JPH0580564B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a boiling cooling device for an internal combustion engine that cools the engine by boiling and vaporizing a liquid phase refrigerant within a refrigerant jacket.

<Conventional technology> From the viewpoints of improving heat exchange efficiency using latent heat, improving fuel consumption rate by high temperature cooling, uniform temperature cooling of the combustion chamber wall, ease of control, and reduction in size and weight,
In recent years, cooling devices that utilize the latent heat of boiling and vaporization of cooling water have attracted attention, and for example, those described in Japanese Patent Publication No. 47-5019 and Japanese Patent Application Laid-Open No. 57-62912 are known. However, in the device described in Japanese Patent Publication No. 47-5019, a condenser is installed upright on the upper wall of the refrigerant jacket, and the generated vapor rising from the refrigerant jacket naturally flows into the condenser, and the condensed liquid phase refrigerant is The structure is such that the refrigerant drips directly into the refrigerant jacket, and there is a risk that the vapor flow rising from below the condenser may push out the droplets that have condensed inside the condenser. The amount of refrigerant held in the jacket and the amount of heat dissipated by the condenser are extremely unstable, making it completely unsuitable for applications such as automobile engines that require stable cooling.

Furthermore, the device described in Japanese Patent Application Laid-open No. 57-62912 is
The vapor generated in the refrigerant jacket is introduced into the condenser via the separation tank, and the liquefied refrigerant is once forced into the separation tank by a pump, so that the liquid level in the separation tank and the liquid level in the refrigerant jacket are naturally equal. Since the refrigerant is configured to replenish the refrigerant from the separation tank into the refrigerant jacket by taking advantage of the fact that There is a risk of cooling failure.

On the other hand, the present applicant forms a closed-loop refrigerant circulation system mainly consisting of a refrigerant jacket, a condenser, and a refrigerant supply pump, and also arranges a liquid level switch or a temperature switch at a predetermined level of the refrigerant jacket. After the refrigerant vapor generated in the refrigerant jacket is led to the condenser and condensed in its lower tank, the refrigerant is replenished into the refrigerant jacket by the operation of the refrigerant supply pump based on the detection of the above switch, and the refrigerant liquid level in the refrigerant jacket is increased. Various boiling cooling devices designed to maintain the temperature at a predetermined level have been proposed (for example, JP-A-60-36712, JP-A-60-36715, etc.).

However, all of these systems electronically control various electromagnetic valves and refrigerant supply pumps based on detection signals from liquid level switches or temperature switches, thereby providing a boiling cooling system control system that takes into account all engine operating conditions. Because it is a thing,
High reliability, durability, and safety are required, and from this point of view, it is difficult to simplify the device and reduce costs.

In addition, these devices employ a structure in which the liquid phase refrigerant condensed and stored in the lower tank below the condenser is guided to the engine's refrigerant jacket via a refrigerant supply pump, but the amount of liquid phase refrigerant in the lower tank, The liquid level affects the heat dissipation ability of the condenser, whereas the refrigerant supply pump operates according to the liquid refrigerant level or refrigerant temperature in the engine's refrigerant jacket, so the liquid refrigerant level in the lower tank fluctuates greatly. However, there is a risk that the amount of heat dissipated from the capacitor will change significantly. This change in the amount of heat dissipation causes the gas phase refrigerant (steam) pressure to fluctuate,
As a result, the boiling point of the liquid phase refrigerant in the refrigerant jacket fluctuates, and the engine temperature tends to become unstable.

Depending on vehicle driving conditions, for example, when turning, lateral G is applied to the liquid phase refrigerant in the lower tank, causing the liquid level to become uneven, or due to an abnormality in the cooling performance of the condenser, for example, when the engine is operated at high speed and under high load, or when there is insufficient running air. When the engine is idling, if the condensation and liquefaction capacity in the condenser decreases and gaseous refrigerant enters the lower tank and is released into the reservoir tank, the supply pump will suck in the gaseous refrigerant in the lower tank and temporarily The refrigerant supply tends to become unstable, as in the case where the supply of liquid phase refrigerant becomes impossible.

