Vehicle-mounted refrigeration equipment

Abstract

To provide vehicle-mounted refrigeration equipment enabling heat generated in the equipment to be efficiently utilized for heating the inside of a vehicle.SOLUTION: Vehicle-mounted refrigeration equipment comprises: a refrigeration machine 10 which includes a compressor 11 compressing a refrigerant, a heat exchanger 12 exchanging heat between the refrigerant and a heating medium heating the blown air, a condenser 13 exchanging heat between the refrigerant and outside air from outside a freezer, a condenser fan 13a blowing the outside air toward the condenser, and an evaporator 16 exchanging heat between the refrigerant and the air inside the freezer; and a control device 20 that controls the operation of the compressor and the condenser fan, and switches the operation of the refrigeration machine. The operation modes include a refrigeration operation for cooling the interior of the freezer, and a heating assist operation using a part of the heat generated by the refrigeration machine in the heating operation of a vehicle air conditioning device. When performing the heating assist operation, the control device reduces the rotational speed of the compressor and reduces the rotational speed of the condenser fan compared to a case in which the refrigeration operation is performed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a vehicle-mounted refrigeration device. [Background technology]

[0002] Conventionally, a refrigeration device is known that includes a refrigerant circuit including a compressor, a condenser, an electronic expansion valve, and an evaporator, and in which a refrigerant circulates through the refrigerant circuit (see, for example, Patent Document 1). When used as a heat pump, this refrigeration device superheats the external heat medium to a desired temperature by exchanging heat in the condenser between an external heat medium supplied from outside the refrigeration device and the refrigerant circulating through the refrigerant circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-210054 A Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors have considered heating an external heat medium with heat generated by the operation of an on-board refrigeration device mounted on a refrigerated vehicle that cools the inside of a freezer, and using the heat of the heated external heat medium to heat the vehicle cabin. The on-board refrigeration device is equipped with a refrigeration cycle including a refrigerant circuit, a compressor that compresses the refrigerant, a condenser that condenses the refrigerant by heat exchange between the refrigerant compressed by the refrigerant and outside air, an expansion valve that expands the refrigerant, and an evaporator that exchanges heat between the refrigerant and the air in the freezer and absorbs heat from the air in the freezer.

[0005] Specifically, in order to utilize the heat of the vehicle-mounted refrigeration unit for heating the vehicle interior, the inventors considered adding a heat exchanger between the compressor and the condenser, which heats the external heat medium by heat exchange between the high-temperature refrigerant discharged from the compressor and the external heat medium.The inventors then considered using the heat generated by the vehicle-mounted refrigeration unit via the external heat medium for heating the vehicle interior by heat exchange between the external heat medium heated by the heat exchanger and the blown air blown into the vehicle interior by the vehicle air conditioner to heat the blown air.

[0006] Incidentally, when the heat generated by the vehicle-mounted refrigeration device via the external heat medium is used to heat the vehicle interior, it is necessary to heat the external heat medium in the heat exchanger to a temperature that can heat the vehicle interior. The temperature that can heat the vehicle interior is higher than the outside air temperature and higher than the set temperature that is set when heating, for example, about 50°C to 60°C. Therefore, for example, when the external heat medium is heated to 60°C by the heat exchanger, the refrigerant discharged from the compressor and heat-exchanged with the external heat medium needs to be 60°C or higher. Therefore, in the vehicle-mounted refrigeration device, the compressor needs to increase the pressure of the refrigerant so that the temperature of the refrigerant discharged from the compressor is 60°C or higher.

[0007] In contrast, when the heat generated by the vehicle refrigeration device is not used to heat the vehicle interior and the vehicle refrigeration device is used only to cool the freezer, the vehicle refrigeration device does not need to compress the refrigerant until the temperature of the refrigerant discharged from the compressor reaches the heating temperature, and therefore, when the vehicle refrigeration device is used only to cool the freezer, the rotation speed of the compressor is suppressed compared to when the heat generated by the vehicle refrigeration device is used to heat the vehicle interior.

[0008] Therefore, when the vehicle refrigeration unit is used only for cooling the freezer, the pressure of the refrigerant discharged from the compressor is lower and the flow rate of the refrigerant through the refrigerant circuit is smaller than when the heat generated by the vehicle refrigeration unit is used for heating the vehicle cabin, and the energy consumption of the compressor is smaller when the vehicle refrigeration unit is used only for cooling the freezer, compared to when the heat generated by the vehicle refrigeration unit is used for heating the vehicle cabin.

[0009] That is, when the heat generated by the vehicle refrigeration device is used to heat the vehicle interior, the pressure of the refrigerant discharged from the compressor needs to be increased compared to when only cooling the freezer, which may result in a large energy consumption by the compressor. In other words, when the heat generated by the vehicle refrigeration device is used to heat the vehicle interior, the refrigeration capacity of the vehicle refrigeration device needs to be increased to a level equal to or higher than that required to cool the freezer. As a result, when the heat generated by the vehicle refrigeration device is used to heat the vehicle interior, the flow rate of the refrigerant circulating through the refrigerant circuit becomes larger compared to when only cooling the freezer.

[0010] Furthermore, when a heat exchanger for exchanging heat between the refrigerant and an external heat medium is added, the refrigerant is condensed by exchanging heat with the external heat medium in the heat exchanger in addition to being condensed by exchanging heat with the outside air in the condenser. Therefore, the condensation performance of the vehicle-mounted refrigeration device is improved compared to a configuration without the addition of a heat exchanger, and the heat absorption performance of the evaporator is improved with the improved condensation performance. And when the heat absorption performance of the evaporator is improved, the refrigeration capacity of the vehicle-mounted refrigeration device is increased, and the amount of decrease per unit time when cooling the inside of the freezer is increased.

[0011] For example, when an in-vehicle refrigeration device cools a freezer, the compressor stops operating when the temperature inside the freezer reaches a set temperature or lower, and then resumes operating when the temperature inside the freezer rises by a specified temperature after the compressor has stopped. In this case, if the amount of temperature drop per unit time when cooling the freezer increases, the time it takes for the temperature inside the freezer to reach the set temperature or lower will decrease. This will increase the frequency at which the compressor stops operating, and the operating rate of the in-vehicle refrigeration device will decrease.

[0012] When the compressor is not operating, the compressor does not discharge high-temperature, high-pressure refrigerant. Therefore, the refrigerant and the external heat medium cannot be exchanged in the heat exchanger to heat the external heat medium. Therefore, if the heat absorption performance of the evaporator increases by adding a heat exchanger and the operating rate of the vehicle-mounted refrigeration device decreases, the frequency of the compressor stopping operation increases, and the amount of heat transferred to the blown air when the heat generated by the vehicle-mounted refrigeration device is used to heat the vehicle interior decreases. Therefore, the heat generated by the vehicle-mounted refrigeration device cannot be used efficiently to heat the vehicle interior.

[0013] An object of the present disclosure is to provide an in-vehicle refrigeration device capable of efficiently using generated heat to heat the interior of a vehicle cabin. [Means for solving the problem]

[0014] According to one aspect of the disclosure, In an on-board refrigeration device that is mounted on a vehicle having a freezer and an on-board air conditioner, a refrigerator (10) including a compressor (11) that compresses and discharges a refrigerant, a heating heat exchanger (12) that exchanges heat between the refrigerant discharged from the compressor and a heat medium that heats air blown by a vehicle air conditioner, a condenser (13) that exchanges heat between the refrigerant that has passed through the heating heat exchanger and outside air outside the freezer, a condenser fan (13a) that blows outside air toward the condenser, and an evaporator (16) that exchanges heat between the refrigerant that has passed through the condenser and the air inside the freezer; a control device (20) that controls the operation of the compressor and the condenser fan and switches the operation mode of the refrigerator; The driving mode is The system includes a freezing operation for cooling the inside of the freezer, and a heating assist operation for cooling the inside of the freezer and exchanging heat between the refrigerant and the heat medium in the heating heat exchanger, thereby utilizing a part of the heat generated by the refrigerator for the heating operation of the vehicle air conditioner, When the heating assist operation is performed, the control device reduces the rotation speed of the compressor and reduces the rotation speed of the condenser fan, compared to when the freezing operation is performed.

