JPS61171819A - Evaporative cooling device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent droppage of the concentration of antifreeze component at the condenser side by branching a refrigerant mixing path from the refrigerant path of cabin warming heater and coupling the tip to the inlet side of condenser. CONSTITUTION:Upon turning on of heater switch in Winter season, a heater pump 45 will function to circulate high temperature liquid phase refrigerant in water jacket 2 to a heater core 41. A portion of liquid phase refrigerant returning from the heater core 41 to the water jacket 2 is led to a coupling tube 8, then fed to a condenser 3. consequently, droppage of concentration of antifreeze component at the condenser side can be prevented.

Description

[Detailed Description of the Invention] The invention in the field of industrial application stores liquid phase refrigerant up to a predetermined level in a water jacket, cools various parts of the internal combustion engine by boiling it, and cools the generated refrigerant. The present invention relates to an evaporative cooling system for an internal combustion engine in which steam is condensed in a condenser and reused.

Conventional Technology As a cooling device for an internal combustion engine, a boiling cooling device that utilizes the boiling and condensing cycle of a refrigerant (cooling water) was proposed in Japanese Patent Publication No. 57-57608, etc., in place of the conventional water-cooled cooling device. However, the present applicant has developed this further and has already filed various applications (for example, Japanese Patent Application No. 1983-1 '45470, Japanese Patent Application No. 58-2 '45470, Japanese Patent Application No. 58-2 '45470,
No. 28146.

Patent Application No. 100156/1982).

This consists of a water jacket in which liquid phase refrigerant is stored up to a predetermined level, a condenser connected via a steam passage to a steam outlet at the top of this water jacket, and a condenser connected from the bottom of the condenser where liquefied refrigerant is temporarily stored to the water jacket. A closed refrigerant circulation system is formed mainly with a refrigerant supply pump that circulates and supplies liquid refrigerant to the refrigerant circulation system. By moving the air, which is a non-condensable gas, is discharged.While the engine is running, the refrigerant liquid level in the water shaker v) is monitored by a liquid level sensor and the refrigerant supply pump is controlled to maintain the liquid level. This is to maintain it at a predetermined level. According to a 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 refrigerant boiling point.

Problems to be Solved by the Invention By the way, the refrigerant for this type of boiling cooling device is a combination of water mixed with ethylene glycol or the like as an antifreeze, from the viewpoints of ease of handling, large latent heat of vaporization, price, etc. It has been considered to use a solution containing a large amount of rust preventive agent, but since an aqueous solution of ethylene glycol is a non-azeotropic mixture, the vapor of the aqueous solution contains almost no ethylene glycol, and the water vapor Only. Example: 50% (wt%) of ethylene glycol
The vapor of the aqueous solution contains only about 29% ethylene glycol.

Therefore, when the boiling cooling device described above is continuously operated, a large amount of ethylene glycol is unevenly distributed in the water jacket, and the ethylene glycol concentration becomes extremely low on the condenser side. Therefore, there is a risk that the capacitor may freeze inside the capacitor during the winter, damaging the capacitor, or that the solenoid valve or refrigerant supply pump may freeze and malfunction.

Means for Solving the Problems In order to prevent the uneven distribution of antifreeze components in the refrigerant as described above, the present invention is equipped with a heater pump that circulates the liquid phase refrigerant in the water jacket to the heater core for heating the vehicle interior. The invention is characterized in that a refrigerant mixing passage is branched from the heater refrigerant passage on the discharge side of the heater pump, and its tip is connected to the inlet side of the condenser.

The heater pump is linked to the heater switch and is activated when heating is required, but in situations where the refrigerant freezes, heating is always required when the engine is running.
The heater pump is driven. By driving this heater pump, the liquid phase refrigerant in the water jacket flows through the heater core. Then, a part of the liquid phase refrigerant is separated from the heater refrigerant passage, flows into the refrigerant mixing passage, and is sent to the condenser. This suppresses a decrease in the concentration of antifreeze components on the capacitor side.