Therefore, with the aim of simplifying the former device, the present applicant proposed a new Japanese Patent Application No. 147813/1983. This will be explained with reference to FIG. 2, but even with this method, the latter problem cannot be eliminated, and other new problems have also occurred.

That is, in the boiling cooling device shown in FIG. 2, during normal operation after warm-up is completed, the refrigerant boils and vaporizes within the refrigerant jacket 1, and after cooling each part with the latent heat of vaporization at that time, it flows into the condenser 2 and condenses. and is stored in the lower tank 3. The refrigerant supply pump 4 continuously supplies liquid phase refrigerant from the lower tank 3 to the refrigerant jacket 1 based on the refrigerant temperature detected by a temperature switch 5 disposed in the refrigerant jacket 1.
The liquid phase refrigerant overflowing from the surplus refrigerant outlet 6 of the refrigerant jacket 1 passes through the overflow passage 7 and flows into the lower tank 3 due to the difference in height and slight pressure difference.
returned to nature. As a result, refrigerant jacket 1
The refrigerant liquid level inside the tank is always maintained at a predetermined level. The refrigerant in the reservoir tank 8 flows into the system as the pressure in the system decreases when the engine is stopped, and eventually the entire system is filled with liquid phase refrigerant. After the engine is started, boiling begins within the refrigerant jacket 1, and as a result, the pressure within the system increases, and the liquid phase refrigerant is naturally pushed out into the reservoir tank 8, securing the necessary vapor space in the upper part of the system. Here, since the refrigerant supply pump 4 is stopped until the predetermined warm-up completion temperature is reached, the refrigerant in the refrigerant jacket 1 is maintained in a stagnation state, and warm-up is proceeded quickly.

<Problems to be Solved by the Invention> However, according to the evaporative cooling device with a simplified control system and overall configuration as described above, the refrigerant supply pump 4 is activated when the refrigerant temperature in the refrigerant jacket 1 rises above a predetermined value. Since the condensed refrigerant in the lower tank 3 is pumped into the refrigerant jacket 1, the amount of refrigerant pumped is independent of the heat dissipation capacity of the condenser 2, that is, the refrigerant level in the lower tank 3. Therefore, the vehicle receives lateral G and the lower tank 3
If the liquid phase refrigerant in the lower tank becomes uneven or the condenser 2 has a heat dissipation abnormality and the gas phase refrigerant does not completely condense and liquefy in the condenser 2 and the gas phase refrigerant comes out into the reservoir tank 8, Since the amount of liquid phase refrigerant in 3 is small, it becomes impossible to supply liquid phase refrigerant to the engine within a short time. However, since an attempt was made to simplify the overall system by newly providing an overflow passage 7 to control the liquid level in the refrigerant jacket 1, the overflow flow of heated refrigerant from the refrigerant jacket 1 caused fluctuations in the refrigerant level in the lower tank 3. This results in further aggravating the above-mentioned inconvenience.
In addition, a new problem has arisen in that the refrigerant supply pump 4 is susceptible to cavitation due to high-temperature refrigerant.

In view of the above, the present invention always stabilizes the supply of liquid phase refrigerant to the engine so that even if problems such as poor condenser cooling or vehicle turning occur, the supply of liquid phase refrigerant to the engine does not become impossible immediately. The purpose is to

<Means for Solving the Problems> For this purpose, the evaporative cooling device for an internal combustion engine according to the present invention includes a refrigerant jacket that has a vapor outlet at the top and stores a liquid phase refrigerant up to a predetermined level, and a liquid level detection means for distinguishing and detecting liquid phase refrigerant and gas phase refrigerant, and a condenser from which the gas phase refrigerant generated from the refrigerant jacket is introduced into the upper part and the condensed liquid phase refrigerant is taken out from the lower part. a reservoir tank that is open to the atmosphere and temporarily stores the condensed liquid phase refrigerant; and the liquid level detection means is activated based on a signal indicating that the gas phase refrigerant is detected, and the liquid phase refrigerant in the reservoir tank is transferred to the refrigerant jacket. A refrigerant supply pump for pressure-feeding the refrigerant.

