom view of the water jacket for lower exhaust. It is the front view which looked at the head side water jacket and the exhaust gas collection part from the front. It is a partial expanded sectional view of FIG. It is a disassembled perspective view for demonstrating the flow of the cooling fluid from the block side water jacket to the water jacket for intake. It is a disassembled perspective view for demonstrating the flow of the cooling fluid from the block side water jacket to the lower water jacket for exhaust. It is the bottom view which overlapped and drew the head side water jacket and the block side water jacket on the gasket. It is a bottom view for demonstrating the flow of the cooling fluid of the water jacket for intake, the water jacket for combustion chambers, and the water jacket for upper side exhaust. It is a bottom view for demonstrating the flow of the cooling fluid of the water jacket for lower side exhaust. It is the elements on larger scale of the casting die apparatus in the site | part corresponding to FIG. 8, (a) is the state before filling a molten metal in a cavity, (b) is in the middle of filling a molten metal in a cavity. The state (c) shows a state where the molten metal is filled in the entire cavity.

  Embodiments of the present invention will be described in detail with reference to FIGS. In the description, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the direction will be described based on the front, rear, left, right, top and bottom in a state where the internal combustion engine E is installed in the vehicle, as shown in each drawing.

FIG. 1 is a cross-sectional view of an internal combustion engine having a water jacket structure for a cylinder head according to the present embodiment.
As shown in FIG. 1, an internal combustion engine E to which the present invention is applied includes a cylinder block 1 in which four cylinders 1 a (only one is shown in FIG. 1) are arranged in series, and are integrally provided. The cylinder head 2 is coupled to the upper end of the cylinder, the gasket 3 is installed between the cylinder block 1 and the cylinder head 2, and the head cover (not shown) is coupled to the upper end of the cylinder head 2. Equipped with an engine body.

The internal combustion engine E is a multi-cylinder internal combustion engine that includes four cylinders 1a, pistons 4 that are reciprocally fitted to the cylinders 1a, and crankshafts 6 that are connected to the pistons 4 via connecting rods 5. The vehicle is mounted in a horizontal arrangement in which the rotation center line of the crankshaft 6 is directed in the left-right direction. The internal combustion engine E is disposed with the intake side facing the rear of the vehicle and the exhaust side facing the front of the vehicle.
For each cylinder 1a, a combustion chamber 7 is formed between the piston 4 and the cylinder head 2 between the piston 4 and the cylinder head 2 in the cylinder axis direction that is parallel to the cylinder axis Lc of the cylinder 1a. Is done.
In the present embodiment, the internal combustion engine E is installed so that the cylinder axis Lc and the vertical axis direction (that is, the vertical direction) coincide with each other. However, the present invention is not limited to this, and for example, the cylinder axis The internal combustion engine E may be installed such that Lc is inclined with respect to the vertical axis direction.

  The cylinder block 1 includes a block-side water jacket 10 that serves as a coolant flow path for cooling the cylinder 1a, in addition to the cylinder 1a and the crankcase (not shown). The block-side water jacket 10 is a concave groove-like space that continuously surrounds the whole of the four cylinders 1a, and opens on the upper surface of the cylinder block 1 (see FIGS. 9 and 10). A coolant cooled by a radiator (not shown) is supplied to one end side of the block-side water jacket 10. The block-side water jacket 10 communicates with an intake water jacket 50 and a lower exhaust water jacket 90, which will be described later, through the through holes 32, 35 and the like of the gasket 3, and supplies coolant to both. ing. The block side water jacket 10 and the gasket 3 will be described in detail later.

  FIG. 2 is a perspective view of the cylinder head. FIG. 3 is a perspective view illustrating the exhaust collecting part and the head-side water jacket inside the cylinder head. In addition, in FIG. 3, the external shape of the cylinder head 2 is drawn with the virtual line (two-dot chain line).

  The cylinder head 2 is a metal member manufactured by casting using a core. As shown in FIGS. 1 to 3 (mainly FIG. 1), the cylinder head 2 includes four combustion chamber tops 21 (only one is shown in FIG. 1) constituting the top of the combustion chamber 7, and each combustion chamber 7. An intake port 22 for introducing air into the exhaust chamber, an exhaust port 23 for exhausting combustion gas from each combustion chamber 7, an exhaust collecting portion 24 for collecting a plurality of exhaust ports 23 inside the cylinder head 2, and for cooling them The head side water jacket 40 is mainly included. Further, the cylinder head 2 has a valve operating chamber 25 for accommodating a part of the valve operating mechanism (not shown) at the upper part thereof.

  The combustion chamber top 21 is a substantially conical recess provided on the bottom surface 2 a of the cylinder head 2. The intake port 22 communicates each combustion chamber top 21 with the rear surface 2b of the cylinder head 2. The exhaust port 23 communicates each combustion chamber top portion 21 and the exhaust collecting portion 24. Two intake ports 22 and two exhaust ports 23 are provided for each combustion chamber top 21. The intake port 22 and the exhaust port 23 are provided with an intake valve and an exhaust valve (not shown).

