JP2016061260A - Ebullient cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of abrupt ebullition at an upstream part immediately before a water pump for sending a liquid phase refrigerant to a refrigerant passage, and to properly control a liquid phase refrigerant amount in an air-liquid separator.SOLUTION: Since a WP 62 is continuously driven during the ebullition cooling of an engine 10, a liquid phase refrigerant in a catch tank 42 can be supplied to an upstream part immediately before the WP 22, and the abrupt ebullition of the liquid phase refrigerant at the upstream part immediately before the WP 22 caused by abrupt decompression in the air-liquid separator 16 can be prevented. Also, since the WP 22 is driven when a liquid level height of the liquid phase refrigerant of the air-liquid separator 16 is lower than a position of a level sensor 50, the liquid phase refrigerant in the catch tank 42 can be replenished to the air-liquid separator 16. Furthermore, since a control valve 56 is opened when the liquid level height of the liquid phase refrigerant of the air-liquid separator 16 reaches the position of the level sensor 60, the spill-out of the liquid phase refrigerant to an atmospheric pressure system including the air-liquid separator 16 can be prevented.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a boiling cooling device.

  Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2012-172617, as a cooling device for an internal combustion engine, cooling is performed by using the boiling vaporization heat of a refrigerant flowing in a refrigerant passage (for example, a water jacket) formed inside the engine. A boiling cooling device for performing the above is known. This boiling cooling device includes a gas-liquid separator that separates the refrigerant discharged from the refrigerant passage into a liquid-phase refrigerant and a gas-phase refrigerant. The liquid phase refrigerant separated by the gas-liquid separator is sent to a first water pump for sending the liquid phase refrigerant to the refrigerant passage. On the other hand, the gas-phase refrigerant separated by the gas-liquid separator is supplied to a turbine or the like to recover its thermal energy, then cooled by a condenser, returned to the liquid-phase refrigerant, and sent to the first water pump. This condenser is connected not only to the first water pump but also to the gas-liquid separator, and the liquid-phase refrigerant from the condenser is sent to the first water pump and the gas-liquid separator by the second water pump. Since the refrigerant flow rate from the second water pump is variable so that the amount of steam generated in the cooling passage is constant, excessive cooling and overheating of the internal combustion engine can be suppressed.

JP 2012-172617 A JP 59-111010 A

  By the way, when the inside of a gas-liquid separator is pressure-reduced rapidly in the said boiling cooling device, intense boiling may generate | occur | produce in the liquid phase refrigerant | coolant in a gas-liquid separator. Here, since the gas-liquid separator and the first water pump are connected, if a violent boiling occurs in the liquid-phase refrigerant in the gas-liquid separator, the liquid-phase refrigerant in the immediately upstream portion of the first water pump is also generated. Vigorous boiling occurs. When a severe boiling occurs in the liquid phase refrigerant immediately upstream of the first water pump, the first water pump idles and the flow rate of the refrigerant that should be sent to the refrigerant passage decreases, so that the internal combustion engine is insufficiently cooled. There is a problem.

  In this respect, since the second water pump can always supply the refrigerant, it is possible to suppress the occurrence of severe boiling in the liquid-phase refrigerant immediately upstream of the first water pump. However, since the driving of the second water pump does not take into account fluctuations in the amount of liquid phase refrigerant in the gas-liquid separator, it can be handled even if the amount of liquid phase refrigerant in the gas-liquid separator decreases more than necessary. I can't. Further, since the refrigerant from the second water pump is sent not only to the first water pump but also to the gas-liquid separator, when the amount of the liquid-phase refrigerant in the gas-liquid separator is extremely increased, a gas-phase refrigerant such as a turbine is used. There is a risk that the liquid-phase refrigerant will flow into the first passage.

  The present invention has been made to solve at least one of the above-described problems. That is, an object of the present invention is to control the amount of liquid phase refrigerant in a gas-liquid separator appropriately by suppressing the occurrence of intense boiling in the immediately upstream portion of the water pump for sending the liquid phase refrigerant to the refrigerant passage.

