JP2023107644A - Air conditioner for vehicle - Google Patents

Abstract

An object of the present invention is to accurately estimate the air temperature at the outlet of a radiator and to accurately control the temperature of the air blown into the passenger compartment even during heating operation using a hot gas circuit. A compressor 2 for compressing a refrigerant, an indoor heat exchanger (radiator) 4 for heating air supplied to a vehicle interior with the heat of the refrigerant, and an outdoor heat exchanger 7 for exchanging heat between the refrigerant and outside air. and a control device 100 for controlling the refrigerant circuit. The refrigerant circuit bypasses the outdoor heat exchanger and passes through the radiator to flow into the suction side of the compressor. It has a hot gas circuit, and the controller can execute a hot gas heating mode using the hot gas circuit. In the hot gas heating mode, the saturation temperature calculated from the outlet refrigerant pressure of the radiator and the Provided is a vehicle air conditioner that calculates an estimated value of the outlet air temperature of the radiator using a correction value obtained based on the degree of superheat on the inlet side or the degree of superheat on the outlet side. [Selection drawing] Fig. 1

Description

TECHNICAL FIELD The present invention relates to a heat pump type vehicle air conditioner applied to a vehicle, and more particularly to a vehicle air conditioner having a plurality of operation modes.

2. Description of the Related Art In recent years, vehicles such as hybrid vehicles and electric vehicles, in which a driving motor is driven by electric power supplied from a battery mounted in the vehicle, have become widespread. As a vehicle air conditioner mounted on such a vehicle, there are a compressor, a radiator (condenser) provided in the air flow passage to dissipate heat from the refrigerant, and a heat absorber provided in the air flow passage to absorb heat from the refrigerant. (evaporator) and a refrigerant circuit connected to an outdoor heat exchanger that is provided outside the vehicle and that releases or absorbs heat from the refrigerant, and the air in the air flow passage is heat-exchanged with the refrigerant in the radiator or heat absorber. It is known to heat or cool the interior of the vehicle by supplying the air to the interior of the vehicle.

In such a vehicle air conditioner, in addition to cooling or heating the air passing through the air circulation passage in the heat absorber and the radiator, the air mix damper in the air circulation passage controls the volume of the air blown to the radiator. By adjusting, the blowout temperature of the air supplied into the passenger compartment is controlled so as to be the target blowout temperature (for example, Patent Document 1).

The air mix damper is controlled based on the air volume rate SW of the air blown to the radiator. The air volume ratio SW is calculated using an estimated value of the outlet air temperature of the radiator, and this estimated value is calculated using a predetermined estimation formula. In the vehicle air conditioner of Patent Document 1, a different estimation formula is used for each driving mode, and an appropriate estimated value is calculated for each driving mode.

JP 2018-65486 A

By the way, when a vehicle equipped with a vehicle air-conditioning system runs in an environment where the outside air temperature is extremely low (extremely low temperature environment), the refrigerant cannot absorb heat from the outside air in the outdoor heat exchanger. It is conceivable to heat the passenger compartment in a hot gas heating mode using a hot gas circuit in which refrigerant does not pass through the exchanger.

In the hot gas heating mode, since the state change of the refrigerant in the refrigerant circuit is different from that in the normal operation mode, the deviation between the estimated value (estimated temperature) of the outlet air temperature of the radiator and the actual outlet air temperature becomes large. In this case, the air mix damper is controlled based on the air volume ratio SW calculated from the estimated temperature that deviates from the actual outlet air temperature, so that the blowout temperature of the air supplied to the vehicle interior can be accurately controlled. Therefore, comfortable air conditioning cannot be achieved.

The present invention has been made in view of such circumstances, and even during heating operation using a hot gas circuit, the air temperature at the outlet of the radiator can be accurately estimated and the temperature of the air blown into the passenger compartment can be adjusted. The challenge is to perform accurate control and realize comfortable air conditioning.

The present invention provides a refrigerant circuit including a compressor that compresses a refrigerant, a radiator that heats air supplied to a vehicle interior with the heat of the refrigerant, and an outdoor heat exchanger that exchanges heat between the refrigerant and the outside air, and the refrigerant circuit. and the refrigerant circuit has a hot gas circuit in which the refrigerant discharged from the compressor bypasses the outdoor heat exchanger and flows into the suction side of the compressor via the radiator. The control device is capable of executing a hot gas heating mode in which the refrigerant is circulated in the hot gas circuit and the interior of the vehicle is heated by the heat of the refrigerant compressed by the compressor, and in the hot gas heating mode , an estimated value of the outlet air temperature of the radiator using a correction value obtained based on the saturation temperature calculated from the outlet refrigerant pressure of the radiator and the degree of superheat on the inlet side or the degree of superheat on the outlet side of the radiator To provide a vehicle air conditioner that calculates