  As shown in FIG. 2, the exhaust collecting portion 24 has one opening 24 a that opens at a substantially central portion in the left-right direction of the front surface 2 c of the cylinder head 2. The exhaust collecting portion 24 is provided in a portion of the cylinder head 2 that projects forward from the cylinder block 1 (see FIG. 1). The valve operating chamber 25 is a concave space formed in the upper surface 2 d of the cylinder head 2. The valve operating chamber 25 accommodates a part of a valve operating mechanism such as a camshaft, a rocker arm, and a valve (not shown). Further, on the left side surface 2e of the cylinder head 2, outlet openings 63, 83, and 93 serving as coolant outlets of the head side water jacket 40 described later are formed. A water outlet (not shown) that distributes the coolant discharged from the outlet openings 63, 83, and 93 to the heater and the radiator is attached to the left side surface 2e of the cylinder head 2.

  In addition, the front surface 2c of the cylinder head 2 is connected to a core 100 (see FIG. 14) installed in the cavity 240 (see FIG. 14) during casting by a connecting portion that connects the base board supported by the mold. There are two support holes 2f to be formed, but these support holes 2f are closed with a cap or the like attached later.

  As shown in FIGS. 1 and 3, the head-side water jacket 40 is a space serving as a coolant flow path, and cools the intake water jacket 50 for cooling the intake port 22 and the combustion chamber top 21. A combustion chamber water jacket 60 and an exhaust water jacket 70 for cooling the exhaust port 23 and the exhaust collecting portion 24.

  As shown in FIG. 1, the intake water jacket 50 is provided below the intake port 22. The combustion chamber water jacket 60 is provided immediately above the combustion chamber top 21 and between the intake port 22 and the exhaust port 23. The exhaust water jacket 70 includes an upper exhaust water jacket 80 disposed above the exhaust port 23 and the exhaust collecting portion 24, and a lower exhaust water jacket disposed below the exhaust port 23 and the exhaust collecting portion 24. 90.

  The intake water jacket 50 communicates with the block-side water jacket 10 and also with the combustion chamber water jacket 60 (see the broken line in FIG. 1). The combustion chamber water jacket 60 communicates with the block-side water jacket 10 and also communicates with the upper exhaust water jacket 80. The lower exhaust water jacket 90 communicates with the block-side water jacket 10. The lower exhaust water jacket 90 does not communicate with the intake water jacket 50, the combustion chamber water jacket 60, and the upper exhaust water jacket 80. That is, the upper exhaust water jacket 80 and the lower exhaust water jacket 90 form independent flow paths inside the cylinder head 2.

  Next, regarding the detailed structure of the exhaust collecting portion 24 and the head side water jacket 40 (that is, the intake water jacket 50, the combustion chamber water jacket 60, the upper exhaust water jacket 80, and the lower exhaust water jacket 90), This will be described with reference to FIGS.

FIG. 4 is a perspective view showing the head-side water jacket and the exhaust collecting part in an exploded manner. FIG. 5 is a bottom view of an intake water jacket, a combustion chamber water jacket, and an upper exhaust water jacket. FIG. 6 is a bottom view of the lower exhaust water jacket. FIG. 7 is a front view of the head side water jacket and the exhaust collecting portion as viewed from the front.
Here, in FIG. 4 to FIG. 7, for convenience of explanation, the exhaust collecting portion 24 and the head-side water jacket 40 that are spaces are drawn as if they existed (that is, cores corresponding to them).

  As shown in FIG. 4, the exhaust collecting portion 24 includes a first collecting portion 24 b that collects two exhaust ports 23 communicating with each combustion chamber 7 into one, and four first collecting portions 24 b that are openings. And a second collection unit 24c that collects in one place immediately before 24a. The second collecting portion 24c and the opening 24a are provided at a substantially central portion in the left-right direction of the cylinder head 2. Of the four first collecting portions 24b, the right and left first collecting portions 24b are longer than the two first collecting portions 24b in the middle of the two. The front side surface of the right and left first collecting portions 24b is a protrusion 81 of an upper exhaust water jacket 80 and a protrusion 91 of a lower exhaust water jacket 90 (see FIGS. 1, 4 to 6). ) Constitutes the downstream side portion 24d of the exhaust collecting portion 24 to be cooled. The downstream side portion 24d is inclined so as to be positioned on the front side as it approaches the central opening portion 24a from the exhaust ports 23 at both left and right ends in plan view.

