JPH02294515A - Separated cooler with pressurized type boiling preventing mechanism - Google Patents

Abstract

PURPOSE:To set a temperature low at the cylinder head side and high at the cylinder block side by dividing a water jacket into a forced convection part and a natural convection part provided with a pressurized type boiling preventing mechanism. CONSTITUTION:In the separated cooler 31A of an engine 1, a water jacket 24 is divided into a forced convection part 24a located above a communicating hole 22 provided in the upper peripheral outside of a cylinder liner 13 and a natural convection part 24b located below the communicating hole 22. The natural convection part 24b is provided with a pressurized type boiling preventing mechanism 30A for pressurizing internal cooling water 19 to prevent boiling. Thus, temperature at the cylinder head 3 side can be held relatively low by the forced convection part 24a. Also, temperature at the cylinder block 2 side which has a lot of slide parts and allows a lot of lubricating oil to circulate can be held relatively high by the natural convection part 24b.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a separation system in which the cylinder head side of an engine is cooled by forced convection cooling water, and the cylinder block side is cooled by natural convection cooling water. The present invention relates to a cooling device, and particularly to a separation cooling device equipped with a pressurized boiling prevention mechanism capable of raising the boiling point of cooling water in a natural convection section.

[Conventional Technology Generally speaking, water-cooled type engine cooling systems are the mainstream for engines installed in vehicles such as automobiles. There are some types as shown in FIG. 5 (a vertical sectional view of the engine) and FIG. 5 (a side view of the engine).

In Figures 4 and 5, reference numeral 1 is the engine, 2 is the cylinder block that constitutes the main body of the engine 1, and 3 is the engine 1.
4 is an oil pan provided at the lower end of the skirt portion 2a below the cylinder block 2, and a piston 12 is slidably inserted into the cylinder block 2. A cylinder liner 13 is formed, and the cylinder head 3 is installed so as to cover the upper end of this cylinder liner 13 via a gasket 2o. Further, numeral 5 is an intake pipe connected to the cylinder head 3, 6 is an exhaust pipe connected to the cylinder head 3,
7 is an intake passage provided inside the cylinder head 3 and the intake pipe 5; 8 is an exhaust passage provided inside the cylinder head 3 and the exhaust pipe 6; 9 is an intake valve provided in the intake passage 7; 10 is an intake passage provided inside the cylinder head 3 and the intake pipe 5; This is an exhaust valve provided in the exhaust passage 8.

The engine 1 is equipped with a water-cooled engine cooling system 11. This cooling device 11 includes a water jacket 14 provided in the cylinder block 2 and the cylinder head 3 so as to cover an internal cylinder liner 13 and valves 9 and 10, and a cooling water 19 stored in the water jacket 14. The radiator 15 to be cooled and the cooling water 19 are connected to each other so that the cooling water 19 flows through forced convection within the water jacket 14 (see the arrow in FIG. 5).
It consists of a water pump 16 that drives the. The water jacket 14 is connected to the radiator 15 through a cooling water supply pipe 17 and a cooling water discharge pipe 18, and the water pump 1G is connected between the cooling water supply pipe 17 and the water jacket 1l1. It is set up in In the cooling device 11 configured in this manner, the cooling water 19 that has been cooled by the radiator 15 is moved by the water pump 16 and flows into the water jacket 14 through the cooling water supply pipe 17, as shown in FIG. Convection flows inside as shown by the arrows, cooling the heat-generating parts around the cylinder liner 13 and valves 9 and 10, and is discharged into the radiator 15 through the cooling water discharge pipe 18, where it is cooled again by the radiator 15. be done. The engine is cooled by the circulating cooling water 19 in this manner.
[Problems to be Solved by the Invention] However, looking at the temperature distribution of the cooling water 19 in the water jacket 14 in the conventional engine cooling device described above, the temperature is high near the upper cylinder head 3, and the temperature is high in the vicinity of the upper cylinder head 3. The temperature becomes lower as the skirt portion 2a of the block 2 is approached. In other words, cylinder liner 1
The temperature distribution of the cylinder liner 13 is non-uniform depending on the temperature distribution of the cooling water 19, and such non-uniform temperature distribution of the cylinder liner 13 causes non-uniform deformation of the cylinder liner 13. This is undesirable because it causes increased lubricant consumption, uneven piston contact, and increased piston slap noise.

