JPH0248663Y2 - - 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 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 engine operating conditions.

On the other hand, Utility Model Application Publication No. 57-18714 and others have proposed a cooling device that utilizes the latent heat of vaporization of water to cool the engine with a small amount of circulating water. This system uses 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. Because the structure is such that the circulation path is connected to the atmosphere to avoid pressure fluctuations, the boiling point of the cooling water cannot be changed, and it is difficult to perform variable temperature control depending on engine operating conditions. Ta.

Therefore, a closed cooling circuit is constructed by connecting a water jacket that stores liquid phase refrigerant (cooling water) and a condenser that cools the refrigerant vapor generated in this water jacket in a sealed manner to the outside. death,
A boiling cooling device has been proposed that can arbitrarily and rapidly change the boiling point of a liquid phase refrigerant by variable control of the pressure inside the water jacket, thereby achieving highly responsive temperature control according to operating conditions (patent application). Showa 58
−145467, etc.)

(Problem that the invention aims to solve) By the way, with this kind of cooling system, the engine can be cooled with a small amount of coolant, so the water jacket and condenser can be made smaller, making the cooling system smaller and lighter. This has the advantage that the engine warm-up time can be shortened.

However, in this case, even if the warm-up time could be shortened, a considerable amount of warm-up time was still required because the coolant in the water jacket was warmed up while being warmed up.

This invention was made with attention to such problems, and the purpose is to further shorten the warm-up time.

(Means for solving the problem) Therefore, this invention connects the engine water jacket, which is mostly filled with liquid phase refrigerant, and the condenser, which maintains the interior in a vapor phase state, to a vapor passageway through which the refrigerant vapor flows from the upper part. In a boiling cooling system for an internal combustion engine, the system is connected to a refrigerant passage that returns liquefied refrigerant from a condenser via a supply pump to form a closed circuit in which refrigerant circulates, and is equipped with a cooling fan that supplies forced cooling air to the condenser. In addition to providing an auxiliary tank that communicates with the engine water jacket through a passage with a solenoid valve and an electric pump interposed in the middle, a means for detecting the engine operating state and a means for detecting the liquid phase refrigerant in the water jacket when the engine is started are provided. Means for controlling the drive of the electromagnetic valve and the electric pump, respectively, is provided so that the electromagnetic valve and the electric pump are drawn into the auxiliary tank.

(Function) Therefore, when the engine is started, the liquid phase refrigerant in the water jacket is drawn out to the auxiliary tank via the solenoid valve and the electric pump, so the engine temperature rises quickly and the engine temperature increases. teeth,
It also reduces the amount of white smoke and odors generated.

(Example) Figure 1 shows an example of the boiling cooling device according to this invention. First, the basic structure will be explained.
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 the water jacket 2, and 4 is the liquefied refrigerant from the condenser 3. a lower tank for storing refrigerant, 5 a supply pump for returning the stored refrigerant in the lower tank 4 to the water jacket 2;
A cooling fan 6 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;
The liquid level sensor 11 provided in the steam passage 7 and the temperature sensor 12 provided in the steam passage 7 form a control system 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 guide is such that the inside of the condenser 3 is in the gas phase while the refrigerant is secured to the predetermined liquid level in the water jacket 2 as described above. It is set to the extent that it is in the 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 determines the operating state of the engine by detecting the actual temperature detected by the temperature sensor 12 through well-known sensors such as engine rotation and fuel supply amount, and determines the operating state of the engine based on the comparison with the actual temperature. The cooling fan 6 is controlled to operate or stop 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. Since 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.

In this way, the amount of heat dissipation can be quickly controlled according to the operating state of the engine, and the engine can therefore always be operated under optimal temperature conditions, thereby improving fuel efficiency and increasing output.

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 liquid phase refrigerant in the reservoir tank 13 provided outside.

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

This reservoir tank 13 has a solenoid valve 14 in the middle.
It communicates with the lower tank 4 through an auxiliary passage 15 interposed therebetween.

When the solenoid valve 14 is opened based on the detection of the differential pressure sensor 9 after the engine is stopped, the refrigerant stored in the reservoir 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 is pushed back to the auxiliary passage 15 and the reservoir tank 13 by the pressure of the refrigerant vapor that has been boiled and vaporized by the heat of combustion. Since the amount of refrigerant liquid 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 the liquid level thereof decreases. When the inside of the capacitor 3 eventually becomes a gas phase, the electromagnetic valve 14 closes based on a signal from the liquid level sensor 16 that detects this from the liquid level in the lower tank 4, and thereafter the boiling cooling described above is performed.

In addition, in this device, in order to eliminate air intrusion into the system, the reservoir tank 13 and the refrigerant passage 8 are made to communicate via the second auxiliary passage 17, such as immediately after starting the engine. Then, the suction side of the supply pump 5 is switched from the lower tank 4 side to the auxiliary passage 17 via the three-way solenoid valve 18, and the supply pump 5 is driven to pump the refrigerant in the reservoir tank 13 to the water jacket 2. At this time, the top of the cooling system circuit is connected to the reservoir tank 13.
Solenoid valve 2 of passage 19 communicating with the inside (atmospheric pressure) of
0 to vent 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 reservoir tank 13 is
of the stored refrigerant is introduced into the condenser 3 to reduce the heat dissipation area of the condenser 3.