[0015] According to this, by reducing the rotation speed of the compressor, the energy consumption of the compressor during the heating assist operation can be reduced, and the flow rate of the refrigerant flowing through the refrigerator can be reduced. Also, by reducing the rotation speed of the condenser fan 13a, the condensing performance of the refrigerator can be reduced, and the increase in enthalpy when the evaporator evaporates the refrigerant can be reduced. This reduces the refrigeration capacity of the refrigerator, and therefore the operating rate of the refrigerator can be increased.

[0016] Therefore, heat can be easily conducted from the vehicle refrigeration unit to the vehicle air conditioning unit, and the heat generated by the refrigeration unit can be efficiently used to heat the vehicle interior.

[0017] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic configuration diagram of an in-vehicle refrigeration device according to a first embodiment. [Diagram 2] 1 is a block diagram showing a control device for an in-vehicle refrigeration unit according to a first embodiment; [Diagram 3] 4 is a flowchart showing a flow of control executed by the control device according to the first embodiment. [Figure 4] FIG. 11 is a diagram for comparing the operation of a compressor, a condenser fan, and an evaporator fan in a refrigeration operation and a heating assist operation. [Diagram 5] FIG. 4 is a Mollier diagram showing the relationship between the state of refrigerant and the amount of heat transfer when the vehicle-mounted refrigeration device performs a refrigeration operation and when the vehicle-mounted refrigeration device does not perform a heating assist operation. [Figure 6] FIG. 4 is a Mollier diagram showing the relationship between the state of the refrigerant and the amount of heat transfer when the vehicle-mounted refrigeration device performs a heating assist operation and when the vehicle-mounted refrigeration device does not perform a heating assist operation. [Figure 7] 10 is a graph showing the relationship between the operating rate of the refrigerator and the heat transfer ratio when the vehicle refrigeration device does not perform a heating assist operation. [Figure 8] 4 is a graph showing the relationship between the operating rate of the refrigerator and the heat transfer ratio when the vehicle refrigeration device performs a heating assist operation. [Figure 9] FIG. 6 is a schematic configuration diagram of an in-vehicle refrigeration device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, the embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same reference numerals are used for parts that are the same as or equivalent to those described in the preceding embodiments, and the description thereof may be omitted. In addition, in the embodiments, when only a part of the components is described, the components described in the preceding embodiments can be applied to the other parts of the components. In the following embodiments, each embodiment can be partially combined with each other, even if not specifically stated, as long as it does not cause any trouble in combination.

[0020] (First embodiment) This embodiment will be described with reference to Figs. 1 to 8. The vehicle-mounted refrigeration device 1 of this embodiment is mounted on a refrigerated vehicle having a generator that converts power generated by an engine, which is a power source (not shown), into electric power, a battery that stores the power generated by the generator, a freezer for storing cargo, and a vehicle air conditioner that conditions the air inside the vehicle. The vehicle-mounted refrigeration device 1 is a cooling device that cools the air inside the freezer by operating using either the power of the engine or the power stored in the battery as a power source. As shown in Fig. 1, the vehicle-mounted refrigeration device 1 has a refrigerator 10 and a control device 20 that controls various devices that constitute the refrigerator 10.

[0021] The refrigerator 10 is configured with a vapor compression refrigeration cycle, and cools the air in the freezer by adjusting the temperature inside the freezer to a set temperature. The refrigerator 10 supplies heat generated in the refrigeration cycle device to water, which is a heat medium circulating in a hot water circuit 40 described later, of the vehicle air conditioner, so that part of the heat generated in the refrigeration cycle can be used to heat the vehicle interior. The refrigerator 10 is configured to be able to switch between operation modes described later. The operation mode of the refrigerator 10 can be switched by a control device 20 connected to the refrigerator 10 between an operation mode for cooling the freezer interior and an operation mode for cooling the freezer interior and also for using part of the heat generated in the refrigeration cycle device to heat the vehicle interior.

[0022] First, the refrigerator 10 will be described.

[0023] The refrigerator 10 includes a compressor 11 that compresses the refrigerant, a water-refrigerant heat exchanger 12 that exchanges heat between the refrigerant and water, a condenser 13 that dissipates heat from the refrigerant, a receiver 14 that stores surplus refrigerant, an expansion valve 15 that reduces the pressure of the refrigerant flowing out from the condenser 13, and an evaporator 16 that evaporates the reduced pressure refrigerant.

[0024] The refrigerator 10 uses a fluorocarbon refrigerant as a refrigerant, and configures a vapor compression subcritical refrigeration cycle in which the pressure of the refrigerant discharged from the compressor 11 does not exceed the critical pressure of the refrigerant. The refrigerant is mixed with lubricating oil that lubricates each sliding part inside the compressor 11. A part of the lubricating oil circulates in the refrigeration cycle together with the refrigerant. The refrigerant may be carbon dioxide or an HFO refrigerant, for example, R1234yf.

[0025] The compressor 11 is composed of an electric compressor having a fixed-capacity compression mechanism with a fixed discharge capacity and an electric motor (not shown) that drives the compression mechanism. The compressor 11 is configured to be able to compress the refrigerant by driving the compression mechanism in accordance with the rotation of the electric motor controlled by the control device 20. The pressure and temperature of the refrigerant discharged from the compressor 11 are adjusted by adjusting the rotation speed of the electric motor. A water-refrigerant heat exchanger 12 is connected to the refrigerant discharge side of the compressor 11. The high-temperature, high-pressure refrigerant compressed by the compressor 11 is discharged to the water-refrigerant heat exchanger 12.

[0026] Further, a refrigerant pressure sensor 11a that detects the pressure of the refrigerant discharged from the compressor 11 is provided on the outlet side of the compressor 11. As shown in Fig. 2, the refrigerant pressure sensor 11a is electrically connected to the control device 20 and transmits a detection signal corresponding to the pressure of the refrigerant discharged from the compressor 11 to the control device 20. In this embodiment, the refrigerant pressure sensor 11a functions as a refrigerant pressure detection unit.

[0027] The water-refrigerant heat exchanger 12 is a heating heat exchanger that exchanges heat between the high-temperature, high-pressure refrigerant discharged from the compressor 11 and the water circulating in the hot water circuit 40 to condense the refrigerant and heat the water. The water-refrigerant heat exchanger 12 has a refrigerant passage (not shown) through which the high-temperature, high-pressure refrigerant discharged from the compressor 11 flows, and a water passage (not shown) through which the water circulating in the hot water circuit 40 flows. The compressor 11 is connected to the inlet side of the refrigerant passage of the water-refrigerant heat exchanger 12. In addition, the inlet side of the condenser 13 is connected to the outlet side of the refrigerant passage of the water-refrigerant heat exchanger 12.

[0028] Condenser 13 is configured to condense the refrigerant and release heat by causing the refrigerant that has passed through the refrigerant passage of water-refrigerant heat exchanger 12 to flow inside condenser 13, thereby exchanging heat between the refrigerant and outside air that is the air outside the freezer. Condenser 13 is also provided with a condenser fan 13a.

[0029] Condenser fan 13a is disposed at a position facing condenser 13 and is disposed so as to be able to discharge air heated by a heat exchanger with the refrigerant to the outside of the vehicle by blowing outside air from outside the freezer to condenser 13. Condenser fan 13a is electrically connected to control device 20 as shown in Fig. 2, and the rotation speed of condenser fan 13a is controlled by a control signal input from control device 20. An expansion valve 15 is connected to the refrigerant outlet side of condenser 13 via receiver 14.

[0030] The receiver 14 is a liquid storage unit that stores surplus refrigerant to accommodate load fluctuations in the refrigeration cycle. The receiver 14 separates and stores gas refrigerant and liquid refrigerant. The receiver 14 is provided between the condenser 13 and the expansion valve 15.

[0031] The expansion valve 15 is a mechanical expansion valve whose throttling amount changes depending on the temperature of the inflowing refrigerant, and is configured to reduce pressure and expand the refrigerant flowing in from the condenser 13. Note that the expansion valve 15 may be an electric expansion valve whose throttling amount can be adjusted by a control signal input from the control device 20.

