JP2000130252A - Cooling device for siamese cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the cooling device of a Siamese cylinder which can cool the part near the head of a continuous thick wall strongly and intend the relative minimizing and lightening of a multicylidner engine and the large outputting of the engine. SOLUTION: A cylinder jacket 8 is formed so as to surround a Siamese cylinder 2 and a water road is formed on the part 4a near the head of the continuous thick wall 4 of the Siamese cylinder 2. The water road is provided with right/left jacket communication roads 12.12 formed vertically so as to connect the cylinder jackets 8.8 positioned on both right/left sides of the continuous thick wall 4 with a head jacket 22 and a sideways cooling water road 15 for communicating right/left jacket communicating passages 12.12. The boss parts 5, 5 for tightening the cylinder head are formed continuously on both right/left sides of the continuous thick wall 4 and also respective jacket communication roads 12.12 are positioned inside the boss parts for tightening their respective cylinder heads 5, 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a siamese cylinder of a multi-cylinder engine. Provide something that can be improved.

[0002]

2. Description of the Related Art In recent years, the interval between cylinder bores has to be narrowed to reduce the size and weight of a multi-cylinder engine, or the cylinder bore has to be increased by increasing the cylinder bore to increase the engine output by increasing the displacement. Siamese cylinders with as thin a wall as possible have come to be used. As this kind of prior art, for example, Japanese Patent Publication No. Sho 56
No. 42744 (hereinafter referred to as Conventional Example 1).
Or Japanese Unexamined Utility Model Publication No. 59-68155 (hereinafter referred to as Conventional Example 2).

FIG. 6 shows a conventional example 1, FIG. 6 (A) is a longitudinal sectional view of a main part of a siamese cylinder, and FIG.
FIG. 6A is a cross-sectional plan view taken along line BB in FIG. 6A, and FIG. 6C is a perspective view of a water channel forming member cast into a head-side portion of the continuous wall portion of the siamese cylinder. In Conventional Example 1, a plurality of cylinders 3 are arranged in a cylinder block 1 in front and rear,
The siamese cylinder 2 is formed by connecting the adjacent cylinders 3 and 3 with the continuous wall portion 4, a cylinder jacket 8 is formed so as to surround the siamese cylinder 2, and a water channel forming member 10 is formed on the continuous wall portion 4. It is cast. As shown in FIGS. 6 (A), 6 (B), and 6 (C), the water channel forming member 10 includes a vertically long and flat cooling water channel 15 in a side view of a vertical section, and cylinder jackets at both left and right ends of the head-side portion 4a. The cooling water passage 15 communicates with the cooling water passage 15.

[0006] As shown in FIG. 6 (B), the cylinder jackets 8.8 are connected to the head-side portion 4 of the continuous wall portion 4.
The cooling water, which is located on both left and right outer sides of a and flows in from one side of the cooling water passage 15, flows through the cooling water passage 15 to cool the head-side portion 4a. In addition,
Bosses 5.5 of a pair of right and left bolts 6 for fastening a cylinder head (not shown) are connected to the cylinder jacket 8.
・ It is located outside of 8. Here, the projecting locking portions 14a, 14 protruding from both right and left ends of the water channel forming member 10 are provided.
“b” is for securely fixing the water channel forming member 10 to the core when the cylinder jacket core is manufactured.

FIG. 7 shows a second conventional example. FIG. 7A is a longitudinal sectional view of a main part of a siamese cylinder, and FIG.
7A is a cross-sectional plan view taken along line BB in FIG. 7A, and FIG. 7C is a perspective view of a water channel forming member cast into a head-side portion 4a of the continuous wall portion 4 of the siamese cylinder. As shown in FIGS. 7 (A), 7 (B), and 7 (C), the water channel forming member 10 includes a cooling water channel 15 communicating the left and right cylinder jackets 8 of the continuous wall portion 4 and a left and right cooling water channel 15. A pair of left and right jacket communication passages 12, 12 located at both ends and communicating with the cooling water passage 15;
And a pair of left and right cooling water introduction portions 13, 13 which are located toward the respective cylinder jackets 8.

The cooling water flowing in from the cooling water introduction portions 13 flows through the cooling water passage 15 and the head-side portion 4a through the jacket communication passages 12.
Out of the head jacket (not shown) located on the upper side of the continuous wall portion, and cools the head-side portion 4a of the continuous wall portion 4 during that time. The cylinder head fastening bosses 5 located on the left and right of the head leaning portion 4a of the continuous wall portion 4 are located outside the cylinder jackets 8.8, as in the first conventional example.