According to the present invention, even during heating operation using a hot gas circuit, the air temperature at the outlet of the radiator is accurately estimated to accurately control the temperature of the air blown into the passenger compartment, realizing comfortable air conditioning. can do.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows schematic structure of the vehicle air conditioner which concerns on embodiment of this invention, and the flow of a refrigerant|coolant. 1 is a block diagram showing a schematic configuration of a control device for a vehicle air conditioner according to an embodiment of the present invention; FIG. FIG. 4 is an explanatory diagram showing the flow of refrigerant in the refrigerant circuit when each operation mode using the hot gas circuit is executed in the vehicle air conditioner according to the embodiment of the present invention; FIG. 4 is a Mollier diagram showing changes in the state of the refrigerant during execution of the hot gas heating mode and the hot gas mode in the vehicle air conditioner according to the embodiment of the present invention. FIG. 4 is a Mollier diagram showing changes in the state of the refrigerant during execution of the battery heating mode in the vehicle air conditioner according to the embodiment of the present invention. 4 is a saturation temperature curve table showing the relationship between refrigerant pressure and saturation temperature. FIG. 4 is an explanatory diagram showing the flow of refrigerant in the refrigerant circuit when the outside air heat absorption heating mode is executed in the vehicle air conditioner according to the embodiment of the present invention; FIG. 4 is a Mollier diagram showing changes in the state of the refrigerant during execution of the outside air heat absorption heating mode in the vehicle air conditioner according to the embodiment of the present invention. FIG. 4 is an explanatory diagram showing the flow of refrigerant in the refrigerant circuit when the battery cooling mode is executed in the vehicle air conditioner according to the embodiment of the present invention;

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated in detail, referring drawings. In the following description, the same reference numerals denote portions having the same functions, and duplication of description in each drawing will be omitted as appropriate.

FIG. 1 shows a schematic configuration of a vehicle air conditioner 1 according to an embodiment of the present invention. The vehicle air conditioner 1 can be applied to a vehicle such as an electric vehicle (EV) that is not equipped with an engine (internal combustion engine) or a so-called hybrid vehicle that shares an engine and an electric motor for running. Such a vehicle is equipped with a battery 55 (for example, a lithium battery), and supplies electric power charged in the battery 55 from an external power source to a motor unit (not shown) including a driving motor (electric motor). drive and run. The vehicle air conditioner 1 is also powered by the battery 55 and driven.

The vehicle air conditioner 1 includes a refrigerant circuit R for performing heat pump operation, and a heat medium circuit 60 for adjusting the temperature of a battery 55 as a temperature control target. The heat medium circuit 60 is connected to the refrigerant circuit R so as to be capable of exchanging heat via a temperature control target heat exchanger 64, which will be described later. The vehicle air conditioner 1 selectively executes various operation modes including air conditioning operation such as heating operation and cooling operation by heat pump operation using the refrigerant circuit R, thereby air conditioning the vehicle interior and adjusting the temperature of the battery 55. conduct.

In addition to the battery 55, the heat medium circuit 60 can also adjust the temperature of, for example, a motor unit and other devices mounted on the vehicle that generate heat.

The refrigerant circuit R is provided in the air flow passage 3 of the compressor 2 that compresses the refrigerant and the HVAC unit 10 through which the air in the vehicle is ventilated and circulated. It functions as an indoor heat exchanger 4 which is a radiator that heats the air supplied to the vehicle interior, an outdoor expansion valve 6 that decompresses and expands the refrigerant during heating, and a radiator (condenser) that heats the refrigerant during cooling. An outdoor heat exchanger 7 for exchanging heat between the refrigerant and the outside air to function as an evaporator that absorbs heat from the refrigerant during heating, an indoor expansion valve 8 for decompressing and expanding the refrigerant, and an air flow passage 3 A heat absorber 9 provided for cooling the air supplied to the vehicle interior by allowing the refrigerant to absorb heat from outside and outside the vehicle interior during cooling and dehumidification, and an accumulator 12 and the like are connected by refrigerant pipes 13A to 13K. .

Both the outdoor expansion valve 6 and the indoor expansion valve 8 are electronic expansion valves driven by a pulse motor (not shown), and the degree of opening is appropriately controlled between fully closed and fully opened depending on the number of pulses applied to the pulse motor. The outdoor expansion valve 6 decompresses and expands the refrigerant flowing out of the indoor heat exchanger 4 and flowing into the outdoor heat exchanger 7 during heating operation or defrosting operation using the outdoor heat exchanger 7. The refrigerant flowing into the heat absorber 9 is decompressed and expanded, and the amount of heat absorbed by the refrigerant in the heat absorber 9, that is, the cooling capacity of the passing air is adjusted.

A refrigerant outlet of the outdoor heat exchanger 7 and a refrigerant inlet of the heat absorber 9 are connected by a refrigerant pipe 13A. A check valve 18 and an indoor expansion valve 8 are provided in order from the outdoor heat exchanger 7 side in the refrigerant pipe 13A. The check valve 18 is provided in the refrigerant pipe 13A so that the direction toward the heat absorber 9 is the forward direction. The refrigerant pipe 13A branches off to the refrigerant pipe 13B at a position closer to the outdoor heat exchanger 7 than the check valve 18 and branches to the refrigerant pipe 13I between the check valve 18 and the indoor expansion valve 8 .

