JPH0692731B2 - Boiling cooling device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention stores a liquid-phase refrigerant to a predetermined level in a water jacket, cools each part of an internal combustion engine by evaporating the liquid-phase refrigerant, and cools the generated refrigerant vapor. The present invention relates to a boiling cooling device for an internal combustion engine, which is condensed by a condenser and reused.

2. Description of the Related Art As a cooling device for an internal combustion engine, a boiling cooling device utilizing a boiling / condensing cycle of a refrigerant (cooling water) has been proposed in Japanese Patent Publication No. 57-57608, etc., in place of the conventional water cooling type cooling device. However, the applicant of the present invention has already developed various applications (for example, Japanese Patent Application No. 58-145470, Japanese Patent Application No. 58-228146, and Japanese Patent Application No. 59-10) which can be sufficiently put to practical use.
No. 0156 etc.) This consists of a water jacket in which the liquid-phase refrigerant is stored to a predetermined level, a condenser connected to the steam outlet in the upper part of the water jacket via a steam passage, and a condenser jacket in which the liquefied refrigerant is temporarily stored from the water jacket. A refrigerant supply pump that circulates the liquid-phase refrigerant as a main component, and is a configuration that forms a closed refrigerant circulation system, for example, at the time of start-up, the liquid-phase refrigerant between the reservoir tank outside the system and the inside of the refrigerant circulation system. While the air that is non-condensable gas is discharged by moving it, while the engine is operating, the coolant level in the water jacket is monitored by the level sensor to control the coolant supply pump and control the level of the coolant to a predetermined level. It is something that is maintained. According to the boiling cooling device that utilizes the latent heat accompanying the phase change of the refrigerant, the heat exchange efficiency can be dramatically improved, and each part can be uniformly cooled to the boiling point of the refrigerant.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention By the way, as a refrigerant in a boiling cooling apparatus of this kind, in view of easiness of handling, magnitude of latent heat of vaporization, price, etc., water is mixed with ethylene glycol or the like as an antifreeze liquid, and It has been considered to use a material to which a slight amount of a rust-preventing agent is added. However, for example, the aqueous solution of ethylene glycol is a non-azeotropic mixture, so the vapor of the aqueous solution contains almost no ethylene glycol, and only steam is present. Becomes For example, the vapor of a 50% (wt%) aqueous solution of ethylene glycol contains only about 2% ethylene glycol.

Therefore, when the above-mentioned boiling cooling device is continuously operated, a large amount of ethylene glycol is unevenly distributed in the water jacket, and the ethylene glycol concentration becomes very small on the condenser side. Therefore, in the winter, there is a possibility that the capacitor freezes inside and damages the capacitor, or the solenoid valve and the refrigerant supply pump freeze and malfunction occurs.

In the boiling cooling device, after the engine is stopped, the liquid-phase refrigerant is moved from the reservoir tank into the refrigerant circulation system to finally maintain a substantially full state. Since the movement of the engine between the lower tank and the lower tank of the condenser is repeated during the normal operation of the engine, the ethylene glycol concentration becomes very thin when the operation is continued for a long time. . Therefore, even if the liquid-phase refrigerant in the reservoir tank having a reduced ethylene glycol concentration is introduced to the condenser side after the engine is stopped, the uneven distribution of ethylene glycol during the engine stop cannot be prevented. In particular, in the refrigerant circulation passage that sends the liquid-phase refrigerant from the condenser to the water jacket, the refrigerant supply pump has a large passage resistance, and therefore, when the liquid-phase refrigerant moves from the reservoir tank side into the system after the engine is stopped, most of it is Passes through the condenser side, and the liquid-phase refrigerant in the refrigerant circulation passage (again, the ethylene glycol concentration is thin) does not move much, so that the liquid-phase refrigerant with a low ethylene glycol concentration is in the refrigerant circulation passage or pump. And remains frozen, and freezes easily occur while the engine is stopped. In addition, since the condenser tube is also thin, once the liquid-phase refrigerant moves from the reservoir tank and becomes full, rapid diffusion of ethylene glycol cannot be expected at all. Freezing and damage may occur before the uneven distribution is resolved.

