JPH0410326Y2 - - 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 cooling water to satisfy the required amount of heat dissipation due to the efficiency of the radiator and the heat capacity of the water. It was necessary to circulate the water, which caused a large drive loss in the water pump.

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 is a cooling system that uses 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. Yes (Tokkai Akira
56-32027, Published Patent Publication No. 1983-500140, etc.).

(Problem to be solved by the invention) However, in such a cooling device, the space above the refrigerant liquid level in the water jacket and inside the condenser is a gas phase space, and since air exists in the gas phase space, Even if the refrigerant vapor generated in the water jacket flows into the condenser, there is a problem in that the vapor cannot radiate heat and condense very well in the condenser due to the presence of air.

In addition, in cases where the refrigerant that has been condensed and liquefied in a condenser is circulated by a pump, a liquid level sensor, etc. is installed at the appropriate level of the water jacket, and the pump is driven and controlled according to this detection signal. The structure is complex and is prone to breakdowns and malfunctions.

The purpose of this invention is to solve these problems and provide an evaporative cooling device with excellent performance.

This invention also aims to improve maintainability, specifically to facilitate the injection of refrigerant into the cooling system during engine assembly.

(Means for Solving the Problems) In order to achieve the above object, this invention uses an engine water jacket that is mostly filled with liquid phase refrigerant and a condenser that maintains the interior in a gas phase.
In an evaporative cooling device for an internal combustion engine in which a vapor passage through which refrigerant vapor flows and a refrigerant passage through which liquefied refrigerant returns communicate to form a closed circuit in which the refrigerant circulates, the condenser is disposed above the water jacket, and the refrigerant passage is connected to the refrigerant passage. In addition to interposing a check valve in the middle of the refrigerant, an auxiliary tank storing a predetermined amount of liquid phase refrigerant is provided, and a first passage that opens into the liquid of this auxiliary tank and connects to the lower part of the condenser has a vapor pressure. Negative pressure response that opens a release valve that closes when the negative pressure exceeds a predetermined value into a gas phase portion in the auxiliary tank and opens a second passage connected to the steam passage when the negative pressure exceeds a predetermined value. a refrigerant injection passage which is provided with a valve and further communicates the lower part of the auxiliary tank with the water jacket;
An injection switching valve for opening and closing the refrigerant injection passage, and upper limit detection means having a liquid level sensor for detecting the upper limit of the liquid level in the water jacket are provided.

(Function) Therefore, when the refrigerant in the water jacket boils and steam begins to be generated, this steam flows into the upper condenser through the steam passage, but this steam causes the air in the system to Since the air is pushed toward the condenser and the release valve of the first passage is open at this time, the air in the system is discharged to the auxiliary tank via the first passage.

When the amount of steam generated increases and the pressure of the steam increases, the open valve closes and the gas phase space in the system becomes only steam, thus ensuring high heat dissipation and condensation in the condenser.

Further, since the refrigerant condensed and liquefied in the condenser returns to the water jacket by gravity via the refrigerant passage, a pump or the like is not required, simplifying the structure and eliminating the need for pump power or the like.

On the other hand, when the gas phase space in the system is only steam, the pressure in the system becomes negative as the temperature decreases when the engine is stopped, and in this case, the negative pressure responsive valve opens the second passage. Therefore, air is sucked into the system from the second passage, and negative pressure is prevented.

By the way, it goes without saying that in order for this evaporative cooling system to perform the above-mentioned functions without any trouble, the amount of refrigerant in the water jacket must not be too much or too little. Therefore, when assembling the engine, when refilling the refrigerant after it has been removed for maintenance reasons, or when replenishing refrigerant that has become insufficient as a result of long-term use, be sure to check the engine water tank. It is necessary to control the amount of refrigerant injected so that the bucket reaches a predetermined liquid level. On this point, in this invention, the auxiliary tank and water jacket are communicated via the refrigerant injection passage, so by opening the injection switching valve located in the middle of the refrigerant injection passage, water can be supplied from the auxiliary tank side. Refrigerant can be injected into the water jacket, and when the amount of refrigerant in the water jacket reaches a predetermined upper limit, the upper limit detection means that detects this with a liquid level sensor is activated and the refrigerant liquid level reaches the predetermined value. If the refrigerant injection is finished at that point, the refrigerant injection work for the water jacket will be completed. After the injection operation is completed in this way, the injection switching valve is closed again to form the original cooling system circuit, so that a predetermined cooling function can be performed from then on.

