JP2014084738A - Cooling liquid passage structure of cylinder head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling liquid passage structure of a cylinder head with improved cooling efficiency by making a flow of cooling liquid of a water jacket of a cylinder head sufficient.SOLUTION: An exhausting water jacket 70 has: an upper exhausting water jacket 80 that is arranged on an upper side in a cylinder axial line Lc direction to an exhaust collection part 24, and in which cooling liquid flows in an aligning direction Lb of a cylinder 1a; and a lower exhausting water jacket 90 that is arranged on a lower side in the cylinder axial line Lc direction to the exhaust collection part 24 and in which the cooling liquid flows in the aligning direction Lb of the cylinder 1a. A cooling liquid outlet 83 of the upper exhausting water jacket 80, and a cooling liquid outlet 93 of the lower exhausting water jacket 90 are separately provided on a cylinder head 2, respectively. The upper exhausting water jacket 80 and the lower exhausting water jacket 90 are formed by cooling liquid passages independent from each other inside the cylinder head 2.

Description

  The present invention relates to a coolant passage structure of a cylinder head provided in an engine mounted on a vehicle.

Conventionally, downsizing of an internal combustion engine such as an engine has been desired due to demands for improving fuel consumption and reducing CO _2. However, such an internal combustion engine is provided with a supercharger in order to eliminate torque shortage due to downsizing. There are many. On the other hand, in order to reduce the size and weight of an internal combustion engine, an internal combustion engine has been developed in which an exhaust collecting portion for collecting a plurality of exhaust ports extending from a plurality of combustion chambers is integrally formed in a cylinder head. The exhaust collecting part tends to be hot, and it is important to cool the exhaust collecting part sufficiently to prevent thermal damage to the turbocharger, especially when a turbocharger is arranged immediately downstream of the exhaust collecting part. become. Therefore, in such a cylinder head, in addition to the combustion chamber water jacket for cooling the combustion chamber, an exhaust water jacket for cooling the exhaust port and the exhaust collecting portion is provided.

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

  In addition, as a water jacket that improves the cooling efficiency of the cylinder head without increasing the flow rate of the coolant, it is possible to cool the exhaust manifold side surface in the cylinder head in which the exhaust manifold is integrally formed. In addition, an improved installation method of a water jacket core and an exhaust port core during casting of a cylinder head is known (for example, see Patent Document 2).

JP 2010-209749 A German Patent Application No. 102008059832

  However, in the cooling passage structure of the cylinder head described in Patent Document 1, since there is a communication portion that communicates the upper and lower exhaust water jackets of the exhaust collecting portion, the flow of the coolant in the exhaust water jacket Becomes complicated. For this reason, the flow velocity inside the exhaust water jacket may decrease or a portion (stagnation portion) where the coolant may stay may be generated, and the cooling efficiency of the exhaust water jacket may decrease. On the other hand, if the capacity of the water jacket is increased and the flow rate of the coolant is increased in order to solve this problem, downsizing of the cylinder head and the water pump is hindered.

  Further, in the cylinder head in which the exhaust manifold described in Patent Document 2 is integrated, the cooling between the exhaust ports and the like is performed by connecting the upper exhaust water jacket and the lower exhaust water jacket through the communication path and circulating the coolant. It improves efficiency and prevents the generation of air pockets. However, the provision of the communication path is likely to cause a stagnation of the cooling liquid inside the water jacket. Therefore, in order to improve the cooling efficiency or eliminate the lack of cooling, the cooling liquid There is a problem that measures must be taken, for example, by increasing the flow rate.

  The present invention has been made in view of these problems, and it is an object of the present invention to provide a cylinder head coolant passage structure that improves the cooling efficiency by improving the coolant flow in the water jacket of the cylinder head. And

  A coolant passage structure for a cylinder head according to the present invention includes a plurality of combustion chamber tops formed on a bottom surface of the cylinder head, a plurality of intake ports and a plurality of exhaust ports respectively communicating with the plurality of combustion chamber tops, A coolant passage structure for a cylinder head, comprising: an exhaust collecting portion formed inside the cylinder head and communicating with the plurality of exhaust ports; and an exhaust water jacket for cooling the exhaust collecting portion. The upper water jacket is disposed on the upper side in the cylinder axial direction with respect to the exhaust collecting portion, and the upper exhaust water jacket in which coolant flows in the arrangement direction of the cylinders, and the lower side in the cylinder axial direction with respect to the exhaust collecting portion A lower exhaust water jacket in which the coolant flows in the cylinder arrangement direction, and the upper side A coolant inlet for supplying a coolant to the water jacket for the exhaust and the water jacket for the lower exhaust, respectively, and a coolant outlet of the upper exhaust water jacket; and a coolant outlet of the lower exhaust water jacket; Are provided separately in the cylinder head, and the upper exhaust water jacket and the lower exhaust water jacket are formed by independent coolant passages inside the cylinder head, respectively. To do.

According to such a configuration, the coolant passage structure of the cylinder head is such that the coolant outlet of the upper exhaust water jacket and the coolant outlet of the lower exhaust water jacket are provided separately in the cylinder head, and the upper exhaust Since the water jacket for water and the water jacket for lower exhaust are formed by independent coolant passages, the flow rate of the coolant inside each water jacket can be easily adjusted, and the coolant can flow without stagnation. It becomes possible. For this reason, it is possible to improve the cooling efficiency by improving the flow of the coolant in the water jacket of the cylinder head. In addition, the coolant passage structure of the cylinder head has an optimum flow path setting for each water jacket without providing branching means such as ribs, compared to the coolant passage structure branched from the common coolant inlet. Can be easily performed. Furthermore, since the two water jackets are independent coolant passages, it is possible to minimize the occurrence of stagnation in each water jacket.
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.

