JP7387322B2 - Vehicle air conditioner - Google Patents

Description

The present invention relates to a vehicle air conditioner applied to vehicles such as electric vehicles and hybrid vehicles.

In recent years, in the automobile industry, vehicles that run using electric motors, such as hybrid vehicles, plug-in hybrid vehicles, and electric vehicles (hereinafter referred to as "electric vehicles"), are aiming to achieve fuel efficiency in order to reduce _CO2 emissions. Research and development is underway. The air conditioner installed in an electric vehicle utilizes a heat pump cycle that allows heating operation even when the vehicle is running on electricity, where waste heat from the engine cannot be used.

An air conditioner using a heat pump system includes, for example, a compressor that compresses and discharges a refrigerant, and a heat radiator that functions as a condenser that is installed inside the vehicle interior and radiates heat from the refrigerant, as disclosed in Patent Document 1 below. a heat absorber installed inside the vehicle interior that functions as an evaporator that absorbs heat from the refrigerant; and an outdoor heat exchanger installed outside the vehicle interior that functions as an evaporator that absorbs heat from the refrigerant or a condenser that radiates heat from the ventilated outside air. The refrigerant circuit is equipped with a refrigerant circuit connected to the refrigerant. This air conditioner has a heating mode in which the refrigerant discharged from the compressor radiates heat in a radiator, and the refrigerant radiated in the radiator absorbs heat in an outdoor heat exchanger. ``Cooling mode'' in which heat is radiated in the exchanger and heat absorbed in the heat absorber; ``Dehumidification heating'' in which the refrigerant discharged from the compressor is radiated in the radiator, and the refrigerant radiated in the radiator is then absorbed in the heat absorber and the outdoor heat exchanger. It is possible to switch between various air conditioning modes, such as "Dehumidification/cooling mode" in which the refrigerant discharged from the compressor radiates heat in the radiator and outdoor heat exchanger and absorbs heat in the heat absorber.

In addition, the air conditioner of Patent Document 1 includes a circulation pump, a heat medium heating device (ECH), and a heating medium heating device (ECH) inside the vehicle interior as means for realizing an auxiliary heating function when the outside temperature is low (for example, 0° C. or lower). It is equipped with a heat medium circulation circuit including a heat medium-air heat exchanger provided in the air flow passage that is on the air upstream side of the radiator with respect to the air flow in the air flow passage through which the supplied air flows. . In this heat medium circulation circuit, a heat medium circulated by a circulation pump is heated by a heat medium heating device, and a heat medium-air heat exchanger provided in an air flow passage serves as a heater core to assist heating operation. .

Japanese Patent Application Publication No. 2016-107745

However, in conventional air conditioners including the device of Patent Document 1, when the outside temperature is extremely low, for example below -15°C, the mass flow rate compressed by the compressor decreases as the density of the refrigerant decreases. There is a problem that the capacity of the compressor is significantly reduced and normal heating operation cannot be performed.

In addition, in the case of conventional air conditioners, if the heater element of the heat medium heating device is driven at the maximum output (100%), the durability will deteriorate and may cause a failure. The drive is limited to about 50%.

For this reason, conventional air conditioners cannot perform normal heating operations when the outside temperature is extremely low, and the heating performance is low due to the limited output of the heat medium heating device, which reduces the environment inside the vehicle. It was difficult to keep it in good condition.

SUMMARY OF THE INVENTION The present invention aims to solve the conventional problems and provides an air conditioner for a vehicle that can improve heating performance while minimizing deterioration of durability of a heat medium heating device.

In order to achieve the above object, a vehicle air conditioner according to the present invention includes: an air flow path through which air to be supplied into a vehicle interior flows; a compressor that compresses a refrigerant; a radiator that radiates heat from the refrigerant; a refrigerant circuit including a heat absorber that absorbs heat from the refrigerant; an outdoor heat exchanger that is provided outside the vehicle interior and that radiates or absorbs heat from the refrigerant; a heat medium heating device that heats the heat medium; an auxiliary heating section that includes an airflow passage internal heat exchanger that radiates heat from the heat medium, and in which the heat medium heated by the heat medium heating device circulates; and an auxiliary heating section formed between the outdoor heat exchanger and the heat absorber. a heat medium-refrigerant heat exchanger that exchanges heat with the heat medium by causing the refrigerant that is branched and distributed from the first refrigerant flow path to absorb heat, and the control device controls air conditioning operation using the refrigerant circuit; an auxiliary heating execution determination unit that determines whether or not to add an auxiliary heating function; and an auxiliary heating execution determination unit that determines whether or not to add an auxiliary heating function; and when the auxiliary heating execution determination unit determines that it is necessary to add an auxiliary heating function, a drive control unit that drives the heat medium heating device by limiting its output to a predetermined output limit value or less. We are prepared.

Preferably, in the vehicle air conditioner, the output limit value may be set to 50% or less of the maximum output of the heat medium heating device.

Preferably, the vehicle air conditioner includes an outside temperature determination section that determines whether the outside temperature is below a predetermined temperature threshold, and the refrigerant circuit is connected to the radiator and the outdoor heat exchanger. The auxiliary heating section includes a third refrigerant flow path that branches from a second refrigerant flow path formed between the refrigerant flow path and the third refrigerant flow path that bypasses the outdoor heat exchanger and is connected to the first refrigerant flow path, and the auxiliary heating section includes: a first heat medium circulation circuit that causes the heat medium heated by the heat medium heating device to flow into the heat medium heating device again via the heat medium-refrigerant heat exchanger; The heat medium flowing out of the heat medium-refrigerant heat exchanger is caused to flow into the air flow passage heat exchanger, a second heat medium circulation circuit that causes the heat medium discharged from the internal heat exchanger to flow into the heat medium heating device again; If it is determined that the temperature is below the threshold value, the heat medium is circulated in the first heat medium circulation circuit, and in the heat medium-refrigerant heat exchanger, the heat medium circulating in the first heat medium circulation circuit is Heat may be exchanged between the heat medium and the refrigerant flowing into the refrigerant heat exchanger through the third refrigerant flow path.

Preferably, in the vehicle air conditioner, the drive control unit determines that the air conditioning operation execution determination unit is capable of performing air conditioning operation using the refrigerant circuit but does not perform air conditioning operation, or that the air conditioning operation is not performed using the refrigerant circuit. When it is determined that air conditioning operation cannot be performed, the output limit based on the output limit value of the heat medium heating device is canceled to heat the heat medium, and the heat medium is circulated in the second heat medium circulation circuit. , the air flowing through the airflow passage may be heated.

According to the present invention, heating performance can be improved while suppressing deterioration of durability of the heat medium heating device as much as possible.

