JP5302068B2 - Boiling cooler - Google Patents

Description

  The present invention relates to a boiling cooling device in which an internal pressure of a pressure regulating chamber provided in an upper portion of a liquid phase refrigerant passage is changed so that a saturation temperature of the liquid phase refrigerant falls within a target saturation temperature range.

  2. Description of the Related Art Conventionally, a boiling cooling device that cools a heating element using heat of vaporization of a refrigerant is known. This boiling cooling device absorbs heat from the heating element using the latent heat of vaporization when the refrigerant evaporates, so it has a higher cooling effect than a general cooling system that circulates the refrigerant in the liquid phase. Can be obtained.

  For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2001-349881), the bottom part of the evaporator and the condenser (condenser) is communicated with a lower communication pipe, and the upper part is communicated with an upper communication pipe. Discloses a technique including a pressure regulating valve. That is, in the technique disclosed in this document, the liquid refrigerant stored in the evaporator absorbs the heat of the heating element and boils, thereby cooling the heating element. Further, the refrigerant (gas phase refrigerant) is boiled and vaporized by the heat absorption from the heating element, passes through the upper communication pipe, flows to the condenser, and is cooled and liquefied there. On the other hand, a cooling water pump is interposed in the lower communication pipe, and the liquid level of the evaporator is controlled to be constant by driving the cooling water pump.

  Furthermore, in this document, the temperature of the heating element is kept substantially constant by adjusting the internal pressure of the evaporator according to the opening degree of the upper communication pipe pressure adjusting valve and varying the boiling point (saturation temperature) of the refrigerant. Yes. That is, when the temperature of the heating element is higher than the target temperature, the pressure regulating valve is opened widely to lower the internal pressure of the evaporator and lower the boiling point, thereby promoting the vaporization of the refrigerant and lowering the temperature of the heating element. On the other hand, when the temperature of the heating element is lower than the target temperature, the pressure regulating valve is throttled to increase the internal pressure of the evaporator and raise the boiling point, thereby suppressing the vaporization of the refrigerant and raising the temperature of the heating element.

  In the technique disclosed in the above-mentioned document, the saturation temperature of the refrigerant is varied by controlling the flow rate of the vaporized refrigerant in the upper communication pipe communicating with the upper part of the evaporator and the condenser by the pressure regulating valve, thereby generating heat. I try to keep my body temperature constant.

  However, the flow of the gas-phase refrigerant is only performed by the differential pressure between the evaporator and the condenser. For example, when the heat generation amount of the heating element is small and the target temperature is low, the gas-phase refrigerant flowing through the upper communication pipe Since the flow rate is small, the internal pressure of the evaporator cannot be lowered greatly even if the pressure regulating valve is opened, and it becomes difficult to control the temperature of the heating element.

  In view of the above circumstances, the present invention is capable of cooling a heating element within a predetermined temperature range even if the heating value of the heating element is small and the target temperature for keeping the temperature of the heating element within a certain range is set low. An object of the present invention is to provide a boiling cooling device that can be used.

In order to achieve the above object, the present invention provides a liquid-phase refrigerant passage through which a liquid-phase refrigerant for cooling a heating element flows, and a gas-phase refrigerant generated by boiling in the liquid-phase refrigerant passage to the liquid-phase refrigerant passage. And a refrigerant recirculation passage that forms a closed circulation path that communicates with the liquid phase refrigerant passage, a pressure adjusting chamber that is provided in an upper portion of the liquid phase refrigerant passage and retains the liquid phase refrigerant, and A non-return means provided in the gas phase refrigerant passage communicating with the upper portion of the pressure regulating chamber and allowing only the gas phase refrigerant to flow from the pressure regulating chamber to the gas phase refrigerant passage side; and the liquid phase In a boiling cooling apparatus including a pump unit provided in a refrigerant passage for causing the liquid phase refrigerant to flow and a control unit for controlling the operation of the pump unit, the pump unit passes the liquid phase refrigerant into the liquid phase refrigerant passage. Can flow in both directions and before The control means compares the temperature of the liquid refrigerant stored in the pressure regulating chamber with a preset target saturation temperature, and the pump so that the temperature of the liquid refrigerant falls within the target saturation temperature range. After the unit is driven to reduce the space pressure in the pressure regulating chamber and the temperature of the liquid-phase refrigerant falls within the target saturation temperature range, the liquid level in the pressure regulating chamber and a preset lower limit liquid level When the liquid level is lower than the lower limit liquid level, the temperature of the liquid-phase refrigerant on the opposite side of the pump unit from the pressure regulating chamber of the liquid-phase refrigerant passage and a preset target The pump is compared with a specified temperature, and when the temperature of the liquid phase refrigerant is higher than the target specified temperature, the pump has a high feed rate, and when the temperature of the liquid phase refrigerant is lower than the target specified temperature, the pump has a low feed rate. The liquid level in the pressure regulating chamber was preset by driving the unit. Until limit water level, characterized in that sending the liquid refrigerant.

