JP5834896B2 - Cooling system - Google Patents

Description

  The present specification discloses a cooling device in which a coolant circulates. In particular, a cooling device having a function of discharging the gas confined in the circulation path from the circulation path using the flow of the coolant when the gas is confined in the circulation path of the coolant is disclosed.

2. Description of the Related Art A cooling device is known in which a circulation path around a heating element and a radiator is provided and a cooling liquid is circulated by a pump. The cooling liquid removes heat from the heating element to cool the heating element, and dissipates heat from the radiator to cool the cooling liquid.
In the case of the above cooling device, a phenomenon (gas retention phenomenon) in which gas is confined in the circulation path may occur. For example, a circulation path for cooling an inverter, a converter, a transaxle, etc. of a hybrid vehicle extends as it moves up and down in a complicated manner as disclosed in Patent Document 1, and a gas stagnation phenomenon is likely to occur. The technique of Patent Document 1 discloses a technique that does not cause a gas retention phenomenon by improving the shape of the flow path. In the technique of Patent Document 1, the flow shape of the cooling liquid is generated by discharging the gas confined in the circulation path out of the circulation path by improving the shape of the flow path.

  If the coolant is low temperature, cool the heating element well. Even if the flow rate of the coolant is reduced, the necessary cooling capacity can be secured. Also, the pump that circulates the coolant consumes energy. Therefore, the technique of Patent Document 2 has been proposed. In the technique of Patent Document 2, if the coolant is low temperature, the pump rotation speed is decreased. According to this technique, it is possible to ensure a necessary cooling capacity while suppressing energy consumption by the pump.

  Patent Document 3 discloses a pump control technique for eliminating the gas retention phenomenon. In this technique, the pump speed is decreased while the coolant is low, and the pump speed is increased when the coolant is high. According to this technique, a state in which the coolant is circulated at a low speed and a state in which the coolant is circulated at a high speed can be obtained until the coolant is heated. During this time, the gas trapped in the circulation path is discharged out of the circulation path.

JP 2005-158875 A JP 2008-215094 A JP 2008-180160 A

The technique of Patent Document 2 is an excellent technique for ensuring the necessary cooling capacity while suppressing the energy consumption by the pump, but a problem arises when a gas retention phenomenon occurs. The gas retention phenomenon tends to occur immediately after the replacement of the coolant. That is, it is likely to occur at a low temperature when the coolant is not heated. In the technology of Patent Document 2, in order to suppress the energy consumption by the pump while ensuring the necessary cooling capacity,
When the temperature of the coolant is low, the pump speed is decreased. In order to reduce the pump speed, the flow rate of the coolant is reduced. Therefore, if the gas retention phenomenon has occurred, the retention gas cannot be extruded using the flow of the coolant. Even if the shape of the flow path in which gas is easily discharged using the technique described in Patent Document 1, the staying gas cannot be discharged out of the circulation path in order to reduce the pump rotation speed.
In the technique of Patent Document 3, the gas retention phenomenon is eliminated before the coolant is heated. The gas retention phenomenon cannot be eliminated while the cooling liquid is at a low temperature. Due to the gas retention phenomenon, the cooling efficiency of a specific heating element is reduced, and the heating element may be abnormally heated before the coolant is heated. Such a problem cannot be dealt with by the technique of Patent Document 3.
In the present specification, a technique is disclosed that achieves both suppression of energy consumption by a pump and rapid elimination of a stagnant gas by using a coolant flow to quickly eliminate a gas stagnating phenomenon.

