Vehicle air conditioning system

Abstract

To provide an air conditioner for a vehicle that is able to avoid refrigerant stagnation in an evaporator.SOLUTION: An air conditioner 10 for absorbing heat from a motor 11 and using it for heating a cabin 12 comprises: a refrigerating cycle circuit 30 that circulates a refrigerant through: a chiller 35 that absorbs heat from the motor 11; a water-cooled condenser 32 that discharges heat to heat air to be blown into the vehicle cabin 12 during heating; and an evaporator 33 that cools air to be blown into the vehicle cabin 12 during cooling; and an inside / outside air switching door 22 that switches inside air circulation or outside air introduction of the air to be blown into the vehicle cabin 12. When an outside air temperature is equal to or lower than a predetermined temperature, a temperature of the evaporator 33 is equal to or lower than a predetermined temperature, and an amount of heat absorption from the motor 11 is equal to or larger than a predetermined amount of heat absorption, the inside / outside air switching door 22 circulates inside air to be blown into the vehicle cabin 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an air conditioner for a vehicle that absorbs heat from a heating element and uses the heat to heat a vehicle interior. [Background technology]

[0002] In some cases, a vehicle air conditioner absorbs heat from a heat source such as a motor, a battery, or an engine, and uses the heat to heat the vehicle interior. The vehicle air conditioner has a refrigeration cycle circuit that circulates a refrigerant through a chiller that absorbs heat from the heat source, a heat exchanger that exhausts heat to heat the air to be blown into the vehicle interior during heating, and an evaporator that cools the air to be blown into the vehicle interior during cooling. For example, Patent Document 1 discloses a vehicle air conditioner that absorbs heat from a motor using a chiller and uses the exhaust heat to heat the vehicle interior. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-053319 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned vehicle air conditioner, when outside air is introduced at an extremely low temperature during heating, the introduced outside air cools the evaporator provided in the air passage, causing the evaporator pressure to drop. Meanwhile, the chiller pressure rises due to heat absorption. As a result, the chiller pressure becomes higher than the evaporator pressure, causing refrigerant stagnation in the evaporator. Refrigerant stagnation is a phenomenon in which liquid refrigerant stagnates. When refrigerant stagnation occurs in the evaporator, the amount of refrigerant circulating becomes insufficient, causing a decrease in heating capacity.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an air conditioner for a vehicle that can prevent refrigerant stagnation in the evaporator. [Means for solving the problem]

[0006] The vehicle air conditioning system of the present invention is a vehicle air conditioning system that absorbs heat from a heating element and uses the heat to heat the passenger compartment, and is equipped with a chiller that absorbs heat from the heating element, a heat exchanger that exhausts heat to heat the air to be blown into the passenger compartment during heating, an evaporator that cools the air to be blown into the passenger compartment during cooling, a refrigeration cycle circuit that circulates refrigerant through the chiller and a switching unit that switches between internal air circulation or outside air introduction for the air to be blown into the passenger compartment, and is characterized in that during heating, when the outside air temperature is below a predetermined temperature, the temperature of the evaporator is below a predetermined temperature, and the amount of heat absorbed from the heating element is equal to or greater than the predetermined amount of heat absorption, the switching unit circulates the air to be blown into the passenger compartment as internal air. Effect of the Invention

[0007] According to the vehicle air conditioning system of the present invention, refrigerant stagnation in the evaporator can be avoided. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing an example of an air conditioning device for a vehicle according to an embodiment; [Diagram 2] 1 is a block diagram showing an example of an air conditioning device for a vehicle according to an embodiment; [Diagram 3] FIG. 4 is a flow chart showing a flow of inside air circulation control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An example of an embodiment of the present invention will be described in detail below. In the following description, specific shapes, materials, directions, values, etc. are merely examples for the purpose of easily understanding the present invention, and can be appropriately changed according to the application, purpose, specifications, etc. <Vehicle air conditioning system> An air conditioner 10 as one example of the embodiment will be described with reference to Figs. 1 and 2.