It is also possible to configure the engine so that the refrigerant is directly injected into the water jacket from the head cover, etc. on the top of the engine, but when an engine with such a configuration is installed in a cab truck, there is no way to replenish the refrigerant. The cab tailing must be performed each time, which deteriorates work efficiency. On the other hand, in this invention, the refrigerant is injected from an auxiliary tank that can be installed away from the engine, so this trouble can be solved depending on the location of the auxiliary tank. Furthermore, although the above explanation assumes that the injection switching valve is manually operated, the invention is not limited to this, and as described below as an example, the refrigerant is automatically injected in cooperation with the upper limit detection means. It is also possible to configure the passage to open and close.

(Embodiment) The figure shows an embodiment of the present invention, in which 1 is the engine (main body), 2 is a water jacket filled mostly with liquid phase refrigerant such as water, and 3 is the refrigerant from the water jacket 2. A cooling fan 4 supplies cooling air to the condenser 3, which cools and liquefies vapor.

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 with 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 therein is formed between the water trap 9 and the water jacket 2.

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 at a slightly higher position than the water jacket 2 in this case, and is opened into the liquid of this auxiliary tank 13 and connected to the lower part 7 of the condenser 3. A first passage 14 is formed, and a second passage 15 opens into the gas phase portion (near the liquid level in this case) in the auxiliary tank 13 and connects to the steam passage 5 above the water trap 9.

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

A negative pressure responsive valve 18 is installed 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. Incidentally, the auxiliary tank 13 is communicated with the outside air through an inlet 19 at the top which also serves as an air vent.

Further, pressure switches 20 and 21 are installed in the steam passage 5 near the water jacket 2 to conduct the refrigerant vapor depending on the pressure of the refrigerant vapor.

When the pressure of the steam reaches a set value, the pressure switch 20 operates a relay 22 provided between the power source and the cooling fan 4, thereby driving the cooling fan 4.
When the value becomes lower than the set value, the cooling fan 4 is stopped. Further, the pressure switch 21 opens the release valve 17 when the steam pressure is lower than a set value;
When the value exceeds the set value, a relay 23 provided between the power source and the open valve 17 is operated to close the open valve 17.

In addition, 24 is a liquid level sensor that detects the lower limit level of the refrigerant liquid level in the water jacket 2, and when the refrigerant liquid level drops to the level of the liquid level sensor 24, an alarm device 25 consisting of a buzzer etc. is activated. It's becoming like that.

Further, when the amount of evaporation increases abnormally, the relief valve 26 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.

Next, to explain the refrigerant injection route, which is another feature of this invention, 30 in the figure is the auxiliary tank 1.
3 and the water jacket 2, and there is an electromagnetic injection switching valve 31 in the middle of the refrigerant injection passage.
is interposed. Further, 32 is a second liquid level sensor attached facing the water jacket 2, which detects whether the refrigerant liquid level in the water jacket 2 has reached a predetermined upper limit value. 33 is a switching valve drive circuit that drives the electromagnetic injection switching valve 31 based on the output of the liquid level sensor 32; 34 is a switching valve drive circuit that notifies via this switching valve drive circuit 33 that the injection switching valve 31 has been driven; For example, it is an alarm device consisting of a monitor lamp or the like. Note that detailed effects of these will be described later.

Hereinafter, the effects based on the above configuration will be explained.

First, the function as a cooling device will be explained. When the engine is stopped, the inside of the cooling system is filled with a predetermined amount of refrigerant and air, and the open valve 17 of the first passage 14 is in an open state. Further, at this time, the injection switching valve 31 is closed, so that the refrigerant injection passage 30 is placed in a state where it does not affect the cooling effect.

Then, when the engine is started, 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, steam is generated while absorbing the 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. After this, when the amount of steam generated increases and the pressure of the steam increases to a certain extent,
The pressure switch 21 is turned on and the open valve 17 of the first passage 14 is closed.

Then, normal cooling operation begins in this state, but
In this case, when the amount of steam is not so large,
Heat is radiated and condensed from the steam in the condenser 3 using only the running wind. When the amount of steam increases and the steam pressure reaches a predetermined pressure, the pressure switch 20 is turned on and the cooling fan 4 is driven to perform forced cooling. Wind 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.

Further, the refrigerant condensed and liquefied in the condenser 3 falls by gravity from the lower part 7 of the condenser through the refrigerant passage 8, 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 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.

On the other hand, since the gas phase space in the system is only steam,
When the engine is stopped and the temperature in the system drops, the steam condenses and the pressure in the system drops significantly. At this time, the negative pressure responsive valve 18 in the second passage 15 is opened in response to this pressure drop. .

