JPH06185402A - Cooling device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve both of productivity and cooling efficiency in a cooling device which cools an internal combustion engine by providing circulation of cooling water in a water jacket. CONSTITUTION:In a cooling device for an internal combustion engine in which a water jacket for a cylinder block 1 is formed by inserting a cooling pipe 3 therein in casting, communication holes 13 which communicate a cylinder block top deck with a cooling pipe 3, which is inserted in the water jacket in casting, in the axial direction of the cylinder are formed adjacent to a cylinder bore of the cylinder block 1.

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 an internal combustion engine, and more particularly to a cooling device for an internal combustion engine that cools the internal combustion engine by circulating cooling water in a water jacket.

[0002]

2. Description of the Related Art Generally, an engine mounted on a vehicle employs a water-cooling type cooling device, in which a cylinder head is provided on a cylinder block via a head gasket. A water jacket through which cooling water passes is formed in the cylinder block and the cylinder head. The cooling water is urged by the water pump to circulate in the engine to cool the engine, and also to cool the engine to raise the temperature. The cooling water is introduced into the radiator and cooled.

In order to manufacture the cooling device as described above, it is necessary to form a water jacket on the cylinder block. Conventionally, when forming a closed deck type cylinder block by high pressure die casting, it is difficult to form a water jacket using a sand core,
Also, the cost will increase. Therefore, an open deck type cylinder block has been generally used in which a water jacket is formed by casting a die from the cylinder block top deck. However, since the rigidity of an open deck cylinder block decreases, a closed deck is preferable when trying to obtain a predetermined rigidity.

Therefore, a structure has been proposed in which the water jacket is formed of a pipe (Shokai Sho-60-17192).
No. 1). With this structure in which the water jacket is formed of a pipe, it is not necessary to form the water jacket directly on the cylinder block, so the cylinder block can be easily manufactured and the closed core can be easily closed without using a sand core. It can be a deck type cylinder block.

[0005]

However, when the pipe is arranged along the outer circumference of the cylinder, a bent portion is inevitably generated because the cylinder bore has a cylindrical shape. The minimum value of the bending radius (R) that secures the water channel is 1.5 x D to 2 x D
(D is the diameter of the pipe), and it is difficult to dispose the pipes, which serve as water channels, between the cylinder bores.

Further, if the bending radius R is reduced and the pipe is made to approach between the cylinder bores, the pipe is crushed, the flow passage area is significantly reduced, and the flow of the cooling water is stagnated. When the flow of the cooling water is stagnant in this way, a portion with good cooling efficiency and a portion with poor cooling efficiency occur in the cylinder block, and the temperature distribution in the cylinder block becomes uneven. As a result, the cylinder block is deformed due to the difference in temperature distribution, and due to poor roundness of the cylinder bore, lubricating oil flows into the combustion chamber, resulting in deterioration of oil consumption.

The present invention has been made in view of the above points, and by forming a water jacket by casting a pipe, and forming a communication hole for communicating the pipe in the vicinity of the bored bores, An object of the present invention is to provide a cooling device for an internal combustion engine that can improve both productivity and cooling efficiency.

[0008]

In order to solve the above problems, the present invention relates to a cooling device for an internal combustion engine, wherein a water jacket of a cylinder block is formed by casting a pipe around a cylinder bore of the cylinder block. A communication hole for communicating the cylinder block top deck and the pipe cast in the cylinder block in the cylinder axial direction is formed in the vicinity of the space.

[0009]

In the cooling device for an internal combustion engine having the above structure, the water jacket is formed by a pipe,
Since the water jacket can be formed without using the core, the cooling device can be easily manufactured.

Even in the case of a cylinder block manufactured by cast pipe stuffing, a communication hole is formed in the vicinity of the cylinder bores so as to connect the cylinder block top deck and the pipe in the cylinder axial direction. Since the passage area can be secured to an appropriate size and the position near the cylinder bores can be cooled appropriately, the temperature distribution of the cylinder block can be made uniform, and the deterioration of oil consumption caused by poor roundness of the cylinder bores can be prevented. it can.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a cross-sectional view of a cylinder block 1 (a cross-sectional view taken along a plane orthogonal to the cylinder axis) to which a cooling device according to a first embodiment of the present invention is applied, and FIG. 2 is a cross-sectional view taken along the line AA in FIG.
It is sectional drawing which follows the BB line in.

As shown in FIG. 1, a cylinder block 1 is formed with, for example, four cylinders 2a to 2d, and a cooling pipe 3 is provided at an outer peripheral position of the cylinder 2a.
.. to 2d are surrounded, and a plurality of bolt holes 5 for fixing a cylinder head or the like (not shown) to the cylinder block 1 are bored along the axial direction of the cylinders 2a to 2d. There is. Reference numeral 4 indicates an oil return hole from the cylinder head.