In this specification, a circulation path around the heating element and the radiator, a pump that circulates the coolant in the circulation path, a reserve tank that is connected in the middle of the circulation path, and a temperature detection device that detects the coolant temperature, An apparatus for monitoring whether or not the occurrence probability of a gas retention phenomenon in which gas is retained in the circulation path is high and a cooling apparatus including a pump control device are disclosed.
The pump control device includes a first control procedure for lowering the pump speed when the coolant temperature is low and increasing the pump speed when the coolant temperature is high, and a second control procedure for increasing the pump speed. In addition, the first control procedure is adopted while a state with a high probability of occurrence of a gas stagnation phenomenon is not monitored, and a second control procedure is adopted while a state with a high probability of occurrence of a stagnation phenomenon is being monitored. Execute. When the second control procedure is adopted, even if the coolant is low temperature and highly viscous, a pump that gives a flow rate of discharging the gas staying in the circulation path onto the coolant level stored in the reserve tank Increase to rpm.

According to the above cooling device, while the gas stagnation phenomenon does not occur, the first control procedure is adopted in which the pump rotational speed is decreased when the coolant temperature is low and the pump rotational speed is increased when the coolant temperature is high. Energy consumption by the pump can be suppressed while ensuring the necessary cooling capacity. However, if the probability that the gas retention phenomenon occurs is high, the second control procedure for increasing the pump rotational speed is adopted . The flow rate of the cooling liquid increases as the pump speed increases, and the gas staying in the circulation path can be discharged out of the circulation path due to the increased flow rate. At this time, even if the coolant is low temperature and highly viscous, the pump rotation speed is increased to give a flow rate at which the gas staying in the circulation path is discharged out of the circulation path. As a result, even if the coolant is low temperature and highly viscous, the gas retention phenomenon can be quickly eliminated. The gas stagnation phenomenon can be eliminated without waiting for the coolant to be heated.

  According to the cooling device disclosed in the present specification, the energy consumption by the pump can be suppressed while ensuring the necessary cooling capacity, and when the gas stagnation phenomenon occurs, the gas stagnation phenomenon can be quickly eliminated. It is possible to achieve both the suppression of the energy consumption of the pump and the rapid elimination of the gas stagnation phenomenon using the flow of the coolant.

The figure which shows the circulation path | route of an Example. The figure which shows the heat generating body and heat radiator which the circulation path of an Example circulates. The figure which shows a mode that cooling capacity falls by a gas retention phenomenon and a gas retention phenomenon. The figure which shows the relationship between cooling water temperature and pump rotation speed. The figure which shows 1st Example of the control procedure which a pump control apparatus performs. The figure which shows 2nd Example of the control procedure which a pump control apparatus performs. The figure which shows 3rd Example of the control procedure which a pump control apparatus performs.

The main features of the embodiments described below are listed. Each of the following features has technical usefulness and is a useful technology even if it is not combined with other features.
Feature 1: The pump speed used in the second control procedure is sufficient to discharge the gas staying in the circulation path out of the circulation path when the coolant is low temperature and highly viscous. Is the pump speed. Since the pump speed is increased, the gas retention phenomenon is eliminated.
Feature 2: A reserve tank with a cap is provided in the circulation path, and when the cap is opened, it is determined that there is a high probability that a gas retention phenomenon has occurred, and the second control procedure is switched to.
Feature 3: The cooling device cools electric equipment for traveling of an electric vehicle, a hybrid vehicle, or a fuel cell vehicle.
Feature 4: In the feature 3, if the hood of the automobile is open, it is determined that the probability that the gas retention phenomenon has occurred is high, and the process is switched to the second control procedure.
Characteristic 5: When the temperature of the heating element cooled by the coolant exceeds the appropriate temperature range, it is determined that the probability that the gas retention phenomenon has occurred is high, and the process is switched to the second control procedure.

Example 1
As shown in FIGS. 1 and 2, the cooling device according to the first embodiment includes a radiator 2, an inverter, a converter 4, a reserve tank 6, a pump 8, and a circulation path 12 that goes around the transaxle 10. The inverter, the converter 4 and the transaxle 10 are electric devices for running a car and are heating elements. The radiator 2 is a heat radiator. When the pump 8 is activated, the coolant circulates through the circulation path 12. The coolant is an antifreeze and increases in viscosity at low temperatures.

