JP2014084740A - 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 reducing air remaining in a lower exhausting water jacket.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 exhausting collection part 24; and a lower exhausting water jacket 90 arranged on a lower side to the exhaust collection part 24. The lower exhausting water jacket has a protrusion part 91. An air vent passage R for exhausting air to the outside of the lower exhausting water jacket 90 is provided at an upper portion of the protrusion part 91 in a cylinder axial line direction.

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, Patent Document 1 discloses a water jacket structure of a cylinder head in which exhaust water jackets are provided on the upper side and the lower side of an exhaust collecting portion, respectively.

Japanese Patent No. 4329774

  By the way, if air stays in the lower exhaust water jacket, the portion of the cylinder head that is in contact with the air is less likely to be cooled, which may reduce the cooling efficiency of the exhaust assembly. For this reason, there has been a demand to reduce the amount of air staying in the lower exhaust water jacket as much as possible.

  This invention is made in view of such a point, and makes it a subject to provide the water jacket structure of the cylinder head which can reduce the air which retains in the water jacket for lower exhaust.

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. An exhaust collecting portion that collects the plurality of exhaust ports, an upper exhaust water jacket that is disposed above the exhaust collecting portion in the cylinder axial direction and cools the exhaust collecting portion, and the exhaust collecting portion A lower exhaust water jacket that is disposed on the lower side in the cylinder axial direction and that cools the exhaust collecting portion, and the lower exhaust water jacket projects toward the upper exhaust water jacket. It has a protrusion arranged so as to face the downstream side part of the collecting part, and the cylinder axis line of the protrusions The upper portion of the direction, characterized in that the air vent means for discharging air to the outside of the lower exhaust water jacket is provided.
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 portion in the cylinder axial direction of the projecting portion of the lower exhaust water jacket is provided with air venting means for exhausting air out of the lower exhaust water jacket. When the air in the exhaust water jacket flows through the protrusion, it is discharged to the outside through the air venting means. Thereby, it is possible to reduce the air staying in the lower exhaust water jacket, and the cooling efficiency of the exhaust collecting portion can be improved.

  The air venting means is integrally formed with a lower core for forming the lower exhaust water jacket during casting of the cylinder head, and holds the lower core in a predetermined position of the mold. It is preferable that the lower core holding means be formed.

  According to such a configuration, the air venting means is integrally formed with the lower core for forming the lower exhaust water jacket during casting of the cylinder head, and the lower core is disposed at a predetermined position of the mold. Therefore, the air venting means can be formed by using the lower core holding means necessary for casting the cylinder head. Accordingly, it is not necessary to separately form the air venting means by machining or the like, so that the work of forming the air venting means becomes easy.

  Further, it is preferable that the upper exhaust water jacket and the lower exhaust water jacket form an independent flow path inside the cylinder head.

  According to such a configuration, the upper exhaust water jacket and the lower exhaust water jacket form independent flow paths inside the cylinder head, so that the cooling water is forcibly deflected inside the cylinder head. Therefore, it is not necessary to branch off the coolant, and the flow of the coolant can be separated from each other to reduce the flow velocity and prevent the coolant from staying (stagnation). Further, since the decrease in the flow rate and the occurrence of the coolant staying portion (stagnation portion) are suppressed, the flow rate of the coolant flowing inside the exhaust water jacket is increased so that the exhaust collecting portion can be efficiently used with a small amount of coolant. Can be cooled. In addition, since it is not necessary to form a communication path that connects the upper and lower exhaust water jackets, it is easy to form the exhaust water jacket. Further, when the upper and lower exhaust water jackets form mutually independent flow paths, the air in the lower exhaust water jacket cannot be guided to the upper exhaust water jacket, and the air in the lower exhaust water jacket However, in the present invention, the air retention can be reduced by the air venting means, so that the above-described adverse effects can be eliminated.