A refrigerant pipe 13B branched from the refrigerant pipe 13A is connected to a refrigerant inlet of the accumulator 12 . The refrigerant pipe 13B is provided with an electromagnetic valve 21 and a check valve 20 that are opened during heating in order from the outdoor heat exchanger 7 side. The check valve 20 is connected so that the direction toward the accumulator 12 is the forward direction. A refrigerant pipe 13C is branched between the solenoid valve 21 and the check valve 20 of the refrigerant pipe 13B. A refrigerant pipe 13C branched from the refrigerant pipe 13B is connected to a refrigerant outlet of the heat absorber 9 . A refrigerant outlet of the accumulator 12 and the compressor 2 are connected by a refrigerant pipe 13D.

A refrigerant outlet of the compressor 2 and a refrigerant inlet of the indoor heat exchanger 4 are connected by a refrigerant pipe 13E. One end of the refrigerant pipe 13F is connected to the refrigerant outlet of the indoor heat exchanger 4, and the other end of the refrigerant pipe 13F is branched into the refrigerant pipe 13G and the refrigerant pipe 13H before the outdoor expansion valve 6 (refrigerant upstream). there is One branched refrigerant pipe 13G is connected to the refrigerant inlet side of the outdoor heat exchanger 7 via the outdoor expansion valve 6 . The other branched refrigerant pipe 13H is connected between the check valve 18 and the indoor expansion valve 8 of the refrigerant pipe 13A. A solenoid valve 22 is provided on the refrigerant upstream side of the connection point between the refrigerant pipe 13H and the refrigerant pipe 13A. The solenoid valve 22 may be an electronic expansion valve.

A refrigerant pipe 13I branched from the refrigerant pipe 13A is connected to a refrigerant flow path 64A of the temperature control target heat exchanger 64, and a chiller expansion valve 72 is provided in the refrigerant pipe 13I. The chiller expansion valve 72 is an electronic expansion valve driven by a pulse motor (not shown), and its opening is appropriately controlled between fully closed and fully opened depending on the number of pulses applied to the pulse motor. The chiller expansion valve 72 decompresses and expands the refrigerant flowing into the refrigerant flow path 64A of the heat exchanger 64 for temperature control. One end of the refrigerant pipe 13J is connected to the outlet of the refrigerant flow path 64A of the heat exchanger 64 for temperature control. The other end of the refrigerant pipe 13J is connected to the vicinity of the inlet of the accumulator 12 of the refrigerant pipe 13B.

As a result, the refrigerant pipe 13H is connected in parallel to the series circuit of the outdoor expansion valve 6, the outdoor heat exchanger 7, and the check valve 18, and bypasses the outdoor expansion valve 6, the outdoor heat exchanger 7, and the check valve 18. do. Then, the refrigerant discharged from the compressor 2 flows to the indoor heat exchanger 4 through the refrigerant pipe 13H and the refrigerant pipe 13I, bypasses the outdoor heat exchanger 7, and passes through the temperature control target heat exchanger 64 to the compressor. A hot gas circuit that flows into the intake side of No. 2 is constructed. Whether or not to allow the refrigerant to flow into the refrigerant pipe 13G, that is, whether or not to use the hot gas circuit can be selected according to the opening/closing of the electromagnetic valve 22 provided in the refrigerant pipe 13H.

A refrigerant outlet of the compressor 2 and a refrigerant suction side of the accumulator 12 are connected by a refrigerant pipe 13K. An electronic expansion valve 24 is provided in the refrigerant pipe 13K, and by opening the electronic expansion valve 24, a bypass circuit can be formed in which the refrigerant discharged from the compressor 2 is sucked into the compressor 2 again.

The air flow passage 3 on the air upstream side of the heat absorber 9 is formed with an external air suction port and an internal air suction port (indicated by a suction port 25 in FIG. 1). A suction switching damper 26 is provided at the suction port 25 . The intake switching damper 26 appropriately switches between the inside air, which is the air inside the vehicle compartment, and the outside air, which is the air outside the vehicle compartment, and introduces the air from the intake port 25 into the air flow passage 3 . An indoor air blower 27 for supplying the introduced inside air and outside air to the air flow passage 3 is provided on the air downstream side of the suction switching damper 26 .

In the air flow passage 3 on the air upstream side of the indoor heat exchanger 4, the air (inside air or outside air) in the air flow passage 3 after flowing into the air flow passage 3 and passing through the heat absorber 9 is converted into indoor heat. An air mix damper 28 is provided for adjusting the ratio of ventilation to the exchanger 4 and the auxiliary heater 23 .

As the auxiliary heating means, for example, hot water heated by compressor waste heat may be circulated through a heater core disposed in the air flow passage 3 to heat the blown air.

The heat medium circuit 60 includes a pump 61 for circulating the heat medium in the heat medium circuit 60 to flow the heat medium to the battery 55, and a temperature control target heat exchanger 64. to adjust the temperature of the battery 55 .

The heat medium circuit 60 is provided so that the refrigerant circulating in the refrigerant circuit R and the heat medium exchange heat in the temperature control target heat exchanger 64 . That is, in the heat medium circuit 60, the heat medium passes through the heat medium flow path 64B of the heat exchanger 64 for temperature adjustment and exchanges heat with the refrigerant passing through the heat medium flow path 64A of the heat exchanger 64 for temperature adjustment. The heat medium whose temperature is adjusted by exchanging heat with the refrigerant passes through the battery 55 by circulating through the heat medium circuit 60 by the pump 61 , thereby adjusting the temperature of the battery 55 .
In this way, the temperature control target heat exchanger 64 constitutes part of the refrigerant circuit R and also constitutes part of the heat medium circuit 60 .