FIG. 3 schematically shows a part of the circulation path 12 and extends while moving up and down as shown in FIG. The gas 24 (mainly air) is easily trapped in the upwardly curved portion 22. A gas retention phenomenon is likely to occur in the upper curved portion 22.
If a gas stagnation phenomenon occurs in a portion where the circulation path 12 and the heating element 26 are in contact with each other, a heat exchange phenomenon between the heating element 26 and the cooling liquid is reduced, and the ability to cool the heating element 26 is reduced. Rises above the proper temperature. If a gas retention phenomenon occurs, it must be resolved.

The pump 8 is controlled by a pump control device 14. A device 16 for detecting the temperature of the coolant is attached to the circulation path 12, and the detected value is input to the pump control device 14.
The pump control device 14 stores the first control procedure, and controls the pump rotation speed according to the graph 42 in FIG. 4 while the first control procedure is selected. The graph 42 is set in such a relationship that the pump rotational speed is decreased when the coolant temperature is low and the pump rotational speed is increased when the coolant temperature is high. The illustrated T 1 is the lowest temperature assumed for the coolant, and R 1 is the lowest rotation speed of the pump 8. T3 is the highest temperature assumed for the coolant, and R3 is the highest rotational speed of the pump 8. When the pump control device 14 employs the first control procedure, the energy consumption by the pump 8 can be suppressed while ensuring the necessary cooling capacity. The technique described in Patent Document 2 can be diverted to the first control procedure. Although the graph 42 is linear, a step-like relationship may be used or a curve graph may be used.
The pump control device 14 stores the second control procedure. When the gas retention phenomenon occurs, the pump controller 14 increases the rotational speed of the pump 8 to the maximum rotational speed R3 as indicated by the arrow 40 regardless of the coolant temperature. As a result, the gas staying in the circulation path is pushed away by the flow of the cooling liquid and floats on the liquid level in the reserve tank 6. As a result, gas is discharged from the circulation path.

  In FIG. 4, the coolant temperature T2 and the pump rotational speed R2 indicate the limits at which gas can be discharged from the circulation path. If the coolant temperature is T2 or higher and the pump speed is R2 or higher, the gas can be discharged from the circulation path. The coolant is highly viscous at low temperatures, and if the coolant temperature is equal to or lower than T2, even if the pump rotational speed is R2, a flow velocity that pushes gas by the coolant cannot be obtained. Therefore, in the second control procedure that is executed when the gas retention phenomenon occurs, the pump rotational speed is increased to the maximum rotational speed R3. When the pump rotational speed is increased to the maximum rotational speed R3, even if the cooling liquid is low temperature and highly viscous, a flow velocity at which gas is pushed by the cooling liquid can be obtained.

  Even if the second control procedure is not prepared, that is, the control is performed only by the first control procedure, the coolant temperature rises to T2 or higher and the pump rotation speed is R2 or higher while driving the automobile. Thus, a state in which the gas is extruded by the flow of the coolant is obtained. The technique of Patent Document 3 uses that principle. However, in the meantime, there may be a problem that the heating element 26 is overheated due to, for example, the phenomenon shown in FIG. A technique is useful in which a state in which the occurrence probability of the gas stagnation phenomenon is high is monitored, and when a state in which the gas stagnation phenomenon is high in occurrence occurs, the operation is switched to the second control procedure and the operation is performed to discharge the gas from the circulation path.

The gas retention phenomenon tends to occur immediately after the coolant in the circulation path is replaced. In the trial operation stage immediately after the replacement of the coolant, a gas stagnation phenomenon often occurs. Therefore, the control procedure of FIG. The process of FIG. 5 is repeatedly executed at short time intervals.
In step S2, it is determined whether the coolant temperature is equal to or lower than T2. If the coolant temperature is equal to or higher than T2, the viscosity of the coolant is low and the pump rotation speed is adjusted to R2 or higher, so that it can be determined that the gas is discharged. That is, the probability of occurrence of a gas retention phenomenon is low. In this case, the pump rotation speed is controlled in step S8 according to the first control procedure. In the first control procedure, the coolant temperature is detected, the pump rotational speed at the coolant temperature detected from the graph 42 (mapped and stored) in FIG. 4 is specified, and the pump 8 is operated at the rotational speed. drive. By the first control procedure in step S8, control is realized that lowers the pump speed when the coolant temperature is low and increases the pump speed when the coolant temperature is high.