  The air venting means is integrally formed with an upper core for forming the upper exhaust water jacket during casting of the cylinder head, and holds the upper core at a predetermined position of the mold. It is preferable that the structure is formed by a core holding means and the lower core holding means superimposed on the upper core holding means.

  According to such a configuration, the air venting means is integrally formed with the upper core for forming the upper exhaust water jacket during casting of the cylinder head, and holds the upper core in a predetermined position of the mold. Since it is formed by the upper core holding means and the lower core holding means superimposed on the upper core holding means, the lower core holding means and the upper core holding means required when casting the cylinder head are used. Thus, air bleeding means can be formed. Accordingly, it is not necessary to separately form the air venting means by machining or the like, so that the work of forming the air venting means becomes easy. Further, the air in the lower exhaust water jacket is discharged to the upper exhaust water jacket through the air venting means when flowing in the protrusion. Thereby, it is possible to reduce the air staying 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 reduce the air which retains in the water jacket for lower side exhaust can be provided.

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 the VIII-VIII line 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 a partial expanded sectional view of the casting die apparatus in the site | part corresponding to FIG. It is a partial expanded sectional view of the internal combustion engine which has the water jacket structure of the cylinder head which concerns on a modification. It is a partial expanded sectional view of the casting die apparatus in the site | part corresponding to FIG.

  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.

  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).

  Next, the protrusion 91 and the air vent passage R of the lower exhaust water jacket 90 will be described with reference to FIGS. 8 is a partially enlarged sectional view taken along line VIII-VIII in FIG.

  As shown in FIG. 7, the protrusions 91 are provided on both the left and right sides with an opening (exhaust opening) 24a interposed therebetween. A first inclined surface 91a, a second inclined surface 91b, a third inclined surface 91c, and a horizontal surface 91d are formed at the protruding end of the left protruding portion 91. The first inclined surface 91a 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. The second inclined surface 91b 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 91a. . The second inclined surface 91b is inclined more gently than the first inclined surface 91a. The third inclined surface 91c is inclined so as to be positioned 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 continuously from the second inclined surface 91b. Yes. The horizontal surface 91d extends substantially linearly continuously from the third inclined surface 91c.

  A fourth inclined surface 91e, a fifth inclined surface 91f, a sixth inclined surface 91g, and a seventh inclined surface 91h are formed at the protruding end of the right protruding portion 91. The fourth inclined surface 91e 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. The fifth inclined surface 91f 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 fourth inclined surface 91e. . The fifth inclined surface 91f is inclined more gently than the fourth inclined surface 91e. The sixth inclined surface 91g is inclined so as to be positioned 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 continuously from the fifth inclined surface 91f. Yes. The seventh inclined surface 91h 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 continuously from the sixth inclined surface 91g. Yes. The seventh inclined surface 91h is steeper than the sixth inclined surface 91g.

  As shown in FIG. 8, an air vent passage (air vent) for discharging the air in the lower exhaust water jacket 90 to the outside is provided between the front end of the protrusion 91 and the front surface 2c of the cylinder head 2. Means) R is extended in the front-rear direction. The air vent passage R communicates with an upper portion (upper half portion) in the cylinder axial direction of the projecting portion 91 and opens to the front surface 2 c of the cylinder head 2. The air guided into the air vent passage R is discharged to, for example, an expansion tank (reservation tank) through a pipe (not shown). In the present embodiment, as shown in FIG. 7, two air vent passages R are provided at a predetermined interval in the left-right direction. The left and right air vent passages R are provided at the highest portion (position) in the cylinder axis direction of the protrusion 91. That is, the left air vent passage R is provided at the boundary between the second inclined surface 91b and the third inclined surface 91c, which is the highest portion of the left protruding portion 91. The right air vent passage R is provided at the boundary between the fifth inclined surface 91f and the sixth inclined surface 91g, which is the highest portion of the right protruding portion 91. Since the air contained in the cooling liquid is likely to stay at the highest part of the protrusion 91, the air in the lower exhaust water jacket 90 is transferred to the outside by providing an air vent passage R in such a part. It can discharge suitably. Note that the air vent passage R may be provided at a place other than the highest part of the protrusion 91.