Further, excessive cooling of the side of the cylinder liner 13 near the skirt portion 2a causes the water pump 16 to work unnecessarily, resulting in deterioration of efficiency as a cooling device.

Furthermore, considering intake air filling efficiency, it is desirable to guide low-temperature, high-density intake air into the combustion chamber, and considering friction loss inside the engine, it is desirable to increase the lubricating oil temperature to improve its lubricity. It is recommended to leave the Therefore, in order to improve the intake air filling efficiency, the temperature on the cylinder head 3 side is lowered to lower the intake air temperature, while the temperature on the cylinder block 2 side is increased to maintain the temperature of the lubricating oil in the cylinder block 2. I want to do it like that.

Therefore. In order to make the temperature distribution of the cylinder liner uniform and to achieve more efficient cooling, the sixth
, an engine cooling device 21 configured as shown in FIG.
was proposed. Note that Figures 6 and 7 correspond to Figures 4 and 5, respectively, and in Figures 6 and 7, the same symbols as those in Figures 4 and 5 indicate similar parts. For this reason, the explanation of the parts of this example will be omitted.

In this engine cooling device 21, the water jacket 24 has a forced convection section 24a in which the internal cooling water 19 is pumped by the water pump 16, and a natural convection section 24b in which the internal cooling water 19 is not driven by the water bomb 16. It is divided into. In other words, the water jacket 24
As shown in the figure, the communication hole 22 is
a portion located above the communication hole 22 (forced convection portion) 2 4 a, and a portion located below the communication hole 22 (natural convection portion)
24b. Of these, the forced convection section 24
As shown in FIG. 7, the cooling water 19 inside a is driven by the water pump 16 and undergoes forced convection, but the natural convection section 24b is partitioned off from the water pump 16.
The cooling water 19 inside this natural convection section 24b is not circulated by the water pump 16 but undergoes natural convection. Due to this ellipse, the cooling water 19 that has been cooled by the radiator 15 is The water is struck by the pump 16, flows into the forced convection section 24a of the water jacket 24 through the cooling water supply pipe 17, and flows into the upper part of the cylinder liner 13 and the valve 9 while convecting as shown by the arrow in FIG. , 1o, and is discharged into the radiator 15 through the cooling water discharge pipe 18.
It is cooled again by the radiator 15. On the contrary,
In the natural convection section 24b of the water jacket 24, the cooling water 19, which has become high temperature by absorbing heat from the cylinder liner 13, rises near the upper communication hole 22 by natural convection and cools the forced convection section 24a side. The cylinder liner 13 is cooled by the water 19 and descends to cool the cylinder liner 13 again.

As a result, the movement of the cooling water 19 is reduced by the water jacket 2.
4 (that is, the forced convection section 24a), the total cross-sectional area of the circulation channel for the cooling water 19 is reduced, and even if the water pump 16 with the same output is used, the circulation speed of the cooling water 19 will be reduced. increases, and the forced convection heat transfer coefficient of the circulation system improves. The cooling capacity of the forced convection section 24a can be increased.

On the other hand, the natural convection section 24b is the forced convection section 24. It has a lower heat transfer coefficient than A, and the cooling water 19 inside it also tends to reach a high temperature.