The present invention is a boiling cooling device comprising:
An internal combustion engine that is cooled by the boiling of the refrigerant flowing in the refrigerant passage formed therein;
A gas-liquid separator that separates the refrigerant discharged from the internal combustion engine into a liquid-phase refrigerant and a gas-phase refrigerant;
Recovery means for recovering thermal energy of the gas-phase refrigerant separated by the gas-liquid separator;
A capacitor for cooling the gas-phase refrigerant after recovery of thermal energy to return it to the liquid-phase refrigerant;
A first passage connecting the capacitor and the refrigerant passage;
A second passage branched in the middle of the first passage and connected to the gas-liquid separator;
A water pump provided between the refrigerant passage and the connection portion where the first passage connects to the second passage, and a liquid pump for sending the liquid-phase refrigerant in the first passage to the refrigerant passage;
A third passage connecting the condenser and the water pump by bypassing the connecting portion in the first passage;
A fourth passage connecting the gas-liquid separator and the condenser without going through the recovery means;
Refrigerant supply means for sending the liquid phase refrigerant from the condenser to the water pump via the third passage during boiling cooling of the internal combustion engine;
During the boiling cooling of the internal combustion engine, when the liquid level of the liquid phase refrigerant of the gas-liquid separator becomes less than the first reference value, the liquid phase refrigerant from the capacitor is caused to pass through the second passage. Refrigerant replenishing means for sending to the gas-liquid separator;
During boiling cooling of the internal combustion engine, when the liquid level of the liquid-phase refrigerant of the gas-liquid separator becomes equal to or higher than a second reference value that is larger than the first reference value, the gas-liquid separator is separated. Refrigerant leakage means for sending liquid phase refrigerant to the capacitor via the fourth passage;
It is characterized by providing.

  According to the present invention, during the boiling cooling of the internal combustion engine, the liquid phase refrigerant from the condenser can be supplied to the water pump via the third passage. Therefore, it is possible to suppress the occurrence of intense boiling in the immediately upstream portion of the water pump. Further, during the boiling cooling of the internal combustion engine, when the liquid level of the liquid phase refrigerant of the gas-liquid separator becomes less than the first reference value, the liquid phase refrigerant from the condenser is passed through the second passage. The gas-liquid separator can be replenished, and when the liquid level is equal to or higher than the second reference value, the liquid-phase refrigerant separated by the gas-liquid separator is passed through the fourth passage to the condenser. It can also leak. Therefore, the amount of liquid phase refrigerant in the gas-liquid separator can be appropriately controlled.

It is a figure for demonstrating the structure of the boiling cooling device 100 of Embodiment 1. FIG. It is a flowchart which shows the control routine of WP44. It is the figure which showed the outline of the ON / OFF function of the level sensor. It is a three-phase diagram of a refrigerant. 7 is a timing chart for explaining problems when the pressure relief valve 52 is opened. 6 is a timing chart for explaining drive control of the WP62. It is a flowchart which shows the control routine of WP62. 4 is a timing chart for explaining opening / closing control of a control valve 56; 3 is a flowchart showing a control routine of a control valve 56. It is the figure which showed the example of a setting of the coefficient Yn. It is a figure for demonstrating the structure of the boiling cooling device 200 of Embodiment 3. FIG. 7 is a flowchart showing a control routine for the WP 44 and the control valve 72.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted. The present invention is not limited to the following embodiments.

Embodiment 1 FIG.
First, the first embodiment of the present invention will be described with reference to FIGS.

[Description of device configuration]
FIG. 1 is a diagram for explaining the configuration of the boiling cooling device 100 of the first embodiment. As shown in FIG. 1, the boiling cooling device 100 includes a refrigerant passage 12 formed inside the engine 10. The refrigerant flowing through the refrigerant passage 12 receives the heat of the engine 10 and boils, whereby the engine 10 is cooled. The refrigerant passage 12 is a water jacket formed around the cylinder of the engine 10, but is not particularly limited as long as the refrigerant can flow through the engine 10. Moreover, the refrigerant | coolant which distribute | circulates the inside of the refrigerant path 12 will not be specifically limited if the heat of the engine 10 is received and it boils.

  The refrigerant passage 12 is connected to the gas-liquid separator 16 via the refrigerant passage 14. The refrigerant passage 14 is configured by a tube or a hose that can withstand high temperatures and high pressures. The gas-liquid separator 16 separates the refrigerant flowing into the gas-liquid separator 16 into a liquid phase refrigerant and a gas phase refrigerant. The gas-liquid separator 16 is connected to a WP (water pump) 22 through refrigerant passages 18 and 20. The WP 22 is a mechanical pump that uses a crankshaft provided in the engine 10 as a drive source, but an electric centrifugal pump can also be used. A part of the liquid-phase refrigerant separated by the gas-liquid separator 16 flows into the WP 22 via the refrigerant passages 18 and 20 and is sent to the refrigerant passage 12 by driving the WP 22.