  Further, the coolant passage structure of the cylinder head according to the present invention is such that the upper exhaust water jacket and the lower exhaust water jacket are such that the flow rate of the coolant flowing through the lower exhaust water jacket is the upper exhaust water jacket. It is preferably formed so as to be faster than the flow rate of the coolant flowing through the water jacket.

  According to such a configuration, the upper exhaust water jacket and the lower exhaust water jacket form mutually independent flow paths inside the cylinder head, so that the cooling water is forced to be deflected inside the cylinder head. There is no need for branching, and the flow of the cooling liquid can be separated from each other to suppress a decrease in the flow rate and the occurrence of a stay (stagnation part) of the cooling liquid. The exhaust water jacket is formed so that the flow rate of the coolant flowing through the lower exhaust water jacket is faster than the flow rate of the coolant flowing through the upper exhaust water jacket. Thus, by increasing the flow rate of the lower exhaust water jacket that flows under the exhaust manifold of the cylinder head that becomes higher in temperature, the cooling efficiency can be improved without increasing the overall flow rate of the coolant. In addition, by cooling the cylinder head with a coolant with a high flow rate, the cylinder head can be cooled to a lower temperature than the one with the same volume of coolant passage by the increase in flow rate. In addition, the cooling efficiency is improved, so that the cylinder head can be reduced in size and weight.

  The upper exhaust water jacket or the lower exhaust water jacket is connected to an intake water jacket that flows around the plurality of intake ports, and serves as a combustion chamber water jacket that cools the top of the combustion chamber. The cooling water flow rate of the combustion chamber water jacket is formed so as to occupy the maximum ratio of the flow rate of the cooling fluid flowing inside the cylinder head. Next, the lower exhaust water jacket is formed. It is preferable that the ratio of the flow rate of the coolant is increased.

  According to such a configuration, the coolant passage of the water jacket is formed such that the flow rate of the coolant in the water jacket for the combustion chamber occupies the maximum ratio of the flow rate of the coolant flowing through the inside of the cylinder head. By forming the lower exhaust water jacket so that the ratio of the coolant flow rate is higher, the mating surface of the cylinder head below the exhaust manifold, which becomes hot near the top of the combustion chamber, is cooled more efficiently. can do.

  The combustion chamber water jacket is connected to the upper exhaust water jacket or the lower exhaust water jacket, and the combustion chamber water jacket is formed so that the coolant flows in the arrangement direction of the cylinders. It is preferable that

  According to such a configuration, the combustion chamber water jacket is formed so that the coolant flows in the arrangement direction of the cylinders, so that the shape of the water jacket is complicated, and the flow of the coolant in the upper portion of the combustion chamber that becomes a high temperature Therefore, the flow rate and cooling efficiency of the cooling liquid can be maintained well. Furthermore, the upper exhaust water jacket or the lower exhaust water jacket can reduce the flow rate of the coolant that is about to flow out to the exhaust assembly portion by using an independent coolant passage. The surroundings of the spark plug can be cooled effectively.

  Further, the upper exhaust water jacket or the lower exhaust water jacket has a coolant inlet on one side in the arrangement direction of the cylinders, and the upper exhaust water jacket or the lower exhaust water jacket is It is preferable that a plurality of coolant inlets are provided below the plurality of exhaust ports.

According to such a configuration, for example, the combustion chamber water jacket that covers the upper part of the combustion chamber that is at a high temperature has a relatively complicated structure when the coolant inlet is provided on one side of the cylinder arrangement direction. However, since the cooling liquid can be flowed without dropping the flow rate by the longitudinal flow in the cylinder row direction, the cooling efficiency can be improved. The upper exhaust water jacket formed in the independent coolant passage or the lower exhaust water jacket includes a plurality of coolant inlets disposed below the plurality of exhaust ports. Since the combustion chamber side portion can be reliably cooled, the cooling efficiency of the exhaust manifold can be improved while reliably cooling the high temperature combustion chamber side.
In addition, since the water jacket guides the coolant from the cylinder block directly to the upper exhaust water jacket on the split side or the lower exhaust water jacket, the coolant can also flow between the exhaust ports. The cylinder head can be efficiently cooled.

  Further, the upper exhaust water jacket or the lower exhaust water jacket has a coolant inlet on one side in the arrangement direction of the cylinders, and the upper exhaust water jacket or the lower exhaust water jacket is Preferably, a plurality of coolant inlets disposed between the cylinders are provided.

  According to such a configuration, the upper exhaust water jacket or the lower exhaust water jacket formed in the independent coolant passage has the coolant inlet communicating with the coolant passage of the cylinder block between the cylinders. Therefore, the combustion chamber side portion, which is the dividing surface, can be reliably cooled, so that the cooling efficiency of the aggregate portion of the exhaust manifold can be improved while reliably cooling the high temperature combustion chamber side.

  Of the upper exhaust water jacket or the lower exhaust water jacket, the exhaust water jacket not connected to the combustion chamber water jacket has a plurality of coolant inlets formed on the top side of the combustion chamber. Preferably, the coolant is formed so as to flow along the exhaust side surface of the cylinder head and then flow in the cylinder arrangement direction.