Therefore, the temperature of the cooling water l9 in the water jacket 24 decreases in the vicinity of the upper cylinder head 3 compared to the conventional case, and increases in the lower part near the skirt portion 2a of the cylinder block 2.
The temperature distribution of the cooling water 19 around the area becomes nearly uniform. In other words, the temperature distribution of the cylinder liner 13 becomes uniform, and the deformation of the cylinder liner 13 also becomes uniform, which can be expected to prevent increased lubricating oil consumption, uneven piston contact, and increased piston slap noise. However, as mentioned above, simply water jacket 2
4 into the forced convection section 24a and the natural convection section 24b, the natural convection section 24 at the bottom of the cylinder block 2
If the temperature of the cooling water at point b is set high, the cooling water around the lower part of the cylinder block 2 will boil, and this portion will be filled with steam. If this happens, the heat transfer coefficient will drop sharply, and the temperature at the bottom of the cylinder block 2 will rise rapidly, potentially causing damage to the piston scuff, etc. For this reason, it is not possible to improve the intake air filling efficiency and reduce friction loss inside the engine as desired. The present invention was devised in view of these problems.
It is an object of the present invention to provide a separation cooling device with a pressurized boiling prevention mechanism, which allows the temperature on the cylinder head 3 side to be set low and the temperature on the cylinder block 2 side to be high.

[Means for Solving the Problems] Therefore, the pressurized boiling prevention machine side separation cooling device of the present invention has a water jacket provided on the outer side of the cylinder liner of the engine, and a cooling water inside the water jacket. In an engine cooling system that includes a water pump capable of forced convection and a radiator that cools the cooling water, the water jacket communicates with the cylinder liner through a communication hole provided at the upper part of the outer periphery of the cylinder liner. A forced convection part is located above the hole and causes internal cooling water to be forced into convection by being beaten by the water pump, and a forced convection part is located below the communication hole and causes internal cooling water to be driven by the water pump. The natural convection section is divided into a natural convection section where natural convection occurs, and is characterized by being equipped with a pressurized boiling prevention '44N that can pressurize the cooling water in the natural convection section and raise the boiling point of the cooling water. .

[Function] In the above-mentioned separation cooling device n with a pressurized boiling prevention mechanism of the present invention, the cooling water cooled in the radiator is driven by the water pump and enters the forced convection section of the water jacket, where the water is The cylinder liner is immediately moved by the bomb and forced convection occurs within the forced convection section to cool a required portion above the outer periphery of the cylinder liner, and then returns to the radiator, repeating the cycle. At this time, in the natural convection section of the water jacket, the internal cooling water is pressurized by the boiling prevention mechanism and its boiling point is raised, so even if the set temperature of the cooling water in the natural convection section is increased, the cooling water The water will no longer boil.

[Examples] Examples of the present invention will be described below with reference to the drawings.
FIG. 1 is a vertical sectional view of an engine showing a separation cooling device with a pressurized boiling prevention mechanism as a first embodiment of the present invention, and FIG. 2 is a separation cooling device with a pressurized boiling prevention mechanism as a second embodiment of the present invention. FIG. 3 is a side view of an engine showing a cooling device, and FIG. 3 is a side view of an engine showing a separate cooling device with a pressurized boiling prevention device as a third embodiment of the present invention. Note that in FIGS. 1 to 3, the same reference numerals as in FIGS. 4 and 5 and FIGS. 6 and 7 indicate substantially the same parts. In addition, the engine in each embodiment is an automobile engine. First, to explain the first embodiment, in FIG.
2 is a cylinder block forming the main body of the engine 1; 3 is a cylinder head forming the main body of the engine 1; 4 is an oil pan provided at the lower end of the skirt portion 2a below the cylinder block 2. and
A cylinder liner 13 into which the piston 12 is slidably inserted is formed inside the cylinder block 2.
The cylinder head 3 is installed so as to cover the upper end of the cylinder liner 13 via a gas pipe 1-20.

Further, reference numeral 5 indicates an intake pipe connected to the cylinder head 3;
6 is an exhaust pipe connected to the cylinder head 3; 7 is an intake passage provided inside the cylinder head 3 and the intake pipe 5; 8 is an exhaust passage provided inside the cylinder head 3 and the exhaust pipe 6; 9 is an intake valve provided in the intake passage 7, and 10 is an exhaust valve provided in the exhaust passage 8.