[0007]

In the conventional example 1, since the left and right ends of the cooling water passage 15 and the projecting locking portions 14a and 14b project into the cylinder jackets 8.8, the cooling water channel 15 extends along the cylinder outer peripheral surface (3a). This impedes the smooth flow of the cooling water that is trying to flow, and prevents the cooling water from flowing into the cooling water passage 15. For this reason, there is a disadvantage that the head-side portion 4a of the continuous wall portion 4 cannot be cooled strongly. Moreover,
The cooling water channel 15 of the water channel forming member 10 is vertically long in a longitudinal side view.
Because of the flatness, the mechanical strength of the cooling water passage 15 is low, and the durability to distortion during drilling of the cylinder bore is inferior. Further, since the left and right cylinder head fastening bosses 5.5 are located outside the cylinder jackets 8.8, the distance between the left and right head bolts 6.6 becomes large, and the cylinder 3
Cannot be fastened uniformly and strongly along the circumferential direction.

Further, in the conventional example 2, each jacket communication path 1
The cooling water introduction part 13 is formed by cutting out the lower part of the cylinder constituting
However, since the frontage of the cooling water introduction portion 13 is small, a large amount of cooling water cannot be smoothly introduced into the cooling water passage 15, and the head-side portion 4a of the continuous wall portion 4 has strong strength. Has the disadvantage that it cannot be cooled. Moreover, since the cooling water passage 15 is vertically long and flat like the conventional example 1,
Poor strain durability when drilling cylinder bores. further,
Since the left and right cylinder head fastening bosses 5, 5 are located outside the cylinder jacket 8.8, the interval between the left and right head bolts 6, 6 is increased, and the cylinder 3 is uniformly and circumferentially arranged. There is a drawback that it cannot be strongly engaged.

In other words, in each of Conventional Example 1 and Conventional Example 2, the head-side portion 4a close to the combustion chamber cannot be cooled powerfully and the heat radiation ability is low, so that the air utilization rate cannot be improved, and hence the engine cannot be improved. Output cannot be increased. That is, although the piston ring is cooled via the cylinder wall, if the heat dissipating ability of the head-side portion 4a is low, the top ring is separated from the top surface of the piston by a certain distance from the viewpoint of preventing seizure of the piston ring. I have to install it. This means that a ring-shaped dead space which does not contribute to combustion occurs on the outer periphery of the piston top. Therefore, the air utilization cannot be improved, and the output of the engine cannot be increased. In addition, the strain durability during drilling of the cylinder bore and during engine operation is poor.

A diesel engine has a high compression ratio and requires a gas seal pressure of about 900 kg / cm ² or more. 5 is so large that the cylinder 3 cannot be fastened uniformly and strongly along the circumferential direction.
The gas seal pressure cannot be sufficiently increased. In particular, in recent years, it has been demanded to further reduce the size and weight and increase the output of the engine.
Cannot meet these demands satisfactorily because of the above disadvantages.

The present invention has been made in view of the above circumstances, and further improves the air utilization rate by cooling the head-side portion of the continuous wall portion more strongly and positioning the top ring higher. It is an object of the present invention to further reduce the size and weight of a multi-cylinder engine and to improve the output of the engine, and to improve the distortion durability during drilling of a cylinder bore and during operation of the engine.

[0012]

The basic structure of the present invention is configured as follows. A cylinder jacket 8 is formed so as to surround the siamese cylinder 2, and a water passage is formed in the head-side portion 4 a of the continuous wall portion 4 of the siamese cylinder 2. The water passages have left and right jacket communication passages 12, 12 formed vertically so as to communicate the cylinder jackets 8.8 and the head jacket 22 located on both left and right sides of the continuous wall portion 4, and the left and right jacket communication passages. A cooling water passage 15 is provided which communicates with the jacket communication passages 12.

According to a first aspect of the invention, there is provided a siamese cylinder cooling device having the above-described basic configuration, which has the following characteristic configuration. Cylinder head fastening bosses 5 are formed continuously on both left and right sides of the continuous wall portion 4, and the jacket communication passages 12 are formed inside the cylinder head fastening bosses 5. Characterized by that

According to a second aspect of the present invention, in the cooling apparatus for a siamese cylinder according to the first aspect, the cooling water passages 15 located in the head-side portion 4a between the left and right cylinder head fastening bosses 5 are provided. Are divided into upper and lower sections.

