JPS6183436A - Evaporative cooling device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To eliminate air bubbles inside a condenser tube without fail as well as to secure its radiating capacity in the best condition, by feeding a condenser lower part and a water jacket of an evaporative cooling device with a liquid phasic refrigerant simultaneously. CONSTITUTION:In an evaporative cooling device, a solenoid valve 17 is installed in position between a lower tank 14 at the lower part of a condenser 3 and a refrigerant feed pump 4, while a rotary valve 18 is installed in position between flow passages 16 and 26 of the pump 4. In time of starting this engine, a solenoid valve 28 is controlled to open while a solenoid valve 25 to close, and the solenoid valve 17 is controlled to be set to 'a flow passage B' while the rotary valve to 'flow passages a-b' respectively, whereby the pump 4 is turned to ON. With this constitution, a liquid phasic refrigerant inside a reservoir tank 21 is forcedly led into a water jacket 2 simultaneously via the flow passage 26, so that air left behind inside the system is forcedly discharged to the tank 21 outside the system via a passage 29 after being collected in an upper part of the system.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an internal combustion engine in which the internal combustion engine is cooled by circulating a specific liquid phase refrigerant from a condenser into a water jacket and boiling and vaporizing it within the water jacket. It relates to a boiling cooling device.

Conventional technology With the well-known water-cooled cooling system used in automobile engines, it is difficult to achieve highly accurate temperature control according to engine operating conditions, and the heat exchange efficiency in the radiator is difficult to achieve. It is also difficult to reduce the size and weight of the nine-piece device, which has its own limitations.

From this point of view, cooling devices that utilize the latent heat of boiling and vaporization of cooling water have been attracting attention in recent years (for example, the
7608, Japanese Patent Application Laid-open No. 57-62912, etc.), this basically boils and vaporizes liquid phase refrigerant (cooling water) in a water jacket, and then sends the generated vapor to an external condenser (radiator). After the heat dissipation and liquefaction,
The cooling water is circulated and supplied into the water jacket again, and unlike a simple temperature change, the cooling water is vaporized, which involves a phase change.
By utilizing heat, the required amount of heat dissipation can be satisfied with a very small amount of cooling water circulation, and the heat exchange efficiency in the condenser mentioned above is greatly improved compared to the conventional radiator, which improves the overall efficiency of the equipment. There is a possibility that a dramatic reduction in size and weight can be achieved. Moreover, it is possible to control the pressure inside the water jacket.
l Since the boiling point of the liquid phase refrigerant can be changed arbitrarily and quickly, the engine temperature can be adjusted according to the operating conditions from the viewpoint of thermal efficiency and anti-knock performance, for example, by controlling the drive of the cooling fan attached to the condenser. It also becomes possible to control the optimum temperature with good responsiveness and with high precision. In addition, in normal water-cooled cooling systems, a considerable temperature difference occurs between the water inlet and outlet of the water jacket, but in this cooling method that uses boiling of the refrigerant, boiling occurs in the high-temperature parts of the water jacket. It has also been pointed out that as a result of further acceleration, it is possible to achieve good cooling and a uniform temperature distribution.

However, even though this type of cooling device has various advantages, there are still many problems that need to be solved, and it has not been put into practical use. Specifically, the above-mentioned special public service
As described in Japanese Patent Laid-open No. 57608 and Japanese Patent Application Laid-open No. 57-62912, conventional rice cooling systems have a non-sealed structure in which a circulation system consisting of a water jacket, a condenser, etc. is partially communicated with the atmosphere. However, in non-sealed circulation systems such as zero, it is difficult to realize the boiling point control described above, and the vaporized refrigerant tends to flow out of the system. Moreover, if air, a non-condensable gas, exists in this system, it will accumulate in the condenser and significantly reduce heat dissipation performance, but in the non-sealed circulation system described above, air is completely removed from the system during operation. It's difficult to do.