[0032] The evaporator 16 is configured to be capable of cooling the air passing through the evaporator 16 by evaporating the low-temperature, low-pressure refrigerant flowing in from the expansion valve 15 and causing the low-pressure refrigerant to exert a heat absorbing effect. The evaporator 16 is provided in the freezer and is a cooler that cools the inside of the freezer by heat exchange between the low-temperature, low-pressure refrigerant and the air in the freezer. The compressor 11 is connected to the refrigerant outlet side of the evaporator 16. In addition, an evaporator fan 16a is provided in addition to the evaporator 16.

[0033] The evaporator fan 16a is disposed at a position facing the evaporator 16, and is disposed so that the air that has passed through the evaporator 16 and been cooled can be blown into the freezer by blowing air to the evaporator 16. The evaporator fan 16a also circulates the cooled air in the freezer so that the temperature in the freezer becomes uniform. As shown in FIG. 2, the evaporator fan 16a is electrically connected to the control device 20, and the rotation speed of the evaporator fan 16a is controlled by a control signal input from the control device 20. The internal temperature made uniform by the evaporator fan 16a is detected by an internal temperature sensor 30 installed in the freezer.

[0034] The inside-compartment temperature sensor 30 is installed, for example, on the upstream side of the air flow of the evaporator 16, and is arranged so as to be able to measure the inside-compartment temperature by measuring the temperature of the air introduced into the evaporator 16. The inside-compartment temperature sensor 30 is connected to the control device 20 as shown in Fig. 2, and transmits a detection signal to the control device 20 according to the detected inside-compartment temperature.

[0035] Next, the hot water circuit 40 will be described.

[0036] As shown in FIG. 1, the hot water circuit 40 includes a water pump 41 that pumps water, which is a heat medium, a water-refrigerant heat exchanger 12 that heats the water by exchanging heat between the refrigerant and the water, and a heater core 42 that heats the blown air to be blown into the vehicle cabin by exchanging heat between the water heated by the water-refrigerant heat exchanger 12 and the blown air.

[0037] In addition, the hot water circuit 40 is configured such that water is circulated between the water-refrigerant heat exchanger 12 and the heater core 42 by a water pump 41. The heat medium circulating through the hot water circuit 40 may be a medium other than water, for example, a gas such as air. The hot water circuit 40 is connected to a vehicle air conditioner having an air conditioning refrigeration cycle (not shown). The hot water circuit 40 is configured to be capable of conducting a part of the heat generated by the refrigerator 10 to the air blown into the vehicle cabin in which the occupants are riding, via the refrigerant and water, when the vehicle air conditioner heats the vehicle cabin.

[0038] The water pump 41 is a pump that pumps water to the inlet side of the water passage of the water-refrigerant heat exchanger 12. An electric pump whose rotation speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 20 is used as the water pump 41. The water pump 41 adjusts the amount of heat transferred from the refrigerator 10 by adjusting the rotation speed. The water pump 41 operates when the vehicle air conditioner heats the passenger compartment.

[0039] The heater core 42 is a heating heat exchanger that heats the blown air by exchanging heat between the water heated in the water-refrigerant heat exchanger 12 and the blown air. The heater core 42 is disposed, for example, in an air conditioning case (not shown) of a vehicle air conditioner, and exchanges heat between the blown air blown from the air conditioning case toward the interior of the vehicle cabin and the water. The inlet side of the heater core 42 is connected to the outlet side of the water circuit of the water-refrigerant heat exchanger 12. The outlet side of the heater core 42 is also connected to the water pump 41 and the inlet side of the water circuit of the water-refrigerant heat exchanger 12.

[0040] The water-refrigerant heat exchanger 12 functions as a heating heat exchanger that transfers heat from the high-temperature, high-pressure refrigerant discharged from the compressor 11 to the blown air passing through the heater core 42 via the water circulating in the hot water circuit 40, thereby heating the air.

[0041] In addition, a water temperature sensor 42a is provided on the outlet side of the heater core 42 to detect the temperature of the water that has passed through the heater core 42. The water temperature sensor 42a is electrically connected to the control device 20 as shown in FIG. 2, and transmits a detection signal corresponding to the temperature of the water that has passed through the heater core 42 to the control device 20.

[0042] Next, the control device 20 will be described.

[0043] The control device 20 is composed of a well-known microcomputer including a CPU, a ROM, and a RAM and its peripheral circuits, and controls the operation of the components of the vehicle-mounted refrigeration device 1 based on a control program stored in the ROM or the like and input information. The control device 20 switches the operation mode of the refrigerator 10 between an operation mode for cooling the inside of the freezer and an operation mode for cooling the inside of the freezer and using part of the heat generated in the refrigeration cycle device for heating the inside of the vehicle, depending on whether the vehicle air conditioner performs heating or not. Hereinafter, the operation mode for only cooling the inside of the freezer is also called cooling operation, and the operation mode for cooling the inside of the freezer and using part of the heat generated by the refrigerator 10 for heating the inside of the vehicle is also called heating assist operation. The control device 20 switches the operation mode between either the freezing operation or the heating assist operation, depending on whether or not the occupant has input an operation for heating operation of the vehicle air conditioner, for example.

[0044] The freezing operation and the heating assist operation are operation modes in which the controller 20 controls the refrigerator 10 so that the inside temperature becomes the set temperature. In the freezing operation and the heating assist operation, the controller 20 controls the operation of the compressor 11 so that the inside temperature approaches the set temperature by controlling the electric motor of the compressor 11. The controller 20 controls the compressor 11 based on a detection signal transmitted from the inside temperature sensor 30 according to the temperature inside the freezer.

[0045] Furthermore, in the heating assist operation, the controller 20 controls the operation of the compressor 11 and the condenser fan 13a so that the inside temperature approaches the set temperature and the heat generated by the refrigerator 10 can be used for heating. The controller 20 controls the compressor 11 and the condenser fan 13a based on a detection signal corresponding to the pressure of the refrigerant transmitted from the refrigerant pressure sensor 11a.

[0046] The set temperature inside the freezer is a temperature set by the user and stored in advance in the control device 20, and the operation of the compressor 11 during normal operation and heating assist operation is determined based on the set temperature. The set temperature is set to a different temperature depending on the load stored in the freezer; for example, if the load is frozen food, the set temperature is set to -20°C, etc., and if the load is fresh food, the set temperature is set to 5°C, etc.

[0047] Next, the operation of the vehicle-mounted refrigeration device 1 executed by the control device 20 will be described with reference to the flow chart shown in FIG.

[0048] The vehicle-mounted refrigeration device 1 starts operation when an engine key switch (not shown) is turned on and power is supplied from a generator or a battery, and stops operation when the engine key switch is turned off and power supply from the generator or the battery is stopped. When the engine key switch is turned on, the control device 20 starts operation of various control devices of the refrigeration machine 10. Specifically, in step S10 shown in Fig. 3, the control device 20 starts operation of the electric motor of the compressor 11, the condenser fan 13a, and the evaporator fan 16a.

[0049] The compressor 11 drives a compression mechanism by rotating an electric motor, sucks in a low-temperature, low-pressure refrigerant, compresses it, and discharges a high-temperature, high-pressure refrigerant. The high-temperature, high-pressure refrigerant discharged from the compressor 11 flows to the water-refrigerant heat exchanger 12 and the condenser 13. The refrigerant pressure sensor 11a transmits a detection signal to the control device 20 according to the pressure of the refrigerant discharged from the compressor 11 and before it flows into the water-refrigerant heat exchanger 12.

[0050] When the vehicle-mounted refrigeration device 1 performs a freezing operation, the refrigerant that has flowed into the water-refrigerant heat exchanger 12 passes through the water-refrigerant heat exchanger 12 without exchanging heat with water. In contrast, when the vehicle-mounted refrigeration device 1 performs a heating assist operation, the refrigerant that has flowed into the water-refrigerant heat exchanger 12 heats the water by exchanging heat with water that is pumped by the water pump 41 and flows through the hot water circuit 40. The refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the condenser 13.