According to a third aspect of the present invention, in the cooling device for a siamese cylinder according to the first or second aspect, an upper edge of the cooling water passage 15 is formed to have an upward and downward slope. And

According to a fourth aspect of the present invention, there is provided a cooling apparatus for a siamese cylinder according to any one of the first to third aspects, wherein each of the jacket communication paths 12.
2, cooling water introduction portions 13, 13 opening toward the cylinder jackets 8, 8 are provided, and the cooling water introduction portions 13, 13 are expanded along the cylinder outer peripheral surface 3 a. Features.

According to a fifth aspect of the present invention, there is provided the cooling apparatus for a siamese cylinder according to any one of the first to fourth aspects, wherein the pair of jacket communication passages 12 is provided.
12 is characterized in that the inner opening distance d is set smaller than the left and right dimension D of the continuous wall portion 4.

[0018]

According to the first aspect of the present invention,
In the cooling device for a siamese cylinder having the above-mentioned basic configuration, the boss portions 5,5 for fastening the cylinder head are continuously formed on both right and left sides of the continuous wall portion 4, and the jacket communication passages 12,12 are formed by Since it is located inside the cylinder head fastening bosses 5,5, the thick portions on both the left and right sides of the head shift portion 4a can be cut out to increase the hole diameter of the jacket communication passages 12,12. Thereby, a large amount of cooling water can be circulated to enhance the cooling performance. That is, the cooling water in the cylinder jackets 8.8 flows to the head jacket 22 through the above-mentioned water channel. During this time, much of the cooling water flows through the cooling water passage 15 to cool the head-side portion 4a strongly. And since the piston ring can cool the piston ring powerfully through the cylinder wall, the top ring is brought as close as possible to the top surface of the piston, and the ring-shaped dead space that does not contribute to combustion on the outer periphery of the piston top is reduced as much as possible and air The utilization rate can be improved. Accordingly, it is possible to eliminate the sticking of the top ring due to the carbonization of the unburned portion of the fuel and the lubricating oil.

With the top ring as close as possible to the top surface of the piston, the position of the piston pin is made as close as possible to the top surface of the piston, and the swinging dimension of the crankshaft can be lengthened accordingly. , Without changing the physique (height) of the connecting rod or engine, piston stroke,
As a result, the displacement can be increased. That is, it is possible to reduce the size of the multi-cylinder engine and increase the output of the engine.

Conversely, when the piston stroke is not changed, the connecting rod can be set longer as much as the position of the piston pin is brought closer to the top surface of the piston, so that the pressure on the piston side can be reduced, and as a result, the friction loss can be reduced. Also, since the head-side part can be cooled strongly,
By increasing the diameter of the cylinder bore, it is possible to increase the displacement and, consequently, the output.

According to the second aspect of the present invention, in the first aspect,
In the siamese cylinder cooling device described in
Since the cooling water passage 15 located in the head-side portion 4a between the left and right cylinder head fastening bosses 5 is divided into upper and lower stages, compared with a conventional example having a vertically long and flat cooling water passage, The mechanical strength of the cooling water passage 15 increases, and the durability against distortion during drilling of the cylinder bore and during operation of the engine increases.

According to the third aspect of the present invention, in the first aspect,
Alternatively, in the cooling device for a siamese cylinder according to claim 2, since the upper edge of the cooling water channel 15 is formed to be inclined upward and outward in the left-right direction, the cooling water boils in the cooling water channel 15 to generate steam. However, since the water vapor moves upward along the upper edge of the cooling water passage 15 which is formed upward and outward in the left-right direction and escapes to the head jacket 22 through the jacket communication passages 12, the cooling performance is maintained at a high level. .

According to the fourth aspect of the present invention, in the first aspect,
4. The siamese cylinder cooling device according to claim 1, wherein
The cylinder jackets 8.8 and 8
The cooling water introduction portions 13 and 13 are opened toward the cylinder, and the cooling water introduction portions 13 and 13 are expanded along the cylinder outer peripheral surface 3a. The cooling water smoothly flows along the outer peripheral surface 3a, and passes through the jacket communication passages 12 and 12 and the cooling water passage 15 from the cooling water introduction portions 13 and 13 that are expanded toward the cylinder jackets 8 and 8 to the head jacket 22. This cools the head-side portion 4a more strongly.