  As shown in FIGS. 4 and 5 (mainly FIG. 5), the intake water jacket 50 is a portion for cooling the intake port 22 (see FIG. 1), and traverses the lower side of each intake port 22 in the left-right direction. It is extended while meandering. The intake water jacket 50 has eight intake-side inflow portions 51 that open to the bottom surface 2 a of the cylinder head 2 (see FIG. 2) below each intake port 22. The intake water jacket 50 and the combustion chamber water jacket 60 are located at positions corresponding to each other between the adjacent cylinders 1a (hereinafter sometimes referred to as “between cylinder shafts”) and outside the left and right cylinders 1a. It has the communication part 52 which connects. Below the communication portion 52 between the three cylinder shafts, an inter-axis inflow portion 53 that opens to the bottom surface 2a of the cylinder head 2 is provided.

  The combustion chamber water jacket 60 is a portion that cools the combustion chamber top 21 (see FIG. 1), and extends above the combustion chamber top 21 in the left-right direction. The combustion chamber water jacket 60 is formed wider in the front-rear direction than the intake water jacket 50 and surrounds a spark plug (not shown). The combustion chamber water jacket 60 has two combustion chamber side inflow portions 61 that open to the bottom surface 2a of the cylinder head 2 at the right end (see FIG. 7). In addition, the combustion chamber water jacket 60 has a communication portion 62 that communicates with the upper exhaust water jacket 80 at a position corresponding to between the exhaust ports 23 (see FIG. 1). Further, the combustion chamber water jacket 60 has an outlet opening 63 that opens to the left side surface 2e of the cylinder head 2 and serves as an outlet for the coolant at the left end (see FIG. 2). The outlet opening 63 is formed wider in the front-rear direction than the combustion chamber water jacket 60 and extends to the front side.

  As shown in FIGS. 4, 5, and 7 (mainly FIG. 5), the upper exhaust water jacket 80 is provided so as to cover the upper sides of the exhaust ports 23 and the exhaust collecting portion 24. The upper exhaust water jacket 80 has a wider width in the front-rear direction and a smaller thickness in the vertical direction than the intake water jacket 50 and the combustion chamber water jacket 60 (FIG. 1). reference). The upper exhaust water jacket 80 has a projecting portion 81 projecting downward from the front end portion (see FIG. 1). The protruding portion 81 is disposed so as to face the downstream side portion 24 d of the exhaust collecting portion 24. In addition, the protrusion part 81 is not provided in the part 82 corresponding to the opening part 24a of the exhaust gas collection part 24 among the front side edge parts of the upper water jacket 80 for exhaust. The upper exhaust water jacket 80 has, at the left end, an outlet opening 83 that opens to the left side surface 2e of the cylinder head 2 and serves as a coolant outlet (see FIG. 2).

  Incidentally, with reference to FIG. 5, the intake port 22 is installed in a portion 55 between the intake water jacket 50 and the combustion chamber water jacket 60. In addition, a spark plug (not shown) is installed in a portion 65 of the combustion chamber water jacket 60 corresponding to the center position of the cylinder 1a. Further, an exhaust valve (not shown) is installed in a portion 67 between the combustion chamber water jacket 60 and the upper exhaust water jacket 80.

  As shown in FIGS. 4, 6, and 7 (mainly FIG. 6), the lower exhaust water jacket 90 is provided so as to cover the lower sides of the exhaust ports 23 and the exhaust collecting portion 24. The lower exhaust water jacket 90 is formed flat so as to have the same thickness as the upper exhaust water jacket 80 (see FIG. 1). The lower exhaust water jacket 90 has a protrusion 91 that protrudes upward from the front end (see FIG. 1). The protruding portion 91 is disposed so as to face the downstream side portion 24 d of the exhaust collecting portion 24. In addition, the protrusion 91 is not provided in the part 92 corresponding to the opening part 24a of the exhaust gas collection part 24 among the front edge parts of the lower exhaust water jacket 90. The lower exhaust water jacket 90 has an outlet opening 93 that opens to the left side surface 2e of the cylinder head 2 and serves as an outlet for cooling liquid at the left end (see FIG. 2). The lower exhaust water jacket 90 has eight exhaust-side inflow portions 94 that open to the bottom surface 2a of the cylinder head 2 at positions corresponding to the lower ends of the exhaust ports 23 at the rear end. . Thus, since the exhaust-side inflow portion 94 is provided immediately below the exhaust port 23, the exhaust port 23 can be efficiently cooled. An additional inflow portion 95 is provided between the two exhaust side inflow portions 94 on the side farthest from the outlet opening 93 (that is, the upstream side).

Here, the protrusion 81 of the upper exhaust water jacket 80 and the protrusion 91 of the lower exhaust water jacket 90 will be described in detail with reference to FIGS. FIG. 8 is a partially enlarged sectional view of FIG.
As shown in FIG. 8, the protruding portion (upper protruding portion) 81 and the protruding portion (lower protruding portion) 91 are provided at a predetermined distance from each other in the cylinder axis direction. The protruding amount L1 of the protruding portion 81 is formed smaller than the protruding amount L2 of the protruding portion 91. In other words, the center line C1 along the cylinder axis direction passing through the cylinder axial direction center of the protruding end of the protruding portion 81 and the protruding end of the protruding portion 91 is the cylinder axis passing through the cylinder axial direction center of the exhaust collecting portion 24. It is set to be positioned above the center line C2 orthogonal to the direction. As shown in FIG. 7, the protrusions 81 and 91 are provided on both the left and right sides with an opening (exhaust opening) 24a interposed therebetween.

