JPH0410332Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to an improvement of a boiling cooling device for an internal combustion engine that utilizes the latent heat of vaporization of a refrigerant.

(Prior Art) A water-cooled cooling system that circulates cooling water between an engine water jacket and a radiator is difficult to satisfy the required amount of heat radiation due to efficiency and dimensional limitations of the radiator and heat capacity of water. It is necessary to circulate a large amount of cooling water, which causes a large drive loss in the water pump, and it is difficult to variably control the cooling water to an appropriate temperature depending on engine operating conditions.

On the other hand, Japanese Patent Application Laid-Open No. 56-32027, Publication of Patent Publication No. 1983
No. 500140 and others propose a cooling device that uses the latent heat of vaporization of water to cool an engine with a small amount of circulating water. This system uses a cycle in which cooling water stored in a water jacket is boiled using the heat generated by the engine, and the generated steam is liquefied in a radiator and returned to the water jacket.

(Problem to be solved by the invention) By the way, in such a cooling system, the engine water jacket and the condenser (radiator) that cools and liquefies the refrigerant vapor generated in the water jacket are sealed. However, if the temperature inside the system becomes abnormally high for some reason during operation, the amount of steam increases and the capacity of the condenser cannot keep up.
There was a problem that the pressure within the system could become abnormally high.

(Means for solving the problem) In order to solve this problem, this invention
A closed circuit in which the engine water jacket, which is mostly filled with liquid-phase refrigerant, and the condenser, which maintains the interior in the vapor phase, are connected through a vapor passage through which refrigerant vapor flows and a refrigerant passage in which liquefied refrigerant is returned, and the refrigerant circulates. In an evaporative cooling system for an internal combustion engine, an auxiliary tank storing a predetermined amount of liquid-phase refrigerant is provided, and an auxiliary tank is opened into the liquid in the auxiliary tank to a portion above the water jacket liquid level of the closed circuit. The connecting passage is provided with a valve means that opens when the pressure in the closed circuit exceeds a predetermined value, and a cooling means is provided to promote heat dissipation from the auxiliary tank.

(Function) If the temperature or pressure within the cooling system becomes abnormally high for some reason during operation, the high pressure steam within the system is discharged into the liquid stored in the auxiliary tank via the valve means.

Therefore, abnormal conditions are avoided, and the steam is condensed and liquefied by the liquid stored in the auxiliary tank, and is prevented from being discharged to the outside.

By the way, the temperature of the liquid in the auxiliary tank increases due to the discharge of steam, but since the auxiliary tank is provided with a cooling means, the temperature of the liquid is always maintained at a low temperature, thus promoting condensation and liquefaction of the discharged steam.

(Embodiment) Fig. 1 shows an embodiment of the boiling cooling device according to this invention, in which 1 is an engine (main body), 2 is a water jacket filled mostly with liquid-phase refrigerant such as water, and 3 4 is a condenser that cools and liquefies the refrigerant vapor from water jacket 2, and 4 is a condenser 3.
This is a cooling fan that supplies cooling air to the

A water jacket 2 is formed from a cylinder block to a cylinder head so as to surround the cylinder and combustion chamber of the engine 1, and a condenser 3 is disposed above the water jacket 2.

The water jacket 2 communicates with the inlet (upper part) 6 of the condenser 3 via a steam passage 5 that opens into the gas phase space above the water jacket 2 so as to form a closed circuit for the condenser 3. An outlet portion (lower portion) 7 communicates with the liquid phase of the water jacket 2 via a refrigerant passage 8 .

A water trap 9 for gas-liquid separation is arranged in the middle of the steam passage 5, and a return passage 11 with a check valve 10 interposed between the water trap 9 and the water jacket 2 is formed.

A check valve 12 is interposed in the middle of the refrigerant passage 8 to prevent the liquid level of the refrigerant in the water jacket 2 from decreasing due to the pressure of the refrigerant vapor.

On the other hand, an auxiliary tank 13 storing a predetermined amount of liquid phase refrigerant is provided, and a large number of cooling fins 3 are provided on the outer periphery of the auxiliary tank 13.
0 is placed. A first passage 14 (discharge passage) that opens into the liquid in the auxiliary tank 13 and connects to the lower part 7 of the condenser 3;
A second passage 15 is formed which opens into the gas phase portion (near the liquid level in this case) inside and connects to the steam passage 5 above the water trap 9.