1 is a schematic configuration diagram of a vehicle air conditioner showing an embodiment of the present invention. FIG. 2 is a block diagram showing a control system. FIG. 2 is a schematic configuration diagram of a vehicle air conditioner showing flow paths of a refrigerant and a heat medium in a first auxiliary heating mode. It is a schematic block diagram of the vehicle air conditioner which shows the flow path of a refrigerant|coolant and a heat medium in 2nd normal auxiliary heating mode. FIG. 2 is a schematic configuration diagram of a vehicle air conditioner showing flow paths of a refrigerant and a heat medium in a low-temperature auxiliary heating mode. FIG. 2 is a schematic configuration diagram of a vehicle air conditioner showing a flow path of a heat medium in an emergency auxiliary heating mode. It is a flowchart which shows the processing content when heating mode is selected.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
The embodiments shown here are exemplified to embody the technical idea of the present invention, and are not intended to limit the present invention. In addition, all other possible embodiments, embodiments, operational techniques, etc. that can be considered by those skilled in the art without departing from the gist of the present invention are included within the scope and gist of the present invention, and are not included in the scope of the claims. inventions and their equivalents.

Furthermore, for the convenience of illustration and ease of understanding, the drawings attached to this specification may be represented schematically by changing the scale, vertical/width dimensional ratio, shape, etc. from the actual thing as appropriate, but these are merely examples. However, this does not limit the interpretation of the present invention.

The vehicle air conditioner 1 of the present invention is applied to an electric vehicle such as a hybrid vehicle, a plug-in hybrid vehicle, or an electric vehicle that can be driven by the driving force of an electric motor.

In addition, in this specification, "temperature control target equipment" refers to a "battery", "electric motor", "inverter", "ECU (Electronic Control Unit)" that is mounted on an electric vehicle and used when driving or driving the vehicle. ), which can be a heat source that generates heat when driven (vehicle heat generating equipment), and whose temperature is adjusted by cooling or heating to an appropriate driving temperature. In this embodiment, an example will be described in which a "battery" is cooled as the temperature control target device 100.

[Device overview]
FIG. 1 is a diagram showing the configuration of a vehicle air conditioner 1 according to the present embodiment.
As shown in FIG. 1 or 2, a vehicle air conditioner 1 is a device that performs air conditioning (heating, cooling, dehumidification, and ventilation) in a vehicle interior. The vehicle air conditioner 1 includes an air conditioning unit 10 provided inside the vehicle interior, a refrigerant circuit 20 provided both inside and outside the vehicle interior, and an auxiliary heating unit 30 that cools the temperature control target device 100. The vehicle air conditioner 1 includes a control device 40 that performs overall drive control of each part that constitutes the vehicle air conditioner 1.

<Air conditioning unit>
The air conditioning unit 10 has an air flow path 11 for circulating air to be supplied into the vehicle interior.

One end side of the air flow passage 11 has an outside air intake port 12a for causing air outside the vehicle interior to flow into the air flow passage 11, and an inside air intake port 12b for causing air inside the vehicle interior to flow into the air flow passage 11. A suction port 12 is provided.

Furthermore, an inlet switching damper 13 is provided at one end of the airflow passage 11, and is capable of opening one of the outside air inlet 12a or the inside air inlet 12b and closing the other. Further, an indoor blower 14 such as a sirocco fan is provided at one end of the air flow passage 11 to circulate air from one end of the air flow passage 11 to the other end.

The other end of the air flow passage 11 is provided with an outlet for blowing out the air that has passed through the air flow passage 11 to a predetermined location within the vehicle interior. The air outlet includes a foot air outlet (not shown) that blows air toward the passenger's feet, a vent air outlet (not shown) that blows air toward the passenger's upper body, and an air outlet that blows air toward the interior side of the vehicle's windshield. A differential air outlet (not shown) is provided, and an air outlet switching damper (not shown) that switches the direction of air blowing from each air outlet is provided.

A heat absorber 15 for cooling and dehumidifying the air flowing through the air flow passage 11 is provided on the downstream side of the indoor blower 14 in the air flow direction in the air flow passage 11 . Furthermore, a heat radiator 16 for heating the air flowing through the air flow passage 11 is provided on the downstream side of the heat absorber 15 in the air flow direction in the air flow passage 11 .

The radiator 16 is disposed on one side of the air flow passage 11 in the orthogonal direction, and a bypass flow passage 11a that bypasses the radiator 16 is formed on the other side of the air flow passage 11 in the orthogonal direction. Between the heat absorber 15 and the heat radiator 16 in the air flow passage 11, the air volume ratio between the air that has passed through the heat absorber 15, the air that flows into the heat radiator 16, and the air that flows through the bypass flow passage 11a is adjusted. An air mix damper 17 is provided for this purpose. Note that the installation location of the radiator 16 is not limited to the air flow path 11, and may be placed outside the air conditioning unit 10.

The air mix damper 17 closes the upstream side of either the bypass flow passage 11a or the radiator 16 in the air flow direction and opens the other, or closes the upstream side of the bypass flow path 11a and the radiator 16, or opens the other side, according to the set operation mode (air conditioning mode, equipment cooling mode). By adjusting the opening degree of the vessel 16 on the upstream side in the air flow direction, both the bypass passage 11a and the radiator 16 are opened. The temperature of the conditioned air blown into the vehicle interior from the air conditioning unit 10 can be adjusted by adjusting the opening position of the air mix damper 17.

<Refrigerant circuit>
The refrigerant circuit 20 includes the above-mentioned heat absorber 15 and heat radiator 16, a compressor 21 for compressing the refrigerant, an outdoor heat exchanger 22 for exchanging heat between the refrigerant and the air outside the vehicle, and a fully closed and fully open circuit. An electronic expansion valve 23 (first expansion valve 23a, second expansion valve 23b, and third expansion valve 23c) whose opening degree can be adjusted between the two, and a solenoid valve for opening and closing the refrigerant flow path 24 (first solenoid valve 24a, second solenoid valve 24b), and check valve 25 (first check valve 25a, second check valve 25b) for regulating the flow direction of the refrigerant in the refrigerant flow path. , an accumulator 26 for separating gaseous refrigerant and liquid refrigerant and causing the gaseous refrigerant to be sucked into the compressor 21, and performing heat exchange between the refrigerant flowing in the refrigerant circuit 20 and the heat medium flowing in the auxiliary heating section 30. A heat medium-refrigerant heat exchanger 27 is provided. Each part constituting the refrigerant circuit 20 is connected to allow refrigerant to circulate through refrigerant flow passages 20a to 20g made of refrigerant pipes such as aluminum pipes and copper pipes. As the refrigerant flowing through the refrigerant circuit 20, for example, R-134a is used.

The outdoor heat exchanger 22 is arranged outside the vehicle interior, such as in the engine room, so that the flow direction of air that exchanges heat with the refrigerant is in the longitudinal direction of the vehicle. An outdoor blower 22a is provided near the outdoor heat exchanger 22 to circulate air outside the vehicle in the front and rear direction when the vehicle is stopped.

The refrigerant circuit 20 is formed with a refrigerant flow passage 20 a that connects the refrigerant discharge side of the compressor 21 and the refrigerant inflow side of the radiator 16 , and connects the refrigerant outlet side of the radiator 16 and the refrigerant of the outdoor heat exchanger 22 . A refrigerant flow path 20b (corresponding to a "second refrigerant flow path" in the claims) is formed to connect the inflow side. A first expansion valve 23a is provided in the refrigerant flow passage 20b.

