JPS6183416A - Evaporative cooling apparatus of internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve thermal load by returning the liquid coolant supplied from a condenser into a cooling jacket through the vicinity of the seat part of an exhaust valve, thus effectively cooling the exhaust-valve seat part. CONSTITUTION:A coolant feeding hole 52 is formed in close to a valve seat 55 for an exhaust valve and a valve seat 58 for a suction valve, between these valvees installed onto a cylinder head 3. The feeding hole 52 communicates to a coolant gallery 50, and the coolant cooled by a condenser forms liquid phase and is returned into a cooling jacket 5 in the vicinity of the valve seats 55 and 58 of an exhaust valve 54 and a suction valve 57. Therefore, the vicinity of the valve seat is effectively cooled, and thermal load is improved.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention cools the engine by boiling and vaporizing a liquid phase refrigerant that is circulated and supplied from an external condenser into the water jacket of the engine. The present invention relates to a boiling cooling device for an internal combustion engine.

<Prior art> As a cooling device for an internal combustion engine, an extremely efficient boiling cooling device that utilizes the boiling and condensing cycle of a refrigerant (cooling water) has been developed, for example, in place of the conventional water-cooled cooling device.
-57608, etc., and the present applicant has already filed various applications (for example, Utility Model Application No. 57-996).
No. 67, Japanese Patent Application No. 145470, etc.). This basically goes to the cylinder block and cylinder.
The liquid phase refrigerant is stored up to a predetermined level in the water jacket formed over seven steps, and each part is cooled by boiling vaporization of this liquid phase refrigerant, and the generated steam is taken out from the upper part of the walk jacket. The water is introduced into a condenser, where it is condensed and liquefied, and then circulated and supplied into the water jacket again.

<Problems to be Solved by the Invention> Incidentally, in an internal combustion engine, it goes without saying that it is necessary to concentrate cooling around the exhaust valve seat, which has a high heat load, but when the above-mentioned boiling cooling method is applied, Due to the conditions, cooling this part becomes a difficult issue.

In other words, whether or not the cooling effect is good in the boiling cooling method described above depends largely on whether or not heat is transferred to and received from the liquid phase refrigerant.
In this type of system in which liquid refrigerant is stored in a water jacket, the vapor generated from the stored liquid refrigerant turns into bubbles and floats up through the liquid refrigerant. Existence ratio of air bubbles contained in phase refrigerant (bubble ratio)
Considering this, the bubble rate is very high on the cylinder head side, so the transfer of heat to the liquid phase refrigerant on the cylinder head side is likely to be hindered by the bubbles. Moreover, the exhaust valve seat part is
The water jacket has a relatively complex shape due to the exhaust boat and the intake port adjacent to it, and is small in volume, so the generated steam is not quickly exhausted and tends to accumulate, which increases the transfer of heat. The result is that the

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to further expand the advantages of the evaporative cooling device by enabling intensive cooling of the area around the exhaust valve seat of the cylinder head.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides each cylinder with a refrigerant supply hole that communicates with the water jacket near the exhaust valve seat of the cylinder head, so that the refrigerant supply hole is connected to the water jacket near the exhaust valve seat of the cylinder head. At least a portion of the liquid phase refrigerant that is circulated and supplied into the water jacket is introduced through the refrigerant supply hole.

In other words, part or all of the liquid phase refrigerant from the condenser is supplied to the water jacket near the exhaust valve seat of the cylinder head through the refrigerant supply hole provided for each cylinder. A new liquid refrigerant that does not contain bubbles is always supplied near the seat to efficiently remove heat.

At the same time, this new supply of liquid refrigerant also actively stirs the liquid refrigerant that exists near the exhaust valve seat, which prevents air bubbles from adhering to the walls and forms a relatively complex shape. Air bubbles are encouraged to escape from this area,
Air bubbles are prevented from accumulating. Therefore, local overheating near the exhaust valve seat can be prevented, and the heat load can be improved.

<Example> The present invention will be explained in detail below.

1 to 5 show one embodiment of the cylinder head for the evaporative cooling device according to the present invention, and FIG. 6 shows another embodiment. The overall configuration will be explained.

