JPS6183415A - Evaporative cooling apparatus of internal-combustion engine for car - Google Patents

Abstract

PURPOSE:To prevent the excessive rise of the temperature of the air blown-out from a heater by forming a bypass passage onto a heater core and controlling the bypass flow-rate by coolant, in a heating apparatus for introducing the coolant supplied from a cooling jacket into a heater core. CONSTITUTION:The heater core 17 of a heating apparatus is connected between the coolant taking-out port 19 and the coolant return port 22 of a cooling jacket 2, and a bypass passage 23 is connected in parallel to the heater core 17. A heating pump 18 is installed between a bypass passage 23 and the heater core 17. A control valve 24 is controlled according to the coolant temperature detected by a temperature sensor 35, and the bypass flow-rate is controlled so that the temperature of the coolant supplied into the heater core 17 becomes nearly constant. Therefore, the over-heating in the case when an engine is in high-load state can be prevented, and always comfortable temperature in car interior can be secured.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention cools the engine by boiling and vaporizing the liquid phase refrigerant that is circulated and supplied from the condenser into the water jacket in the water jacket of the engine. The present invention relates to an evaporative cooling system for an internal combustion engine for an automobile, a part of which is used for heating the interior of a vehicle.

<Prior art> In the well-known water-cooled cooling system used in internal combustion engines for automobiles, a considerable temperature difference occurs between the water inlet and the water outlet of the water jacket, making it difficult to achieve uniform cooling. It is difficult to achieve this, and there is a natural limit to the heat exchange efficiency of the radiator, so the radiator and cooling fan have to be large. Moreover, since a large amount of cooling water is required in the cooling system, it takes time to complete warm-up at a cold start, and temperature control according to the engine operating state cannot be performed with good responsiveness.

Generally, this type of cooling system is equipped with a heater core for heating the vehicle interior, and is configured to heat the air blown by the proa by flowing high-temperature cooling water from the engine. With type heaters, as mentioned above, it takes time for the cooling water to warm up sufficiently, so the heating performance is slow to rise at startup, and heating performance decreases on long downhill slopes. There is.

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.
Japanese Patent No. 2912 proposes a boiling cooling device that cools an engine by boiling and vaporizing cooling water, and uses the generated steam as a heat source for a heater.

This involves boiling and vaporizing the liquid phase refrigerant (cooling water) stored in the water jacket, guiding the resulting vapor through a separation tank to a condenser, liquefying heat, and then pumping it into the separation tank using an electric pump. The liquid level in the water jacket is maintained at a predetermined level by natural circulation between the separation tank and the water jacket due to its own weight, and a portion of the generated steam is sent to the heater core before reaching the condenser. The system is bypassed to heat the vehicle interior. Compared to a water-cooled type that uses a simple temperature change of the cooling water, this cooling device that uses phase change can satisfy the required amount of heat radiation by circulating a much smaller amount of cooling water, and the heat exchange efficiency in the condenser can be improved. This is a significant improvement over a water-cooled radiator, and is also advantageous in terms of uniform temperature distribution in each part of the engine.

<Problems to be solved by the invention> However, by adopting such a boiling cooling device, the warm-up characteristics are improved and the temperature of the refrigerant supplied to the heater core becomes higher, so that the heater blowout temperature during normal operation becomes better. However, during high-load operation or when water is used as a refrigerant,
When used with about 0% antifreeze mixed in, there was a problem that the heater core population temperature became high and the blowing temperature became too high.

Therefore, the present invention makes it possible to obtain good heating performance during normal operation by using the high-temperature refrigerant of the evaporative cooling device, and also prevents an excessive rise in the heater outlet temperature due to an excessive rise in the heater core inlet temperature. The purpose is to provide comfortable heating performance.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a water jacket for an engine having a steam outlet at the top, and a water jacket for an engine that is connected to the steam outlet and temporarily stores liquefied refrigerant at the bottom. A boiling cooling device for an internal combustion engine for an automobile, comprising a condenser having a refrigerant tank, and a refrigerant supply pump provided between the refrigerant tank and the walk jacket,
A heater core for heating the passenger compartment is connected to the refrigerant outlet from the water jacket, and a heater pump is provided between the heater core and the refrigerant return port to the water jacket. A communication path that communicates with the heater core inlet and a control valve that controls the flow rate of the refrigerant flowing through the communication path according to the temperature of the refrigerant are provided.

In this way, the refrigerant is normally circulated in this order from the refrigerant outlet from the engine's water jacket to the heater core, the pump, and the refrigerant return port to the water jacket, and the refrigerant (vapor) that has become high temperature in the water jacket is transferred to the heater core. (including)
is supplied to obtain a sufficient heating effect, while when the heater core inlet temperature rises excessively, a control valve opens a communication path connecting the pump outlet and the heater core inlet.
By supplying low-temperature refrigerant from the pump outlet to the heater core, a rise in the heater core inlet temperature is suppressed and an excessive rise in the heater blowout temperature is prevented.