The refrigerant circuit 20 is formed with a refrigerant flow path 20c (corresponding to the "first refrigerant flow path" in the claims) that connects the refrigerant outflow side of the outdoor heat exchanger 22 and the refrigerant inflow side of the heat absorber 15. has been done. A first check valve 25a and a second expansion valve 23b are provided in the refrigerant flow passage 20c in this order from the outdoor heat exchanger 22 side.

The refrigerant circuit 20 is formed with a refrigerant flow passage 20d that connects the refrigerant outflow side of the heat absorber 15 and the refrigerant suction side of the compressor 21. A second check valve 25b and an accumulator 26 are provided in the refrigerant flow path 20d in this order from the heat absorber 15 side.

In the refrigerant circuit 20, the outdoor heat exchanger 22 is bypassed, and the first check valve 25a and the second expansion valve in the refrigerant flow path 20c are connected between the radiator 16 and the first expansion valve 23a in the refrigerant flow path 20b. A refrigerant flow path 20e is formed to connect between the refrigerant flow path 20e and the refrigerant flow path 23b. A first electromagnetic valve 24a is provided in the refrigerant flow passage 20e.

In the refrigerant circuit 20, a refrigerant connecting between the heat absorber 15 and the first check valve 25b in the refrigerant flow path 20d is provided between the outdoor heat exchanger 22 and the first check valve 25a in the refrigerant flow path 20c. A flow path 20f (corresponding to the "fifth refrigerant flow path" in the claims) is formed. A second electromagnetic valve 24b is provided in the refrigerant flow path 20f.

In the refrigerant circuit 20, the first check valve 25a and the second expansion valve 23b are connected to the refrigerant inflow side of the heat medium-refrigerant heat exchanger 27, and the refrigerant outflow side of the heat medium-refrigerant heat exchanger 27 is connected to the refrigerant inflow side of the heat medium-refrigerant heat exchanger 27. A refrigerant flow path 20g is formed that connects the second check valve 25b and the accumulator 26 in the refrigerant flow path 20d from the side. A third expansion valve 23c is provided on the refrigerant inflow side of the heat medium-refrigerant heat exchanger 27 in the refrigerant flow path 20g. The refrigerant flow path 20g is a flow path through which the refrigerant branched from the refrigerant flow path 20c passes through the heat medium-refrigerant heat exchanger 27 and then flows to the refrigerant flow path 20d. In the refrigerant circuit 20, when the refrigerant flows into the refrigerant flow passage 20g, the pressure of this refrigerant is reduced by the third expansion valve 23c, and the refrigerant flows into the heat medium-refrigerant heat exchanger 27. The refrigerant flowing into the heat medium-refrigerant heat exchanger 27 evaporates within the heat medium-refrigerant heat exchanger 27 and exchanges heat with the heat medium flowing through the auxiliary heating section 30 .

<Auxiliary heating section>
The auxiliary heating unit 30 circulates a heat medium (for example, water, a refrigerant such as HFO-1234yf, a liquid such as a coolant, or air) through the battery, which is the temperature control target device 100, to adjust the temperature of the temperature control target device 100. It consists of a circuit for

The auxiliary heating section 30 includes a circulation pump 31 as a circulation device that circulates the heat medium, a heat medium heating device (ECH) 32 that heats the heat medium, and switches the flow direction of the heat medium circulating within the auxiliary heating section 30. For example, a directional switching valve 33 such as a three-way valve, and an air flow passage heat exchanger (intra-air flow passage heat exchanger) that is provided between a heat absorber 15 and a heat radiator 16 in the air flow direction in the air conditioning unit 10 and exchanges heat between the heat medium and the air. (heater core) 34.

In the auxiliary heating section 30, a circulation pump 31, a heat medium heating device 32, a heat medium-refrigerant heat exchanger 27, a temperature control target device 100, and an air flow passage heat exchanger 34 are connected in an annular manner by heat medium piping, and the direction The switching valve 33 forms a heat medium circulation circuit 30a in which the flow path of the heat medium can be switched.

In FIG. 1, the heat medium circulation circuit 30a is connected to the discharge side of the circulation pump 31 and the heat medium inflow side of the heat medium heating device 32 through heat medium piping, and to the heat medium outflow side of the heat medium heating device 32. and the heat medium inflow side of the heat medium-refrigerant heat exchanger 27 are connected, and the heat medium outflow side of the heat medium-refrigerant heat exchanger 27 and the heat medium inflow side of the temperature control target device 100 are connected via the directional control valve 33. A "first heat medium circulation circuit 30b" is formed in which the heat medium outflow side of the temperature control target device 100 and the heat medium suction side (inflow side) of the circulation pump 31 are connected. In the first heat medium circulation circuit 30b, when the heat medium is started from the circulation pump 31, the heat medium is sequentially distributed from the circulation pump 31 to the heat medium heating device 32, the heat medium-refrigerant heat exchanger 27, and the direction switching valve. 33"→"temperature control target equipment 100", and returns to the circulation pump 31 again.

In addition, in FIG. 1, the heat medium circulation circuit 30a connects the heat medium outlet side of the heat medium-refrigerant heat exchanger 27 and the heat medium of the air flow path heat exchanger 34 via the heat medium piping through the directional switching valve 33. A "second heat medium circulation circuit 30c" is formed in which the inflow side is connected, and the heat medium outflow side of the air flow passage heat exchanger 34 and the heat medium suction side of the circulation pump 31 are connected. In the second heat medium circulation circuit 30c, the heat medium is distributed from the circulation pump 31 to the heat medium heating device 32, the heat medium-refrigerant heat exchanger 27, and the direction switching valve. 33"→"air flow passage heat exchanger 34"→"circulation pump 31", and returns to the circulation pump 31 again.

<Control device>
The control device 40 includes an ECU (Electronic Control Unit) that includes a well-known microcomputer including a CPU, ROM, RAM, etc., and its peripheral circuits. The control device 40 performs various calculations and processes based on a control program stored in the ROM, and controls the operations of various control objects connected to the output side.

