JPH0346175Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is a vehicle equipped with an automatic transmission and a boiling cooling device that cools the engine based on boiling vaporization of liquid phase refrigerant. Regarding the oil cooler.

(Prior Art) A water-cooled cooling system that circulates cooling water between an engine water jacket and a radiator is difficult to satisfy the required amount of heat radiation due to efficiency and dimensional limitations of the radiator and heat capacity of water. It is necessary to circulate a large amount of cooling water, which causes a large drive loss in the water pump, and it is difficult to variably control the cooling water to an appropriate temperature depending on the engine operating state.

On the other hand, Japanese Patent Publication No. 57-57608 and U.S. Pat. No. 4,367,699 propose a cooling system that utilizes the latent heat of vaporization of water to cool an engine with a small amount of circulating water. These systems perform cooling using a cycle in which the cooling water stored in the water jacket is boiled using the heat generated by the engine, and the generated steam is liquefied in a radiator and returned to the water jacket. Since the structure is such that the path through which water vapor flows communicates with the atmosphere to avoid pressure fluctuations, there are maintenance problems such as easy cooling water consumption, and the engine temperature is close to the boiling point of the cooling water at atmospheric pressure. Since it is fixed, there is a problem that it is difficult to apply it to automobile engines and the like where the required amount of heat radiation fluctuates widely.

In response, the present applicant has proposed, in Japanese Patent Application No. 58-145467, etc., that a liquid-phase refrigerant is sealed in a closed-loop cooling circuit, and that the boiling point is controlled by changing the pressure, depending on the engine operating state. We are proposing a boiling cooling system that can perform efficient cooling.

To explain this using Figure 4, in the figure 1
is the engine (main body), 2 is a water jacket filled mostly with liquid phase refrigerant such as water, 3 is a condenser that cools and liquefies the refrigerant vapor from water jacket 2, and 4 is a storage for the liquefied refrigerant from condenser 3. 5 is a supply pump that returns the refrigerant stored in the lower tank 4 to the water jacket 2;
is a cooling fan that supplies forced cooling air to the condenser 3.

The water jacket 2 is attached to the cylinder block 1 so as to surround the cylinders and combustion chambers of the engine 1.
a and cylinder head 1b, and a predetermined amount of liquid phase refrigerant is sealed inside.
The upper part of the water jacket 2 is a gas phase space filled with refrigerant vapor, and in a multi-cylinder engine, the gas phase space is communicated with each other between cylinder sections.

The water jacket 2 communicates with the condenser inlet via a steam passage 7 connected facing the gas phase space.

The lower tank 4 of the condenser 3 communicates with the water jacket 2 via a refrigerant passage 8, forming a closed circuit in which refrigerant circulates between the water jacket 2 and the condenser 3.

In the case of an automobile, the condenser 3 is installed in a position where the wind flows through the vehicle, and the cooling fan 6 is positioned on the front or rear side of the vehicle to supply forced cooling air to the condenser 3. The supply pump 5 is located in the middle of the refrigerant passage 8, and pumps the liquid phase refrigerant accumulated in the lower tank 4 to the water jacket 2 based on a command from a control system to be described later. Note that both the cooling fan 6 and the supply pump 5 are electric.

10 is a control circuit that controls the operation of the supply pump 5 and the cooling fan 6;
Similarly to the liquid level sensor 11 and temperature sensor 12 provided in the engine, a control system is formed together with the differential pressure sensor 9 and other means (not shown) for detecting the engine operating state.

The liquid level sensor 11 is a type of switch whose output changes on and off depending on the position of the refrigerant liquid level with respect to its detection section. Based on this change in output, the control circuit 10 drives the supply pump 5 when the refrigerant liquid level falls below a predetermined value depending on the position of the liquid level sensor 11, and operates the lower tank until the refrigerant level reaches the predetermined level again. 4. Replenish the water jacket 2 with the stored refrigerant. For this reason, water jacket 2
A predetermined amount or more of refrigerant liquid is always ensured. Note that the amount (standard amount) of liquid phase refrigerant sealed in this cooling system is determined when the inside of the condenser 3 is air-filled while the refrigerant is secured to the predetermined liquid level in the water jacket 2 as described above. It is set to such a degree that it is in a phase state.

The temperature sensor 12 detects the engine temperature from the temperature or pressure of the refrigerant, and provides an output corresponding to the engine temperature to the control circuit 10 as an actual temperature signal.

The control circuit 10 detects the actual temperature detected by the temperature sensor 12 as well as engine rotation, throttle opening, fuel supply amount, etc. through well-known sensors, determines the operating state of the engine, and determines the actual temperature. Based on the comparison, the operation or stop of the cooling fan 6 is controlled so that the engine temperature reaches a predetermined temperature depending on the operating state at that time.