  Incidentally, reference numeral 2f shown in FIG. 2 denotes two support holes formed by the first baseboard 140 (see FIG. 4) that holds the first water jacket core 110 (see FIG. 4) in the mold during casting. The support hole 2f is closed with a cap or the like attached later.

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. Further, since an air vent passage R extends in the front-rear direction between the front end of the projecting portion 91 and the front surface 2c of the cylinder head 2, the coolant flowing in the lower exhaust water jacket 90 flows into the coolant. The contained air is discharged to the outside through the air vent passage R when flowing in the protrusion 91. 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.

  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 inner wall 230a of the side mold 230 is provided with a holding recess 230b for holding a second baseboard 150 and the like (described later) (only the holding recess 230b for holding the second baseboard 150 is shown in FIG. 14). ). 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. 4, a first baseboard 140 is integrally formed at the end of the first water jacket core 110. The first skirting board 140 includes a holding skirting board part 140a mounted in the holding recessed part 230b, a connecting skirting board part 140b for connecting the holding skirting board part 140a and the first water jacket core 110, have. In this case, the holding baseboard 140a is mounted in the holding recess 230b, whereby the first water jacket core 110 is positioned and held at a predetermined position in the cavity 240. Note that a support hole 2f is formed by the connecting baseboard 140b (see FIGS. 2 and 4).

  The second water jacket core (lower core) 120 is for forming a lower exhaust water jacket 90 as shown in FIG. As shown in FIGS. 4 and 14, a protruding portion core portion 120 a for forming the protruding portion 91 is integrally formed at the end portion of the second water jacket core 120. A second skirting board (lower core holding means) 150 is integrally formed at the end of the protruding portion core portion 120a. The second skirting board 150 includes a holding skirting board part 150a mounted in the holding recessed part 230b, and a connecting skirting board part 150b for connecting the holding skirting board part 150a and the protruding core part 120a. Have. In this case, the holding base board 150a is mounted in the holding recess 230b, whereby the second water jacket core 120 is positioned and held at a predetermined position in the cavity 240. The connecting baseboard part 150b is a part for forming the air vent passage R. In the present embodiment, as shown in FIG. 4, the first baseboard 140 formed on the first water jacket core 110 and the second baseboard 150 formed on the second water jacket core 120. Are provided with their positions shifted in the left-right direction.

  As shown in FIG. 4, the exhaust core 130 is for forming the exhaust collecting portion 24. A baseboard (not shown) is integrally formed at the front end of the exhaust core 130. In this case, when the baseboard is mounted in the holding recess 230 b of the side mold 230, the exhaust core 130 is positioned and held at a predetermined position in the cavity 240.

  In this state, the molten metal is filled into the cavity 240 from below through the gate (not shown) of the lower mold 220, and after the molten metal has cooled and solidified, the casting mold apparatus 200 is opened and the core 100 is removed (collapsed). By doing so, the cylinder head 2 is molded. The first water jacket core 110 forms an intake water jacket 50, a combustion chamber water jacket 60, and an upper exhaust water jacket 80. Further, the lower exhaust water jacket 90 is formed by the second water jacket core 120, and the exhaust collecting portion 24 is formed by the exhaust core 130. Further, an air vent passage R is formed by the connecting baseboard portion 150b.

As described above, according to the water jacket structure of the cylinder head according to the present embodiment, air is discharged out of the lower exhaust water jacket 90 to the upper portion of the protrusion 91 of the lower exhaust water jacket 90. Since the air vent passage R is provided, the air in the lower exhaust water jacket 90 is discharged to the outside through the air vent passage R when flowing through the protrusion 91. As a result, it is possible to reduce the air remaining in the lower exhaust water jacket 90 and to improve the cooling efficiency of the exhaust collecting portion 24.
In particular, the air vent passage R of the present embodiment is provided at the highest part of the protruding portion 91 in which air tends to stay, so that the air in the lower exhaust water jacket 90 is preferably discharged to the outside. Can do.