Also, not only after the engine is stopped, but in the operation in cold regions where freezing becomes a problem, the refrigerant circulation amount decreases and the liquid level in the condenser is controlled to a high level to prevent overcooling. The liquid-phase refrigerant stays on the condenser side for a long time. Therefore, if the condenser is installed away from the engine, the temperature of the refrigerant at the condenser outlet may be considerably low. However, freezing can occur near the condenser outlet.

Means for Solving the Problems The present invention is provided with a heater pump for circulating the liquid phase refrigerant in the water jacket to the heater core for heating the passenger compartment in order to prevent uneven distribution of the antifreeze component in the refrigerant as described above. In the above, the refrigerant mixing passage is branched from the heater refrigerant passage on the discharge side of the heater pump, and the tip thereof is connected to the inlet side of the condenser.

Function The heater pump is driven when heating is required in conjunction with the heater switch, but in situations where freezing of the refrigerant occurs, heating is always required when the engine is operating.
The heater pump is driven. By driving the heater pump, the liquid-phase refrigerant in the water jacket flows through the heater core. Then, a part of the liquid phase refrigerant is branched from the heater refrigerant passage, flows into the refrigerant mixing passage, and is sent to the condenser. This suppresses the decrease in the concentration of the antifreeze component on the condenser side.

Embodiment FIG. 1 shows an embodiment of the boiling cooling apparatus according to the present invention, in which 1 is an internal combustion engine equipped with a water jacket 2, 3 is a condenser for condensing a vapor phase refrigerant, and 4 is a condenser. Each of the electric refrigerant supply pumps is shown.

The water jacket 2 is formed over both the cylinder block 5 and the cylinder head 6 so as to surround the cylinder of the internal combustion engine 1 and the outer peripheral portion of the combustion chamber. And the steam outlet 7 is provided at an appropriate position on the upper part thereof. The steam outlet 7 communicates with an upper inlet 3a of the condenser 3 via a connecting pipe 8 and a steam passage 9, and the connecting pipe 8 has a discharge pipe mounting portion 8a which is the uppermost part of the refrigerant circulation system. It is formed so as to rise upward, and a cap 10 seals the upper opening thereof.

The condenser 3 is an upper tank having the inlet 3a.
11, a core portion 12 mainly composed of a fine tube along the up-down direction, and a lower tank 13 for temporarily storing the liquefied refrigerant condensed in the core portion 12, for example, a vehicle such as a vehicle front portion. It is installed at a position where it can receive the running wind, and is equipped with an electric cooling fan 14 for forced cooling on its front or back surface. The lower tank 13 has one end of a refrigerant circulation passage 15 connected to a relatively lower portion thereof and one end of a first auxiliary refrigerant passage 16 connected to an upper portion thereof. The other end of the refrigerant circulation passage 15 is connected to a refrigerant inlet 2a provided on the cylinder head 6 side of the water jacket 2, and the refrigerant supply pump 4 is interposed in the passage, and On the suction side and the discharge side of the supply pump 4, a fourth solenoid valve 17 and a second solenoid valve 18, each of which is a three-way solenoid valve, are provided as flow path switching means.