  According to such a configuration, the upper exhaust water jacket or the lower exhaust water jacket has a plurality of coolant inlets formed not on the end of the cylinder in the arrangement direction but on the side of the combustion chamber, so that the cylinder block Can improve the cooling efficiency on the top side of the combustion chamber where the coolant introduced from the coolant passage on the side reaches a high temperature, and reduce the cooling unevenness in the cylinder arrangement direction to achieve uniform cooling it can. Further, since the water jacket is provided with a dedicated coolant inlet, the flow rate of the coolant can be set easily and accurately.

  Further, the coolant inlet of the upper exhaust water jacket, the coolant inlet of the lower exhaust water jacket, and the coolant inlet of the combustion chamber water jacket are separately formed in the head gasket. It is preferable to communicate with the gasket coolant inflow hole.

  According to such a configuration, the coolant inlet of each water jacket can easily set the flow path only by adjusting the diameter of the head gasket, and the upper exhaust water jacket and the lower exhaust water jacket By making one of the channels independent of each other, branching at the coolant inlet can be made unnecessary, so that the coolant can be prevented from stagnating.

  Of the upper exhaust water jacket and the lower exhaust water jacket, the exhaust water jacket to which the combustion chamber water jacket is not connected is farthest from the coolant outlet of the exhaust water jacket. Preferably, an additional coolant inlet is formed between the exhaust ports of the cylinders.

  According to such a configuration, in the exhaust water jacket to which the combustion chamber water jacket is not connected, the additional coolant inlet is formed between the exhaust ports of the cylinders farthest from the coolant outlet of the exhaust water jacket. Can increase the flow rate and flow rate of the coolant. For this reason, it is possible to effectively prevent the stagnation of the coolant at the junction with the coolant of the other cylinders.

  ADVANTAGE OF THE INVENTION According to this invention, the coolant flow structure of the cylinder head which improved the cooling efficiency by making the flow of the coolant of the water jacket of a cylinder head favorable can be provided.

It is sectional drawing of the internal combustion engine which has the coolant passage 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 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 disassembled perspective view which shows the 1st modification of the coolant passage structure of the cylinder head which concerns on this embodiment. It is a top view which shows the 1st modification of the water jacket for intake, the water jacket for combustion chambers, and the water jacket for upper side exhaust. FIG. 6 is a bottom view showing a first modification of a lower exhaust water jacket, an intake water jacket, and a combustion chamber water jacket. It is a disassembled perspective view which shows the 2nd modification of the coolant passage structure of the cylinder head which concerns on this embodiment. FIG. 10 is a bottom view showing a second modification of the lower exhaust water jacket, the intake water jacket, and the combustion chamber water jacket.

  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 coolant passage structure of 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, for example, 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. A cylinder head 2 coupled to the upper end of the block 1, a gasket 3 installed between the cylinder block 1 and the cylinder head 2, and a head cover (not shown) coupled to the upper end of the cylinder head 2. An engine body is provided.

The internal combustion engine E is a multi-cylinder internal combustion engine that includes four cylinders 1a, pistons 4 that are reciprocally fitted in the cylinders 1a, and crankshafts 6 that are connected to the pistons 4 via connecting rods 5. Yes, it is mounted on the vehicle to be mounted in a horizontally placed 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, which is a direction 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. 8 and 9). A coolant cooled by a radiator (not shown) is supplied to one end side of the block-side water jacket 10. Further, the block-side water jacket 10 communicates with an intake water jacket 50 and a lower exhaust water jacket 90 of the cylinder head 2 which will be described later via the through holes 32, 35 and the like of the gasket 3, and both are cooled. Supplying liquid. 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 portion 21 is a plurality of substantially conical recesses formed 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, and communicate with each other in the 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 formed inside the cylinder head 2, provided at a portion projecting forward from the cylinder block 1, and communicated with the exhaust port 23 (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). In addition, outlet openings 63, 83, and 93 (exhaust side outlet portion 2g) serving as outlets for cooling liquid in the head side water jacket 40 described later are formed on the left side surface 2e (exhaust side surface) of the cylinder head 2. Yes. 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 in the cylinder head 2, and includes an intake water jacket 50 for cooling the intake port 22, and a combustion chamber. A combustion chamber water jacket 60 for cooling the top portion 21 and an exhaust water jacket 70 for cooling the exhaust port 23 and the exhaust collecting portion 24 are provided.

  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 is disposed on the upper side in the cylinder axis Lc direction with respect to the exhaust port 23 and the exhaust collecting portion 24, and the upper exhaust water jacket 80 in which the coolant flows in the arrangement direction Lb of the cylinders 1 a and the exhaust port 23. And a lower exhaust water jacket 90 that is disposed on the lower side in the cylinder axis Lc direction with respect to the exhaust collecting portion 24 and in which the coolant flows in the arrangement direction Lb of the cylinders 1a.

  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 lower exhaust water jacket 90. That is, in the exhaust water jacket 70, the upper exhaust water jacket 80 and the lower exhaust water jacket 90 form independent coolant passages inside the cylinder head 2. The exhaust water jacket 70 is formed such that the flow rate of the coolant flowing through the lower exhaust water jacket 90 is faster than the flow rate of the coolant flowing through the upper exhaust water jacket 80.