  The air vent passage R is integrally formed with the second water jacket core 120 for forming the lower exhaust water jacket 90 when the cylinder head 2 is cast. Since it is formed by the connecting baseboard portion 150b of the second baseboard 150 that is held at a predetermined position of the mold, the air vent passage R is formed by using the second baseboard 150 that is necessary when the cylinder head 2 is cast. be able to. Accordingly, it is not necessary to form the air vent passage R by machining or the like, so that the work of forming the air vent passage R is facilitated.

  Further, since the upper exhaust water jacket 80 and the lower exhaust water jacket 90 form mutually independent flow paths inside the cylinder head 2, the cooling water is forcibly deflected inside the cylinder head 2. Therefore, the flow of the cooling liquid can be separated from each other, and the decrease in the flow rate and the occurrence of the staying place (stagnation part) of the cooling liquid can be suppressed. Further, since the decrease in the flow rate and the occurrence of the coolant staying portion (stagnation portion) are suppressed, the flow rate of the coolant flowing inside the exhaust water jacket 70 is increased to efficiently collect the exhaust gas with a small amount of coolant. The part 24 can be cooled. Furthermore, since it is not necessary to form a communication path that connects the upper and lower exhaust water jackets 80, 90, the operation of forming the exhaust water jacket 70 is facilitated. Incidentally, when the upper and lower exhaust water jackets 80 and 90 form independent flow paths, the air in the lower exhaust water jacket 90 cannot be guided to the upper exhaust water jacket 80, and the lower exhaust water jacket 80 Although the harmful effect that the air is liable to stay in the water jacket 90 occurs, in the present embodiment, since the air retention can be reduced by the air vent passage R, the harmful effect can be eliminated.

  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 the present 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 upper exhaust water jacket 90 is provided. Only one of the water jacket 80 and the lower exhaust water jacket 90 may be provided with a protrusion. Even in such a configuration, the downstream side portion 24d of the exhaust collecting portion 24 can be cooled while the upper exhaust water jacket 80 and the lower exhaust water jacket 90 are separated.

  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.

  Next, a water jacket structure of a cylinder head according to a modification of the present invention will be described with reference to FIGS. 15 and 16. FIG. 15 is a partially enlarged sectional view of an internal combustion engine having a water jacket structure of a cylinder head according to a modified example, and FIG. 16 is a partially enlarged sectional view of a casting mold apparatus in a portion corresponding to FIG. In the description, the same elements as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.

As shown in FIG. 15, in the water jacket structure of the cylinder head according to the modified example, an air vent passage R is provided by connecting the front end of the upper exhaust water jacket 80 and the front end of the protrusion 91. The point is different from the above-described embodiment.
Further, as shown in FIG. 16, the water jacket structure of the cylinder head according to the modified example includes a first baseboard 140 formed integrally with the first water jacket core 110 and a second water jacket core 120. The point which formed the air vent path R with the 2nd baseboard 150 formed integrally differs from above-described embodiment.

  As shown in FIG. 16, the inner wall 230a of the modified lateral mold 230 is provided with a holding recess 230b for holding the first baseboard 140 and the second baseboard 150 integrally.

  In the present modification, the first baseboard 140 and the second baseboard 150 are provided so as to overlap in the vertical direction. In this case, the holding baseboard portions 140a and 150a are mounted in the holding recess 230b, whereby the first water jacket core 110 and the second water jacket core 120 are positioned at predetermined positions in the cavity 240. And are held together. The connecting baseboard portions 140b and 150b are portions for forming the air vent passage R.