[0010] An air conditioner 10 as an air conditioner for a vehicle absorbs heat from a motor 11 as a heat source and uses the heat to heat a vehicle interior 12. The air conditioner 10 has a refrigeration cycle circuit 30 that circulates refrigerant through a chiller 35 that absorbs heat from the motor 11 via a motor cooling circuit 50, a water-cooled condenser 32 as a heat exchanger that exhausts heat to heat the air to be blown into the vehicle interior 12 during heating, and an evaporator 33 that cools the air to be blown into the vehicle interior 12 during cooling. The air conditioner 10 makes it possible to prevent refrigerant from stagnation in the evaporator 33, as will be described in detail later.

[0011] The air conditioner 10 is mounted on a vehicle. The vehicle is a four-wheeled electric vehicle, and is driven by a motor 11 that is driven by battery power. However, the vehicle is not limited to an electric vehicle, and may be, for example, a hybrid vehicle.

[0012] The heat generating element in this embodiment is the motor 11, which is cooled by a motor cooling circuit 50, the details of which will be described later. The heat generating element is not limited to the motor 11, and may be a battery, or, in the case of a hybrid vehicle, may be an engine.

[0013] As shown in FIG. 1, the air conditioner 10 has an air passage 20 for blowing conditioned air into the vehicle interior 12, the above-mentioned refrigeration cycle circuit 30, a heater circuit 40 for heating the air blown by the air passage 20, a motor cooling circuit 50 for cooling the motor 11, and an air conditioning ECU (Electronic Control Unit) 60 for controlling each of the devices in the air passage 20, the refrigeration cycle circuit 30, the heater circuit 40, and the motor cooling circuit 50.

[0014] The air passage 20 is a passage that conditions air and delivers the conditioned air to the vehicle interior 12. The air passage 20 includes a heater core 41 connected to a heater circuit 40 and that heats the air passing through the air passage 20, an evaporator 33 connected to a refrigeration cycle circuit 30 and that cools the air passing through the air passage 20, an inside / outside air switching door 22 as a switching unit that switches between inside air circulation and outside air introduction of air to be delivered to the vehicle interior 12, an air mix door 23 that switches between blowing air to the heater core 41 and blowing air to the evaporator 33, and a blower 24 that generates an air flow toward the vehicle interior 12.

[0015] The refrigeration cycle circuit 30 includes a compressor 31 that compresses a refrigerant, a water-cooled condenser 32 that is connected to a heater circuit 40 and serves as a heat exchanger that rejects heat to the cooling water circulating through the heater circuit 40, an evaporator 33 that is provided in the air passage 20 and cools the air passing through the air passage 20, an evaporator-side expansion valve 34 that adjusts the amount of refrigerant circulating to the evaporator 33, a chiller 35 that is connected to a motor cooling circuit 50 and absorbs heat from the cooling water circulating through the motor cooling circuit 50, and a chiller-side expansion valve 36 that adjusts the amount of refrigerant circulating to the chiller 35, all of which are connected by piping. The evaporator 33 is also provided with an evaporator temperature sensor 64 that detects the temperature of the evaporator 33.

[0016] In this embodiment, the heat exchanger that exhausts heat for use in heating is configured as the water-cooled condenser 32, but this is not limited to this. The heat exchanger may be a heater core, and the exhaust heat from the refrigerant may be directly used for heating without providing the heater circuit 40.

[0017] The heater circuit 40 realizes heating operation by circulating water heated by the water-cooled condenser 32 as a heat source and heating the air passing through the air passage 20 with the heater core 41. The heater circuit 40 has the water-cooled condenser 32 that heats the water circulating through the heater circuit 40, the heater core 41 that is provided in the air passage 20 and heats the air passing through the air passage 20, and a pump 42 that circulates the cooling water of the heater circuit 40.