  In addition, the boiling cooling device 100 includes an exhaust heat steam generator 24. The exhaust heat steam generator 24 is provided in an exhaust passage (not shown) of the engine 10. When the liquid-phase refrigerant separated by the gas-liquid separator 16 flows into the exhaust heat steam generator 24 via the refrigerant passages 18 and 26, a part of the liquid refrigerant becomes steam by the exhaust heat. The liquid-phase refrigerant mixed with the steam flows into the gas-liquid separator 16 from the exhaust heat steam generator 24 via the refrigerant passage 28.

  Further, the boiling cooling device 100 includes a superheater 30, a supersonic nozzle 32, and a turbine 34. The superheater 30 is provided on the upstream side of the exhaust heat steam generator 24 in the exhaust passage. When the gas-phase refrigerant separated by the gas-liquid separator 16 flows into the superheater 30 via the refrigerant passage 36, it becomes superheated steam due to the exhaust heat. The superheated steam flows into the supersonic nozzle 32 via the refrigerant passage 38 and is sprayed onto the turbine 34. As the superheated steam is sprayed, the turbine 34 rotates. Since a generator (not shown) is connected to the turbine 34, electricity is generated in the generator when the turbine 34 rotates. The generated electricity is stored in a storage battery (not shown). A reduction gear (not shown) may be connected to the turbine 34 and the engine 10 may be assisted through the reduction gear.

  The boiling cooling device 100 includes a condenser 40, a catch tank 42, a WP 44, and a check valve 46. The condenser 40 is connected to the turbine 34 via the refrigerant passage 48. The gas-phase refrigerant that has flowed into the condenser 40 from the turbine 34 via the refrigerant passage 48 is cooled in the condenser 40, returned to the liquid-phase refrigerant, and temporarily stored in the catch tank 42. The WP 44 is an electric pump for sending the liquid-phase refrigerant stored in the catch tank 42 to the refrigerant passage 20. The WP 44 supplies liquid-phase refrigerant from a low pressure region (for example, 10 to 20 kPaG) to a normal pressure region (for example, 100 kPaG). It is configured to be able to send liquids. ON / OFF of the driving of the WP 44 is controlled based on an ON / OFF signal from a level sensor 50 that detects the liquid level height of the liquid phase refrigerant in the gas-liquid separator 16 (details will be described later). When the WP 44 is driven, the liquid-phase refrigerant in the catch tank 42 is sent to the WP 22 via the refrigerant passage 20, and is simultaneously sent to the gas-liquid separator 16 and the exhaust heat steam generator 24 via the refrigerant passage 18. . By providing the check valve 46, the backflow of the liquid phase refrigerant from the WP 22 side to the catch tank 42 side is prevented.

  As described above, the liquid-phase refrigerant receives waste heat from the engine 10 in the engine 10, the exhaust heat steam generator 24, and the superheater 30, and becomes a high-temperature and high-pressure gas-phase refrigerant. The generator and the storage battery connected to the turbine 34 convert the thermal energy received by the gas-phase refrigerant into electrical energy and recover it. When a speed reducer is connected to the turbine 34, the speed reducer recovers thermal energy of the gas-phase refrigerant as mechanical power. The gas-phase refrigerant that has passed through the turbine 34 is returned again to the liquid-phase refrigerant in the condenser 40, and is sent to the engine 10, the exhaust heat steam generator 24, and the superheater 30 by driving the WPs 22 and 44. Thus, the boiling cooling device 100 also functions as a Rankine cycle system.

  In addition, the boiling cooling device 100 includes a pressure relief valve 52 for reducing the pressure in the gas phase of the gas-liquid separator 16. The pressure relief valve 52 is, for example, an electromagnetic valve, and is provided in the refrigerant passage 54 that bypasses the superheater 30, the supersonic nozzle 32, and the turbine 34 and connects the gas-liquid separator 16 and the condenser 40. When the pressure relief valve 52 is opened, the gas-phase refrigerant in the gas-liquid separator 16 flows into the condenser 40 via the refrigerant passage 54 without passing through the superheater 30 or the like, and thereby the pressure in the gas-liquid separator 16 is increased. Decreases.

  In addition, the boiling cooling device 100 includes a control valve 56 for leaking the liquid-phase refrigerant in the gas-liquid separator 16 to the condenser 40. The control valve 56 is, for example, an electromagnetic valve, and is provided in a refrigerant passage 58 that connects the gas-liquid separator 16 and the condenser 40. ON / OFF of the drive of the control valve 56 is provided based on the ON / OFF signal from the level sensor 60 that is provided above the level sensor 50 and detects the liquid level height of the liquid phase refrigerant in the gas-liquid separator 16. It is controlled (details will be described later). When the control valve 56 is opened, the liquid phase refrigerant of the gas-liquid separator 16 flows into the condenser 40 via the refrigerant passage 58.