Embodiment The figure shows one embodiment of the boiling cooling device according to the present invention. In the figure, 1 is an internal combustion engine equipped with a water jacket 2, 6 is a condenser for condensing a gas phase refrigerant, and 4 is an internal combustion engine equipped with a water jacket 2. Each figure shows an electric refrigerant supply pump.

The water jacket 2 is formed to cover both the cylinder block 5 and the cylinder so as to surround the cylinder and the outer peripheral part 1 of the combustion engine 1, and the upper part, which is normally a gas phase space, is The cylinders communicate with each other, and a steam ratio lower is provided at an appropriate position above the cylinders. This steam ratio lower communicates with the upper part 6a of the condenser via a connecting pipe 8 and a steam passage 9t, and the connecting pipe 8 has a discharge pipe attachment part 8a which is the top of the refrigerant circulation system. It is formed in a shape that stands upward, and the carriage 10 seals the upper opening.

The condenser 6 includes an upper tank 11 having the above-mentioned population a, a core section 12 mainly consisting of fine tubes along the vertical direction, and a lower tank 16 that temporarily stores the liquefied refrigerant condensed in the core section 12. It is installed in a position such as the front of the vehicle where it can receive the wind from when the vehicle is running, and is further provided with an electric cooling fan 14 for forced cooling on the front or back of the vehicle. Further, 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 refrigerant circulation passage 15
The other end is connected to the 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 the suction of the refrigerant supply pump 4 is side, discharge side, respectively.
No. 4'l consisting of a three-way solenoid valve as a flow path switching means! a
A valve 17 and a second electric valve 18 are interposed.

Reference numeral 21 denotes a reservoir tank provided outside the refrigerant circulation system mainly consisting of the water jacket 2 and the condenser 6, which is open to the atmosphere through a cap 22t having a ventilation function, and is It is installed at approximately the same height as jacket 2, and the above #! l auxiliary refrigerant passage 16 and a second auxiliary refrigerant passage 16; A third auxiliary refrigerant passage 23,24 is connected. The first auxiliary refrigerant passage 16 is provided with a normally open type 311E magnetic valve 25 therein. Further, the second auxiliary refrigerant passage 26 is connected to the refrigerant circulation passage 15 via a fourth solenoid valve 17, and the third auxiliary refrigerant passage 24 is connected to the refrigerant circulation passage 15 via a second solenoid valve 18. The fourth solenoid valve 17 communicates the suction boat of the refrigerant supply pump 4 with the lower tank 13 via the refrigerant circulation passage 1st, and the reservoir tank 21 via the second auxiliary refrigerant passage 23. It is configured so that it can be switched to "flow path D". The second solenoid valve 18 connects the discharge port of the refrigerant supply pump 4 to the water tank 2 via the refrigerant circulation path 15, and to the reservoir tank 21 through the third auxiliary refrigerant path 24t. It is configured so that it can be switched to the "flow path A" to be communicated with.

On the other hand, an air discharge passage 26 for discharging air in the system is connected to the discharge pipe attachment part 43a, which is the top of the refrigerant circulation system, and when the air is discharged, it overflows into F1#. In order to recover the outgoing liquid phase refrigerant, the air exhaust passage 2
The tip of 6 opens into the reservoir tank 21. A normally closed first solenoid valve 27 is interposed in the air exhaust passage 26 .

f″E'f)1t(i!i”27・18・25・17.
! :#! *.

The supply bong 4 and the cooling fan 14 are driven and controlled by a control device 31 using a so-called microcomputer system, and specifically, a first liquid level sensor 32 provided in the water jacket 2, a temperature sensor 66, The lower tank 13 has 9 jl! Control described later is performed based on detection signals from the two liquid level sensors 64 and the negative pressure switch 5 provided at the top of the circulation system.

