JPH0410327Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a boiling cooling device for an internal combustion engine that utilizes the latent heat of vaporization of a refrigerant.

(Prior art) A water-cooled cooling system that circulates cooling water between an engine water jacket and a radiator requires a large amount of cooling water to satisfy the required amount of heat dissipation due to the efficiency of the radiator and the heat capacity of the water. It was necessary to circulate the water, which caused a large drive loss in the water pump.

Therefore, a cooling device has been proposed that uses the latent heat of vaporization of the cooling water to cool the engine with a small amount of circulating water. This is a cooling system that uses a cycle in which the cooling water (liquid phase refrigerant) stored in the water jacket is boiled using the heat generated by the engine, and the generated steam is condensed and liquefied in a radiator (condenser) and returned to the water jacket. Yes (Tokukaisho
56-32027, Published Patent Publication No. 1983-500140, etc.).

(Problem that the invention aims to solve) By the way, in order to obtain good cooling performance in such a cooling device, air in the cooling circuit is discharged to the outside by steam generated in the water jacket. There is something. In this case, the cooling device is equipped with an auxiliary tank storing a predetermined liquid phase refrigerant, and the vapor discharged outside the circuit is recovered into the liquid phase of the auxiliary tank.

However, if this is done, for example, if a mixture of water and antifreeze (ethylene glycol, etc.) is used as the refrigerant, only the water will boil and evaporate from the water jacket, resulting in the only liquid collected in the auxiliary tank. . Therefore, there was a problem in that the concentration of antifreeze in the liquid phase of the auxiliary tank gradually became diluted, making it easier to freeze.

(Means for solving the problem) In order to solve the problem, this invention uses an engine water jacket that is mostly filled with liquid phase refrigerant and a condenser that maintains the interior in a gas phase. , an evaporative cooling device for an internal combustion engine in which a vapor passage through which refrigerant vapor flows and a refrigerant passage through which liquefied refrigerant returns are connected to form a closed circuit in which the refrigerant circulates; A discharge passage connected to the closed circuit is provided at a portion above the refrigerant liquid level in the water jacket, and this discharge passage is opened into the liquid in the auxiliary tank via a release valve, while the water jacket A pump that sends the liquid refrigerant in the auxiliary tank to the auxiliary tank, and a return passage that returns the liquid refrigerant in the auxiliary tank to the water jacket via a cutoff valve are provided. and control means for opening the opening.

(Function) Therefore, the air in the closed circuit is pushed out through the discharge passage by the steam generated in the water jacket, and the steam that flows out along with this becomes liquid phase refrigerant and is collected in the auxiliary tank. The liquid phase refrigerant in this auxiliary tank is mixed and replaced with the liquid phase refrigerant in the water jacket by a pump when the engine is stopped. This prevents the concentration of antifreeze in the refrigerant in the auxiliary tank from decreasing when antifreeze is used as the refrigerant.

(Embodiment) The figure shows an embodiment of the present invention, in which 1 is the engine (main body), 2 is a water jacket filled mostly with liquid phase refrigerant such as water, and 3 is the refrigerant from the water jacket 2. A cooling fan 4 supplies cooling air to the condenser 3, which cools and liquefies vapor.

A water jacket 2 is formed from a cylinder block to a cylinder head so as to surround the cylinder and combustion chamber of the engine 1, and a condenser 3 is disposed above the water jacket 2.

The water jacket 2 communicates with the inlet (upper part) 6 of the condenser 3 via a steam passage 5 that opens into the gas phase space above the water jacket 2 so as to form a closed circuit with the condenser 3. An outlet portion (lower portion) 7 communicates with the liquid phase of the water jacket 2 via a refrigerant passage 8 .

A water trap 9 for gas-liquid separation is installed in the middle of the steam passage 5, and a return passage 11 with a check valve 10 interposed between the water trap 9 and the water jacket 2 is formed.

A check valve 12 is interposed in the middle of the refrigerant passage 8 to prevent the liquid level of the refrigerant in the water jacket 2 from decreasing due to the pressure of the refrigerant vapor.

On the other hand, an auxiliary tank 13 storing a predetermined amount of liquid-phase refrigerant is provided, and a first
A second passageway 14 (discharge passageway) and a second passageway opening into the gas phase portion (near the liquid level in this case) in the auxiliary tank 13 and connecting to the steam passageway 5 above the water trap 9.
A passage 15 is formed.

A check valve 16 and a release valve 17 consisting of a solenoid valve are interposed in the first passage 14, and the release valve 17 opens and closes the first passage 14 as described later.

A negative pressure responsive valve 18 is installed in the second passage 15 to open the second passage 15 in response to negative pressure when the pressure in the steam passage 5 is negative. Note that the auxiliary tank 13 is communicated with the outside air through an air vent 19 at the top.