Therefore, air is sucked into the system from the second passage 15, and negative pressure is prevented. In addition, in this case, since the second passage 15 opens near the liquid level stored in the auxiliary tank 13, the refrigerant equivalent to the vapor discharged into the liquid in the auxiliary tank 13 as air is discharged when the engine is started is removed. By raising the liquid level of the auxiliary tank 13 by a corresponding amount above the opening of the second passage 15, the liquid is sucked into the system and recovered as air is sucked. Thereby, the refrigerant in the system is always maintained at an appropriate amount.

Next, to explain replenishment or injection of refrigerant, when it is necessary to fill the water jacket 2 with refrigerant, for example, immediately after engine assembly,
The operator first resets the drive circuit 33. As a result, the injection switching valve 31 is driven to open via the drive circuit 33, and the alarm device 34 is activated to notify the operator that the injection preparation state has been entered.

When the switching valve 31 is opened in this manner, the water jacket 2 and the auxiliary tank 13 communicate with each other via the injection passage 30. Therefore, with the relief valve 26 removed, the injection port 19 at the top of the auxiliary tank 13 is opened. By opening and pouring the liquid refrigerant, the injected refrigerant flows from the elevated auxiliary tank 13 into the passageway 30 and into the water jacket 2 under gravity. At this time, the air in the jacket 2 corresponding to the amount of injected refrigerant escapes from the mounting hole of the relief valve 26, so that the refrigerant smoothly flows into the jacket 2.

Water jacket 2 is removed by the above refrigerant injection work.
When the amount of refrigerant in the refrigerant reaches a predetermined upper limit, this is detected by the drive circuit 33 via the liquid level sensor 32, and the drive circuit 33 closes the switching valve 31 to open the injection passage 30. Upon closing, the operator is notified via the alarm device 34 that the injection of refrigerant into the water jacket 2 has been completed. Therefore, all that is left to do is to fill the auxiliary tank 13 with the required amount of liquid refrigerant, close the inlet 19, and attach the relief valve 26, and the work is completed.This allows the above-mentioned cooling function to be fully utilized. Become.

In addition, due to long-term driving, water jacket 2
If the amount of refrigerant in the refrigerant tank is insufficient, simply open the relief valve 26 and inlet 19 in a cold state during periodic inspection, reset the drive circuit 33, and remove the refrigerant from the auxiliary tank 13 in the same manner as above. The amount of refrigerant that is insufficient is automatically replenished into the water jacket 2, so in this case, the operator must fill the amount of refrigerant corresponding to the amount of the shortage into the auxiliary tank 1.
All you need to do is replenish it to 3. However, the above explanation is for the case where the auxiliary tank 13 is installed at a higher position than the water jacket 2, that is, the specified liquid level of the auxiliary tank 13 is higher than the water jacket 2.
auxiliary tank 13 so that the liquid level is the same as that of
If it is arranged at a relatively low position, it goes without saying that the injection of refrigerant into the auxiliary tank 13 will be completed at the same time when the liquid level in the water jacket 2 reaches a predetermined upper limit.

(Effects of the invention) As described above, according to this invention, since the gas phase space in the closed circuit is filled only with steam, high heat dissipation and condensation action can be obtained in the condenser, and the refrigerant can be pumped without using a pump or the like. Not only is circulation possible, but also excellent performance is ensured in that negative pressure in the closed circuit due to steam condensation is prevented when the engine is stopped.

Furthermore, with this invention, refrigerant can be easily injected into the water jacket from the auxiliary tank, so the workability of refrigerant injection is greatly improved.

[Brief explanation of the drawing]

The figure is a configuration diagram showing an embodiment of the present invention. 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...Release valve, 18...Negative pressure responsive valve, 30...
Refrigerant injection passage, 31... Injection switching valve, 32... Liquid level sensor, 33... Switching valve drive circuit, 34... Alarm device.

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 the evaporative cooling system for an internal combustion engine, the condenser is disposed above the water jacket, a check valve is interposed in the middle of the refrigerant passage, and an auxiliary tank storing a predetermined amount of liquid phase refrigerant is provided. A first passageway that opens into the liquid in the auxiliary tank and connects to the lower part of the condenser is provided with a release valve that closes when the vapor pressure exceeds a predetermined value and opens into the gas phase part of the auxiliary tank. A refrigerant injection passage connecting a lower part of the auxiliary tank and a water jacket, wherein a second passage connected to the steam passage is provided with a negative pressure responsive valve that opens when the negative pressure exceeds a predetermined value; an injection switching valve that opens and closes this refrigerant injection passage;
1. An evaporative cooling system for an internal combustion engine, comprising upper limit detection means having a liquid level sensor for detecting the upper limit of the liquid level in a water jacket.