<Embodiment> Fig. 1 shows an embodiment of the evaporative cooling device according to the present invention, in which 1 is an internal combustion engine equipped with a water jacket 2, and 3 is an engine for condensing a gas phase refrigerant. and 4 indicate an electric refrigerant supply pump, respectively.

The walk jacket 2 is arranged in a cylinder block 5 so as to surround the outer circumference of the cylinder and combustion chamber of the internal combustion engine 1.
The upper part, which is normally a gas phase space, communicates with each other in each cylinder, and a steam outlet lower is provided at an appropriate position in the upper part. The lower Fuji air outlet 1 is connected to an upper tank 11 (described later) of the condenser 3 via a connecting pipe 8 and a steam passage 9, and the connecting pipe 8 has a discharge pipe attached thereto, which is the top of the refrigerant circulation system. The portion 8a is formed in an upwardly raised shape, and a cap 10 seals the upper end opening.

The condenser 3 includes an upper tank 11 to which the vapor passage 9 is connected, a core section 12 mainly consisting of fine vertical tubes, and a refrigerant tank that temporarily stores the liquefied refrigerant condensed in the core section 12. It is constructed of a lower tank 13, and is installed at a position such as the front of the vehicle to receive wind from the vehicle running, and is further provided with an electric cooling fan 14 for forced cooling on the front or back side thereof. Further, the lower tank 13 has one end connected to a refrigerant circulation passage 15 at a relatively lower portion thereof, and one end of a second auxiliary refrigerant passage 30 described later is connected to an upper portion thereof. The other end of the refrigerant circulation passage 15 is connected to a refrigerant port 16 on the cylinder head 6 side of the water jacket 2, and a second solenoid valve 31, which will be described later, is provided in the middle part.
and the refrigerant supply pump 4 are interposed.

A refrigerant circulation system is configured by the above water jacket 2 - condenser 3 → lower tank 13 - second solenoid valve 31 - refrigerant supply pump 4 - water jacket 2,
During normal operation, a refrigerant made of water with some additives, for example, circulates in this circulation system while repeatedly boiling and condensing.

Further, a heater core 17 and an electric heater pump 18 are further attached to the circulation system, and constitute a part of the refrigerant path. That is, like the condenser 3, the tacho core 17 is mainly composed of a plurality of fine tubes extending in the vertical direction, and the upper inlet 17a is a refrigerant outlet provided on the cylinder head 6 side of the water jacket 2. 1
9 through a heater refrigerant introduction passage 20, and a lower outlet 17b is connected to a port 18a of the pump 18. The outlet 18b of the pump 18 is connected by a refrigerant return passage 21 to a refrigerant return port 22 provided at the lower portion of the water jacket 2 on the cylinder block 5 side.

Here, the downstream side of the pump 8 of the refrigerant return passage 21 and the refrigerant four-person passage 20 are connected by a communication passage 23, and a control valve 24 is interposed at the connection portion between the refrigerant four-person passage 20 and the communication passage 23.

The control valve 24 operates according to the temperature of the refrigerant, and when the temperature is low, it shuts off the communication passage 23 and maintains the refrigerant introduction passage 20 in a communicating state (solid arrow), and when it is high temperature, it shuts off the refrigerant introduction passage 20. The connecting path 23 and the heater core population 17a are communicated with each other (dashed line arrow).

Specifically, as shown in FIGS. 2 and 3, a case 102 is disposed inside a cylindrical body 100 having a connection port 101 for the communication path 23 on the side wall, and a flange portion 103 of the case 102 is slidable. It has become. Then, wax 1 is placed between the case 102 and the elastic sleeve 104 provided at the center thereof
05 is enclosed, and the piston 1 is enclosed within the elastic sleeve 104.
One end of 06 is inserted. And piston 106
The other end is fixed to the inner wall of the main body 100 via a support 107. A guide tube 108 is fixed to the flange portion 103 surrounding the case 102, and a spring 109 placed outside the guide tube 108 and acting on the flange portion 103 causes the case 102 to move away from the valve seat 110. is biased to the right. A flow passage 111 is formed in a portion of the flange portion 103 between the outer wall of the case 102 and the guide tube 108.

The heater core 17 is used by being incorporated into an air conditioner as shown in FIG. 4, for example. That is, 41 is an evaporator for cooling, 42 is a blower, 43 is a damper for switching between inside and outside air that selectively switches between the inside air intake 44 and the outside air intake 45, and 46 is an air mix damper that adjusts the amount of heated air. 47 is a heat exhaust damper that opens and closes the heat exhaust port 48 leading to the outside of the vehicle; 49 is a defroster damper that adjusts the flow rate of defroster air reaching the defroster outlet 50; 51;
is an outlet switching damper that switches between the first outlet 52 and the second outlet 53.

Next, reference numeral 25 denotes a reservoir tank, which is provided outside the circulation system to store a preliminary liquid phase refrigerant, and is opened to the atmosphere through a cap 26 having a ventilation function. At the same time, it is installed at a relatively high place in the vehicle so that the liquid level can be secured at a higher position than the uppermost end of the circulation system, that is, the discharge pipe attachment part 8a of the connecting pipe 8. An air exhaust passage 27 for discharging the air in the system is connected to the exhaust pipe attachment part 8a, and in order to recover the liquid phase refrigerant that overflows at the same time as the air is discharged.
The distal end of the air discharge passage 27 is inserted into the reservoir tank 25, and opens at a relatively upper portion thereof. and,
A normally closed first solenoid valve 28 is interposed in the air exhaust passage 27 .