<Operation> According to the above configuration, during normal operation, the refrigerant in the refrigerant jacket absorbs heat from the combustion chamber wall and boils, and the latent heat of vaporization cools the combustion chamber wall with good heat exchange efficiency. The cooling effect is such that when there is a locally high temperature area, intense boiling occurs in this area, cooling is concentrated and uniform temperature distribution is achieved. Gas phase refrigerant (steam)
Since a large amount of latent heat is radiated and condensed in the condenser, heat exchange efficiency is high and the condenser can be made smaller. The condensed liquid phase refrigerant is not delivered directly, but after it is temporarily stored in a large capacity reservoir tank, the refrigerant is supplied to the refrigerant by operating a refrigerant supply pump to maintain the liquid phase refrigerant level in the refrigerant jacket at a constant level based on the output of a liquid level switch. Since the refrigerant is refluxed into the jacket, stable refrigerant supply is possible without the possibility that the refrigerant supply becomes defective depending on the driving condition of the vehicle or that the liquid phase refrigerant cannot be supplied immediately due to an abnormality in the cooling performance of the condenser.

The boiling temperature of the liquid refrigerant in the refrigerant jacket, that is, the vapor pressure, is determined by the atmospheric pressure applied to the reservoir tank, and the boiling temperature does not change when the liquid refrigerant supply pump operates, and the refrigerant boiling temperature is always stabilized at a substantially constant level. becomes possible.

<Example> An example of the present invention will be described below based on FIG. 1.

The internal combustion engine 11 includes a refrigerant jacket 12 in which refrigerant is stored, and a condenser 13 condenses the gas phase refrigerant sent from the refrigerant jacket 12 and stores the condensed liquid phase refrigerant in a lower tank 14 at the bottom. The liquid phase refrigerant in the lower tank 14 is once stored in the reservoir tank 15 and then returned to the refrigerant jacket 12 via the refrigerant supply pump 16. The refrigerant supply pump 16 is connected to the refrigerant jacket 1
Activation and deactivation are performed based on a detection signal from a liquid level switch 17, which is installed at a predetermined height position and serves as liquid level detection means for detecting gas phase refrigerant and liquid phase refrigerant separately. This is a schematic configuration of the present invention.

The refrigerant jacket 12 is formed over both the cylinder block 18 and the cylinder head 19 so as to surround the outer periphery of the cylinder and combustion chamber of the internal combustion engine 11, and the upper part, which is normally a gas phase space, is connected to each cylinder. They communicate with each other, and a steam outlet 21 is provided at an appropriate position in the upper part. The steam outlet 21 connects the connecting pipe 22 and the steam passage 2
3 to the upper inlet 13a of the condenser 13, and the connecting pipe 22 is formed with an air release passage 24 rising upward from the top of the refrigerant circulation system. Solenoid valve 2 on path 24
5 is interposed.

Further, at a predetermined level of the refrigerant jacket 12, specifically at a height position approximately in the middle above the combustion chamber on the cylinder head 19 side, the liquid level switch 17 is activated.
is installed. Note that 26 is a heater core for heating the vehicle compartment 28, which is connected to the refrigerant jacket 12 through a heater passage 27, and on the downstream side thereof, a heater pump 29 that operates in conjunction with a heater switch (not shown) is installed. It is provided.