  The boiling cooling device 100 includes a WP 62 and a check valve 64. The WP 62 and the check valve 64 are provided in the refrigerant passage 68 that connects the WP 22 and the catch tank 42 by bypassing the connection portion 66 of the refrigerant passage 18 and the refrigerant passage 20. ON / OFF of the driving of the WP 62 is controlled based on whether or not the engine 10 is boil-cooled (details will be described later). When the WP 62 is driven, the liquid-phase refrigerant stored in the catch tank 42 is sent to the WP 22 via the refrigerant passage 68 without passing through the connection portion 66 or the like. By providing the check valve 64, the backflow of the liquid phase refrigerant from the WP 22 side to the catch tank 42 side is prevented.

  The boiling cooling device 100 further includes an ECU (Electronic Control Unit) 70. The ECU 70 includes at least an input / output interface, a memory, and a CPU. The input / output interface is provided to capture sensor signals from various sensors and to output operation signals to the actuator. Level sensors 50 and 60 are included in sensors from which the ECU 70 takes signals. The actuators from which the ECU 70 outputs operation signals include the WPs 44 and 62, the pressure relief valve 52, and the control valve 56. The memory stores various control programs, various maps, and the like. The CPU reads out and executes a control program or the like from the memory, and generates an operation signal based on the acquired sensor signal.

[Features of Embodiment 1]
The control by the ECU 70 includes drive control of the WPs 44 and 62 and open / close control of the pressure relief valve 52 and the control valve 56. First, drive control of the WP 44 will be described. The drive control of the WP 44 by the ECU 70 is performed intermittently for the purpose of replenishing the gas-liquid separator 16 with the liquid-phase refrigerant in the catch tank 42 when the liquid-phase refrigerant in the gas-liquid separator 16 decreases. Yes, based on the ON / OFF signal from the level sensor 50.

  FIG. 2 is a flowchart showing a control routine of WP44. The control routine shown in FIG. 2 is repeatedly executed every predetermined control cycle immediately after the engine 10 is started. In the routine shown in FIG. 2, first, the ECU 70 determines whether or not the engine 10 is cooled by boiling (step S10). The ECU 70 determines whether or not boiling cooling is being performed based on whether or not the refrigerant temperature in the refrigerant passage 12 is equal to or higher than a predetermined temperature. The refrigerant temperature of the engine 10 may be detected from a temperature sensor or a pressure sensor separately provided in the refrigerant passage 14 or the gas-liquid separator 16 or may be estimated from the operating state of the engine 10. In this step, when it is determined that the boiling cooling is not performed, the ECU 70 ends this routine.

  When it is determined in step S10 that boiling cooling is performed, the ECU 70 determines whether or not the level sensor 50 is turned on (step S12). The ECU 70 determines whether the level sensor 50 is ON based on the ON / OFF signal from the level sensor 50. FIG. 3 is a diagram showing an outline of the ON / OFF function of the level sensor 50. As shown in FIG. 3, when the liquid level height of the liquid phase refrigerant of the gas-liquid separator 16 is lower than the position of the level sensor 50, the level sensor 50 issues an ON signal, and the liquid level height of the level sensor 50 The level sensor 50 issues an OFF signal when the position is exceeded. If an OFF signal is detected in this step, the ECU 70 proceeds to step S20.

  If an ON signal is detected in step S12, the ECU 70 starts driving the WP 44 (step S14), and determines whether or not the level sensor 50 is OFF (step S16). If an ON signal is detected in step S16, the ECU 70 returns to step S14. That is, the drive of the WP 44 is continued until the liquid level height of the liquid phase refrigerant in the gas-liquid separator 16 becomes equal to or higher than the position of the level sensor 50. If an OFF signal is detected in step S16, the ECU 70 stops driving the WP 44 (step S18) and proceeds to step S20.

  In step S20, the ECU 70 determines whether or not the boiling cooling of the engine 10 has been completed. The ECU 70 determines whether or not the boiling cooling is completed based on whether or not the refrigerant temperature in the refrigerant passage 12 is equal to or higher than a predetermined temperature. The process in this step is the opposite of the process in step S10. In this step, when it is determined that the boiling cooling is not completed, the ECU 70 returns to step S12. In this step, when it is determined that the boiling cooling is finished, the ECU 70 finishes this routine.