Reference numeral 21 is a reservoir tank provided outside the refrigerant circulation system mainly composed of the water jacket 2 and the condenser 3, which is opened to the atmosphere through a cap 22 having a ventilation function, and the water tank The first auxiliary refrigerant passage 16 and the second and third auxiliary refrigerant passages 2 are installed at the same height as the jacket 2 and at the bottom thereof.
3,24 are connected. The first auxiliary refrigerant passage 16 is provided with a normally open third solenoid valve 25 in the passage. Further, the second auxiliary refrigerant passage 23 is connected to the fourth electromagnetic valve 17, and the third auxiliary refrigerant passage 24 is connected to the second electromagnetic valve 18 to form a refrigerant circulation passage.
Connected to 15. The fourth electromagnetic valve 17 connects the "passage C" that connects the suction port of the coolant supply pump 4 to the lower tank 13 via the coolant circulation passage 15 and the reservoir tank 21 via the second auxiliary coolant passage 23. It can be switched to the "flow path D". The second solenoid valve 18 communicates with a “flow passage B” that connects the discharge port of the coolant supply pump 4 to the water jacket 2 via the coolant circulation passage 15 and to the reservoir tank 21 via the third auxiliary coolant passage 24. It can be switched to the "flow path A".

On the other hand, the discharge pipe mounting part which is the uppermost part of the refrigerant circulation system described above.
An air discharge passage 26 for discharging the air in the system is connected to 8a, and the tip of the air discharge passage 26 is a reservoir for collecting the liquid-phase refrigerant that overflows at the same time when the air is discharged. It opens into the tank 21. A normally closed first electromagnetic valve 27 is interposed in the air discharge passage 26.

The solenoid valves 27, 18, 25, 17 and the coolant supply pump 4 and the cooling fan 14 are driven and controlled by a control device 31 using a so-called microcomputer system. Specifically, they are provided in the water jacket 2. First liquid level sensor 3
2, temperature sensor 33, the second liquid level sensor provided in the lower tank 13
The control described later is performed based on the detection signals of 34 and the negative pressure switch 35 provided at the top of the circulation system.

Here, the first and second liquid level sensors 32, 34 are, for example, float type sensors using reed switches, etc., and detect whether the refrigerant liquid level has reached a set level on or off. The detection level of the first liquid level sensor 32 is set at a height position approximately in the middle of the cylinder head 6, and the detection level of the second liquid level sensor 34 is the opening of the first auxiliary refrigerant passage 16. The height is set slightly above. The temperature sensor 33 is composed of, for example, a thermistor or the like, and is usually provided at a position to be immersed in the liquid phase refrigerant or a position to be a gas phase refrigerant region.
The temperature of the refrigerant inside is detected. The negative pressure switch 35
A diaphragm that responds to the pressure difference between the atmospheric pressure and the system pressure is used to detect whether or not the system pressure is negative with respect to the atmospheric pressure in the environment of use, regardless of highland or lowland. ,
Specifically, the operating pressure is set to about -30 mmHg to -50 mmHg.

Various sensors for detecting other engine operating conditions are not shown.

Reference numeral 41 denotes a heater core for heating provided in the vehicle interior 42, the lower refrigerant inlet is connected to the cylinder block 5 side of the water jacket 2 via the heater inlet passage 43, and the upper refrigerant outlet is the heater outlet. It is connected via a passage 44 to a portion which is a normal liquid phase refrigerant region on the cylinder head 6 side. A heater pump 45 circulates the liquid-phase refrigerant between the water jacket 2 and the heater core 41, and is interposed in the heater outlet passage 44. Then, on the discharge side of the heater pump 45, a relatively thin refrigerant mixing passage 46 is branched from the heater outlet passage 44,
Moreover, its tip is connected to the connecting pipe 8 upstream of the capacitor 3. The heater pump 45 is connected to the heater inlet passage 43.
It may be provided in the. Also, the heater pump 45
Is configured to operate in conjunction with a heater switch (not shown).

Next, the control of the boiling cooling device and the operation of each part will be described.

First, when the engine is started, the liquid phase refrigerant (for example, 30
~ 50% ethylene glycol aqueous solution is used)
And discharge the air that is a non-condensable gas. That is, the first electromagnetic valve 27 is "open", the second electromagnetic valve 18 is "flow path B", the third electromagnetic valve 25 is "closed", and the fourth electromagnetic valve 17 is "flow path D". 4 is driven for a certain period of time, and the liquid-phase refrigerant is forcibly fed into the system from the reservoir tank 21 outside the system. As a result, the air remaining in the system is collected in the upper part of the system and then discharged to the outside of the system through the air discharge passage 26.

