JPH0740652Y2 - Cooling device for internal combustion engine - Google Patents

Description

The present invention relates to a cooling device for a water-cooled internal combustion engine.

2. Description of the Related Art Conventionally, an indirect cooling device for a water-cooled internal combustion engine includes a radiator type in which the internal cooling engine is cooled by primary cooling water and the primary cooling water is cooled by an air flow, and an internal combustion engine is cooled by primary cooling water. There is a heat exchanger type in which the primary cooling water is cooled by the secondary cooling water. In addition to these, there is a direct cooling type in which the primary cooling water is passed and then the primary cooling water is drained to the outside of the internal combustion engine.

Here, in the heat exchanger type cooling device, a heat exchanger for radiating the heat of the primary cooling water that has cooled the engine to the secondary cooling water is provided. This heat exchanger is configured by bundling a large number of thin tubes through which the secondary cooling water flows at a constant interval and is arranged inside an outer tube through which the primary cooling water flows. In addition, this outer tube,
It is connected to a water jacket formed around the cylinder and the cylinder head.

Also, there is an internal combustion engine in which a silencer water jacket is formed around the silencer connected to the cylinder, and it is common to supply the secondary cooling water that has passed through the heat exchanger into the silencer water jacket. Is. Then, the secondary cooling water that cooled the primary cooling water when passing through the heat exchanger cools the silencer when passing through the silencer water jacket, and is then discharged from the silencer water jacket to the outside. It

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional heat exchanger type cooling device, in addition to the secondary cooling water pump for supplying the secondary cooling water and its piping system, the primary cooling water is forcedly circulated. A primary cooling water pump and its piping system are required, which complicates the structure and increases the size and weight of the entire internal combustion engine.

In addition, the secondary cooling water is hot water with a very high temperature because it is drained after cooling the silencer and cooling the primary cooling water. There is a risk of getting burned.

Further, the muffler is provided with an exhaust pipe for connecting the muffler and the cylinder, and a mounting flange portion for mounting the muffler on the cylinder block is formed at the tip of the exhaust pipe. Therefore, even if the silencer water jacket is formed around the silencer, the surroundings of the exhaust pipe cannot be cooled, and the outer peripheral portion of the exhaust pipe and the mounting flange portion become extremely hot. Therefore, there is a risk that a worker may get burned by touching the outer peripheral portion of the exhaust pipe or the mounting flange portion or may cause a fire due to overheating of the exhaust pipe or the mounting flange portion.

Means for Solving the Problem A cylinder is disposed in a cylinder block in a substantially horizontal direction, and a cylinder head is fixed to the top side of the cylinder block, and the cylinder block and the cylinder head are filled with primary cooling water. In an internal combustion engine having a jacket, a box body communicating with the water jacket and filled with primary cooling water is provided above the cylinder, and a heat exchanger through which secondary cooling water flows is provided above the box body. Then, a silencer connected to the cylinder is arranged below the cylinder, and a silencer water jacket is formed around the silencer, and the upper side and the lower side of the silencer water jacket are connected to the water jacket. Communicated with the bottom of the.

Further, an exhaust pipe connecting the muffler and the cylinder is provided in the muffler, a communication passage communicating with the upper side of the muffler water jacket is formed around the exhaust pipe, and the muffler is connected through this communication passage. The water jacket was communicated with the bottom of the water jacket.

Action The cylinder and the cylinder head are heated with the operation of the internal combustion engine, and the cylinder and the cylinder head are cooled by the primary cooling water in the water jacket. The primary cooling water that has cooled the cylinder and cylinder head rises inside the box,
After being cooled by the heat exchanger in the box, it descends into the water jacket and is used again for cooling the cylinder and cylinder head. Furthermore, part of the primary cooling water in the water jacket enters the muffler water jacket from the lower side of the muffler water jacket, and after cooling the muffler, rises from the upper side of the muffler water jacket into the water jacket. Further, it rises into the box body and is cooled by the heat exchanger.

Further, the muffler is provided with an exhaust pipe connecting the muffler and the cylinder, and a communication passage communicating with the upper side of the muffler water jacket is formed around the exhaust pipe, and the muffler water jacket is provided through this communication passage. The exhaust pipe is cooled by the primary cooling water by communicating with the bottom of the water jacket.

