JPH0635824B2 - Cylinder head cooling structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cooling structure for a cylinder head, and more specifically,
The present invention relates to a cylinder head cooling structure in which a first cooling water passage that passes directly above each cylinder and a second cooling water passage that surrounds the passage are formed inside the cylinder head. this is,
It is used in the field of cooling a cylinder head in a cross-flow type multi-cylinder engine.

(Prior Art) Generally, in a multi-cylinder engine, the portion directly above each cylinder between the intake port and the exhaust port is most strongly subjected to impact force and heat load due to explosion in each cylinder. For this reason, cracks and the like are likely to occur at that location, and the most effective cooling is required to reduce thermal stress and fatigue. In particular, as engine performance and output have been increasing in recent years and engine speed has been increasing, further improvement in cooling efficiency is required.

By the way, in cooling a multi-cylinder engine, cooling water from a radiator is first supplied to a water jacket of a cylinder block to cool the cylinder block, and then introduced into a water jacket of a cylinder head from the cylinder block side. Cooling the cylinder head and then returning it to the radiator (for example, in actual exploitation 5
6-171649 gazette). However, in such a cooling water path, since the temperature of the cooling water introduced into the cylinder head has already risen to some extent in the cylinder block, there is a difficulty in cooling the cylinder head.

As measures against this, there are cases where a method of directly supplying cooling water to the cylinder head and then leading it to the cylinder block, a method of independently cooling the cylinder head and the cylinder block, and the like are adopted. But in any case,
Since there is not enough space in the cylinder head as compared to the cylinder block, the water jacket formed in the cylinder head branches in the vicinity of the cylinder and merges again when passing through the cylinder. Therefore, even in the cylinder head, a portion having a high heat load (for example, a portion directly above each cylinder) that needs a strong cooling and a portion that does not have a high heat load are simultaneously cooled with the same cooling water, so that the heat load is high. It is not possible to sufficiently enhance the cooling efficiency at the location.

Further, it is also necessary to reinforce the above-mentioned portion having a high heat load as much as possible to improve the rigidity of the entire cylinder head. However, when a reinforcing means such as a rib is added, the flow of cooling water becomes a hindrance, resulting in a decrease in cooling efficiency.

(Object of the Invention) The present invention has been made in view of the above circumstances, and an object thereof is to improve the rigidity of the cylinder head itself while improving the cooling efficiency in a portion having a high heat load in the cylinder head. is there.

(Structure of the Invention) In order to achieve the above object, the invention described in the claims is premised on a cooling structure of a cylinder head of a cross-flow type multi-cylinder engine, and an internal space of a water jacket in the cylinder head is provided. A first cooling water passage extending from one end to the other end in the cylinder head in the cylinder arrangement direction by the partition wall, and the first cooling water communicating with the first cooling water passage at a position on the other end side of the cylinder head. It is divided into a second cooling water passage extending along the passage to one end in the cylinder head. While partitioning the first cooling water passage by the partition wall so as to pass through a portion sandwiched between the top surface of the top of each cylinder and the outer wall portions of the intake port and the exhaust port facing each other in each cylinder, The second cooling water passage is arranged so as to surround the first cooling water passage via the partition wall. The partition wall is integrally formed with each outer wall so as to connect the outer walls of the intake ports adjacent to each other in the cylinder arrangement direction and the outer walls of the exhaust ports adjacent to each other in the cylinder arrangement direction. The first cooling water passage is connected to the radiator so that cooling water from the radiator is introduced into the first cooling water passage from one end side position of the cylinder head, while the second cooling water passage is connected to the cylinder. The cooling water in the second cooling water passage is connected to the radiator so as to be returned to the radiator from a position on one end side of the head.

In the case of the above configuration, the cooling water from the radiator is introduced into the first cooling water passage. The first cooling water passage is partitioned by partition walls so as to pass through a portion sandwiched by the outer wall portions of the intake / exhaust ports facing each other directly above the cylinders and above the tops of the cylinders, and is formed in the cylinder arrangement direction. Therefore, the cooling water introduced above preferentially cools the upper part of each cylinder, which is a place with a particularly high heat load in the cylinder head. Then, the cooling water sent from one end of the cylinder head to the other end in the first cooling water passage is cooled to the second end at the other end.
After entering the cooling water passage, flowing through the second cooling water passage, returning to the one end side of the cylinder head again, it is recirculated to the radiator.

On the other hand, the partition walls for partitioning the first cooling water passages and the second cooling water passages integrally connect the outer walls of the intake / exhaust ports of each cylinder in the cylinder arrangement direction. As a result of the outer walls of the intake / exhaust ports arranged for each cylinder being firmly supported by each other, the rigidity of the entire cylinder head can be improved.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing.

FIG. 1 is an overall schematic view of an engine cooling system to which a cylinder head cooling structure of the present invention is applied. In the figure, 1 is a radiator, 2 is a water pump, 3 is an engine body, and the cooling water radiated by the radiator 1 is supplied to the engine body 3 via the water pump 2 and returned to the radiator 1 again. It has become so.

The engine body 3 includes four cylinders 4 arranged in a horizontal row.
4, and the intake port 5 and the exhaust port 6 are opposed to the top of each cylinder 4 from both sides in the direction orthogonal to the cylinder arrangement direction, as shown in detail in FIG. It is composed of a connected cross-flow type multi-cylinder engine.

The engine body 3 has a cylinder block 7 in which the bore of each cylinder 4 is formed, and a cylinder head 8 integrally fixed to the upper surface of the cylinder block 7. On top of each cylinder 4
A (see FIG. 4) and the outer walls 10 forming the intake / exhaust ports 5 and 6 are integrally formed.

A water jacket is provided around each cylinder 4 of the cylinder block 7. The respective water jackets are communicated between the adjacent cylinders 4 and 4, and the cooling water introduced from the second cooling water passage 9B, which will be described later, into the inside of the water jackets is roughly indicated by an arrow P. 1
It flows from the left end side in the drawing to the other end side (the right end side in the drawing) in the cylinder arrangement direction.

In addition, a water jacket 9 for passing cooling water is also provided in the space inside the cylinder head 8.
The inner space of the water jacket 9 is divided by the partition walls (side partition wall 11 and ceiling partition wall 14) from one end in the cylinder head 8 in the cylinder arrangement direction as shown in FIGS. 2 to 4. A first cooling water passage 9A extending to the other end (from the left end to the right end in FIGS. 1, 2, and 4; described below using the left and right of the same drawing), and the first cooling water passage 9A
To communicate with the cylinder head 8 at the left end side position thereof.
The cooling water passage 9A is divided into a second cooling water passage 9B that extends to the right end in the cylinder head 8 along the first cooling water passage 9A while surrounding the cooling water passage 9A with the partition wall.

The partition walls are side partition walls 11, 1 partitioning both sides of the first cooling water passage 9A in a direction orthogonal to the cylinder arrangement direction.
1, and a ceiling side partition wall 14 that partitions the upper side,
Both are integrally formed with the cylinder block 8. Each of the side partition walls 11 includes outer walls 10, 10 of the intake ports 5, 5 that are adjacent to each other in the cylinder arrangement direction, and outer walls 10, 10 of the exhaust ports 6, 6 that are adjacent to each other.
The outer walls 10 are formed so as to be connected to each other and are integrally formed. In addition, the ceiling side partition wall 14 includes the tops of the side partition walls 11 and the outer walls 1 of the intake port 5 and the exhaust port 6 facing each other in each cylinder 4.
0 and 10 are arranged so as to be connected to each other, and are integrally formed with the side partition walls 11 and the outer walls 10.

And these partition walls 11 and 14 and the top part 4 of each cylinder 4
Since a and the outer walls 10 are continuous with each other, the first cooling water passage 9A has the top surface 4a of each cylinder 4 and the outer walls 10 of the intake port 5 and the exhaust port 6 facing each other in each cylinder 4, It is partitioned and formed so as to extend in the cylinder arrangement direction through a portion directly above each cylinder 4 having the highest heat load, which is sandwiched between the portions 10 and 10.

The second cooling water passage 9B serves to cool the inside of the cylinder head 8 except for the portions directly above the cylinders 4. Then, at the location where the top portion 4a of each cylinder 4 is present, there are passages 9a to 9d at some locations because of the lack of space in the cross section.
The first cooling water passage 9A is surrounded on both sides and above (see FIG. 3 (a)) in a state of being divided into two, and when it passes through the cylinder 4, it joins to form one passage 9e. (See the right half of FIG. 3 (b)). Incidentally, FIG. 3 (b)
As shown in the left half of FIG. 2, the plug hole 13 into which the spark plug (not shown) is inserted is branched into the passage 9f, and then merges as described above.

