JPS6183429A - Refrigerant temperature controller in evaporative cooling device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To make refrigerant temperature controllable at will, by detecting liquid phase refrigerant temperature inside a refrigerant circulation closed circuit, while selectively operating a valve and an auxiliary refrigerant feeding device lying between a reservoir tank and a condenser lower part. CONSTITUTION:Liquid phase refrigerant temperature inside a refrigerant circulation closed circuit D is detected by a detecting device K, and when a value below a first setting temperature is detected, there is provided with a condenser inner liquid level upping control device L which operates a solenoid valve F, interconnecting a reservoir tank E and the lower part of a condenser B, and an auxiliary refrigerant feeding device H in a selective manner. With this constitution, a radiating area of the condenser B is varied to some extent whereby radiating efficiency is adjusted for increase or decrease, thus refrigerant temperature is controllable at will.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention stores a liquid phase refrigerant in a cooling jacket,
The internal combustion engine is cooled by vaporization of the boiling point, and the generated refrigerant vapor is condensed in a condenser and reused.For details, please refer to the refrigerant temperature control device for the boiling cooling system of the internal combustion engine. The present invention relates to a device for preventing overcooling of refrigerant temperature.

<Prior art> As is well known, the temperature of an internal combustion engine not only directly affects the engine's thermal efficiency, charging efficiency, and anti-knock performance, but also affects friction loss due to oil viscosity, and affects the engine's fuel consumption rate and maximum output. ,
Alternatively, it becomes a factor that influences the level of noise. However, in conventional general water-cooled cooling devices, Y! It merely prevents excessive cooling during operation, and it is as if there is no temperature control.

In addition, even if you try to control the temperature by turning the electric fan on and off, a large amount of cooling water is circulating in the cooling system, and you have to wait for the overall temperature to change. It is impossible to follow the target temperature variably set with good responsiveness, and highly accurate temperature control that takes into account the above-mentioned thermal efficiency and the like cannot be achieved at all.

On the other hand, in contrast to the above-mentioned cooling devices that utilize simple temperature changes in cooling water, various cooling devices that utilize phase changes between liquid and gas phases of refrigerant (cooling water) have also been proposed (for example, the Publication No. 57-57608 1, JP 57-62912
Publications, etc.).

This basically boils the liquid phase refrigerant stored in the cooling jacket and transfers the generated vapor to the external condenser (
radiator), the heat is radiated and liquefied, and then the heat is liquefied and then circulated and supplied again into the cooling jacket.The temperature of each part in the cooling jacket can be uniformly maintained at the boiling point of the refrigerant, and the heat exchange efficiency in the condenser can be improved by reducing the latent heat of condensation. It has been pointed out that there are advantages that can be dramatically improved by using it.

When utilizing phase change in this way, the boiling point of the liquid refrigerant can be arbitrarily and rapidly changed by variable control of the pressure inside the cooling jacket, so the temperature can be adjusted with good responsiveness according to the operating conditions. There is a possibility that control can be realized.

<Problems to be solved by the invention> However, in conventional cooling devices of this type, the fact that the temperature immediately changes depending on the system pressure as described above actually makes it difficult to put this type of cooling device into practical use. This was considered a major drawback. In other words, in a configuration in which the inside of the cooling system consisting of a cooling jacket, condenser, etc. is sealed, the amount of heat generated by the engine changes over a wide range when applied to an automobile engine, for example.
Moreover, since the heat dissipation capacity of an efficient capacitor is almost entirely controlled by the magnitude of the vehicle running wind, the balance between the two is easily disrupted, and this immediately appears as a temperature change. It is impossible to control it by changing it slightly.

Therefore, as seen in the above-mentioned prior document, in conventional devices, a part of the cooling system is communicated with the atmosphere to create a substantially non-sealed structure, and the boiling point of the refrigerant is fixedly maintained at atmospheric pressure. As a result, temperature control according to the operating conditions as described above has not been realized.

However, it is still desirable to configure the boiling cooling system with a closed structure, that is, a closed circuit, and to freely control the engine temperature according to the engine operating state by changing the system pressure to raise or lower the refrigerant boiling point. Needless to say.