  A first inclined surface 81 a and a second inclined surface 81 b are formed at the protruding end of the protruding portion 81. The first inclined surface 81a is inclined so as to be located on the lower side in the cylinder axial direction as it is separated from the opening 24a along the downstream side portion 24d of the exhaust collecting portion 24. The second inclined surface 81b is inclined so as to be located on the upper side in the cylinder axial direction as it is separated from the opening 24a along the downstream side portion 24d of the exhaust collecting portion 24 continuously from the first inclined surface 81a. . On the other hand, a third inclined surface 91 a and a fourth inclined surface 91 b are formed at the protruding end of the protruding portion 91. The third inclined surface 91a is inclined so as to be located on the upper side in the cylinder axial direction as it is separated from the opening 24a along the downstream side portion 24d of the exhaust collecting portion 24. The fourth inclined surface 91b is inclined so as to be positioned on the upper side in the cylinder axial direction as it is separated from the opening 24a along the downstream side portion 24d of the exhaust collecting portion 24 continuously from the third inclined surface 91a. . The fourth inclined surface 91b is inclined more gently than the third inclined surface 91a. The protrusion 81 is provided on the upper side in the cylinder axial direction of the third inclined surface 91a and the fourth inclined surface 91b. Incidentally, the air contained in the cooling liquid tends to stay at the highest portion of the protrusion 91, but in this embodiment, the inclination is such that the protrusion end of the protrusion 91 gradually decreases toward the exhaust collecting portion 24. Therefore, the air is guided along the third inclined surface 91a and the fourth inclined surface 91b and easily flows without stagnation.

FIG. 9 is an exploded perspective view for explaining the flow of the coolant from the block-side water jacket to the intake water jacket. FIG. 10 is an exploded perspective view for explaining the flow of the coolant from the block-side water jacket to the lower exhaust water jacket. FIG. 11 is a bottom view in which a head side water jacket and a block side water jacket are overlapped with a bottom view of the gasket.
In FIGS. 9 and 10, for convenience of explanation, portions of the head-side water jacket 40 other than the inflow portion are drawn with phantom lines (two-dot chain lines). In FIG. 11, the gasket 3 is hatched with dots, and the opening of the block-side water jacket 10 is drawn with a virtual line (thick broken line).

  As shown in FIGS. 9, 10, and 11, the block-side water jacket 10 is formed so as to entirely surround the four cylinders 1a. The block-side water jacket 10 has a coolant introduction portion 11 that is wider than other portions on the front side of the rightmost cylinder 1a. A partition member 11a is inserted into the introduction portion 11, and regulates the direction in which the coolant flows. In the present embodiment, the coolant pipe P is connected to the left side of the partition member 11a of the introduction portion 11. Further, the block-side water jacket 10 has a constricted portion 12 at a portion corresponding to between the cylinders 1a (between the cylinder shafts). In addition, a concave groove-shaped inter-axis slit 13 is formed between the cylinder shafts so that the front and rear constricted portions 12 communicate with each other.

  As shown in FIGS. 9, 10, and 11 (mainly FIG. 11), the gasket 3 is a metal plate-like member that seals the coupling portion between the cylinder block 1 and the cylinder head 2. The gasket 3 has four cylinder openings 31 corresponding to the four cylinders 1 a of the cylinder block 1. The gasket 3 includes an intake-side through hole 32 and an inter-axis through hole 33 formed at positions corresponding to the intake-side inflow portion 51 and the inter-axis inflow portion 53 of the intake water jacket 50, and a combustion chamber water jacket 60. The combustion chamber side through hole 34 formed at a position corresponding to the combustion chamber side inflow portion 61 and the exhaust gas formed at positions corresponding to the exhaust side inflow portion 94 and the additional inflow portion 95 of the lower exhaust water jacket 90. A side through hole 35 and an additional through hole 36 are provided. These intake side through hole 32, inter-shaft through hole 33, combustion chamber side through hole 34, exhaust side through hole 35 and additional through hole 36 are all formed at positions corresponding to the opening of block side water jacket 10. Yes. The intake-side through-hole 32 and the exhaust-side through-hole 35 have some exceptions, but the hole located on the right side (the hole far from the outlet openings 63, 83, 93) is formed with a large diameter. ing. In particular, the combustion chamber side through hole 34 is formed to have a larger diameter than the other through holes 32, 33, 35, and 36. Thereby, the vertical flow described later is easily formed.

Next, the flow of the coolant in the block-side water jacket 10 and the head-side water jacket 40 will be described with reference to FIGS. 9 to 13.
FIG. 12 is a bottom view for explaining the flow of the coolant in the intake water jacket, the combustion chamber water jacket, and the upper exhaust water jacket. FIG. 13 is a bottom view for explaining the flow of the coolant in the lower exhaust water jacket.