Furthermore, a first auxiliary refrigerant passage 29 and a second auxiliary refrigerant passage 30 are connected to the bottom of the reservoir tank 25 . The first auxiliary refrigerant passage 29 is connected to the upstream side (suction side) of the refrigerant supply pump 4 of the refrigerant circulation passage 15 through a second electromagnetic valve 31 which is a three-way valve.

When the second solenoid valve 31 is not energized, the refrigerant circulation passage 15
Flow path A) in which the first auxiliary refrigerant path 29 and the refrigerant supply pump 4 are communicated with each other by blocking the energization, and a flow path B in which the first auxiliary refrigerant path 29 is interrupted and the refrigerant circulation path 15 is communicated with each other when energized (flow path B). It is to be maintained. The second auxiliary refrigerant passage 30 is connected to the lower tank 13 as described above, and a normally open third solenoid valve 32 is interposed in the middle thereof.

The electromagnetic valves 28, 31, 32, the refrigerant supply pump 4, the cooling fan 14, and the heater pump 18 are driven and controlled by a control device 33 using a microcomputer. A first liquid level sensor 34 provided. Temperature sensor 35. Second liquid level sensor 36 provided in the lower tank 13. Control, which will be described later, is performed based on detection signals from a negative pressure switch 37 provided at the top of the circulation system. Reference numeral 38 designates a battery, 39 an ignition switch, and 40 a heater pump.

Here, the above 1. The second liquid level sensor 34,36 is a float sensor using a reed switch, for example, and detects whether the refrigerant liquid level has reached a set level in an on/off manner. The liquid level sensor 34 has its detection level set at a height approximately in the middle of the cylinder head 6, and the second liquid level sensor 36 has its detection level set at a position slightly above the opening of the second auxiliary refrigerant passage 30. It is set in the height position. Further, the temperature sensor 35 is made of, for example, a thermistor, and is provided at a position slightly below the first liquid level sensor 34, that is, at a position normally immersed in the liquid phase refrigerant, to detect the refrigerant temperature within the water jacket 2. In addition, the negative pressure switch 37 uses a diaphragm that responds to the differential pressure between atmospheric pressure and system pressure, so whether the system is under negative pressure with respect to the atmospheric pressure in the operating environment, whether in highlands or lowlands. It detects whether or not the
The operating pressure was set to about 11 g for -50 mm.

To explain the basic cooling mechanism of the boiling cooling device configured as described above, liquid phase refrigerant is usually stored in the water jacket 2 up to a predetermined level, that is, the level set by the first liquid level sensor 34. However, when this liquid-phase refrigerant is heated by the engine's combustion heat, it starts boiling when it reaches a boiling point depending on the pressure in the system at that time, absorbs latent heat of vaporization, and evaporates. At this time, the refrigerant boils particularly actively in the high-temperature parts of the water jacket 2 and removes a large amount of heat, so areas that normally tend to reach high temperatures, such as the vicinity of the combustion chamber, are kept at a uniform temperature. This allows for efficient cooling.

The refrigerant vapor generated within the water jacket 2 is led to the condenser 3 via the vapor passage 9, where it is cooled by heat exchange with outside air and is condensed and liquefied. In this condenser 3, good heat exchange is performed between the high-temperature steam and the outside air, and the heat dissipation efficiency is extremely superior to that of a radiator of a normal water-cooled cooling device. The liquefied refrigerant is temporarily stored in the lower tank 13 at the bottom of the condenser 3, and from there is circulated and supplied to the walk jacket 2 again by the refrigerant supply pump 4 so as to keep the liquid level in the water jacket 2 above a predetermined level. Ru.

In this way, a predetermined amount of refrigerant is basically sealed in a closed circulation system from which air has been removed, and this refrigerant is circulated while repeating the cycle of boiling and condensation, thereby achieving efficient boiling cooling.

Further, when the heater switch 40 is turned on, the heater pump 18 is activated, and a portion of the refrigerant is transferred from the rad 6 side to the cylinder of the water jacket 2 into the heater refrigerant introduction passage 2.
0 to the heater core 17, where it warms the air for heating the vehicle interior and at the same time lowers the temperature due to the heat exchange. Then, the refrigerant whose temperature has decreased is exclusively directed to the lower part of the five cylinder blocks of the water jacket 2 via the refrigerant return passage 21 by the pump 18, and is used for cooling the water jacket 2 again.