Therefore, the present inventors have provided a boiling cooling device that can configure a closed refrigerant circulation circuit in a normal operating region, and in particular, allows the refrigerant temperature to be freely controlled by preventing the refrigerant boiling point temperature from decreasing too much. The purpose is to

<Means for Solving the Problems> To this end, in the present invention, as shown in FIG. A closed refrigerant circulation path is provided in which a condenser B in which a phase refrigerant is stored in the lower part and a liquid phase refrigerant circulation means C are interposed, and the latent heat of the vapor phase refrigerant absorbed by the cooling jacket A and evaporated is radiated in the condenser B. and a first auxiliary refrigerant that communicates between the reservoir tank E and the lower part of the condenser B via a solenoid valve F. A passage G, a second auxiliary refrigerant passage I that communicates the reservoir tank E and the lower part of the condenser B via an auxiliary refrigerant supply means H, and a pressure detection means J that detects the pressure in the closed refrigerant circulation circuit. , temperature detection means for detecting the temperature of the liquid phase refrigerant in the refrigerant circulation closed circuit, and when the temperature detection means K detects a temperature equal to or lower than the first set temperature T1, the electromagnetic valve F and the auxiliary refrigerant supply means H a liquid level rise control means in the capacitor that selectively operates the liquid level rise control means in the capacitor, the liquid level rise control means in the capacitor satisfies the temperature condition and the pressure detection means J falls below a predetermined value P. a first control means L+ that opens the electromagnetic valve F when detecting a rotating pressure;
When the above positive pressure is detected, and the pressure detection means J detects a pressure lower than the predetermined value P, and the temperature detection means K detects a second set temperature T lower than the first set temperature T1.
2 or less, the second control means L2 operates the auxiliary refrigerant supply means H when the refrigerant supply means H is detected.

Therefore, according to this configuration, the refrigerant temperature is equal to the first set temperature T.
, if the pressure has decreased below a predetermined value P1, the pressure within the refrigerant circulation closed circuit is monitored, and if the pressure is below a predetermined value P1, the first control means opens the solenoid valve F. , the reserve liquid phase refrigerant in the reservoir tank E is replenished into the condenser B by the differential pressure, and the refrigerant liquid level in the condenser B is raised.

However, if the differential pressure is small due to a malfunction of the detected pressure, or if the refrigerant is not replenished sufficiently due to a failure or clogging of the solenoid valve F, the refrigerant temperature drops below the second set temperature T2. The second control means operates the auxiliary refrigerant supply means H to forcibly replenish the preliminary liquid phase refrigerant in the reservoir tank E into the condenser B to further raise the refrigerant liquid level in the condenser B. . If the pressure is a positive pressure equal to or higher than the predetermined value 21, opening the solenoid valve F will only cause the liquid phase refrigerant in the condenser B to flow back into the reservoir tank E. Therefore, the solenoid valve F is closed and the second The control means L2 operates the auxiliary refrigerant supply means H to forcibly replenish the auxiliary refrigerant into the condenser B.

Since the operation of the auxiliary refrigerant supply means H is likely to result in energy loss, we would like to use the first auxiliary refrigerant passage G, which can replenish refrigerant by differential pressure simply by opening the solenoid valve, as much as possible, but when such inconvenience occurs or the first auxiliary refrigerant passage G becomes unavailable. Sometimes the second auxiliary refrigerant passage I is used. In this way, by controlling the level of liquid refrigerant in the condenser to increase, the heat dissipation area of the condenser is changed to increase or decrease the heat dissipation efficiency, thereby changing the system pressure of the closed circuit and causing an excessive drop in the boiling point of the refrigerant. This prevents this and obtains the desired refrigerant temperature. As a result, refrigerant temperature control, especially control to prevent excessive low temperatures, can also be performed by controlling the rise in the liquid level of the liquid phase refrigerant stored at the bottom of the condenser, making it possible to sufficiently compensate for the adverse effects of changes in running air volume. Therefore, the refrigerant circulation circuit is configured as a closed circuit to prevent an excessive drop in the refrigerant temperature of an automobile internal combustion engine in which the engine heat value varies over a wide range.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows the configuration of one embodiment of the present invention, in which an internal combustion engine 1 has a cooling jacket 2 which is filled with a predetermined amount of liquid phase refrigerant during operation.
The cooling jacket 2, a condenser 3 for condensing a gas phase refrigerant, and an electric refrigerant circulation pump 4 are connected to form a refrigerant circulation closed circuit.

The cooling 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, communicates through each cylinder. At the same time, a steam ratio lower is provided at an appropriate position above it. The steam ratio lower communicates with the upper inlet of the condenser 3 via a connecting pipe 8 and a steam passage 9. The connecting pipe 8 is formed with a discharge pipe mounting part 8a which is the uppermost part of the refrigerant circulation system and stands upwardly, and the upper end opening thereof is sealed by a cap.