Sufficient time (for example, several tens) to fill the system with liquid refrigerant
After about 2 seconds), the first electromagnetic valve 27 is “closed”, the third electromagnetic valve 25 is “open”, the refrigerant supply pump 40 is turned off, and the system stands by. Since the liquid-phase refrigerant in the water jacket 2 is in a stagnant state, the temperature rises quickly. After that, when the temperature detected by the temperature sensor 23 reaches the target temperature, the third solenoid valve 25 is closed and the system is closed. The target temperature is within the range not exceeding the boiling point of the refrigerant under normal pressure, for example 80
Within the range of up to 105 ° C, it is set to the optimum value in sequence according to the operating conditions such as engine load and rotation speed. If the heater switch is ON, the heater pump 45 will operate,
In this state, the refrigerant circulates only on the water jacket 2 side and does not flow to the condenser 3 side, so there is no risk of delaying warm-up.

After the above warm-up control is completed and the system is hermetically closed, the refrigerant liquid pump 4 is turned on and off to maintain the coolant level in the water jacket 2, the cooling fan 14 is turned on and off, and the condenser 3 is turned on. The temperature control by raising and lowering the liquid level of the refrigerant is repeatedly executed until the key is turned off, and efficient cooling using the boiling / condensing cycle of the refrigerant is performed. That is, as a result of boiling in the water jacket 2, when the liquid level of the refrigerant falls below the set level of the first liquid level sensor 32, the second electromagnetic valve 18 is set to “flow path B” and the fourth electromagnetic valve 17 is set to “flow”. The refrigerant supply pump 4 is turned on in the state of "path C", and the liquid phase refrigerant is replenished from the lower tank 13 to the water jacket 2. If there is no liquid-phase refrigerant in the lower tank 13, the fourth solenoid valve 17 may be used as the "flow path D" as necessary in the reservoir tank.
Supply liquid refrigerant from 21. As a result, the liquid level of the refrigerant in the water jacket 2 is always maintained near the set level of the first liquid level sensor 32. Further, the cooling fan 14 controls ON / OFF in a relatively fine temperature range of about “target temperature ± 0.5 ° C.”. As a result, relatively fine adjustment of the condensation performance of the condenser 3 is performed with good responsiveness. Further, when the detected temperature is relatively large (for example, about 2 to 4 ° C.) from the target temperature, the liquid phase refrigerant is moved between the reservoir tank 21 and the condenser 3 so that the substantial heat radiation area of the condenser 3 is reduced. Variable control. Specifically, if the detected temperature is higher than the target temperature, the liquid supply refrigerant 4 is supplied to the liquid-phase refrigerant by the second electromagnetic valve 18 in the “flow path A” and the fourth electromagnetic valve 17 in the “flow path C”. The refrigerant is discharged and the liquid level of the refrigerant in the condenser 3 is lowered.
As a result, the heat dissipation capability of the capacitor 3 is increased, the boiling point is immediately lowered, and the system temperature is rapidly lowered. Since the target temperature is set lower than the boiling point of the refrigerant under normal pressure as described above, normally, the depressurized boiling occurs only after the proper amount of the liquid-phase refrigerant is discharged from the condenser 3 after starting. become. On the contrary, if the detected temperature is lower than the target temperature, the third solenoid valve 25 is opened, and the liquid phase refrigerant is introduced from the reservoir tank 21 to the condenser 3 by utilizing the pressure difference between the inside and outside of the system, and the liquid level of the refrigerant is changed. To raise. As a result, the heat dissipation capability of the capacitor 3 is suppressed, and the temperature inside the system rises quickly. That is, the system temperature can be variably controlled with high accuracy without being affected by a disturbance such as a vehicle running wind.

