JP5864401B2 - Water jacket structure of internal combustion engine - Google Patents

Description

  The present invention relates to a water jacket structure for an internal combustion engine.

  Conventionally, a coolant passage is formed on the upper surface of a partition wall that partitions between a plurality of cylinders provided in a cylinder block, and the partition wall that is at a high temperature is cooled.

  For example, in Patent Document 1, grooves (interaxial cooling grooves) are formed so as to face the cylinder block upper surface and the cylinder head lower surface between cylinder bores, and a cooling water passage is formed by these grooves, and one end of the passage is formed. And a cooling structure for an internal combustion engine in which the other end communicates with a water jacket of a cylinder head.

Japanese Utility Model Publication No. 63-138420

  However, since the conventional inter-axis cooling groove is formed in a narrow partition wall, the flow resistance is large, and it is difficult for the coolant to enter the groove. Therefore, there is a problem that a sufficient cooling effect is not obtained. On the other hand, if the groove width or depth is increased in order to increase the flow rate of the cooling liquid, there is a problem that the rigidity of the partition walls is lowered.

  The present invention has been made in view of these problems, and an object of the present invention is to increase the flow rate of the coolant flowing through the inter-axis cooling groove to increase the flow rate, thereby improving the cooling performance.

The present invention relates to a cylinder block having a plurality of cylinders and a block-side water jacket for cooling the plurality of cylinders, an intake / exhaust path communicating with the cylinder, and a head for cooling the intake / exhaust path A cylinder head having a side water jacket, and a gasket having a plurality of through-holes interposed between the cylinder block and the cylinder head for communicating the block side water jacket and the head side water jacket. A water jacket structure for an internal combustion engine, wherein the block-side water jacket opens to the upper surface of the cylinder block and is provided with a coolant introduction portion provided on one end side in the cylinder row direction, and the introduction One end side in the cylinder row direction A first flow path for flowing toward the other end side, a second flow path for flowing a coolant from the other end side in the cylinder row direction to the one end side on the opposite side of the first flow passage across the cylinder row, A third flow path for flowing a coolant from the first flow path to the second flow path on the other end side in the cylinder row direction, and the head-side water jacket is a bottom surface of the cylinder head and passes through the through-hole. The partition wall that separates the cylinders adjacent to each other in the cylinder block has an inflow portion that opens at a position corresponding to the hole, and is opened in a groove shape on the upper surface, and the first flow path and the first An inter-axis cooling groove that communicates with two flow paths is provided, and the gasket has the through hole at a position straddling the second flow path and the end of the inter-axis cooling groove on the second flow path side. and, the through-holes arranged in said straddling position, put the upper surface of the cylinder block And it is provided so as to overlap in both the opening of the opening and the inter-axial cooling channels of the second flow path.

  According to such a structure, it straddles the connection part of the 2nd flow path which is far from an introduction part among block side water jackets, and whose flow speed is comparatively slow, and the edge part by the side of the 2nd flow path of an inter-axis cooling groove. Since the through hole of the gasket is provided (so as to overlap), the coolant flows out from the end of the second flow path and the inter-axis cooling groove on the second flow path side through the through hole to the head side water jacket. Therefore, the resistance (pressure) of the cooling liquid on the second flow path side is lowered, and the cooling liquid easily flows from the first flow path side to the second flow path side in the inter-axis cooling groove. As a result, the stagnation of the cooling liquid in the inter-axis cooling groove is suppressed, the flow speed of the cooling liquid is increased, the flow rate is increased, and the cooling effect of the partition walls partitioning the cylinders is improved.

  The intake / exhaust path includes a plurality of combustion chamber tops provided corresponding to the cylinders, and a plurality of intake ports and a plurality of exhaust ports communicating with the combustion chamber tops. Comprises: an intake water jacket that cools the intake port; and a combustion chamber water jacket that communicates with the intake water jacket and cools the top of the combustion chamber. A through hole provided at a position corresponding to one end of the two flow paths in the cylinder row direction communicates with the water jacket for the combustion chamber, and is provided on the second flow path side of the second flow path and the inter-axis cooling groove. It is preferable that the through hole provided at a position straddling the end communicates with the intake water jacket.