As the heat medium used in the heat medium circuit 60, for example, water, a refrigerant such as HFO-1234yf, a liquid such as a coolant liquid obtained by adding an antifreeze liquid to water, or a gas such as air can be used. In addition, in this embodiment, a coolant liquid is adopted as a heat medium. In addition, the battery 55 is surrounded by, for example, a jacket structure that allows a heat medium to flow in a heat exchange relationship with the battery 55 .

FIG. 2 shows a schematic configuration of a control device 100 that controls the vehicle air conditioner 1 . When the vehicle air conditioner 1 is mounted on a vehicle, the control device 100 is connected to a vehicle controller 35, a CAN (Controller Area Network), and a controller area network (CAN), which controls the entire vehicle including drive control of the motor unit and charge/discharge control of the battery 55. They are connected so as to be able to communicate with each other through an in-vehicle network such as LIN (Local Interconnect Network), and transmit and receive information.

The control device 100 and the vehicle controller 35 include, for example, processors such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit), electric circuits, and storage elements such as RAM (Random Access Memory) and ROM (Read Only Memory). can be applied to a computer equipped with

The following sensors and detectors are connected to the control device 100, and the outputs of these sensors and detectors are input. In the following description, illustrations and descriptions of components that are not directly related to the operation of the vehicle air conditioner 1 according to the present embodiment are omitted.

Specifically, the control device 100 includes an outside air temperature sensor 33 that detects the outside air temperature Tam of the vehicle, an HVAC intake temperature sensor 36 that detects the temperature of the air sucked into the air flow passage 3 from the air intake 25, An inside air temperature sensor 37 that detects the indoor air temperature (inside air temperature Tin), an air outlet temperature sensor 41 that detects the temperature of the air blown into the passenger compartment from the air outlet 29, and an inlet refrigerant temperature Tcxin of the indoor heat exchanger 4. , a suction temperature/pressure sensor 46 that detects the refrigerant suction temperature TS and the suction refrigerant pressure PS of the compressor 2, and an outlet refrigerant temperature Tci of the indoor heat exchanger 4 that detects An indoor heat exchanger temperature sensor 44, an indoor heat exchanger pressure sensor 47 for detecting the outlet refrigerant pressure Pci of the indoor heat exchanger 4, and an air conditioning operation unit 53 for setting a set temperature and switching of air conditioning operation. It is connected.

In addition to the above, the control device 100 includes a battery temperature sensor 76 for detecting the temperature of the battery 55, a heat medium temperature Tw (chiller water temperature ) is connected. To grasp the temperature of the battery 55, either the battery temperature sensor 76 or the heat medium temperature sensor 79 can be used as appropriate.

On the other hand, outputs of the control device 100 include the compressor 2, the indoor fan 27, the suction switching damper 26, the air mix damper 28, the outdoor expansion valve 6, the indoor expansion valve 8, the electromagnetic valves 21 and 22, the electronic expansion valve 24, the pump 61 and chiller expansion valve 72 are connected. The control device 100 controls these based on the output of each sensor, the setting input by the air conditioning operation section 53 and the information from the vehicle controller 35 .

The vehicle air conditioner 1 configured in this manner selects and executes an optimum operation mode from a plurality of operation modes according to the environment in which the vehicle equipped with the vehicle air conditioner 1 runs and the state of the vehicle. be able to. For example, when the vehicle runs in an extremely low temperature environment below a predetermined temperature, the outdoor heat exchanger 7 cannot absorb heat from the outside air. Run gas heating mode.

In addition, since it is necessary to heat the battery 55 in an extremely low temperature environment, a battery heating mode using a hot gas circuit or a hot gas mode in which heating and battery heating are performed at the same time is executed. In addition, the outside air heat absorption heating mode that heats the vehicle interior when heat can be absorbed from the outside air in the outdoor heat exchanger 7, the battery cooling mode that cools the battery 55, and the air cooled in the heat absorber 9 It is possible to execute various operation modes such as a cooling mode that performs cooling.

Hereinafter, in this embodiment, each operation mode using the hot gas circuit (that is, in this embodiment, the three operation modes of the heating mode, the battery heating mode, and the hot gas mode) are executed. The operation of device 1 will be described.

FIG. 3 shows the flow of the refrigerant in the refrigerant circuit R during execution of each operation mode using the hot gas circuit. In FIG. 3, the thick lines indicate the refrigerant pipes through which the refrigerant flows. The hot gas heating mode using the hot gas circuit, the battery heating mode, and the hot gas mode are the rotation speed of the compressor 2, the amount of refrigerant circulating in the refrigerant circuit R, the amount of heat medium circulating in the heat medium circuit 60, and Although there are cases where the flow rate of airflow passing through the HVAC unit 10 is different, the flow path through which the refrigerant circulates or passes through the refrigerant circuit R is the same.