The condenser 3 is composed of an upper tank 11 having the above-mentioned inlet, a core section 12 mainly consisting of fine vertical tubes, and a lower tank 13 that temporarily stores the liquefied refrigerant condensed in the core section 12. The cooling fan 14 is installed at a position such as the front of the vehicle that receives wind from the vehicle running, and is further provided with an electric cooling fan 14 for forced cooling on the front or back side.

Further, the lower tank 13 is connected to one end of a refrigerant circulation passage 15 at a relatively lower portion thereof, and one end of a first auxiliary refrigerant passage 16 is connected to an upper portion thereof. Said refrigerant! The other end of the ring passage 15 is connected to the refrigerant port 2a provided on the cylinder head 6 side of the cooling jacket 2, and the ring passage 15 is equipped with a three-way type second solenoid valve 17 in the middle part, and is connected to the second solenoid valve 17. A refrigerant circulation pump 4 is interposed between the lower tank 13 and the lower tank 13 . Above cooling jacket 2. Condenser 3° Refrigerant circulation pump 4. During normal operation, the refrigerant circulation circuit formed by the path of the cooling jacket 2 causes a refrigerant, for example, water with some additives added, to circulate while repeatedly boiling and condensing.

A reservoir tank 21, which is provided outside the closed circulation circuit and stores a preliminary liquid phase refrigerant, is open to the atmosphere through a cap 22 having a ventilation function, and is located at approximately the same height as the cooling jacket 2. The first auxiliary refrigerant passage 16 and the second auxiliary refrigerant passage 23 are connected to the bottom thereof. and the first auxiliary refrigerant passage 16
A normally open third solenoid valve 24 is interposed in the passage. Further, the second auxiliary refrigerant passage 23 is connected to the second solenoid valve 17.
It is connected to the refrigerant circulation passage 15 via. When the second solenoid valve 17 is not energized, it blocks the refrigerant circulation passage 15 and establishes communication between the reservoir tank 21 and the lower tank 13 (flow path A), and when it is energized, it blocks the second auxiliary refrigerant passage 23. The refrigerant circulation passage 15 is placed in a communicating state (flow path B).

The refrigerant circulation pump 4 is one that can pump the liquid phase refrigerant in both forward and reverse directions.If the refrigerant circulation pump 4 is driven in the forward direction in the state of the flow path A described above, the refrigerant is pumped from the lower tank 13 to the reservoir tank. The liquid phase refrigerant can be forcibly discharged to the reservoir tank 21, and the liquid phase refrigerant can be forcibly introduced from the reservoir tank 21 to the lower tank 13 by driving in the opposite direction. Therefore, the second
When the solenoid valve 17 takes the flow path A, the refrigerant circulation pump 4
The reversing action of and the second solenoid valve 17 function as auxiliary refrigerant supply means. In addition, in the state of flow path B, the refrigerant circulation pump 4
When driven in the forward direction, it functions as a liquid phase refrigerant circulation means that circulates and supplies liquid phase refrigerant from the lower tank 13 to the cooling jacket 2. These liquid phase refrigerant circulation means and auxiliary refrigerant supply means may be provided in separate systems.

On the other hand, an air discharge passage 25 for discharging air in the system is connected to the discharge pipe attachment part 8a which is the top of the refrigerant circulation closed circuit described above, and when air is discharged, the air discharge passage 25
In order to recover the liquid phase refrigerant simultaneously overflowing from the air discharge passage 25, the tip of the air discharge passage 25 is opened into the reservoir tank 21. A normally closed first solenoid valve 26 is interposed in the air exhaust passage 25 .

The electromagnetic valves 26, 17, 24, the refrigerant circulation pump 4, and the cooling fan 14 are controlled by a control device 31 using a so-called microcomputer system (condenser liquid level rise control means having first and second control means to be described later). (including), specifically the cooling rack,
The first liquid level sensor 32 provided in the soto 2. temperature sensor 33,
Control described later is performed based on detection signals from a second liquid level sensor 34 provided in the lower tank 13 and a pressure sensor 35 provided at the top of the circulation circuit.

Here, the above-mentioned 1. The second liquid level sensor 32,34 is a float type sensor using a reed switch, for example, and detects whether or not the refrigerant liquid level has reached a set level in an on/off manner. The detection level of the sensor 32 is set at a height approximately in the middle of the cylinder head 6, and the detection level of the second liquid level sensor 34 is set at a height slightly above the opening of the first auxiliary refrigerant passage 16. set in position. Further, the temperature sensor 33 that functions as a liquid phase refrigerant temperature detection means is made of, for example, a thermistor, and is located slightly below the first liquid level sensor 32;
That is, it is usually provided at a position immersed in the liquid phase refrigerant, and detects the temperature of the liquid phase refrigerant inside the cooling jacket 2. The pressure sensor 35 uses a diaphragm that responds to the differential pressure between the atmosphere and the internal pressure of the refrigerant circulation system, and the pressure sensor 35 uses a diaphragm that responds to the pressure difference between the atmosphere and the internal pressure of the refrigerant circulation system. , constitutes a pressure detection means of the refrigerant circulation closed circuit that detects whether or not the positive pressure is above. The predetermined value P1 is a value near atmospheric pressure, and it may be said that it actually detects whether the pressure is positive or negative. Other various sensors as means for detecting the engine operating state, such as an engine rotation sensor and an engine suction negative pressure sensor, are not shown.