In FIG. 7, 1 indicates a diesel engine, and a water jacket 4.5 is formed in a cylinder block 2 and a cylinder head 3, respectively.

The water jacket 4.5 is formed on the cylinder block 2 and cylinder head 3 so as to surround the outer periphery of the cylinder and combustion chamber of the engine 1, and includes a water jacket 4 on the cylinder block side and a water jacket 5 on the cylinder head side. communicate with each other via a plurality of communication holes 6, and are substantially integrated. In the upper part of the water jacket 5 on the cylinder head side, which becomes the gas phase space,
A plurality of steam ratio lowers are formed. These steam ratio lowers are connected to a steam passage 9 via a steam manifold 8, and the steam manifold 8 has a discharge pipe attachment part 10 which is the top of the refrigerant circulation system and stands upward. The camp 11 seals the upper end opening.

Reference numeral 12 denotes a condenser that condenses and liquefies a vapor phase refrigerant, and includes an upper tank 13 to which the vapor passage 9 is connected, a core section 14 mainly consisting of fine vertical tubes, and a liquefied refrigerant condensed in this core section 14. It is constructed from a lower tank 15 that temporarily stores water, and is installed in a position that receives wind from the vehicle, such as at the front of the vehicle. Further, an electric cooling fan 16 for forced cooling is provided on the front or back side. Further, the lower tank 15 has one end connected to a refrigerant circulation passage 17 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 17 is connected to the cylinder head side water jacket 5, and a second solenoid valve 31, which will be described later, and an electric refrigerant supply pump 18 are interposed in the middle part. There is.

A refrigerant circulation system is constituted by the above water jacket 4.5 = steam passage 9 - condenser 12 -> lower tank 15 -> second solenoid valve 31 -> refrigerant supply pump 18, and during normal operation, for example, water enters the circulation system. The refrigerant with some additives is circulated while repeatedly boiling and condensing.

Here, the structure of the part that returns the liquid phase refrigerant from the refrigerant supply pump 18 to the water jacket 5 of the cylinder head 3 will be explained as follows.
To explain in detail with reference to FIGS. 5 to 5, a gear rally 50 is formed on the lower side wall of the cylinder head 3 and extends in the direction in which the cylinders are arranged side by side. As shown in FIG. 5, they are connected via a connector 51. And Gallery 5
A refrigerant supply hole 52 is formed for each cylinder from zero. 5
3 is a blind plug.

The refrigerant supply hole 52 extends obliquely upward to the inside of the position where the communication hole 6 that communicates the cylinder block side water jacket 4 and the cylinder head side water jacket 5 is provided. It opens between the wall of the exhaust boat 56 around the seat 55 and the wall of the intake port 59 around the intake valve seat 58 of the intake valve 57 .

Alternatively, as shown in FIG. 6, the exhaust valve 54 may be opened toward the wall of the exhaust boat 56 around the exhaust valve seat 55. Note that 60 indicates a sub-combustion chamber.

Next, returning to FIG. 7, reference numeral 25 indicates a reservoir tank, which is provided outside the circulation system to store a preliminary liquid phase refrigerant, and is equipped with a cap 26 having a ventilation function. is open to the atmosphere through
It is installed at a relatively high location in the vehicle so as to ensure a liquid level at the uppermost end of the circulation system, that is, at a higher position than the exhaust pipe attachment portion 10 of the steam manifold 8. The exhaust pipe attachment part 10 includes an air exhaust passage 2 for exhausting air inside the system.
7 is connected to the reservoir tank 25, and in order to recover the liquid phase refrigerant that overflows at the same time as the air is discharged, the tip of the air discharge passage 27 is inserted into the reservoir tank 25, and is opened at a relatively upper portion thereof. . 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 refrigerant supply pump 18 of the refrigerant circulation passage 17 through the second solenoid valve 31, which is a three-way valve.
Connected to the upstream side (intake side).

When the second solenoid valve 31 is not energized, the refrigerant circulation passage 17
Flow path A) in which the first auxiliary refrigerant passage 29 and the refrigerant supply pump 18 are communicated with each other by blocking the energization, and a flow path B in which the first auxiliary refrigerant passage 29 is interrupted and the refrigerant circulation passage 17 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 15 as described above, and a normally open third solenoid valve 32 is interposed in the middle thereof.