According to the invention described in claim 5, according to claim 1
5. The cooling device for a siamese cylinder according to claim 4, wherein an interval d between the inner openings of the pair of jacket communication passages 12 is set to be smaller than a left-right dimension D of the continuous wall portion 4. Therefore, the distance d between the inner openings of the jacket communication passages 12 is reduced,
Since the arrangement interval between the left and right head bolts 6 can be reduced and the number of head bolts 6 around the cylinder 3 can be increased, the cylinder 3 can be more uniformly and strongly fastened along the circumferential direction. Can be. Thereby, the gas seal pressure can be increased.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part of a vertical multi-cylinder engine provided with a siamese cylinder cooling device according to the present invention, wherein FIG. 1 (A) is a partial vertical sectional view, and FIG. 1 (B) is a partial plan view of its cylinder block. It is. FIG. 2 shows a channel forming member according to the embodiment of the present invention, and FIG.
Is a perspective view of the water channel forming member, and FIG. 2B is FIG.
FIG. 2C is a vertical cross-sectional view taken along line BB of FIG. 2, and FIG. 2C is a cross-sectional plan view taken along line CC of FIG. FIG. 3 is a longitudinal sectional view of a main part of a vertical multi-cylinder engine equipped with a siamese cylinder cooling device according to the present invention.

As shown in FIG. 3, the vertical multi-cylinder engine E has a cylinder head 20 fixed on a cylinder block 1 integrally formed with a crankcase with a head bolt 6, and a cylinder formed on the cylinder block 1. The jacket 8 and the head jacket 22 formed on the cylinder head 20 are communicated with each other through a large number of jacket communication holes 24 formed on portions other than the continuous wall portion 4, and the cylinder head 20 is cooled with cooling water that has cooled the cylinder block 1. It is configured to

The cooling device for a siamese cylinder according to the present invention has the same basic configuration as the first and second prior arts. That is, as shown in FIGS. 1 and 3, a plurality of cylinders 3 are arranged side by side in a cylinder block 1 and adjacent cylinders 3 are connected by a continuous wall portion 4 to constitute a siamese cylinder 2. A cylinder jacket 8 is formed so as to surround the siamese cylinder 2. A water channel forming member 10 described below is cast in the continuous wall portion 4.

Hereinafter, the characteristic configuration of the embodiment of the present invention will be described. As shown in FIG. 2, the water channel forming member 10 is formed integrally by pressing and pressing two sheet metal sheets facing each other and seam welding a contact portion.
In other words, the waterway forming member 10 includes a pair of left and right jacket communication paths 12 and 12 and the jacket communication paths 12 and 12.
, A pair of left and right cooling water introduction portions 13, 13 opening to the respective cylinder jackets 8, 8, and the left and right jacket communication passages 12, 12 and the left and right cooling water introduction portions 1.
A cooling water passage 15 communicating with the cooling water guides 3 and 13. The cooling water introduction portions 13 and 13 respectively move a pair of front and rear cooling water guide plates 14 and 14 projecting left and right along the cylinder outer peripheral surface 3a. The cooling water introduction section 13.1
A large amount of cooling water introduced from 3 is configured to flow through the cooling water passage 15 and to flow out to the head jacket 22 located above the head-side portion 4a via the jacket communication passages 12. I have.

As described above, since the water channel forming member 10 includes the non-hollow portions 11 and the cooling water channel 15 formed alternately in upper and lower stages, the mechanical strength of the cooling water channel 15 is increased. The cooling water channel 15 is vertically long
As compared with the case where the cylinder wall is formed flat, there is an advantage that the pressing force acting on the continuous wall portion 4 can be strongly counteracted during the processing of the cylinder bore or the engine operation, and the distortion durability can be increased.

A pair of left and right cylinder head fastening bosses 5
5 is formed continuously with the right and left side portions of the head-side portion 4a, and narrows the arrangement interval of the head bolts 6, 6 and uniformly and strongly fastens the cylinder 3 in the circumferential direction by the narrowed portion. It is configured to be. Although the present invention is not limited to this, a pair of left and right cylinder head fastening bosses 5, 5 are formed on the upper end wall of the cylinder block 1 by being formed continuously with the left and right sides of the head offset portion 4a. Jacket communication hole 23 and a pair of jacket communication passages 1
There is an advantage that a large amount of cooling water can be made to flow by increasing the hole diameter of 2.12.

The pair of jacket communication passages 12, 12 are located inside the boss portions 5, 5, and the cylinder block 1
And a jacket communication hole 23 formed in the upper end wall of the cylinder head 20 and the lower end wall of the cylinder head 20. Also, cooling water channel 1
The left and right dimensions d of 5 are, as shown in FIGS.
It is set smaller than the left and right dimension D of the continuous wall portion 4. As a result, the pair of jacket communication paths 12
The twelve opening inner distances d are set smaller than the left and right dimensions D of the continuous wall portion 4. Therefore, the distance between the left and right head bolts 6,6 can be reduced by the amount of the narrowing of the opening inside space d of the jacket communication passages 12,12, and the number of head bolts 6 around the cylinder 3 can be increased. Therefore, the cylinder 3 can be more uniformly and strongly fastened along the circumferential direction. Thereby, the gas seal pressure can be increased.

The above-mentioned cooling water introduction portions 13 are provided with a pair of front and rear cooling water guide plates 1 from both left and right ends of a lower cooling water passage 15.
4 ・ 14 protruding left and right, these cooling water guide plates 14 ・ 14
14 are respectively expanded and retracted along the cylinder outer peripheral surface 3a. With the above configuration, the frontage of the cooling water introduction portions 13 is formed large, and most of the cooling water is provided below the cooling water passages 15b and the jacket below the cooling water introduction portions 13 extended toward the cylinder jackets 8.8. A large amount flows into the communication passage 12, and the jacket communication passage 12
Through 12, it passes through to the head jacket 22 located above the continuous wall portion 4. In the meantime, a large amount of cooling water flows through the cooling water passage 15 and the jacket communication passages 12 and 12, and cools the head-side portion 4a strongly. As a result, the displacement of the engine can be increased, and the output can be increased.

That is, since the piston ring can be strongly cooled through the cylinder wall by strongly cooling the head-side portion 4a, the top ring is brought as close as possible to the top surface of the piston, and combustion of the outer periphery of the top portion of the piston is prevented. The ring-shaped dead space that does not contribute can be reduced as much as possible to improve the air utilization rate. In addition, the sticking of the top ring due to the carbonization of the unburned portion of the fuel can be eliminated.

Further, as the top ring is brought as close as possible to the piston top surface, the position of the piston pin is brought as close as possible to the piston top surface, and the swinging dimension of the crankshaft is lengthened accordingly. Therefore, it is possible to reduce the size of the connecting rod engine without changing its size, increase the piston stroke, and increase the displacement. Further, since the head-side portion 4a can be cooled strongly, the displacement can be increased by increasing the diameter of the cylinder bore. Furthermore, by applying the present invention to a multi-cylinder engine or the like equipped with a turbocharger, it is possible to achieve a relative reduction in size and an increase in engine output.

FIGS. 4A and 4B are schematic views illustrating the cross-sectional shape of the cooling water channel 15 of the water channel forming member 10 formed by stacking two sheet metals. FIG. 4A shows a rectangular shape, FIG. 4B shows a pentagonal shape, and FIG.
(C) shows a hexagon, (D) shows a semicircle, and (E) shows a half rectangle, and the shape is appropriately selected in consideration of the shape of the continuous wall portion 4 and the like.

FIG. 5 is a schematic view illustrating another arrangement of the cooling water passages 15 of the water passage forming member 10. FIG. 5 (A) shows a non-hollow portion 11 and cooling water passages 15 arranged alternately in multiple stages in an upper and lower direction. In order to cool the head-side portion 4a of the continuous wall portion 4 strongly, an upper cooling water passage is provided. The width of the passage 15a is larger than the width of the lower cooling water passage 15b. FIG.
In (B), the non-hollow portions 11 and the cooling water passages 15 that are alternately arranged in upper and lower stages are both formed in a downwardly arcuate shape.
FIG. 5C shows that the cooling water passage 15 has a substantially V-shape.
As in (A), the width of the upper cooling water passage 15a is larger than the width of the lower cooling water passage 15b. FIG. 5 (D)
The cooling water passages 15 arranged vertically in multiple stages communicate with the central portion of the cooling water passages 15c in a vertically oriented cooling water passage 15c. FIG. 5E is FIG.
The central part of the cooling water channel 15 similar to (C) is communicated with a vertical cooling water channel 15c. In FIG. 5 (F), the non-hollow portion 11 and the cooling water passage 15 are tilted in multiple stages up and down. In FIG. 5 (G), the cooling water passages 15 which cross each other in a substantially X-shape are arranged vertically in two stages.

According to the arrangements of FIGS. 5B to 5G,
Even if the cooling water boils in the cooling water passage 15 and steam is generated, the steam moves upward along the upper edge of each inclined cooling water passage 15 and passes through the jacket communication passages 12, 12. Since the air escapes to the jacket 22, the cooling performance is kept high.