In other words, in order to put this type of cooling device into practical use, it is necessary to form a closed circulation system mainly consisting of a water jacket and a condenser, and to perform a cycle of boiling and condensation of the refrigerant within the closed system, excluding air. It is necessary to In order to completely and easily remove air from the refrigerant circulation system under the above requirements, the applicant introduced a liquid phase refrigerant into the circulation system from a reservoir tank outside the system at the time of engine startup. Ideally, the system is once filled with water, and then excess refrigerant is discharged from the system to the reservoir tank by using generated vapor pressure while preventing air from entering, and a predetermined amount of refrigerant is sealed in the closed system. has proposed a boiling cooling device that realizes a typical operating state (Japanese Patent Application No. 145470/1984, etc.).

Problems to be Solved by the Invention The object of the invention is to further ensure the removal of air from the condenser in the above-mentioned boiling cooling device proposed earlier. That is, since the capacitor is mainly composed of fine tubes, air tends to adhere to the capacitor, and even if fM 7'j is obtained using a liquid phase refrigerant, the air that adheres to the capacitor is not easily released. When air accumulates in the condenser tube, the flow of steam is obstructed during operation, and that portion does not contribute to heat exchange, resulting in a significant reduction in heat dissipation capacity.

Friendly Means for Solving Problems This invention, in order to reliably remove the air adhering to the condenser as described above, removes a portion of the liquid phase refrigerant for air discharge from the reservoir tank outside the system. It is configured to be introduced from the bottom of the condenser, and includes an air exhaust passage connected to the top of the refrigerant circulation system, and a reservoir tank connected to the suction side of the refrigerant supply bonder via a flow path switching means. , a refrigerant introduction passage communicating with the discharge side of the refrigerant supply pump via a flow path switching means, and having a pair of branched tips connected to the lower part of the condenser and the water jacket, respectively.

action The air exhaust operation is performed, for example, when the engine is started.

In this system, the refrigerant supply pump is driven with the air discharge passage open, and the liquid phase refrigerant in the reservoir tank outside the system is forcibly introduced into the refrigerant circulation system to push out the air. The liquid phase refrigerant pumped by the bonder is simultaneously delivered to the lower part of the condenser and the water jacket via the branched refrigerant introduction passage. Therefore, the liquid phase refrigerant flows from the bottom to the top inside the condenser, and the air adhering to the inside of the condenser tube can be reliably removed and discharged. On the other hand, since the liquid-phase refrigerant is directly fed into the water jacket by the refrigerant supply pump, air bubbles attached to the wall surface can be similarly removed by the flow of the liquid-phase refrigerant. These airs are exhausted from the system through an air exhaust passage at the top of the system.

Embodiment FIG. 1 shows an embodiment of the evaporative cooling system according to the present invention, where l is an internal combustion engine equipped with a quarter jacket 2, 3 is a condenser for condensing a vapor phase refrigerant, and 4 is an electric type. The refrigerant supply pumps are shown respectively.

The water jacket 2 is formed over both the cylinder block 5 and the cylinder head 6 so as to surround the outer periphery of the cylinder and combustion chamber of the internal combustion engine 1, and the upper part, which is normally a gas phase space, is for each cylinder. They communicate with each other, and a steam volume lower is provided at an appropriate position above the two. This steam amount lower communicates with the upper inlet of the condenser 3 via a connecting pipe 8 and a steam passage 9. Note that 10 is a camp that closes the refrigerant inlet, and 11 is a diaphragm type negative pressure switch that detects whether or not the system internal pressure is negative pressure.

The condenser 3 includes an upper tank U having the above-mentioned inlet, a core section 13 mainly consisting of nine fine tubes along the vertical direction, and a lower tank 14 that temporarily stores the liquefied refrigerant condensed in the core section 13. For example, it is installed in a position such as the front of the vehicle that receives the wind from the vehicle.
Furthermore, an electric cooling fan 15 for forced cooling is provided on the front or back side. Further, the lower tank 14 is
It has a refrigerant outlet 14a at a relatively lower part thereof, and a refrigerant circulation passage 16 connected to the refrigerant outlet 14a.
It is connected to the refrigerant inlet 2 side of the water jacket 2 via the above.