[0018] The motor cooling circuit 50 circulates the cooling water cooled by the chiller 35 to cool the motor 11. The motor cooling circuit 50 has the chiller 35 that cools the cooling water circulating through the motor cooling circuit 50, a radiator 51 that cools the cooling water circulating through the motor cooling circuit 50, a motor cooler 52 that cools the motor 11, and a pump 53 that circulates the cooling water in the motor cooling circuit 50. In addition, a cooling water temperature sensor 65 that detects the temperature of the cooling water circulating through the motor cooling circuit 50 is provided at the inlet of the chiller 35.

[0019] The air conditioning ECU 60 controls each of the devices in the air passage 20, the refrigeration cycle circuit 30, the heater circuit 40, and the motor cooling circuit 50. The air conditioning ECU 60 executes inside air circulation control, which will be described in detail later, in the air conditioner 10. The air conditioning ECU 60 is a computer having a processor 61 with a CPU that performs information processing therein, and a memory 62 that stores software, programs, or data executed by the processor 61.

[0020] The air conditioning ECU 60 is connected to the inside / outside air switching door 22, the air mix door 23, and the blower 24 of the air passage 20, the compressor 31, the evaporator side expansion valve 34, and the chiller side expansion valve 36 of the refrigeration cycle circuit 30, the pump 42 of the heater circuit 40, and the pump 53 of the motor cooling circuit 50. The air conditioning ECU 60 is also connected to an outside air temperature sensor 63 that detects the outside air temperature, an evaporator temperature sensor 64 that detects the temperature of the evaporator 33, and a coolant temperature sensor 65 that detects the temperature of the coolant at the inlet of the chiller 35 of the motor cooling circuit 50.

[0021] 2, the air conditioning ECU 60 has a heating operation execution unit 71, an outside air temperature determination unit 72, an evaporator temperature determination unit 73, a chiller heat absorption amount determination unit 74, and an inside air circulation switching unit 75, each of which will be described in detail later. The heating operation execution unit 71, the outside air temperature determination unit 72, the evaporator temperature determination unit 73, the chiller heat absorption amount determination unit 74, and the inside air circulation switching unit 75 are realized by the processor 61 executing a program stored in the memory 62.

[0022] The heating operation execution unit 71 executes a heating operation in which heat is absorbed from the motor 11 and used to heat the vehicle interior 12. Specifically, in the refrigeration cycle circuit 30, the rotation speed of the compressor 31 is controlled to circulate the refrigerant, the opening of the chiller-side expansion valve 36 is adjusted to evaporate the refrigerant in the chiller 35 to absorb heat from the cooling water in the motor cooling circuit 50, and the refrigerant is condensed in the water-cooled condenser 32 to discharge heat to the circulating water in the heater circuit 40. Note that the evaporator-side expansion valve 34 is used during cooling, but is also used during heating and dehumidification operation during heating.

[0023] Furthermore, the heating operation execution unit 71 drives the pump 42 in the heater circuit 40 to circulate the circulating water, heats the heater core 41 with the exhaust heat of the water-cooled condenser 32, and heats the air passing through the air passage 20. Furthermore, in the motor cooling circuit 50, the pump 53 is driven to circulate the cooling water, and cools the motor cooler 52 with the heat absorption of the chiller 35 and the heat absorption of the radiator 51.

[0024] The outside air temperature determination unit 72 detects the outside air temperature from the outside air temperature sensor 63, and determines whether the outside air temperature is equal to or lower than a predetermined temperature.

[0025] An evaporator temperature determination unit 73 detects the evaporator temperature from the evaporator temperature sensor 64, and determines whether the evaporator 33 is at or below a predetermined temperature.

[0026] The chiller heat absorption amount determination unit 74 calculates the amount of heat absorption of the chiller 35 and determines whether the amount of heat absorption of the chiller 35 is equal to or greater than a predetermined amount. In this embodiment, the amount of heat absorption of the chiller 35 is calculated based on the temperature of the cooling water at the inlet of the chiller 35 of the motor cooling circuit 50 detected by the cooling water temperature sensor 65. The chiller heat absorption amount determination unit 74 may calculate the amount of heat absorption of the chiller 35 by estimating the motor cooling load based on the rotation speed of the compressor 31, or may calculate the amount of heat absorption of the chiller 35 by estimating the motor cooling load based on the output of the motor 11.