Embodiment An embodiment of the present invention will be described with reference to the drawings. Inside the cylinder block 2 of the internal combustion engine 1, the cylinder 3 is oriented substantially horizontally.
The cylinder block 2 is provided with a water jacket 4 located around the cylinder 3 and filled with primary cooling water. A cylinder head 5 is fastened and fixed to the top side of the cylinder block 2, and a water jacket 6 filled with primary cooling water is formed on the cylinder head 5. The water jacket 6 and the water jacket 4 are formed. And are communicated with each other through a communication port 7 formed on the lower side of the cylinder 3.

Next, the water jacket 6 is attached to the cylinder head 5.
Is integrally formed with the cylinder 3 and is filled with primary cooling water.
It extends further upward. A heat exchanger 10 in which a large number of thin tubes 9 are bundled at a predetermined interval is arranged in the upper part of the box body 8, and one end of the heat exchanger 10 is provided with an inlet for supplying secondary cooling water. A drain port 12 is formed at the other end of the heat exchanger 10 for discharging the secondary cooling water supplied from the water inlet port 11. In addition, these inlets
Both 11 and the drainage port 12 are projected to the outside of the box body 8,
A secondary cooling water pump 13 for supplying secondary cooling water into the thin tube 9 is connected to the water inlet 11, and the drain 12 is opened to the outside.

Further, a communication port 14 is formed at a position adjacent to the side of the heat exchanger 10 in the box body 8.
An oblique passage 15 is formed in the cylinder block 2 so as to connect the upper side of the water jacket 4 with the oblique passage 15. Further, inside the box body 8, there is provided a partition plate 17 for partitioning the inside of the box body 8 into a lower umbrella side of the heat exchanger 10 and a combustion chamber 16 side formed in the cylinder head 5. The partition plate 17 does not completely partition the inside of the box body 8, and the inside of the box body 8 is communicated with the upper end side and the lower end side of the partition plate 17. In addition, a water injection port 18 for injecting primary cooling water into the box body 8 and the water jackets 4 and 6 is formed in the upper portion of the box body 8, and a pressure regulating valve 19 is provided in the water injection port 18. A water inlet cap 20 incorporating is attached detachably. Further, a recess 21 is formed in the box body 8, and a spark plug 22 facing the combustion chamber 16 is disposed in the recess 21.

Next, the internal combustion engine 1 includes the cylinder block 2
A silencer 23, which is fastened to the outer wall surface of the cylinder 3, is arranged below the cylinder 3. The muffler 23 is provided with an exhaust pipe 24 that connects the muffler 23 and the machine cylinder 3, and further, the muffler 23 is fastened and fixed to the cylinder block 2 at the tip side of the exhaust pipe 24. Mounting flange
25 are formed. A silencer water jacket 26 is formed around the silencer 23, and an inlet 27 is formed on the lower side of the silencer water jacket 26.
A communication pipe 29 is connected between the above and a communication port 28 formed at the bottom of the water jacket 6. Further, the exhaust pipe 24
A communication passage 30 communicating with the upper side of the muffler water jacket 26 is formed around the circumference of the muffler water jacket 26, and the muffler water jacket 26 and the bottom portion of the water jacket 4 are communicated with each other through the communication passage 30. ing.

In such a structure, the primary cooling water is injected from the water injection port 18 to fill the water jackets 4 and 6, the silencer water jacket 26 and the box body 8 with the primary cooling water, and then the internal combustion engine 1 is started. When the internal combustion engine 1 is started, the cylinder 3, the cylinder head 5, and the silencer 23 are heated, and these are water jackets.
It is cooled by the primary cooling water in 4, 6 and the silencer water jacket 26.

The primary cooling water that has cooled the cylinder 3 and the cylinder head 5 becomes hot water and rises to the upper portion inside the box body 8 and is cooled by the heat exchanger 10. The primary cooling water cooled by the heat exchanger 10 and having a large specific gravity is partitioned by the partition plate 17 into the heat exchanger 10.
It goes through the lower part of the umbrella into the water jacket 6, cools the cylinder head 5 again, and enters the water jacket 4 from the communication port 7 to cool the cylinder 3. Further, part of the primary cooling water that has descended to the bottom of the water jacket 6 passes through the communication port 28 and the communication pipe 29, and the silencer water jacket
Enter the lower side of 26 and cool the silencer 23. The primary cooling water that has become hot water by cooling the silencer 23 rises from the upper side of the silencer water jacket 26 into the water jacket 4 through the communication passage 30 and further cools the cylinder 3. Ascends to the periphery of the heat exchanger 10 through the oblique passage 15 together with water. In addition, in the place where the primary cooling water in the silencer water jacket 26 rises in the communication port 30 and reaches the water jacket 4, the primary cooling water having a relatively low temperature is accumulated,
Since the primary cooling water rising rate from the silencer water jacket 26 is high, the primary cooling water does not flow from the inside of the water jacket 4 through the communication passage 30 into the silencer water jacket 26, and the primary cooling water is The convection circulation cools the cylinder 3, the cylinder head 5, and the muffler 23.