  Next, opening / closing control of the pressure relief valve 52 will be described. The opening / closing control of the pressure relief valve 52 by the ECU 70 is performed for the purpose of reducing the pressure in the gas phase of the gas-liquid separator 16. Specifically, in this control, when the pressure in the gas phase of the gas-liquid separator 16 falls below the normal pressure to high pressure range (for example, 100 to 200 kPaG), the pressure relief valve 52 is closed, and the pressure exceeds the predetermined pressure (for example, 200 kPaG). In this case, the pressure relief valve 52 is opened. The pressure in the gas phase of the gas-liquid separator 16 is obtained from a pressure sensor provided separately in the gas-liquid separator 16 or in the refrigerant passage 54 upstream of the pressure relief valve 52 (gas-liquid separator 16 side). Detected.

  Next, drive control of the WP 62 will be described. FIG. 4 is a three-phase diagram of the refrigerant. As shown in FIG. 4, the state of the refrigerant depends on the pressure and temperature, and in order to maintain the liquid state C shown in the figure, the temperature is lowered if the pressure is constant, and the pressure is increased if the temperature is constant. There is a need. Moreover, the boundary line of the liquid and gas shown in the figure represents a vapor pressure curve, and indicates that the temperature at which the refrigerant boils (boiling temperature) changes according to the pressure.

  Here, since the pressure in the refrigerant passage 54 on the downstream side (capacitor 40 side) of the pressure relief valve 52 is equal to or lower than the normal pressure, when the pressure relief valve 52 is opened, the gas-liquid separator 16 is rapidly decompressed. The When the pressure inside the gas-liquid separator 16 is rapidly reduced, the boiling temperature of the liquid-phase refrigerant in the gas-liquid separator 16 rapidly decreases. When the boiling temperature after the drop is lower than the temperature of the liquid-phase refrigerant in the gas-liquid separator 16, the liquid-phase refrigerant in the gas-liquid separator 16 boils, and when the temperature difference is large, the liquid-phase refrigerant boils. Become intense. Since the gas-liquid separator 16 is connected to the refrigerant passage 18 and the refrigerant passage 20, if the liquid-phase refrigerant in the gas-liquid separator 16 boils violently, the liquid-phase refrigerant in the refrigerant passage 20 between the WP 22 and the connection portion 66 also changes. There is a problem of boiling violently.

FIG. 5 is a timing chart for explaining problems when the pressure relief valve 52 is opened. When opening the pressure relief valve 52 at time t _1, the boiling temperature with decreasing pressure (dashed line) decreases. However, since the WP 44 is driven by the above-described drive control of the WP 44 from time t ₁ to time t ₂ , the refrigerant passage 20 between the WP 22 and the connection portion 66 is supplied by the liquid-phase refrigerant sent from the catch tank 42. The temperature of the liquid phase refrigerant (WP22 pre-water temperature) decreases. Therefore, during this time, the boiling temperature does not fall below the WP22 pre-water temperature.

However, when driving at a time _{t 2} WP44 is stopped, the boiling temperature emerges cases below the water temperature before WP22. When the temperature difference between the boiling temperature and the WP22 pre-water temperature is large, not only the liquid-phase refrigerant in the gas-liquid separator 16 but also the liquid-phase refrigerant in the refrigerant passage 20 between the WP22 and the connection portion 66, that is, the direct flow of the WP22. The upstream liquid phase refrigerant also boils violently, causing the WP 22 to idle. If it does so, the liquid phase refrigerant | coolant flow rate (refrigerant channel | path 12 inlet refrigerant | coolant flow rate) which should be sent to the refrigerant path 12 from WP22 will fall. Similarly, from time _{t 3} to time _{t 4} WP44 is driven again, the time _{t 4} after the driving of WP44 is stopped, the boiling temperature falls below the temperature prior WP22. Thus, when the liquid phase refrigerant in the refrigerant passage 20 between the WP 22 and the connection portion 66 boils violently, the engine 10 is not sufficiently cooled.

  The drive control of the WP 62 is performed for the purpose of suppressing the occurrence of such problems. FIG. 6 is a timing chart for explaining the drive control of the WP 62. Each time shown in FIG. 6 corresponds to each time shown in FIG. As shown in FIG. 6, the WP 62 is continuously driven. If the WP 62 is continuously driven, the liquid phase refrigerant is always sent from the catch tank 42. Therefore, it is possible to prevent the boiling temperature from falling below the WP22 pre-water temperature due to the rapid pressure reduction in the gas-liquid separator 16. In the drive control of the WP 62, it is only necessary to always supply the liquid phase refrigerant in the catch tank 42 to the refrigerant passage 20 between the WP 22 and the connection portion 66. Therefore, in the present embodiment, the refrigerant flow rate from the WP 62 is very small (a constant amount). Set to.