  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 flow path portion through which a cooling liquid for cooling the intake port 22 (see FIG. 1) flows. It extends while meandering so as to cross the side in the left-right direction. 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 flow path portion through which a coolant for cooling the combustion chamber top portion 21 (see FIG. 1) flows, and extends above each combustion chamber top portion 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 a combustion chamber side inflow portion 61 (coolant inlet) serving as an inlet for two coolants that open to the bottom surface 2a of the cylinder head 2 at the right end (see FIG. 5). 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. Of the front end portion of the upper exhaust water jacket 80, the protruding portion 81 is not provided in the portion 82 corresponding to the opening 24 a of the exhaust collecting portion 24. The upper exhaust water jacket 80 has an outlet opening 83 (cooling liquid outlet) that opens to the left side surface 2e of the cylinder head 2 and serves as a cooling liquid outlet at the left end (see FIG. 2). .

  Incidentally, with reference to FIG. 5, an intake port 22 (not shown) 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 side of each exhaust port 23 and the exhaust collecting portion 24 (see FIG. 6). (See FIG. 1). 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. Of the front end portion of the lower exhaust water jacket 90, the projecting portion 91 is not provided in the portion 92 corresponding to the opening 24 a of the exhaust collecting portion 24. The lower exhaust water jacket 90 has an outlet opening 93 (coolant outlet) 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 lower exhaust water jacket 90 has eight exhaust-side inflow portions 94 (coolant inlets) 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. have. Thus, since the exhaust-side inflow portion 94 is provided immediately below the exhaust port 23, the exhaust port 23 can be efficiently cooled (see FIG. 4).

  An additional inflow portion 95 (additional coolant inlet) is provided between the two exhaust side inflow portions 94 on the farthest side from the outlet opening 93 (that is, the upstream side). In other words, of the upper exhaust water jacket 80 and the lower exhaust water jacket 90, the lower exhaust water jacket 90 (exhaust water jacket 70) on the side where the combustion chamber water jacket 60 is not connected is An additional inflow portion 95 (additional coolant inlet) is formed between the exhaust port 23 of the cylinder farthest from the outlet opening 93 (coolant outlet) of the exhaust water jacket 70.

  The combustion chamber water jacket 60 has a combustion chamber side inflow portion 61 (coolant inlet) on the right side in the arrangement direction Lb of the cylinders 1a, and is formed so that the coolant flows in the arrangement direction Lb. Of the upper exhaust water jacket 80 and the lower exhaust water jacket 90 other than the combustion chamber water jacket 60, the lower exhaust water jacket 90 includes a plurality of exhaust side inflow portions 94 (cooling) directly below the exhaust port 23. A liquid inlet) is formed.

  As shown in FIG. 3, the exhaust collecting portion 24 and the head-side water jacket 40 are composed of a second water jacket core 200, an exhaust core 300, and a first water which are sand molds as shown in FIG. The jacket core 100 is formed in this order from below in a cavity of a casting mold (not shown) of the cylinder head 2. 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 imaginary 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 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. 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 (32a to 32h) and the exhaust-side through-hole 35 (35a to 35h) are some of the holes located on the right side (holes far from the outlet openings 63, 83, and 93), with some exceptions. Is formed with a large diameter, and the hole located on the left side (the hole closer to the outlet openings 63, 83, 93) is formed with a small diameter, so that the outlet openings 63, 83, It is formed so that the flow rate of the coolant flowing in the vicinity of 93 is increased.

  The exhaust side inflow portion 94 (coolant inlet) of the lower exhaust water jacket 90 and the combustion chamber side inflow portion 61 (coolant inlet) of the combustion chamber water jacket 60 are connected to the gasket 3 (head gasket). The gasket coolant inflow holes (32 to 36) and the water jacket 10 on the block side of the cylinder block 1 communicate with each other. The upper exhaust water jacket 80 is formed so that the coolant flows into the upper exhaust water jacket 80 through the communication portion 62 (coolant inlet) of the combustion chamber water jacket 60.

  In the intake side through hole 32, for example, the intake side through hole 32a disposed at a position farthest from the outlet opening 63 (exhaust side outlet 2g) is formed in a hole having a diameter larger than 3 mm. The intake side through hole 32b adjacent to the outlet opening 63 side of the intake side through hole 32a is formed as a long hole having a diameter larger than 3 mm. Among the intake side through holes 32, the intake side through holes 32 (32c to 32h) arranged closest to the outlet opening (exhaust side outlet 2g) side are small holes with a diameter of 3 mm.

In the exhaust side through hole 35, for example, the exhaust side through holes 35a to 35d arranged on the position farthest from the outlet opening 93 (exhaust side outlet part 2g) have a diameter of 6 mm. Exhaust side through holes 35e and 35f adjacent to the outlet opening 93 (coolant outlet) side of the exhaust side through hole 35d are formed as holes having a diameter of 5 mm. The exhaust side through holes 35g and 35h arranged at the position closest to the outlet opening 93 (exhaust side outlet part 2g) of the exhaust side through hole 35f are small holes having a diameter of 4 mm.
As described above, the intake side through hole 32 and the exhaust side through hole 35 have a small diameter of the gasket coolant inflow hole disposed closer to the outlet openings 63 and 93, and the gasket coolant inflow hole serves as the outlet openings 63 and 93. The aperture is appropriately large depending on the position far from the center.
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.

  As described above, the upper exhaust water jacket 80 communicates with the intake water jacket 50 in which the coolant flows around the intake port 22 and is connected to the combustion chamber water jacket 60 that cools the combustion chamber top 21. ing. The flow passage cross-sectional area of the combustion chamber water jacket 60 is wide so that the flow rate of the coolant in the combustion chamber water jacket 60 occupies the maximum ratio of the flow rate of the coolant flowing in the cylinder head 2. Next, the flow passage cross-sectional area of the lower exhaust water jacket 90 is formed so that the ratio of the flow rate of the coolant in the lower exhaust water jacket 90 is increased.