A refrigerant supply pump 4 is interposed in the refrigerant circulation passage 16, and a third electromagnetic valve 17 and a rotary valve 18 are provided as flow path switching means on the suction side and the discharge side, respectively.
is provided.

Reference numeral 21 denotes an air-opened reservoir tank provided outside the refrigerant circulation system, from the bottom of which first to third auxiliary refrigerant passages 22, 23, and 24 are led out.

The first auxiliary refrigerant passage 22 is connected to a relatively lower portion of the lower tank 14 via a normally open second solenoid valve 25. Further, the second auxiliary refrigerant passage and the third auxiliary refrigerant passage are connected to the refrigerant circulation passage 16 via the above-mentioned third solenoid valve 17 and rotary valve 18, respectively. The above-mentioned 3' solenoid valve 17 is a three-way type solenoid valve, and when energized, it closes the second auxiliary refrigerant passageway and connects the refrigerant circulation passage 16 to cedar (flow path A), and when not energized, the refrigerant circulation passage is closed. 16 and communicates the second auxiliary refrigerant passage 23 with the refrigerant supply pump 4 (
Flow path B) is configured.

The refrigerant introduction passage 26 is connected to the refrigerant circulation passage 16 via the rotary valve 18, and has a pair of ends 26a, 261)K branched into the lower tank 14 and the water jacket 2, respectively. Connected to the bottom. In addition, in order to prevent backflow of refrigerant due to differences in liquid level, a reverse valve is interposed in the passage.

As shown in detail in FIG. 2, the rotary valve 18 connects the flow path on the discharge side of the refrigerant supply pump 4 to the water jacket 2 side (flow paths a-, -C) by rotating the cylindrical valve body 18a. ,
It can be selectively switched to either the third auxiliary refrigerant passage side (flow paths a-d) or the refrigerant introduction passage 26 side (flow path a%'b). For example, the step motor The rotational position of the valve body 18a is controlled by the following.

On the other hand, an air exhaust passage 29 having a normally closed first magnetic valve 28 is connected to the connecting pipe 8 which is the top of the refrigerant circulation system.
Its tip opens into the reservoir tongue 21.

Each of the above solenoid valves 28, 25, 17, rotary valve 18
, the refrigerant supply pump 4 and the cooling fan 15 are driven and controlled by a control device 31 using a so-called microcomputer system. Sensor 32. A second liquid level sensor blade is provided, and a temperature sensor blade is provided in the water jacket 2 at a position slightly below the first liquid level sensor 32 .

Next, FIGS. 3 to 3 are flowcharts showing the contents of the control executed by the control device [31], which will be explained below along the flow from starting to stopping the engine. In the figure, the first to third solenoid valves 28, 25, 17 are abbreviated as "Solenoid valve ■", "Solenoid valve ■", etc., respectively, and the liquid level f, ro inside the water jacket 2 is /H
It is abbreviated as "internal fluid level".

FIG. 3 is a flowchart showing an overview of the control. When the engine starts (ignition key 0N), the engine control starts, the initialization process in step 1 (see FIG. 5) is performed, and then the engine starts. It is determined whether it is an initial start or a restart, specifically whether the temperature detected by the temperature sensor 34 is higher than a predetermined temperature (for example, 45C) (step 2). If the initial startup is at a predetermined temperature or below, and the temperature is not yet warmed up, the process goes through air exhaust control in step 3 and then proceeds to warm-up control in step 4. After that, the control loop from step 5 to step 100 includes temperature control, liquid level control, etc. key 077
Repeat until the end. On the other hand, if the temperature is higher than the predetermined temperature in step 2, it is unlikely that air will enter over time when the engine is restarted, so air discharge side # (step 3) will be omitted.

Also, if a key OFF signal is input during the control,
The interrupt control routine shown in FIG. 4 is executed, and the key OF
After a certain process by the F control (step 11), the power is turned off and the series of controls ends.