  According to the present invention, the liquid phase refrigerant is caused to flow by the operation of the pump unit, and the temperature of the liquid phase refrigerant is controlled to converge to a preset saturation temperature. It can be actively controlled. Therefore, even when the heat generation amount of the heat generating element is small and the target temperature for keeping the temperature of the heat generating element within a certain range is set low, the heat generating element can be cooled in the predetermined temperature range.

1 is a schematic configuration diagram of a boiling cooling device according to a first embodiment. The same configuration diagram showing the control system of the boiling cooling device Flowchart showing the cooling water temperature control routine (No. 1) Flowchart showing the cooling water temperature control routine (part 2) The flowchart showing the cooling fan control routine Same as above, time chart showing changes in outside air temperature, cooling water temperature and heating element temperature Schematic configuration diagram of a boiling cooling device according to a second embodiment The operation of the flow path switching valve is shown, (a) is a schematic diagram showing the flow of cooling water when the cooling water pump is rotating forward, and (b) is the schematic showing the flow of cooling water when the cooling water pump is rotating in reverse. Figure The same configuration diagram showing the control system of the boiling cooling device Flowchart showing the cooling water temperature control routine (No. 1) Flowchart showing the cooling water temperature control routine (part 2)

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
1 to 6 show a first embodiment of the present invention. In the present embodiment, a case where the boiling cooling device is mounted on an electric vehicle will be described as an example. In this case, the electric vehicle includes a hybrid electric vehicle and a fuel cell vehicle.

  As shown in FIG. 1, an electric vehicle controls a traveling motor generator 1, electric power supplied to the traveling motor generator 1, or supplies regenerative electric power from the traveling motor generator 1 to a battery 3 to be described later. There are provided an inverter 2, a battery 3 for supplying electric power to the traveling motor generator 1 through the inverter 2, or charging regenerative electric power from the traveling motor generator 1. The traveling motor generator 1 and the inverter 2 are heating elements that generate heat when energized, and the battery 3 is a heating element that generates heat when charging and discharging. These heat generating elements do not have a high heat generation temperature like an engine. Therefore, the cooling temperature is also relatively low at about 50 to 60 [° C.].

  In the present embodiment, the low-temperature heating element, that is, the traveling motor generator 1, the inverter 2, and the battery 3 are cooled by a refrigerant flowing in a closed circulation path provided in the boiling cooling device 11. In the present embodiment, cooling water is used as the refrigerant, but ethanol may be used. In the following, liquid-phase cooling water that is an example of a liquid-phase refrigerant is referred to as “cooling water”, and gas-phase cooling water that is an example of a gas-phase refrigerant is referred to as “water vapor”. Further, the liquid level of the liquid phase refrigerant is referred to as a water level in the cooling water.

  A condenser 12 and a pressure regulating chamber 13 are interposed in the closed circulation path of the boiling cooling device 11. In addition, a lower cooling water passage 14 is provided in the sealed circulation path, one end of the lower cooling water passage 14 communicates with the bottom of the condenser 12, and the other end of the pressure regulating chamber 13. It communicates with the bottom. The pressure adjusting chamber 13 is disposed at a position higher than the heating element, and an electric cooling fan 12a that actively circulates cooling air to the capacitor 12 is provided on the back surface of the capacitor 12. Has been.

  Further, in the closed circulation path, the upper part of the pressure regulating chamber 13 and the upper part of the reservoir chamber 16 are communicated with each other via an upper reflux passage 17, and further, the upper part of the reservoir chamber 16 and the upper part of the condenser 12 are connected to the water vapor reflux passage. 18 to communicate with each other.

  The lower cooling water passage 14 includes a first cooling water passage 14 a that communicates the bottom of the condenser 12 and the upper portion of the lower reservoir chamber 19, a second cooling water passage 14 b that communicates with the bottom of the lower reservoir chamber 19, and the second cooling water passage 14 b. A third cooling water passage 14c and a fourth cooling water passage 14d that are branched and connected to the cooling water passage 14b are provided.

  The third coolant passage 14 c passes through the outer periphery of the traveling motor generator 1 and communicates with the bottom of the pressure regulating chamber 13. The fourth cooling water passage 14 d passes through the outer periphery of the inverter 2 and the battery 3 and communicates with the bottom of the pressure regulating chamber 13. A cooling water pump 20 is interposed in the second cooling water passage 14b. This cooling water pump 20 actively flows cooling water, and is a constant capacity rotary pump that can rotate bidirectionally such as a screw type, a trochoid type, a gear type, etc. The operation of supplying the cooling water to the normal direction is referred to as normal rotation, and the operation of extracting the cooling water from the pressure regulating chamber 13 side is referred to as reverse rotation. The cooling water pump 20 can rotate in both directions, and the cooling water pump 20 alone constitutes the pump unit of the present invention.