A check valve 16 and a solenoid valve 17 are interposed in the first passage 14, and the solenoid valve 17 opens and closes the first passage 14 as described later.

A negative pressure responsive valve 18 is interposed in the second passage 15 to open the second passage 15 in response to negative pressure when the pressure in the steam passage 5 is negative. Note that the auxiliary tank 13 is communicated with the outside air through an air vent 19 at the top.

A pressure sensor 20 and a temperature sensor 21 are installed in the steam passage 5 near the water jacket 2 to detect the pressure and temperature inside the water jacket 2, and these detection signals are sent to a control circuit 22 as a control means. .

Based on these detection signals, the control circuit 22 drives the cooling fan 4 when the pressure or temperature inside the water jacket 2 becomes higher than a set value,
It will stop when it falls below the set value.

Furthermore, based on these detection signals, the control circuit 22 opens the solenoid valve 17 of the first passage 14 during warm-up operation when the pressure and temperature inside the water jacket 2 are low, and when the pressure and temperature inside the water jacket 2 are extremely high and abnormally high. to control.

Note that 23 is a level sensor for detecting the lower limit level of the refrigerant liquid level in the water jacket 2, and when the refrigerant liquid level falls to the level of the level sensor 23, an alarm buzzer 24 etc. is activated.

Further, when the amount of evaporation increases abnormally, the relief valve 25 releases the steam to the outside to prevent the pressure from increasing in order to prevent damage to the inside of the steam system due to the pressure increase.

When the engine is stopped, the inside of the cooling system is filled with a predetermined amount of refrigerant and air, and when the engine is first started, the solenoid valve 17 of the first passage 14 is opened by the control circuit 22 during warm-up operation.

As the warm-up progresses, the temperature of the refrigerant in the water jacket 2 rises due to the heat generated by the engine, and when the refrigerant eventually begins to boil, it generates steam while absorbing latent heat of vaporization.

This steam flows from the water jacket 2 through the steam passage 5 to the upper condenser 3.
Accompanied by this steam, the air in the water jacket 2 and steam passage 5 is forced toward the condenser 3,
Furthermore, from the lower part 7 of the capacitor 3 a first passage 14
The water is discharged to the auxiliary tank 13 via the auxiliary tank 13.

At this time, some steam is also discharged along with the air, but since the first passage 14 opens into the stored liquid in the auxiliary tank 13, the steam is condensed by the stored liquid and remains in the tank 13, leaving only air. released into the atmosphere. Thereafter, the amount of steam generated increases, the pressure within the water jacket 2 increases to a certain extent, the temperature also increases, and when warm-up is completed, the solenoid valve 17 in the first passage 14 is closed.

Then, normal cooling operation begins in this state, but
In this case, when the pressure and temperature inside the water jacket 2 are not very high, heat is radiated and condensed from the steam in the condenser 3 only by the running wind, but the amount of steam increases and the pressure and temperature become lower than the set value. When the temperature rises, the control circuit 22 turns off the cooling fan 4.
is driven, and forced cooling air promotes heat dissipation and condensation of steam.

Therefore, the driving power of the cooling fan 4 is reduced, and the engine is cooled accurately and responsively.

On the other hand, the refrigerant condensed and liquefied in the condenser 3 falls by gravity through the refrigerant passage 8 from the lower part 7 of the condenser, and is returned to the water jacket 2 below through the check valve 12.

Therefore, it is possible to circulate the refrigerant without using a pump or the like, simplifying the structure of the device, and eliminating the need for pump power or control for refrigerant circulation.

In addition, at the beginning of cooling, the steam passage 5 is
The air in the system that is introduced into the condenser 3 through the steam is heavier than steam, so it stays in the lower part of the condenser 7, and most of it is discharged to the atmosphere side (auxiliary tank 13) through the first passage 14. However, at this time, the air that could not be completely discharged and the air remaining in the refrigerant passage 8 are cooled in the condenser 3 and introduced into the water jacket 2 through the refrigerant passage 8 together with the liquefied refrigerant. It is heated by the engine and is introduced into the condenser 3 through the steam passage 5 again together with the steam, and is then passed from the lower part of the condenser 7 to the first passage 1.
4 to the atmosphere. By repeating this cycle, the gas phase space in the system is almost filled only with steam, so that the condenser 3 dissipates heat only by steam, ensuring efficient heat dissipation and condensation.