Further, pressure switches 20 and 21 are installed in the steam passage 5 near the water jacket 2 to conduct the refrigerant vapor depending on the pressure of the refrigerant vapor.

When the pressure of the steam reaches a set value, the pressure switch 20 operates a relay 22 provided between the power source and the cooling fan 4, thereby driving the cooling fan 4.
When the value becomes lower than the set value, the cooling fan 4 is stopped.

The pressure switch 21 opens the release valve 17 when the steam pressure is lower than a set value, and operates a relay 23 provided between the power source and the release valve 17 to close the release valve 17 when the steam pressure is higher than the set value. It's getting old.

A level sensor 24 detects the lower limit level of the refrigerant liquid level in the water jacket 2, and is designed to activate an alarm buzzer 25 etc. when the refrigerant liquid level drops to the level of the level sensor 24.

Further, when the amount of evaporation increases abnormally, the relief valve 26 releases the steam to the outside to prevent the pressure from increasing in order to prevent damage to the inside of the steam system due to the pressure increase.

When the engine is stopped, the inside of the cooling system is filled with a predetermined amount of refrigerant and air, and the release valve 17 of the first passage 14 is in an open state.

Then, when the engine is started, the temperature of the refrigerant in the water jacket 2 rises due to the heat generated by the engine, and when the refrigerant eventually begins to boil, steam is generated while absorbing the latent heat of vaporization.

This steam flows from the water jacket 2 through the steam passage 5 to the upper condenser 3.
Accompanied by this steam, the air in the water jacket 2 and steam passage 5 is forced toward the condenser 3,
Furthermore, a first passage 14 from the lower part 7 of the capacitor 3
The water is discharged to the auxiliary tank 13 via the auxiliary tank 13.

At this time, some steam is also discharged along with the air, but since the first passage 14 opens into the stored liquid in the auxiliary tank 13, the steam is condensed by the stored liquid and remains in the tank 13. After this, when the amount of steam generated increases and the pressure of the steam increases to a certain extent,
The pressure switch 21 is turned on and the open valve 17 of the first passage 14 is closed.

Then, normal cooling operation begins in this state, but
In this case, when the amount of steam is not so large,
Heat is radiated and condensed from the steam in the condenser 3 using only the running wind. When the amount of steam increases and the steam pressure reaches a predetermined pressure, the pressure switch 20 is turned on and the cooling fan 4 is driven to perform forced cooling. Wind promotes heat dissipation and condensation of steam.

Therefore, the driving power of the cooling fan 4 is reduced, and the engine is cooled accurately and responsively.

Further, the refrigerant condensed and liquefied in the condenser 3 falls by gravity from the lower part 7 of the condenser through the refrigerant passage 8, and is returned to the water jacket 2 below through the check valve 12.

Therefore, it is possible to circulate the refrigerant without using a pump or the like, simplifying the structure of the device, and eliminating the need for pump power or control for refrigerant circulation.

In addition, at the beginning of cooling, the steam passage 5 is
The air in the system introduced into the condenser 3 through the steam is heavier than steam, so it stays in the lower part of the condenser 7, and most of it is discharged to the atmosphere side (auxiliary tank 13) through the first passage 14. However, at this time, the air that could not be completely discharged and the air remaining in the refrigerant passage 8 are cooled in the condenser 3 and introduced into the water jacket 2 through the refrigerant passage 8 together with the liquefied refrigerant. It is heated by the engine and is introduced into the condenser 3 through the steam passage 5 again together with the steam, and is then passed from the lower part of the condenser 7 to the first passage 1.
4 to the atmosphere. By repeating this cycle, the gas phase space in the system is almost filled only with steam, so that the condenser 3 dissipates heat only by steam, ensuring efficient heat dissipation and condensation.

On the other hand, since the gas phase space in the system is only steam,
When the engine is stopped and the temperature in the system drops, steam condenses and the pressure in the system drops significantly. At this time, the negative pressure responsive valve 18 in the second passage 15 opens in response to this pressure drop. It can be done.

Therefore, air is sucked into the system from the second passage 15, and negative pressure is prevented. In addition, in this case, since the second passage 15 opens near the liquid level stored in the auxiliary tank 13, the refrigerant equivalent to the vapor discharged into the liquid in the auxiliary tank 13 as air is discharged when the engine is started is removed. By raising the liquid level of the auxiliary tank 13 by a corresponding amount above the opening of the second passage 15, the liquid is sucked into the system and recovered as air is sucked. Thereby, the refrigerant in the system is always maintained at an appropriate amount.

In such a boiling cooling device, the liquid phase refrigerant in the water jacket 2 is transferred to the auxiliary tank 1.
3, and a return passage 29 for returning the liquid phase refrigerant in the auxiliary tank 13 to the water jacket 2 via a cutoff valve (electromagnetic valve) 28.