  As shown in FIGS. 9 and 10, the coolant (arrow Y1) that has flowed into the introduction part 11 from the coolant pipe P flows in the left direction along the block-side water jacket 10 (arrow Y2). Then, after making a U-turn at the left end (arrow Y3), the rear side of the cylinder 1a flows rightward along the block-side water jacket 10 (arrow Y4), and reaches the right end (arrow Y5). Further, the coolant flows from the front constricted portion 12 toward the rear constricted portion 12 through the inter-axis slit 13 (arrow Y6).

  As shown in FIG. 10, a part of the coolant (arrow Y <b> 2) that flows in the left direction along the block-side water jacket 10 in the front side of the cylinder 1 a is formed by the exhaust-side through hole 35 and the additional through-hole formed in the gasket 3. 36 and flows into the inside of the lower exhaust water jacket 90 from the exhaust side inflow portion 94 and the additional inflow portion 95 (arrow Y7). That is, the flow of the coolant in the present embodiment is a so-called exhaust-preceding flow in which the coolant flows into the lower exhaust water jacket 90 prior to the intake water jacket 50. As a result, the exhaust port 23 and the exhaust collecting portion 24 can be efficiently cooled.

  Further, as shown in FIG. 9, a part of the coolant (arrow Y <b> 4) flowing in the right direction on the rear side of the cylinder 1 a along the block side water jacket 10 passes through the intake side through hole 32 formed in the gasket 3. Then, the air flows into the intake water jacket 50 from the intake-side inflow portion 51 (arrow Y8a). In addition, the coolant (arrow Y6) passing through the inter-axis slit 13 merges with the constricted portion 12 on the rear side, passes through the inter-axis through hole 33 formed in the gasket 3, and passes through the inter-axis inflow portion 53 for intake. It flows into the inside of the water jacket 50 (arrow Y8b). Further, the coolant (arrow Y5) that has reached the right end portion of the block-side water jacket 10 passes through the combustion chamber-side through hole 34 formed in the gasket 3 and from the combustion chamber-side inflow portion 61 to the combustion chamber water jacket 60. (Arrow Y9).

  As shown in FIG. 12, the coolant that has flowed from the combustion chamber side inflow portion 61 into the right end portion of the combustion chamber water jacket 60 flows from the right to the left toward the outlet opening 63 at the left end portion (arrow Y10). This flow (arrow Y10) forms a flow (so-called vertical flow) along the arrangement direction Lb (see FIGS. 9 and 10) of the cylinder 1a (that is, the combustion chamber top portion 21) in the water jacket 60 for the combustion chamber. Further, the coolant that has flowed into the intake water jacket 50 from the intake-side inflow portion 51 and the inter-shaft inflow portion 53 flows into the combustion chamber water jacket 60 through the communication portion 52 (arrow Y11). Join the longitudinal flow. The coolant (arrow Y10) that has flowed from right to left in the combustion chamber water jacket 60 flows out of the cylinder head 2 through the outlet opening 63.

  A part of the coolant flowing through the combustion chamber water jacket 60 flows into the upper exhaust water jacket 80 through the communication portion 62. The flow (arrow Y12) flowing in from each communication portion 62 merges at the front end side of the upper exhaust water jacket 80 and follows the arrangement direction Lb (see FIGS. 9 and 10) of the cylinder 1a (that is, the combustion chamber top portion 21). A flow (so-called longitudinal flow) is formed (arrow Y13). The right front portion 80a of the upper exhaust water jacket 80 is inclined so as to be positioned on the front side as it approaches the outlet opening 83, so that the coolant flowing in from the right communication portion 62 toward the front It is guided by the right front part 80 a of the exhaust water jacket 80 and flows easily toward the outlet opening 83. The coolant flowing from the right to the left in the upper exhaust water jacket 80 flows out of the cylinder head 2 through the outlet opening 83.

  As shown in FIG. 13, the coolant (arrow Y <b> 14) that has flowed into the lower exhaust water jacket 90 from the exhaust side inflow portion 94 flows forward and joins at the front end side of the lower exhaust water jacket 90. Then, a flow (so-called vertical flow) is formed along the arrangement direction Lb (see FIGS. 9 and 10) of the cylinder 1a (that is, the combustion chamber top portion 21) (arrow Y15). Note that the right front portion 90a of the lower exhaust water jacket 90 is inclined so as to be positioned on the front side as it approaches the outlet opening 93, so that it faces forward from the right exhaust side inflow portion 94 and the additional inflow portion 95. The coolant that has flowed in is guided to the right front portion 90 a of the lower exhaust water jacket 90 and easily flows toward the outlet opening 93. The coolant (arrow Y15) that has flowed from right to left in the lower exhaust water jacket 90 flows out of the cylinder head 2 through the outlet opening 93.