  In the present modification, the first water jacket core 110 constitutes an upper core in the claims, and the second water jacket core 120 constitutes a lower core in the claims. Moreover, the 1st base board 140 comprises the upper side core holding means as used in a claim, and the 2nd base board 150 comprises the lower side core holding means as used in a claim.

  In this state, the molten metal is filled into the cavity 240 from below through the gate (not shown) of the lower mold 220, and after the molten metal has cooled and solidified, the casting mold apparatus 200 is opened and the core 100 is removed (collapsed). By doing so, the cylinder head 2 is molded. The first water jacket core 110 forms an intake water jacket 50, a combustion chamber water jacket 60, and an upper exhaust water jacket 80. Further, the lower exhaust water jacket 90 is formed by the second water jacket core 120, and the exhaust collecting portion 24 is formed by the exhaust core 130. Further, a single air vent passage R is formed by the connecting baseboard portions 140b and 150b. As shown in FIG. 15, the opening on the front surface 2 c side of the cylinder head 2 in the air vent passage R is closed with a cap C attached later.

  According to the present modification, the air exhaust passage R is provided by connecting the protrusion 81 of the upper exhaust water jacket 80 and the protrusion 91 of the lower exhaust water jacket 90, so the lower exhaust water jacket is provided. When the air in 90 flows through the protrusion 91, the air is discharged to the protrusion 81 of the upper exhaust water jacket 80 through the air vent passage R. As a result, it is possible to reduce the air remaining in the lower exhaust water jacket 90 and to improve the cooling efficiency of the exhaust collecting portion 24.

  The air vent passage R is integrally formed with the first water jacket core 110 for forming the upper exhaust water jacket 80 when the cylinder head 2 is cast, and the first water jacket core 110 is made of gold. Since it is formed by the connecting baseboard part 140b of the first baseboard 140 held at a predetermined position of the mold and the connecting baseboard part 150b of the second baseboard 150 superimposed on the first baseboard 140, the cylinder The air vent passage R can be formed by using the first baseboard 140 and the second baseboard 150 necessary for casting the head 2. Accordingly, it is not necessary to form the air vent passage R by machining or the like, so that the work of forming the air vent passage R is facilitated.

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 24d Downstream side part 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 Protrusion 90 Lower exhaust water jacket 91 Protrusion R Air vent passage (air vent means)
E Internal combustion engine Lc Cylinder axis 110 Core for first water jacket (upper core)
120 Core for the second water jacket (lower core)
140 First skirting board (upper core holding means)
140a Baseboard part for holding 140b Baseboard part for connection 150 Second baseboard (lower core holding means)
150a Holding skirting part 150b Connecting skirting part 200 Casting die apparatus 210 Upper mold 220 Lower mold 230 Side mold

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 portion for collecting the plurality of exhaust ports inside 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 lower exhaust water jacket has a protruding portion that is arranged to protrude toward the upper exhaust water jacket and to face the downstream side portion of the exhaust collecting portion,
A water jacket structure for a cylinder head, characterized in that an air bleeding means for discharging air to the outside of the lower exhaust water jacket is provided at an upper portion of the protrusion in the cylinder axial direction.   The air venting means is integrally formed with a lower core for forming the lower exhaust water jacket during casting of the cylinder head, and holds the lower core in a predetermined position of a mold. 2. The water jacket structure for a cylinder head according to claim 1, wherein the water jacket structure is formed by side core holding means.   3. The cylinder head according to claim 1, wherein the upper exhaust water jacket and the lower exhaust water jacket form mutually independent flow paths inside the cylinder head. 4. Water jacket structure.   The air venting means is integrally formed with an upper core for forming the upper exhaust water jacket during casting of the cylinder head, and holds the upper core at a predetermined position of the mold. The water jacket structure for a cylinder head according to claim 2, wherein the water jacket structure is formed by holding means and the lower core holding means superimposed on the upper core holding means.

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