Each of the above solenoid valves 2B, 31.32, refrigerant supply pump 18
The cooling fan 14 is driven and controlled by a control device 33 using a microcomputer, and specifically, a first liquid level sensor 34 provided on the cylinder head side water jacket 5. Temperature sensor 35. A second liquid level sensor 36 provided in the lower tank 15. 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.

Above 1. The second liquid level sensor 34, 36 is a float type sensor using a refrigerant, for example, and detects whether the refrigerant liquid level has reached a set level in an on/off manner. The first liquid level sensor 34 has its detection level set at a height approximately in the middle of the cylinder head 3, 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 at a height of . 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 where it is normally immersed in the liquid phase refrigerant.
The temperature of the refrigerant inside the water jacket 5 is detected. 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. Specifically, it detects whether the
The working pressure was set to about 0 mmHg.

To explain the basic cooling mechanism of the boiling cooling device configured as above, the water jackets 4, 5
The liquid phase refrigerant is stored in the tank up to a predetermined level, that is, the level set by the first liquid level sensor 34, and when this liquid phase refrigerant is heated by the combustion heat of the engine, the current in the system changes. Boiling begins when the boiling point corresponding to the pressure is reached, and the latent heat of vaporization is taken away, resulting in evaporation. 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 effective cooling.

The refrigerant vapor generated within the water jackets 4 and 5 is led to the condenser 12 via the vapor passage 9, where it is cooled by heat exchange with outside air and condensed into liquid. In this condenser 12, good heat exchange is performed between the high-temperature steam and the outside air, and the heat dissipation efficiency is much better than that of a radiator of a normal water-cooled cooling device. The liquefied refrigerant is temporarily stored in the lower tank 15 at the bottom of the condenser 12, and from there, the refrigerant supply pump 18 feeds the water jackets 4 and 5 again to keep the liquid level in the water jackets 4 and 5 above a predetermined level.
It is circulated and supplied to

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.

Here, the liquefied refrigerant from the condenser 12 flows into the water jacket section between the exhaust valve seat 55 and the intake valve seat 58 via the refrigerant supply hole 52 provided for each cylinder by the refrigerant supply pump 18.

In other words, new liquid phase refrigerant that does not contain bubbles is always supplied to this water jacket section.
Heat can be efficiently removed from the vicinity of the exhaust valve seat 55, which has a large heat load. On the other hand, the inflow of the liquid refrigerant from the refrigerant supply hole 52 described above also actively stirs the liquid refrigerant present in the vicinity of the exhaust valve seat 55, thereby preventing air bubbles from adhering to the wall surface. At the same time, the discharge of air bubbles from this portion, which has a relatively complicated shape, is promoted, and the accumulation of air bubbles is prevented. Therefore, heat transfer from the wall surface around the exhaust valve seat 55 to the liquid refrigerant is improved, and
The steam generated as a result of this exchange of heat is quickly discharged to the outside, so that heat transfer becomes extremely smooth and local overheating in the vicinity of the exhaust valve seat 55 can be prevented.

In this example, the reason why the refrigerant supply hole 52 is directed toward the water jacket section between the exhaust valve seat 55 and the intake valve seat 58 is because this section is directed toward the adjacent intake/exhaust port 5.
This is because it is narrowed by the wall surface of 6.59 and vapor tends to accumulate therein, but the liquid phase refrigerant may be supplied directly around the exhaust valve seat 55 as shown in FIG. When one cylinder has two exhaust valves, the liquid phase refrigerant may be supplied to the water jacket between the two exhaust valve seats.

In addition, the refrigerant supply hole 52 is oriented slightly upward at an angle so that steam and air can escape.Moreover, when the refrigerant is supplied from the refrigerant supply hole 52, the refrigerant is passed from the cylinder block side water jacket 4 to the communication hole 6 into the cylinder. The refrigerant supply hole 5 is connected to the head side water jacket 5 so as not to be disturbed by the cool air flow jetting out as shown by the arrow F in FIG. 4.
2 is opened inside the communication hole 6. however,
Make the refrigerant supply hole 52 longer than necessary (if this happens, it will turn into steam in the middle), so make sure to make the refrigerant supply hole 52 longer than necessary, so that it is on the outside diameter of the bore or beyond it, and avoid providing passages in locations with high heat loads. There is.