  The bottom of the pressure regulating chamber 13 is located higher than the lower cooling water passage 14, and the bottom of the reservoir chamber 16 is disposed above the lower reservoir chamber 19. The bottom of the reservoir chamber 16 and the upper portion of the lower reservoir chamber 19 are communicated with each other via a cooling water recirculation passage 21.

  Further, the pressure regulating chamber 13 includes a water level sensor 22 that measures the water level (liquid level) WL stored in the pressure regulating chamber 13, an internal pressure sensor 23 that detects the upper space internal pressure PT, and a cooling water temperature (upper cooling). A water temperature sensor 24 for detecting (water temperature) TW1 is provided. In the present embodiment, a float type water level gauge is employed as the water level sensor 22.

  Further, a check valve 25 as a check means is provided in the vicinity of the port opened to the pressure regulating chamber 13 of the upper reflux passage 17. The check valve 25 opens when the internal pressure of the pressure adjusting chamber 13 is higher than the internal pressure of the reservoir chamber 16 due to the differential pressure between the pressure adjusting chamber 13 and the reservoir chamber 16, and the water vapor in the pressure adjusting chamber 13 is stored in the reservoir. When the internal pressure of the reservoir chamber 16 is higher than the internal pressure of the pressure regulating chamber 13, the valve is closed and the passage is blocked. Further, a vacuum pulling valve 26 is communicated with the upper reflux passage 17 in the vicinity of the reservoir chamber 16 side. This vacuum pulling valve 26 is normally sealed. When a vacuum pump (not shown) is connected to the vacuum pulling valve 26 and the vacuum pump is operated, the valve is opened and the inside of the boiling cooling device 11 is depressurized. . In addition, a water inlet 27 is provided in the reservoir chamber 16. The water injection port 27 is for injecting cooling water, and the water injection port 27 is sealed with a cap 27a.

  Further, an internal pressure sensor 28 for detecting the internal pressure PA is provided in the reservoir chamber 16. Further, a water temperature sensor 29 for detecting the temperature (lower cooling water temperature) TW2 of the cooling water stored in the lower reservoir chamber 19 is disposed in the lower reservoir chamber 19.

  Parameters detected by these sensors 22, 23, 24, 28, 29 are input to the control device 30 as control means. Further, a cooling water pump 20 and a cooling fan 12 a are connected to the output side of the control device 30.

  The control device 30 is mainly composed of a microcomputer, and a program for controlling the cooling water pump 20 and the cooling fan 12a is stored in the built-in memory based on each input parameter.

  The control device 30 controls the discharge flow rate and rotation direction of the cooling water pump 20 based on the water level WL of the cooling water stored in the pressure adjusting chamber 13 and the space internal pressure PT, and further, the internal pressure PA of the reservoir chamber 16 and the lower reservoir. Based on the temperature (lower cooling water temperature) TW2 of the cooling water stored in the chamber 19, the ON / OFF of the cooling fan 12a and the air volume are controlled so that the temperature of the cooling water falls within a substantially constant range.

  In the control device 30, the cooling water pump 20 is controlled according to the pump drive control routine shown in FIGS. 3 and 4, and the cooling fan 12a is controlled according to the cooling fan control routine shown in FIG.

  By the way, in the factory, cooling water is injected into the boiling cooling device 11 that has been assembled. The cooling water is injected by a specified amount from the water injection port 27 of the reservoir chamber 16, and after the injection is completed, the water injection port 27 is sealed with a cap 27a. While the cooling water is being poured, the cooling water stays between the reservoir chamber 16 and the cooling water pump 20. In the present embodiment, an amount slightly larger than the sum of the volume of the lower cooling water passage 14 and the volume of the lower reservoir chamber 19 is set as the specified amount.

  Next, a vacuum pump (not shown) is attached to the vacuum pulling valve 26 interposed in the upper reflux passage 17 communicating with the reservoir chamber 16 and sucked. Then, not only the internal pressure of the reservoir chamber 16 is reduced, but the check valve 25 provided in the upper reflux passage 17 is opened, and the pressure regulating chamber 13, the second and third cooling water passages 14b and 14c are opened. The internal pressure of is reduced. Then, when evacuation is performed to a specified pressure (for example, 3 to 5 [kPa]) or when a preset evacuation time has elapsed, the evacuation valve 26 is closed to stop evacuation. Next, the cooling water pump 20 is rotated forward for a predetermined time, and the cooling water staying in the lower reservoir chamber 19 is sent to the pressure regulating chamber 13 side through the cooling water passage 14.

  Thereafter, normal operation is performed. In the normal operation, when the traveling motor generator 1 is driven, the traveling motor generator 1 and the heating elements such as the inverter 2 and the battery 3 generate heat. When the heating elements including these traveling motor generators 1 generate heat, the cooling water for cooling them is heated to raise the temperature. And when this cooling water reaches saturation temperature, it boils, and the pressure (water pressure PT) of the water vapor | steam of the upper space of the pressure regulation chamber 13 becomes high gradually. The heat generating temperature of the heating element including the traveling motor generator 1 is relatively low, and in this embodiment, the target cooling temperature for cooling them is set to about 50 to 60 [° C.].