Here, when the temperature of the refrigerant heater 3 and 1 is relatively low, the control valve 24 is in the state shown in FIG. Therefore, the refrigerant flows as described above, but when the refrigerant temperature exceeds a predetermined temperature, the wax 105 liquefies and expands in the control valve 24, and the elastic sleeve 104
The piston 105 is pushed out through the . However, piston 1
06 is fixed, the case 102 moves to the left in the figure and seats on the valve seat 110. That is, in the state shown in FIG. 2, the refrigerant introduction passage 20 is blocked, and the communication passage 23 becomes connected to the population 17a of the heater core 17. Then, the refrigerant whose temperature has decreased from the outlet 17b of the heater core 17 is passed through the communication path 23 by the pump 18 to the heater core 1.
The air is recirculated to the inlet 17a of the heater 3, and the temperature of the heater 3 and 1 is maintained at an appropriate temperature, thereby preventing an excessive rise in the heater outlet temperature.

On the other hand, in the reservoir tank 25 provided outside the circulation system,
A reserve liquid phase refrigerant is stored in an amount sufficient to fill the entire circulation system with water, and after the preliminary liquid phase refrigerant is introduced into the circulation system at startup and the air is discharged, the excess refrigerant is released. is returned to the reservoir tank 25, and the amount of the refrigerant enclosed is regulated to a predetermined amount. In addition, during supercooling, control is performed to narrow the heat dissipation area of the condenser 3 by introducing a preliminary liquid phase refrigerant into the system, and after that, when the temperature recovers, excess refrigerant is returned to the reservoir tank 25 to increase the amount of refrigerant sealed to a predetermined amount. stipulated in When discharging excess refrigerant and sealing the refrigerant circulation system in this way, if a sensor malfunctions or the liquid refrigerant is shifted to one side during swirling, and more than a predetermined amount of refrigerant is enclosed, normal operation will be resumed. During control, the excessive amount of refrigerant is detected and the operation of returning the surplus refrigerant to the reservoir tank 25 is performed again to avoid continued operation with an excessive amount of refrigerant.

Next, specific control executed by the control device 33 will be explained based on flowcharts shown in FIGS. 5 to 13.

FIG. 5 is a flowchart showing an overview of the control. When the control starts when the engine is started (ignition key ○N), after a predetermined initialization process (step I) is performed, the start is first started as an initial start. Specifically, it is determined whether the temperature detected by the temperature sensor 35 is higher than a set temperature (for example, 45° C.) (step 2).

If the initial startup is below the set temperature, i.e. in an unwarmed state, air discharge control (step 3) is performed, and then surplus refrigerant discharge control (
Proceed to step 4), and then proceed to normal operation control (step 5).
) and negative pressure prevention control (step 6) are repeated until the key is turned off. On the other hand, if the temperature is equal to or higher than the set temperature in step 2, that is, at the time of restart, air intrusion over time is not considered, so the process proceeds to surplus refrigerant discharge control (step 4) without performing air discharge.

Also, if a key OFF signal is input during the control,
The interrupt control routine shown in FIG. 6 is executed, and the key OF
After certain processing by Fm control (step 7), the power is turned off and the series of controls ends.

FIG. 7 is a flowchart of air exhaust control in step 3.

This indicates the yard.First, in step 11, the first solenoid valve 2 is
8, the second solenoid valve 31 is turned off (flow path A), and the third solenoid valve 32 is closed, and then the refrigerant supply pump 4 is turned on.
(Step 12). Thereby, the preliminary liquid phase refrigerant in the reservoir tank 25 is introduced into the circulation system via the first auxiliary refrigerant passage 29. This is continued for a predetermined time set by the software timer T1 in step 13, specifically, for a period of several seconds to several tens of seconds, which is set in advance to be sufficient to fill the system with water. Therefore, the air remaining in the system is collected in the upper part of the system, and then is forcibly discharged outside the system to the server tank 25 side via the air discharge passage 27.

In addition, when air disappears from the system, the air exhaust passage 2
Liquid phase refrigerant overflows from the tank 7, but all of this is collected into the reservoir tank 25. Then, after a predetermined period of time has elapsed, the refrigerant supply pump 4 is turned off (step 14).

That is, at this point, air has been completely exhausted from the circulation system including the heater core 17.

In addition, instead of the determination in step 13, a liquid level sensor is further provided at the top of the circulation system, and based on the detection of the presence or absence of the liquid level, the refrigerant supply pump 4 is driven until the system is actually full of water. It may be configured.

Figures 8 and 9 are executed in a full water state (the system is filled with liquid phase refrigerant) after air has been discharged, or in a state where part of the system is in the gas phase refrigerant region at the time of restart. The flowchart of the surplus refrigerant discharge control in step 4 is shown. Basically, the excess liquid phase refrigerant is pushed out to the reservoir tank 25 outside the system by using the vapor pressure generated by the start of boiling inside the water jacket 2. At this time, depending on various conditions, the lower tank 13 When the liquid level in the water jacket 2 (inside the cylinder head) drops to the set level first (this is usually the case during a cold start), and when the liquid level inside the water jacket 2 (inside the cylinder head) drops to the set level first ( (This condition is likely to occur when restarting), and the lower tank 13
If the liquid level in the water jacket 2 drops first, the process is mainly carried out by the procedure shown in Figure 8, and if the liquid level in the water jacket 2 drops first, the process is mainly carried out by the procedure shown in Figure 9. .