As shown in FIG. 2, the control device 40 includes an outside air temperature sensor 41 for detecting the temperature outside the vehicle interior, an inside air temperature sensor 42 for detecting the temperature inside the vehicle interior, and a temperature sensor 42 for detecting the temperature of the heat absorber 15 (heat absorber 15). A heat absorber temperature sensor 43 for detecting the temperature of the air passing through the heat absorber 15, the temperature of the heat absorber 15 itself, or the temperature of the refrigerant immediately after leaving the heat absorber 15; a radiator temperature sensor 44 for detecting the temperature of the air passing through the radiator 16, the temperature of the radiator 16 itself, or the temperature of the refrigerant immediately after leaving the radiator 16, and an inside air humidity sensor 44 for detecting the humidity inside the vehicle interior. A sensor 45, a blowout temperature sensor 46 for detecting the temperature of the air blown into the vehicle interior from the blowout port, and a refrigerant pressure in the heat absorber 15 (inside the heat absorber 15 or of the refrigerant immediately after leaving the heat absorber 15). a heat sink pressure sensor 47 for detecting the refrigerant pressure (pressure); and a heat sink pressure sensor 48 for detecting the refrigerant pressure in the radiator 16 (pressure of the refrigerant within the radiator 16 or immediately after leaving the radiator 16). , a discharge pressure sensor 49 for detecting the discharge refrigerant pressure of the compressor 21, a compressor temperature sensor 50 for detecting the temperature of the refrigerant sucked into the compressor 21 and the temperature of the refrigerant discharged, and the compressor 21. 21 and the temperature of the outdoor heat exchanger 22 (the temperature of the outdoor heat exchanger 22 itself or the temperature of the refrigerant immediately after coming out of the outdoor heat exchanger 22). and an outdoor heat exchanger temperature sensor 52 for detecting the refrigerant pressure of the outdoor heat exchanger 22 (the pressure of the refrigerant inside the outdoor heat exchanger 22 or immediately after coming out of the outdoor heat exchanger 22). The exchanger pressure sensor 53 and the temperature of the air flow passage heat exchanger 34 (the temperature of the air flow passage heat exchanger 34 itself, the temperature of the heat medium leaving the air flow passage heat exchanger 34, or the air flow passage heat exchanger 34) an air flow passage internal heat exchanger temperature sensor 54 for detecting the temperature of the heat medium entering the internal heat exchanger 34; a photo sensor-type solar radiation sensor 55 for detecting the amount of solar radiation; A speed sensor 56 for detecting the temperature of the temperature controlled device 100 (the temperature of the temperature controlled device 100 itself, the temperature of the heat medium leaving the temperature controlled device 100, or the temperature of the heat medium entering the temperature controlled device 100). A device temperature sensor 57 for detecting temperature (temperature) is connected to a setting operation section 58 for making settings by the passenger regarding setting the temperature in the vehicle interior and switching the operation contents of the air conditioner. Each of the above-mentioned sensors is installed at a position within the vehicle interior (or outside the vehicle interior) where information to be detected can be detected.

Further, as shown in FIG. 2, the control device 40 includes an indoor blower 14, an air mix damper 17, a compressor 21, an outdoor blower 22a, and expansion valves 23 (first expansion valve 23a to third expansion valve 23c), solenoid valves 24 (first solenoid valve 24a, second solenoid valve 24b), heat medium heating device 32, and direction switching valve 33 are connected.

The control device 40 performs drive control of each connected section based on information detected by each sensor and an operation signal from a setting operation section 58. In addition, when the control device 40 inputs an operation mode setting instruction from the setting operation unit 58, the control device 40 selects an "air conditioning mode" in which the air conditioning unit 10 and the refrigerant circuit 20 are driven to manage the air conditioning in the vehicle interior, and an air conditioning mode as the operating mode. The drive control of each part is performed so that the "auxiliary heating mode" is executed by adding an auxiliary heating function to the heating mode set as the mode.

Further, when executing the auxiliary heating mode, when the control device 40 determines that air conditioning operation using the refrigerant circuit 20 is possible, the control device 40 controls the heating medium heating device 32 so that the output is equal to or less than a preset output limit value. Drive with limited output. The output limit value is generally set to 50% or less of the maximum output, although it depends on the equipment performance of the heat medium heating device 32, in order to prevent deterioration of durability caused by driving the heat medium heating device 32 at the maximum output. It's fine.

Further, when executing the auxiliary heating mode, the control device 40 determines that the air conditioning operation using the refrigerant circuit 20 is possible but not or the air conditioning operation using the refrigerant circuit 20 is not possible. The output of the heat medium heating device 32 based on the output limit value is canceled so that it can be driven to the maximum output.

Note that the determination by the control device 40 as to whether air conditioning operation using the refrigerant circuit 20 is possible is comprehensively determined in consideration of the outside temperature, the temperature of the refrigerant sucked into the compressor 21, the discharge pressure of the compressor 21, etc. . The control device 40 is designed to prevent failure of the compressor 21, not only when the compressor 21 itself fails and does not operate, but also when, for example, the refrigerant temperature is too low and the capacity of the compressor 21 is extremely reduced. A determination is made as to whether "air conditioning operation using the refrigerant circuit 20 is not performed (or cannot be performed)".

Next, the "air conditioning mode" which is the operation mode of the vehicle air conditioner 1 according to the present embodiment will be explained.
The air conditioning mode is a mode that performs air conditioning management such as adjusting the temperature/humidity inside the vehicle interior, and there are two modes: "cooling mode" that performs cooling operation that lowers the temperature inside the vehicle interior, and "cooling mode" that reduces the humidity and temperature inside the vehicle interior. "Dehumidifying cooling mode" performs dehumidifying cooling operation that increases the temperature inside the vehicle, "Heating mode" performs heating operation that increases the temperature inside the vehicle interior, and "Dehumidifying heating mode" performs dehumidifying heating operation that increases the temperature while decreasing the humidity inside the vehicle interior. "mode".

<Cooling mode>
In the cooling mode, in the air conditioning unit 10, the indoor blower 14 is driven, and the opening degree of the air mix damper 17 is set so that air does not flow into the radiator 16 side. In the refrigerant circuit 20, the compressor 21 is operated with the first expansion valve 23a fully open, the second expansion valve 23b set to a predetermined valve opening degree, and the first solenoid valve 24a and the second solenoid valve 24b closed. drive.

Thereby, the refrigerant flowing through the refrigerant circuit 20 is discharged from the compressor 21, passes through the radiator 16 and the first expansion valve 23a, and flows into the outdoor heat exchanger 22. The refrigerant that has flowed into the outdoor heat exchanger 22 is air-cooled by the outside air ventilated by the outdoor blower 22a, and is condensed.

When the refrigerant flowing out from the outdoor heat exchanger 22 passes through the first check valve 25a and reaches the second expansion valve 23b, the refrigerant is depressurized, and then flows into the heat absorber 15 and evaporates. Thereafter, the refrigerant flowing out from the heat absorber 15 passes through the second check valve 25b, flows into the accumulator 26, is separated into gas and liquid, and is then sucked into the compressor 21. The refrigerant circulates within the refrigerant circuit 20 following the above-mentioned path.

The air flowing through the air flow path 11 is cooled to a target blowing temperature by exchanging heat with the refrigerant that absorbs heat in the heat absorber 15, and is blown out into the vehicle interior.

<Dehumidification cooling mode>
In the dehumidifying cooling mode, the opening degree of the air conditioning unit 10 is set so that both the bypass passage 11a and the air mix damper 17 are ventilated. In the refrigerant circuit 20, the compressor 21 is operated with the first expansion valve 23a fully open, the second expansion valve 23b set to a predetermined valve opening degree, and the first solenoid valve 24a and the second solenoid valve 24b closed. drive.

As a result, the refrigerant flowing through the refrigerant circuit 20 is discharged from the compressor 21, flows into the radiator 16, exchanges heat with the air in the airflow passage 11, removes heat, is cooled, and condenses. . When the refrigerant flowing out from the radiator 16 reaches the first expansion valve 23a, it is depressurized and then flows into the outdoor heat exchanger 22. The refrigerant that has flowed into the outdoor heat exchanger 22 is cooled by the outside air ventilated by the outdoor blower 22a, and is condensed.