[0051] The refrigerant that flows into the condenser 13 dissipates heat by exchanging heat with the air outside the freezer blown by the condenser fan 13a. The refrigerant that has dissipated heat by the condenser 13 flows into the expansion valve 15, where it is decompressed and expanded, and flows into the evaporator 16. The refrigerant that flows into the evaporator 16 absorbs heat from the air inside the freezer blown by the evaporator fan 16a, evaporates, and is then sucked into the compressor 11 again. The air passing through the evaporator 16 is cooled by the latent heat of evaporation of the refrigerant. The evaporator fan 16a blows the air cooled by the evaporator 16 into the freezer, thereby cooling the entire air inside the freezer, and agitating the air so that the entire temperature inside the freezer is uniform. The inside temperature sensor 30 detects the inside temperature that has been uniformized by the evaporator fan 16a, and transmits a detection signal according to the detected inside temperature to the control device 20.

[0052] Next, in step S12, the control device 20 determines whether the heating operation of the vehicle air conditioner is on. For example, when the vehicle air conditioner is performing a heating operation to heat the vehicle interior, the control device 20 receives a signal from the vehicle air conditioner indicating that the heating operation is being performed.

[0053] When the control device 20 determines in step S12 that the heating operation of the vehicle air conditioner is not on, the control device 20 proceeds to step S20 and executes the refrigeration operation. On the other hand, when the control device 20 determines in step S12 that the heating operation of the vehicle air conditioner is on, the control device 20 proceeds to step S30 and executes the heating assist operation.

[0054] When the freezing operation is performed, the control device 20 controls the compressor 11, the condenser fan 13a, and the evaporator fan 16a based on a detection signal transmitted from the inside temperature sensor 30.

[0055] Specifically, in step S20, the controller 20 determines whether the internal temperature is lower than an off-determination temperature, which is a temperature lower than the set temperature by a predetermined first hysteresis temperature a°C. If the controller 20 does not determine that the internal temperature is lower than the off-determination temperature, in step S22, the controller 20 continues the operation of the compressor 11, the condenser fan 13a, and the evaporator fan 16a. That is, the controller 20 continues the operation of the compressor 11, the condenser fan 13a, and the evaporator fan 16a to cool the inside of the freezer until the internal temperature becomes lower than the off-determination temperature.

[0056] On the other hand, when the controller 20 determines that the internal temperature is lower than the off-determination temperature, in step S24, the controller 20 stops the operation of the compressor 11, the condenser fan 13a, and the evaporator fan 16a. That is, when the internal temperature drops to a temperature lower than the off-determination temperature, the controller 20 stops the operation of the compressor 11, the condenser fan 13a, and the evaporator fan 16a to stop cooling inside the freezer.

[0057] Next, in step S26, the controller 20 determines whether the internal temperature is higher than an on-determination temperature, which is a temperature higher than the set temperature by a predetermined second hysteresis temperature b°C. If the controller 20 does not determine that the internal temperature is higher than the on-determination temperature, the controller 20 keeps the compressor 11, condenser fan 13a, and evaporator fan 16a in a stopped state. In other words, the controller 20 stops the operation of the compressor 11, condenser fan 13a, and evaporator fan 16a until the internal temperature becomes higher than the on-determination temperature.

[0058] On the other hand, when the controller 20 determines that the internal temperature is higher than the on-criteria temperature, in step S28, the controller 20 starts the operation of the compressor 11, the condenser fan 13a, and the evaporator fan 16a. That is, when the internal temperature rises to a temperature higher than the on-criteria temperature, the controller 20 resumes the operation of the compressor 11, the condenser fan 13a, and the evaporator fan 16a to cool the inside of the freezer again.

[0059] In this manner, when the internal temperature falls to the OFF judgment temperature, the control device 20 of this embodiment stops the operation of the compressor 11, the condenser fan 13a, and the evaporator fan 16a. Then, when the internal temperature rises to the ON judgment temperature, the control device 20 resumes the operation of the compressor 11, the condenser fan 13a, and the evaporator fan 16a.

[0060] The first hysteresis temperature a°C for setting the OFF judgment temperature is set to a predetermined hysteresis width (for example, 1°C). The second hysteresis temperature b°C for setting the ON judgment temperature is set to a predetermined hysteresis width (for example, 1°C). The hysteresis width of the first hysteresis temperature a°C and the hysteresis width of the second hysteresis temperature b°C may be equal to each other or may be different from each other.

[0061] Furthermore, if the occupant performs an input operation for the heating operation of the vehicle air conditioner and it is determined in step S12 that the heating operation of the vehicle air conditioner is on, the control device 20 proceeds to the process of step S30 and executes the heating assist operation.

[0062] When an input operation for the heating operation of the vehicle air conditioner is performed, the control device 20 starts the operation of the water pump 41. As a result, the refrigerant discharged from the compressor 11 and flowing into the water-refrigerant heat exchanger 12 is pumped by the water pump 41 and exchanges heat with the water flowing through the hot water circuit 40, thereby heating the water. The water heated by the refrigerant exchanges heat with the blown air in the heater core 42, thereby heating the blown air. The heated blown air is then blown toward the inside of the vehicle cabin.

[0063] When the heating assist operation is performed, the controller 20 controls the compressor 11, the condenser fan 13a and the evaporator fan 16a based on detection signals transmitted from the refrigerant pressure sensor 11a, the internal temperature sensor 30 and the water temperature sensor 42a.

[0064] First, in step S30, the control device 20 reduces the rotation speed of the electric motor of the compressor 11 compared to the number of times when the refrigeration operation is performed. Specifically, the control device 20 sets the rotation speed of the electric motor of the compressor 11 to a minimum value. The minimum value of the rotation speed of the electric motor is a design value that is set in advance, and is set to the smallest value among values ​​that can circulate the lubricating oil together with the refrigerant in the refrigeration cycle, even when the rotation speed of the electric motor is reduced. Hereinafter, the rotation speed of the electric motor of the compressor 11 will be simply referred to as the rotation speed of the compressor 11.

[0065] Then, in step S32, the control device 20 stops the operation of the condenser fan 13a. As a result, in the heating assist operation, the condensation performance when the condenser 13 condenses the refrigerant is reduced compared to the refrigeration operation. Also, the pressure of the refrigerant discharged from the compressor 11 increases.

[0066] Next, in step S34, the control device 20 determines whether the saturation temperature of the refrigerant discharged from the compressor 11 is higher than a compressor determination temperature, which is a temperature that is a predetermined heating temperature α°C higher than a discharge temperature t°C, which is the temperature of the water that has passed through the heater core 42. A saturation temperature characteristic map, which is a relationship between the saturation temperature of the refrigerant and the pressure of the refrigerant, is experimentally set in advance in the control device 20. The control device 20 then determines the saturation temperature of the refrigerant discharged from the compressor 11 from this saturation temperature characteristic map and the detection signal transmitted from the refrigerant pressure sensor 11a.

[0067] Furthermore, the control device 20 determines the discharge temperature t° C. of the water that has passed through the heater core 42 based on the detection signal transmitted from the water temperature sensor 42a. In step S34, the control device 20 determines whether the saturation temperature of the refrigerant determined from the detection signal of the refrigerant pressure sensor 11a is higher than a compressor determination temperature that is set based on the discharge temperature t° C. determined from the detection signal of the water temperature sensor 42a. The refrigerant pressure sensor 11a functions as a saturation temperature detection unit that outputs a detection signal corresponding to the saturation temperature of the refrigerant discharged from the compressor 11.

[0068] When the control device 20 determines in step S34 that the saturation temperature of the refrigerant is higher than the compressor determination temperature, the control device 20 maintains the operating state of the compressor 11 and the condenser fan 13a and proceeds to the process of step S38.

[0069] On the other hand, if the control device 20 does not determine in step S34 that the saturation temperature of the refrigerant is higher than the compressor judgment temperature, in step S36, the control device 20 increases the rotation speed of the compressor 11 while maintaining the operating state of the condenser fan 13a. Specifically, in step S36, the control device 20 increases the rotation speed of the compressor 11 by a preset predetermined increase value. The control device 20 repeats the processes of steps S34 and S36 until it is determined that the saturation temperature of the refrigerant is higher than the compressor judgment temperature, and when it is determined that the saturation temperature of the refrigerant is higher than the compressor judgment temperature, the control device 20 proceeds to the process of step S38. That is, the control device 20 gradually increases the rotation speed of the compressor 11 by the preset increase value until the saturation temperature of the refrigerant becomes higher than the compressor judgment temperature, which is the target temperature.