≪Action≫
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. 11 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. 12 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). 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. 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 Y4) flowing in the right direction on the rear side of the cylinder 1a along the block-side water jacket 10 is partially taken into the intake-side through-hole 32 ( 32a to 32h) and flows into the intake water jacket 50 from the intake-side inflow portion 51 (arrow Y8a). At this time, the intake-side through holes 32c to 32h arranged closer to the outlet opening 63 (exhaust-side outlet 2g) are arranged at positions far from the outlet opening 63 (exhaust-side outlet 2g). Therefore, the flow velocity of the coolant (arrow Y8a) flowing into the intake-side inflow portion 51 disposed near the outlet opening 63 (exhaust-side outlet portion 2g) is smaller than the intake-side through holes 32a and 32b. Get faster. If the flow rate of the coolant (arrow Y8a) increases, the flow rate of the coolant flowing to the intake-side inflow portion 51 increases within a predetermined time according to the flow rate, and the cross-sectional area of the coolant passage can be reduced. At the same time, the cooling capacity and cooling efficiency of the water jacket can be improved.

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). The coolant (arrow Y 6) flowing from the inter-axis slit 13 to the inter-axis inflow portion 53 has a flow resistance reduced by forming the inter-axis through hole 33 in the gasket 3 in accordance with the position of each constricted portion 12. And flows smoothly.
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). The combustion chamber side through-hole 34 disposed at a position far from the outlet opening 63 (exhaust side outlet 2g) is closer to the inlet side than the outlet opening 63 (exhaust side outlet 2g). It is formed larger than the diameters of the through hole 32 and the inter-axis through hole 33 so that the coolant (Y9) flows slowly.

As shown in FIG. 11, the coolant flowing into the right end portion of the combustion chamber water jacket 60 from the combustion chamber side inflow portion 61 flows substantially straight from right to left toward the outlet opening 63 at the left end portion (arrow). Y10), the flow of the coolant is smooth because the flow resistance is small. 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. For this reason, the coolant flows smoothly without stagnating and there is little pressure loss. 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. 12, the coolant (arrow Y14) that has flowed into the lower exhaust water jacket 90 from the exhaust side inflow portion 94 flows toward the front 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 flowing in is guided to the right front portion 90a of the lower exhaust water jacket 90 and is easy to flow toward the outlet opening 93 at a higher flow velocity than other portions. 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.
When comparing the lower exhaust water jacket 90 and the upper exhaust water jacket 80, the independent independent lower exhaust water jacket 90 has a larger number of exhaust inflow portions 94 and additional inflow portions 95. Since the flow path is formed so that the coolant flowing in from the outlet smoothly flows toward the outlet opening 93 without resistance, the flow rate of the coolant flowing in the lower exhaust water jacket 90 is set to It is formed so as to be faster than the flow rate of the jacket 80.

  As described above, according to the coolant passage structure of the cylinder head according to the present embodiment, the upper exhaust water jacket 80 and the lower exhaust water jacket 90 have independent flow paths inside the cylinder head 2. Since it forms, it can isolate | separate the flow of a cooling fluid mutually and can suppress generation | occurrence | production of the fall of a flow rate, and the stay location (stagnation part) of a cooling fluid. And since the fall of the flow rate and generation | occurrence | production of the stay location (stagnation part) of a coolant can be minimized, since the flow rate of the coolant which flows through the inside of the water jacket 70 for exhaust can be raised, a small flow path Even in a cooling passage having a cross-sectional area, it is possible to efficiently cool the exhaust collecting portion 24 and the like by increasing the supply flow rate of the cooling liquid per unit of time. Thereby, the capacity | capacitance of the water jacket 70 for exhaust_gas | exhaustion can be made small, and by extension, size reduction of the cylinder head 2 and size reduction of a water pump can be achieved.

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

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 the core is suppressed, and the alignment of the cores is not required, so that the manufacturing process (core installation work, positioning of the cores, etc.) 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.
In addition, the combustion chamber water jacket 60, the upper exhaust water jacket 80, and the lower exhaust water jacket 90 have outlet openings 63, 83, and 93 (coolant outlets) formed separately from each other. When designing a coolant passage having a good cooling performance by increasing the coolant flow rate, the combustion chamber side inflow portion 61 (coolant inlet), the exhaust side inflow portion 94 (coolant inlet), and the additional inflow portion 95 (additional cooling) Since the flow rate can be adjusted based on the relationship between the diameter of the outlet openings 63, 83, and 93 with respect to the diameter of the liquid inlet), it is easy to set the flow rate of the coolant in the coolant passage as desired, and the flow rate of the coolant Easy to manage.

≪First modification≫
As mentioned above, although the coolant passage structure of the cylinder head according to the present embodiment has been described in detail with reference to the drawings, 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. Hereinafter, modifications of the embodiment will be described. In addition, the already demonstrated structure attaches | subjects the same code | symbol and abbreviate | omits the description. FIG. 13 is an exploded perspective view showing a first modification of the coolant passage structure of the cylinder head according to the present embodiment. FIG. 14 is a plan view showing a first modification of the intake water jacket, the combustion chamber water jacket, and the upper exhaust water jacket. FIG. 15 is a bottom view showing a first modification of the lower exhaust water jacket, the intake water jacket, and the combustion chamber water jacket.