This prevents overcooling of the engine 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 vapor is discharged from the lower tank 4 to the reservoir 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 reservoir tank 13, the amount lost to the atmosphere is extremely small.

In such an evaporative cooling system, the reservoir tank 13 is connected to the engine water via a refrigerant recovery passage 33 which is provided with a solenoid valve 30, an electric pump 31 (which outputs a pump load signal), and a flow rate control valve 32. It is communicated with the jacket 2.

In this case, the water jacket side opening 33a of the refrigerant recovery passage 33 is used when returning the liquid phase refrigerant extracted to the reservoir tank 13, as will be described later.
In order to prevent the cylinder wall from being rapidly cooled by the refrigerant flowing into the water jacket 2, it is set at a position lower than the combustion chamber at the bottom dead center of the piston (low-temperature area within the water jacket 2), as shown in Figure 2. be done.

In addition to the various sensors described above, the control system is also provided with a temperature sensor 35 (wall temperature sensor) that detects the cylinder wall temperature.

Based on the cylinder wall temperature signal, the control circuit 10 controls the solenoid valve 30, the electric pump 31, and the flow control valve so as to temporarily drain the liquid phase refrigerant in the water jacket 2 into the reservoir tank 13 during warm-up operation. 32 etc. is controlled.

Specifically, when the start of warm-up operation is detected, the solenoid valve 20 is opened to release the inside of the cooling system to atmospheric pressure, and at the same time, the solenoid valve 30 is opened and the electric pump 31 is driven to drain the inside of the water jacket 2. liquid phase refrigerant is pumped into the reservoir tank 13.

When the liquid level in the water jacket 2 drops to the passage opening 33a and the pump load on the electric pump 31 drops rapidly, the electric pump 31 is stopped and the solenoid valve 30 is closed. In this state, since the inside of the water jacket 2 is almost empty, the temperature of the cylinder wall rapidly rises due to the heat of combustion. When the cylinder wall temperature reaches a set value, for example 80 degrees Celsius or higher, the solenoid valve 30 is opened and the electric pump 31 is driven (rotating in the opposite direction to when removing the refrigerant) to transfer the refrigerant in the reservoir tank 13 to the water jacket 2. return.
At this time, the control circuit 10 adjusts the flow rate of the refrigerant flowing through the refrigerant recovery passage 33 via the flow rate control valve 32 according to the cylinder wall temperature.

When the liquid level in the water jacket 2 reaches a predetermined level, the electromagnetic valve 30 is closed and the electric pump 31 is stopped based on the detection by the liquid level sensor 11. Next, as described above, the solenoid valve 18 of the auxiliary passage 17 is opened, and the supply pump 5 is driven to forcefully feed the refrigerant stored in the reservoir tank 13 to the water jacket 2, thereby discharging the air in the cooling system through the solenoid valve. 2
0 to the reservoir tank 13 side,
Shifts to normal boiling cooling control.

Note that this air purge action can also be performed using the electric pump 31 as is.

In this way, the liquid phase refrigerant in the water jacket 2 is temporarily drained into the reservoir tank 13 during warm-up (in other words, the inside of the water jacket 2 is almost empty), which is different from the conventional method. The engine temperature rises more quickly than in the case where the engine temperature rises, the warm-up time can be significantly shortened, and the white smoke concentration also decreases rapidly, as shown in FIG. 3, for example.

(Effects of the invention) In summary, according to this invention, the liquid phase refrigerant in the engine water jacket is temporarily drained into the auxiliary tank during warm-up operation, which has the effect of significantly improving the warm-up performance. can get.

[Brief explanation of the drawing]

FIG. 1 is a structural sectional view showing this embodiment, FIG. 2 is a partially enlarged sectional view thereof, and FIG. 3 is a white smoke density characteristic diagram. 2...Water jacket, 3...Condenser, 5...Supply pump, 6...Cooling fan, 7...
...Steam passage, 8...Refrigerant passage, 10...Control circuit, 30...Solenoid valve, 31...Electric pump, 33
...Refrigerant recovery passage.

Claims (1)

[Scope of utility model registration request] 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 to a vapor passage through which the refrigerant vapor flows in the upper part, and a refrigerant passage, which returns the liquefied refrigerant from the condenser via a supply pump. to form a closed circuit in which refrigerant circulates,
In a boiling cooling system for an internal combustion engine that is equipped with a cooling fan that supplies forced cooling air to a condenser, an auxiliary tank is provided that communicates with the engine water jacket through a passage that includes a solenoid valve and an electric pump, and It is characterized by being provided with means for detecting the engine operating state, and means for controlling the drive of the electromagnetic valve and the electric pump, respectively, so that the liquid phase refrigerant in the water jacket is drained into the auxiliary tank when the engine is started. Boiling cooling system for internal combustion engines.