  FIG. 7 is a flowchart showing a control routine of WP62. It is assumed that the control routine shown in FIG. 7 is repeatedly executed every predetermined control cycle immediately after the engine 10 is started. In the routine shown in FIG. 7, first, the ECU 70 determines whether or not the engine 10 is cooled by boiling (step S22). The processing in this step is the same as the processing in step S10 in FIG. In this step, when it is determined that the boiling cooling is not performed, the ECU 70 ends this routine.

  If it is determined in step S22 that boiling cooling is being performed, the ECU 70 starts driving the WP 62 (step S24), and determines whether boiling cooling of the engine 10 has been completed (step S26). The process of step S26 is the opposite process to the process of step S22. If it is determined in step S26 that boiling cooling has not ended, the ECU 70 returns to step S24. That is, the driving of the WP 62 is continued until the boiling cooling is completed. If it is determined in step S26 that boiling cooling has been completed, the ECU 70 stops driving the WP 62 (step S28), and this routine is terminated.

  Finally, opening / closing control of the control valve 56 will be described. In the drive control of the WP 62 described above, the refrigerant flow rate from the WP 62 is very small. However, the driving of the WP 62 is not linked to the liquid level height of the liquid-phase refrigerant in the gas-liquid separator 16, and the path from the gas-liquid separator 16 to the condenser 40 (refrigerant passages 36, 38, 48, 54). ) Can only flow in the gas phase refrigerant, the liquid phase refrigerant may overflow into the atmospheric system including the gas-liquid separator 16 due to the driving of the WP62.

The opening / closing control of the control valve 56 is performed for the purpose of suppressing the occurrence of such problems. FIG. 8 is a timing chart for explaining the opening / closing control of the control valve 56. Liquid level of the liquid refrigerant in the gas-liquid separator 16 is to have reached the position H ₁ of the level sensor 60 at time t _5. Here, the specification of the level sensor 60 (see FIG. 3) is similar to the specification of the level sensor 50, the level sensor 60 emits an OFF signal at time _{t 5.} In response to the OFF signal, the control valve 56 is opened, and the liquid phase refrigerant of the gas-liquid separator 16 is sent to the condenser 40 via the refrigerant passage 58. Thereby, the liquid level height of the liquid phase refrigerant of the gas-liquid separator 16 is lowered. Then, the level sensor 60 at time t ₆ the liquid level is lower than the position H ₁ emits an ON signal, the control valve 56 closes by receiving the ON signal.

  FIG. 9 is a flowchart showing a control routine of the control valve 56. Note that the control routine shown in FIG. 9 is repeatedly executed every predetermined control period from immediately after the engine 10 is started. In the routine shown in FIG. 9, first, the ECU 70 determines whether or not the engine 10 is cooled by boiling (step S30). The processing in this step is the same as the processing in step S10 in FIG. In this step, when it is determined that the boiling cooling is not performed, the ECU 70 ends this routine.

  If it is determined in step S30 that boiling cooling is performed, the ECU 70 determines whether or not the level sensor 60 is turned off (step S32). The ECU 70 determines whether or not the level sensor 60 is ON based on the ON / OFF signal from the level sensor 60. If an ON signal is detected in this step, the ECU 70 proceeds to step S40.

  If an OFF signal is detected in step S32, the ECU 70 opens the control valve 56 (step S34) and determines whether or not the level sensor 60 is ON (step S36). If an OFF signal is detected in step S36, the ECU 70 returns to step S34. That is, the driving of the WP 44 is continued until the liquid level of the liquid phase refrigerant in the gas-liquid separator 16 becomes lower than the position of the level sensor 60. When the ON signal is detected in step S36, the ECU 70 closes the control valve 56 (step S38), and proceeds to step S40.

  In step S40, the ECU 70 determines whether or not the boiling cooling of the engine 10 has been completed. The ECU 70 determines whether or not the boiling cooling is completed based on whether or not the refrigerant temperature in the refrigerant passage 12 is equal to or higher than a predetermined temperature. The process in this step is the opposite of the process in step S30. In this step, when it is determined that the boiling cooling is not completed, the ECU 70 returns to step S32. In this step, when it is determined that the boiling cooling is finished, the ECU 70 finishes this routine.

  As described above, according to the present embodiment, the following effects can be obtained by various controls during boiling cooling of the engine 10. That is, the liquid-phase refrigerant in the catch tank 42 can be supplemented to the gas-liquid separator 16 by the drive control of the WP 44. Further, the pressure in the gas phase of the gas-liquid separator 16 can be reduced by the opening / closing control of the pressure relief valve 52. Further, since the liquid phase refrigerant in the catch tank 42 can be supplied to the immediately upstream portion of the WP 22 by the drive control of the WP 62, the liquid phase refrigerant immediately upstream of the WP 22 due to the sudden pressure reduction in the gas-liquid separator 16 is intense. Boiling can be prevented. Further, the opening / closing control of the control valve 56 can prevent the liquid-phase refrigerant from overflowing into the atmospheric system including the gas-liquid separator 16.