The capacitor 13 includes a hot tank 31 having an upper inlet 13a, a core portion 32 mainly consisting of a fine tube along the vertical direction, and this core portion 32.
The lower tank 14 temporarily stores liquid-phase refrigerant condensed in the lower tank 14, and is installed in a position where it can receive wind from the vehicle, such as at the front of the vehicle. A cooling fan 33 is provided.

One end of the refrigerant circulation passage 34 is connected to a relatively upper portion of the lower tank 14, and the other end is connected to the reservoir tank 15 in communication.

The reservoir tank 15 is provided with a refrigerant supply cap 35 having air permeability on its upper wall and is freely attachable and detachable. The reservoir tank 15 is connected to the atmosphere opening passage 24 and the cap 35 with the solenoid valve 25 open.
Air enters the entire system from the refrigerant jacket 12 and supplies an amount of refrigerant such that the level of the liquid phase refrigerant becomes uniform and is located at the level at which the level switch 17 is located in the refrigerant jacket 12.

A refrigerant circulation passage 3 is provided at the bottom of the reservoir tank 15.
One end of the refrigerant 6 is connected to the refrigerant, and the other end is connected to a refrigerant inlet 12a provided on the cylinder block 18 side of the refrigerant jacket 12, and a refrigerant supply pump 16 is interposed in the intermediate portion. The refrigerant flow rate of the refrigerant supply pump 16 is set to a level that slightly exceeds the maximum required refrigerant circulation amount, taking into consideration the maximum amount of steam generated at high speed and high load and the amount of refrigerant taken out from the refrigerant jacket 12 in the form of droplets. ing.

The solenoid valve 25 is of a normally closed type, and is opened and closed in conjunction with an ignition switch (not shown). be exposed. Temperature switch 41
is set to, for example, 45° C., and is turned on below the set temperature, opening the solenoid valve 25. Further, when the ignition switch is turned off, the solenoid valve 25 is closed because it is a normally closed type. The cooling fan 33 is turned on and off based on a temperature switch 42 provided in the lower tank 3. When the temperature switch 42 detects that the temperature is higher than the set value, the cooling fan 33 is rotated to increase the heat dissipation effect of the condenser 2.

In order to prevent the liquid phase refrigerant carried out with the vapor flow from flowing into the condenser 2, a refrigerant jacket 12 is provided at the vapor outlet 21 to collect the liquid phase refrigerant.
The structure includes a liquid phase refrigerant recovery passage 43 connected to the refrigerant.

Next, the operation of the evaporative cooling device configured as described above will be explained.

First, when the engine is stopped, the solenoid valve 25 is closed.
When the engine is started (ignition switch is turned on), the temperature inside the refrigerant jacket 12 reaches 45°C.
In the following cases, the temperature switch 41 is turned on and the solenoid valve 25 is opened. Therefore, in the circulation system, there is an atmosphere opening passage 24 and a cap 35 of the reservoir tank 15.
Atmospheric air is introduced through the reservoir tank 15,
The liquid level in the condenser 13 and the refrigerant jacket 12 is kept the same, and the liquid phase refrigerant (eg, ethylene glycol aqueous solution) is in equilibrium.

The refrigerant in the refrigerant jacket 12 absorbs heat and rises in temperature as the engine operates. At this time, refrigerant jacket 1
Since there is no excess refrigerant in the chamber 2, that is, the heat receiving capacity is small and the refrigerant merely remains, it is possible to warm up in a short time. The same goes for when the heater is used in low outside temperature conditions.In extremely low temperatures, no heat is added to the excess refrigerant, and the wall portion of the refrigerant jacket 12 in contact with the liquid phase refrigerant is small, so the amount of heat radiated from the outer wall is small and the heater performance is improved. You can improve your performance. Also, the amount of refrigerant initially put in is small, solenoid valve 25
When the valve opens and the equilibrium position becomes lower than the liquid level switch 17 in the refrigerant jacket 12, the refrigerant supply pump 16 operates to replenish the refrigerant, so that the combustion wall can be reliably cooled.