First, in step 21 of FIG. 8, the first solenoid valve 28 is closed, and the second solenoid valve 28 is closed.
The solenoid valve 31 is turned on (flow path B) and the third solenoid valve 32 is opened. As a result, the inside of the system is brought into communication with the reservoir tank 25 via the second auxiliary refrigerant passage 30. In this state, the determination in step 22 and the determination in step 29 are repeated, and the liquid level in the lower tank 13 and the water jacket 2 are
Monitor the liquid level inside.

If the liquid level in the lower tank 13 first drops to the set level due to discharge of the liquid phase refrigerant due to the generated vapor pressure, the third solenoid valve 32 is closed to prevent vapor from being discharged outside the system (step 24). , the temperature control shown in steps 25 to 28 is started. Here, the set temperature calculation in step 25 is to set a target temperature by inputting various operating condition signals of the engine. For example, in an urban driving area where emphasis is placed on improving thermal efficiency, abnormal combustion such as knocking occurs at around 110 degrees Celsius. In high load ranges where heating is easy, the temperature is set to about 100°C.

In this state, in step 29, the water jacket 2
The excess liquid phase refrigerant in the water jacket 2 is moved to the lower tank 13 in the form of [boiling in the water jacket 2 and condensation in the condenser 3].

When the liquid level in the lower tank 13 rises above the set level, the cooling fan 14 is turned off as determined in step 22.
(Step 31), open the third solenoid valve 32 (Step 32) to discharge excess liquid phase refrigerant from the lower tank 13 to the excess reservoir tank 25 outside the system. 3. Close the solenoid valve 32 (step 24). That is, this third solenoid valve 3
By repeating the opening and closing of 2, the surplus liquid phase refrigerant is gradually discharged out of the system, and then, when the liquid level in the water jacket 2 falls to a set level, the process proceeds to step 33 in FIG. Note that while the third solenoid valve 32 is closed and the system is on standby, there is a risk that the inside of the system will become overcooled due to wind from the vehicle, but the negative pressure switch 37 can be used to ensure that the inside of the system is in a negative pressure state. If detected (step 23), open the third solenoid valve 32 (step 32) and conversely open the reservoir tank 25.
A liquid phase refrigerant is introduced from the engine to restore the system pressure to approximately atmospheric pressure and prevent the engine from overcooling.

Furthermore, in step 33, if the third solenoid valve 32 is in a closed state, the control is immediately terminated, and on the other hand, if it is in an open state, it means that the liquid level in the lower tank 13 is above the set level at that point. Therefore, step 34 to step 36
While controlling the liquid level in the water jacket 2, the liquid level in the lower tank 13 is waited for to decrease, and when the liquid level has decreased to the set level (step 37), the third solenoid valve 32 is closed and the control is terminated.

When the above control is completed, a predetermined amount of refrigerant has been sealed in the circulation system, and basically the liquid phase refrigerant occupies up to the set level in the water jacket 2 and lower tank 13, and the remaining part is in the gas phase. It is filled with refrigerant.

On the other hand, if the liquid level in the water jacket 2 drops first, the determination in step 29 causes the liquid level to drop in steps 30 and 33.
The process then proceeds to step 34. Thereafter, steps 34 to 37 are repeated with the third solenoid valve 32 kept open to control the liquid level in the water jacket 2 to the set level and monitor the liquid level in the lower tank 13. and,
Similarly, when the liquid level in the lower tank 13 drops to the set level, the third solenoid valve 32 is closed (step 38) and the control is ended. Note that during standby in this case, since the circulation system is in an open state, the temperature is maintained at a constant temperature without requiring temperature control by the cooling fan 14.

Next, FIGS. 10 and 11 show a flowchart of the normal operation control in step 5, which is executed when a predetermined amount of refrigerant is sealed in the system as described above.

This normal operation control includes temperature control within the system, liquid level control that adjusts the amount of liquid phase refrigerant on the water jacket 2 side and the liquid phase refrigerant amount on the lower tank 13 side, and overflow control of the amount of refrigerant sealed in the system. It consists of refrigerant excess avoidance control and refrigerant shortage avoidance control that detects shortage and performs discharge 2 replenishment.

First, in step 41, a target temperature corresponding to the operating conditions at that time is set, and in steps 42 to 44, the cooling fan 14 is turned on so that the actual temperature is within ±0.5°C of the target temperature. OFF control.

In this boiling cooling system, the acceleration or suppression of condensation due to the presence or absence of air blowing changes the pressure within the system and immediately affects the boiling point of the refrigerant inside the walk jacket 2, so the engine temperature can be controlled extremely responsively and with high precision. can.

On the other hand, liquid level control is processed by steps starting from step 45. This is done by giving priority to maintaining the liquid level in the water jacket 2 at the set level, and only under certain conditions, allowing the liquid level in the water jacket 2 to rise above the set level and allowing the liquid level in the lower tank 13 to rise above the set level. The liquid level is also controlled. Specifically, if it is determined in step 45 that the liquid level in the water jacket 2 is below the set level, the refrigerant supply pump 4 is turned ON (step 47).
), and the liquid phase refrigerant is circulated and supplied from the lower tank 13 to the water jacket 2. The supply of the liquid phase refrigerant is continued at least thereafter until it is determined in step 45 that the liquid level in the water jacket 2 has reached the set level.