3 to 12 are flowcharts showing the details 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 26, 17, and 24 are abbreviated as "Solenoid valve ■", "Solenoid valve ■", etc., respectively, and the liquid level inside the cooling jacket 2 is expressed as rC/H. It is abbreviated as "internal fluid level".

FIG. 3 is a flowchart showing an outline of the control. When the control starts when the engine is started (ignition key turned on), it is determined whether to initialize the SL or to restart the engine. Specifically, in S2, it is determined whether the temperature detected by the temperature sensor 33 is higher than a predetermined temperature (for example, 45° C.). Here, if the temperature is below a predetermined temperature, that is, the initial start is in a cold state, the process goes through the air discharge control in S3 and then the warm-up control in S4, and when the warm-up is completed, the temperature control in step 35 is entered. In this case, in S6, it is determined whether the refrigerant liquid level in the cooling jacket 2 is higher than a set value, and in S7, the second. The third electromagnetic valve 17.24 is switched and controlled to control the refrigerant level 88 in the cooling jacket 2. In S9, the refrigerant temperature is determined, and along with the temperature control by cooling fan control performed in S5, SIO, S11. At 512, the liquid level in the capacitor is controlled to increase or decrease.

Next, if it is determined in step 313 that the refrigerant temperature is abnormally high and that the temperature inside the cooling system is 21 or higher, step S14
High temperature avoidance control is performed at These control loops from 85 to S14 are repeated until the ignition key is turned off.

On the other hand, if the refrigerant temperature is higher than the predetermined temperature in S2, it is determined that it is time to restart, and in this case, it is unlikely that air will enter the cooling system over time, so the air exhaust control in S3 will be omitted. do.

Also, if a key-off signal is input during this control, the fourth
The interrupt control routine shown in the figure is executed. The interrupt control routine will be described later.

Figure 5 shows a flowchart of air exhaust control in S3. When the engine is started, the system is usually almost filled with liquid phase refrigerant (for example, a mixture of water and antifreeze), and the reservoir tank 21 has more liquid phase than can completely fill the system. Refrigerant is stored. Air discharge control is to discharge air by further filling the system completely with water from this state. First, in S31, the first
The solenoid valve 26 is opened, the second solenoid valve 17 is controlled to be in the flow path A, and the third solenoid valve 24 is to be closed, respectively, and the refrigerant circulation pump 4 is started to be driven in the reverse direction in S32.

Thereby, the liquid phase refrigerant in the reservoir tank 21 is introduced into the system via the second auxiliary refrigerant passage 23. This is S33
This continues for a predetermined period of time, specifically for a period of several seconds to several tens of seconds, which is set in advance on the program timer (2), which is 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 passed through the air exhaust passage 25 to the reservoir tank 2 outside the system.
1 is forcibly ejected. When a predetermined period of time has elapsed, the refrigerant circulation pump 4 is turned off at 334, the program timer (3) is cleared at 335, and the process proceeds to warm-up control (S5) shown in FIG.

In Sato 1311 eel warm-up control, 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 cooling jacket 2 rises quickly. It will soon begin to boil.

The warm-up control is basically to wait while keeping the lower tank 13 and the reservoir tank 21 in communication until the refrigerant temperature in the cooling jacket 2 rises to the target temperature (set value). 1 Close the solenoid valve 26,
The second solenoid valve 17 is used as the B flow path, and the third solenoid valve 24 is kept open.

At 343, the actual detected temperature detected by the temperature sensor 33 is compared with the set temperature set at 342, and when the detected temperature becomes "set temperature + 2.0 degrees Celsius (=α3)", 3
At step 45, the third solenoid valve 24 is closed to seal the system, and the control ends.

On the other hand, during this warm-up control, the inside of the system is released to atmospheric pressure, so if the set temperature exceeds approximately 100°C,
Due to the generated vapor pressure, the liquid phase refrigerant in the system is transferred to the reservoir tank 2.
As a result, the liquid level in the cooling jacket 2 and the liquid level in the lower tank 13 decrease excessively before the refrigerant temperature reaches the set temperature.