Furthermore, it is not necessarily necessary to supply the entire amount of the circulating refrigerant from the refrigerant supply hole 52; for example, a portion may be introduced from the lower part of the cylinder block side water jacket 4.

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 12 by introducing preliminary liquid phase refrigerant into the system, and after that, when the temperature recovers, excess refrigerant is also 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 the time control, an excessive amount of refrigerant is detected and the above-mentioned surplus refrigerant is transferred to the reservoir tank 25.
I did the operation of returning to 1 again, and the operation was 1 with excessive amount of refrigerant! This is to avoid being continued.

Next, specific control executed by the control device 33 will be explained based on flowcharts shown in FIGS. 8 to 16.

FIG. 8 is a flowchart showing the outline of the control. When the control is started by starting the engine (engine key ON), a predetermined initialization process (step 1) is performed, and then the start is determined to be an initial start. Is it a restart?
Specifically, the temperature detected by the temperature sensor 35 is the set temperature (
(e.g. 45℃) (Step 2)
). If the initial startup is below the set temperature, that is, in an unwarmed state, the process goes through air discharge control (step 3) and then surplus refrigerant discharge control (step 4), and then normal operation control (step 5 and negative pressure prevention control). Repeat step 6) until the key is turned off.On the other hand, if the temperature is higher than the set temperature in step 2, that is, when restarting, air may have entered over time.
Therefore, 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. 9 is executed, and the key OF
After a certain process by the F control (step 7), the power is turned off and the series of controls ends.

FIG. 10 shows a flowchart of air discharge control in step 3. First, in step 11, the first solenoid valve 28 is opened, the second solenoid valve 31 is turned off (flow path A), and the third solenoid valve 31 is turned off.
2 and then turn on the refrigerant supply pump 1 (Step 7, Step 12). As a result, reservoir tank 2
The preliminary liquid phase refrigerant in 5 is introduced into the circulation system via the first auxiliary refrigerant passage 29. This is continued for a predetermined period of time determined by a software timer T 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 reservoir tank 25 side via the air discharge passage 27.

Also, when the air in the system runs out, 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 18 is turned off (step 14). That is, at this point, air has been completely exhausted from the circulation system.

Figures 11 and 12 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.

This basically uses the vapor pressure generated by the start of boiling within the water jackets 4 and 5 to push out excess liquid phase refrigerant to the reservoir tank 25 outside the system.
At this time, if the liquid level in the lower tank 15 drops to the set level first due to various conditions (this is usually the case at cold start), or if the liquid level in the water jacket 5 on the cylinder head side drops to the set level first. (
If the liquid level in the lower tank 15 drops first, the procedure shown in Figure 11 will be followed, or if the liquid level in the water jacket 5 drops first. 12. First, in step 21 of FIG. 11, the first solenoid valve 2 is
8 is closed, the second 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 to monitor the liquid level in the lower tank 15 and the liquid level in the water jacket 5.

If the liquid level in the lower tank 15 first drops to the set level due to the 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 manually set the target temperature using 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 non-king occurs at around 110 degrees Celsius. In the high load range where it is easy to do so, the temperature is set to about 100°C.

In this state, in step 29, the water jacket 5
The excess liquid refrigerant in the water jackets 4 and 5 is moved to the lower tank 15 in the form of [boiling in the water jackets 4.5 → WE contraction in the condenser 12]. When the liquid level in the lower tank 15 rises above the set level, the third solenoid valve 32 is opened (step 32) while the cooling fan 16 is turned off (step 31) based on the determination in step 22. Excess liquid phase refrigerant is discharged to the reservoir tank 25, and when the liquid level in the lower tank 15 decreases, the third
The solenoid valve 32 is closed (step 24). That is, by repeatedly opening and closing the third solenoid valve 32, excess liquid phase refrigerant is gradually discharged out of the system, and after that, when the liquid level in the water jacket 5 has decreased to the set level, as shown in FIG. Proceed to step 33. 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), the third solenoid valve 32 is opened (step 32), and liquid phase refrigerant is introduced from the reservoir tank 25 to restore the system pressure to approximately atmospheric pressure and prevent the engine from overheating. Prevent cold.