  According to such a configuration, the through-hole leading to the water jacket for intake air is provided at the connection portion between the second flow path and the inter-axis cooling groove, and the coolant is supplied to the through-hole from the second flow path and the inter-axis cooling groove. Since it is supplied, the cooling efficiency of the partition wall by the inter-axis cooling groove is improved, and the cooling liquid can be sufficiently supplied to the intake water jacket. In addition, since the amount of the coolant reaching one end (downstream) of the second flow path increases, sufficient cooling from the through hole provided on the downstream side of the second flow path to the water jacket for the combustion chamber that has a relatively high cooling requirement. The amount of liquid can be supplied. Therefore, the cooling efficiency of the whole internal combustion engine can be increased.

  The first flow path is preferably provided on the exhaust side of the internal combustion engine.

  According to such a configuration, the cooling liquid is introduced from the exhaust side where the cooling requirement is relatively high, so that the flow rate is maintained and the cooling efficiency is increased. Further, of the both end portions of the inter-axis cooling groove, the end portion on the first flow path side, which has a smaller flow area and higher resistance than the end portion on the second flow path side, serves as an inlet for the coolant, and is formed by the through hole of the gasket. Since the end of the second flow path side, which has a lower flow path and has a lower resistance, becomes the outlet for the cooling liquid, the cooling liquid can be introduced from the first flow path side, which has a higher flow speed, and the flow speed in the inter-axis cooling groove can be secured. Therefore, effective cooling is possible with a small amount of coolant, and the water pump can be downsized.

  The cylinder head includes an exhaust collecting portion that collects the plurality of exhaust ports, and the head-side water jacket is a lower exhaust water provided on the lower side in the cylinder axial direction with respect to the exhaust collecting portion. It is preferable that a through-hole provided at a position corresponding to the first flow path among the plurality of through-holes communicates with the lower exhaust water jacket.

  According to such a configuration, a small amount of cooling can be achieved by supplying the coolant from the first flow path having a high flow rate and a low temperature to the lower exhaust water jacket disposed below the exhaust collecting portion having the highest temperature. Effective cooling is possible with the liquid, and the internal combustion engine can be downsized.

  According to the present invention, it is possible to improve the cooling performance by increasing the flow rate of the coolant flowing in the inter-axis cooling groove to increase the flow rate.

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 assembly 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 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. (A) is sectional drawing of the XI-XI arrow shown in FIG. 10, (b) is an enlarged view of the B section shown to (a). 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.

  An embodiment 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 flow path for a coolant that cools 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. 8 and 9). 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.

  The front surface 2c of the cylinder head 2 has two support holes 2f formed by connecting portions that connect the core installed in the cavity during casting and the baseboard supported by the mold. The support hole 2f is closed with a cap 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).

  The exhaust collecting portion 24 and the head-side water jacket 40 include the second water jacket core 200, the exhaust core 300, and the first water jacket core 100, which are sand molds as shown in FIG. The cylinder head 2 is formed by being installed in this order from below in a cavity of a casting mold (not shown). That is, since the installation of the core is completed simply by arranging the three cores so as to be stacked in order from the bottom, complication of the installation work of the core is suppressed.

FIG. 8 is an exploded perspective view for explaining the flow of the coolant from the block-side water jacket to the intake water jacket. FIG. 9 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. 10 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 FIG. 8 and FIG. 9, for convenience of explanation, portions of the head-side water jacket 40 other than the inflow portion are drawn with virtual lines (two-dot chain lines). In FIG. 10, 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. 8, 9, and 10, 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 part 11 and an upstream side for flowing the coolant flowing in from the introduction part 11 from one end side to the other end side in the cylinder row direction (right side to left side in the present embodiment). The second flow path downstream of the first flow path 15 and the flow path from the other end side in the cylinder line direction to the one end side (in this embodiment, from the left side to the right side) on the opposite side of the first flow path 15 across the cylinder line It has a flow path 16 and an intermediate third flow path 17 through which the coolant flows from the first flow path 15 to the second flow path 16 on the other end side (left side) in the cylinder row direction. The introduction part 11 is provided on the front side of the rightmost cylinder 1a and is formed wider than the other parts. 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 the space between the cylinders 1a (the partition wall 1b (see FIG. 11)). Further, on the upper surface of the partition wall 1b, a concave groove-shaped inter-axis cooling groove 13 that communicates the constricted portions 12 on the front side and the rear side is formed. Compared to the second flow path 16, the first flow path 15 is faster in the flow rate of the coolant by the amount closer to the introduction portion 11.