  Next, a control routine for the cooling water pump 20 and a control routine for the cooling fan 12a executed by the control device 30 will be described.

  In the normal operation, when the pump drive control routine shown in FIGS. 3 and 4 is started, first, the water level WL detected by the water level sensor 22 provided in the pressure regulating chamber 13 is read in step S1, and the water level is read in step S2. WL is compared with a preset upper limit water level Hw. This upper limit water level Hw is an allowable value at which cooling water can be poured into the pressure regulating chamber 13 by the cooling water pump 20, and the amount of cooling water injected into the boiling cooling device 11 and the lower reservoir chamber 19 from the cooling water pump 20. It is set based on the minimum remaining amount of the cooling water stored on the side.

  If the water level WL is less than the upper limit water level Hw (WL <Hw), the process proceeds to step S3, the cooling water pump 20 is rotated forward at high speed (H) (high water supply operation), and the process returns to step S1. As a result, the water level WL in the pressure regulating chamber 13 rises at a relatively high speed. When the water level WL in the pressure regulating chamber 13 rises, the pressure in the pressure regulating chamber 13 becomes higher than the pressure in the upper reflux passage 17, so that the check valve 25 is opened and the internal pressure is released. The space internal pressure PT does not increase greatly.

  When the water level WL in the pressure regulating chamber 13 reaches the upper limit water level Hw (WL ≧ Hw), the process proceeds to step S4 and the upper part of the pressure regulating chamber 13 detected by the internal pressure sensor 23 provided in the pressure regulating chamber 13 is reached. Is read, and the process proceeds to step S5.

  In step S5, the internal pressure PT is compared with a preset primary specified pressure Mpt (for example, 10 to 15 [kPa]). If PT> Mpt, that is, if the spatial pressure PT is relatively high immediately after the water level WL reaches the upper limit water level Hw, the process proceeds to step S6. If it progresses to step S6, the cooling water pump 20 will be reversed at high speed (H) (high drainage operation), and it will return to step S4. When the cooling water pump 20 is reversed, the cooling water stored in the pressure regulating chamber 13 is drained, so that the water level WL is lowered and the internal pressure PT becomes lower than the internal pressure of the upper recirculation passage 17. Therefore, the check valve 25 is closed and the upper space of the pressure regulating chamber 13 is in a sealed state. When the water level WL decreases at a high speed while the upper space of the pressure regulating chamber 13 remains sealed, the internal pressure PT decreases at a relatively high speed.

  Then, when the routine of steps S4 to S6 is repeatedly executed and the internal space pressure PT decreases to the primary specified pressure Mpt or less (PT ≦ Mpt), the process proceeds to step S7, and the cooling water pump 20 is reversed at a low speed (L). (Low drainage operation), the process proceeds to step S8. As a result, the water level WL in the pressure adjusting chamber 13 decreases at a relatively high speed until the spatial pressure PT reaches the primary specified pressure Mpt. Therefore, the spatial pressure PT similarly decreases at a relatively high speed. Then, after the spatial pressure PT reaches the primary specified pressure Mpt, the water level WL is slowly lowered, so that the spatial pressure PT is also relatively moderately reduced.

  In step S8, the space internal pressure PT detected by the internal pressure sensor 23 is read, and in step S9, the space internal pressure PT is compared with a preset target specified pressure Lpt (for example, 15 to 20 [kPa]). This target specified pressure Lpt is set based on the saturation temperature. In this embodiment, the saturation temperature is set to about 50 to 60 [° C.].

  If the internal space pressure PT has not decreased to the target specified pressure Lpt, the process returns to step S7, and the routine is repeatedly executed until the internal space pressure PT becomes equal to or lower than the target specified pressure Lpt.

  Thereafter, when the internal pressure PT has decreased to the target specified pressure Lpt or less (PT ≦ Lpt), the process proceeds to step S10. When the space internal pressure PT is equal to or lower than the primary specified pressure Mpt, the coolant water level WL gradually decreases, so that the space internal pressure PT can be accurately reduced to the target specified pressure Lpt. Note that when the pressure in the upper space of the pressure regulating chamber 13 decreases, the saturation temperature of the cooling water decreases.

  Then, when proceeding to step S10, the coolant temperature (upper coolant temperature) TW1 detected by the water temperature sensor 24 and stored in the pressure adjusting chamber 13 is read, and in step S11, the upper coolant temperature TW1 and the target set in advance are read. The target upper specified water temperature Ltw1 (in this embodiment, about 50 to 60 [° C.]) as the saturation temperature is compared. If the upper cooling water temperature TW1 exceeds the target upper specified water temperature Ltw1 (TW1> Ltw1), the process proceeds to step S12, and the cooling water pump 20 continues the low drainage operation to slowly reduce the saturation temperature of the cooling water. And lower.