When the heating operation is selected by the control device 100 (auto mode) or by manual operation (manual mode) of the air conditioning operation unit 53 and the vehicle is traveling in an extremely low temperature environment, the control device 100 releases hot gas. Start the heating operation using the circuit. The controller 100 closes the outdoor expansion valve 6 , the indoor expansion valve 8 and the solenoid valve 21 , opens the solenoid valve 22 and chiller expansion valve 72 , and opens the electronic expansion valve 24 . Thereby, a hot gas circuit and a bypass circuit are configured, and the refrigerant can be circulated.

When the operation of the compressor 2 is started in this state, part of the refrigerant discharged from the compressor 2 circulates through the hot gas circuit and the rest circulates through the bypass circuit. That is, part of the refrigerant discharged from the compressor 2 passes through the indoor heat exchanger 4, passes through the solenoid valve 22 and the chiller expansion valve 72, passes through the temperature control target heat exchanger 64, and passes through the accumulator 12. Return to compressor 2. On the other hand, the rest of the refrigerant discharged from the compressor 2 returns to the compressor 2 via the electronic expansion valve 24 and the accumulator 12 .
The differences between the operation modes and the state of the refrigerant circulating in the refrigerant circuit R in each operation mode will be described below.

(1) Hot gas heating mode In the hot gas heating mode, the control device 100 operates the indoor fan 27, and the air mix damper 28 controls the ratio of the air blown from the indoor fan 27 to the indoor heat exchanger 4. to be adjusted. Also, the pump 61 is not operated and the heat medium is not circulated in the heat medium circuit 60 . That is, the refrigerant does not exchange heat with the heat medium when passing through the temperature control target heat exchanger 64 .

FIG. 4 shows a Mollier diagram showing changes in the state of the refrigerant in the hot gas heating mode.
The high-temperature and high-pressure gas refrigerant discharged from the compressor 2 and flowed into the indoor heat exchanger 4 exchanges heat with the air in the air flow passage 3, whereby the air in the air flow passage 3 is heated by the refrigerant. The cooled air is blown out from the outlet 29 into the passenger compartment to heat the vehicle. The refrigerant heat-exchanged in the indoor heat exchanger 4 loses heat to the air, is cooled, and condenses.

After leaving the indoor heat exchanger 4, the condensed refrigerant passes through the refrigerant pipes 13F, 13H, 13A, and 13I, the chiller expansion valve 72, and the heat exchanger 64 to be temperature controlled. The refrigerant expands in the chiller expansion valve 72 to a low temperature and low pressure, passes through the temperature control target heat exchanger 64 without exchanging heat with the heat medium, and flows into the accumulator 12 via the refrigerant pipes 13J and 13B.

On the other hand, the high-temperature, high-pressure gas refrigerant discharged from the compressor 2 passes through the refrigerant pipe 13K, is expanded by the electronic expansion valve 24, and flows into the accumulator 12 again. That is, the refrigerant liquefied by the indoor heat exchanger 4 and the refrigerant expanded by the electronic expansion valve 24 after being compressed by the compressor 2 flow into the accumulator 12 . The refrigerant that has flowed into the accumulator 12 repeats the circulation of being sucked into the compressor 2 through the refrigerant pipe 13D as gas refrigerant after gas-liquid separation.
(2) Battery Heating Mode In the battery heating mode, the control device 100 does not operate the indoor fan 27 and puts the indoor heat exchanger 4 into a state in which heat exchange between refrigerant and air is not performed. That is, the refrigerant only passes through the indoor heat exchanger 4 . Further, the pump 61 is operated to circulate the heat medium in the heat medium circuit 60 so that the heat exchange between the refrigerant and the heat medium is performed in the temperature control target heat exchanger 64 .

FIG. 5 shows a Mollier diagram showing the state change of the refrigerant in the battery heating mode.
The high-temperature and high-pressure gas refrigerant discharged from the compressor 2 and flowed into the indoor heat exchanger 4 passes through the air in the air flow passage 3 without exchanging heat, and the refrigerant leaves the indoor heat exchanger 4, It passes through the refrigerant pipes 13F, 13H, 13A, and 13I in the state of high-temperature and high-pressure gas refrigerant, and then passes through the chiller expansion valve 72 and the heat exchanger 64 for temperature control. The refrigerant exchanges heat with the heat medium in the temperature control target heat exchanger 64 , whereby the heat medium circulating in the heat medium circuit 60 is heated by the refrigerant, and the battery 55 is heated by the heated heat medium. The refrigerant heat-exchanged in the temperature control target heat exchanger 64 loses heat to the heat medium, is cooled and condensed, and flows into the accumulator 12 through the refrigerant pipes 13J and 13B.

On the other hand, the high-temperature, high-pressure gas refrigerant discharged from the compressor 2 passes through the refrigerant pipe 13K, is expanded by the electronic expansion valve 24, and flows into the accumulator 12 again. That is, the refrigerant liquefied by the temperature control target heat exchanger 64 and the refrigerant expanded by the electronic expansion valve 24 after being compressed by the compressor 2 flow into the accumulator 12 . The refrigerant that has flowed into the accumulator 12 repeats the circulation of being sucked into the compressor 2 through the refrigerant pipe 13D as gas refrigerant after gas-liquid separation.