  In the above embodiment, as shown in FIGS. 3 and 4, the upper exhaust water jacket 80 and the combustion chamber water jacket 60 are integrally formed on the upper exhaust water jacket 80, so that the upper exhaust water jacket 90 is disposed on the upper side. Although the provided head side water jacket 40 was demonstrated, it is not limited to this. For example, as shown in FIGS. 13 to 15, the coolant passage structure of the cylinder head according to the present invention is provided with an upper exhaust water jacket 80 </ b> A on the upper side, and a lower exhaust water jacket 90 </ b> A and an intake side on the lower side. It may be the head side water jacket 40A in which the water jacket formed integrally with the water jacket 50A and the combustion chamber water jacket 60A is separated.

In this case, as shown in FIG. 14, the upper exhaust water jacket 80A includes a plurality of coolant inlets 84A disposed between the cylinders, so that the coolant (arrow Y20) is supplied to each coolant inlet 84A. Through the periphery of the cylinder toward the front side surface portion 80Ab of the upper exhaust water jacket 80A, the coolant (arrow Y21) and the coolant flowing out from each coolant inlet 84A (arrow Y20) and the front side It is formed so as to flow straightly toward the outlet opening 83A (coolant outlet) while increasing the flow velocity while merging in the side surface 80Ab.
In other words, the exhaust water jacket 70A (upper exhaust water jacket 80A) on the side of the upper exhaust water jacket 80A or the lower exhaust water jacket 90A to which the combustion chamber water jacket 60A is not connected is the coolant inlet. 84A is formed between the cylinders, and after the coolant flowing out from each coolant inlet 84A flows along the left side surface 2e (exhaust side surface) of the cylinder head 2, the outlet opening in the arrangement direction Lb of the cylinders 1a It is formed to flow while merging toward 83A.

  The upper exhaust water jacket 80A is formed in this manner, so that the peripheral portion of the cylinder and the front side surface portion 80Ab (exhaust side) of the upper exhaust water jacket 80A can be efficiently cooled. Therefore, it is possible to cool the front side surface portion 80Ab, which is impossible with the conventional integrated water jacket.

Therefore, on the back side (inside) of the mating surface of the first water jacket core 100A and the second water jacket core 200A around the opening 24a of the exhaust collecting portion 24, there is an upper exhaust water jacket 80A. A lower exhaust water jacket 90A (see arrow Y22 in FIG. 15) is provided. For this reason, it becomes possible to reduce the temperature of the installation site | part of the internal thread part N and gasket bead part (illustration omitted) for joining the mating surface.
In order to prevent the melt from flowing around the mating surface of the first water jacket core 100A and the second water jacket core 200A during casting, the upper and lower water jackets are formed. It is preferable to form a gap between the jackets.

  Further, since the coolant inlet 84A forms a longitudinal flow that flows from the cylinder axis portion toward the outlet opening 83A (coolant outlet), the upper surface of the exhaust port 23 can be cooled over a wide range. . Since the coolant inlet 84A is disposed between the cylinders, the coolant can be supplied from the portion between the cylinder shafts. Therefore, another circuit or bypass circuit for supplying the coolant to the upper exhaust water jacket 80A. Is unnecessary. Further, since the coolant inlet 84A serves as a leg portion that plays a role of positioning when the upper first water jacket core 100A is set, the core can be accurately assembled at a predetermined position. The assembly work of the child can be simplified.

  The upper exhaust water jacket 80A and the lower exhaust water jacket 90A are provided with a coolant inlet 84A for supplying the upper exhaust water jacket 80A with the coolant on the cylinder block 1 side, and the lower exhaust water jacket 90A. Are provided with a combustion chamber side inflow portion 61A (coolant inlet) for supplying coolant on the cylinder block 1 side, an outlet opening 83A (coolant outlet) of the upper exhaust water jacket 80A, and a lower exhaust water jacket. A 90A outlet opening 93A (coolant outlet) is separately provided in the cylinder head 2 and formed by independent coolant passages.

Further, as shown in FIG. 15, the lower exhaust water jacket 90A is connected to the intake water jacket 50A flowing around the plurality of intake ports 22 (see FIG. 1), and the combustion chamber top 21 (FIG. 1). And a combustion chamber water jacket 60 </ b> A covering the reference). For this reason, since the upper and lower water jackets are divided in the vicinity of the combustion chamber top 21, it is possible to efficiently and reliably cool the combustion chamber top 21 that is at a high temperature and the vicinity of the exhaust manifold assembly.
The lower exhaust water jacket 90A and the combustion chamber water jacket 60A that covers the combustion chamber top portion 21 and cools the periphery of the combustion chamber are connected by connecting portions 96A and 96A respectively disposed at two positions on the left and right ends. Connected and integrally formed. A portion 67A between the lower exhaust water jacket 90A and the combustion chamber water jacket 60A around the combustion chamber is spaced apart between the left and right connecting portions 96A, 96A.

  As shown in FIG. 15, the combustion chamber water jacket 60A and the lower exhaust water jacket 90A have a combustion chamber side inflow portion 61A (coolant inlet) on the right side in the arrangement direction Lb of the cylinders 1a. The combustion chamber side through hole 34A (gasket coolant inflow hole) is arranged, and the coolant (arrows Y22, Y23, Y24) flowing in from the combustion chamber side inflow portion 61A is the intake water jacket 50A, the combustion chamber water jacket. The coolant passage is formed to flow in the arrangement direction Lb of the cylinder 1a from the right end of 60A and the lower exhaust water jacket 90A toward the left end outlet opening 93A (coolant exit).