On the other hand, the right end of the first cooling water passage 9A is the cooling water inlet 1
The cooling water introduction port 12 and the bottom portion of the radiator 1 are communicated with each other by a cooling water introduction passage 19 (see FIG. 1). Further, a cooling water discharge port 15 is arranged at the right end of the second cooling water passage 9B, and the right end of the second cooling water passage 9B is communicated with the water jacket of the cylinder block 7 by the cooling water discharge port 15. ing. The left end position of the water jacket of the cylinder block 7 and the top of the radiator 1 are connected to each other by a cooling water return passage 16.

Reference numeral 17 in FIG. 1 is a switching valve with a thermostat interposed in the cooling water return passage 16, and 18 is a bypass passage connecting the switching valve 17 and an intermediate position of the cooling water introduction passage 19 to the engine main body 3 If the temperature of the cooling water returned from the radiator 1 to the radiator 1 is, for example, 80 ° C. or lower, the cooling water is not returned to the radiator 1 and the bypass passage 18
It can be supplied to the engine main body 3 via the engine to accelerate warm-up.

In the embodiment having the above-described structure, the cooling water radiated by the radiator 1 is first introduced by the water pump 2 directly from the right end of the first cooling water passage 9A of the cylinder head 8 to the left end as indicated by an arrow M in FIG. Shed in the direction. This first
The cooling water passage 9A is partitioned by partition walls 11 and 14 so as to pass through a portion sandwiched between outer walls 10 and 10 of intake / exhaust ports 5 and 6 which face each other directly above each cylinder 4 and above each cylinder top 4a. Therefore, the cooling water in the coldest state absorbs the highest heat load in the cylinder head 8.
Only the portion directly above each cylinder 4 between the exhaust ports 5 and 6 can be preferentially and sufficiently cooled. As a result, the cooling efficiency in the place where the heat load in the cylinder head 8 is high is
This can be remarkably improved as compared with the case where the cooling water is made to flow over the entire water jacket in the cylinder head 8.

Moreover, at this time, since the ceiling side partition wall 14 partitions the upper side of the first cooling water passage 9A from the second cooling water passage 9B, only the portion directly above the cylinder 4 between the intake / exhaust ports 5 and 6 is separated. Cooling can be further promoted.

Then, after returning to the left end position of the first cooling water passage 9A, flowing into the second cooling water passage 9B and flowing to the right end in the direction of arrow N, the parts other than the immediately upper portion of each cylinder 4 are cooled, After the cooling water discharge port 15 flows into the water jacket of the cylinder block 7 and moves in the water jacket in the direction of arrow P to cool the cylinder block 7, the radiator 1 is passed through the cooling water return passage 16.
Returned to.

In addition, in the above embodiment, the first cooling water passage and the second cooling water passage
By the side partition walls 11 for partitioning the cooling water passage, the outer walls 10, 10 of the intake / exhaust ports 5, 6 of each cylinder 4 are integrally connected in the cylinder arrangement direction. Since the side partition walls 14 are also integrally connected in the direction orthogonal to the cylinder arrangement direction, the outer walls 1 of the intake / exhaust ports 5 and 6 independently arranged for each cylinder 4 are arranged.
0 and 10 can be integrated via the partition walls 11 and 14. As a result, the outer walls 10, 10 of the intake / exhaust ports 5, 6 can be firmly supported, and the rigidity of the entire cylinder head 8 can be improved. As a result, it is possible to make the structure stronger against the impact and heat due to the explosion in each cylinder 4.

FIG. 5 shows an example in which the circulation paths of the cooling water are different, and the water jacket 9 in the cylinder head 8 and the water jacket in the cylinder block 7 are completely separated,
The cylinder head 8 and the cylinder block 7 are cooled independently of each other. In this case, the cooling water discharge port 15 of the second cooling water passage 9A is connected to the cooling water return passage 16 without communicating with the water jacket of the cylinder block 7. The bypass passage 18 and the thermostatted valve 17 for warming up the engine are provided in the cooling water at a position downstream of the position where the cooling water after the cooling of the cylinder head 8 and the cooling of the cylinder block 7 join. It is provided in the return passage 16.

Even when such a cooling path is adopted, the cooling efficiency in the vicinity of the top of each cylinder having a high heat load in the cylinder head 8 by the first cooling water passage 9A is improved, and the partition wall 1
1, 14 to improve the rigidity of the cylinder head 8,
It can be obtained as in the case of FIG.