To deal with this, when the liquid level of either one falls below the set level of the first liquid level sensor 32 or the second liquid level sensor 34, that is, when the answer is NO in S44, the
At step 45, the system is sealed and this control is completed.

After the warm-up control is completed, the control loop from 85 to S14 is repeated as described above. By controlling the fan shown in Fig. 7 and circulating supply of liquid phase refrigerant, the liquid level in the cooling basin 7) 2 is maintained at a set level or higher.Liquid level control shown in Fig. 3 88 (Cylinder head liquid level drop abnormality check control ) (Fig. 8) and the capacitor liquid level lowering control (Fig. Figure 10) and Figure 3 512
Liquid level rise control in the capacitor according to the present invention (Fig. 11)
It is broadly divided into.

First, as mentioned above, in the warm-up control shown in Fig. 6, we will explain the case where the detected temperature is "set temperature + 2.0°C (=α,)" and the control loop is started. 352. In S53, the cooling fan 14 is turned on, and the upper limit temperature "set temperature +
2.0℃ (= α3)'', so immediately
Enter the condenser liquid level lowering control as shown in the figure.

(Condenser internal liquid level lowering control) This condenser internal liquid level lowering control is performed by forcibly discharging the liquid phase refrigerant in the condenser 3 to the reservoir tank 21 by the refrigerant circulation pump 4 in S61. 562), lowering the liquid level in the capacitor 3 to expand the heat dissipation area of the capacitor 3,
It increases the heat dissipation ability, and its discharge is when the detected temperature is "
The process continues until the temperature drops to the set temperature + 1.0°C (=α,) (S68. 569), and finally the system is sealed at 570 and the process ends. The above end temperature is the upper limit temperature of S9 "set temperature + 2" which is a condition that depends only on the cooling fan 14.
．． 0℃ (=α3)" and the lower limit temperature "Set temperature -4.0℃
(=α4)" and slightly higher than the set temperature, this is done in consideration of the responsiveness of temperature change to a drop in the liquid level.

The set temperature (set value) of the liquid phase refrigerant is mechanically set at any time based on the relationship between the engine rotation speed and the load (in the case of an electronic fuel injection internal combustion engine, the load is detected by the injection pulse width, etc.)
.

(Abnormality check control for low refrigerant liquid level in cooling jacket) On the other hand, the refrigerant in the condenser 3 is transferred to the reservoir tank 21.
Since the refrigerant continues to boil within the cooling jacket 2 even while being discharged into the cooling jacket 2, its liquid level gradually decreases. If the liquid level on the cooling jacket 2 side falls below the set level, this is judged at 355 in Fig. 8, and the abnormality check system wJ for lowering the refrigerant liquid level in the cooling jacket 2 at 358 (Fig. 9) is performed.
I do.

That is, if the liquid level in the cooling jacket 2 has decreased within a predetermined time, for example, 10 seconds according to the program timer (871), the process proceeds to S72, where the refrigerant circulation pump 4 is rotated in the forward direction, and the second solenoid valve 17 is closed to the flow path B. , the third electromagnetic valve 24 is closed, liquid phase refrigerant is temporarily replenished from the condenser 3 to the cooling jacket 2, and the liquid level in the cooling jacket is controlled to the level set by the first liquid level sensor 32.

If 371, the refrigerant liquid level in the cooling jacket decreases by 10~
If it is found that it has continued for 20 seconds or more, it is determined that there is an abnormality, and the refrigerant in the lower tank 13 of the condenser 3 is controlled to be supplied with the refrigerant, and the refrigerant in the lower tank 13 is supplied to the cooling jacket 2. That is, in S73, it is determined by the pressure sensor 35 whether the pressure inside the system has fallen below a predetermined positive pressure of 20 or more. If the pressure decreases (substantially negative pressure), the second solenoid valve 17 is activated in S75.
B flow path, the third solenoid valve 2 with the refrigerant circulation pump 4 in normal rotation.
4 is opened, the preliminary liquid phase refrigerant in the reservoir tank 21 is introduced into the lower tank 13 of the condenser 3 due to the pressure difference, so that the liquid level of the liquid phase refrigerant in the condenser 3 is prevented from decreasing and at the same time. The refrigerant is replenished from the lower tank 13 into the cooling jacket 2, raising the refrigerant liquid level in the cooling jacket 2 and returning it to the level set by the first liquid level sensor 32.

If it is found in S73 that the temperature in the system is 21 or higher, then in S74 the program timer ② indicates that if the liquid level continues to be abnormally low within the range of 10 to 20 seconds, the second solenoid valve 17 is activated. The refrigerant circulation pump 4 is reversed while switching to the A flow path and closing the third solenoid valve 24.