Next, the casting mold apparatus 200 and the core 100 will be described with reference to FIGS. 4 and 14.
FIG. 14 is a partially enlarged cross-sectional view of the casting mold apparatus at a portion corresponding to FIG. 8, (a) is a state before the molten metal is filled in the cavity, and (b) is a molten metal filled in the cavity. The state (c) in the middle of being carried out shows a state where the molten metal is filled in the entire cavity.

  As shown in FIG. 14, the casting mold apparatus 200 is an apparatus for casting the cylinder head 2, and includes an upper mold 210 that is movable along the vertical direction, and a lower mold 220 that is a fixed mold. , And four lateral molds 230 (only one is shown in FIG. 14) provided to be movable along the horizontal direction. The cavity 240 is formed by clamping the plurality of molds.

  The lower mold 220 is provided with a gate (not shown) for filling the melt into the cavity 240 from below. The upper mold 210 and the side mold 230 are provided with a discharge hole (not shown) that communicates the inside and outside of the mold. The discharge hole has a function of discharging gas generated by the contact between the core 100 and the molten metal and air existing in the cavity 240 before pouring out of the mold. The exhaust hole is provided above the core 100.

  The core 100 is a sand mold for forming the exhaust collecting portion 24 and the head side water jacket 40. The core 100 is formed by using foundry sand as a main raw material and mixing a binder containing resin as a main component therein. As shown in FIGS. 4 and 14, the core 100 includes a second water jacket core 120, an exhaust core 130, and a first water jacket core 110. The 200 cavities 240 are installed in this order from the bottom. That is, since the installation of the core 100 is completed simply by arranging the three cores 100 so as to be stacked in order from the bottom, complication of installation work of the core 100 is suppressed.

  As shown in FIG. 4, the first water jacket core 110 is for forming an intake water jacket 50, a combustion chamber water jacket 60, and an upper exhaust water jacket 80. As shown in FIG. 14, a protruding portion core portion 110 a for forming the protruding portion 81 is integrally formed at the end portion of the first water jacket core 110.

The second water jacket core 120 is for forming a lower exhaust water jacket 90, as shown in FIG. As shown in FIG. 14, a protruding portion core portion 120 a for forming the protruding portion 91 is integrally formed at the end of the second water jacket core 120. A predetermined gap G is provided between the protruding portion core portion 110a and the protruding portion core portion 120a. The protruding amount of the protruding portion core portion 110a is smaller than the protruding amount of the protruding portion core portion 120a.
As shown in FIG. 4, the exhaust core 130 is for forming the exhaust collecting portion 24.

  Next, effects of the casting mold apparatus 200 and the core 100 will be described with reference to FIG.

  As shown in FIGS. 14A to 14C, the molten metal poured from a not shown gate of the lower mold 220 is filled into the cavity 240 from below. In this case, when the molten metal wraps around the core 100 disposed in the cavity 240 and comes into contact with the core 100, the resin binder is burned and gas is generated. The gas is driven to the inner wall side of the upper mold 210 and the side mold 230 by the molten metal tip together with the air in the cavity 240.

  At this time, in this embodiment, as shown in FIG. 14 (b), a predetermined gap G is provided between the protruding portion core portion 110a and the protruding portion core portion 120a, and the protruding portion is protruded. Since the protruding amount of the core portion 110a for the portion is smaller than the protruding amount of the core portion 120a for the protruding portion, the gas and air do not stay in the protruding portion core portion 110a and pass through the first gap G. It is discharged out of the area surrounded by the water jacket core 110 and the second water jacket core 120 (see the arrow in FIG. 14B).

  Subsequently, the gas and air discharged out of the area are discharged out of the mold through an exhaust hole (not shown). Then, after the molten metal has cooled and solidified, the casting mold apparatus 200 is opened and the core 100 is removed (collapsed), whereby the cylinder head 2 is formed.

  As described above, according to the water jacket structure of the cylinder head according to the present embodiment, the protrusion 81 of the upper exhaust water jacket 80 and the protrusion 91 of the lower exhaust water jacket 90 are predetermined in the cylinder axis direction. The protrusions 81 are spaced apart and the protrusion amount L1 of the protrusion 81 is smaller than the protrusion amount L2 of the protrusion 91. Therefore, when the cylinder head 2 having such a structure is cast, the gas and air are supplied to the protrusion 81. Through the gap G formed between the projecting core part 110a and the projecting core part 120a corresponding to the projecting part 91 without staying in the projecting core part 110a corresponding to Surrounded by a first water jacket core 110 and a second water jacket core 120 corresponding to the exhaust water jackets 80 and 90 It is discharged to the outside the region. Therefore, gas and air stagnation during casting can be suppressed.

  Further, the upper exhaust water jacket 80 and the lower exhaust water jacket 90 have projecting portions 81 and 91 arranged so as to project toward the other side and to face the downstream side portion 24d of the exhaust collecting portion 24. Since the upper exhaust water jacket 80 and the lower exhaust water jacket 90 are flow paths independent of each other, the downstream side portion 24d of the exhaust assembly portion 24 can be covered with the projecting portions 81 and 91. The entire exhaust assembly 24 can be covered with the exhaust water jacket 70 to improve the cooling efficiency.