If it is determined in step S2 that the coolant temperature is equal to or lower than T2, the first control procedure cannot eliminate the gas retention phenomenon. Therefore, step S4 is executed to determine whether the gas retention phenomenon has occurred and the possibility is high. In this embodiment, it is determined whether or not the cap of the reserve tank 6 is opened. If the cap of the reserve tank 6 is opened, it is determined that the test operation is performed immediately after the replacement of the coolant, and that the gas retention phenomenon is likely to occur. If so, the pump speed is increased to the maximum speed R3 in step S6. If it is determined in step S4 that a gas retention phenomenon has occurred and the possibility is high, the first control procedure in step S8 is switched to the second control procedure in step S6, and the pump rotation speed is increased regardless of the coolant temperature. . If the cap of the reserve tank 6 is closed in step S4, it is determined that the occurrence probability of the gas retention phenomenon is low, and the first control procedure shown in step S8 is executed.
According to the processing procedure of FIG. 5, the probability of occurrence of the gas retention phenomenon is monitored in step S4, and if the possibility is low, the first control procedure is adopted, and if the possibility is high, the control procedure for switching to the second control procedure is executed. The The pump control device 14 that executes step S4 constitutes a device that monitors whether or not the occurrence probability of the gas retention phenomenon is high. The pump control device 14 that executes steps S6 and S8 causes the gas retention phenomenon to occur. While the state where the occurrence probability is high is not monitored, the first control procedure is adopted, and the apparatus is configured to execute the control procedure for switching to the second control procedure when the state where the gas retention phenomenon is high is monitored.

FIG. 6 shows a second embodiment for discriminating the level of occurrence probability of the gas retention phenomenon. Step S4A is adopted instead of step S4 in FIG. In this embodiment, the pump is operated by opening the hood of the automobile, and it is determined that the possibility of gas stagnation is high due to a trial operation immediately after the replacement of the coolant.
FIG. 7 shows a third embodiment for discriminating the level of occurrence probability of the gas retention phenomenon. Step S4B is adopted instead of step S4 in FIG. In this embodiment, the temperature of a heating element such as an inverter, converter or transaxle is monitored, and if any of the temperatures exceeds an appropriate temperature, the state schematically shown in FIG. It is determined that the cooling capacity has decreased.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. For example, there are various methods other than those described in the embodiments for determining the level of occurrence probability of the gas retention phenomenon.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2: Radiator (heat radiator)
4: Inverter, converter (heating element)
6: Reserve tank 8: Pump 10: Transaxle (heating element)
12: Circulation path 14: Pump control device 16: Coolant temperature detection device

Claims (1)

A circulation path around the heating element and the radiator,
A pump for circulating the coolant in the circulation path;
A reserve tank connected in the middle of the circulation path;
A temperature detection device for detecting the coolant temperature;
A device for monitoring whether or not the occurrence probability of a gas retention phenomenon in which gas is retained in the circulation path is high;
A first control procedure for lowering the pump speed when the coolant temperature is low and increasing the pump speed when the coolant temperature is high, and gas that remains in the circulation path even if the coolant is low temperature and high viscosity Is provided with a second control procedure for increasing the pump rotational speed to give the flow rate of the coolant stored in the reserve tank to the level of the coolant , while the high probability of gas stagnation is not monitored. A pump control device that employs one control procedure and executes a control procedure that employs the second control procedure while a state with a high probability of occurrence of a gas retention phenomenon is being monitored;
Equipped with a cooling device.

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