When the refrigerant flowing out from the outdoor heat exchanger 22 passes through the first check valve 25a and reaches the second expansion valve 23b, the refrigerant is depressurized, and then flows into the heat absorber 15 and evaporates. Thereafter, the refrigerant flowing out of the heat absorber 15 passes through the second check valve 25b, flows into the accumulator 26, is separated into gas and liquid, and is then sucked into the compressor 21. The refrigerant circulates within the refrigerant circuit 20 following the above-mentioned path.

The air flowing through the air flow path 11 is cooled and dehumidified by exchanging heat with the refrigerant that absorbs heat in the heat absorber 15, and is reheated by exchanging heat with the refrigerant that radiates heat in the radiator 16, so that the target blowout temperature is reached. The air is blown out into the passenger compartment.

<Heating mode>
In the heating mode, in the air conditioning unit 10, the indoor blower 14 is driven, and the opening degree of the air mix damper 17 is set so that air is ventilated to the radiator 16. In addition, in the refrigerant circuit 20, the first expansion valve 23a is set to a predetermined valve opening smaller than fully open, the second expansion valve 23b and the first solenoid valve 24a are closed, and the second solenoid valve 24b is fully opened. The compressor 21 is driven in this state.

As a result, the refrigerant flowing through the refrigerant circuit 20 is discharged from the compressor 21, flows into the radiator 16, exchanges heat with the air in the airflow passage 11, removes heat, is cooled, and condenses. . When the refrigerant flowing out from the radiator 16 reaches the first expansion valve 23a, it is depressurized and then flows into the outdoor heat exchanger 22. The refrigerant that has flowed into the outdoor heat exchanger 22 evaporates and absorbs heat from the outside air ventilated by the outdoor blower 22a.

The refrigerant flowing out from the outdoor heat exchanger 22 passes through the second electromagnetic valve 24b and the second check valve 25b, flows into the accumulator 26, and is sucked into the compressor 21 after being separated into gas and liquid. The refrigerant circulates within the refrigerant circuit 20 following the above-mentioned path.

The air flowing through the air flow path 11 is heated by exchanging heat with the refrigerant radiating heat within the radiator 16, and is blown into the vehicle interior after being adjusted to a target blowing temperature.

<Dehumidification heating mode>
The dehumidifying heating mode includes a first dehumidifying heating mode and a second dehumidifying heating mode.

(1st dehumidification heating mode)
In the first dehumidifying heating mode, the indoor blower 14 is driven in the air conditioning unit 10, and the opening degree is set so that both the bypass passage 11a and the air mix damper 17 are ventilated. In addition, in the refrigerant circuit 20, the first expansion valve 23a and the second expansion valve 23b are each set to a predetermined valve opening smaller than fully open, and the first solenoid valve 24a and the second solenoid valve 24b are closed. The machine 21 is driven.

As a result, the refrigerant flowing through the refrigerant circuit 20 is discharged from the compressor 21, flows into the radiator 16, exchanges heat with the air in the airflow passage 11, removes heat, is cooled, and condenses. . When the refrigerant flowing out from the radiator 16 reaches the first expansion valve 23a, it is depressurized and then flows into the outdoor heat exchanger 22. The refrigerant that has flowed into the outdoor heat exchanger 22 evaporates and absorbs heat from the outside air ventilated by the outdoor blower 22a.

When the refrigerant flowing out from the outdoor heat exchanger 22 passes through the first check valve 25a and reaches the second expansion valve 23b, the refrigerant is depressurized, and then flows into the heat absorber 15 and evaporates. Thereafter, the refrigerant flowing out from the heat absorber 15 passes through the second check valve 25b, flows into the accumulator 26, is separated into gas and liquid, and is then sucked into the compressor 21. The refrigerant circulates within the refrigerant circuit 20 following the above-mentioned path.

The air flowing through the air flow path 11 is dehumidified and cooled by exchanging heat with the refrigerant that absorbs heat in the heat absorber 15, and is heated by exchanging heat with the refrigerant that radiates heat in the radiator 16, thereby achieving the target blowout. The temperature is adjusted and it is blown into the passenger compartment.

(Second dehumidification heating mode)
In the second dehumidification/heating mode, the indoor blower 14 is driven in the air conditioning unit 10, and the opening degree is set so that both the bypass passage 11a and the air mix damper 17 are ventilated. In the refrigerant circuit 20, the first expansion valve 23a is closed, the second expansion valve 23b is set to a predetermined valve opening degree, the first solenoid valve 24a is opened, and the second solenoid valve 24b is closed. The machine 21 is driven.

As a result, the refrigerant flowing through the refrigerant circuit 20 is discharged from the compressor 21, flows into the radiator 16, exchanges heat with the air in the airflow passage 11, removes heat, is cooled, and condenses. . When the refrigerant flowing out from the radiator 16 passes through the first electromagnetic valve 24a and reaches the second expansion valve 23b, the refrigerant is depressurized, and then flows into the heat absorber 15 and evaporates. Thereafter, the refrigerant flowing out from the heat absorber 15 passes through the second check valve 25b, flows into the accumulator 26, is separated into gas and liquid, and is then sucked into the compressor 21. The refrigerant circulates within the refrigerant circuit 20 following the above-mentioned path.

The air flowing through the air flow passage 11 is cooled by exchanging heat with the refrigerant that absorbs heat in the heat absorber 15, heated by exchanging heat with the refrigerant that radiates heat in the radiator 16, and is adjusted to the target blowout temperature. It is blown out into the passenger compartment.

Next, the "auxiliary heating mode" executed by the vehicle air conditioner 1 according to the present embodiment will be explained with reference to FIGS. 3 to 6. Note that the arrows shown in each figure indicate the flow of the refrigerant or heat medium when the corresponding mode is executed.

The "auxiliary heating mode" is a mode that is switched when the controller 40 determines that the auxiliary heating function is necessary when the "heating mode" is set as the air conditioning mode. In other words, when the user sets the heating mode, the control device 40 determines that if the auxiliary heating function is not necessary, the ``heating mode'' is set, and if the auxiliary heating function is required, the ``auxiliary heating mode'' is set as the heating operation. mode is executed.

"Auxiliary heating mode" allows air conditioning operation using the refrigerant circuit 20, and "Normal auxiliary heating mode" and "Low temperature mode" which are set to use the auxiliary heating function in combination with operation in heating mode as air conditioning operation. "Auxiliary heating mode" means that air conditioning operation using the refrigerant circuit is possible, but the air conditioning operation is not performed, for example, when the outside temperature is extremely low (less than -15 degrees Celsius) or when the compressor 21 itself breaks down. This includes an "emergency auxiliary heating mode" that is set when it is determined that air conditioning operation using the refrigerant circuit 20 is not possible.

Further, the "normal auxiliary heating mode" and the "low temperature auxiliary heating mode" are selected and set based on the determination result that the control device 40 compares the outside temperature with a preset mode selection temperature threshold. The mode selection temperature threshold is set, for example, to "-10 degrees Celsius" at which the capacity of the compressor 21 begins to decline, and the control device 40 sets the "normal auxiliary heating mode" when the outside temperature is higher than -10 degrees Celsius, "Low temperature auxiliary heating mode" can be set when the outside temperature is -10°C or lower.