(3) Hot gas mode (operation mode in which hot gas heating and battery heating are performed simultaneously)
In the hot gas mode, the control device 100 operates the indoor blower 27 and puts the air mix damper 28 in a state of adjusting the ratio of the air blown from the indoor blower 27 to the indoor heat exchanger 4 . In addition, the pump 61 is operated to circulate the heat medium in the heat medium circuit 60 , and heat exchange between the refrigerant and the heat medium is performed in the heat exchanger 64 for temperature control.

The Mollier diagram showing the state change of the refrigerant in the hot gas mode is similar to the Mollier diagram showing the state change of the refrigerant in the hot gas heating mode of FIG. 4, so the illustration is omitted.
The high-temperature and high-pressure gas refrigerant discharged from the compressor 2 and flowed into the indoor heat exchanger 4 exchanges heat with the air in the air flow passage 3, whereby the air in the air flow passage 3 is heated by the refrigerant. The cooled air is blown out from the outlet 29 into the passenger compartment to heat the vehicle. The refrigerant heat-exchanged in the indoor heat exchanger 4 loses heat to the air, is cooled, and condenses.

After leaving the indoor heat exchanger 4, the condensed refrigerant passes through the refrigerant pipes 13F, 13H, 13A, and 13I, the chiller expansion valve 72, and the heat exchanger 64 to be temperature controlled. The refrigerant exchanges heat with the heat medium in the temperature control target heat exchanger 64 , whereby the heat medium circulating in the heat medium circuit 60 is heated by the refrigerant, and the battery 55 is heated by the heated heat medium. The refrigerant heat-exchanged in the temperature control target heat exchanger 64 loses heat to the heat medium, is cooled and condensed, and flows into the accumulator 12 through the refrigerant pipes 13J and 13B.

On the other hand, the high-temperature, high-pressure gas refrigerant discharged from the compressor 2 passes through the refrigerant pipe 13K, is expanded by the electronic expansion valve 24, and flows into the accumulator 12 again. That is, into the accumulator 12, the refrigerant liquefied by the indoor heat exchanger 4 and the temperature control target heat exchanger 64 and the refrigerant expanded by the electronic expansion valve 24 after being compressed by the compressor 2 flow into the accumulator 12. . The refrigerant that has flowed into the accumulator 12 repeats the circulation of being sucked into the compressor 2 through the refrigerant pipe 13D as gas refrigerant after gas-liquid separation.

In each operation mode using the hot gas circuit described above, an example in which a bypass circuit is also used has been described, but it is not always necessary to use the bypass circuit, and each operation mode can be executed using only the hot gas circuit. can be When the bypass circuit is used, the high-temperature and high-pressure refrigerant that has been compressed by the compressor 2 is returned to the compressor 2 via the bypass circuit, so power in the compressor 2 can be added. Therefore, the air of the desired temperature can be supplied into the vehicle interior more quickly than when the bypass circuit is not used, and the heat medium in the heat medium circuit 60 can be heated to the desired temperature more quickly. It has the advantage of being able to

(Regarding temperature control of the air blown into the passenger compartment)
When executing the hot gas heating mode and the hot gas mode described above, the control device 100 adjusts the air volume of the air that is ventilated to the indoor heat exchanger 4 by the air mix damper 28, and controls the compressor 2 to heat the room. Control the heating in the exchanger 4; As a result, the control device 100 controls the air blown into the passenger compartment from the air outlet 29 to reach the target air temperature TAO.

Here, the control device 100 controls opening and closing of the air mix damper 28 based on the air volume ratio SW.

The air volume ratio SW is calculated by the following formula (1).
SW=(TAO−Te)/(Heat−Te) (1)
Here, TAO is the target blowout temperature of the air blown into the vehicle interior from the blowout port 29, Te is the outlet air temperature of the heat absorber 9, and Theat is the estimated value of the outlet air temperature of the indoor heat exchanger 4 (hereinafter referred to as "estimated heating temperature”).

The estimated heating temperature Theat can be calculated by the following formula (2).
Theat = (INTL_TH * Theat0 + Tau_TH * Theatz) / (Tau_TH + INTL_TH) (2)
Here, INTL_TH is a calculation period (constant), Tau_TH is a first-order lag time constant, Theat0 is the estimated heating temperature Theat before the first-order lag calculation, and Theatz is the previous value of the estimated heating temperature Theat.

When calculating the estimated heating temperature Theat, by changing the time constant Tau_TH and the steady-state value Theat0 according to the operation mode, the above-mentioned formula (2) is changed to a different formula depending on the operation mode, and the estimated heating temperature Theat is calculated and estimated.

In particular, in the hot gas heating mode and the hot gas mode in which the heating operation is performed using the hot gas circuit, the refrigerant is superheated as shown in the Mollier diagram shown in FIG. Therefore, in the hot gas heating mode and the hot gas mode, the control device 100 controls the saturation temperature calculated from the outlet refrigerant pressure Pci of the indoor heat exchanger 4, the inlet-side superheat degree of the indoor heat exchanger 4, or the outlet-side superheat degree The estimated heating temperature Theat is calculated using the correction value obtained based on.