By the way, if the temperature in the system becomes abnormally high for some reason during operation, the amount of steam may increase and the pressure in the system may also become abnormally high. 14 solenoid valves 17 are opened.

Therefore, since the steam in the system is discharged from the first passage 14 to the auxiliary tank 13, a rise in pressure is avoided, and as the steam is discharged, the heat of the system is released to the outside, so that the condenser The temperature is gradually lowered by the heat dissipation in step 3, and abnormally high temperatures are also avoided.

In this case, as the steam is discharged, the auxiliary tank 13
Although the temperature of the liquid in the auxiliary tank 13 increases, heat dissipation is promoted by the cooling fins 30 in the auxiliary tank 13, so the liquid temperature is always kept at a low temperature. Therefore, the vapor is not discharged to the outside as it is, and the refrigerant A reduction in volume is prevented.

Also, during operation, the gas phase space in the system is only steam, so when the engine is stopped and the temperature in the system drops, the steam condenses and the pressure in the system drops significantly. In response to the decrease, the negative pressure responsive valve 18 of the second passage 15 is opened.

Therefore, air is sucked into the system from the second passage 15, and negative pressure is prevented. In this case, since the second passage 15 opens near the liquid level stored in the auxiliary tank 13, the refrigerant and vapor equivalent to the vapor discharged into the liquid in the auxiliary tank 13 as air is discharged when the engine is started. The amount of refrigerant discharged during abnormally high temperature and high pressure is drawn into the system and recovered as air is taken in by raising the liquid level of the auxiliary tank 13 by that amount above the opening of the second passage 15.

FIGS. 2 and 3 show another embodiment that further improves the cooling performance of the auxiliary tank. In FIG. It is designed to be released to the outside.

Note that a large number of cooling fins 30 are arranged on the portion of the heat pipe 31 exposed to the outside of the tank so as to expand the heat dissipation area.

In FIG. 3, a dedicated cooling fan 32 is provided to correspond to the auxiliary tank 12, which has a large number of cooling fins 30 arranged around its outer periphery, in order to actively increase the amount of cooling air passing around the auxiliary tank 12. 33 is a switch circuit that is closed when the temperature of the liquid in the tank detected by the temperature sensor 34 is equal to or higher than a predetermined value.

(Effects of the invention) In summary, according to this invention, an auxiliary tank storing a predetermined liquid phase refrigerant is provided outside the cooling circuit, and steam etc. in the system is discharged into the liquid phase of the auxiliary tank as necessary. This makes it possible to take safety measures in times of abnormally high temperatures.

In addition, a cooling means is installed in the auxiliary tank to promote heat dissipation, which promotes condensation and liquefaction of discharged steam in the tank liquid, thus preventing steam from being released to the outside even at abnormally high temperatures. , the effect of preventing a decrease in the amount of refrigerant can be obtained.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing an embodiment of the present invention;
3 and 3 are main part configuration diagrams showing other embodiments, respectively. 2...Water jacket, 3...Condenser, 4...Cooling fan, 5...Steam passage, 8...
Refrigerant passage, 12... Check valve, 13... Auxiliary tank, 14... First passage, 15... Second passage,
17... Solenoid valve, 18... Negative pressure responsive valve, 20...
Pressure sensor, 21... Temperature sensor, 22... Control circuit.

Claims (1)

[Scope of utility model registration request] A closed circuit in which the engine water jacket, which is mostly filled with liquid-phase refrigerant, and the condenser, which maintains the interior in the vapor phase, are connected through a vapor passage through which refrigerant vapor flows and a refrigerant passage where liquefied refrigerant is returned, and the refrigerant circulates. In an evaporative cooling system for an internal combustion engine, an auxiliary tank storing a predetermined amount of liquid-phase refrigerant is provided, and the refrigerant is opened into the liquid in the auxiliary tank to a portion above the liquid level of the water jacket of the closed circuit. Boiling of an internal combustion engine, characterized in that a connecting passage is provided with a valve means that opens when the pressure in the closed circuit exceeds a predetermined value, and a cooling means is provided to promote heat dissipation from the auxiliary tank. Cooling system.