It goes without saying that the relationship between the engine operating state and the control temperature value can be set freely depending on the engine specifications, purpose, and application, but in general, automobile engines are operated at low loads or rotational speeds, such as when driving around town. Maintains a relatively high temperature in the operating range,
The temperature should be lowered in the high-speed, high-load range.

To explain the basic function of the cooling system based on the above configuration, when the liquid phase refrigerant in the water jacket 2 is heated by the engine combustion heat, it reaches a boiling point according to the pressure in the system at that time. When the temperature reaches that point, it starts boiling, takes away the latent heat of vaporization, and evaporates.

At this time, the refrigerant boils more actively in the higher temperature parts of the engine 1 and cools the part corresponding to the latent heat of vaporization, so that the combustion chamber and the cylinder wall are kept at a substantially uniform temperature. This makes it possible to raise the temperature of the entire combustion chamber to near the limit temperature that does not cause problems such as abnormal combustion.

The refrigerant vapor generated as a result of the boiling cooling action flows from the gas phase space of the water jacket 2 to the condenser 3 via the vapor passage 7, is cooled by heat exchange with outside air in the condenser 3, condenses and liquefies, and is successively It is stored in the lower tank 4.

In this case, as mentioned above, the inside of the condenser 3 is in a gas phase, and the high temperature refrigerant vapor is in the outside air with a large temperature difference due to good heat transfer between it and the metal surface that constitutes the condenser 3. Because it is cooled, the heat dissipation efficiency is significantly increased compared to when heat is dissipated in the liquid phase. Incidentally, for this reason, the condenser 3 and the cooling fan 6 can be extremely small.

The refrigerant liquefied in the condenser 3 and stored in the lower tank 4 is returned to the water jacket 2 by the operation of the supply pump 5 as the refrigerant level in the water jacket 2 decreases, and by repeating the above steps. Boiling cooling continues.

By the way, in such a closed-circuit boiling cooling device, the pressure inside the system always becomes negative when the engine is stopped. Therefore, as a countermeasure against this negative pressure, the gas phase space within the system is replaced with a liquid phase refrigerant from an auxiliary tank 13 provided outside.

The auxiliary tank 13 stores a liquid phase refrigerant having at least the same capacity as the gas phase space, and atmospheric pressure is introduced into the interior thereof through a cap 13a having a ventilation function.

This auxiliary tank 13 communicates with the lower tank 4 via an auxiliary passage 15 having a solenoid valve 14 interposed therebetween.

When the solenoid valve 14 is opened based on the detection by the differential pressure sensor 9 after the engine is stopped, the refrigerant stored in the auxiliary tank 13 is introduced into the system as the pressure decreases due to the temperature drop, and eventually the space inside the system will be mostly replaced by liquid phase refrigerant.

This reliably prevents harmful air from entering the cooling system when the engine is stopped.

Then, when starting the engine from the above condition,
The liquid phase refrigerant in the system flows through the auxiliary passage 15 and the auxiliary tank 13 due to the pressure of the refrigerant vapor that boils and vaporizes due to the heat of combustion.
being pushed back. Since the amount of refrigerant in the water jacket 2 is maintained at a predetermined value by the replenishment operation of the supply pump 5, only the amount of liquid in the condenser 3 decreases, and its liquid level decreases. Eventually, when the inside of the capacitor 3 becomes a gas phase, the lower tank 4
The liquid level sensor 16 detects this from the liquid level of
The electromagnetic valve 14 closes based on the signal from the oscilloscope, and thereafter the boiling cooling described above is performed.

Additionally, in this device, if air enters the system, the auxiliary tank is
3 and the refrigerant passage 8 through the second auxiliary passage 17, and immediately after starting the engine, etc., the auxiliary passage is switched to the auxiliary passage 17 via the three-way solenoid valve 18, and the supply pump 5 is reversely driven to supply the auxiliary tank 13. The refrigerant is pumped into the water jacket 2. At this time, the solenoid valve 20 of the passage 19 that communicates the top of the cooling system circuit with the inside of the auxiliary tank 13 (atmospheric pressure) is opened to discharge the intruding air.

On the other hand, during cooling operation, if the engine temperature does not reach the set temperature even though the cooling fan 6 is stopped due to the large cooling effect of the running wind, the solenoid valve 14 of the auxiliary passage 15 is opened and the storage in the auxiliary tank 13 is A refrigerant is introduced into the condenser 3 to reduce the heat dissipation area of the condenser 3.

This prevents the engine from overcooling and also prevents air from entering due to negative pressure in the system during operation.

Further, in this device, if the temperature inside the system becomes abnormally high for some reason, the solenoid valve 14 is opened to release the inside of the system to atmospheric pressure.