Such an engine 1 is equipped with a separate cooling device 31A with a pressurized boiling prevention mechanism. In addition, the first
Although the radiator 15, water pump 16, cooling water supply pipe 17, and cooling water discharge pipe 18 are not shown in the figure, these members are arranged almost in the same way as shown in FIG. This will be explained with partial reference to FIG.

As shown in FIG. 1, this separation cooling device 31A includes a water jacket 24 provided in the cylinder block 2 and the cylinder head 3 so as to cover the cylinder liner 13 and valves 9 and 10 inside, A radiator 15 (see FIG. 7) cools the cooling water 19 stored in the jacket 24, and a radiator 15 (see FIG. 7) that cools the cooling water 19 so that the cooling water 19 can undergo forced convection within the water jacket 14 (see the arrow in FIG. 7). The water pump 16 (see FIG. 7) drives the water pump 16 (see FIG. 7). The water jacket 24 is connected to the radiator 15 through a cooling water supply pipe 17 and a cooling water discharge pipe 18 so as to communicate with the radiator 15 (see FIG. 7).

As shown in FIG. 1, the water jacket 24 of this separation cooling device 31A is located above the communication hole 22 provided at the upper part of the outer periphery of the cylinder liner 13. Part (forced convection part) 24
a, and a portion (natural convection portion) 24b located below the communication hole 22. Of these, the cooling water 19 inside the forced convection section 24a located above is moved by the water bomb 16 and is connected for forced convection (see Fig. 7), but the cooling water 19 located inside the forced convection section 24a located below is Part 24
b is partitioned off from the water pump 16, and the cooling water L9 inside the natural convection section 24b flows to the water pump l6.
Natural convection occurs without being stirred by the air.

and. The natural convection section 24b is equipped with a pressurized boiling prevention mechanism 30Δ that pressurizes the internal cooling water 19 to prevent it from boiling.

This boiling prevention mechanism 30A includes a cooling water passage 33 interposed between the forced convection section 24a and the lower part of the natural convection section 24b.
and (5) a water pump 32 provided in the middle of the cooling water passage 33 to drive the cooling water in the forced convection section 24a into the natural convection section 24b, and a pressure sensor that detects the pressure of the cooling water in the natural convection section 24b. 35, a temperature sensor 36 that detects the temperature of the cooling water in the natural convection section 24b, and a natural convection section 2
The engine control unit (ECU) 34 controls the discharge amount of the pump 32 based on information from a pressure sensor 35 and a temperature sensor 36 so that the inside of the pump 4b has an appropriate pressure depending on the cooling water temperature. ．． Note that the appropriate pressure according to the cooling water temperature is the pressure that is applied to the extent that the cooling water does not boil, and is the pressure that increases as the cooling water temperature rises. When the temperature rises, the inside of the natural convection section 24b is pressurized to a high pressure so that the boiling point inside the natural convection section 24b becomes higher than the temperature of the cooling water.

Since the separation cooling device U31A with a pressurized boiling prevention mechanism as the first embodiment of the present invention is configured as described above, the cooling water 19 cooled in the radiator 15 is pumped by the water pump 16. It enters the forced convection section 24a of the water jacket 24 and generates forced convection using the recirculating force of the water pump 16, and the necessary parts such as the upper part of the outer periphery of the cylinder liner 13 and the heat-generating parts around the valves 9 and 10 above the cylinder liner 13 are heated. After cooling, the cooling water 19 returns to the radiator 15 and is cooled again.

While repeating such circulation, the engine is cooled by the cooling water 19, while the cylinder liner 13
In the main part excluding the upper part of the water jacket 24, that is, in the natural convection section 24b of the water jacket 24, the cooling water 19, which has become high temperature by absorbing heat from the cylinder liner 13, is moved near the upper communication hole 22 by natural convection. Forced convection section 2
The cylinder liner 13 is cooled by the cooling water 19 on the side 4a and descends to cool the cylinder liner 13 again.