  Here, the inter-axis cooling groove 13 will be described in detail with reference to FIG. Fig.11 (a) is sectional drawing of the XI-XI arrow shown in FIG. 10, (b) is an enlarged view of the B section shown to (a).

  As shown in FIG. 11, the inter-axis cooling groove 13 is a groove recessed in the upper surface of the cylinder block 1, and is a coolant passage for cooling the partition wall 1b between the adjacent cylinders 1a. The inter-shaft cooling groove 13 is formed in the vicinity of the upper surface of the cylinder block 1 between the constricted portion 12 of the first flow path 15 disposed on the front side (exhaust side) and the second flow path 16 disposed on the rear side (intake side). The constriction 12 is communicated. The inter-axis cooling groove 13 is formed with a smaller width dimension than the length dimension. For this reason, the inter-axis cooling groove 13 has a large flow resistance of the coolant.

  As shown in FIGS. 8, 9, and 10 (mainly FIG. 10), 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.

Here, the inter-axis through hole 33 will be described in detail with reference to FIG.
As shown in FIG. 10, the inter-shaft through hole 33 flows through the coolant that has flowed through the inter-shaft cooling groove 13 and the block-side water jacket 10 (that is, the second flow path 16) on the rear side (intake side). And a through hole for guiding the coolant to the head-side water jacket 40 (more specifically, the inter-axis inflow portion 53 of the intake water jacket 50). The inter-axis through hole 33 is provided at a position straddling the rear (intake side) end 13 a of the inter-axis cooling groove 13 and the rear constricted portion 12. Thereby, the flow path resistance of the rear end portion 13a of the inter-axis cooling groove 13 is reduced. A through hole is not formed at a position corresponding to the front side (exhaust side) end portion 13 b of the inter-axis cooling groove 13.

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.
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. 8 and 9, the coolant (arrow Y1) that has flowed into the introduction portion 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). The coolant flows through the inter-axis cooling groove 13 from the front constricted portion 12 toward the rear constricted portion 12 (arrow Y6).

  As shown in FIG. 9, 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. 8, a part of the coolant (arrow Y 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). Further, the coolant (arrow Y6) passing through the inter-axis cooling groove 13 joins the constricted portion 12 on the rear side, passes through the inter-axis through hole 33 formed in the gasket 3, and sucks from the inter-axis inflow portion 53. Flows into 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).

  By the way, the inter-axis cooling groove 13 has a small width dimension as compared with the length dimension, so that the flow path resistance is large and the cooling liquid hardly flows. Therefore, in the present embodiment, as shown in FIG. 11B, the inter-shaft is located at a position straddling the rear side (intake side) end portion 13a of the inter-axis cooling groove 13 and the rear constricted portion 12. The through hole 33 is provided. According to such a configuration, the flow path resistance of the rear side (intake side) end portion 13a of the inter-shaft cooling groove 13 is reduced, so that the coolant easily flows out from the inter-shaft cooling groove 13, and the inter-shaft cooling is performed. The coolant in the groove 13 flows into the inter-axis inflow portion 53 of the intake water jacket 50 through the inter-axis through hole 33 together with the coolant flowing in the rear constricted portion 12 (arrows Y20 and Y21). Then, a negative pressure is generated in the vicinity of the rear end portion 13a of the inter-axis cooling groove 13 due to this flow, and the negative constriction causes the coolant in the front constricted portion 12 to flow from the front end portion 13b of the inter-axis cooling groove 13. It flows into the inter-axis cooling groove 13 (arrow Y22). Thereby, even if the flow path resistance (inflow resistance) on the upstream side of the inter-axis cooling groove 13 is relatively large, the cooling liquid can flow into the inter-axis cooling groove 13, so that it is sandwiched between the combustion chambers 7. The partition wall 1b of the cylinder block 1 that reaches a high temperature can be efficiently cooled. Note that the coolant flow indicated by the arrow Y20 and the arrow Y21 in FIG. 11B becomes the coolant flow indicated by the arrow Y8b in FIG. 8, and the coolant indicated by the arrow Y22 in FIG. 11B. Is the flow of the coolant indicated by the arrow Y6 in FIG.