Therefore, the high pressure steam is discharged from the lower tank 4 to the auxiliary tank 13 together with some liquid phase refrigerant, thereby reducing the pressure in the system and the temperature accordingly. Note that since the discharged vapor is released into the liquid phase refrigerant in the auxiliary tank 13, the amount lost to the atmosphere is extremely small.

As mentioned above, this boiling cooling system can quickly control the amount of heat dissipated according to the operating status of the engine, and therefore the engine can always be operated under optimal temperature conditions, which greatly contributes to improving fuel efficiency and increasing output. Moreover, since the intrusion of air into the cooling system, which adversely affects heat dissipation efficiency, is self-managed by liquid replacement of the refrigerant, it is characterized by extremely high practicality.

(Problem to be solved by the invention) By the way, when a vehicle engine is equipped with the above-mentioned boiling cooling device and an automatic transmission is installed in the power transmission system that transmits the output of the engine to the wheels, automatic transmission In order to prevent the temperature of the oil used in the machine from rising, it is possible to cool the oil by using a liquid phase refrigerant in a boiling cooling device. A system in which a phase refrigerant is introduced has been proposed (Utility Model Application No. 177757/1983).

However, in this case, the liquid phase refrigerant in the lower tank 4 boils in the heat exchanger, and although the latent heat of vaporization provides a high cooling effect of the oil, the temperature of the liquid phase refrigerant in the lower tank 4 becomes high.

For this reason, so-called cavitation tends to occur on the suction side of the supply pump 5 that sends the liquid phase refrigerant in the lower tank 4 to the water jacket 2, resulting in a problem that the liquid phase refrigerant cannot be accurately fed to the water jacket 2. There is.

(Means for solving the problem) This invention is a vehicle in which an automatic transmission is interposed in the engine's power transmission system, and the engine is equipped with the boiling cooling device as described above. In the middle of the refrigerant passage introduced into the jacket or on the side of the water jacket,
A heat exchanger will be installed to cool the automatic transmission oil using liquid phase refrigerant sent from the supply pump.

Further, a steam vent passage is provided which communicates the upper part of the case of the heat exchanger with the gas phase space in the upper part of the water jacket.

(Function) Therefore, the oil for the automatic transmission is efficiently cooled by the liquid phase refrigerant from the supply pump, and at the same time, the oil for the automatic transmission is cooled and liquefied in the condenser on the suction side of the supply pump. Since the phase refrigerant flows in as is, cavitation of the supply pump is prevented and good operation is maintained.

On the other hand, when a portion of the liquid-phase refrigerant heated to high temperature in the heat exchanger evaporates, this refrigerant vapor is introduced from the upper part of the heat exchanger case to the gas-phase space above the water jacket via the steam vent passage. . Therefore, the refrigerant vapor does not mix into the liquid phase portion of the water jacket and deteriorate the cooling efficiency.

(Example) Fig. 1 is a cross-sectional view showing the configuration of an example of the present invention.
21 is a boiling cooling device for the engine 1, and 22 is an automatic transmission interposed in the power transmission system of the engine 1.

The configuration of this evaporative cooling device 21 is the same as that shown in FIG. 4, and the same parts as in FIG. 4 are given the same reference numerals. However, the control circuit is not shown.

A heat exchanger 23 is provided which cools oil such as hydraulic oil used in the automatic transmission 22 using the refrigerant in the boiling cooling device 21.

This heat exchanger 23 is of a so-called multi-plate type, and has a cooling tube 25 of 1 to 3 mm inside the case 24.
The cooling tubes 25 are stacked in three to four layers with gaps between them, and the oil of the automatic transmission 22 is circulated through the cooling tube 25 through an inlet pipe 26 and an outlet pipe 27. Note that the surface of the cooling tube 25 is provided with a large number of unevenness to improve heat exchange.

This heat exchanger 23 is connected to the boiling cooling device 2.
The cooling tube 2 is disposed in the middle of the refrigerant passage 8 between the supply pump 5 of 1 and the water jacket 2.
The supply pump 5 is connected so that the liquid phase refrigerant sent to the water jacket 2 flows through the case 24 in which the water jackets 5 and 5 are stacked.

Additionally, a steam vent passage 2 is provided in the upper part of the heat exchanger 23.
8 is formed, and this steam vent passage 28 is connected to the case 2.
The upper part of the water jacket 4 is connected to the gas phase space at the upper part of the water jacket 2 through an open connection.

Although the refrigerant passage 8 is connected to the water jacket 2 on the cylinder head 1b side, it may be connected to the cylinder block 1a side as in FIG. 4.

With this configuration, refrigerant vapor that boils and evaporates in the water jacket 2 during cooling operation flows into the condenser 3 from the vapor passage 7, where it is cooled and liquefied, and then falls into the lower tank 4. The liquid phase refrigerant inside is sent to the heat exchanger 23 via the refrigerant passage 8 by the supply pump 5.