If the system temperature substantially matches the target value when the set level is reached (step 50), the refrigerant supply pump 4 is immediately turned off (step 54) without considering the liquid level in the lower tank 13. However, if the system temperature is 1.5°C or more higher than the target value in step 50, step 5
1-Step 52-Step 47 to remove lower tank 1.
3 Refrigerant supply pump 4 until the internal liquid level drops to the set level.
(at the same time, the liquid level in the water jacket 2 becomes higher than the set level). This is because even if the liquid level in the water jacket 2 is kept constant, if the proportion of vapor bubbles in the liquid phase refrigerant in the water jacket 2 increases due to changes in the boiling state, the liquid level in the lower tank 13 will increase. The hot water temperature in the system may reach the target value +1.
When the temperature is 5°C or higher, the liquid level on the capacitor 3 side is forcibly lowered to expand the heat dissipation area.

Next is the overfill avoidance control, which uses the above-mentioned liquid level control to detect an overfill. Specifically, under the constant temperature condition (step 50) as described above, the stage 51 is
Based on the 0 determination, the refrigerant supply pump 4 is driven with the liquid level in the lower tank 13 as the control target, but in step 52
So that pump is on! The continuous opening period is monitored by a software timer T2, and when it is longer than a set time, for example, 10 seconds, it is determined that the amount of refrigerant enclosed is excessive.

That is, when only the liquid level on the water jacket 2 side is controlled, all the excess liquid phase refrigerant in the case of excess refrigerant is unevenly distributed on the lower tank 13 side, and this is removed by driving the refrigerant supply pump 4. Since the refrigerant must be moved to the jacket 2 side, if the refrigerant takes an excessively long time to move, the amount of refrigerant sealed in the refrigerant is too large. If it is determined that the amount is excessive, steps 56 to 11 in FIG.
At step 58, the refrigerant supply pump 4. After stopping the cooling fan 14 and clearing the software timer T2, the process again proceeds to the above-mentioned surplus refrigerant discharge control (FIG. 8).

As a result, the amount of enclosed refrigerant is adjusted again according to the processing procedure described above, and the excess refrigerant that was present in the system is discharged to the reservoir tank 25.

As described above, by avoiding excess refrigerant, it is possible to prevent a phenomenon in which a large amount of liquid refrigerant flows into the condenser 3 from the water jacket 2 together with steam and reduce the heat dissipation efficiency, resulting in poor cooling and cooling fan 14. This can prevent an increase in driving frequency.

In addition, when the heat dissipation efficiency decreases due to an excessive amount of refrigerant, the temperature inside the system tends to rise, and as a result, the above-mentioned expansion control of the heat dissipation area of the condenser 3 is always performed, and at that time, an excessive amount of refrigerant can be detected. Therefore, excessive amount of refrigerant can be avoided reliably and rationally. Incidentally, the reason why the enclosed refrigerant becomes excessive is that the third solenoid valve 3
When sealing the refrigerant circulation system by 1. The second liquid level sensors 34 and 36 malfunctioned due to vibrations or the like, or the liquid phase refrigerant was biased to one side due to sudden stops or sharp turns of the vehicle, resulting in erroneous detection.

On the other hand, in this embodiment, in addition to avoiding an excessive amount of sealed refrigerant, an insufficient amount of the refrigerant is also avoided. The reason why the amount of refrigerant enclosed is too little is not only erroneous detection similar to the case of too much, but also the amount of refrigerant may gradually become insufficient due to leakage of the refrigerant from the seal portion.

This is done in step 4 when the liquid level in the water jacket 2 falls below the set level in the liquid level control described above.
Based on the determination in step 5, the refrigerant supply pump 4 is set to ○N, but at this time, in step 46, the duration of the state below the set level is monitored by a software timer T,
If this is longer than the set time, for example 10 seconds, it is determined that the amount of refrigerant enclosed is too small and the second solenoid valve 31 is turned off.
(flow path A) (step 55). That is, the above set time is a value set in consideration of the responsiveness of the control system when the amount of refrigerant enclosed is appropriate, and will not be exceeded if the amount of refrigerant is sufficient.

Incidentally, if it is to be carried out more strictly, the above-mentioned time may be set variably by adding conditions such as load.

Then, when the second solenoid valve 31 is set to the flow path A as described above, the refrigerant supply pump 4 is simultaneously turned on (step 47).
Therefore, the reserve liquid phase refrigerant in the reservoir tank 25 is forcibly replenished into the system. This continues until the liquid level in the water jacket 2 reaches the set level. When the set level is reached, step 48. Step 4
9, replenishment is stopped and the software timer T3 in step 46 is cleared.

As mentioned above, avoidance of refrigerant shortage is achieved by
Since the refrigerant is replenished as needed every time the refrigerant is circulated from the refrigerant 3 to the water jacket 2, there is no possibility that the combustion chamber wall will be exposed due to insufficient amount of refrigerant.