On the other hand, when a heater switch (not shown) is turned on in the winter season, the heater pump 45 is activated and the water jacket 2
The high temperature liquid-phase refrigerant therein is circulated and supplied to the heater core 41. Then, a part of the liquid-phase refrigerant returning from the heater core 41 to the water jacket 2 flows from the heater outlet passage 44 to the refrigerant mixing passage 46.
To the connecting pipe 8. The liquid-phase refrigerant guided to the connecting pipe 8 is sent to the condenser 3 by the vapor flow flowing through the vapor passage 9. That is, the refrigerant in the water jacket 2 having a high ethylene glycol concentration is mixed little by little with the refrigerant on the condenser 3 side, and the concentration can be made uniform. Instead of making the refrigerant mixing passage 46 thin, it is possible to adjust the flow rate by providing an orifice.

Next, after the engine is stopped, the first solenoid valve 27, which is a normally closed solenoid valve, is "closed" and the third solenoid valve 25, which is a normally opened solenoid valve, is "open" as the power is turned off. Therefore, the liquid-phase refrigerant moves from the reservoir tank 21 into the system as the temperature decreases, that is, the pressure decreases. Eventually, the inside of the system is almost completely filled with the liquid-phase refrigerant, and air intrusion during stoppage is prevented. here,
As described above, since the refrigerant in the water jacket 2 is fed into the condenser 3 little by little during operation, the difference in ethylene glycol concentration between the two is kept relatively small. As a result, it is possible to reliably prevent freezing of the refrigerant while the engine is stopped.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment and can be configured as a boiling cooling device of various types. It goes without saying that the present invention can also be applied to the case where a refrigerant other than an ethylene glycol aqueous solution is used.

Effects of the Invention As is clear from the above description, in the boiling cooling apparatus for an internal combustion engine according to the present invention, the freezing of the refrigerant in each part such as the condenser and the cooling supply pump due to the uneven distribution of the antifreeze component in the refrigerant is ensured. It can be prevented. In addition, since the refrigerant is introduced using the heater pump, no special operation is required in situations where freezing occurs, the number of parts is prevented from increasing, and useless operation occurs in summer, etc. There is no.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view showing an embodiment of the present invention. 1 ... Internal combustion engine, 2 ... Water jacket, 3 ... Condenser, 4 ... Refrigerant supply pump, 9 ... Steam passage, 13
...... Lower tank, 14 ...... Cooling fan, 15 ...... Refrigerant circulation passage, 16 ...... First auxiliary refrigerant passage, 17 ...... Fourth solenoid valve, 18 ...
… Second solenoid valve, 21 …… Reservoir tank, 23 …… Second auxiliary refrigerant passage, 24 …… Third auxiliary refrigerant passage, 25 …… Third solenoid valve, 26 …… Air discharge passage, 27 …… First Solenoid valve, 31 ... Control device, 32 ... First liquid level sensor, 33 ... Temperature sensor, 34
...... Second liquid level sensor, 35 ...... negative pressure switch, 41 ...... heater core, 43 ...... heater inlet passage, 44 …… heater outlet passage, 45 …… heater pump, 46 …… refrigerant mixing passage.

Claims (1)

[Claims] 1. A water jacket in which a liquid-phase refrigerant is stored to a predetermined level, a condenser into which refrigerant vapor generated in the water jacket is introduced, a condenser disposed between the condenser and the water jacket, and A refrigerant supply pump that replenishes the liquid-phase refrigerant from the condenser to the water jacket so as to maintain the liquid level in the water jacket at the predetermined level, and a heater that circulates the liquid-phase refrigerant in the water jacket to the heater core for heating the passenger compartment. In a boiling cooling apparatus for an internal combustion engine comprising a pump for cooling, a refrigerant mixing passage is branched from a heater refrigerant passage on the discharge side of the heater pump, and its tip is connected to the inlet side of the condenser. A boiling cooling device for internal combustion engines.