In addition, as shown in FIG. 14, in order to cool efficiently, the plug arrangement | positioning part periphery part 68A is formed so that it may cool without dividing | segmenting the perimeter by the combustion chamber water jacket 60A arrange | positioned below. Has been.
Further, since the exhaust shaft-to-shaft portion 69A is formed at a location deviating from the flow line (arrow Y20) of the coolant flowing through the upper exhaust water jacket 80A, it is difficult to efficiently cool the upper exhaust water jacket 80A. The lower combustion chamber water jacket 60A is formed.

As described above, even if the present invention is configured as in the first modification, the water jacket is divided into the upper exhaust water jacket 80A disposed on the upper side, the lower exhaust water jacket 90A disposed on the lower side, and the like. By separating, a plurality of independent coolant passages can be formed, so that it is easy to adjust the flow rate of the coolant inside each water jacket, and it is possible to flow the coolant without stagnation.
In particular, as shown in FIGS. 14 and 15, the upper exhaust water jacket 80A and the lower exhaust water jacket 90A allow the coolant (arrows Y21 and 20) to move from the right end to the front side surfaces 80Ab and 90Ab. Since the flow rate increases along the inner wall surface toward the outlet openings 83A and 93A (coolant outlets), the flow rate of the coolant flowing in proportion to the flow rate increases, so the cylinder head 2 (see FIG. 1). The exhaust port 23 and the exhaust collecting portion 24 can be efficiently cooled.

  As a result, it is possible to cool the front side surface portion 80Ab, which was impossible with the conventional integrated water jacket described in Patent Document 1, and the cooling capacity and the cooling efficiency are increased by the increase in the flow rate of the coolant. Since the cross-sectional area of the coolant passage can be reduced, the capacity of the exhaust water jacket 70A (the upper exhaust water jacket 80A and the lower exhaust water jacket 90A) can be reduced, thereby reducing the size of the cylinder head 2. It is possible to reduce the weight.

Further, the cylinder periphery is cooled with coolant (arrow Y20) by the upper exhaust water jacket 80A, and the outlet opening 93A (coolant) from the right end to the left end by the coolant (arrow Y23) of the combustion chamber water jacket 60A. It is possible to efficiently cool the combustion chamber top 21 by flowing toward the outlet. Further, the coolant (arrow Y24) flowing through the intake water jacket 50A smoothly flows in the rear side surface 90Ab along the inner surface toward the outlet opening 93A (coolant outlet), so that it is efficiently cooled. be able to.
In this way, the upper exhaust water jacket 80A and the lower exhaust water jacket 90A form independent flow paths and separate outlet openings 83A and 93A (coolant outlets). It is easy to design the coolant flow path for eliminating the flow rate of the liquid and the location (stagnation part) of the coolant.

≪Second modification≫
FIG. 16 is an exploded perspective view showing a second modification of the coolant passage structure of the cylinder head according to the present embodiment. FIG. 17 is a bottom view showing a second modification of the lower exhaust water jacket, the intake water jacket, and the combustion chamber water jacket.
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 as shown in FIGS. Alternatively, the opening 24a of the exhaust collecting portion 24 may be formed.
Also, as shown in FIGS. 16 and 17, in the inter-shaft portion between the left and right connecting portions 62B, 62B, there is a connecting portion between the upper exhaust water jacket 80B and the combustion chamber water jacket 60B around the combustion chamber. A connecting portion 67B having a width that is longer in the left-right direction than 62B and 62B may be provided for firm connection. In this way, the rigidity of the core for forming the upper exhaust water jacket 80B and the combustion chamber water jacket 60B can be improved, so that the connecting portion 67B is broken during the water jacket casting operation. Can be prevented.

  The flow of the coolant in each water jacket shown in FIGS. 16 and 17 is substantially the same as that in the above embodiment, but will be described briefly. In each water jacket (combustion chamber water jacket 60B, upper exhaust water jacket 80B, and lower exhaust water jacket 90B), the coolant is the gasket coolant inflow holes 33B and 34B of the gasket 3 which is the coolant inlet. , 35B flows smoothly without meandering in the direction of the outlet openings 63B, 83B, 93B at the left end (arrows Y30, Y31, Y32, Y33), and approaches the outlet openings 63B, 83B, 93B. The flow rate is going up. As long as the coolant passages of the respective water jackets are formed as such, the installation positions of the gasket coolant inlet holes 33B, 34B, and 35B may be appropriately changed. For this reason, the additional through-hole 36 and the additional inflow portion 95 illustrated in FIG. 12 described in the present embodiment may be omitted as illustrated in FIG.

Further, since the lower exhaust water jacket 90B has the exhaust side through holes 35B formed on the left and right sides of the periphery of each cylinder, the periphery of the cylinder can be efficiently cooled. The coolant (arrows Y30 and Y31) flowing out from each exhaust side through-hole 35B flows in the front side surface portion 90Bb along the inner wall surface to the front side surface portion 90Bb, and then merges to increase the flow velocity to increase the flow rate. It flows toward the outlet opening 93B while cooling 90Bb and the exhaust collecting portion 24. For this reason, the lower exhaust water jacket 90 </ b> B can effectively cool the front side surface and the periphery of the exhaust collecting portion 24.
Further, as shown in FIG. 16, a notch 93Ba is provided at a position near the outlet opening 93B of the lower exhaust water jacket 90B, and in addition to the outlet openings 63B, 83B, 93B, a separate outlet opening is provided. (Not shown) may be arranged.