FIG. 6 shows a flowchart of air exhaust control in step 3. Note that when the engine is started, the inside of the system is usually almost filled with liquid phase refrigerant (for example, a mixture of water and antifreeze), and the reservoir tank 21 is not filled with enough water to completely fill the system from this state. A sufficient amount of liquid phase refrigerant is stored. Air discharge control is to discharge air by completely filling the system with liquid phase refrigerant. First, in step 31, the solenoid valve 81 28f, l'-open" and the second solenoid valve 2
5t-"close", the third solenoid valve 17 t r flow path B", and the rotary valve 18 are controlled as "flow path a % b J", respectively, and the refrigerant supply pump 4 is turned on in step 32. As a result, the liquid phase refrigerant in the reservoir tank 21 is transferred to the refrigerant introduction passage 26.
The water is forcibly introduced into each of the lower tank 14 and the water jacket 2 at the same time. Therefore, the residual air remaining in the system is collected in the upper part of the system and is then forcibly discharged outside the system to the reservoir tank 21 side through the air discharge passage 29. As a result of the liquid phase refrigerant being fed into both the condenser 3 and the quarter jacket 2 from the bottom, the liquid phase refrigerant flows inside each from the bottom to the top, causing damage to the inside of the condenser tube and the water jacket. 2. Air bubbles attached to the inner wall surface can also be removed reliably.

The introduction of the liquid phase refrigerant is continued for a predetermined time at each step, specifically for a period of several seconds to several tens of seconds set in advance on a software timer, which is sufficient to fill the system with water. After the elapsed time, the refrigerant supply pump 4 is turned off (step 34), and the timer 2 is cleared (step 35) to warm up as shown in FIG.

Proceed to machine control (step 4).

When warm-up control begins, the inside of the condenser 3 is naturally filled with liquid phase refrigerant, so the heat dissipation capacity of the condenser 3 is suppressed to an extremely low level, and as a result, the refrigerant temperature inside the water jacket 2 decreases. It rises rapidly and eventually begins to boil. Warm-up control basically involves keeping the lower tank 14 and the reservoir tank 21 in communication via the first auxiliary refrigerant passage 22 until the refrigerant temperature in the water jacket 2 rises to the target temperature (step 41). ), and in step 43, the actual detected temperature is compared with the set temperature, and the detected temperature is "set temperature + 2.0℃".
(α3)'', the system is sealed (step 45) and this control is terminated.

The above set temperature (step 42) is optimally set at any time depending on the operating conditions such as engine load and rotational speed, and is set within a range of, for example, about 80 to 110 degrees Celsius (hereinafter referred to as step 51). 70. Similarly in step 8).

On the other hand, during this warm-up control, the inside of the system is open to atmospheric pressure, so if the set temperature exceeds approximately 100°C, the liquid phase refrigerant in the system will be pushed out to the reservoir tank 21 due to the generated vapor pressure. As a result, before the refrigerant temperature reaches the set temperature, the liquid level in the water jacket 2 and the lower tank 14
The liquid level in the tank drops excessively. To deal with this, when either the liquid level falls below the set level of the first liquid level sensor 32 or the second liquid level sensor (step 44
(N), the system is immediately sealed (step 45), and this control is terminated.

After the warm-up control is completed, the control loop from step 5 to step 10 is repeated as described above, but this control loop includes steps for finely controlling the temperature by turning on and off the cooling fan 15. The water jacket 2 is
The liquid level control in Step 6 (Fig. 9) to maintain the liquid level within the temperature range above the set level, and the step of expanding or reducing the effective heat dissipation area when the detected temperature deviates relatively largely from the target set temperature. 9 water level reduction control in the condenser (1st
0) and step 10, water level rise control in the capacitor (FIG. 11).

First, as mentioned above, the case where the detected temperature in the warm-up control (Fig. 7) is "set temperature + 2.0°C (α3)" and the control loop is entered will be explained. Step 52 in the diagram. Cooling fan 1 in step 53
5 is turned on, and since the upper limit temperature in step 7 has already exceeded [set temperature +2.0° C. (α3)], the water level reduction control in the capacitor shown in FIG. 10 is immediately started.