[0070] Here, the compressor judgment temperature will be explained. When heat is supplied from the refrigerant to the water in the water-refrigerant heat exchanger 12, the refrigerant discharged from the compressor 11 and flowing in the refrigerant passage of the water-refrigerant heat exchanger 12 needs to be heated to a higher temperature than the temperature of the water discharged from the water pump 41 and flowing in the water passage of the water-refrigerant heat exchanger 12. When the heat generated by the refrigerator 10 is used to heat the vehicle interior, the heater core 42 needs to exchange heat between the water heated by the heat supplied from the refrigerant and the blown air passing through the heater core 42, and heat the blown air to a temperature that can be heated. For this reason, the compressor 11 needs to heat the temperature of the water that passes through the water-refrigerant heat exchanger 12 and flows to the heater core 42 through the refrigerant discharged from the compressor 11 to a temperature that can be heated. The temperature of the water that can be heated is, for example, 60° C., which is very high compared to the outside air temperature.

[0071] Furthermore, the water that has exchanged heat with the blown air in the heater core 42 is cooled compared to before flowing into the heater core 42 and discharged from the heater core 42. The amount of change in temperature of the water cooled in the heater core 42 can be determined in advance based on the cooling performance of the heater core 42, etc. For example, water that has a temperature of 60°C before flowing into the heater core 42 is cooled to approximately 55°C by heat exchange with the blown air in the heater core 42. In this way, when the temperature of the water before flowing into the heater core 42 can be determined based on the temperature of the water discharged from the heater core 42, the temperature of the water flowing into the heater core 42 can be determined based on the detection signal of the water temperature sensor 42a.

[0072] As described above, the compressor 11 of this embodiment needs to heat the temperature of the water flowing into the heater core 42, which can be calculated based on the discharge temperature t°C of the water discharged from the heater core 42, to a temperature that can be used for heating, by the water-refrigerant heat exchanger 12. That is, the compressor 11 needs to raise the temperature of the refrigerant discharged by itself to a temperature that can be used for heating the blown air that is heat exchanged with the water in the heater core 42. For this reason, in this embodiment, the refrigerant discharged from the compressor 11 needs to be heated to a temperature equal to or higher than the discharge temperature t°C of the water discharged from the heater core 42.

[0073] In order for the refrigerant discharged from the compressor 11 to exchange heat with the water discharged from the heater core 42 in the water-refrigerant heat exchanger 12 and to sufficiently heat the water, it is necessary to set the saturation temperature of the refrigerant discharged from the compressor 11 higher than the discharge temperature t°C. For this reason, the compressor determination temperature is set to a temperature that is higher than the discharge temperature t°C by a heating temperature α°C. The heating temperature α°C is set with a predetermined hysteresis width (for example, 15°C) taking into consideration that the refrigerant is cooled before reaching the water-refrigerant heat exchanger 12 from the compressor 11.

[0074] Returning to FIG. 3, in step S40, the control device 20 determines whether the pressure of the refrigerant discharged from the compressor 11 is lower than a predetermined determination threshold value P, based on the detection signal transmitted from the refrigerant pressure sensor 11a.

[0075] When the control device 20 determines in step S40 that the pressure of the refrigerant discharged from the compressor 11 is lower than the predetermined determination threshold value P, the control device 20 maintains the operating state of the compressor 11 and the condenser fan 13a and proceeds to the process of step S44.

[0076] On the other hand, when the control device 20 does not determine in step S40 that the pressure of the refrigerant discharged from the compressor 11 is lower than the predetermined judgment threshold P, in step S42, the control device 20 increases the rotation speed of the condenser fan 13a while maintaining the operating state of the compressor 11. Specifically, in step S42, the control device 20 increases the rotation speed of the condenser fan 13a by a predetermined set increase value that is set in advance. The control device 20 repeatedly executes the processes of steps S40 and S42 until it is determined that the pressure of the refrigerant discharged from the compressor 11 is lower than the predetermined judgment threshold P, and when it is determined that the pressure of the refrigerant is lower than the predetermined judgment threshold P, the control device 20 proceeds to the process of step S44. That is, the control device 20 gradually increases the rotation speed of the condenser fan 13a by each predetermined set increase value until the pressure of the refrigerant becomes lower than the predetermined judgment threshold P.

[0077] The predetermined judgment threshold value P is set to prevent an excessive increase in the refrigerant pressure due to stopping of condenser fan 13a, which increases the pressure of the refrigerant discharged from compressor 11 by stopping condenser fan 13a in step S32. The predetermined judgment threshold value P is set in advance in control device 20 as a maximum allowable value for the refrigerant pressure that increases due to stopping of condenser fan 13a.

[0078] When the controller 20 determines in step S40 that the refrigerant pressure is lower than the predetermined determination threshold value P, the controller 20 maintains the operating state of the condenser fan 13a in step S44. Then, the controller 20 executes the processes of steps S46 to S54.

[0079] In the processing of steps S46 to S54, when the inside temperature falls to the OFF judgment temperature, the control device 20 stops the operation of the compressor 11, the condenser fan 13a, and the evaporator fan 16a. Then, when the inside temperature rises to the ON judgment temperature, the control device 20 resumes the operation of the compressor 11, the condenser fan 13a, and the evaporator fan 16a. The processing of steps S46 to S54 is similar to the processing of steps S20 to S28 described in the refrigeration operation, and therefore a detailed description thereof will be omitted.

[0080] As described above, the operation of the evaporator fan 16a is the same in the freezing operation and the heating assist operation, but the operation of the compressor 11 and the condenser fan 13a is different. Specifically, as shown in Fig. 4, in the freezing operation, the rotation speed of the compressor 11 is controlled according to the difference between the inside temperature and the set temperature. In contrast, in the heating assist operation, the rotation speed of the compressor 11 is controlled according to the difference between the saturation temperature and the discharge temperature, and then the rotation speed is controlled so as to gradually increase according to the difference between the inside temperature and the set temperature.

[0081] In addition, the condenser fan 13a operates at a constant rotation speed during the freezing operation. The rotation speed of the condenser fan 13a during the freezing operation is set to, for example, the maximum rotation speed. In contrast, the compressor 11 is controlled so that the rotation speed gradually increases according to the pressure of the refrigerant after the operation is temporarily stopped during the heating assist operation.

[0082] Next, the effects of the vehicle-mounted refrigeration system 1 of this embodiment in which the compressor 11 and the condenser fan 13a are operated in this manner during heating assist operation will be described with reference to Figures 5 to 8. Note that the Mollier diagram M shown in Figures 5 and 6 shows the relationship between the state of the refrigerant and the amount of heat transfer when the vehicle-mounted refrigeration system 1 is operating.

[0083] Specifically, the Mollier diagram M shown by the solid line in Fig. 5 indicates the compression process, condensation process, decompression process, and evaporation process of the vapor compression refrigeration cycle when the vehicle refrigeration device 1 performs the refrigeration operation. Also, the Mollier diagram M shown by the solid line in Fig. 6 indicates the compression process, condensation process, decompression process, and evaporation process of the vapor compression refrigeration cycle when the vehicle refrigeration device 1 performs the heating assist operation. And the Mollier diagram M shown by the dashed line in Fig. 5 and Fig. 6 indicates the compression process, condensation process, decompression process, and evaporation process of the vapor compression refrigeration cycle in the case where the rotation speed of the compressor 11 and the condenser fan 13a is not reduced when the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle cabin. Note that the horizontal axis in Fig. 5 and Fig. 6 indicates the enthalpy of the refrigerant, and the vertical axis indicates the pressure of the refrigerant.