Therefore, the low-temperature liquid phase refrigerant in the lower tank 4, that is, the refrigerant that does not contain vapor that causes cavitation of the supply pump 5, flows into the suction side of the supply pump 5, so that the supply pump 5 can operate smoothly. It is maintained.

On the other hand, the liquid phase refrigerant sent to the heat exchanger 23 exchanges heat with the oil circulated from the automatic transmission 22 to the cooling tube 25, and a portion of the refrigerant boils and evaporates while absorbing latent heat of vaporization.

This vapor is guided from the vapor vent passage 28 to the gas phase space above the water jacket 2, and the liquid phase refrigerant heated to a high temperature by heat exchange is returned from the refrigerant passage 8 into the liquid phase refrigerant of the water jacket 2. It can be done.

Therefore, the oil from the automatic transmission 22 is efficiently and sufficiently cooled with the addition of a portion of the latent heat of vaporization of the refrigerant. On the other hand, since the refrigerant vapor generated in the heat exchanger 23 is introduced into the gas phase space above the water jacket 2, the vapor phase refrigerant does not mix with the liquid phase refrigerant in the water jacket 2. Good cooling efficiency can also be ensured on the engine body side.

In this way, the oil in the automatic transmission 22 is cooled, and the supply pump 5 can be maintained in good operation to properly circulate the refrigerant, so that the oil for the engine cooling system and the automatic transmission can be cooled. Excellent cooling performance is ensured as a cooler.

Note that the supply pump 5 is not driven as much when the engine load is low, when the amount of refrigerant vapor generated from the water jacket 2 is small, but at this time, the temperature of the oil in the automatic transmission 22 does not rise so much, and the heat exchanger When the refrigerant in the water jacket 23 decreases due to evaporation, the refrigerant in the water jacket 2 flows in and the liquid level in the jacket 2 decreases, and the supply pump 5 is driven accordingly, so that the inside of the heat exchanger 23 is always kept constant. Filled with liquid phase refrigerant.

2 and 3 show another embodiment of the present invention, in which a heat exchanger 29 is attached to the side of the water jacket 2. FIG.

In this case, a communication port 31 is provided between the side surface of the case 30 of the heat exchanger 29 and the side surface of the water jacket 2.
is provided, and the case 30 is fixed to the side surface of the water jacket 2 via a gasket with bolts or the like.

According to this, the arrangement of the heat exchanger 29 is simplified and the space utilization efficiency is improved.

(Effects of the invention) As described above, according to the invention, the heat exchanger for automatic transmission oil is disposed in the middle of the refrigerant passage that introduces the refrigerant from the supply pump into the water jacket or on the side of the water jacket. Therefore, there is no generation of steam that causes cavitation on the suction side of the supply pump, and the refrigerant can be circulated accurately, providing excellent cooling performance as an engine cooling device and an oil cooler for automatic transmissions.

In addition, in this invention, the upper part of the heat exchanger case is communicated with the gas phase space above the water jacket through the steam passage, so that the refrigerant vapor generated in the heat exchanger is mixed with the liquid phase refrigerant in the water jacket. Since the cooling efficiency is prevented from being deteriorated due to the mixing of refrigerant vapor, it is also possible to ensure good cooling performance on the engine body side.

[Brief explanation of the drawing]

Fig. 1 is a structural sectional view showing an embodiment of the present invention, Figs. 2 and 3 are structural sectional views showing other embodiments of the present invention and its view taken along the line A-A, and Fig. 4 is a structural sectional view showing another embodiment of the present invention. FIG. 2 is a cross-sectional view of the configuration of the boiling cooling device of the present invention. 2...Water jacket, 3...Condenser, 5...Supply pump, 6...Cooling fan, 7...
...Steam passage, 8...Refrigerant passage, 13...Auxiliary tank, 22...Automatic transmission, 23...Heat exchanger, 2
8... Steam vent passage, 29... Heat exchanger.

Claims (1)

[Scope of utility model registration request] While an automatic transmission is installed in the power transmission system, the engine water jacket, which is mostly filled with liquid-phase refrigerant, and the condenser, which maintains the interior in a vapor phase, are connected from the vapor passage in the upper part through which refrigerant vapor flows and the condenser. In a vehicle equipped with an evaporative cooling system that is provided with a cooling fan that communicates with a refrigerant passage that returns liquefied refrigerant via a supply pump to form a closed circuit in which the refrigerant circulates and supplies forced cooling air to a condenser, A heat exchanger that cools the oil for the automatic transmission with the liquefied refrigerant from the supply pump is disposed in the middle of the refrigerant passage that introduces the liquefied refrigerant from the pump into the water jacket or on the side of the water jacket, and An oil cooler for a vehicle with an automatic transmission, characterized in that a steam vent passage is provided that communicates the upper part of the case of the heat exchanger with the gas phase space in the upper part of the water jacket.