This water level reduction control in the condenser is performed by forcibly discharging the liquid phase refrigerant in the condenser 3 by the refrigerant supply pump 4 to the reservoir tank 21 outside the system via the rotary valve 18 in step 61. Step 62. Step 67) The liquid level inside the capacitor 3 is lowered to increase the heat dissipation ability. Refrigerant discharge continues until the detected temperature drops to "set temperature + 1.0°C (α5)" (steps 70, 71), and finally the system is sealed (step 72) to end. The end temperature is the upper limit temperature [set temperature + 2.0
°C (α3)] and lower limit temperature [set temperature -4.0 °C (α4)
] Within this range, and in consideration of responsiveness, set the temperature slightly higher than the set temperature. Furthermore, when the inside of the system is under positive pressure, it is possible to discharge the refrigerant by utilizing the pressure difference between the inside and outside of the system. (Step 6)
4, 65) L, the refrigerant is discharged via the first auxiliary refrigerant passage 22 in conjunction with the forced discharge by the refrigerant supply pump 4.

Even during the above-mentioned refrigerant discharge, the refrigerant continues to boil in the water jacket 2, so the liquid level gradually decreases, but if the liquid level on the water jacket side falls below the set level, the rotary Temporarily close the valve 18 [flow path a-c
Switch to J and connect capacitor 3 to water jacket 2
The liquid phase refrigerant is replenished to the first
The liquid level sensor 32 is maintained at the set level. In the event that the insufficient heat dissipation capacity cannot be avoided even if the liquid level in the capacitor 3 is lowered to the maximum, and the liquid level falls to the level set by the second liquid level sensor 33, This control is immediately terminated in order to prevent steam from flowing out (step 69). Also, for the same reason, capacitor 3 is
When the liquid level in the capacitor is below the level set by the second liquid level sensor 33, the control to lower the water level in the capacitor is not performed.

On the other hand, as mentioned above, the liquid level in the capacitor 3 is adjusted to ft.
I is controlled so that the engine heat generation amount and the heat radiation amount of the capacitor 3 are
After the system is almost in equilibrium below the boiling point and the system is sealed, the fan control (step 5) shown in FIG. 8 and the liquid level control (step 6) shown in FIG. 9 are repeated repeatedly. In the above fan control, the temperature inside the system can be controlled with even higher precision.
"Set temperature +0.5℃ (α1)" and "Set temperature -0.5℃
(α2)” (step 52), only the cooling fan 15 is controlled ON-OFF (step 53).
, 54), and in the liquid level control described above, when the liquid level in the water jacket 2 falls below the set V bell, liquid phase refrigerant is replenished from the condenser 3 side to the water jacket 2, and its Maintain the liquid level at the set level (steps 55-57).

In addition, if the system temperature falls below the lower limit temperature in step 7 [set temperature -4.0°C (α4)] due to disturbances such as an increase in vehicle running wind or changes in the set temperature itself due to changes in operating conditions, starts the water level increase control in the capacitor shown in FIG. This is a control in which the liquid phase refrigerant in the reservoir tank 21 is introduced into the condenser 3 side to raise the liquid level in the condenser 13, thereby suppressing the heat dissipation ability. In this case as well, forced introduction by the refrigerant supply pump 4 and introduction of the next refrigerant using the pressure difference inside and outside the system are used in combination. That is, when the inside of the system is under negative pressure according to the signal from the negative pressure switch 11 (step 81), the second solenoid valve 25 is opened (
In step 82), the refrigerant is introduced through the first auxiliary refrigerant passage 22. In addition, the forced introduction by the refrigerant supply pump 4 is performed once through the rotary valve 18 which is the "flow path a-CJ" with the third solenoid valve 17 set to the "flow path B" (step 82 and step 87). The refrigerant is introduced to the water jacket 2 side, and flows into the condenser 3 in the form of overflowing from the steam lower at the top of the water jacket 2.This refrigerant introduction is performed when the detected temperature is "set temperature - 3.0 °C (α6
)” (steps 84 and 85).
Finally, the system is sealed (step 86) and the process ends. The above-mentioned end temperature takes into account the responsiveness of temperature change to the rise in liquid level.