Specifically, the steady-state value Theat0 in the formula (1) is changed as shown in the following formula (3), and the changed steady-state value Theat0 is used as a correction value in the formula (1) to calculate the estimated heating temperature Theat. do.
Heat0=THsatu+TH_HOS+TH_OFFSET (3)
Here, THsatu is the saturation temperature calculated from the outlet refrigerant pressure Pci of the indoor heat exchanger 4, and can be calculated with reference to a saturation temperature curve table. FIG. 6 shows a saturation temperature curve table showing the relationship between refrigerant pressure and saturation temperature.

TH_HOS is a value obtained based on the inlet-side superheat SHcxin or the outlet-side superheat SHcxout of the indoor heat exchanger 4, and TH_OFFSET is an offset value. TH_HOS can be the sum of the inlet-side superheat SHcxin and the outlet-side superheat SHcxout of the indoor heat exchanger 4, or the inlet-side superheat SHcxin.

The inlet-side superheat SHcxin is obtained by subtracting the saturation temperature THsatu from the inlet refrigerant temperature Tcxin of the indoor heat exchanger 4 . The outlet side superheat SHcxout is obtained by subtracting the saturation temperature THsatu from the outlet refrigerant temperature Tci of the indoor heat exchanger 4 .

In addition, instead of the correction value obtained based on the saturation temperature calculated from the outlet refrigerant pressure Pci of the indoor heat exchanger 4 and the degree of superheat on the inlet side or the degree of superheat on the outlet side of the indoor heat exchanger 4, the control device 100 Alternatively, the estimated value of the outlet air temperature of the indoor heat exchanger 4 may be calculated using a correction value obtained based on the inlet refrigerant temperature of the indoor heat exchanger 4 . That is, by changing the steady-state value Theat0 in the above-described formula (1) to the sum of the inlet refrigerant temperature Tcxin of the indoor heat exchanger 4 and the offset value, and using the changed steady-state value Theat0 as a correction value in formula (1). , the estimated heating temperature Theat can also be calculated.

As described above, according to the vehicle air conditioner 1 according to the present embodiment, when the control device 100 calculates the estimated heating temperature Theat, which is the estimated value of the outlet air temperature, the correction value based on the degree of superheat of the refrigerant take advantage of As a result, the deviation from the actual outlet air temperature of the indoor heat exchanger 4 caused by the change in the state of the refrigerant during heating using the hot gas circuit is suppressed, and the outlet air temperature of the indoor heat exchanger 4 is accurately controlled. can be estimated. Therefore, since the air volume ratio SW can be calculated using the estimated heating temperature Theat with high estimation accuracy, the temperature of the air blown into the vehicle interior can be accurately controlled, and comfortable air conditioning can be realized.
therefore,

As reference examples of other operation modes executable in the vehicle air conditioner 1 according to the present embodiment shown in FIG. 1, the outside air heat absorption heating mode and the battery cooling mode will be described below.
(External air heat absorption heating mode)
FIG. 7 shows the refrigerant flow (thick line) in the refrigerant circuit R in the outside air heat absorption heating mode. Moreover, FIG. 8 is a Mollier diagram showing changes in the state of the refrigerant in the outside air heat absorption heating mode.
When the controller 100 executes the outdoor air heat absorption heating mode, the outdoor expansion valve 6 and the solenoid valve 21 are opened, and the solenoid valve 22, the indoor expansion valve 8, the electronic expansion valve 24, and the chiller expansion valve 72 are fully closed. The compressor 2 and the indoor fan 27 are operated, and the air mix damper 28 adjusts the ratio of the air blown from the indoor fan 27 to the indoor heat exchanger 4 .

As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the indoor heat exchanger 4 . In the indoor heat exchanger 4, heat is exchanged between the air in the air passage 3 and the high-temperature, high-pressure refrigerant. Heating is performed by blowing out to.

On the other hand, the refrigerant passing through the indoor heat exchanger 4 is cooled by being deprived of heat by the air passing through the air flow passage 3, and is condensed and liquefied. After leaving the indoor heat exchanger 4, the liquefied refrigerant reaches the outdoor expansion valve 6 via the refrigerant pipes 13F and 13G. After being decompressed by the outdoor expansion valve 6 , the refrigerant flows into the outdoor heat exchanger 7 . The refrigerant that has flowed into the outdoor heat exchanger 7 evaporates, and draws up heat from the outside air that flows in as the vehicle runs or the outside air that is blown by an outdoor fan (not shown) (heat absorption). That is, the refrigerant circuit R becomes a heat pump.

The low-temperature refrigerant leaving the outdoor heat exchanger 7 flows through the refrigerant pipes 13A and 13B, the solenoid valve 21, and the check valve 20 into the accumulator 12, and after gas-liquid separation in the accumulator 12, the gas refrigerant is The circulation of refrigerant sucked into the compressor 2 through the refrigerant pipe 13D is repeated.