  In addition, since the protrusion amount L2 of the protrusion 91 is larger than the protrusion amount L1 of the protrusion 81, for example, even when the internal combustion engine E is tilted and mounted on a vehicle, or when the internal combustion engine E is inclined on a slope or the like. The lower exhaust water jacket 90 can function as an air vent passage. Accordingly, it is possible to suppress the occurrence of air accumulation in the lower exhaust water jacket 90, and the cooling efficiency of the exhaust collecting portion 24 can be improved.

Further, the projecting end of the projecting portion 91 includes a third inclined surface 91a and a third inclined surface 91a which are inclined so as to be positioned on the upper side in the cylinder axial direction as they are separated from the opening 24a along the downstream side portion 24d of the exhaust collecting portion 24. Since the four inclined surfaces 91b are formed, the air contained in the coolant in the lower exhaust water jacket 90 passes along the third inclined surface 91a and the fourth inclined surface 91b when passing through the protruding portion 91. It will be easy to flow without itching. As a result, it is possible to suppress the occurrence of air accumulation in the projecting portion 91, and the cooling efficiency of the exhaust collecting portion 24 can be improved.
On the other hand, when the third inclined surface 91a and the fourth inclined surface 91b are formed at the protruding end of the protruding portion 91, the area covering the exhaust collecting portion 24 is reduced, but in the present embodiment, the third inclined surface of the protruding portion 91 is reduced. Since the projecting portion 81 of the upper exhaust water jacket 80 is provided on the upper side of the cylinder axis direction of the 91a and the fourth inclined surface 91b, the projecting portion 81 reduces the reduction in the covering area (cooling area) of the exhaust collecting portion 24. Can do.
Further, when the protrusion 81 is provided in the upper exhaust water jacket 80, gas or air tends to stay in the protrusion core portion 110a corresponding to the protrusion 81 when the cylinder head 2 is cast. Then, the protruding amount L1 of the protruding portion 81 is made smaller than the protruding amount L2 of the protruding portion 91, and further, at the protruding end of the protruding portion 81, from the opening 24a to the downstream side portion 24d of the exhaust collecting portion 24. Since the first inclined surface 81a that inclines so as to be located on the lower side in the cylinder axial direction and the second inclined surface 81b that is inclined so as to be located on the upper side in the cylinder axial direction as it is separated along the line is formed. Gas and air can be guided to the gap G from the first water jacket core 110 corresponding to the first inclined surface 81a and the second inclined surface 81b. The residence can be suppressed.
In particular, the gas and the air bypass the first water jacket core 110 corresponding to the portion with the largest protrusion amount of the protrusion 81 (the portion where the inclination direction changes), and the first inclined surface 81a and the first The first water jacket core 110 corresponding to the two inclined surfaces 81b is easily guided to the gap G.

  The water jacket structure of the cylinder head according to the present embodiment has been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and does not depart from the spirit of the present invention. Needless to say, it can be changed as appropriate.

  For example, in the present embodiment, the combustion chamber water jacket 60 is configured to communicate with the upper exhaust water jacket 80, but the present invention is not limited to this, and the upper exhaust water jacket 80 and the lower exhaust water jacket 80 are connected to the lower exhaust water jacket 80. The combustion chamber water jacket 60 may be configured to communicate with the lower exhaust water jacket 90 as long as the side exhaust water jacket 90 forms an independent flow path. Incidentally, if the combustion chamber water jacket 60 is configured to communicate with the upper exhaust water jacket 80, the vertical width of the communication portion 62 can be increased, so the first water shown in FIG. The rigidity of the jacket core 110 can be increased.

  In this embodiment, the protrusions 81 and 91 are provided on both the upper exhaust water jacket 80 and the lower exhaust water jacket 90. However, the present invention is not limited to this, and the lower exhaust is not limited thereto. The protrusion 91 may be provided only in the water jacket 90, and the protrusion 81 may not be provided in the upper exhaust water jacket 80. Even in such a configuration, when the cylinder head 2 is cast, the gas and the air do not stay in the first water jacket core 110 corresponding to the upper exhaust water jacket 80 and protrude from the first water jacket core 110. The first water jacket core 110 and the second water jacket corresponding to the upper and lower exhaust water jackets 80 and 90 through the gap G formed between the projecting core portions 120a corresponding to the portion 91. It is discharged out of the area surrounded by the core 120. Therefore, gas and air stagnation during casting can be suppressed. Further, the downstream side portion 24 d of the exhaust collecting portion 24 can be cooled while separating the upper exhaust water jacket 80 and the lower exhaust water jacket 90. Further, since the protrusion 91 is provided only in the lower exhaust water jacket 90 and the protrusion amount L2 of the protrusion 91 can be secured large, for example, when the internal combustion engine E is tilted and mounted on a vehicle, the internal combustion engine on a slope or the like Even when E is inclined, the lower exhaust water jacket 90 can function as an air vent passage. Accordingly, it is possible to suppress the occurrence of air accumulation in the lower exhaust water jacket 90, and the cooling efficiency of the exhaust collecting portion 24 can be improved.