As a result of the water level increase control in the condenser described above, after the system temperature is guided to the upper limit temperature to the lower limit temperature in step 7, temperature control is performed only by the cooling fan 15 described above (steps 51 to 54).

Next, Figure 2 shows key OFF control (step 11) which is interrupted when the ignition key of the engine is turned OFF.

To do this, first set the set temperature to ℃ (step 9).
4) By doing this, the water level inside the condenser is controlled to be lowered as described above, and the heat dissipation capacity of the condenser 3 is utilized to the maximum, and the cooling fan 1 is turned off for about 10 seconds at most.
5 for forced cooling (steps 95, 96, step 53), the temperature inside the system becomes sufficiently low (e.g. 80°C) (step 93), or the inside of the system becomes under negative pressure (step 97). or after a certain period of time (for example, 1 minute) has elapsed (step 98), turn on the power.
(Step 99).

By turning off the power, the first solenoid valve 2, which is a normally closed solenoid valve,
8 is set to "closed", and the second solenoid valve 25, which is a normally open type solenoid valve, is set to "closed".
As the temperature in the system decreases, that is, the pressure decreases, liquid phase refrigerant is naturally introduced from the reservoir tank 21 through the first auxiliary refrigerant passage n, and eventually the entire system is filled with liquid phase refrigerant. The engine will be fully charged and ready for the next start. In addition, when introducing the liquid phase refrigerant mentioned above, the condenser 3
Since the air flows into the system through the air, even if a small amount of air enters for some reason during operation and adheres to the inside of the fine condenser tube, it can be reliably discharged to the upper part of the system.

On the other hand, the ignition key may be turned ON again during the above-mentioned key OFF control, but in this case, the process proceeds to step 100 based on the judgment in step 92, and the cooling fan is evacuated in advance. 1
5 and restore the set temperature, and step 95
, 98 software timer■.

Clear ■ (Step 101) L, key OF? It is progressing forward and returns to the ratio control state.

Effects of the Invention As is clear from the above explanation, the evaporative cooling device for an internal combustion engine according to the present invention, when discharging air by introducing the liquid refrigerant, simultaneously sends the liquid refrigerant to both the condenser and the water jacket. As a result, the liquid phase refrigerant flows inside each refrigerant, and air bubbles attached to the inside of the condenser tube or the inner wall surface of the water jacket can be reliably removed and discharged to the outside of the system. Therefore, the best heat dissipation ability of the capacitor can be ensured at all times, and the reliability and safety of this type of cooling device can be improved.

[Brief explanation of drawings]

Figure WI1 is a configuration explanatory diagram showing one embodiment of this invention;
The figures are new views of the rotary valve, Figures 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12. is a flowchart showing the details of control in this embodiment. 1... Internal combustion engine, 2... Water jacket, 3...
...Condenser, 4...Refrigerant supply bonder, 11...
Negative pressure switch, 14...Lower tank, 15...Cooling fan, 16...Refrigerant circulation passage, 17...Third solenoid valve, 18...Rotary valve, 21...Reservoir tank, ...Second solenoid valve, 26...Refrigerant introduction passage, 2
7...Check valve, 28...If magnetic valve, 29...
Air discharge passage, 31...control device, 32...first liquid level sensor, 33...second liquid level sensor, arm...temperature sensor. Outside 2 people Figure 3 Figure 4 Figure 5 Figure 7 Figure 8 Figure 9 Figure 11 Figure 12

Claims (1)

[Claims] (1) A sealed refrigerant circulation system consisting of a water jacket in which liquid phase refrigerant is stored, a condenser for vapor phase refrigerant condensation, and a refrigerant supply pump for liquid phase refrigerant circulation, and a system connected to the top of this refrigerant circulation system. , and an air discharge passage provided with an on-off valve, a reservoir tank connected to the suction side of the refrigerant supply pump via a flow path switching means, and communicating with the discharge side of the refrigerant supply pump via a flow path switching means. A boiling cooling device for an internal combustion engine, comprising: a refrigerant introduction passageway having a pair of branched end portions connected to a lower part of the condenser and the water jacket, respectively.