In the first embodiment, the refrigerant passage 12 is the “refrigerant passage” of the present invention, the engine 10 is the “internal combustion engine” of the present invention, and the gas-liquid separator 16 is the “gas-liquid separator” of the present invention. Further, the superheater 30, the supersonic nozzle 32, the turbine 34, the generator and the storage battery are the “recovery means” of the present invention, the condenser 40 is the “condenser” of the present invention, and the refrigerant passage 20 is the “first passage” of the present invention. The refrigerant passage 18 is the “second passage” of the present invention, the connection portion 66 is the “connection portion” of the present invention, the WP 22 is the “water pump” of the present invention, and the refrigerant passage 68 is the “second passage” of the present invention. The refrigerant passage 58 corresponds to the “fourth passage” of the present invention.
In the first embodiment, the ECU 70 executes the series of processes shown in FIG. 7 so that the “refrigerant supply means” of the present invention causes the ECU 70 to execute the series of processes shown in FIG. The “refrigerant replenishing means” of the present invention is realized by the ECU 70 executing the series of processes shown in FIG. 9.

Embodiment 2. FIG.
Next, Embodiment 2 of the present invention will be described with reference to FIG.
In the first embodiment, the refrigerant flow rate from the WP 62 is set to a constant amount. However, depending on the operating region of the engine 10, there is a concern about malfunctions in the apparatus. For example, when the refrigerant flow rate is too high, the amount of vapor generated in the refrigerant passage 12 decreases in the low load region. In addition, when the refrigerant flow rate is too small, severe boiling occurs immediately upstream of the WP 22 even though the liquid-phase refrigerant is supplied.

Therefore, in the present embodiment, the WP 62 is a variable capacity type, and the rotation speed of the WP 62 is changed based on the following formula (1).
WP62 rotational speed = X rpm (pump rated rotational speed) × coefficient Yn (1)
The coefficient Yn of the equation (1) is determined in advance according to the operation region (rotational speed and load) of the engine 10 and stored in a memory in the ECU 70. FIG. 10 is a diagram illustrating a setting example of the coefficient Yn (Y ₁ <Y ₂ <Y ₃ ).

  As described above, according to the present embodiment, an optimal amount of refrigerant can be sent to the immediately upstream portion of WP22.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIGS. The present embodiment is characterized in that the functions of the WP 62 are integrated into the WP 44.

[Description of device configuration]
FIG. 11 is a diagram for explaining the configuration of the boiling cooling apparatus 200 according to the third embodiment. The boiling cooling device 200 includes a control valve 72 in the refrigerant passage 20 between the WP 44 and the check valve 46. The control valve 72 is connected to the ECU 70. Further, the refrigerant passage 68 of the boiling cooling device 200 branches from the refrigerant passage 20 between the WP 44 and the control valve 72 and bypasses the check valve 46, the control valve 72, and the connection portion 66 between the refrigerant passage 18 and the refrigerant passage 20. Thus, the WP 22 and the catch tank 42 are connected. About the other structure of the boiling cooling device 200, it is common with the structure of the boiling cooling device 100 shown in FIG.

[Features of Embodiment 3]
The control by the ECU 70 includes drive control of the WP 44 and open / close control of the pressure relief valve 52 and the control valves 56 and 72. The opening / closing control of the pressure relief valve 52 and the control valve 56 is as described in the first embodiment. Hereinafter, the drive control of the WP 22 and the opening / closing control of the control valve 72 will be described with reference to FIG.

  FIG. 12 is a flowchart showing a control routine for the WP 44 and the control valve 72. Note that the control routine shown in FIG. 12 is repeatedly executed every predetermined control period immediately after the engine 10 is started. In the routine shown in FIG. 12, first, the ECU 70 determines whether or not the engine 10 is cooled by boiling (step S42). The processing in this step is the same as the processing in step S10 in FIG. In this step, when it is determined that the boiling cooling is not performed, the ECU 70 ends this routine.

  If it is determined in step S42 that boiling cooling is being performed, the ECU 70 closes the control valve 72 (step S44) and starts driving the WP 44 (step S46). In step S46, the refrigerant flow rate from the WP 44 is set to a small flow rate (a constant amount).