This pump 27 also serves as a pump that sends the liquid phase refrigerant in the water jacket 2 through the heater passage 31 to a heater core 30 for heating the passenger compartment, for example.
A supply passage 32 branched from the heater passage 31 on the upstream side of the pump 27 is connected to the auxiliary tank 13, and the passage 3 on the heater core 30 side is connected to the branch part 33.
A switching valve (three-way solenoid valve) 34 that selectively opens the supply passage 32 and the supply passage 32 is interposed.

On the other hand, the return passage 29 is connected to the lower part of the water jacket 2 and is approximately connected to the second passage 1.
5, it is opened and connected to a predetermined liquid level position of the auxiliary tank 13.

Then, the pump 27, the switching valve 34, and the cutoff valve 28
A control circuit (control means) 35 is provided for driving the pump 27, and when the engine stops, the control circuit 35 controls the pump 27 to be driven for a certain period of time immediately after the engine stops, and also controls the supply passage 32 for a certain period of time.
The switching valve 34 and the cutoff valve 28 are driven and controlled so as to open the return passage 29.

With this configuration, when the engine is started, a portion of the steam generated in the water jacket 2 flows out into the auxiliary tank 13 as air is discharged.
Therefore, if antifreeze is used as a refrigerant, the auxiliary tank 1
The concentration of antifreeze in the refrigerant in 3 gradually decreases,
When the engine is stopped after the operation is completed, the pump 27 is driven for a certain period of time immediately after the engine is stopped, and the supply passage 32 and the return passage 29 are opened by the switching valve 34 and the cutoff valve 28.

Then, the liquid refrigerant in the water jacket 2 is pumped through the heater passage 31 and the supply passage 32 by the pump 27.
The liquid phase refrigerant in the auxiliary tank 13 flows into the water jacket 2 through the return passage 29.

As a result, when the engine is stopped, the auxiliary tank 13
The liquid-phase refrigerant in the auxiliary tank 13 is mixed with and replaced with the liquid-phase refrigerant in the water jacket 2. Therefore, even if antifreeze is used as the refrigerant, a decrease in the concentration of antifreeze in the refrigerant in the auxiliary tank 13 can be avoided, preventing freezing. It can definitely be prevented.

Further, the concentration of antifreeze in the water jacket 2 can be maintained at an appropriate value, and therefore good cooling performance by boiling cooling is maintained.

Furthermore, since the return passage 29 opens at a predetermined liquid level position in the auxiliary tank 13, even if the refrigerant is allowed to flow as described above, the refrigerant liquid level in the water jacket 2 and the auxiliary tank 13 remains at an appropriate level. .

Incidentally, in this embodiment, the pump provided for the heater is also used as the pump 27, but of course, a new pump provided exclusively for the heater may be provided.

(Effects of the invention) As described above, according to the invention, since the air in the closed circuit is exhausted by the generated steam, the gas phase space in the closed circuit becomes only steam, and excellent cooling performance is obtained. The liquid phase refrigerant in the auxiliary tank, which collects the vapor that flows out with the air, is mixed and replaced with the liquid phase refrigerant in the water jacket when the engine is stopped, so if antifreeze is used as the refrigerant, the antifreeze in the auxiliary tank The concentration does not decrease, and freezing can be reliably prevented.

[Brief explanation of the drawing]

The figure is a configuration diagram showing an embodiment of the present invention. 2...Water jacket, 3...Condenser, 5...Steam passage, 8...Refrigerant passage, 13...
Auxiliary tank, 14...Discharge passage, 17...Opening valve, 27...Pump, 28...Shutoff valve, 29...
Return passage, 32... supply passage, 35... control circuit.

Claims (1)

[Scope of utility model registration request] A closed circuit in which the engine water jacket, which is mostly filled with liquid-phase refrigerant, and the condenser, which maintains the interior in the vapor phase, are connected through a vapor passage through which refrigerant vapor flows and a refrigerant passage where liquefied refrigerant is returned, and the refrigerant circulates. In the evaporative cooling system for an internal combustion engine, the auxiliary tank stores a predetermined amount of liquid phase refrigerant, and the discharge passage connects to the closed circuit at a portion above the refrigerant liquid level in the water jacket. A pump is provided, and the discharge passage is opened into the liquid in the auxiliary tank via a release valve, and a pump is provided to send the liquid phase refrigerant in the water jacket to the auxiliary tank, and a pump to supply the liquid phase refrigerant in the auxiliary tank through a cutoff valve. What is claimed is: 1. A boiling cooling device for an internal combustion engine, comprising: a return path for returning water to a water jacket; and control means for temporarily driving a pump and opening a shutoff valve when the engine is stopped.