Further, 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 15 is above the set level at that point. Therefore, step 34 to step 36
While controlling the liquid level in the water jacket 5, the liquid level in the lower tank 15 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 5 and lower tank 15, and the remaining part is in the gas phase. The refrigerant is leaking.

On the other hand, if the liquid level in the water jacket 5 drops first, the determination in step 29 causes the liquid level to drop in step 30.33.
The process then proceeds to step 34. Thereafter, steps 34 to 37 are repeated with the third electromagnetic valve 32 kept open to monitor the liquid level in the lower tank 15 while controlling the liquid level in the water jacket 5 to the set level. and,
Similarly, when the liquid level in the lower tank 15 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 the need for temperature control by the cooling fan 16.

Next, FIGS. 13 and 14 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 jackets 4 and 5 side and the amount of liquid phase refrigerant on the lower tank 15 side, and the amount of refrigerant sealed in the system. It consists of refrigerant excess avoidance control and refrigerant shortage avoidance control that detect excess or deficiency of refrigerant and discharge or replenish it.

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 16 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 promotion or suppression of condensation due to the presence or absence of air blowing changes the pressure within the system and slightly affects the boiling point of the refrigerant in the water jacket 4.5, so the engine temperature can be controlled with extremely high responsiveness. Can be controlled with high precision.

On the other hand, liquid level control is processed by steps starting from step 45. This gives priority consideration to maintaining the liquid level in the water jacket 5 at a set level, and only under certain conditions, allows the liquid level in the water jacket 5 to rise above the set level, and The liquid level is also controlled. Specifically, if it is determined in step 45 that the liquid level in the water jacket 5 is below the set level, the refrigerant supply pump 18 is turned on (step 4
7), and the liquid phase refrigerant is circulated and supplied from the lower tank 15 to the water jacket 5. The supply of the liquid phase refrigerant is continued at least until it is determined in step 45 that the liquid level in the walk jacket 5 has reached the set level.

If the hot water temperature in the system substantially matches the target value when the set level is reached (step 50), the refrigerant supply pump 18 is immediately turned off without considering the liquid level in the lower tank 15.
Step 54). However, if the system temperature is 1.5°C or more higher than the target value in step 50, the refrigerant supply pump 18 is operated in steps 51 -> step 52 -> step 47 until the liquid level in the lower tank 15 falls to the set level. (at the same time, the water jacket 5
(The liquid level inside will be above the set level). This is because even if the liquid level in the water jacket 5 is kept constant, if the boiling state changes and the proportion of vapor bubbles in the liquid phase refrigerant in the water jacket 4.5 increases, the lower tank 15
The liquid level on the capacitor 12 side may become high and reach the capacitor core part 14, reducing the effective heat dissipation area. This increases 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, in order to expand the heat radiation area of the capacitor 12, the stellar 15
10, the refrigerant supply pump 18 is driven by controlling the liquid level in the lower tank 15. In step 52, the software timer T2 monitors the duration of m consecutive openings of the pump in the ON state. When the amount is above, it is determined that the amount of refrigerant enclosed is excessive.

That is, when only the liquid level on the water jacket 5 side is controlled, all the excess liquid phase refrigerant in the case of excess refrigerant is unevenly distributed on the lower tank 15 side, and this is transferred to the water by driving the refrigerant supply pump 18. jacket 4.5
Since the refrigerant must be moved to the side, if the refrigerant takes an excessively long time to move, the amount of refrigerant sealed in the refrigerant is excessive. If it is determined that the amount is excessive, the refrigerant supply pump 18. After stopping the cooling fan 16 and clearing the software timer T2, the process again proceeds to the above-mentioned surplus refrigerant discharge control (FIG. 11). 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 phase refrigerant flows into the condenser 12 from the water jacket 5 together with steam and reduce the heat radiation efficiency, resulting in poor cooling and cooling fan 16. This can prevent an increase in driving frequency.