[0027] When heating operation is being performed, the outside air temperature at which cold air is introduced from outside to cool the evaporator 33 is below a predetermined temperature, the temperature of the evaporator 33 is below a predetermined temperature, and a pressure difference is generated between the evaporator 33 and the chiller 35, causing the refrigerant to become stagnant in the evaporator 33, and the heat absorption amount of the chiller 35 is equal to or greater than a predetermined heat absorption amount, the inside / outside air switching unit 75 prevents the evaporator 33 from being cooled by circulating the air blown into the passenger compartment 12 through the inside / outside air switching door 22 as inside air, thereby eliminating the pressure difference between the evaporator 33 and the chiller 35.

[0028] The internal air circulation switching unit 75 prevents a pressure difference between the evaporator 33 and the chiller 35 from occurring, causing the refrigerant to stagnate in the evaporator 33, and prevents a shortage of refrigerant circulation and a decrease in heating capacity.

[0029] <Interior air circulation control> The flow of the inside air recirculation control will be described with reference to FIG.

[0030] In step S11, it is confirmed whether or not a heating operation is being performed by the heating operation execution unit 71 in which heat is absorbed from the motor 11 and used to heat the vehicle interior 12. If the heating operation is being performed, the process proceeds to step S12.

[0031] In step S12, the outside air temperature determination unit 72 determines whether the outside air temperature is equal to or lower than a predetermined temperature. If the outside air temperature is equal to or lower than the predetermined temperature, the process proceeds to step S13. In step S12, it is preferable that the outside air temperature determination unit 72 provide hysteresis between the threshold value at which the outside air temperature is determined to be equal to or lower than the predetermined temperature and the threshold value at which the outside air temperature returns from a state at or below the predetermined temperature to a normal state (a state in which the outside air temperature is higher than the predetermined temperature).

[0032] In step S13, the evaporator temperature determination unit 73 determines whether the temperature of the evaporator 33 is equal to or lower than a predetermined temperature. If the temperature of the evaporator 33 is equal to or lower than the predetermined temperature, the process proceeds to step S14. In step S13, it is preferable that the evaporator temperature determination unit 73 provides hysteresis between the threshold value at which the temperature of the evaporator 33 is determined to be equal to or lower than the predetermined temperature and the threshold value at which the temperature of the evaporator 33 returns from a state at or below the predetermined temperature to a normal state (a state in which the temperature of the evaporator 33 is higher than the predetermined temperature).

[0033] In step S14, the chiller heat absorption amount determination unit 74 determines whether the amount of heat absorption by the chiller 35 is equal to or greater than a predetermined amount. If the amount of heat absorption by the chiller 35 is equal to or greater than the predetermined amount, the process proceeds to step S15. Note that in step S14, it is preferable for the chiller heat absorption amount determination unit 74 to provide hysteresis between the threshold value at which it is determined that the amount of heat absorption by the chiller 35 is equal to or greater than the predetermined amount, and the threshold value at which the amount of heat absorption by the chiller 35 returns from the state where the amount of heat absorption by the chiller 35 is equal to or greater than the predetermined amount to the normal state (a state where the amount of heat absorption by the chiller 35 is smaller than the predetermined amount).

