JPH0326252Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to 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 requires a large amount of water to satisfy the required amount of heat dissipation due to efficiency and dimensional limitations of the radiator and the heat capacity of water. It is necessary to circulate the 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 the engine operating conditions.

Therefore, a cooling device has been proposed that uses the latent heat of vaporization of the cooling water to cool the engine with a small amount of circulating water. This system performs cooling using a cycle in which the cooling water (liquid phase refrigerant) stored in the water jacket is boiled using the heat generated by the engine, and the generated steam is condensed and liquefied in a radiator (condenser) and returned to the water jacket. (Utility Model Application No. 18714, Patent Application No. 58-145467, etc.).

(Problem to be solved by the invention) By the way, in such a cooling system, a liquid level sensor is installed as a means of detecting the refrigerant liquid level in the water jacket, and the water jacket is detected by evaporation during cooling operation. When the refrigerant liquid level in the bucket drops below the sensor level, the supply pump is activated to send liquefied refrigerant from the condenser side, but with this method, the supply pump is driven and stopped frequently. There were cases where the intermittent sound was easily heard as noise.

Also, when the supply pump is stopped, the supply of refrigerant does not stop immediately due to the force of the refrigerant flow, which causes the liquid level in the water jacket to rise above the sensor level and maintain it at an appropriate level. There was a problem that the cooling condition was adversely affected.

(Means for solving the problem) This idea connects the engine water jacket, which is mostly filled with liquid-phase refrigerant, and the condenser, which maintains the interior in the vapor phase, to the vapor passage through which the refrigerant vapor flows in the upper part, and the condenser. In the boiling cooling system, an internal combustion engine is equipped with a cooling fan that communicates with a refrigerant passage through which liquefied refrigerant is returned via a supply pump to form a closed circuit in which the refrigerant circulates, and supplies forced cooling air to a condenser. A mechanically driven pump that is constantly driven based on engine rotational force is provided as a supply pump, and a relief passage connecting the water jacket to the lower tank of the condenser, a float that follows the liquid level of the water jacket, and a float that is linked to the float. and a valve means having a valve that opens the relief passage when the liquid level rises above a predetermined value.

(Function) Therefore, the supply pump is constantly driven, and the relief passage is opened when the refrigerant liquid level in the water jacket is at a predetermined level due to the operation of the valve means that follows the liquid level in the water jacket. Therefore, the surplus of the refrigerant sent to the water jacket by the drive of the supply pump is accurately returned to the lower tank of the condenser through the escape passage. This eliminates the intermittent sound of the pump, which is a source of noise, and at the same time keeps the refrigerant liquid level in the water jacket at an appropriate level.

(Example) Figure 1 shows an example of the boiling cooling device according to this invention. First, the basic structure will be explained.
1 is the engine (main body), 2 is a water jacket filled mostly with liquid phase refrigerant such as water, 3 is a condenser that cools and liquefies the refrigerant vapor from the water jacket 2, and 4 is the liquefied refrigerant from the condenser 3. a lower tank for storing refrigerant, 5 a supply pump for returning the stored refrigerant in the lower tank 4 to the water jacket 2;
A cooling fan 6 supplies forced cooling air to the condenser 3.

The water jacket 2 is attached to the cylinder block 1 so as to surround the cylinders and combustion chambers of the engine 1.
a and cylinder head 1b, and a predetermined amount of liquid phase refrigerant is sealed inside.
The upper part of the water jacket 2 is a gas phase space filled with refrigerant vapor, and in a multi-cylinder engine, the gas phase space is communicated with each other between cylinder sections.

The water jacket 2 communicates with the condenser inlet via a steam passage 7 facing the gas phase space and connected thereto.

The lower tank 4 of the condenser 3 communicates with the water jacket 2 via a refrigerant passage 8, forming a closed circuit in which refrigerant circulates between the water jacket 2 and the condenser 3.

In the case of an automobile, the condenser 3 is installed in a position where the wind flows through the vehicle, and the cooling fan 6 is positioned on the front or back side of the vehicle to supply forced cooling air to the condenser 3. The supply pump 5 is located in the middle of the refrigerant passage 8 and pumps the liquid phase refrigerant accumulated in the lower tank 4 to the water jacket 2 (described later).

10 is a control circuit, and water jacket 2
A control system is formed with a means for detecting the refrigerant liquid level in the engine (described later), a temperature sensor 12 provided in the steam passage 7, and other means for detecting the engine operating state (not shown).

The temperature sensor 12 detects the engine temperature from the temperature or pressure of the refrigerant, and provides an output corresponding to the engine temperature to the control circuit 10 as an actual temperature signal.

The control circuit 10 detects the actual temperature detected by the temperature sensor 12 as well as engine rotation, fuel supply amount, etc. through well-known sensors, determines the operating state of the engine, and determines the operating state of the engine based on the comparison with the actual temperature. The operation or stop of the cooling fan 6 is controlled so that the engine temperature reaches a predetermined temperature depending on the operating state at that time.

It goes without saying that the relationship between the engine operating state and the control temperature value can be set freely depending on the engine specifications, purpose, and application, but in general, automobile engines are operated at low loads or rotational speeds, such as when driving around town. Maintains a relatively high temperature in the operating range,
The temperature should be lowered in the high-speed, high-load range.

To explain the basic function of the cooling system based on the above configuration, when the liquid phase refrigerant in the water jacket 2 is heated by the engine combustion heat, it reaches a boiling point according to the pressure in the system at that time. When the temperature reaches that point, it starts boiling, takes away the latent heat of vaporization, and evaporates.