A plurality of cooling pipes 3 are arranged in a laminated state as shown in FIG. 2A, and cooling water is introduced into the cooling pipes 3 to cool the cylinder block 1. Has been done. This cooling pipe 3 is internally provided in the cylinder block 1 by a so-called pipe casting circumstance, in which when the cylinder block 1 is cast, the molten metal is poured into the mold while the cooling pipe 3 is arranged in the mold in advance.

FIG. 3 shows the cooling pipe 3 in a state before the cast casting is performed. The cooling pipe 3 in this state is composed of a pair of corrugated members 6 and a C-shaped member 7 that face each other, and the corrugated member 6 and the C-shaped member 7 are formed at a portion (joint portion) indicated by reference numeral 8 in the drawing. It is configured to be joined (welded) and integrated.

FIG. 4 is a diagram for explaining a method of manufacturing the cooling pipe 3 having the above structure. In order to manufacture the cooling pipe 3, the corrugated member 6 and the C-shaped member 7 are formed separately, and then the joint portions 8 are welded by combining them. First, a method of manufacturing the corrugated member 6 will be described. To manufacture the corrugated member 6, a plurality of pipes 9 are arranged side by side and then the plurality of pipes 9 are brazed to be integrated as shown in FIG. Subsequently, the integrated pipes 9 are pressed by using a predetermined die to bend the pipes 9 corresponding to the cylinders 2b to 2c as shown in FIG. The shape. Subsequently, the unnecessary portions at both ends of the plurality of curved pipes 9 are cut to manufacture the corrugated member 6 shown in FIG.

On the other hand, in order to manufacture the C-shaped member 7, as shown in FIG. 1A, after the pipe 10 is wound in a coil shape, the plurality of pipes 10 are brazed to be integrated. . Then, unnecessary parts including the pipe end are cut and removed, and the diameter is expanded to form the shape to form the C-shaped member 7 having the C shape shown in FIG.

Then, after the end portions of the corrugated member 6 and the C-shaped member 7 are flatly crushed and closed, the joint portion 8 where the corrugated member 6 and the C-shaped member 7 are butted is welded as described above. The cooling pipe 3 shown in FIGS. 4F and 4G is manufactured.

Incidentally, the corrugated member 6 at the stage before welding.
Sand 11 (or salt, which is shown as satin in FIG. 3) is filled inside the C-shaped member 7 so that the pipes 9 and 10 are not crushed by the molten metal pressure during casting.
Further, reference numeral 12 in FIGS. 4 (F) and (G) is an oil passage pipe used as a positioning member when the cooling pipe 3 is mounted on the mold.

The cooling pipe 3 having the above-described structure is mounted on the mold while being positioned on the oil passage pipe 12, and the cylinder block 1 is formed by so-called pipe casting.

As described above, since the cooling pipe 3 functioning as a water jacket is formed in the cylinder block 1 by the pipe casting, the core which was conventionally required when forming the water jacket is not required, and the cylinder block 1 is eliminated. Manufacturing is simplified. Further, since the structure of the cylinder block 1 can be a closed deck without using the sand core, the rigidity of the cylinder block 1 can be increased.

Returning to FIG. 1 again, the description will be continued. In the cylinder block 1 immediately after casting, the joint portion 8 of the cooling pipe 3 is welded with the pipes 9 and 10 crushed as described above. Further, this portion is just in the vicinity of the space between the cylinder bores. The present invention is characterized in that a communication hole 13 for communicating the pipes 6 and 7 is formed by forming a hole in the vicinity of the cylinder bores, that is, in the joint portion 8 in the axial direction of the cylinders 2a to 2d. is there.

FIG. 2B is a sectional view taken along the line BB in FIG. 1, showing a section in the vicinity of the clogged bore. As shown in the figure, the plurality of pipes 6 and 7 forming the cooling pipe 3 are communicated with each other through a communication hole 13, and the cooling water flows between the pipes 6 and 7 through the communication hole 13. Has become.

Here, paying attention to the formation position of the communication hole 13, the communication hole 13 is formed in the vicinity of the clogged bore as described above. With the configuration in which the cooling pipe 3 is simply incorporated into the cylinder block 1, it is difficult to bring the cooling pipe 3 sufficiently close to the cylinders 2a to 2d at the positions near the cylinder bores, and the cooling pipe 3 is forcibly forced to the cylinders 2a to 2d. When trying to approach 2d, the cooling pipe 3 is crushed, the flow passage area is significantly reduced, the flow of the cooling water is stopped, and the temperature distribution in the cylinder block becomes non-uniform.