[0084] In the Mollier diagram M shown by the solid line and the dashed line in Fig. 5 and Fig. 6, the portion from point A to point B and the portion from point A' to point B' indicate the change in enthalpy of the refrigerant that increases during the compression process in which the refrigerant is compressed by the compressor 11, and the change in pressure of the refrigerant. In the Mollier diagram M shown by the solid line in Fig. 5, the portion from point B to point C indicates the change in enthalpy of the refrigerant that decreases during the condensation process in which the refrigerant is condensed by the condenser 13. In the Mollier diagram M shown by the dashed line in Fig. 5, the portion from point B' to point E', and in the Mollier diagram M shown by the solid line and the dashed line in Fig. 6, the portion from point B to point E and the portion from point B' to point E' indicate the change in enthalpy of the refrigerant that decreases during the condensation process in which the refrigerant is condensed by the water-refrigerant heat exchanger 12. In the Mollier diagram M shown by the solid and dashed lines in Figure 5, the portion heading from point E' to point C', and in the Mollier diagram M shown by the solid and dashed lines in Figure 6, the portion heading from point E to point C and the portion heading from point E' to point C' show the change in enthalpy of the refrigerant that decreases due to the condensation process in which the refrigerant is condensed by condenser 13.

[0085] 5 and 6, the portions from point C to point D and from point C' to point D' indicate the change in refrigerant pressure that decreases due to the decompression process in which the refrigerant is decompressed by expansion valve 15. In the Mollier diagrams M shown by solid and dashed lines in Fig. 5 and 6, the portions from point D to point A and from point D' to point A' indicate the change in refrigerant enthalpy that increases due to the evaporation process in which the refrigerant is evaporated by evaporator 16.

[0086] Here, with reference to FIG. 5, we will explain the difference in Mollier diagram M between the case where the vehicle refrigeration device 1 performs refrigeration operation and the case where the vehicle air conditioner does not perform heating assist operation when heating, and the rotation speeds of the compressor 11 and the condenser fan 13a are not reduced.

[0087] When the heat generated in the vehicle refrigeration device 1 is used to heat the vehicle interior by conducting the heat to the hot water circuit 40 of the vehicle air conditioner via water, it is necessary to heat the water in the water-refrigerant heat exchanger 12 to a temperature at which heating is possible, for example, about 60° C. For this reason, it is necessary to increase the pressure of the refrigerant so that the temperature of the refrigerant discharged from the compressor 11 becomes 60° C. or higher.

[0088] In contrast, when the vehicle-mounted refrigeration device 1 is used only for cooling the inside of the freezer, the vehicle-mounted refrigeration device 1 does not need to compress the refrigerant so that the temperature of the refrigerant discharged from the compressor 11 is 60° C. or higher. Specifically, when the vehicle-mounted refrigeration device 1 is used only for cooling the inside of the freezer, the vehicle-mounted refrigeration device 1 compresses the refrigerant so that the temperature of the refrigerant discharged from the compressor 11 is slightly higher than the outside air temperature, for example, when the outside air temperature is 5° C., the refrigerant temperature is 10° C. Therefore, when the heat generated by the vehicle-mounted refrigeration device 1 is used to heat the inside of the vehicle cabin, the rotation speed of the compressor 11 needs to be higher than when the vehicle-mounted refrigeration device 1 is operated in refrigeration mode.

[0089] Therefore, when the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle interior, the pressure and enthalpy of the refrigerant discharged from the compressor 11 increase compared to when the vehicle refrigeration device 1 is operated in refrigeration mode, as shown in Fig. 5. That is, the pressure and enthalpy of the refrigerant at point B' are greater than those at point B, respectively.

[0090] Furthermore, when the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle interior, the flow rate per unit time of the refrigerant circulating through the refrigeration cycle is increased by increasing the rotation speed of the compressor 11, compared to when the vehicle refrigeration device 1 is operated in refrigeration mode. As a result, when the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle interior, the energy consumption of the compressor 11 is greater, compared to when the vehicle refrigeration device 1 is operated in refrigeration mode. In other words, when the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle interior, the required energy consumption of the compressor 11 is greater, compared to when the vehicle refrigeration device 1 is operated in refrigeration mode.

[0091] 5, by exchanging heat between the refrigerant and water in the water-refrigerant heat exchanger 12, the amount of decrease in enthalpy of the refrigerant caused by the condensation process in the refrigeration cycle is greater than in a configuration in which heat exchange between the refrigerant and water is not performed in the water-refrigerant heat exchanger 12. That is, the enthalpy of the refrigerant at point C' is smaller than the enthalpy of the refrigerant at point C.

[0092] Therefore, the vehicle refrigeration unit 1 has higher condensation performance than a configuration in which heat exchange between the refrigerant and water is not performed in the water-refrigerant heat exchanger 12, and accordingly, the increase in enthalpy of the refrigerant caused by the evaporation process is larger. That is, the increase in enthalpy from point D' to point A' is larger than the increase in enthalpy from point D to point A.

[0093] Here, if the flow rate of the refrigerant circulating through the refrigeration cycle is the refrigerant flow rate Gr, and the change in enthalpy in the evaporation process is the enthalpy change ΔI, the refrigeration capacity Q of the refrigerator 10 can be calculated by the following formula 1.

[0094] (Number 1) Refrigeration capacity Q = Refrigerant flow rate Gr × Enthalpy change ΔI As described above, the refrigerant flow rate Gr when the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle interior is increased as the rotation speed of the compressor 11 increases, compared to when the vehicle refrigeration device 1 is operated in the freezing operation. Also, the enthalpy change amount ΔI when the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle interior is increased as the condensation performance of the water-refrigerant heat exchanger 12 increases, compared to when the vehicle refrigeration device 1 is operated in the freezing operation. Therefore, the refrigeration capacity Q when the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle interior is increased as compared to when the vehicle refrigeration device 1 is operated in the freezing operation. In this way, when the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle interior, the refrigeration capacity Q of the refrigerator 10 increases to or above the refrigeration capacity Q required only to cool the inside of the freezer.

[0095] As described above, when the vehicle-mounted refrigeration device 1 cools the inside of the freezer, the compressor 11 stops operating when the inside temperature drops to the OFF judgment temperature, and resumes operating when the inside temperature rises to the ON judgment temperature. Therefore, when the refrigeration capacity Q of the refrigerator 10 increases, the time from when the inside temperature rises to the ON judgment temperature and the compressor 11 starts operating to when the inside temperature drops to the OFF judgment temperature and the compressor 11 stops operating becomes shorter. In other words, the operating time of the compressor 11 when cooling the inside of the freezer becomes shorter, and the operating rate of the refrigerator 10 decreases.

[0096] When the compressor 11 is not operating, the compressor 11 does not discharge high-temperature, high-pressure refrigerant. Therefore, the refrigerant and water cannot be exchanged in the water-refrigerant heat exchanger 12 to heat the water. Therefore, if the water-refrigerant heat exchanger 12 is added to use the heat generated in the vehicle refrigeration device 1 for heating the vehicle interior, and the condensation performance of the refrigerator 10 is increased, causing a decrease in the operating rate of the refrigerator 10, it becomes difficult to transfer heat from the vehicle refrigeration device 1 to the hot water circuit 40 of the vehicle air conditioner. Therefore, the heat generated in the vehicle refrigeration device 1 cannot be used efficiently for heating the vehicle interior.

[0097] 7 shows a graph illustrating the relationship between the operating rate of the chiller 10 and the heat transfer ratio when heat is transferred from the vehicle-mounted refrigeration device 1 to the hot water circuit 40. The operating rate of the chiller 10 is calculated by dividing the thermal load, which is the amount of heat transferred from the outside of the freezer to the inside of the freezer, by the refrigeration capacity Q of the chiller 10. In addition, the heat transfer ratio when heat is transferred from the vehicle-mounted refrigeration device 1 to the hot water circuit 40 is proportional to the operating rate of the chiller 10. When the chiller 10 operates at an operating rate of 100% without the compressor 11 being stopped, the heat transfer ratio from the vehicle-mounted refrigeration device 1 to the hot water circuit 40 is 1.0.

[0098] As shown in FIG. 7, when the heat generated by the vehicle-mounted refrigeration device 1 is used to heat the vehicle cabin, the operating rate of the refrigeration unit 10 decreases, and the heat transfer ratio decreases compared to when the vehicle-mounted refrigeration device 1 is operated in refrigeration mode.

[0099] In contrast to this, the difference in the Mollier diagram M and the difference in the heat transfer amount ratio when the heating assist operation is performed will be described with reference to Figs. 6 and 8.