As a result, the reserve liquid phase refrigerant in the reservoir tank 21 is forcibly pumped and replenished into the condenser 3 by the refrigerant circulation pump 4, and the refrigerant liquid level in the lower tank 13 is raised.

Next, even after the refrigerant liquid level in the cooling jacket 2 which is at 21 or higher falls below a predetermined level and the above-mentioned refrigerant liquid level increase control in the condenser is performed for 10 to 20 seconds, the liquid level in the cooling jacket 2 still remains. is less than the set value, S76
Proceed to S72 to clear the program timer ■, return to 371, and then proceed to S72 again within 10 seconds to transfer the refrigerant supplied from the lower tank 13 of the condenser to the cooling jacket 2.
supply within.

These repeated actions prevent an abnormal drop in the liquid level in the cooling jacket 2 and at the same time prevent an abnormal drop in the refrigerant liquid level in the condenser.

As a result of replenishing the cooling jacket 2 with approximately 60% of the refrigerant in this way, an abnormal drop in the refrigerant liquid level is prevented, boiling cooling is continued, and overheating of the combustion chamber wall is prevented, and the inside of the cooling jacket 2 is prevented from overheating. Since the refrigerant temperature is lowered and the vapor pressure is lowered, the internal pressure of the system is lowered, and an increase in the boiling point of the refrigerant due to insufficient liquid phase refrigerant is suppressed, thereby preventing the occurrence of cavitation.

In carrying out the liquid level reduction control in the capacitor mentioned above, even if the liquid level in the capacitor 3 is lowered to the maximum, insufficient heat dissipation capacity cannot be avoided and the liquid level will reach the level set by the second liquid level sensor 34. If it has fallen, this is determined in step 367 in order to prevent the steam in the system from flowing into the reservoir tank 21, and in step S70 the second solenoid valve 17 is
is designated as the B flow path, and the control for lowering the refrigerant liquid level in the condenser 3 is canceled.

Furthermore, for the same reason, even when the liquid level in the condenser 3 is below the set level of the second liquid level sensor 34 in SIO of FIG. 3, the water level reduction control in the condenser 3 is not performed.

On the other hand, after the liquid level in the condenser 3 is appropriately controlled as described above, the amount of heat generated by the engine and the amount of heat dissipated from the condenser 3 are approximately balanced at their boiling point, and the system is sealed. Figure 3 3
The refrigerant temperature production control '4'B (FIG. 7) by fan control shown in S8 and the refrigerant temperature control based on liquid level control by the refrigerant circulation pump 4 (FIG. 8) shown in S8 are repeatedly performed.

(Refrigerant temperature control by fan control) In the fan control shown in Fig. 7, the system temperature can be controlled with even higher accuracy, specifically, "set temperature + 0.5°C (=α1)"
and “set temperature -0.5℃ (=α2)” (S52)
ON/OFF control of only the cooling fan 14 so as to maintain the cooling fan 14 (
S53. 554) Do.

(Liquid level control by pump control) In addition, in liquid level control, as shown in FIG. A liquid phase refrigerant is supplied to the cooling jacket 2, and the liquid level is maintained at a set level (S56.557).

If the liquid level inside cooling jacket 2 is below the set level,
As shown at 358, an abnormality check control for a drop in the liquid level in the cooling jacket 2 is performed. This has already been explained in FIG.

(Liquid level rise control in the capacitor) In addition, due to disturbances such as an increase in vehicle running wind or changes in the set temperature itself due to changes in operating conditions, the system internal temperature may be lowered to 39 lower limit temperature (first set temperature) T, = r setting Temperature -4.0℃ (=α
4), the liquid level increase control in the capacitor 3 according to the present invention shown in FIG. 11 is started. 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 3, thereby suppressing the heat dissipation ability. Specifically, when introducing the liquid phase refrigerant, a combination of refrigerant introduction using the pressure difference inside and outside the system (first control means) and forced introduction by driving the refrigerant circulation pump 4 in the opposite direction (second control means) are used. There is. That is, when the signal from the pressure sensor 35 indicates that the pressure inside the system is below 381P (substantially negative pressure), the control device 31
The third solenoid valve 24 is opened in S82 by the first control means of
The refrigerant is introduced using the pressure difference inside and outside the system. When this refrigerant is introduced, the detected temperature is "set temperature - 3.0"C (=α
k)' (S84.58
5) Finally, the inside of the system is sealed at 586 to complete the process.

The above-mentioned end temperature also takes into account the responsiveness of temperature change to the rise in the liquid level. If the liquid phase refrigerant in the cooling jacket 2 becomes insufficient during this refrigerant introduction, the refrigerant is replenished by the refrigerant circulation pump 4 in step 383. This was explained in FIG.

If the temperature in the system is 21 or more, or if it becomes 21 or more during the above-mentioned refrigerant introduction, the second control means of the control device 31 is activated and the process proceeds to S87 to close the third solenoid valve 24, The reservoir dunk 21 is driven in the reverse direction of the refrigerant circulation pump 4.
The liquid phase refrigerant is forcibly introduced into the condenser 3 (S89
．． 590). This forced introduction also continues until the detected temperature rises to "set temperature -3.0°C (-α,)" (384, 385).

Also, during this refrigerant introduction, the cooling jacket 2 is
If it is determined that there is a shortage of liquid phase refrigerant in the refrigerant, the second solenoid valve 17 is switched to flow path B and the refrigerant circulation pump 4 is driven in the forward direction to replenish the refrigerant (588, S91.5
92).

By the way, even if the flow from 381 to S85 is performed by the first control means, the refrigerant temperature decreases [set value -110'C (=
α7)] = If the temperature is lower than the second set temperature T2, the third solenoid valve 24 is opened and the differential pressure is used to cool the reservoir tank 21.
Even if the preliminary liquid phase refrigerant inside the capacitor is introduced into the condenser 3, the refrigerant liquid level in the condenser does not rise by the required amount, and it is determined that the amount of heat dissipated from the condenser 3 is superior and the refrigerant temperature has decreased. The cause of this is that Pl detected by the pressure sensor 35 is
The differential pressure between the capacitor 3 and the reservoir tank 21 is no longer sufficient due to a malfunction or the like.
The third solenoid valve 24 has failed or become clogged, and the passage area of the first auxiliary refrigerant passage 16 has been constricted or blocked, making it impossible to smoothly introduce the refrigerant. It is possible that there was a shortage. In such a case, the alarm 37 is activated in step 393 to issue an abnormality warning to urge discovery and repair of the malfunction, and at the same time, the second control means operates to activate the alarm 37 as described in steps 388 to 393.
392, the refrigerant circulation pump 4 is operated to forcibly replenish the reserve liquid phase refrigerant in the reservoir tank 21 to the condenser 3 via the second auxiliary refrigerant passage 23, thereby raising the refrigerant liquid level in the condenser 3. The heat radiation area of the capacitor 3 is reduced, the amount of heat radiation is reduced, and the refrigerant temperature is increased.

Note that the control of the refrigerant liquid level in the cylinder head is not a subject of the present invention.

As a result of the above liquid level rise control in the capacitor, the system temperature is S
At 85, [setting value - α4℃) = T, below [setting value - α6℃
] After being guided above, the process proceeds to 386, where the temperature control shown in FIG. 7 is performed using only the cooling fan 14 described above.

In this way, the liquid level inside the capacitor 3 is controlled at 89 so that the system temperature is always kept within the range of "set temperature +2.0°C" and "set temperature -4.0°C". For example, even if the set temperature changes significantly due to a sudden change in operating conditions, the heat dissipation capacity of the condenser 3 can be changed quickly and widely, and the resulting change in the amount of condensation immediately suppresses and promotes boiling of the refrigerant on the cooling jacket 2 side. Therefore, it is possible to follow the set temperature extremely well.

The cooling fan 14 is then controlled to further bring the temperature within the system within the set temperature range of ±0.5 cJ (S52), thereby achieving temperature control with even higher precision and better responsiveness. It is something that

Next, based on FIGS. 4 and 12, a description will be given of key-off control that is interrupted when the ignition key of the engine is turned off.

This is done by first setting the set temperature to 80°C at 3102 to perform the above-mentioned liquid level reduction control in the condenser 3,
In addition to making maximum use of the heat dissipation capacity of capacitor 3,
Cooling fan 14 for a maximum of 10 seconds set in 103
Forced cooling by driving (3103, 5104, 553)
L, the temperature inside the system becomes sufficiently low (e.g. 80°C) (SI
OI) or after a certain period of time (for example, 60 seconds) has passed (S106), the power is turned off (S10).
7). By turning off the power, the first solenoid valve 26, which is a normally closed solenoid valve, is closed, and the third solenoid valve 2, which is a normally open solenoid valve, is closed.
4 is open, liquid-phase refrigerant is naturally drawn from the reservoir tank 21 through the first auxiliary refrigerant passage 16 as the temperature in the system decreases, that is, the pressure decreases, and eventually the entire system becomes liquid. It will be filled with phase refrigerant and ready for the next start.