Furthermore, 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 capacitor 12 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. The reason why the enclosed refrigerant becomes excessive is that when the refrigerant circulation system is sealed by the third solenoid valve 32 in the surplus refrigerant discharge control (step 4) described above and the negative pressure prevention control (step 6) described later, 1. This is caused by the second liquid level sensors 34, 36 malfunctioning due to vibrations, etc., or by the liquid phase refrigerant being biased 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 performed in step 4 when the liquid level in the water jacket 5 falls below the set level in the liquid level control described above.
The refrigerant supply pump 18 is turned ON based on the determination in step 5. At this time, the software timer T3 monitors the duration of the state below the set level in step 46, and if this is longer than the set time, for example, 10 seconds, the refrigerant supply pump 18 is turned on. It is determined that the amount of refrigerant enclosed is too small and the second solenoid valve 31 is turned off.
F (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 is appropriate, and the amount of refrigerant is If you are satisfied, you will never exceed this.

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

When the second solenoid valve 31 is set to the flow path A as described above, the refrigerant supply pump 18 is simultaneously turned on (step 47
), the preliminary liquid phase refrigerant in the reservoir tank 25 is forcibly replenished into the system. This continues until the liquid level in the water jacket 5 reaches the set level. When the set level is reached, turn Stereo knob 48. At step 49, replenishment is stopped and the software timer T3 at 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 5 to the water jackets 4 and 5, there is no possibility that the combustion chamber wall will be exposed due to insufficient amount of refrigerant.

Next, FIG. 15 shows a flowchart of the negative pressure prevention control (step 6) performed following the above-mentioned normal operation control (step 5). This is to prevent supercooling caused by boiling under reduced pressure when the wind is too strong when the vehicle is running, and the temperature inside the system is 97°C or less (step 61) and the temperature inside the system is actually lower than the outside pressure. This is performed on the condition that the pressure is negative (step 62). However, under pressure conditions only,
If the boiling point of the refrigerant at atmospheric pressure is 100"C or higher (such as when antifreeze is added to water), it will be impossible to control the temperature around 100"C while the system is sealed, and the temperature will change depending on the temperature condition. In this case, there is a risk that steam may 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, the liquid phase refrigerant is introduced from the reservoir tank 25 into the system which is under negative pressure, and as a result, the pressure in the system is restored to approximately atmospheric pressure, and as a result, the water jacket 4
．． The boiling point of the liquid phase refrigerant in 5 increases. Also, step 6
4 to Step 66, the liquid level in the water jacket 5 continues to be controlled at the set level, so the reservoir tank 25
Only the liquid level of the condenser 12 becomes high due to the liquid phase refrigerant flowing in from the condenser 12. Therefore, the heat dissipation amount of the capacitor 12 decreases, and the capacitor 12
The liquid level inside will fluctuate up and down.

The system open state described above is continued until the system becomes positive pressure (step 67) and the liquid level in the lower tank 15 drops 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 an increase in vapor pressure, and the liquid level in the lower tank 15 drops to the set level. At this point, the third solenoid valve 32 is closed (step 69).
), this negative pressure prevention control ends. As a result, the refrigerant circulation system is again sealed with a predetermined amount of refrigerant, and the above-mentioned normal operation control (FIG. 13) 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. 16 shows key OFF control (step 7) that is interrupted when the engine key of the engine is turned OFF.

First, by the temperature judgment in step 74, if the temperature inside the system is relatively low (for example, 75°C or less), the power is immediately turned off.
F (step 83), but if the temperature is higher than this, the cooling fan 16 is driven for a maximum of 10 seconds by setting the software timer T4 to force cooling (step 76).
- Step 78) and waits until the inside of the system cools down to negative pressure (Step 82).