The present invention is not limited to the above embodiment,
It also includes various other modifications. That is,
In the above embodiment, the ceiling side partition wall 14 is provided as the partition wall, but the present invention is not limited to this, and for example, the ceiling side partition wall 1
4 may be removed and the entire upper portion of each cylinder top 4a may be used as the first cooling water passage. Even in this case, as compared with the case where the cooling water is made to flow all over the water jacket 9 of the cylinder head 8 simultaneously, the cooling efficiency is improved by first making the cooling water flow only to the upper portion of each cylinder top 4a by the first cooling water passage, And the cylinder head 8 by each side partition wall 11
The rigidity of can be improved.

Further, in the above-described embodiment, the case where the cooling water from the radiator 1 is directly supplied to the first cooling water passage 9A of the cylinder head 8 is shown, but the present invention is not limited to this and, for example, although not shown, the cooling water from the radiator is not shown. May be first supplied to the water jacket of the cylinder block, flow through the water jacket, and then indirectly supplied to the first cooling water passage of the cylinder head. Even in this case, as compared with the case where the cooling water that has passed through the cylinder block is made to flow to the entire water jacket of the cylinder head, the cooling water is first made to flow to a location having a high heat load by the first cooling water passage, so that the thermal efficiency is improved. Can be achieved.

As described above, according to the cooling structure for a cylinder head of the present invention, the inside of the water jacket of the cylinder head is
A partition wall is provided between a first cooling water passage and a second cooling water passage surrounding the passage, which cools a portion sandwiched between the outer walls of the intake / exhaust ports facing each other and the top portion of each cylinder, in particular, a portion having a high heat load. Since the partition is formed, it is possible to preferentially cool the upper part of the cylinder having a high heat load, and improve the cooling efficiency in the upper part of the cylinder as compared with the case where the cooling water is flowed over the entire water jacket. be able to. As a result, the occurrence of cracks and the like can be prevented, and a cylinder head with high durability against heat load can be obtained.

Further, the partition walls for partitioning the first cooling water passage are arranged so as to connect the outer walls of the intake / exhaust ports adjacent to each other, and are formed integrally with the outer walls of the intake / exhaust ports. The rigidity of the cylinder head can be increased, and the cylinder head can be mechanically strong.

As a result, the rigidity of the cylinder head itself can be increased while improving the cooling efficiency at a location in the cylinder head where the heat load is high.

[Brief description of drawings]

FIG. 1 is a schematic view of an engine cooling system including a cooling structure for a cylinder head according to the present invention, and FIG.
II sectional view taken along the arrow, FIG. 3A is a sectional view taken along the line III-III in FIG. 2, and FIG. 3B is a sectional view taken along the line IV-IV in FIG. 2 is a sectional view taken along the line VV of FIG. 2, and FIG. 5 is a system diagram of a cooling structure of a cylinder head in different cooling paths. 1 ... radiator, 3 ... engine body, 4 ... cylinder,
4a ... Cylinder top, 5 ... intake port, 6 ... exhaust port, 8 ... cylinder head, 9 ... water jacket, 9A ... first cooling water passage, 9B ... second cooling water passage, 10 ... ... Outer wall of intake or exhaust port, 1
1 ... Side partition wall (partition wall), 14 ... Ceiling side partition wall (partition wall).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taku Fuse 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References: 61-122322 (JP, U)

Claims (1)

[Claims] 1. A cooling structure for a cylinder head of a cross-flow type multi-cylinder engine, wherein an inner space of a water jacket in the cylinder head extends from one end to the other end in the cylinder head in a cylinder arrangement direction by a partition wall. Partitioned into a first cooling water passage and a second cooling water passage that communicates with the first cooling water passage at the other end side position of the cylinder head and extends along the first cooling water passage to one end in the cylinder head. The first cooling water passage is partitioned by the partition wall so as to pass through a portion sandwiched between the top surface of the top of each cylinder and the outer wall portions of the intake port and the exhaust port facing each other in each cylinder. On the other hand, the second cooling water passage is arranged so as to surround the first cooling water passage through the partition wall, and the partition walls are adjacent to each other in the cylinder arrangement direction. The outer walls of the intake ports and the outer walls of the exhaust ports adjacent to each other in the cylinder arrangement direction are integrally formed with the respective outer walls, and the first cooling water passage is formed from one end side position of the cylinder head. The cooling water from the radiator is connected to the radiator so as to be introduced into the first cooling water passage, while the cooling water is connected to the second cooling water passage.
The cooling water passage extends from the position on the one end side of the cylinder head to the second position.
A cooling structure for a cylinder head, wherein cooling water in a cooling water passage is connected to the radiator so as to be returned to the radiator.