[0034] In step S15, when a heating operation is performed in which heat is absorbed from the motor 11 and used to heat the passenger compartment 12, the outside air temperature at which cold air is introduced to cool the evaporator 33 is equal to or lower than a predetermined temperature, the temperature of the evaporator 33 is equal to or lower than a predetermined temperature, and the amount of heat absorbed by the chiller 35 at which a pressure difference occurs between the evaporator 33 and the chiller 35 and the refrigerant is expected to become sluggish in the evaporator 33 is equal to or higher than a predetermined amount of heat absorbed, the inside / outside air switching unit 75 causes the air to be blown into the passenger compartment 12 to be circulated inside the vehicle by the inside / outside air switching door 22. This prevents the evaporator 33 from being cooled, eliminates the pressure difference between the evaporator 33 and the chiller 35, and prevents the refrigerant from becoming sluggish in the evaporator 33.

[0035] <Effects> In the air conditioner 10 of this embodiment, a heating operation is performed in which heat is absorbed from the motor 11 and used to heat the vehicle interior 12. When outside air is introduced under extremely low temperature, the introduced outside air cools the evaporator 33 provided in the air passage 20, and the pressure of the evaporator 33 drops. Meanwhile, the pressure of the chiller 35 rises due to the absorption of heat. As a result, the chiller pressure becomes higher than the evaporator pressure, and refrigerant stagnation occurs in the evaporator 33. When refrigerant stagnation occurs in the evaporator 33, the amount of refrigerant circulating becomes insufficient, and the heating capacity drops.

[0036] Therefore, when a heating operation is performed in which heat is absorbed from the motor 11 and used to heat the passenger compartment 12, and the outside air temperature at which cold air is introduced to cool the evaporator 33 is below a predetermined temperature, the temperature of the evaporator 33 is below a predetermined temperature, and the amount of heat absorbed by the chiller 35 at which a pressure difference occurs between the evaporator 33 and the chiller 35 and the refrigerant is assumed to become stagnant in the evaporator 33 is equal to or greater than a predetermined amount, the air blown into the passenger compartment 12 is circulated inside by the inside / outside air switching door 22. This prevents the evaporator 33 from being cooled, eliminates the pressure difference between the evaporator 33 and the chiller 35, prevents the refrigerant from becoming stagnant in the evaporator 33, and avoids a decrease in heating capacity.

[0037] It should be noted that the present invention is not limited to the above-described embodiment and its modified examples, and various modifications and improvements are possible within the scope of the matters described in the claims of this application. [Explanation of symbols]

[0038] 10 air conditioner (vehicle air conditioner), 11 motor (heating element), 12 passenger compartment, 20 air passage, 22 inside / outside air switching door (switching unit), 23 air mix door, 24 blower, 30 refrigeration cycle circuit, 31 compressor, 32 water-cooled condenser (heat exchanger), 33 evaporator, 34 evaporator side expansion valve, 35 chiller, 36 chiller side expansion valve, 40 heater circuit, 41 heater core, 42 pump, 50 motor cooling circuit, 51 radiator, 52 motor cooler, 53 pump, 60 air conditioning ECU, 61 processor, 62 memory, 63 outside air temperature sensor, 64 evaporator temperature sensor, 65 coolant temperature sensor, 71 heating operation execution unit, 72 outside air temperature determination unit, 73 evaporator temperature determination unit, 74 Chiller heat absorption determination unit, 75 Internal air circulation switching unit

Claims

[Claim 1] An air conditioner for a vehicle that absorbs heat from a heating element and uses it to heat a vehicle interior, a chiller that absorbs heat from the heat generating element, a heat exchanger that removes heat in order to heat the air to be blown into the vehicle compartment during heating, and an evaporator that cools the air to be blown into the vehicle compartment during cooling; and a refrigeration cycle circuit that circulates a refrigerant through the chiller and the heat exchanger. a switching unit for switching between internal air circulation and external air introduction for air blown into the vehicle compartment; Equipped with the switching unit causes the air to be blown into the passenger compartment to be circulated inside the vehicle when the vehicle is in a heating mode, the outside air temperature is equal to or lower than a predetermined temperature, the temperature of the evaporator is equal to or lower than a predetermined temperature, and the amount of heat absorbed from the heating element is equal to or higher than a predetermined amount of heat absorbed. Vehicle air conditioning system.

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