  On the other hand, if the upper cooling water temperature TW1 is lower than the target upper specified water temperature Ltw1 (TW1 ≦ Ltw1), it is not necessary to lower the saturation temperature of the cooling water, so the process proceeds to step S13, the cooling water pump 20 is stopped, and step S14 is performed. Proceed to Therefore, for example, immediately after starting the electric vehicle, in the state where the temperature of the heating element that is the cooling target of the boiling cooling device 11 such as the traveling motor generator 1, the inverter 2, the battery 3, etc. has not been raised yet, Proceeding to step S13, the cooling water pump 20 is stopped.

  In step S14, the coolant level WL of the cooling chamber 13 detected by the water level sensor 22 is read, and in step S15, the water level WL is compared with a preset lower limit water level Lw. This lower limit water level Lw is an allowable lower limit water level of the cooling water stored in the pressure regulating chamber 13, and is set in advance based on experiments or the like. The cooling water that has absorbed the heat from the heating element is gradually heated, and when it reaches the saturation temperature, it boils and the amount of water vapor generated in the pressure regulating chamber 13 increases. When the amount of water vapor increases, the coolant water level WL relatively decreases. Further, when the amount of water vapor in the pressure adjusting chamber 13 increases, the space internal pressure PT rises, the check valve 25 opens, and water vapor is sent to the reservoir chamber 16.

  Then, the cooling water pump 20 is stopped until the water level WL reaches the lower limit water level Lw. Thereafter, when the water level WL reaches the lower limit water level Lw (WL ≦ Lw), the process proceeds to step S16 in order to cause the cooling water pump 20 to rotate forward to raise the water level WL in the pressure regulating chamber 13.

  In step S16, the coolant temperature (lower coolant temperature) TW2 stored in the lower reservoir chamber 19 detected by the water temperature sensor 29 provided in the lower reservoir chamber 19 is read, and preset in step S17. The target lower specified water temperature Ltw2 (about 50 to 60 [° C.] in the present embodiment) as the target specified temperature is compared.

  When the lower cooling water temperature TW2 is higher than the target lower defined water temperature Ltw2 (TW2> Ltw2), the process returns to step S3, the cooling water pump 20 is operated to perform high water supply operation, and the water level WL in the pressure regulating chamber 13 is set at a relatively high speed. Raise with. On the other hand, when the lower cooling water temperature TW2 is lower than the target lower specified water temperature Ltw2 (TW2 ≦ Ltw2), the process proceeds to step S18, the cooling water pump 20 is rotated forward at a low speed (L) (low water supply operation), and the pressure regulating chamber 13 The water level WL is gradually raised, and the process returns to step S1.

  When the cooling water pump 20 is supplied with water (forward rotation) in step S18 or step S3, the water level WL in the pressure regulating chamber 13 gradually increases. Then, the water vapor filled in the upper space of the pressure regulating chamber 13 opens the check valve 25 as the water level WL rises, and is sent to the reservoir chamber 16 through the upper reflux passage 17. A part of the water vapor sent to the reservoir chamber 16 is converted into a liquid phase and becomes cooling water and stays at the bottom. The cooling water staying at the bottom flows through the cooling water recirculation passage 21 and flows into the lower reservoir chamber 19. On the other hand, a part of the water vapor staying in the reservoir chamber 16 is sent to the condenser 12 via the water vapor recirculation passage 18, where it is cooled and liquidified to become cooling water and stays at the bottom. Then, the cooling water staying at the bottom of the condenser 12 is sent to the lower reservoir 19 through the first cooling water passage 14a.

  The cooling water and the water vapor are circulated by the forward rotation operation (water supply operation) of the cooling water pump 20. That is, when the cooling water pump 20 performs a water supply operation, the cooling water staying in the lower reservoir chamber 19 is sent to the pressure regulating chamber 13 through the second to fourth cooling water passages 14b to 14d. Then, as the water level WL in the pressure regulating chamber 13 rises, water vapor staying in the upper space is sent to the reservoir chamber 16 through the upper reflux passage 17. Then, the water vapor and cooling water staying in the reservoir chamber 16 are sent out to the lower reservoir chamber 19 side by the pressure of the water vapor sent from the pressure regulating chamber 13 and reduced.

  As a result, for example, when the temperature (lower cooling water temperature) TW2 of the cooling water staying in the lower reservoir 19 is higher than the target lower specified water temperature Ltw2, the cooling water is circulated by operating the cooling water pump 20 at a high water supply operation, Since the vaporized cooling water (water vapor) is reduced to a liquid phase, the temperature of the cooling water staying in the lower reservoir chamber 19 can be lowered. In this case, the temperature of the cooling water flowing through the second to fourth cooling water passages 14b to 14d temporarily rises due to the water supply operation of the cooling water pump 20. However, when the water level WL reaches the upper limit water level Hw, the cooling water pump 20 immediately reverses and shifts to the drainage operation, the pressure in the internal space of the pressure regulating chamber 13 is reduced, and the saturation temperature of the cooling water is targeted. Since the temperature is lowered to the upper specified water temperature Ltw1 (for example, 50 to 60 [° C.]), the cooling water temperature does not increase significantly.

  As a result, as shown by a solid line in FIG. 6, the upper cooling water temperature TW1 is set to the target upper specified water temperature Ltw1 that is the target cooling water temperature in the water supply operation, the drainage operation, and the pump stop of the cooling water pump 20. It can be controlled in the saturation temperature range (target saturation temperature range). In this case, for example, when the target specified pressure Lpt is set to about 3 [kPA], it is possible to control the upper cooling water temperature TW1 in a saturation temperature range lower than the outside air temperature.

  By the way, when the internal pressure of the reservoir chamber 16 is high, the amount of water vapor flowing to the condenser 12 also increases. Similarly, if the temperature (lower cooling water temperature) TW2 of the cooling water staying in the lower pool chamber 19 is higher than the target lower specified water temperature Ltw2, the heating element cannot be efficiently cooled. In such a case, the control device 30 controls the cooling fan 12a according to the cooling fan control routine shown in FIG. 5 to cool the water vapor and the cooling water staying in the condenser 12.

  In this routine, first, in step S21, the internal pressure PA of the reservoir chamber 16 detected by the internal pressure sensor 28 is read. In step S22, the internal upper pressure PA and a target upper specified pressure Hpa as a preset target specified pressure Hpa (for example, 8 to 10). [kPa]). When the internal pressure PA is higher than the target upper specified pressure Hpa (PA> Hpa), the process proceeds to step S23, the cooling fan 12a is rotated at a high speed, and the process returns to step S21. When the cooling fan 12a is rotated at a high speed, the amount of cooling air passing through the condenser 12 is increased, the liquid phase of water vapor staying in the condenser 12 is promoted, and the internal pressure PA of the reservoir chamber 16 is lowered.

  If the cooling fan 12a is continuously rotated at a high speed until the internal pressure PA of the reservoir chamber 16 decreases to the target upper specified pressure Hpa, and the internal pressure PA decreases to the target upper specified pressure Hpa (PA ≦ Hpa), step S24. The temperature of the cooling water staying in the lower reservoir chamber 19 (lower cooling water temperature) TW2 is read, and the lower cooling water temperature TW2 is compared with a preset target lower specified water temperature Ltw2 in step S25.

  When the lower cooling water temperature TW2 is higher than the target lower specified water temperature Ltw2 (TW2> Ltw2), the process proceeds to step S26, the cooling fan 12a is rotated at a low speed, and the process returns to step S21. As a result, the vaporization of the cooling water staying in the lower portion of the capacitor 12 is suppressed, and the increase in the internal pressure of the reservoir chamber 16 is suppressed.

  On the other hand, if the lower cooling water temperature TW2 is lower than the target lower specified water temperature Ltw2 (TW2 ≦ Ltw2), the process proceeds to step S27, the cooling fan 12a is stopped, and the process returns to step S21. As a result, the internal pressure PA of the reservoir chamber 16 can be controlled within a certain pressure range with respect to the target upper specified pressure Hpa.

  As described above, in this embodiment, the cooling water for cooling the heating element is circulated by cooling and condensing the water vapor by the forward rotation operation of the cooling water pump 20, and the cooling water pump 20 is reversed. Since the saturation temperature is actively lowered to the target upper specified water temperature Ltw1 (in this embodiment, 50 to 60 [° C.]) by reducing the internal pressure PT, the heat generation amount of the heating element is small. Even if the target temperature for keeping the temperature of the heating element within a certain range is set low, the heating element can be efficiently cooled and the cooling water can be kept within the target saturation temperature range.

[Second Embodiment]
7 to 11 show a second embodiment of the present invention. This embodiment is a modification of the first embodiment described above. In the first embodiment, a constant-capacity bidirectional pump is adopted as the cooling water pump 20, but in this embodiment, a unidirectional pump is adopted, and the cooling water flows on the upstream side and the downstream side of the cooling water pump 20. This is performed by switching the switching valves 31 and 32 arranged in the above. Accordingly, in the present embodiment, the cooling water pump 20 and the two switching valves 31 and 32 constitute the pump unit of the present invention. In addition, about the component same as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 7, the second cooling water passage 14b connected to the lower reservoir chamber 19 is branched into two branches, and the second cooling water passage 14c and the fourth cooling water passage 14d are joined at the joining portion of the third cooling water passage 14c and the fourth cooling water passage 14d. The fifth cooling water passage 14f and the sixth cooling water passage 14g are connected. One end of the second cooling water passage 14 b branched into two branches and the end of the fifth cooling water passage 14 f are connected to the upstream side of the cooling water pump 20 via the upstream switching valve 31. The other end of the second cooling water passage 14 b and the end of the sixth cooling water passage 14 g are connected to the downstream side of the cooling water pump 20 via the downstream switching valve 32.

  The cooling water pump 20 employed in the present embodiment is a diaphragm pump. Although not shown, check valves for preventing a back flow of cooling water during pump operation are respectively provided on the upstream side and the downstream side. ing. Further, the diaphragm provided in the cooling water pump (diaphragm pump) 20 is pumped by turning on / off the electromagnet.

  Further, as shown in FIG. 8, the switching valves 31 and 32 employed in this embodiment are electromagnetic three-way valves. FIG. 8A shows a state in which both switching valves 31 and 32 are OFF. b) shows a state in which both switching valves 31 and 32 are ON. As shown in FIG. 5A, when both switching valves 31 and 32 are OFF, the second cooling water passage 14b connected to the downstream side of the cooling water pump 20 is connected to the sixth cooling water via the cooling water pump 20. It communicates with the passage 14g. Therefore, in this state, the cooling water stored in the lower reservoir chamber 19 is supplied toward the pressure regulating chamber 13 (water supply operation).

  Further, as shown in FIG. 5B, when both switching valves 31 and 32 are ON, the fifth cooling water passage 14f connected to the downstream side of the cooling water pump 20 is cooled via the cooling water pump 20. The second cooling water passage 14b connected to the upstream side of the water pump 20 is communicated. Therefore, in this state, the cooling water on the pressure regulating chamber 13 side is drained toward the lower reservoir chamber 19 (drainage operation). Note that both the switching valves 31 and 32 may be ON in the same figure (a) and OFF in the same figure (b).

  In the control device 30, the cooling water pump 20 and both switching valves 31 and 32 are operated based on the water level WL of the pressure regulating chamber 13, the internal pressure PT, the upper cooling water temperature TW 1, and the lower cooling water temperature TW 2 of the lower reservoir 19. Thus, the cooling water temperature is controlled to fall within a predetermined temperature range. Specifically, this control is performed according to the pump drive control routine shown in FIGS. Since this routine basically performs the same process as the pump drive control routine shown in FIGS. 3 and 4, the same reference numerals as those shown in FIGS. Detailed description will be omitted.

  In step S2, when the water level WL of the cooling water stored in the pressure regulating chamber 13 is determined to be less than the upper limit water level Hw (WL <Hw) and the process proceeds to step S3 ′, the cooling water pump 20 is operated at high (H). At the same time, both switching valves 31 and 32 are turned off (high water supply operation), and the process returns to step S1. The high operation of the cooling water pump 20 is performed by shortening the ON / OFF cycle of the electromagnet, speeding up the reciprocating operation of the diaphragm, and increasing the discharge amount of the cooling water.

  Then, it is determined that the water level WL in the pressure regulating chamber 13 has reached the upper limit water level Hw (WL ≧ Hw), the process proceeds to step S4, and the spatial internal pressure of the pressure regulating chamber 13 detected by the internal pressure sensor 23 in steps S4 and S5. PT is compared with a preset primary specified pressure Mpt. If PT> Mpt, that is, if the internal pressure PT is relatively high immediately after the water level WL reaches the upper limit water level Hw, the process proceeds to step S6 ′, and both the switching valves 31, 32 are turned on and the cooling water is supplied. The pump 20 is operated at high (H).

  As shown in FIG. 8 (b), when both switching valves 31, 32 are turned ON, the flow path connected to the cooling water pump 20 is switched, and the fifth and fourth cooling water passages 14c, 14d communicated with each other. The cooling water passage 14f is connected to the upstream side of the cooling water pump 20, and the second cooling water passage 14b is connected to the downstream side. As a result, the cooling water pump 20 enters a high drainage operation, the water level WL in the pressure regulating chamber 13 decreases at a relatively high speed, and the internal pressure PT is reduced.

  When the internal pressure PT has decreased to the primary specified pressure Mpt or less (PT ≦ Mpt), the process proceeds to step S7 ′, the cooling water pump 20 is operated low (L), and both switching valves 31 and 32 are turned on ( Low drainage operation), the process proceeds to step S8. The low operation of the cooling water pump 20 is performed by increasing the ON / OFF cycle of the electromagnet, increasing the reciprocating operation interval of the diaphragm, and decreasing the discharge amount of the cooling water.

  Thereafter, the same processing as in the first embodiment described above is performed from step S8 to S11. When it is determined in step S11 that the upper cooling water temperature TW1 exceeds the target upper specified water temperature Ltw1 (TW1> Ltw1), Proceeding to step S12 ′, the low water discharge operation of the cooling water pump 20 is continued and the saturation temperature of the cooling water is slowly lowered.

On the other hand, if it is determined in step S11 that the upper cooling water temperature TW1 is lower than the target upper specified water temperature Ltw1 (TW1 ≦ Ltw1), it is not necessary to lower the saturation temperature of the cooling water, so in step S13 ′, the cooling water pump 20 is stopped, both switching valves 31 and 32 are turned OFF, and the process proceeds to step S14. And from step S14 to S17, the same process as the first embodiment described above is performed,
If it is determined in step S17 that the lower cooling water temperature TW2 is higher than the target lower specified water temperature Ltw2 (TW2> Ltw2), the process returns to step S3 ′, and if the lower cooling water temperature TW2 is lower than the target lower specified water temperature Ltw2 If it is determined (TW2 ≦ Ltw2), the process proceeds to step S18 ′. If it progresses to step S18 ', in order to perform a low water supply operation, while operating the cooling water pump 20 low, both the switching valves 31 and 32 are turned off, and it returns to step S1. The control operation of the cooling fan 12a is the same as that in the first embodiment, and a description thereof will be omitted.

  Thus, in this embodiment, since the cooling water pump 20 is a unidirectional pump, in addition to the effects of the first embodiment described above, not only can the control mechanism such as the pump drive circuit be simplified, A non-rotating pump such as a diaphragm pump can also be used, and the product cost can be reduced.

1 ... Motor generator for running,
2 ... Inverter,
3 ... Battery
11 ... Boiling cooler,
12: Capacitor,
12a ... Electric cooling fan,
13 ... pressure regulating chamber,
14 ... Lower cooling water passage,
16 ... reservoir chamber,
17 ... upper return passage,
18 ... water vapor reflux passage,
19 ... Lower chamber,
20 ... cooling water pump,
21 ... Cooling water recirculation passage,
22 ... Water level sensor,
23 ... Internal pressure sensor,
24 ... Water temperature sensor,
25. Check valve,
28 ... Internal pressure sensor,
29 ... Water temperature sensor,
30 ... Control device Hpa ... Target upper specified pressure Hw ... Upper limit water level Lpt ... Target specified pressure Ltw1 ... Target upper specified water temperature Ltw2 ... Target lower specified water temperature Lw ... Lower limit water level Mpt ... Primary specified pressure PA ... Internal pressure PT (in the reservoir chamber) ... Space pressure TW1 (in the pressure regulating chamber) ... Upper cooling water temperature TW2 ... Lower cooling water temperature WL ... Water level

Japanese Patent Laid-Open No. 2001-349881

Claims (3)

A liquid-phase refrigerant passage through which a liquid-phase refrigerant for cooling the heating element flows;
Refrigerating gas phase refrigerant generated by boiling in the liquid phase refrigerant passage to the liquid phase refrigerant passage, and a refrigerant reflux passage communicating with the liquid phase refrigerant passage to form a closed circulation path;
A pressure regulating chamber provided in an upper portion of the liquid phase refrigerant passage and retaining the liquid phase refrigerant;
Check means provided in the gas-phase refrigerant passage communicating with an upper portion of the pressure-regulating chamber and allowing only the gas-phase refrigerant to flow from the pressure-regulating chamber to the gas-phase refrigerant passage side;
A pump unit that is provided in the liquid phase refrigerant passage and causes the liquid phase refrigerant to flow;
A boiling cooling device comprising a control means for controlling the operation of the pump unit;
The pump unit can flow the liquid-phase refrigerant bidirectionally in the liquid-phase refrigerant passage,
The control means includes
The temperature of the liquid phase refrigerant stored in the pressure regulating chamber is compared with a preset target saturation temperature, and the pump unit is driven so that the temperature of the liquid phase refrigerant falls within the target saturation temperature range. To reduce the space pressure in the pressure regulating chamber ,
After the temperature of the liquid phase refrigerant falls within the target saturation temperature range, the liquid level in the pressure regulating chamber is compared with a preset lower limit liquid level, and the liquid level is lower than the lower limit liquid level. In this case, the temperature of the liquid-phase refrigerant passage is compared with the temperature of the liquid-phase refrigerant on the opposite side of the pump unit with respect to the pressure regulating chamber, and a preset target specified temperature is determined. When the temperature is higher than the specified temperature, the pump unit is driven at a high feed rate, and when the temperature of the liquid-phase refrigerant is lower than the target specified temperature, the liquid level in the pressure adjusting chamber is set in advance. The boiling cooling device, wherein the liquid-phase refrigerant is sent until the upper limit water level is reached. A reservoir chamber that retains the gas-phase refrigerant and a condenser that cools the gas-phase refrigerant downstream from the reservoir chamber are provided in the refrigerant reflux passage.
The condenser is provided with a cooling fan for cooling the condenser,
The control means compares the internal pressure of the reservoir chamber with a preset target specified pressure, and drives the cooling fan when the internal pressure of the reservoir chamber is higher than the target specified pressure. cooling apparatus according to 1. A reservoir chamber that retains the gas-phase refrigerant and a condenser that cools the gas-phase refrigerant downstream from the reservoir chamber are provided in the refrigerant reflux passage.
The control means compares the internal pressure of the reservoir chamber with a preset target specified pressure, and when the internal pressure of the reservoir chamber is higher than the target specified pressure, drives the cooling fan at a high speed, When the internal pressure is lower than the target specified pressure, the temperature of the liquid phase refrigerant downstream of the condenser is compared with the target specified temperature, and when the temperature of the liquid phase refrigerant is higher than the target specified temperature, the cooling cooling apparatus according to claim 1 or claim 2, characterized in that said low-speed drive of the fan.

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