In addition, in this embodiment, the auxiliary heating mode will be explained as a mode that is set on the premise that the heating mode has been set, but the auxiliary heating mode may be set alone during the dehumidifying heating mode or without setting the heating mode. It is also possible to do so.

<Normal auxiliary heating mode>
The normal auxiliary heating mode is set when the outside temperature is at a temperature such as 0°C to -9°C that requires the auxiliary heating function, and the above-mentioned heating mode controls the air flowing through the air flow passage 11. This is a mode in which the air flowing through the air flow passage 11 is heated and supplementary heated using the heat medium heated by the heat medium heating device 32. The normal auxiliary heating mode includes a "first normal auxiliary heating mode" and a "second normal auxiliary heating mode." In the normal auxiliary heating mode, the heat medium circulates through the second heat medium circulation circuit 30c so as to be distributed to the air flow passage heat exchanger 34 serving as the heater core. In the first normal auxiliary heating mode and the second normal auxiliary heating mode, the output of the heat medium heating device 32 is limited so as to be equal to or less than a preset output limit value.

(1st normal auxiliary heating mode)
FIG. 3 shows the flow of the refrigerant and heat medium in the first normal auxiliary heating mode. Note that the flow of refrigerant in the heating mode executed in the first normal auxiliary heating mode is the same as the flow of refrigerant in the refrigerant circuit 20 in the heating mode described above, so a description thereof will be omitted.

As shown in FIG. 3 , the heat medium in the auxiliary heating section 30 in the first normal auxiliary heating mode flows into the heat medium heating device 32 after being discharged from the circulation pump 31 . The heat medium flowing into the heat medium heating device 32 is heated to a predetermined temperature, and then passes through the heat medium-refrigerant heat exchanger 27 and flows into the airflow passage heat exchanger 34.

The heat medium flowing into the air flow passage heat exchanger 34 exchanges heat with the air flowing within the air flow passage 11. The heat medium flowing out from the air flow passage heat exchanger 34 is then sucked into the circulation pump 31.

In the first normal auxiliary heating mode, the air flowing through the air flow passage 11 is auxiliary heated by the air flow passage heat exchanger 34, and this air is further heated by the radiator 16.

(2nd normal auxiliary heating mode)
FIG. 4 shows the flow of the refrigerant and heat medium in the second normal auxiliary heating mode. As shown in FIG. 4, the refrigerant in the refrigerant circuit 20 in the heating mode during the second normal auxiliary heating mode is discharged from the compressor 21, flows into the radiator 16, and interacts with the air in the airflow passage 11. Through heat exchange, heat is removed, cooled, and condensed. When the refrigerant flowing out from the radiator 16 reaches the first expansion valve 23a, it is depressurized and then flows into the outdoor heat exchanger 22. The refrigerant that has flowed into the outdoor heat exchanger 22 evaporates and absorbs heat from the outside air ventilated by the outdoor blower 22a.

The refrigerant flowing out from the outdoor heat exchanger 22 passes through the second electromagnetic valve 24b and the second check valve 25b, flows into the accumulator 26, and is sucked into the compressor 21 after being separated into gas and liquid. The refrigerant circulates within the refrigerant circuit 20 following the above-mentioned path.

Further, a part of the refrigerant flowing out from the radiator 16 passes through the first electromagnetic valve 24a, bypasses the refrigerant passage 20e, passes through the refrigerant passage 20c, and reaches the third expansion valve 23c. After the refrigerant that has reached the third expansion valve 23c is depressurized, it flows into the heat medium-refrigerant heat exchanger 27 and evaporates, absorbing the heat of the heat medium. Thereafter, the refrigerant flowing out from the heat medium-refrigerant heat exchanger 27 flows into the accumulator 26, where it is separated into gas and liquid, and then sucked into the compressor 21.

When the heat medium in the auxiliary heating section 30 in the second normal auxiliary heating mode is discharged from the circulation pump 31, it flows into the heat medium heating device 32. The heat medium flowing into the heat medium heating device 32 is heated to a predetermined temperature and then flows into the heat medium-refrigerant heat exchanger 27 .

The heat medium flowing into the heat medium-refrigerant heat exchanger 27 exchanges heat with the refrigerant flowing into the heat medium-refrigerant heat exchanger 27, and then flows into the air flow passage heat exchanger 34. The heat medium flowing into the air flow passage heat exchanger 34 exchanges heat with the air flowing within the air flow passage 11. The heat medium flowing out from the air flow passage heat exchanger 34 is then sucked into the circulation pump 31.

In the second normal auxiliary heating mode, as in the first auxiliary heating mode, the air flowing through the airflow passage 11 is auxiliary heated by the airflow passageway heat exchanger 34, and this air flows into the radiator 16. and further heated.

In the second normal auxiliary heating mode, in order to prevent a decrease in the capacity of the compressor 21 due to a decrease in the temperature of the refrigerant, the heat medium heated by the heat medium heating device 32 and the compressor in the heat medium-refrigerant heat exchanger 27 are The temperature of the refrigerant is increased by exchanging heat with the refrigerant before being sucked into the refrigerant 21.

<Low temperature auxiliary heating mode>
The low-temperature auxiliary heating mode is set when the outside temperature is lower than the temperature at which the normal auxiliary heating mode is set, such as around -10°C to -15°C. At the same time, the heat medium-refrigerant heat exchanger 27 heats the heat medium heated by the heat medium heating device 32 and the refrigerant before being sucked into the compressor 21 to heat the air flowing through the refrigerant 11. This mode increases the temperature. In the low-temperature auxiliary heating mode, the heat medium does not flow through the airflow passage heat exchanger 34 serving as the heater core, but circulates through the first heat medium circulation circuit 30b. In the low temperature auxiliary heating mode, similarly to the normal auxiliary heating mode, the output of the heat medium heating device 32 is limited to a preset output limit value or less.

FIG. 5 shows the flow of the refrigerant and the heat medium in the low temperature auxiliary heating mode. Note that the flow of the refrigerant in the refrigerant circuit 20 in the heating mode during the low temperature auxiliary heating mode is the same as the flow of the refrigerant in the second normal auxiliary heating mode, so a description thereof will be omitted.

As shown in FIG. 5 , the heat medium in the auxiliary heating section 30 in the low temperature auxiliary heating mode flows into the heat medium heating device 32 after being discharged from the circulation pump 31 . The heat medium flowing into the heat medium heating device 32 is heated to a predetermined temperature and then flows into the heat medium-refrigerant heat exchanger 27 .

The heat medium flowing into the heat medium-refrigerant heat exchanger 27 exchanges heat with the refrigerant flowing into the heat medium-refrigerant heat exchanger 27, and then flows into the temperature control target device 100. The heat medium that has flowed into the temperature-controlled device 100 is sucked into the circulation pump 31 after adjusting the temperature of the temperature-controlled device 100 .

In the low temperature auxiliary heating mode, the outside temperature is as low as -10°C to -15°C, and heat exchange between the refrigerant and the outside air by the outdoor heat exchanger 22 may be insufficient, but the heat heated by the heat medium heating device 32 By exchanging heat between the medium and the refrigerant in the heat medium-refrigerant heat exchanger 27 to raise the temperature of the refrigerant, it is possible to perform heat exchange with the refrigerant while adjusting the temperature of the temperature control target device 100.