[0100] As described above, in this embodiment, when the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle interior, the heating assist operation is performed to set the rotation speed of the compressor 11 to a minimum value. This makes it possible to reduce the energy consumption of the compressor 11 compared to when the heating assist operation is not performed and the rotation speed of the compressor 11 is not reduced. Furthermore, as the rotation speed of the compressor 11 is reduced, the refrigerant flow rate Gr becomes smaller compared to when the heating assist operation is not performed.

[0101] When the heat generated by the vehicle refrigeration device 1 is used to heat the vehicle interior, the heating assist operation is performed to stop the condenser fan 13a. This increases the pressure of the refrigerant discharged from the compressor 11 in the refrigeration cycle, making it easier to increase the saturation temperature of the refrigerant discharged from the compressor 11 even if the rotation speed of the compressor 11 is reduced.

[0102] Furthermore, by stopping condenser fan 13a, the condensation performance of condenser 13 decreases compared to when condenser fan 13a is not stopped by not performing the heating assist operation. In the refrigeration cycle, the supercooled portion, which is a region with smaller enthalpy than the refrigerant saturated liquid line, i.e., subcooling, can be suppressed.

[0103] Therefore, as shown in Fig. 6, the change in enthalpy of the refrigerant that decreases due to the condensation process in which the refrigerant is condensed by the condenser 13 becomes smaller. That is, the amount of decrease in enthalpy from point E to point C is smaller than the amount of decrease in enthalpy from point E' to point C'. Accordingly, in the vehicle refrigeration device 1 of this embodiment, the increase in the enthalpy of the refrigerant that increases due to the evaporation process becomes smaller than when the heating assist operation is not performed. That is, the amount of enthalpy change ΔI from point D to point A is smaller than the amount of enthalpy change ΔI from point D' to point A'.

[0104] Therefore, the refrigeration capacity Q of the vehicle-mounted refrigeration device 1 of this embodiment is smaller than when the heating assist operation is not performed. As a result, compared to when the heating assist operation is not performed, the time from when the inside temperature rises to the ON judgment temperature and the compressor 11 starts to operate until the inside temperature drops to the OFF judgment temperature and the compressor 11 stops operating is longer. That is, the operating time of the compressor 11 when cooling the inside of the freezer is longer, and the operating rate of the refrigerator 10 is increased. As a result, the frequency of the operation stop of the compressor 11 is reduced, and the frequency of the water-refrigerant heat exchanger 12 to heat the water by exchanging heat between the high-temperature and high-pressure refrigerant discharged from the compressor 11 and the water can be increased. This makes it easier to conduct heat from the vehicle-mounted refrigeration device 1 to the hot water circuit 40 of the vehicle air conditioner. Then, the heat generated by the vehicle-mounted refrigeration device 1 can be efficiently used to heat the vehicle interior.

[0105] The difference in the operating rate of the chiller 10 and the heat transfer ratio when transferring heat from the vehicle-mounted refrigeration device 1 to the hot water circuit 40 between when the heating assist operation is performed and when the heating assist operation is not performed will be explained with reference to FIG. 8.

[0106] 8, when the heating assist operation is performed, the operating rate of the refrigerator 10 increases, and the heat transfer ratio increases compared to when the heating assist operation is not performed. Therefore, the heat generated by the vehicle-mounted refrigeration device 1 can be efficiently used to heat the vehicle interior.

[0107] As described above, when performing heating assist operation, the control device 20 of the vehicle-mounted refrigeration device 1 of this embodiment reduces the rotation speed of the compressor 11 and also reduces the rotation speed of the condenser fan 13a compared to when performing refrigeration operation.

[0108] According to this, by lowering the rotation speed of the compressor 11, it is possible to reduce the energy consumption of the compressor 11 when the heating assist operation is performed, and also to reduce the refrigerant flow rate Gr.

[0109] Furthermore, by reducing the rotation speed of the condenser fan 13a, the condensing performance of the refrigerator 10 is reduced, and the increase in enthalpy in the evaporation process can be reduced. This reduces the refrigeration capacity Q of the refrigerator 10, and the operating rate of the refrigerator 10 can be increased. This makes it easier to conduct heat from the vehicle-mounted refrigeration device 1 to the hot water circuit 40 of the vehicle air conditioner, and the heat generated by the refrigerator 10 can be used efficiently to heat the vehicle interior.

[0110] Furthermore, even if the rotation speed of compressor 11 is reduced, the pressure of the refrigerant discharged from compressor 11 can be increased by stopping condenser fan 13a, making it easier to increase the saturation temperature of the refrigerant discharged from compressor 11. Therefore, even in heating assist operation, which requires a higher temperature than the temperature of the refrigerant discharged from compressor 11 compared to refrigeration operation, it is easier to increase the temperature of the refrigerant discharged from compressor 11 to this high temperature.

[0111] Furthermore, according to the above embodiment, the following effects can be obtained.

[0112] (1) In the above embodiment, when the operation mode is switched to the heating assist operation, the control device 20 sets the set value of the rotation speed of the compressor 11 to the minimum value.

[0113] This allows the energy consumption of the compressor 11 to be reduced, compared to when the rotation speed of the compressor 11 is not set to the minimum value.

[0114] (2) In the above embodiment, the compressor 11 includes a refrigerant pressure sensor 11a that outputs a detection signal corresponding to the saturation temperature of the refrigerant discharged from the compressor 11. After setting the rotation speed of the compressor 11 to a minimum value, if the saturation temperature is lower than the compressor determination temperature, the control device 20 increases the rotation speed of the compressor 11 until the saturation temperature becomes higher than the compressor determination temperature.

[0115] According to this, even if the temperature of the refrigerant discharged from the compressor 11 is high during the heating assist operation, the temperature of the refrigerant can be quickly raised to this high temperature.

[0116] (3) In the above embodiment, when the operation mode is switched to the heating assist operation, the control device 20 stops the operation of the condenser fan 13a.

[0117] This allows the condensation performance of refrigerator 10 to be reduced and the increase in enthalpy in the evaporation process to be reduced, compared to when condenser fan 13a is not stopped. This reduces the refrigeration capacity Q of refrigerator 10, compared to when condenser fan 13a is not stopped, and therefore the operating rate of refrigerator 10 can be increased.

[0118] Therefore, heat can be more easily conducted from the vehicle refrigeration device 1 to the hot water circuit 40 of the vehicle air conditioner, and the heat generated by the refrigerator 10 can be used more efficiently to heat the vehicle interior.

[0119] (4) In the above embodiment, there is provided a refrigerant pressure sensor 11a that outputs a detection signal corresponding to the pressure of the refrigerant discharged from compressor 11. After stopping the operation of condenser fan 13a, if the refrigerant pressure is higher than determination threshold P, control device 20 increases the rotation speed of condenser fan 13a until the refrigerant pressure becomes lower than determination threshold P.

[0120] Stopping condenser fan 13a increases the pressure of the refrigerant discharged from compressor 11, so there is a risk that stopping condenser fan 13a will cause the pressure of the refrigerant discharged from compressor 11 to increase excessively.

[0121] In contrast, according to the present embodiment, the pressure of the refrigerant discharged from the compressor 11 can be prevented from increasing excessively.

[0122] Second embodiment Next, a second embodiment will be described with reference to Fig. 9. This embodiment differs from the first embodiment in that a heat pump 43 and a heating pump 44 are added to the hot water circuit 40 of the vehicle air conditioner. The rest is the same as the first embodiment. Therefore, in this embodiment, the differences from the first embodiment will be mainly described, and the description of the same parts as the first embodiment may be omitted.

[0123] As shown in Fig. 9, the hot water circuit 40 of the vehicle control device of this embodiment is provided with a heat pump 43. The heat pump 43 is a heating heat exchanger that heat exchanges between a heating refrigerant that exchanges heat with the high-temperature, high-pressure refrigerant discharged from the compressor 11 and water discharged from a heater core 42, thereby heating the water. The heat pump 43 is provided between the water-refrigerant heat exchanger 12 and the heater core 42, and is arranged so that heat generated in the vehicle-mounted refrigeration device 1 can be conducted to the heater core 42 via the heating refrigerant.