Furthermore, when introducing the liquid phase refrigerant, it flows into the system via the condenser 3, so even if a small amount of air enters for some reason during operation and adheres to the inside of the condenser tube, Reliable discharge to the upper part of the system is performed.

On the other hand, the ignition key may be turned on again during the key-off control described above, but in this case, the process proceeds to S18 to S21 based on the determination in S16 in FIG.
The cooling fan 14 and the set temperature are restored based on the information saved in step 5, and the program timers (5103 and 3106) are cleared in step 518 to return to the control state that was in progress before the key was turned off.

In the embodiment described above, the temperature of the refrigerant is controlled by detecting the actual refrigerant temperature using a temperature sensor and feeding it back. However, in the present invention, it is not necessarily a requirement to perform feedback control. It may be done as follows.

<Effects of the Invention> As described above, according to the present invention, a refrigerant circulation closed circuit is configured in the normal operating range and control is performed to increase the refrigerant liquid level in the condenser, so that the refrigerant temperature due to external disturbances such as changes in running air volume is reduced. It is possible to prevent the temperature from decreasing excessively and to quickly make the system temperature follow the set temperature.

In addition, the above-mentioned refrigerant liquid level raising control in the condenser uses both the introduction of the preliminary liquid phase refrigerant stored in the reservoir tank into the condenser by the differential pressure between the inside and outside of the system and the forced introduction by the auxiliary refrigerant supply means. While energy loss due to the operation of the auxiliary refrigerant supply means is reduced when differential pressure is used, if the amount of auxiliary refrigerant introduced by using the differential pressure inside and outside the system is insufficient or cannot be introduced for some reason, and the refrigerant temperature drops. Since the auxiliary refrigerant supply means is switched to replenish the auxiliary refrigerant, an excessive drop in refrigerant temperature can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing the basic configuration of the present invention in blocks;
FIG. 2 is a configuration explanatory diagram showing one embodiment of the present invention, and FIGS.
FIG. 12 is a flowchart showing the details of control in this embodiment. 1... Internal combustion engine 2. A...cooling jacket 3,
C... Condenser 4... Refrigerant circulation pump 14.
8... Cooling fan 15... Refrigerant circulation passage 16,
G...First auxiliary refrigerant passage B 17...Second solenoid valve (Solenoid valve F) 21. E...Reservoir tank 23
, ■... Second auxiliary refrigerant passage 24... Third solenoid valve 31... Control device 33... Temperature sensor (temperature detection means K) 35... Pressure sensor (pressure detection means J) 3
7...Alarm device D...Liquid phase refrigerant circulation means H.
...Auxiliary refrigerant supply means L...Liquid level rise control means in the condenser L,...First control means L2...
Second control means patent applicant: Nissan Motor Co., Ltd. Agent Patent attorney Fujio SasashimaFigure 6Figure 7Figure 8

Claims (1)

[Claims] A cooling jacket for an internal combustion engine in which a liquid-phase refrigerant is stored, a condenser in which a gas-phase refrigerant is condensed and the condensed liquid-phase refrigerant is stored in the lower part, and a liquid-phase refrigerant circulation means. It is equipped with a refrigerant circulation closed circuit that radiates the latent heat of the vapor phase refrigerant absorbed and evaporated in the condenser, and
a reservoir tank provided outside the refrigerant circulation closed circuit and storing a preliminary liquid phase refrigerant; a first auxiliary refrigerant passage communicating the reservoir tank and the lower part of the condenser via a solenoid valve; and the reservoir tank and the condenser. a second auxiliary refrigerant passage communicating with the lower part via an auxiliary refrigerant supply means, and a pressure detection means for detecting the pressure within the refrigerant circulation closed circuit;
Temperature detection means for detecting the liquid phase refrigerant temperature in the refrigerant circulation closed circuit, and a capacitor that selectively operates the electromagnetic valve and the auxiliary refrigerant supply means when the temperature detection means detects a first set temperature T_1 or lower. an internal liquid level rise control means, the condenser internal liquid level rise control means operates the solenoid valve when the temperature condition is satisfied and the pressure detection means detects a pressure below a predetermined value P_1. The first control means for opening the valve and the pressure detection means operate at a predetermined value P_
1 or more positive pressure is detected, the pressure detection means detects a pressure below a predetermined value P_1, and the temperature detection means detects a second set temperature T_2 or lower which is lower than the first set temperature T_1. A refrigerant temperature control device in an evaporative cooling device for an internal combustion engine, comprising: a second control device that sometimes operates the auxiliary refrigerant supply device.