  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. 8 and 9) 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. 8 and 9) 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. 8 and 9) of the cylinders 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.

  As described above, according to the water jacket structure of the cylinder head according to the present embodiment, the upper exhaust water jacket 80 and the lower exhaust water jacket 90 form mutually independent flow paths in 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 staying portion (stagnation portion) of the cooling liquid can be reduced as much as possible, the flow speed of the cooling liquid flowing through the inside of the exhaust water jacket 70 is increased and the cooling liquid amount is efficient. It becomes possible to cool the exhaust collecting part 24. Further, since the exhaust collecting portion 24 can be efficiently cooled with a small amount of coolant, the capacity of the exhaust water jacket 70 can be reduced, and the cylinder head 2 can be downsized.

  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 cooling efficiency of the exhaust collecting part 24 can be improved.

  Further, since the intake water jacket 50 communicates with the combustion chamber water jacket 60 and the combustion chamber water jacket 60 communicates with the upper exhaust water jacket 80, a plurality of cores used when casting the cylinder head 2 are used. Of these, the cores corresponding to the intake water jacket 50, the combustion chamber water jacket 60, and the upper exhaust water jacket 80 (that is, the first water jacket core 100 shown in FIG. 4) may be integrally formed. it can. Further, since the upper exhaust water jacket 80 and the lower exhaust water jacket 90 are separated from each other, it is not necessary to separately prepare a core for forming a communication path as in Patent Document 1. Thereby, the increase in a core is suppressed and the complication of a manufacturing process (core installation work) can be suppressed.

  Further, the upper exhaust water jacket 80 communicating with the combustion chamber water jacket 60 is formed so that the coolant flows in the arrangement direction Lb of the combustion chamber top portion 21, so that the flow velocity is large even if the flow channel area is large. Adjustment becomes easy. Therefore, it becomes easy to increase the flow rate and improve the cooling efficiency even with a small amount of coolant. Further, the lower exhaust water jacket 90 into which the coolant directly flows from the block-side water jacket 10 is also formed so that the coolant flows in the arrangement direction Lb of the combustion chamber top portion 21. Therefore, the same effect as described above can be obtained. Play.

  Further, according to such a configuration, the second flow path 16 that is far from the introduction portion 11 and has a relatively low flow rate in the block-side water jacket 10 and the end portion 13a of the inter-axis cooling groove 13 on the second flow path 16 side. Since the inter-axis through-hole 33 of the gasket is provided so as to straddle (overlap) the connection part of the second flow path 16 and the end 13a on the second flow path 16 side of the inter-axis cooling groove 13. The coolant flows out to the head side water jacket 40 through the inter-axis through hole 33. Therefore, the resistance (pressure) of the cooling liquid at the end 13a of the inter-axis cooling groove 13 on the second flow path 16 side is lowered, and the cooling liquid flows in the inter-axis cooling groove 13 from the first flow path 15 side to the second flow. It becomes easy to flow to the path 16 side. As a result, the retention of the coolant in the inter-axis cooling groove 13 is suppressed, the flow rate of the coolant is increased, and the cooling effect of the partition wall 1b that partitions the cylinders 1a is improved.

  Further, according to such a configuration, the inter-axis through hole 33 that communicates with the intake water jacket 50 is provided at the connection portion between the second flow path 16 and the inter-axis cooling groove 13, and the second through-axis 33 is provided in the second through-hole 33. Since the cooling liquid is supplied from the flow path 16 and the inter-axis cooling groove 13, the cooling efficiency of the partition wall 1 b by the inter-axis cooling groove 13 is improved, and the cooling liquid can be sufficiently supplied to the intake water jacket 50. Further, since the amount of the coolant reaching one end side (downstream side) of the second flow path 16 increases, the combustion chamber side through-hole 34 provided on the downstream side of the second flow path 16 has a relatively high cooling requirement. A sufficient amount of coolant can be supplied to the water jacket 60. Therefore, the cooling efficiency of the entire internal combustion engine E can be increased.