The temperature of the cooling water 19 in the natural convection section 24b is detected by the temperature sensor 36 and sent to the ECU 34, so when the temperature of the cooling water 19 in the natural convection section 24b rises, the temperature inside the natural convection section 24b increases. The ECU 34 controls the discharge amount of the pump 32 based on the detection information of the pressure sensor 35 so that the pressure in the natural convection section 24b is increased to a predetermined pressure.

As a result, the cooling processing temperature in the radiator 15, the circulation speed of the cooling water in the forced convection part 24a, the flow path intermittent volume and length of the communication hole 22, etc. can be adjusted within the range in which the pressure in the natural convection part 24b can be adjusted. By adjusting the various conditions, it is possible to set the temperature in the forced convection part 24a to be kept low and the temperature in the natural convection part 24b to be kept high. For example, if the inside of the natural convection section 24b is pressurized to about 1.9 atmospheres, the boiling point can be reduced to 115
℃, and the temperature on the cylinder block 2 side can be set up to a corresponding high temperature range.

As a result, the cylinder head 3 side can be kept at a relatively low temperature by the forced convection section 24a, and low-temperature, high-density intake air can be guided into the combustion chamber, thereby increasing engine output by improving intake air filling efficiency. In addition, the cylinder block 2 side, which has many sliding parts and where a large amount of lubricating oil circulates, can be kept at a relatively high temperature by the natural convection section 24b, and by increasing the temperature of the lubrication well, its lubricity is improved, and the engine It is possible to achieve a reduction in friction loss.

In addition, the circulation of the cooling water 19 only needs to be carried out in a part of the water jacket 24 (strong convection part 1) 24a, and the total cross-sectional area of the cooling water circulation channel is reduced. Even if the pump 16 is used, the circulation speed of the cooling water increases, the forced convection heat transfer coefficient improves, and the cooling capacity in the forced convection section 24a can be increased.On the other hand, in order to obtain the cooling capacity, a smaller pump 1- 6 would be enough.

Furthermore, since the amount of coolant that must be forced into convection is reduced and the temperature of the coolant increases faster, warm-up of the coolant when starting the engine can be promoted, contributing to reduced fuel consumption, as well as the effect of speeding up the effectiveness of the heater.

Regarding the temperature distribution of the cooling water 19 in the water jacket 1-24, the temperature distribution near the upper cylinder head 3 is lower than before, and the temperature distribution in the lower part near the skirt portion 2a of the cylinder block 2 is excessively cooled. Since it becomes possible to adjust the temperature within a range that does not occur, the temperature distribution of the cooling water 19 can be made almost uniform, and the temperature distribution of the cylinder liner 13 can be made almost uniform, thereby preventing uneven deformation of the cylinder liner 13. This makes it possible to prevent an increase in lubricant consumption, uneven piston contact, and an increase in piston slap noise.

Now, to explain the second embodiment, as shown in FIG. 2, in the separation cooling device 31I3 of this embodiment, the configuration of the pressurized boiling prevention mechanism 30B is different from that of the first embodiment.

That is, in this pressurized boiling preventer 130B, the liquid level sensor 4 provided in the reservoir tank 37 of the radiator 15
1 is connected to the ECU 34, and this liquid level sensor 41
Based on the reservoir tank liquid level information input from
The ECU 34 is designed to control the operation of the pump 32. Note that a pipe 38 is led from the radiator cap 15a to the reservoir tank 37, and the radiator 15
The overflowing cooling water is introduced into the reservoir tank 37. Moreover, this reservoir tank 37 has a double bottom structure in which an upper bottom plate 40 with a communication hole is disposed at 1- of the bottom part 39 of the container. Ba,
The cooling water level in the reservoir tank 37 is set to be located below the upper bottom plate 40. This upper bottom plate 40 is. The cooling water 19 stirred below is prevented from flowing onto the upper bottom hole 40.