However, even if the cylinder block 1 is manufactured by cast pipe stuffing by forming the communication hole 13 for communicating the respective pipes 6 and 7 constituting the cooling pipe 3 as in the present invention, the vicinity of the cylinder bores. A communication hole 13 that communicates the cooling pipe 3 in the cylinder axial direction is formed at the position, and the cooling water flowing in the communication hole 13 can also efficiently cool the position between the cylinder bores. Therefore, the temperature distribution of the cylinder block 1 can be made uniform,
It is possible to prevent deterioration of oil consumption caused by poor roundness of the cylinder bore 1.

As described above, when the cylinder bore 1 is cast, the cooling pipe 3 is filled with the sand 11, but the communication hole 13 also functions as a hole for removing the sand 11. At this time, since the cooling pipe 3 is cast in a sealed state, the molten metal does not enter the cooling pipe 3 during casting, and the sand 11 in the cooling pipe 3 does not contain resin. Even if it is a hole for extraction, the communication hole 13 can have a small diameter dimension (that is, a diameter dimension considering only cooling).

5 to 7 show a cylinder block 20 to which a cooling device according to a second embodiment of the present invention is applied. 6 shows a cross section taken along the line CC of FIG. 5, and FIG. 7 shows a cross section taken along the line DD of FIG. The same components as those of the cylinder block 1 according to the first embodiment described with reference to FIGS. 1 to 4 are designated by the same reference numerals and the description thereof will be omitted.

The cooling device shown in each drawing is characterized by having a middle deck structure by forming a jacket (groove) 21 on the upper surface 20a of the cylinder block 20. Cooling water also flows into the jacket (groove) 21, and the communication hole 13, which is a feature of the present invention, is formed in the vicinity of the bores, which is similar to the cylinder block 1 according to the first embodiment. Has been done.

In the cylinder block 20 having the above-mentioned structure, the cooling pipe 3 has the jacket 2 as shown in FIG.
It is arranged at the lower part of 1. Therefore, in the cylinder block 20, the cooling water flowing in the jacket 21 and the cooling water flowing in the cooling pipe 3 cooperate to cool the cylinder block 20. As described above, the present invention can be applied to the cylinder block 20 having the middle deck structure, and the same effect as that of the cylinder block 1 according to the first embodiment can be obtained.

In addition to this, in the cylinder block 20 according to the second embodiment, since the jacket 21 is formed by a mold, it is necessary to form the biting part 22 that deeply bites between the bores shown in FIG. Therefore, the cooling efficiency can be further improved.

Further, at the time of casting, since the jacket forming mold part formed in the mold for forming the jacket 21 is inserted into a deep position between the cylinder bores (indicated by reference numeral 23 in FIG. 7), the casting is performed. Sometimes cooling pipe 3
It is possible to prevent the deformation of the cooling pipe 3 by performing the function of holding the cooling pipe 3.

[0031]

As described above, according to the present invention, since the water jacket can be formed without using the sand core by forming the water jacket with the pipe, the cooling device can be easily manufactured. Even if the cylinder block is manufactured by casting a pipe, a communication hole is formed at a position near the cylinder bores, and cooling water flowing in the communication hole can also cool a position near the cylinder bores. Therefore, the temperature distribution of the cylinder block can be made uniform, and the deterioration of the oil consumption caused by the poor roundness of the cylinder bore can be prevented.

[Brief description of drawings]

FIG. 1 is a transverse sectional view of a cylinder block (a sectional view taken along a plane orthogonal to a cylinder axis) to which a cooling device according to a first embodiment of the present invention is applied.

2A is a sectional view taken along the line AA in FIG.
(B) is a cross-sectional view taken along the line BB in FIG. 1.

FIG. 3 is a diagram showing a cooling pipe in a state before performing pipe casting.

FIG. 4 is a drawing for explaining the manufacturing method of the cooling pipe.

FIG. 5 is a horizontal cross-sectional view (cross-sectional view taken along a plane orthogonal to the cylinder axis) of a cylinder block to which a cooling device according to a second embodiment of the present invention is applied.

6 is a cross-sectional view taken along the line CC of FIG.

7 is a cross-sectional view taken along the line DD in FIG.

[Explanation of symbols]

 1,20 Cylinder block 2a-2d Cylinder 3 Cooling pipe 6 Corrugated member 7 C-shaped member 8 Joining part 9,10 Pipe 11 Sand 12 Oil passage pipe 13 Communication hole 21 Jacket 22 Biting part

Claims (1)

[Claims] 1. A cooling device for an internal combustion engine, wherein a water jacket of a cylinder block is formed by casting a pipe around the cylinder block, wherein the cylinder block top deck and the cylinder block are cast at positions near the cylinder bores of the cylinder block. A cooling device for an internal combustion engine, characterized in that a communication hole for communicating the enclosed pipe in the cylinder axial direction is formed.