[Brief description of the drawings]

FIG. 1 shows a main part of a vertical multi-cylinder engine provided with a siamese cylinder cooling device according to the present invention. FIG. 1 (A) is a partial vertical sectional view, and FIG. 1 (B) is a partial plan view of a cylinder block thereof. FIG.

FIG. 2 shows a channel forming member according to an embodiment of the present invention,
2A is a perspective view of the water channel forming member, FIG. 2B is a vertical sectional view taken along line BB in FIG. 2A, and FIG. 2C is a sectional view in FIG. FIG. 4 is a cross-sectional plan view taken along line CC.

FIG. 3 is a longitudinal sectional view of a main part of a vertical multi-cylinder engine including a siamese cylinder cooling device according to the present invention.

FIG. 4 is a schematic view illustrating a cross-sectional shape of a cooling channel of the channel forming member of the present invention.

FIG. 5 is a schematic view illustrating the arrangement of cooling water channels of the water channel forming member of the present invention.

6A and 6B show a conventional example 1, in which FIG. 6A is a longitudinal sectional view of a main part of a siamese cylinder of a vertical engine, and FIG. 6B is a cross section taken along line BB in FIG. FIG. 2C is a plan view, and FIG. 2C is a perspective view of a water channel forming member.

7 is a diagram corresponding to FIG. 6, showing Conventional Example 2. FIG.

[Explanation of symbols]

2 ... Siamese cylinder, 3a ... Cylinder outer peripheral surface, 4
…… Continuous wall portion, 4a… Head portion of continuous wall portion, 5
... Cylinder head fastening boss part, 8 ... Cylinder jacket, 12 ... Jet communication path, 13 ... Cooling water introduction part, 1
5: cooling water channel, 15b: upper edge of cooling water channel, 22: head jacket, D: left and right dimensions of continuous wall portion, d: inner opening interval of jacket communication passage.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasumichi Kamata 64 Ishizukitamachi, Sakai City, Osaka Prefecture Inside Kubota Sakai Factory (72) Inventor Akira Hayaya 64 Ishizukitamachi, Sakai City, Osaka Prefecture Inside Kubota Sakai Factory ( 72) Inventor Masaji Yukawa 64 Ishizukita-cho, Sakai-shi, Osaka Prefecture Inside Kubota Sakai Factory (72) Inventor Osamu Ishii 64 Ishizukita-cho, Sakai-shi, Osaka Prefecture Inside Kubota Sakai Factory (72) Inventor Kazuyoshi Morioka Sakai, Osaka 64 Ishizu-Kitamachi, Kubota Sakai Factory

Claims (5)

[Claims] 1. A cylinder jacket (8) is formed so as to surround a siamese cylinder (2), and a water channel is formed in a head-side portion (4a) of a continuous wall portion (4) of the siamese cylinder (2). The water passage has a left and right jacket communication passage (12) formed vertically so as to communicate the cylinder jacket (8.8) and the head jacket (22) located on the left and right sides of the continuous wall portion (4). .12) and a lateral cooling water channel (15) communicating with the left and right jacket communication passages (12.12). While the cylinder head fastening bosses (5, 5) are formed continuously,
The jacket communication passages (12, 12) are located inside the cylinder head fastening bosses (5, 5).
A cooling device for a siamese cylinder. 2. A cooling apparatus for a siamese cylinder according to claim 1, wherein said cooling water passage (15) located at a head-side portion (4a) between said left and right cylinder head fastening bosses (5.5) is provided. A siamese cylinder cooling device, which is divided into upper and lower sections. 3. The siamese cylinder cooling device according to claim 1 or 2, wherein an upper edge of the cooling water passage (15) is formed so as to be inclined upward and outward in the left-right direction. Cooling system. 4. The cooling device for a siamese cylinder according to claim 1, wherein the cylinder communication passages (12, 12) are provided at lower portions of the respective jacket communication passages (12, 12), respectively. A cooling water introduction part (13, 13) opening toward the air is provided, and each of the cooling water introduction parts (13, 13) is expanded along the cylinder outer peripheral surface (3a). Cooling system. 5. The cooling device for a siamese cylinder according to claim 1, wherein the interval (d) between the inner openings of the pair of jacket communication passages (12, 12) is set to the continuous thickness. A cooling device for a siamese cylinder, wherein the right and left dimensions (D) of the wall portion (4) are set to be smaller.