Here, the above 1. The second liquid level sensor 52,54 is a float type sensor using a reed switch, for example, and detects whether the refrigerant liquid level has reached a set level in an on/off manner. The liquid level sensor 62 has its detection level set at a height approximately in the middle of the cylinder head 6, and the second liquid level sensor filter 4 has its detection level set at a position slightly above the opening of the first auxiliary refrigerant passage 16. It is set at a height of . Further, the temperature sensor 66 is composed of, for example, a thermistor, and is normally installed at a position immersed in the liquid phase refrigerant or at a position in the gas phase refrigerant region to detect the temperature of the refrigerant within the water jacket 2. In addition, the negative pressure switch 65 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 usage environment, whether in highlands or lowlands. It detects whether or not, specifically -30w Hg ~ -50
The operating pressure is set to about ta Hg.

Note that various sensors for detecting other engine operating conditions are not shown.

Reference numeral 41 denotes a heater core for heating provided in the vehicle compartment 42, the lower refrigerant inlet is connected to the cylinder block 5 side of the water jacket 2 via the heater inlet passage 45t, and the upper refrigerant outlet is the heater outlet. It is connected to a portion of the cylinder head 6@ that is normally a liquid phase refrigerant region via a passage 44t.

45 connects the liquid phase refrigerant to the quarter jacket 2 and heater core 4.
It is a heater pump for circulating between 1 and 1.
The heater outlet passage 44 is interposed. On the discharge side of this heater pump 45, a heater outlet passage 44 is provided.
A relatively narrow refrigerant mixing passage 46 is branched from the refrigerant mixing passage 46, and its tip is connected to the connecting pipe 8 upstream of the condenser 6. Incidentally, it may be provided between the heater pump 45t and the heater inlet passage 46. Further, the heater pump 45 is configured to operate in conjunction with a heater switch (not shown).

Next, the control of the evaporative cooling device and the operation of each part will be explained.

First, when the engine starts, the system is temporarily filled with liquid phase refrigerant (for example, 3
(0 to 5096 ethylene glycol aqueous solution is used), and air, which is a non-condensable gas, is discharged. That is, the first solenoid valve 27 is "open" and the second solenoid valve 18 is "open".
The refrigerant supply pump 4 is driven for a certain period of time with the flow path BJ, the third solenoid valve 25 set to "closed" and the fourth solenoid valve 17 set to "flow path D", and the liquid phase refrigerant f is supplied from the outside of the system to the reservoir tank 21 into the system. :I
i! Send them to the 11th system. As a result, the air remaining in the system is collected in the upper part of the system and then exhausted to the outside of the system via the air exhaust passage 26.

Sufficient time for the system to be filled with liquid phase refrigerant (e.g.
After approximately 0 seconds have passed, the first solenoid valve 27 is closed, and the third solenoid valve 27 is closed.
The solenoid valve 25 is opened, the refrigerant supply pump 4 is turned off, and the system waits until that time. Since the liquid phase refrigerant in the water shaker 2 is in a stagnation state, the temperature quickly rises. Thereafter, when the temperature detected by the temperature sensor 23 reaches the target temperature, the third solenoid valve 25 is "closed" to seal the inside of the system. The target temperature is successively optimally set within a range that does not exceed the boiling point of the refrigerant under normal pressure, for example within a range of about 80 to 105°C, depending on operating conditions such as engine load and rotational speed. If the heater switch 2>E is ON, the heater pump 45 will operate, but in this state, the refrigerant circulates only on the watershake butt 2 side and does not flow to the condenser 3 side, which may delay warm-up. There isn't.

After the above warm-up control is completed and the system is sealed, the water jacket 2 is turned on and off by turning the refrigerant supply pump 4 on and off.
Maintaining the refrigerant liquid level in the tank and turning the cooling fan 14 on and off
And temperature control by raising and lowering the refrigerant liquid level in the condenser 6 is carried out using the key 0FF1''''repeat')1. As a result of boiling in the quarter tank 2, when the refrigerant liquid level falls below the set level of the first liquid level sensor 62, the second solenoid valve 18 is closed to the flow path BJ, and the fourth solenoid valve 17 is closed to the flow path BJ. C", refrigerant supply bong 7'4t-
Turn it on and replenish liquid phase refrigerant from the lower tank 13 to the water jacket 2. In addition, if there is no liquid phase refrigerant in the lower tank 13, the fourth solenoid valve 17t may be activated as necessary.
-r flow path D'', liquid phase refrigerant is replenished from the reservoir tank 21. As a result, the refrigerant liquid level in the water jacket 2 is always maintained near the level set by the first liquid level sensor 62. Well, the cooling fan 14 has a "target temperature ±0.5°C"
ON/OFF control is performed within a relatively small temperature range.