As warming progresses, the liquid phase refrigerant in the refrigerant jacket 12
When the temperature exceeds the set temperature of 45℃, solenoid valve 2
5 closes the atmosphere opening path 24. Therefore, the refrigerant circulation system becomes a closed loop refrigerant circulation system that is opened to the atmosphere only through the cap 35 of the reservoir tank 15.
As the refrigerant temperature increases further, the refrigerant jacket 12
The refrigerant inside the system will eventually start to boil, and a gaseous refrigerant region will gradually form in the upper part of the refrigerant jacket 12 and the upper part of the condenser 13, and as the internal pressure increases due to boiling, the liquid refrigerant will circulate from within the system. It is gradually pushed out into the reservoir tank 15 through the passage 36.

By the way, air, which is a non-condensable gas, introduced into the upper part of the refrigerant circulation system when the engine is started, is pushed by the gas phase refrigerant and guided to the condenser 13 after the refrigerant boils. This reduces the heat dissipation ability of the capacitor 13, but
The air is further pushed down and forced out into the reservoir tank 15 through the refrigerant circulation passage 34. In other words, the air is naturally exhausted. Note that some gas phase refrigerant flows out into the reservoir tank 15 along with the air, but this is condensed and recovered within the tank 15.

In this way, as the gas phase refrigerant area expands above the condenser 13, the heat dissipation capacity of the condenser 13 increases. When a large amount of vapor is generated, the liquid level of the refrigerant in the refrigerant jacket 12 decreases, and the output of the liquid level switch 17 that detects this causes the refrigerant supply pump 16 to operate, supplying liquid phase refrigerant into the refrigerant jacket 12. The temperature of the liquid phase refrigerant in the refrigerant jacket 12 does not rise and is maintained at a substantially constant value).
Thereafter, the liquid level in the condenser 13 naturally moves up and down in response to an increase in heat generation due to changes in engine load, vehicle running wind, airflow from the cooling fan 33, etc., while keeping the system temperature approximately constant. cooling fan 33
When the temperature of the refrigerant in the lower tank 14 increases, the operation is started by a detection signal from the temperature switch 42, and the condenser 13 is forcibly cooled. Lower tank 14
The temperature of the refrigerant in the condenser 13 is determined by the degree of use of the condenser 13 (the proportion of the gas phase refrigerant in the condenser core 32).
The temperature of the refrigerant in the lower tank 14 becomes high when the vehicle is running on a slope, where there is little wind and the engine generates a large amount of heat, or when the vehicle is idling, where there is no wind. Here, the operating temperature of the temperature switch 42 of the lower tank 14 is set to the temperature at which the degree of use of the condenser 13 is maximized (the temperature of the liquid phase refrigerant of the lower tank 14 at the time of maximum use is near the temperature of the gas phase refrigerant) 90
The cooling fan 33 is operated at a temperature of about 100°C to 100°C.
Therefore, the cooling fan 33 does not operate most of the time when the engine is operating, and operates only when necessary, thereby reducing electrical load and reducing noise. In addition, the refrigerant supply pump 16 supplies the reservoir tank 15 according to the detection signal of the liquid level switch 17.
A liquid phase refrigerant is supplied from the refrigerant jacket 12 to the refrigerant jacket 12, and the refrigerant liquid level in the refrigerant jacket 12 is always maintained at a predetermined level.

Here, in the present invention, the refrigerant in the reservoir tank 15 is supplied to the refrigerant jacket 12 instead of the refrigerant in the lower tank 14 as described above. The amount of refrigerant in the reservoir tank 15 is the lower tank 1.
Since it is configured to have a sufficiently large number compared to 4,
Taking out the refrigerant from the reservoir tank 15 does not affect the amount of liquid refrigerant in the lower tank 14, that is, the refrigerant liquid level. As a result, even if the vehicle turns and receives lateral G and the liquid phase refrigerant level in the lower tank 14 is tilted,
Alternatively, if the condensation and liquefaction capacity in the condenser 13 decreases due to a cooling abnormality in the condenser 13 during engine high-speed, high-load operation or engine idling operation with insufficient running air, the gas phase refrigerant may enter the lower tank 14. is simply discharged into the reservoir tank 15, and the liquid phase refrigerant is stably supplied from the reservoir tank 15 into the refrigerant jacket 12.