(battery cooling mode)
FIG. 9 shows the refrigerant flow in the refrigerant circuit R in the battery cooling mode. In FIG. 9, refrigerant pipes through which the refrigerant flows are indicated by thick lines. A Mollier diagram showing the state change of the refrigerant in the battery cooling mode is the same as the Mollier diagram showing the state change of the refrigerant in the outside air heat absorption heating mode shown in FIG.
When the controller 100 executes the battery cooling mode, the outdoor expansion valve 6 and the chiller expansion valve 72 are opened, and the solenoid valves 21, 22, the indoor expansion valve 8, and the electronic expansion valve 24 are fully closed. Then, the compressor 2 is operated without operating the indoor air blower 27 .

As a result, although the high-temperature and high-pressure refrigerant discharged from the compressor 2 flows into the indoor heat exchanger 4, it only passes through. It reaches the valve 6. After being decompressed by the outdoor expansion valve 6 , the refrigerant flows into the outdoor heat exchanger 7 . The refrigerant that has flowed into the outdoor heat exchanger 7 is air-cooled by outside air that flows in as the vehicle travels or is blown by an outdoor fan (not shown), and is condensed and liquefied.

The refrigerant exiting the outdoor heat exchanger 7 flows through the refrigerant pipe 13A, the check valve 18, and the chiller expansion valve 72 into the temperature control target heat exchanger 64 and evaporates. The heat absorbing action at this time cools the heat medium circulating in the heat medium circuit 60 .

The refrigerant evaporated in the temperature control target heat exchanger 64 reaches the accumulator 12 through the refrigerant pipe 13J, and is sucked into the compressor 2 through the refrigerant pipe 13D, repeating circulation. The heat medium cooled by the temperature control target heat exchanger 64 is pumped to the battery 55 by the pump 61 to cool the battery 55 .

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and design modifications and the like are possible without departing from the gist of the present invention. Even if there is, it is included in the present invention.

1: vehicle air conditioner, 2: compressor, 3: air flow passage, 4: indoor heat exchanger, 6: outdoor expansion valve, 7: outdoor heat exchanger, 8: indoor expansion valve, 9: heat absorber, 10 : HVAC unit, 12: accumulator, 13A-13K: refrigerant piping, 18, 20: check valve, 21, 22: solenoid valve, 24: electronic expansion valve, 25: suction port, 26: suction switching damper, 27: indoor Blower, 28: Air mix damper, 29: Blowout port, 55: Battery, 60: Heat medium circuit, 61: Pump, 64: Temperature control target heat exchanger, 64A: Refrigerant flow path, 64B: Heat medium flow path, 72 : Chiller expansion valve 100: Control device

Claims (8)

a refrigerant circuit including a compressor that compresses the refrigerant, a radiator that heats the air supplied to the vehicle interior with the heat of the refrigerant, and an outdoor heat exchanger that exchanges heat between the refrigerant and the outside air;
A control device that controls the refrigerant circuit,
The refrigerant circuit has a hot gas circuit in which the refrigerant discharged from the compressor bypasses the outdoor heat exchanger and flows into the suction side of the compressor via the radiator,
The control device is
A hot gas heating mode can be executed in which a refrigerant is circulated in the hot gas circuit and the interior of the vehicle is heated by the heat of the refrigerant compressed by the compressor,
In the hot gas heating mode, the saturation temperature calculated from the outlet refrigerant pressure of the radiator and the correction value obtained based on the inlet-side superheat degree or the outlet-side superheat degree of the radiator A vehicle air conditioner that calculates an estimate of outlet air temperature. 2. The vehicle air conditioner according to claim 1, wherein said control device uses said estimated value to calculate a rate of air flow to said radiator. 3. The vehicle air conditioner according to claim 1, wherein said correction value is the sum of said saturation temperature, said inlet side superheat degree, and an offset value. 3. The vehicle air conditioner according to claim 1, wherein said correction value is the sum of said saturation temperature, said inlet side superheat degree, said outlet side superheat degree, and an offset value. The vehicle air conditioner according to any one of claims 1 to 4, wherein the inlet-side superheat degree is a difference between an inlet refrigerant temperature of the radiator and the saturation temperature. The vehicle air conditioner according to any one of claims 1 to 5, wherein the degree of superheat on the outlet side is a difference between an outlet refrigerant temperature of the radiator and the saturation temperature. a refrigerant circuit including a compressor that compresses the refrigerant, a radiator that heats the air supplied to the vehicle interior with the heat of the refrigerant, and an outdoor heat exchanger that exchanges heat between the refrigerant and the outside air;
A control device that controls the refrigerant circuit,
The refrigerant circuit has a hot gas circuit in which the refrigerant discharged from the compressor bypasses the outdoor heat exchanger and flows into the suction side of the compressor via the radiator,
The control device is
It is possible to execute a hot gas heating mode in which a refrigerant is circulated in the hot gas circuit and the interior of the vehicle is heated by the heat of the refrigerant compressed by the compressor,
An air conditioner for a vehicle, wherein, in the hot gas heating mode, an estimated value of the outlet air temperature of the radiator is calculated using a correction value obtained based on the inlet refrigerant temperature of the radiator. 8. The hot gas circuit according to any one of claims 1 to 7, wherein the hot gas circuit has a bypass circuit that connects the discharge side and the suction side of the compressor and causes the refrigerant discharged from the compressor to be sucked into the compressor again. 1. The vehicle air conditioner according to item 1.

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