Next, FIG. 12 shows a flowchart of the negative pressure prevention control (step 6) that is performed following the above-mentioned normal operation control (step 5). This is to prevent the supercooling phenomenon caused by reduced pressure boiling when the wind in the vehicle is too strong, and the temperature inside the system is 97°C or less (step 61) and the temperature inside the system is actually relative to the outside pressure. This is performed on the condition that the pressure is negative (step 62). Furthermore, if the boiling point of the refrigerant under atmospheric pressure is 100°C or higher (such as when antifreeze is added to water), it is impossible to control the temperature around 100°C with the system closed using only pressure conditions. In addition, if only the temperature conditions are used, there is a risk that steam will be ejected when the system is opened due to changes in external pressure.

If both of the above conditions are met, the third solenoid valve 32 is opened in step 63 to bring the system into communication with the reservoir tank 25. As a result, liquid phase refrigerant is introduced from the reservoir tank 25 into the negative pressure system, and as a result, the pressure in the system is restored to approximately atmospheric pressure, and as a result, the water jacket 2
The boiling point of the liquid phase refrigerant in the tank increases. Also, step 64
- Since the liquid level in the water jacket 2 continues to be controlled at the set level in step 66, only the liquid level in the condenser 3 is raised by the liquid phase refrigerant flowing from the reservoir tank 25. Therefore, the amount of heat dissipated from the capacitor 3 decreases, and the liquid level within the capacitor 3 naturally fluctuates up and down to balance the amount of heat generated by the engine.

The system open state described above continues until the system becomes positive pressure (step 67) and the liquid level in the lower tank 13 falls to the set level (step 68). In other words, when the engine heat generation increases due to a decrease in vehicle running wind or an increase in load, the liquid phase refrigerant is gradually discharged from the system due to the increase in vapor pressure, and when the liquid level in the lower tank 13 drops to the set level, the 3 Close the solenoid valve 32 (step 69),
This negative pressure prevention control is ended. As a result, the refrigerant circulation system is again sealed with a predetermined amount of refrigerant, and the above-mentioned normal operation control (FIG. 10) is repeated again. If there is an excess or deficiency in the enclosed refrigerant due to erroneous detection or the like when the refrigerant circulation system is closed as described above, the above-mentioned refrigerant shortage avoidance and excess refrigerant avoidance are also used to handle the problem.

FIG. 13 shows key OFF control (step 7) which is interrupted when the engine ignition key is turned OFF.
) is shown.

First, by determining the temperature in step 74, if the hot water temperature in the system is relatively low (for example, below 75°C), the power is immediately turned off.
(Step 83) However, if the temperature is higher than this, the software timer T4 is set to drive the cooling fan 14 for a maximum of 10 seconds to force cooling (Steps 76 to 83).
Step 78) and waits until the system cools down to negative pressure (step 82).

Also, during this time, control of the liquid level in the water jacket 2 is continued (steps 79 to 81). Then, when the pressure inside the system becomes negative, the power is turned off (step 83), and the entire series of controls is completed. This electricity t1. When OFF, the normally closed first solenoid valve 28 is closed, and the second solenoid valve 31 is closed.
is in the flow path A, and the third electromagnetic valve 32, which is a normally open type, is opened, so that as the temperature in the system decreases, that is, the pressure decreases, the preliminary liquid phase refrigerant flows from the reservoir tank 25 through the second auxiliary refrigerant path 30. is introduced, and eventually the entire system is filled with liquid phase refrigerant in preparation for the next startup. Furthermore, when introducing the above-mentioned preliminary liquid phase refrigerant, it flows into the system from the lower tank 13 via the core section 12, so a small amount of air may enter the condenser tube for some reason during operation. Even if it adheres, 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 84 based on the judgment in step 73, and based on the information G saved in advance (step 71). , to return to the control state that was in progress before the key was turned off.

In this embodiment, wax is used as the control valve 24, but bimetal may be used instead.

In addition, by making the temperature sensor and valve independent and using a solenoid valve,
The flow rate ratio may be controlled by duty control, for example, in response to a signal from a temperature sensor.

Further, in this embodiment, the refrigerant is returned from the heater core 17 to the chrysodar block 5 side of the water jacket 2, but it may be returned to the cylinder head 6 side to enhance the cooling effect of the cylinder head 6.

By the way, in this embodiment, the water jacket 2
．． The refrigerant circulation system consisting of the condenser 3 and the refrigerant supply pump 4, together with the refrigerant circulation system to the heater core 17, is a closed circulation system during normal operation.

This is due to the following reason.

In recent years, for example, in Japanese Patent Application Laid-Open No. 57-62912,
Although it has already been mentioned that a boiling cooling device has been proposed, it has not yet been put into practical use.

The biggest problem is that it is difficult to completely remove air, which is a non-condensable gas, from the refrigerant circulation system, and the residual air can significantly reduce cooling performance and reduce the heat exchange efficiency in the heater core. That's true. That is, in the system described in the above publication, a part of the refrigerant circulation system is open to the atmosphere, and air is pushed out of the system by the generated vapor pressure, so the vaporized refrigerant flows out, and It is not always possible to completely remove the air, and especially when the capacitor core or heater core is made of a highly efficient fine tube, air tends to remain inside the core.