As a result, relatively fine adjustment of the condensing performance of the condenser 3 can be made with good responsiveness.

Also, the detected temperature is relatively larger than the target temperature (e.g. 2~
(approximately 4° C.), the liquid phase refrigerant is moved between the reservoir tank 21 and the condenser 6 to variably control the substantial heat dissipation area of the condenser 3. Specifically, if the detected temperature is higher than the target temperature, the second solenoid valve 18 is
J, fourth electric valve 171-r flow path C'', the liquid phase refrigerant is discharged by the refrigerant supply pump 4, and the refrigerant liquid level in the condenser 6 is lowered. As a result, the heat dissipation capacity of the capacitor 3 increases, 4 the boiling point immediately decreases, and the system temperature quickly decreases. As mentioned above, the target temperature is set lower than the boiling point of the refrigerant under normal pressure, so normally, reduced pressure boiling does not occur until an appropriate amount of liquid phase refrigerant is discharged from the condenser 3 after startup. become. Conversely, 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 into the condenser 3 using the pressure difference inside and outside the system, and the refrigerant liquid level is lowered. raise. As a result, the heat dissipation ability of the capacitor 3 is suppressed, and the temperature within the system quickly rises. That is, the system temperature t
- Highly accurate variable control is possible without being affected by disturbances such as vehicle wind.

On the other hand, when a heater switch (not shown) is turned on during winter, etc., the heater pump 45 is activated, and the high temperature liquid phase refrigerant in the water jacket 2 is circulated and supplied to the heater core 41. Then, from the heater core 41 to the water jacket 2
A part of the liquid phase refrigerant returning to the heater outlet passage 44 is diverted to a refrigerant mixing passage 46 and guided to the connecting pipe 8. The liquid phase refrigerant introduced into the connecting pipe 8 is sent to the condenser 3 by a vapor flow flowing through the vapor passage 9. That is, the refrigerant in the water jacket 2, which has a high concentration of ethylene glycol, is mixed little by little with the refrigerant on the condenser 6 side, thereby making the concentration uniform.

Incidentally, instead of forming the refrigerant mixing passage 46 narrowly, it is also possible to provide an orifice to adjust the flow rate.

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

Although one embodiment of the present invention has been described above in detail, the present invention is not limited to the above embodiment, and can be configured as various types of boiling cooling devices. Needless to say, the present invention can also be applied when using something other than the ethylene glycol aqueous solution as the secondary refrigerant.

Effects of the Invention As is clear from the above explanation, the boiling cooling system for an internal combustion engine according to the present invention can reliably prevent the refrigerant from freezing in various parts such as the condenser and the cooling supply pump due to uneven distribution of antifreeze components in the refrigerant. It can be prevented.

In addition, since refrigerant is introduced using a heater pump, special operations are not recommended in situations where freezing occurs, and an increase in the number of parts is prevented, resulting in unnecessary operation in summer, etc. Never.
t

[Brief explanation of the drawing]

The figure is a configuration explanatory diagram 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...2nd'#It magnetic valve, 21...Lizard tank, 2'6...2nd auxiliary refrigerant passage, 24...3rd auxiliary refrigerant passage , 25...
31st is a magnetic valve, 26... air discharge passage, 27... first solenoid valve, 31... control device, 62... first liquid level sensor, 33... temperature sensor, 64... ...Second liquid level sensor, 35...Negative pressure switch, 41...Heater core,
46... Heater inlet passage, 44... Heater outlet passage, 45... Heater pump, 46... Refrigerant mixing passage.

Claims (1)

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