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

DESCRIPTION OF SYMBOLS 1 Cylinder block 1a Cylinder 2 Cylinder head 2a Bottom face 2e Exhaust side side 2g Exhaust side outlet 3 Gasket (head gasket)
10 Block side water jacket 21 Combustion chamber top part 22 Intake port 23 Exhaust port 24 Exhaust collecting part 32 Intake side through hole (gasket coolant inflow hole)
33 Inter-shaft through hole (gasket coolant inflow hole)
34, 34A Combustion chamber side through hole (gasket coolant inflow hole)
35, 35B Exhaust side through hole (gasket coolant inflow hole)
36 Additional through hole (gasket coolant inflow hole)
40, 40A, 40B Head side water jacket 50, 50A, 50B Water jacket for intake air 60, 60A, 60B Water jacket for combustion chamber 61, 61A Cooling liquid inlet 62 Connecting portion (cooling liquid inlet)
63, 63B, 83, 83A, 83B, 93, 93A, 93B Outlet opening (cooling liquid outlet)
70, 70A, 70B Exhaust water jacket 80, 80A, 80B Upper exhaust water jacket 84, 94 Exhaust side inlet 94 (coolant inlet)
90, 90A, 90B Lower exhaust water jacket 95 Additional inlet (additional coolant inlet)
E Internal combustion engine Lb Cylinder arrangement direction Lc Cylinder axis

Claims (9)

A plurality of combustion chamber tops formed on the bottom surface of the cylinder head;
A plurality of intake ports and a plurality of exhaust ports respectively communicating with the tops of the plurality of combustion chambers;
An exhaust assembly formed inside the cylinder head and communicated with the plurality of exhaust ports;
A coolant passage structure of a cylinder head having an exhaust water jacket for cooling the exhaust assembly part,
The exhaust water jacket is disposed on the upper side in the cylinder axial direction with respect to the exhaust collecting portion, and an upper exhaust water jacket in which the coolant flows in the arrangement direction of the cylinders;
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 in which the coolant flows in the arrangement direction of the cylinders,
A coolant inlet for supplying coolant to the upper exhaust water jacket and the lower exhaust water jacket is provided, respectively.
A coolant outlet of the upper exhaust water jacket and a coolant outlet of the lower exhaust water jacket are separately provided in the cylinder head, respectively.
The cylinder head coolant passage structure, wherein the upper exhaust water jacket and the lower exhaust water jacket are formed as independent coolant passages in the cylinder head.   The upper exhaust water jacket and the lower exhaust water jacket are configured such that the flow rate of the coolant flowing through the lower exhaust water jacket is faster than the flow rate of the coolant flowing through the upper exhaust water jacket. 2. A coolant passage structure for a cylinder head according to claim 1, wherein the coolant passage structure is formed. The upper exhaust water jacket or the lower exhaust water jacket is connected to an intake water jacket that flows around the plurality of intake ports, and is connected to a combustion chamber water jacket that cools the top of the combustion chamber. ,
The cooling water flow rate of the combustion chamber water jacket is formed so as to occupy the maximum ratio of the flow rate of the cooling liquid flowing inside the cylinder head. Next, the cooling liquid of the lower exhaust water jacket is formed. 3. The coolant passage structure for a cylinder head according to claim 1, wherein the ratio of the flow rate of the cylinder head is increased. The combustion chamber water jacket is connected to the upper exhaust water jacket or the lower exhaust water jacket,
4. The coolant passage structure of a cylinder head according to claim 3, wherein the combustion chamber water jacket is formed so that a coolant flows in an arrangement direction of the cylinders. The upper exhaust water jacket or the lower exhaust water jacket has a coolant inlet on one side in the arrangement direction of the cylinders,
5. The upper exhaust water jacket or the lower exhaust water jacket includes a plurality of coolant inlets disposed below the plurality of exhaust ports. A coolant passage structure for a cylinder head according to claim 1. The upper exhaust water jacket or the lower exhaust water jacket has a coolant inlet on one side in the arrangement direction of the cylinders,
5. The upper exhaust water jacket or the lower exhaust water jacket includes a plurality of coolant inlets disposed between the cylinders. The coolant passage structure of the cylinder head described.   Of the upper exhaust water jacket or the lower exhaust water jacket, the exhaust water jacket to which the combustion chamber water jacket is not connected has a plurality of coolant inlets formed on the top side of the combustion chamber, The coolant is formed so as to flow in the arrangement direction of the cylinders after flowing and gathering along the exhaust side surface of the cylinder head. Cylinder head coolant passage structure.   Gaskets formed separately in the head gasket, the coolant inlet of the upper exhaust water jacket, the coolant inlet of the lower exhaust water jacket, and the coolant inlet of the combustion chamber water jacket, respectively. The coolant passage structure for a cylinder head according to any one of claims 4 to 7, wherein the coolant passage structure communicates with a coolant inflow hole.   Of the upper exhaust water jacket or the lower exhaust water jacket, the exhaust water jacket to which the combustion chamber water jacket is not connected is the cylinder farthest from the coolant outlet of the exhaust water jacket. 9. The coolant passage structure for a cylinder head according to claim 8, wherein an additional coolant inlet is formed between the exhaust ports of the cylinder head.

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