Moreover, in systems where the refrigerant circulation system is opened to the atmosphere in this way, the boiling point of the refrigerant in the water jacket is fixed, which not only makes it impossible to control the temperature according to engine operating conditions, but also The refrigerant temperature rises slowly, making it difficult for the engine temperature to stabilize.

For this reason, refrigerant at a sufficient temperature is not supplied to the heater core immediately after startup, and the temperature of the supplied refrigerant is not stable even after the temperature rises, so stable heating performance with a good start-up cannot be obtained. In particular, in a configuration like the one described in the above publication, in which the liquid phase refrigerant is naturally circulated between the water jacket and the separation tank and vapor is extracted from the top of the separation tank, the liquid phase refrigerant in the separation tank is also drained during a cold start. Unless the temperature of the entire refrigerant including the refrigerant is raised to near the boiling point, sufficient steam will not be supplied to the heater core, and therefore heating performance will not start up well.

Therefore, in this embodiment, a closed circulation system is configured during normal operation, and air, which is a non-condensable gas, can be reliably removed from the circulation system, thereby improving the reliability and stability of cooling performance. Although the heating performance varies depending on the load, a stable high-temperature refrigerant is always supplied to the heater core, so that stable and sufficiently hot air with a good start-up can be obtained.

In order to realize the above-mentioned closed circulation system, the following configuration is adopted as is clear from the description of the embodiments. That is, a reservoir tank provided outside the circulation system and storing a preliminary liquid phase refrigerant, a refrigerant introduction means for introducing the liquid phase refrigerant for air discharge from the reservoir tank into the circulation system, and this refrigerant a refrigerant discharge means for discharging excess refrigerant from the introduced circulation system to the reservoir tank 25 while leaving a predetermined amount of refrigerant; and a refrigerant discharge means connected to the top of the circulation system and opened when the refrigerant is introduced; By providing an air exhaust passage that is closed during exhaust, it is possible to reliably remove non-condensable gas air from within the circulation system, achieving a closed circulation system and improving the reliability and stability of cooling performance. The aim is to improve heating performance and heating performance. However, the system configuration of the closed circulation system is not limited to this, for example,
No. 8-228145 or patent application No. 140378/1984
It may be configured as shown in No.

<Effects of the Invention> As explained above, according to the present invention, it is possible to control the temperature of the refrigerant supplied to the heater core to be substantially constant, and it is possible to obtain a sufficient heating effect using the boiling cooling device under normal conditions. Of course, this has the effect of preventing overheating during high-load operation and ensuring comfortable heating in the vehicle interior at all times.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the evaporative cooling device according to the present invention, Fig. 2 (0) is a cross-sectional view of the control valve shown in each operating state, and Fig. 3 is a sectional view of the control valve in Fig. 2 [F]. FIG. 4 is a configuration diagram showing an example of an air conditioner in which a heater core is incorporated, and FIGS. 5 to 13 are flowcharts showing control details in this embodiment. 1... Internal combustion engine 2... Water jacket 3.
...Condenser 4...Refrigerant supply pump 7...Steam outlet 8...Connecting pipe 9...Steam passage 13...
...Lower tank 14...Cooling fan 15...
・Refrigerant circulation passage 17... Heater core 1 day...
・Heater pump 19...refrigerant outlet 20・
・・Refrigerant introduction passage 21 ・・Refrigerant return passage 22 ・・
・Refrigerant return port 23...Communication path 24...Control valve 25...Reservoir tank 27...Air discharge passage 28.31.32...Solenoid valve 33...Control device 34...No. 1 Liquid level sensor 35...Temperature sensor 36...2nd liquid level sensor 105...Wanox Figure 2 (A) Figure 2 (B) Figure 3 Figure 5 Figure 6 Figure 7

Claims (3)

[Claims] (1) A water jacket of the engine having a steam outlet at the top, a condenser connected to the steam outlet and having a refrigerant tank for temporarily storing liquefied refrigerant at the bottom, and a condenser provided between the refrigerant tank and the water jacket. A evaporative cooling system for an internal combustion engine for an automobile, comprising a refrigerant supply pump and a refrigerant supply pump, a heater core for heating a passenger compartment connected to a refrigerant outlet from the water jacket, and a refrigerant return port to the heater core and the water jacket. and a control valve that controls the flow rate of the refrigerant flowing through the communication path in accordance with the temperature of the refrigerant. A boiling cooling device for an internal combustion engine for an automobile, comprising: (2) A refrigerant circulation system including a water jacket, a condenser, and a refrigerant supply pump of the engine constitutes a closed circulation system during normal operation, together with a refrigerant circulation system to the heater core. Boiling cooling system for automotive internal combustion engines. (3) The boiling cooling device for an internal combustion engine for an automobile as set forth in claim 1 or 2, wherein the refrigerant outlet is provided on the cylinder head side of the water jacket of the engine.