Also, during this period, control of the liquid level in the water jacket 5 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. By turning off the power, the first solenoid valve 28, which is a normally closed type, is closed, the second solenoid valve 31 is connected to the flow path A, and the third solenoid valve 32, which is a normally open type, is opened, so that the temperature in the system decreases. In other words, as the pressure decreases, preliminary liquid refrigerant is introduced from the reservoir tank 25 through the second auxiliary refrigerant passage 30, and eventually the entire system is filled with liquid refrigerant in preparation for the next startup. It turns out. In addition, when the above-mentioned preliminary liquid phase refrigerant is introduced, it flows into the system from the lower tank 15 via the core section 14, so a small amount of air may enter the fine 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, during the above key OFF control, the engine key is turned OFF again.
N operation may be performed, but in this case step 73
Based on this determination, the process proceeds to step 84, and based on the information saved in advance (step 71), the control state that was in progress before the key was turned off is restored.

In this embodiment, the refrigerant circulation system consisting of the water jacket 4.5, the condenser 12, the refrigerant supply pump 18, etc. is a closed circulation system during normal operation. That is,
A reservoir tank 25 provided outside the circulation system and storing a preliminary liquid phase refrigerant; a refrigerant introducing means for introducing liquid phase refrigerant for air discharge from the reservoir tank 25 into the circulation system; 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;
In addition, by providing an air exhaust passage that is opened when the refrigerant is introduced and closed when it is discharged, air, which is a non-condensable gas, can be reliably removed from the circulation system, thereby creating a closed circulation system. The goal is to achieve this goal and improve the reliability and stability of cooling performance. However, the system configuration of the closed circulation system is not limited to this, and may be, for example, the configuration shown in Japanese Patent Application No. 58-228145 or Japanese Patent Application No. 59-140378.

<Effects of the Invention> As explained above, according to the present invention, at least a part of the liquid phase refrigerant that is circulated and supplied from the condenser to the water jacket of the engine is supplied to the cylinder head side through the refrigerant supply hole provided for each cylinder. Since the water jacket is extended to the vicinity of the exhaust valve seat, the area around the exhaust valve seat can be effectively cooled and the heat load can be improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a cylinder head for an evaporative cooling device showing one embodiment of the present invention, Fig. 2 is a bottom view of the same as above, Fig. 3 is an enlarged sectional view of the FIG. 5 is an enlarged sectional view of the main parts of the same, FIG. 6 is a plan sectional view of a cylinder head showing another embodiment, FIG. 7 is a configuration diagram of the boiling cooling device, and FIG.
Figures 1 to 16 are flowcharts showing control details. 1... Engine 2... Cylinder block 3...
・Cylinder head 4.5...Walk jacket 6...Communication hole 7...Steam outlet 9...Steam passage 12...Condenser 14...Lower tank
16...Cooling fan 17...Refrigerant circulation passage
18... Refrigerant supply pump 25... Reservoir tank 2B, 31.32... Solenoid valve 33...
-Control device 50... Gear rally 52... Refrigerant supply hole 54... Exhaust valve 55... Exhaust valve seat 56... Exhaust port 57... Intake valve 58
... Intake valve seat 59 ... Intake boat patent applicant Nissan Motor Co., Ltd. agent Patent attorney Fujio Sasashima Figure 8 Figure 9 Figure 10 Figure 12

Claims (4)

[Claims] (1) An engine water jacket that is formed across the cylinder block and cylinder head, stores liquid phase refrigerant, and has a steam outlet at the top of the cylinder head, and a condenser that condenses and liquefies the steam from the steam outlet. , in a boiling cooling device for an internal combustion engine, in which liquid-phase refrigerant is circulated and supplied from the condenser to the water jacket, a refrigerant supply hole communicating with the water jacket portion near the exhaust valve seat of the cylinder head is provided for each cylinder; A boiling cooling device for an internal combustion engine, characterized in that at least a part of the liquid phase refrigerant that is circulated and supplied from the condenser to the water jacket is introduced through the refrigerant supply hole. (2) The evaporative cooling device for an internal combustion engine according to claim 1, wherein the refrigerant supply hole opens toward a portion at an intermediate position between the exhaust valve seat and the intake valve seat. (3) The evaporative cooling device for an internal combustion engine according to claim 1 or 2, wherein the refrigerant supply hole is formed diagonally upward in the refrigerant supply direction. (4) Claims 1 to 3, characterized in that the refrigerant supply hole opens at a position inside the communication hole between the cylinder block side water jacket and the cylinder head side water jacket. The evaporative cooling device for an internal combustion engine according to any one of the above.