The liquid level sensor 41 is disposed above the upper bottom plate 40, and when the temperature of the cooling water 19 in the radiator 15 reaches a predetermined level or higher, it expands.
When the cooling water level in 7 rises, it is detected by the liquid level sensor 4.
1 is designed to be detected.

When the E C tJ 3 4 receives a detection signal from the liquid level sensor 41, the discharge amount of the pump 32 is increased so that the cooling water level in the reservoir tank 37 becomes below a predetermined level.

Except for these parts, the pressurized boiling prevention mechanism 30B of the second embodiment has the same oval shape as the pressurized boiling prevention mechanism 30A of the first embodiment, and other parts of the second embodiment are also the same. Since the structure is similar to that of the first embodiment, the explanation thereof will be omitted.

A separate cooling device 31B with a pressurized boiling prevention mechanism is a second embodiment of the present invention. Because of the above-mentioned structure, when the cooling water 19 boils in the natural convection section 24b at the bottom of the cylinder block 2, the apparent amount of circulating cooling water increases due to the evaporation of the cooling water, which increases the amount of water in the reservoir tank 37. It overflows.

When the cooling water level in the reservoir tank 37 passes through the upper bottom drawer 40 and reaches the liquid level sensor 41, the liquid level sensor 41 detects this, and this detection signal is sent to the ECU 34 to adjust the discharge amount of the pump 32. Appropriately increased.

As the cooling water is driven by this pump 32, the inside of the natural convection section 24b is pressurized and the boiling point of the cooling water 19 inside rises, so the cooling water 19 inside this natural convection section 24b stops boiling and generates The water vapor also liquefies. This prevents a decrease in heat transfer coefficient due to boiling of the cooling water, ensures a predetermined cooling capacity of the cooling water, and provides almost the same effect as the first embodiment. In addition, natural convection section 2
When the inside of 4b is pressurized, the apparent increase in circulating cooling water shells is also prevented, and the circulating cooling water does not overflow from the reservoir tank 37, and the cooling water level in the reservoir tank 37 is kept below the vicinity of the liquid level sensor 41. is maintained.

In addition, in this pressurized boiling prevention mechanism 30B, even if the cooling water 19 in the reservoir tank 37 is shaken when the vehicle turns or suddenly starts or stops, the coolant that has shaken below the upper bottom opening 40 is removed. Since the cooling water 19 does not flow onto the L portion bottom hole 40, the agitated cooling water will not splash onto the liquid sensor 41 and erroneously detect an increase in the liquid level.

Next, to explain the third embodiment, as shown in Fig. 3, in the separation cooling device fi31c of this embodiment, the configuration of the pressurized boiling prevention mechanism 30C is different from that of the first and second embodiments. , a pressure sensor 35 and a temperature sensor '3G similar to those of the first embodiment are connected to the ECU 34, and a liquid sensor 41 similar to that of the second embodiment is also connected.

Of these, the liquid level sensor 41 is for when the pressure sensor 35 and temperature sensor 36 fail, and in normal times, the liquid level sensor 41
As in the embodiment, the ECU 34 controls the discharge amount of the pump 32 based on the information from the pressure sensor 35 and the lagoon sensor 36, and when the pressure sensor 35 and the temperature sensor 36 fail, the ECU 34 controls the discharge amount based on the information from the liquid level sensor 41. The ECU 34 is configured to control the discharge mode of the pump 32.

Since the separate cooling device III31c with a pressurized boiling prevention mechanism as the third embodiment of the present invention has an oval structure as described above, it can obtain the same operation and effect as the first embodiment, and also has the pressure sensor 35. system or temperature sensor 36 system fails, the pump 32 is activated based on information from the liquid level sensor 41.
Since the discharge amount can be controlled, the reliability of the device is improved.

In each of the embodiments, the automobile engine 1 is equipped with the separation cooling devices 31A to 31C, but this device is not limited to automobile engines, and can be applied to engines for various other uses. It is.