  Further, according to such a configuration, the cooling liquid is introduced from the introduction portion 11 provided on the exhaust side where the cooling demand is relatively high, so that the flow rate on the exhaust side is maintained and the cooling efficiency is increased. Further, of the both end portions 13a and 13b of the inter-axis cooling groove 13, the end portion 13b on the first flow path 15 side, which has a smaller flow area and higher resistance than the end section 13a on the second flow path 16 side, is cooled. Since the end portion 13a on the second flow path 16 side having a low resistance is expanded by the inter-axis through hole 33 of the gasket 3 and becomes the outlet of the cooling liquid, the liquid flow inlet is formed. The coolant can be introduced from the side of the first flow path 15 to ensure the flow velocity in the inter-axis cooling groove 13, and effective cooling can be performed with a small amount of coolant, and the water pump (not shown) can be downsized.

  In addition, according to such a configuration, the exhaust-side through-hole 35 extends from the first flow path 15 having a high flow velocity and a low temperature to the lower exhaust water jacket 90 disposed below the exhaust collecting portion 24 that has the highest temperature. By supplying the cooling liquid via, effective cooling can be performed with a small amount of cooling liquid, and the internal combustion engine E can be downsized.

  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 thickness dimension in the vertical direction of the communication portion 62 can be increased. The rigidity of the water jacket core 100 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.

DESCRIPTION OF SYMBOLS 1 Cylinder block 1a Cylinder 1b Partition 2 Cylinder head 21 Combustion chamber top part 22 Intake port 23 Exhaust port 24 Exhaust collecting part 24d Downstream side part 3 Gasket 33 Interaxial through-hole 10 Block side water jacket 11 Introducing part 13 Interaxial cooling groove 15 First flow path 16 Second flow path 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 E Internal combustion engine Lc Cylinder axis

Claims (4)

A cylinder block having a plurality of cylinders and a block-side water jacket for cooling the plurality of cylinders;
A cylinder head having an intake / exhaust path communicating with the cylinder, and a head-side water jacket for cooling the intake / exhaust path;
A water jacket structure for an internal combustion engine comprising: a gasket interposed between the cylinder block and the cylinder head and having a plurality of through holes for communicating the block-side water jacket and the head-side water jacket. There,
The block-side water jacket opens to the upper surface of the cylinder block, and introduces a coolant introduction portion provided on one end side in the cylinder row direction, and allows the coolant flowing in from the introduction portion to flow from one end side in the cylinder row direction. A first flow path for flowing toward the other end side, a second flow path for flowing a coolant from the other end side to the one end side in the cylinder row direction on the opposite side of the first flow passage across the cylinder row, and the cylinder A third flow path for flowing a coolant from the first flow path to the second flow path on the other end side in the column direction,
The head-side water jacket has a coolant inflow portion that opens at a position corresponding to the through hole on the bottom surface of the cylinder head,
The partition wall separating the cylinders adjacent to each other in the cylinder block is provided with an inter-axis cooling groove that opens in a concave groove shape on the upper surface and communicates the first flow path and the second flow path.
The gasket has the through hole at a position straddling the second channel and an end of the inter-axis cooling groove on the second channel side ,
The through-hole disposed in the straddling position is provided so as to overlap both the opening of the second flow path and the opening of the inter-shaft cooling groove on the upper surface of the cylinder block. Jacket structure. The intake / exhaust path includes a plurality of combustion chamber tops provided corresponding to the cylinders, a plurality of intake ports and a plurality of exhaust ports communicating with the combustion chamber tops,
The head-side water jacket includes an intake water jacket that cools the intake port, and a combustion chamber water jacket that communicates with the intake water jacket and cools the top of the combustion chamber.
Of the plurality of through holes, a through hole provided at a position corresponding to one end side of the second flow path in the cylinder row direction communicates with the combustion chamber water jacket,
The through hole provided at a position straddling the second flow path and the end of the inter-axis cooling groove on the second flow path side communicates with the intake water jacket. Water jacket structure of internal combustion engine.   The water jacket structure for an internal combustion engine according to claim 1 or 2, wherein the first flow path is provided on an exhaust side of the internal combustion engine. The cylinder head includes an exhaust collecting portion that collects the plurality of exhaust ports,
The head-side water jacket includes a lower exhaust water jacket provided on the lower side in the cylinder axial direction with respect to the exhaust collecting portion,
The through hole provided at a position corresponding to the first flow path among the plurality of through holes communicates with the lower exhaust water jacket. A water jacket structure for an internal combustion engine according to any one of the preceding claims.

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