  Further, in the present embodiment, the opening 24a of the exhaust collecting portion 24 is formed at a position that is substantially the center in the left-right direction of the cylinder head 2, but the opening of the exhaust collecting portion 24 is located at a position offset to either the left or right. 24a may be formed.

  Further, the present invention has been described taking the in-line four-cylinder internal combustion engine E as an example, but the present invention is not limited to this, and is applicable to the internal combustion engine E having other cylinder numbers such as two cylinders and three cylinders. It is also possible to apply to a V-type internal combustion engine E or the like. Further, the present invention is not limited to the internal combustion engine E of an automobile, and it is needless to say that the present invention can be applied to other internal combustion engines E such as ships and general-purpose machines.

DESCRIPTION OF SYMBOLS 1 Cylinder block 1a Cylinder 2 Cylinder head 21 Combustion chamber top part 22 Intake port 23 Exhaust port 24 Exhaust collecting part 24a Opening (exhaust opening)
24d Downstream side portion 3 Gasket 10 Block side water jacket 40 Head side water jacket 50 Intake water jacket 60 Combustion chamber water jacket 70 Exhaust water jacket 80 Upper exhaust water jacket 81 Projection (upper projection)
81a 1st inclined surface 81b 2nd inclined surface 90 Water jacket for lower side exhaust 91 Protruding part (lower protruding part)
91a Third inclined surface 91b Fourth inclined surface L1, L2 Projection amount E Internal combustion engine Lc Cylinder axis

Claims (4)

A plurality of combustion chamber tops formed on the bottom surface of the cylinder head;
A plurality of exhaust ports communicating with each of the plurality of combustion chamber tops;
An exhaust collecting part having an exhaust opening that gathers the plurality of exhaust ports inside the cylinder head and opens on one side surface along a cylinder row direction of the cylinder head;
An upper exhaust water jacket that is disposed on the upper side in the cylinder axial direction with respect to the exhaust collecting portion and cools the exhaust collecting portion;
A lower exhaust water jacket that is disposed on the lower side in the cylinder axial direction with respect to the exhaust collecting portion and cools the exhaust collecting portion,
The upper exhaust water jacket and the lower exhaust water jacket form mutually independent flow paths inside the cylinder head,
The upper exhaust water jacket has an upper protrusion that is arranged to protrude toward the lower exhaust water jacket and to face the downstream side of the exhaust assembly,
The lower exhaust water jacket has a lower projecting portion disposed so as to project toward the upper exhaust water jacket and to face the downstream side portion of the exhaust assembly portion.
The upper projecting portion and the lower projecting portion are provided at a predetermined distance from each other in the cylinder axial direction,
The water jacket structure of a cylinder head, wherein a protruding amount of the upper protruding portion is smaller than a protruding amount of the lower protruding portion. The lower protrusions are provided on both sides of the exhaust opening,
The projecting end of the lower projecting portion is inclined so as to be positioned on the upper side in the cylinder axial direction as it is separated from the exhaust opening along the downstream side portion of the exhaust collecting portion. Item 8. A water jacket structure for a cylinder head according to Item 1. The upper protrusions are provided on both sides with the exhaust opening interposed therebetween,
The protruding end of the upper protruding portion is inclined so as to be positioned on the lower side in the cylinder axial direction as being separated from the exhaust opening along the downstream side portion of the exhaust collecting portion, and then on the upper side in the cylinder axial direction. The water jacket structure for a cylinder head according to claim 1 or 2, wherein the water jacket structure is inclined so as to be positioned. A plurality of combustion chamber tops formed on the bottom surface of the cylinder head;
A plurality of exhaust ports communicating with each of the plurality of combustion chamber tops;
An exhaust collecting part having an exhaust opening that gathers the plurality of exhaust ports inside the cylinder head and opens on one side surface along a cylinder row direction of the cylinder head;
An upper exhaust water jacket that is disposed on the upper side in the cylinder axial direction with respect to the exhaust collecting portion and cools the exhaust collecting portion;
A lower exhaust water jacket that is disposed on the lower side in the cylinder axial direction with respect to the exhaust collecting portion and cools the exhaust collecting portion,
The upper exhaust water jacket and the lower exhaust water jacket form mutually independent flow paths inside the cylinder head,
A protrusion disposed so as to face the downstream side portion of the exhaust collecting portion is provided only in the lower exhaust water jacket,
The protruding portion protrudes toward the upper exhaust water jacket,
The water jacket structure for a cylinder head, wherein the upper exhaust water jacket and the projecting portion are spaced apart from each other in a cylinder axial direction.

Images