In addition, in the low-temperature auxiliary heating mode, by not allowing the heat medium to flow through the air flow passage heat exchanger 34, the suction pressure of the compressor 21 increases compared to the normal heating mode, and as a result, the output of the compressor 21 decreases. Therefore, the output of the heat medium heating device 32 can be suppressed.

Furthermore, in the low temperature auxiliary heating mode, the temperature of the heat medium is adjusted so that the driving temperature falls within the range of, for example, 10° C. to 40° C. in order to prevent deterioration of the lifespan/performance of the battery serving as the temperature controlled device 100.

<Emergency auxiliary heating mode>
The emergency auxiliary heating mode is used, for example, when the outside temperature is extremely low, below -15°C, and the temperature of the refrigerant is so low that there is a risk that the compressor 21 will break down, or when the compressor 21 itself breaks down. This is an emergency mode that is set when the control device 40 determines that air conditioning operation using the refrigerant circuit 20 is possible but not, or that air conditioning operation using the refrigerant circuit 20 is not possible. In the emergency auxiliary heating mode, the air flowing through the air flow passage 11 is heated only by using the heat medium heated by the heat medium heating device 32 without operating in the heating mode. It circulates through the second heat medium circulation circuit 30c so as to be distributed to the in-path heat exchanger 34.

FIG. 6 shows the flow of the heat medium in the emergency auxiliary heating mode. As shown in FIG. 6 , the heat medium in the auxiliary heating section 30 in the emergency auxiliary heating mode flows into the heat medium heating device 32 after being discharged from the circulation pump 31 . The heat medium flowing into the heat medium heating device 32 is heated to a predetermined temperature, and then passes through the heat medium-refrigerant heat exchanger 27 and flows into the airflow passage heat exchanger 34.

The heat medium flowing into the air flow passage heat exchanger 34 exchanges heat with the air flowing within the air flow passage 11 . The heat medium flowing out from the air flow passage heat exchanger 34 is then sucked into the circulation pump 31.

In the emergency auxiliary heating mode, heating operation in the heating mode is not possible, so the heat exchanger 34 in the airflow passageway exchanges heat between the heat medium and the air in the airflow passageway 11, and the air heated by the heat exchange is used for heating. Use as. Therefore, only in the emergency auxiliary heating mode, the output restriction of the heat medium heating device 32 is canceled and the heating medium heating device 32 can be driven to the maximum output.

As described above, in the vehicle air conditioner 1 according to the present embodiment, three types of modes, which are broadly classified as auxiliary heating modes, are set. The control device 40 determines whether or not the air conditioning operation using the refrigerant circuit 20 is possible, and if it is determined that the air conditioning operation using the refrigerant circuit 20 is possible, the control device 40 selects "normal auxiliary heating mode" or "low temperature mode" depending on the outside temperature. If it is determined that the air conditioning operation using the refrigerant circuit 20 is possible but not or that the air conditioning operation using the refrigerant circuit 20 is not possible, the output of the heat medium heating device 32 is limited. Set the "Emergency Auxiliary Heating Mode" which releases and activates the system.

As a result, when the heating mode is set, the vehicle air conditioner 1 determines whether air conditioning operation using the refrigerant circuit 20 is possible based on the state of the compressor 21 and the outside temperature, and selects an appropriate auxiliary heating mode. can be set, it is possible to maintain a favorable environment in the vehicle interior while suppressing deterioration of the durability of the heat medium heating device 32 as much as possible.

[Processing operation]
Next, with reference to FIG. 7, a processing operation of the vehicle air conditioner 1 according to the present embodiment when the heating mode is executed will be described.
Note that the operations described below are presented with step elements in an exemplary order, and are not limited to the specific order presented. Therefore, the order of the flowchart shown in FIG. 7 can be changed as long as there is no inconsistency in the processing results.

As shown in FIG. 7, when the heating mode is executed as the air conditioning mode (ST1), the control device 40 functions as an auxiliary heating execution determination unit and determines whether it is necessary to switch to the auxiliary heating mode as the operating mode. (ST2).

In ST2, when the control device 40 determines that it is necessary to switch the operation mode to the auxiliary heating mode (ST2-Yes), it then functions as an air conditioning operation execution determination section and starts the air conditioning operation using the refrigerant circuit 20. It is determined whether or not it is possible (that is, whether or not to perform air conditioning operation) (ST3).
On the other hand, in ST2, if the control device 40 determines that there is no need to switch to the auxiliary heating mode as the operating mode (ST2-No), it functions as a drive control section so that the operation in the set heating mode is continued. Each part is driven and controlled (ST4), and the process ends.

In ST3, when the control device 40 determines that air conditioning operation using the refrigerant circuit 20 is possible (ST3-Yes), it then functions as an outside temperature determination section and selects a mode in which the outside temperature is preset. It is determined whether the temperature is below the temperature threshold (ST5).
On the other hand, in ST3, if the control device 40 determines that air conditioning operation using the refrigerant circuit 20 is not possible or not possible (ST3-No), it functions as a drive control section so that processing in the emergency auxiliary heating mode is executed. Then, each part is driven and controlled (ST6), and the process ends.

In ST5, when it is determined that the outside temperature is below the mode selection temperature threshold (ST5-Yes), the control device 40 functions as a drive control section and controls each section so that the process in the low temperature auxiliary heating mode is executed. is driven and controlled (ST7), and the process ends.
On the other hand, in ST5, if the control device 40 determines that the outside temperature exceeds the mode selection temperature threshold (ST5-No), it functions as a drive control section so that processing in the normal auxiliary heating mode is executed. is driven and controlled (ST8), and the process ends.

[Effect]
As described above, the vehicle air conditioner 1 according to the present embodiment includes the air flow path 11 through which air to be supplied into the vehicle interior flows, the compressor 21 that compresses the refrigerant, and the radiator 16 that radiates heat from the refrigerant. , a refrigerant circuit 20 including a heat absorber 15 that absorbs heat from the refrigerant, an outdoor heat exchanger 22 provided outside the vehicle interior that radiates or absorbs heat from the refrigerant, a heat medium heating device 32 that heats the heat medium, and an air flow path. An auxiliary heating section 30 is connected in parallel with the heat absorber 15, and an auxiliary heating section 30, in which the heat medium heated by the heat medium heating device 32 circulates, is connected in parallel with the heat absorber 15, and is connected in parallel with the heat absorber 15, The refrigerant branched and distributed from the first refrigerant flow path (refrigerant flow path 20c) formed between the heat exchanger 22 and the heat absorber 15 is depressurized by the third expansion valve 23c, and the refrigerant is depressurized by the third expansion valve 23c. When it is determined that air conditioning operation using the refrigerant circuit 20 and the heat medium-refrigerant heat exchanger 27 that exchanges heat with the heat medium by absorbing heat from the depressurized refrigerant is possible, and that it is necessary to add an auxiliary heating function. includes a control device 40 that drives the heat medium heating device 32 based on an output limit value set to 50% or less of the maximum output of the heat medium heating device 32.