[0124] A heating refrigerant pipe 45 through which the heating refrigerant circulates is provided between the heat pump 43 and the water-refrigerant heat exchanger 12, allowing the heating refrigerant to circulate between the heat pump 43 and the water-refrigerant heat exchanger 12. A heating pump 44 for circulating the heating refrigerant is provided in the heating refrigerant pipe 45. In addition, a water pipe 46 through which water circulates is provided between the heat pump 43 and the heater core 42, allowing the water to circulate between the heat pump 43 and the heater core 42.

[0125] The heat pump 43 has a heating refrigerant passage through which a heating refrigerant that exchanges heat with the high-temperature, high-pressure refrigerant discharged from the compressor 11 flows, and a heating water passage through which water discharged from the heater core 42 flows.

[0126] The heating pump 44 is a pump that circulates the heating refrigerant between the water-refrigerant heat exchanger 12 and the heat pump 43. The heating pump 44 is an electric pump whose rotation speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 20. The heating pump 44 operates when the vehicle air conditioner heats the vehicle cabin.

[0127] The refrigerant used for heating may be the same as the refrigerant circulating through the refrigerator 10, or a different refrigerant may be used.

[0128] In this embodiment, a water pump 41 and a water temperature sensor 42a are provided in the water piping 46. The water pump 41 circulates water between the heater core 42 and the heat pump 43. The water temperature sensor 42a outputs a detection signal to the control device 20 according to the temperature of the water discharged from the heater core 42 and before it flows into the heat pump 43.

[0129] In the hot water circuit 40 of the vehicle air conditioner configured as above, when an input operation for heating operation of the vehicle air conditioner is performed, the control device 20 starts the operation of the water pump 41 and the heating pump 44. Then, the high-temperature, high-pressure refrigerant discharged from the compressor 11 exchanges heat with the heating refrigerant circulating in the heating refrigerant pipe 45 in the refrigerant passage of the water-refrigerant heat exchanger 12, thereby heating the heating refrigerant.

[0130] Furthermore, the heating refrigerant heated by the refrigerant discharged from the compressor 11 exchanges heat with water flowing through a heating water passage of the heat pump 43 in a heating refrigerant passage of the heat pump 43, thereby heating the water. Then, the water heated by the refrigerant discharged from the compressor 11 via the heat pump 43 exchanges heat with the blown air in the heater core 42, thereby heating the blown air. Then, the heated blown air is blown toward the inside of the vehicle cabin.

[0131] Other configurations are the same as those of the first embodiment. The vehicle-mounted refrigeration device 1 of this embodiment can obtain the same effects as those of the first embodiment, which are achieved by a configuration similar to or equivalent to those of the first embodiment.

[0132] (Other embodiments) Representative embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments and can be modified in various ways, for example, as described below.

[0133] In the above embodiment, an example has been described in which the control device 20 sets the set value of the rotation speed of the compressor 11 to the minimum value when the operation mode is switched to the heating assist operation, but the present invention is not limited to this.

[0134] For example, when the operation mode is switched to heating assist operation, the control device 20 may set the set value of the rotation speed of the compressor 11 to a set value different from the minimum value, as long as the set value is a rotation speed that can be reduced compared to when refrigeration operation is performed.

[0135] In the above embodiment, an example has been described in which the control device 20 increases the rotation speed of the compressor 11 when the saturation temperature is lower than the compressor judgment temperature until the saturation temperature becomes higher than the compressor judgment temperature, but the present invention is not limited to this.

[0136] For example, when the operation mode is switched to the heating assist operation, the control device 20 may set the set value of the rotation speed of the compressor 11 to the minimum value, and thereafter, maintain the rotation speed of the compressor 11 at the minimum value.

[0137] In the above embodiment, an example has been described in which the control device 20 stops the operation of the condenser fan 13a when the operation mode is switched to the heating assist operation, but the present invention is not limited to this.

[0138] For example, when the operation mode is switched to the heating assist operation, the control device 20 may rotate the condenser fan 13a at a lower rotation speed compared to when the freezing operation is performed.

[0139] In the above embodiment, an example has been described in which the control device 20 increases the rotation speed of the condenser fan 13a when the refrigerant pressure is higher than the judgment threshold P until the refrigerant pressure becomes lower than the judgment threshold P, but the present invention is not limited to this.

[0140] For example, when the operation mode is switched to the heating assist operation, the control device 20 may stop the operation of the condenser fan 13a, and thereafter, may keep the condenser fan 13a in the stopped state.

[0141] In the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where it is particularly expressly stated that they are essential or where they are clearly considered to be essential in principle.

[0142] In the above-described embodiments, when numerical values ​​such as the number, values, amounts, ranges, etc. of components of the embodiments are mentioned, they are not limited to the specific numbers unless it is specifically stated as required or unless it is clearly limited to a specific number in principle.

[0143] In the above-described embodiments, when referring to the shapes, positional relationships, etc. of components, etc., there is no limitation to those shapes, positional relationships, etc., unless specifically stated or in principle limited to a specific shape, positional relationship, etc.

[0144] The control device 20 and the method of the present disclosure may be implemented in a special-purpose computer provided by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. The control device 20 and the method of the present disclosure may be implemented in a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. The control device 20 and the method of the present disclosure may be implemented in one or more special-purpose computers configured with a combination of a processor and memory programmed to perform one or more functions and a processor configured with one or more hardware logic circuits. The computer program may also be stored in a computer-readable non-transitory tangible recording medium as instructions executed by the computer. [Explanation of symbols]

[0145] 10. Refrigeration Machine 11 Compressor 12 Heat exchanger for heating 13 Capacitor 13a Condenser Fan 16 Evaporator 20 Control device

Claims

1. In an on-board refrigeration device that is mounted on a vehicle having a freezer and an on-board air conditioner, a refrigerator (10) including: a compressor (11) that compresses and discharges a refrigerant; a heating heat exchanger (12) that exchanges heat between the refrigerant discharged from the compressor and a heat medium that heats air blown by the vehicle air conditioner; a condenser (13) that exchanges heat between the refrigerant that has passed through the heating heat exchanger and outside air outside the freezer; a condenser fan (13a) that blows the outside air toward the condenser; and an evaporator (16) that exchanges heat between the refrigerant that has passed through the condenser and the air inside the freezer; a control device (20) that controls the operation of the compressor and the condenser fan and switches the operation mode of the refrigerator; The operation mode is a refrigeration operation for cooling the inside of the freezer and a heating assist operation for cooling the inside of the freezer and exchanging heat between the refrigerant and the heat medium in the heating heat exchanger, thereby utilizing a part of the heat generated by the refrigerator for a heating operation of the vehicle air conditioner, The vehicle-mounted refrigeration device, when the heating assist operation is performed, the control device reduces the rotation speed of the compressor and reduces the rotation speed of the condenser fan compared to when the refrigeration operation is performed.

2. The control device includes:

2. The vehicle-mounted refrigeration device according to claim 1, wherein when the operation mode is switched to the heating assist operation, the set value of the rotational speed of the compressor is set to a minimum value.

3. a saturation temperature detection unit (11a) that outputs a detection signal corresponding to a saturation temperature of the refrigerant discharged from the compressor, The control device includes:

3. The vehicle-mounted refrigeration device according to claim 2, wherein, when the rotation speed of the compressor is set to the minimum value, if the saturation temperature is lower than a predetermined target temperature that is set based on the temperature of the heat medium that has exchanged heat with the blown air, the rotation speed of the compressor is increased until the saturation temperature becomes higher than the predetermined target temperature.

4. The control device includes: The vehicle-mounted refrigeration apparatus according to claim 1 , wherein when the operation mode is switched to the heating assist operation, the operation of the condenser fan is stopped.

5. a refrigerant pressure detection unit (11a) that outputs a detection signal corresponding to the pressure of the refrigerant discharged from the compressor; 5. The vehicle-mounted refrigeration device according to claim 4, wherein when the operation of the condenser fan is stopped, if the pressure of the refrigerant is higher than a predetermined threshold value that is set in advance, the control device increases a rotation speed of the condenser fan until the pressure of the refrigerant becomes lower than the predetermined threshold value.

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