[Effects of the Invention] As detailed above, according to the pressurized boiling prevention mechanism-equipped cooling device of the present invention, the water jacket provided around the outside of the cylinder liner of the engine and the cooling inside the water jacket are In an engine cooling system equipped with a water pump capable of forcing water to convect and a radiator that cools the cooling water, the water jacket connects to the cylinder liner through a communication hole provided at the upper part of the outer periphery of the cylinder liner. A forced convection part is located above the communication hole and uses the water pump to pump the internal cooling water for forced convection, and a forced convection part is located below the communication hole and uses the water pump to pump the internal cooling water. The system is divided into a natural convection section where natural convection occurs without being affected, and a pressurized boiling prevention machine is installed that can pressurize the cooling water in the natural convection section and raise the boiling point of the cooling water. In addition to increasing engine output by improving intake air filling efficiency, it is possible to reduce engine friction loss force by improving the lubricity of the lubricating oil, making it possible to significantly improve engine performance.

In addition, the cooling efficiency and cooling capacity of the engine can be improved, and on the other hand, the cooling water pump can be made smaller. Furthermore, in addition to the effect of promoting warm-up during startup, it also has the advantage of preventing increased lubricating oil consumption, uneven piston contact, and increased piston slap noise.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an engine showing a separate cooling device with a pressurized boiling prevention mechanism as a first embodiment of the present invention, and Fig. 2 is a longitudinal sectional view of an engine showing a separate cooling device with a pressurized boiling prevention mechanism as a second embodiment of the present invention. FIG. 3 is a side view of an engine showing a separation cooling device, and FIG. 3 is a side view of an engine showing a separation cooling device with a pressurized boiling prevention mechanism as a third embodiment of the present invention, and FIGS. 4 and 5 are side views of a conventional engine. Fig. 4 is a vertical sectional view of an engine equipped with this cooling system. Fig. 5 is a side view of the engine, and Figs. 6 and 7 show the engine cooling device proposed in the process of devising the present invention. Fig. 6 is a longitudinal cross-section of the engine equipped with this device. Figure 7 is a side view of the engine. 1-engine, 2-cylinder block. 2a...-Skirt portion of cylinder block 2,
3...-Cylinder head, 4--Oil pan, 5--Intake pipe, 6--Exhaust pipe. 7--Intake passage, 8-Exhaust passage, 9--Intake valve, 10-Exhaust valve, 12-Piston, 13--Cylinder liner, 15-Radiator,
15a -- Radiator cap, 16 -- Water pump, 17 - Cooling water supply pipe. IL-cooling water discharge pipe,
19-...Cooling water, 20-Gasket. 22 series of pipes,
24...Water jacket, 24a-forced convection section, 24b--natural convection section, 30A, 30B, 30C
- Pressurized boiling prevention mechanism, 31A, 31B, 31C - Pressurized boiling prevention machine with oval female cooling device, 32 - Water pump, 33 - Cooling water passage, 34. =1 engine control unit (ECU). 35-...Pressure sensor,
36-temperature sensor, 37-reservoir tank, 38-pipe, 39--container bottom, 40--top/bottom temporary, 41-liquid sensor.

Claims (1)

[Claims] An engine cooling system comprising a water jacket provided around the outside of a cylinder liner of an engine, a water pump capable of forcing cooling water in the water jacket to undergo forced convection, and a radiator that cools the cooling water. a forced convection section in which the jacket is located above the communication hole and is driven by the water pump to cause forced convection of internal cooling water through a communication hole provided at the upper part of the outer periphery of the cylinder liner; It is divided into a natural convection section located below the communication hole where the internal cooling water naturally convects without being driven by the water pump, and the cooling water in the natural convection section is pressurized to lower the boiling point of the cooling water. It is characterized by being equipped with a pressurized boiling prevention mechanism that can raise the
Separate cooling device with pressurized boiling prevention mechanism.