  Subsequent to step S46, the ECU 70 determines whether or not the level sensor 50 is ON (step S48). The process in this step is the same as the process in step S12 in FIG. If an OFF signal is detected in this step, the ECU 70 returns to step S44 and continues the refrigerant supply at a small flow rate. On the other hand, when an ON signal is detected in this step, it can be determined that the liquid level refrigerant liquid level of the gas-liquid separator 16 is lower than the level sensor 50 position. Therefore, the ECU 70 opens the control valve 72 (step S50) and changes the refrigerant flow rate from the WP 44 (step S52) in order to replenish the gas-liquid separator 16 with the liquid-phase refrigerant in the catch tank 42. In step S52, the refrigerant flow rate from the WP 44 is set to a large flow rate (a constant amount).

  Subsequent to step S52, the ECU 70 determines whether or not the level sensor 50 is turned off (step S54). The process in this step is the same as the process in step S16 in FIG. If an ON signal is detected in this step, the ECU 70 returns to step S50. That is, the refrigerant supply at a large flow rate is continued until the liquid level height of the liquid phase refrigerant in the gas-liquid separator 16 becomes equal to or higher than the level sensor 50. If an OFF signal is detected in this step, the control valve 72 is closed (step S56), and the refrigerant flow rate from the WP 44 is changed (step S58). In step S58, the refrigerant flow rate from WP 44 is set to a low flow rate (the same flow rate as step S46).

  Subsequent to step S58, the ECU 70 determines whether or not the boiling cooling of the engine 10 has been completed (step S60). The processing in this step is the opposite of the processing in step S42. In this step, when it is determined that the boiling cooling is not completed, the ECU 70 returns to step S48. In this step, when it is determined that the boiling cooling is completed, the ECU 70 proceeds to step S62 and stops driving the WP22.

  As described above, according to the present embodiment, by combining the driving control of the WP 44 and the opening / closing control of the control valve 72, the boiling of the liquid refrigerant just upstream of the WP 22 can be prevented and the catch tank 42 can be prevented. The gas-liquid separator 16 can be replenished with the liquid refrigerant inside.

  In the third embodiment, the ECU 70 executes the processing of steps S48 to S56 in FIG. 12, so that the “refrigerant replenishing means” of the present invention is replaced by the ECU 70 in steps S42 to S46, S58, and S60 of FIG. By executing the processing, the “refrigerant supply means” of the present invention is realized.

10 Engine 12, 14, 18, 20, 26, 28, 36, 38, 48, 54, 58, 68 Refrigerant passage 16 Gas-liquid separator 22, 44, 62 WP (water pump)
24 Exhaust Heat Steam Generator 30 Superheater 32 Supersonic Nozzle 34 Turbine 40 Condenser 42 Catch Tank 46, 64 Check Valve 50, 60 Level Sensor 52 Pressure Relief Valve 56, 72 Control Valve 66 Connection 70 ECU
100,200 Boiling cooler

Claims (1)

An internal combustion engine that is cooled by the boiling of the refrigerant flowing in the refrigerant passage formed therein;
A gas-liquid separator that separates the refrigerant discharged from the internal combustion engine into a liquid-phase refrigerant and a gas-phase refrigerant;
Recovery means for recovering thermal energy of the gas-phase refrigerant separated by the gas-liquid separator;
A capacitor for cooling the gas-phase refrigerant after recovery of thermal energy to return it to the liquid-phase refrigerant;
A first passage connecting the capacitor and the refrigerant passage;
A second passage branched in the middle of the first passage and connected to the gas-liquid separator;
A water pump provided between the refrigerant passage and the connection portion where the first passage connects to the second passage, and a liquid pump for sending the liquid-phase refrigerant in the first passage to the refrigerant passage;
A third passage connecting the condenser and the water pump by bypassing the connecting portion in the first passage;
A fourth passage connecting the gas-liquid separator and the condenser without going through the recovery means;
Refrigerant supply means for sending the liquid phase refrigerant from the condenser to the water pump via the third passage during boiling cooling of the internal combustion engine;
During the boiling cooling of the internal combustion engine, when the liquid level of the liquid phase refrigerant of the gas-liquid separator becomes less than the first reference value, the liquid phase refrigerant from the capacitor is caused to pass through the second passage. Refrigerant replenishing means for sending to the gas-liquid separator;
During boiling cooling of the internal combustion engine, when the liquid level of the liquid-phase refrigerant of the gas-liquid separator becomes equal to or higher than a second reference value that is larger than the first reference value, the gas-liquid separator is separated. Refrigerant leakage means for sending liquid phase refrigerant to the capacitor via the fourth passage;
A boiling cooling device comprising:

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