Therefore, when the heating mode is set, an appropriate auxiliary heating mode can be selected based on the driving state of the compressor 21 and the outside temperature, and the environment inside the vehicle can be maintained in a good condition. In addition, since the output of the heat medium heating device 32 is driven below the output limit value set to an extent that does not deteriorate durability, the environment inside the vehicle is maintained while suppressing deterioration of the durability of the heat medium heating device 32 as much as possible. Can be kept in good condition.

In the vehicle air conditioner 1 according to the present embodiment, the refrigerant circuit 20 is branched from a second refrigerant flow path (refrigerant flow path 20b) formed between the radiator 16 and the outdoor heat exchanger 22. , a third refrigerant flow passage (refrigerant flow passage 20e) bypassing the outdoor heat exchanger 22 and connected to the first refrigerant flow passage; The first heat medium circulation circuit 30b causes the heat medium to flow into the heat medium heating device 32 again via the heat medium-refrigerant heat exchanger 27, and the heat medium heated by the heat medium heating device 32 is passed through the heat medium-refrigerant heat exchanger. The heat medium flowing out from the heat medium-refrigerant heat exchanger 27 flows into the air flow passage heat exchanger 34, and the heat medium flowing out from the air flow passage heat exchanger 34 is heated again. A second heat medium circulation circuit 30c that causes the medium to flow into the medium heating device 32, and the control device 40 controls the heat medium-refrigerant heat exchanger 27 when the outside temperature is below a preset mode selection temperature threshold. Heat is exchanged between the heat medium circulating in the first heat medium circulation circuit 30b and the refrigerant flowing into the heat medium-refrigerant heat exchanger 27 through the third refrigerant flow path.

The heat medium circulates through the first heat medium circulation circuit 30b without flowing through the air flow passage heat exchanger 34, and the refrigerant circulating within the refrigerant circuit 20 is transferred to the first heat medium circulation circuit 30b in the heat medium-refrigerant heat exchanger 27. Since heat is exchanged with the heat medium flowing through the medium circulation circuit 30b, operation in heating mode is possible with the output of the compressor 21 being increased. Therefore, even if the outside temperature drops to -10° C. or lower, for example, the environment inside the vehicle can be maintained in a good condition.

Further, in the vehicle air conditioner 1 according to the present embodiment, the control device 40 determines that the air conditioning operation using the refrigerant circuit 20 is possible, but does not perform the air conditioning operation, or that the air conditioning operation using the refrigerant circuit 20 is not possible. In this case, the output limit set by the output limit value of the heat medium heating device 32 is canceled to heat the heat medium, and the air flowing through the air flow passage 11 is heated by only circulating the heat medium by the second heat medium circulation circuit 30c. Let it heat up.

For example, when the outside temperature is extremely low, such as below -15°C, or when the compressor 21 itself breaks down, air conditioning operation using the refrigerant circuit 20 is possible, but it is possible to not operate the air conditioning operation or to use the refrigerant circuit 20. Only in the case of an emergency when the air conditioning operation cannot be performed, the output restriction of the heat medium heating device 32 is released and the heating function is activated. Can be kept in good condition.

1 Vehicle air conditioner 10 Air conditioning unit 11 Air flow passage (11a bypass flow passage)
12 Inlet (12a outside air inlet, 12b inside air inlet)
13 Suction port switching damper 14 Indoor blower 15 Heat absorber 16 Heat radiator 17 Air mix damper 20 Refrigerant circuit (20a to 20g refrigerant flow path)
21 Compressor 22 Outdoor heat exchanger 23 Expansion valve (23a first expansion valve, 23b second expansion valve, 23c third expansion valve)
24 Solenoid valve (24a first solenoid valve, 24b second solenoid valve)
25 Check valve (25a first check valve, 25b second check valve)
26 Accumulator 27 Heat medium-refrigerant heat exchanger 28 Control valve 30 Auxiliary heating section (30a heat medium circulation circuit, 30b first heat medium circulation circuit, 30c second heat medium circulation circuit)
31 Circulation pump 32 Heat medium heating device 33 Directional switching valve 34 Air flow path heat exchanger 40 Control device

Claims (3)

an air flow path through which air to be supplied to the vehicle interior circulates;
A refrigerant circuit including a compressor that compresses a refrigerant, a radiator that radiates heat from the refrigerant, a heat absorber that absorbs heat from the refrigerant, and an outdoor heat exchanger that is provided outside the vehicle interior and that radiates or absorbs heat from the refrigerant;
The heat medium heating device includes a heat medium heating device that heats a heat medium, and an air flow path heat exchanger that is provided in the air flow path and radiates heat from the heat medium, and the heat medium heated by the heat medium heating device circulates. An auxiliary heating section,
a heat medium-refrigerant heat exchanger that exchanges heat with the heat medium by causing the refrigerant distributed by branching from a first refrigerant flow path formed between the outdoor heat exchanger and the heat absorber to absorb heat; ,
an air conditioning operation execution determination unit that determines whether air conditioning operation using the refrigerant circuit is possible;
an auxiliary heating execution determination unit that determines whether to add an auxiliary heating function;
When the air conditioning operation execution determination unit determines that air conditioning operation using the refrigerant circuit is possible, and the auxiliary heating execution determination unit determines that addition of an auxiliary heating function is necessary, the output of the heat medium heating device is a drive control unit that drives the drive while limiting the output to a predetermined output limit value or less ;
an outside temperature determination unit that determines whether the outside temperature is below a predetermined temperature threshold;
The refrigerant circuit is
A third refrigerant flow path that branches from a second refrigerant flow path formed between the radiator and the outdoor heat exchanger, bypasses the outdoor heat exchanger, and connects to the first refrigerant flow path. Prepare,
The auxiliary heating section is
a first heat medium circulation circuit that causes the heat medium heated by the heat medium heating device to flow into the heat medium heating device again via the heat medium-refrigerant heat exchanger;
The heat medium heated by the heat medium heating device is caused to flow into the heat medium-refrigerant heat exchanger, and the heat medium flowing out from the heat medium-refrigerant heat exchanger is passed through the air flow path heat exchanger. a second heat medium circulation circuit that causes the heat medium flowing out of the air flow passage heat exchanger to flow into the heat medium heating device again;
The drive control section includes:
When the outside temperature determination unit determines that the outside temperature is equal to or lower than the temperature threshold, the first heat medium circulation circuit circulates the heat medium, and the first heat medium is heated in the heat medium-refrigerant heat exchanger. exchanging heat between the heat medium circulating in the medium circulation circuit and the refrigerant flowing into the heat medium-refrigerant heat exchanger through the third refrigerant flow path;
Vehicle air conditioner. The output limit value is set to 50% or less of the maximum output of the heat medium heating device,
The vehicle air conditioner according to claim 1. The drive control section includes:
When the air conditioning operation execution determination unit determines that air conditioning operation using the refrigerant circuit is possible but not air conditioning operation or that air conditioning operation using the refrigerant circuit is not possible;
The output limit based on the output limit value of the heat medium heating device is canceled to heat the heat medium, and the heat medium is circulated in the second heat medium circulation circuit, so that the air flows through the air flow path. to heat the
The vehicle air conditioner according to claim 1 or 2 .

Images