Here, since the difference between the silencer 23, which is one of the heat sources, and the heat exchanger 10 is large, the convection circulation of the primary cooling water is promoted, and the cylinders 3 and the like are sufficiently cooled to sufficiently cool the cylinders 3 and the like. Overheating is prevented and seizure and knocking due to overheating are reliably prevented. Further, since the silencer 23 is cooled using the primary cooling water, the temperature of the secondary cooling water discharged to the outside is higher than that of the conventional example in which the silencer 23 is cooled using the secondary cooling water. When the worker is exposed to the secondary cooling water that has been discharged to the outside, the risk of burns to the worker is reduced. Furthermore, since the exhaust pipe 24 and the mounting flange portion 25 are cooled by the primary cooling water in the silencer water jacket 26, the operator can cool the outer peripheral surface of the exhaust pipe 24 and the mounting flange portion 25.
The risk of getting burned when touching 25 is reduced, and a fire due to overheating of the exhaust pipe 24 is prevented.

Effect of the Invention In the present invention, a box body, which is connected to the water jacket formed in the cylinder block and the cylinder head as described above and is filled with primary cooling water, is provided above the cylinder, and the secondary cooling is provided in the upper part of the box body. A heat exchanger through which water flows is arranged, a muffler connected to the cylinder is arranged below the cylinder, and a muffler formed around the muffler has an upper side and a lower side of the water jacket. By connecting to the bottom part, the difference between the silencer, which is one of the heat sources, and the heat exchanger becomes large, so that convection circulation of the primary cooling water can be promoted, and therefore, the cooling of the cylinder etc. can be reliably performed. In addition, it is possible to reliably prevent seizure and knocking due to overheating of the cylinder and the like, and to cool the silencer externally compared to the case of using secondary cooling water. Since the temperature of the secondary cooling water that is drained to the cooler becomes low, the risk of burns when the drained secondary cooling water hits the operator can be reduced, and furthermore, the cylinder and silencer are By connecting the upper side of the muffler water jacket and the bottom part of the water jacket through the communication passage formed around the exhaust pipe to be connected, the exhaust pipe etc. can be cooled by the primary cooling water. This has the effects of reducing the risk of burns when touching a pipe or the like, and preventing the occurrence of fire due to overheating of the exhaust pipe or the like.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a vertical sectional front view, and FIG. 2 is a vertical sectional side view. 1 ... Internal combustion engine, 2 ... Cylinder block, 3 ... Cylinder, 4 ... Water jacket, 5 ... Cylinder head, 6
…… Water jacket, 8 …… Box, 10 …… Heat exchanger, 23…
… Silencer, 24 …… Exhaust pipe, 25 …… Communication passage, 26 …… Silencer Water jacket

Claims (2)

[Scope of utility model registration request] 1. A water jacket, in which a cylinder is arranged substantially horizontally in a cylinder block, a cylinder head is fixed to the top side of the cylinder block, and the cylinder block and the cylinder head are filled with primary cooling water. In the formed internal combustion engine, a box body that is in communication with the water jacket and is filled with primary cooling water is provided above the cylinder, and a heat exchanger through which secondary cooling water is caused to flow is provided above the box body, A muffler connected to the cylinder is disposed below the cylinder, and a muffler water jacket is formed around the muffler, and the muffler water jacket has an upper side and a lower side with a bottom part of the water jacket. A cooling device for an internal combustion engine, characterized in that the cooling device communicates with the. 2. An exhaust pipe connecting a muffler and a cylinder is provided in the muffler, and a communication passage communicating with the upper side of the muffler water jacket is formed around the exhaust pipe. 2. The cooling device for an internal combustion engine according to claim 1, wherein the silencer water jacket and the bottom portion of the water jacket are communicated with each other.