Also, the engine stops (ignition switch off)
After that, the solenoid valve 25 is closed, and as the steam pressure decreases due to the decrease in the heat radiation temperature in the system, the reservoir tank 1
The liquid phase refrigerant moves into the system from 5, and eventually the system becomes full of water. This prevents the air introduced during startup from being exhausted and corroding the inner surface of the capacitor 13. At this stage, the liquid phase refrigerant temperature is 45
When performing a hot restart at temperatures above ℃, there is no need for rapid warm-up, so the solenoid valve 25 remains closed, but when the liquid phase refrigerant temperature is below 45 ℃ when cold, the solenoid valve 25 is closed. Open the valve and introduce air into the system again to perform rapid warm-up.

As mentioned above, in this embodiment, air is actively introduced into the system, so the reservoir tank 1
The amount of refrigerant in the tank 5 can be reduced, and the reservoir tank 15 can be downsized.

Furthermore, since the refrigerant is taken out from the reservoir tank 15 to supply the refrigerant to the refrigerant jacket 12, even if the lower tank 14 of the condenser 13 is substantially omitted, the liquid phase inside the condenser 13 is Does not adversely affect refrigerant level control. Therefore, the capacitor 13 can be made extremely small.

<Effects of the Invention> As is clear from the above explanation, the boiling cooling device for an internal combustion engine according to the present invention can effectively cool refrigerant even with an extremely simple configuration using a complicated control circuit, a large number of solenoid valves, etc. It is possible to achieve cooling with excellent cooling efficiency and temperature uniformity using a boiling/condensing cycle.

Furthermore, since the refrigerant is supplied to the refrigerant jacket from the reservoir tank, the refrigerant jacket can always be replenished with liquid phase refrigerant, which is most important for cooling the engine, in a stable manner. Furthermore, since only the minimum amount of liquid phase refrigerant required for cooling is stored in the refrigerant jacket when the engine is started, rapid warm-up is possible, and air can be naturally discharged without any special action. It has excellent reliability and safety. Furthermore, since the cooling fan can be operated while making full use of the capacitor, there is less dependence on the cooling fan, making it possible to save power and reduce noise.

[Brief explanation of the drawing]

FIG. 1 is a schematic structural explanatory diagram showing one embodiment of the present invention, and FIG. 2 is a schematic structural explanatory diagram of a conventional example. 11... Internal combustion engine, 12... Refrigerant jacket, 13
...Condenser, 15...Reservoir tank, 16...Refrigerant supply pump, 17...Liquid level switch, 23...Steam passage, 34, 36...Refrigerant circulation passage.

Claims (1)

[Scope of Claims] 1. A refrigerant jacket having a vapor outlet at the top and storing a liquid phase refrigerant up to a predetermined level, and a refrigerant jacket provided at an appropriate level position within the refrigerant jacket to carry the liquid phase refrigerant and the gas phase refrigerant. A liquid level detecting means for detecting the liquid level separately; a condenser into which the gaseous refrigerant generated from the refrigerant jacket is introduced into the upper part and the condensed liquid refrigerant is taken out from the lower part; and an air-opened reservoir which temporarily stores the condensed liquid refrigerant. An internal combustion engine characterized by comprising: a tank; and a refrigerant supply pump that is activated based on a signal from which the liquid level detection means detects a gaseous refrigerant and pumps the liquid refrigerant in the reservoir tank to the refrigerant jacket. Engine boiling cooling system.