JPS5856353Y2 - Internal combustion engine cylinder liner cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling device for an internal combustion engine, and particularly to a cooling device for preventing overheating of the upper part of a cylinder liner of a reciprocating internal combustion engine.

It is well known that in internal combustion engines such as diesel engines, a cooling water distribution jacket is provided inside the cylinder block to remove the thermal load caused by overheating of various parts during engine operation. The cooling jacket provided on the cylinder liner, which is subjected to the largest thermal load, usually has a structure as shown in FIG.

That is, a cylindrical ice coat part 3 having approximately the same width is formed in the area surrounding the cylinder liner 2 of the cylinder block 1, while the upper part of the ice coat part 3 is provided with cooling water discharged from the jacket of the cylinder block 1. A communication hole 4 is provided for supplying cooling water to a jacket (not shown) on the cylinder head side, and an enlarged portion for guiding cooling water from the ice jacket part to the communication hole 4;
That is, a hollow portion 5 is formed.

However, in a jacket with such a conventional structure, the volume of the jacket is large in the upper part of the cylinder liner where the heat load is greatest, so only the main flow of cooling water actively circulates as shown in the figure. The cooling water of the cylinder stagnates, resulting in a decrease in the cooling efficiency of the liner, resulting in a large thermal load on the upper part of the cylinder liner.

This tendency is particularly noticeable in a central pre-combustion chamber engine as shown in FIG. Front chamber 9 for
In an internal combustion engine equipped with a pre-combustion chamber 9 consisting of a rear chamber 9a and a rear chamber 9b, an ejection hole 10 is provided in the lower part of the front chamber 9a toward the side wall of the cylinder liner in order to eject combustion gas while creating a vortex within the cylinder. Because of this, hot gas directly impinges on the inner wall of the liner during engine operation, causing local heating of the upper part of the liner 2. There is a problem in that it has a large adverse effect on the wear of C and piston rings, and an improvement has been desired.

The present invention was devised to solve the problems inherent in conventional internal combustion engines as described above. A communication passage is provided at the top of the jacket, one end of which is open, and the other end of which is open to the cooling water communication hole leading to the cylinder and the RAD side jacket. It is characterized by a structure in which a sag is formed so that water can swirl around the liner and flow in.

Hereinafter, specific details of the present invention will be explained with reference to embodiments shown in the accompanying drawings.

FIGS. 3 and 4 show the main parts of the device of the present invention. In the figures, 13 is a cooling water distribution jacket formed between the cylinder block 11 and the cylinder liner 12. The jacket, except for its upper part, is a water jacket part 13a with a large gap.

The upper part of the jacket 13, that is, the piston is
The vicinity of the position corresponding to the height of the top ring when it reaches the second dead center is a narrow part with a smaller cross-sectional area over the entire circumference compared to the gap of the swimsuit part 13H, which forms a feature of the present invention. There is.

Note that the gap T in the narrowly constricted portion 13b of the jacket 13 is preferably set to about 4 to 6% of the cylinder bore (inner diameter), that is, if the cylinder bore is 13Q mm, it is preferably set to about 5 rnin. Even if the water flow rate increases and the cooling capacity increases, on the other hand, cavitation occurs, leading to unfavorable results.

Further, the longitudinal length L of the narrowly constricted portion 13b of the jacket 13 is approximately 13 to 13 mm relative to the stroke length of the piston.
For an engine with a stroke length of 15 Qmm, the stroke length is preferably about 20%, for example, about 20 to 3 Qmm, and if it is longer than this, cavitation may occur as described above, which is undesirable.

Reference numeral 14 denotes a horizontally elongated rectangular or elliptical communication passage connected to the uppermost end of the jacket 13 and formed substantially horizontally, and a cooling passageway 14 communicating with a jacket on the cylinder head side (not shown) is located at the back of the communication passage 14. Water communication holes 15 are vertically drilled and form a series of flow paths communicating from the jacket 13 to the cylinder head.

Note that it is effective to machine the communication passage 14 so that air bubbles generated in the jacket 13 can easily flow out, and to form it continuously at the uppermost end of the jacket 13 where possible.

On the other hand, wide openings are provided on the left and right sides of the jacket 13 side opening of the communication passage 14 so that when the cooling water passes through the communication passage 14 and flows out, it can swirl so that it can easily flow into the communication passage at the upper part of the liner 12. A notch, that is, a slotted portion 16 is provided.

When a plurality of communication passages 14 are arranged at uneven intervals around the liner 12 as illustrated in FIG.
It is preferable to provide opposing groove portions 16 whose size is proportional to the distance between the four members, in order to generate a swirling flow in the cooling water over the entire circumference of the liner 12.

The present invention has the above-mentioned configuration. During engine operation, the cooling water rising inside the jacket passes through the narrow gap provided at the top of the jacket I, increasing the flow velocity, and then flowing through the communication passage provided in the cylinder block. When flowing in, a swirling flow is generated by the hollow part, improving cooling efficiency in the upper part of the jacket, and effectively preventing overheating of the liner.

As shown in Figures 3 and 4, when the device of the present invention was applied to an actual internal combustion engine and tested, the liner temperature was approximately 30% lower than that of a cooling device consisting of a conventional jacket.
It was confirmed that the temperature was reduced.

This proves the effectiveness of the device of the present invention.

As described above, according to the device of the present invention, by setting the narrow part at the upper part of the jacket, the cooling efficiency in a part of the liner can be greatly increased.
When used in a central preheat combustion type internal combustion engine that tends to be subjected to a large thermal load, its cooling efficiency makes it possible to sufficiently suppress local overheating of the upper part of the liner, improving the performance and durability of the internal combustion engine. It has a very noticeable effect on improvement.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional side view of the main part showing the jacket shape of a conventional liquid-cooled internal heat engine, Fig. 2 is a sectional view of the main part of a pre-combustion chamber engine, and Fig. 3 is a jacket and a side view of the main part of a cooling device according to the present invention. A cross-sectional view of a main part showing an example of a cooling water flow passage, FIG.
It is a sectional view taken along the line XX in the figure. 11... Cylinder block, 12...
Cylinder liner, 13... Jacket, 13
b...jacket" 2nd part, small part, 14...
...Communication passage, 15...Communication hole, 16...
... Nusumi club.

Claims (1)

[Scope of utility model registration request] 1. In an internal combustion engine provided with a cooling water distribution jacket between a cylinder liner and a cylinder block, the upper end of the jacket is configured to have a smaller cross-sectional area than the lower part over the entire circumference of the liner, and the upper end is located at the uppermost end of the jacket. The internal combustion engine has a communication passage leading to a cooling water communication hole that communicates with the cylinder head side jacket, and an inlet of the communication passage is provided with a slotted portion through which cooling water swirls around the liner and flows in. Engine cylinder liner cooling system. 2. The cylinder liner cooling device for an internal combustion engine according to claim 1, wherein the gap between the cylinder liner at the upper end of the jacket and the cylinder block is 4 to 6% of the cylinder bore. 3. The gap between the cylinder liner at the upper end of the jacket and the cylinder block is 13 to 20% of the piston stalk length.
A cylinder liner cooling device for an internal combustion engine according to claim 1 or 2, which is a utility model. 4. The cylinder liner cooling device for an internal combustion engine according to claim 1, 2, or 3, wherein the size of the hollow portion is proportional to the distance between the communicating passages.