At this time, the refrigerant boils more actively in the higher temperature parts of the engine 1 and cools the part corresponding to the latent heat of vaporization, so that the combustion chamber and the cylinder wall are kept at a substantially uniform temperature. This makes it possible to raise the temperature of the entire combustion chamber to near the limit temperature that does not cause problems such as abnormal combustion.

The refrigerant vapor generated as a result of the boiling cooling action flows from the gas phase space of the water jacket 2 to the condenser 3 via the vapor passage 7, is cooled by heat exchange with the outside air in the condenser 3, is condensed and liquefied, and is gradually liquefied. It is stored in the lower tank 4.

In this case, the inside of the condenser 3 is in a gas phase, and the high-temperature refrigerant vapor is cooled by the outside air with a large temperature difference under good heat transfer conditions with the metal surfaces that make up the condenser 3. As a result, the heat dissipation efficiency is significantly increased compared to when heat is dissipated in the liquid phase.

The refrigerant liquefied in the condenser 3 and stored in the lower tank 4 is returned to the water jacket 2 by the supply pump 5, and boiling cooling is continued by repeating the above steps.

The latent heat of vaporization of the refrigerant is extremely large, and the condenser 3 provides high heat dissipation and condensation, so the engine can be efficiently cooled with a small amount of refrigerant, and the cooling temperature can be controlled in a responsive manner according to the operating conditions. It becomes possible to do so.

In such a boiling cooling device, a relief passage 13 connecting the water jacket 2 and the lower tank 4 is formed.

This escape passage 13 is provided separately from the refrigerant passage 8, and the following valve means is interposed in the middle thereof.

That is, as valve means, a float 17 that is displaced up and down depending on the refrigerant liquid level, and a valve 18 that is displaced together with the float 17 to open and close the escape passage 13 are provided.

The relief passage 13 is opened at a position where the refrigerant liquid level in the water jacket 2 is at an appropriate level, and at the same level, the relief passage 13 is branched to form a float chamber 19 in which the float 17 is housed. Ru.

A valve 18 is attached to the lower part of the float 17 via a rod 20 that penetrates the bottom of the float chamber 19 in a watertight manner. When it opens, the escape passage 13 is closed when it is lower than that.

A mechanically driven pump is provided as the supply pump 5, and although not shown, this pump 5 is connected to the engine crankshaft and is constantly driven based on its rotational force.

Note that 15 is a gas-liquid separator that separates liquid droplets etc. from the refrigerant vapor passing through the steam passage 7, and
It is now possible to switch back to water jacket 2.

That is, during cooling operation, refrigerant vapor that boils and evaporates in the water jacket 2 flows into the condenser 3 from the vapor passage 7, where it is cooled and liquefied, and then falls into the lower tank 4. The liquefied refrigerant is returned to the water jacket 2 by a continuously operated supply pump 5.

At this time, when the refrigerant liquid level in the water jacket 2 falls below a predetermined level, the valve 18 closes the relief passage 13 due to the lowering of the float 17, and the refrigerant evaporates. The refrigerant liquid level does not drop excessively.

On the other hand, by constantly driving the supply pump 5,
The amount of refrigerant in the water jacket 2 increases, but when the refrigerant liquid level is above a predetermined level, the valve 18 is opened by the float 17 and the relief passage 1 is opened.
3 is kept open. Therefore, the surplus of the refrigerant sent by the supply pump 5 is released into the relief passage 1.
The refrigerant liquid level in the water jacket 2 does not rise above a predetermined level.

In this way, the refrigerant liquid level in the water jacket 2 can always be maintained at an appropriate level, and as a result, the intermittent sound of the pump, which is a source of noise, can be eliminated, and the refrigerant level in the water jacket 2 can be maintained at an appropriate level. Stable boiling and evaporation effects are maintained and good cooling conditions can be obtained.

Note that, since the amount of refrigerant circulated is small, the loss caused by constant operation of the supply pump 5 is small. (Effects of the invention) As described above, according to the invention, while a mechanically driven pump that is constantly driven as a supply pump is provided,
Since a valve means is provided to open and close the relief passage depending on the refrigerant liquid level in the water jacket, noise caused by intermittent operation of the supply pump is eliminated, and the refrigerant liquid level in the jacket is always maintained at the appropriate level. level and can maintain a good cooling condition.

In addition, in the present invention, the refrigerant liquid level in the water jacket is controlled by a simple structure consisting of a float that follows the refrigerant liquid level and a valve that is linked to this float, thereby reducing the cost of the cooling device. It also has the effect of being achievable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention. 2...Water jacket, 3...Condenser, 4...Lower tank, 5...Supply pump, 6...
...Cooling fan, 7...Steam passage, 8...Refrigerant passage, 10...Control circuit, 12...Temperature sensor, 1
3...Escape passage, 17...Float, 18...Valve.

Claims (1)

[Scope of utility model registration request] 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 to a vapor passage through which the refrigerant vapor flows in the upper part, and a refrigerant passage, which returns the liquefied refrigerant from the condenser via a supply pump. to form a closed circuit in which refrigerant circulates,
In a boiling cooling system for an internal combustion engine that is provided with a cooling fan that supplies forced cooling air to a condenser, a mechanically driven pump that is constantly driven based on engine rotational force is provided as the supply pump, and a water jacket is connected to the lower tank of the condenser. a relief passage connected to the water jacket, a float that follows the liquid level of the water jacket, and a valve that operates in conjunction with the float and opens the relief passage when the liquid level rises above a predetermined value. A boiling cooling device for an internal combustion engine characterized by: