Air conditioning device for vehicle

Abstract

Provided is a vehicle air-conditioning device capable of improving the measurement accuracy of the air temperature on the downwind side of a heater core without adding a sensor. A control device (200) is capable of performing control in a hot-gas heating mode in which a portion of a refrigerant passing through a compressor (11) flows to a heater core (12) and the remaining refrigerant flows to a bypass path. The air temperature (Thp) on the downwind side of the heater core (12) is calculated on the basis of the temperature (Tcxin) of the refrigerant flowing into the inlet side (12a) of the heater core (12), the temperature (Tci) of the refrigerant flowing out from the outlet side of the heater core (12), the degree of superheat of the refrigerant flowing out from the outlet side of the heater core (12), and SHout.

Description

Technical Field

[0001] This invention relates to an automotive air conditioning device. Background Technology

[0002] As an air conditioning system for electric vehicles (EVs) that do not have a heat source such as an engine or combustion system, and for vehicles with relatively low heat from the combustion system, air conditioning systems that use heat pumps are known.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 672137 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] The purpose of this invention is to provide an automotive air conditioning device that can improve the accuracy of measuring the air temperature on the downwind side of the heater core without adding an additional sensor.

[0008] Technical solutions adopted to solve technical problems

[0009] According to one aspect of the present invention, an automotive air conditioning device includes: a refrigerant circuit, the refrigerant circuit including: a compressor; a heater core configured to heat air supplied to the vehicle interior; a pressure reducing device; a low-temperature side heat exchanger for the refrigerant to absorb heat from a heat carrier absorbing heat from an on-board heating device; and a bypass path configured to circulate the refrigerant in a storage tank and allow the refrigerant passing through the compressor to bypass the heater core and flow into the suction side of the compressor; and a control device capable of controlling a hot-gas heating mode in which a portion of the refrigerant passing through the compressor flows to the heater core and the remaining refrigerant flows to the bypass path, the control device calculating the air temperature on the downwind side of the heater core in the hot-gas heating mode based on the temperature of the refrigerant flowing into the inlet side of the heater core, the temperature of the refrigerant flowing out from the outlet side of the heater core, and the superheat of the refrigerant flowing out from the outlet side of the heater core.

[0010] Invention Effects

[0011] According to the present invention, an automotive air conditioning device is provided that can improve the measurement accuracy of the air temperature on the downwind side of the heater core without adding additional sensors. Attached Figure Description

[0012] Figure 1This is a diagram showing an outline of a vehicle air conditioning unit, and also a diagram showing an example of the state of the vehicle air conditioning unit when performing hot air heating.

[0013] Figure 2 This is a block diagram illustrating an example of a control device in an automotive air conditioning system.

[0014] Figure 3 This is a flowchart illustrating an example of the steps involved in calculating heating capacity when a vehicle air conditioning system is operating in hot air heating mode. Detailed Implementation

[0015] [Structure of automotive air conditioning system]

[0016] <Overview of automotive air conditioning systems>

[0017] The vehicle air conditioning device of this embodiment is configured to improve the accuracy of measuring the air temperature on the downwind side of the heater core without adding additional sensors.

[0018] Figure 1 This is an explanatory diagram showing a general outline of the structure of the vehicle air conditioning unit 1 according to this embodiment.

[0019] The vehicle air conditioning unit 1 includes a refrigerant circuit 10 configured to circulate refrigerant. The refrigerant is not limited to this; for example, hydrofluoroolefins (HFCs) can be used. Additionally, the vehicle air conditioning unit 1 includes a battery temperature regulation circuit 40 configured to circulate a heat carrier fluid such as coolant.

[0020] Additionally, the vehicle air conditioning unit 1 includes an HVAC (Heating, Ventilation and Air Conditioning) unit 100. Furthermore, the vehicle air conditioning unit 1 includes a control device 200 (see reference) that controls the operation of various sensors or parts of the vehicle air conditioning unit 1. Figure 2 The vehicle air conditioning unit 1 controls its operation based on the detection values ​​of various sensors and various requirements.

[0021] <Refrigerant Circuit>

[0022] The refrigerant circuit 10 includes: a compressor 11 that compresses gaseous refrigerant into high temperature and high pressure and discharges it; a heater core 12 housed in the housing 110 of the HVAC unit 100 and heats the air supplied to the vehicle interior; pressure reducing devices 13a, 13b, 13c, and 13d, such as an expansion valve, that expands liquid refrigerant to low pressure; a low-temperature heat exchanger 14 that absorbs heat by evaporating low-temperature, low-pressure liquid refrigerant; a storage tank 15; a cooler core 16 housed in the housing 110 of the HVAC unit 100 and cools the air supplied to the vehicle interior; and a radiator 17 that serves as an outdoor heat exchanger. The refrigerant circuit 10 is configured to function as a heat pump that circulates and repeatedly compresses, condenses, expands, and evaporates the refrigerant.

[0023] In the low-temperature heat exchanger 14, the refrigerant exchanges heat with a heat carrier circulating in the battery temperature regulation circuit 40. In one illustrated example, the low-temperature heat exchanger 14 includes a refrigerant passage 14a through which the refrigerant circulating in the refrigerant circuit 10 passes and a heat carrier passage 14b through which the heat carrier circulating in the battery temperature regulation circuit 40 passes.

[0024] The various elements of the refrigerant circuit 10 are connected through refrigerant flow paths 10a, 10b, 10c, 10e, 10f, 10g, 10j, 10k, 10m, 10n, 10p, 10q, 10r, 10s, 10t, 10u, 10v, and 10w.

[0025] The discharge side 11a of the compressor 11 is connected to the inlet side 12a of the heater core 12 via the refrigerant flow path 10a, the bifurcation point 18a and the downstream refrigerant flow path 10b connected thereto.

[0026] The discharge side 11a of compressor 11 is connected to the inlet side 15a of storage tank 15 via refrigerant flow path 10a, branch point 18a, refrigerant flow path 10c, junction point 19a, refrigerant flow path 10e, junction point 19b, and downstream refrigerant flow path 10f. A pressure reducing device 13a is provided along the path of refrigerant flow path 10c.

[0027] The outlet side 15b of the storage tank 15 is connected to the suction side 11b of the compressor 11 via the refrigerant flow path 10g connected thereto.

[0028] The outlet side 12b of the heater core 12 is connected to the inlet side 16a of the cooler core 16 via a refrigerant flow path 10j, a branch point 18b, a refrigerant flow path 10k, a confluence point 19d, a refrigerant flow path 10m, a branch point 18c, and a downstream refrigerant flow path 10n. A flow path opening / closing valve 20a is provided along the path of the refrigerant flow path 10k. A pressure reducing device 13b is provided along the path of the refrigerant flow path 10n.

[0029] The outlet side 16b of the cooler core 16 is connected to the inlet side 15a of the storage tank 15 via refrigerant flow path 10p, junction point 19e, refrigerant flow path 10q, junction point 19a, refrigerant flow path 10e, junction point 19b, and downstream refrigerant flow path 10f. A backflow prevention valve 21b is provided in the path of refrigerant flow path 10q to prevent refrigerant from flowing back into the cooler core 16.

[0030] The outlet side 12b of the heater core 12 is connected to the inlet of the refrigerant passage 14a of the low-temperature heat exchanger 14 via the refrigerant flow path 10j, the branch point 18b, the refrigerant flow path 10k, the confluence point 19d, the refrigerant flow path 10m, the branch point 18c, and the downstream refrigerant flow path 10r. A pressure reducing device 13c is provided along the path of the refrigerant flow path 10r.

[0031] The outlet of the refrigerant passage 14a of the low-temperature heat exchanger 14 is connected to the inlet side 15a of the storage tank 15 via the refrigerant flow path 10s connected thereto, the junction point 19b, and the downstream refrigerant flow path 10f. A flow path opening and closing valve 20d is provided on the path of the refrigerant flow path 10s.

[0032] The outlet side 12b of the heater core 12 is connected to the inlet side 17a of the radiator 17 via the refrigerant flow path 10j connected thereto, the bifurcation point 18b, and the downstream refrigerant flow path 10t. A pressure reducing device 13d is provided in the path of the refrigerant flow path 10t.

[0033] The outlet side 17b of the radiator 17 is connected to the inlet side 15a of the storage tank 15 via a refrigerant flow path 10u, a branch point 18d, a refrigerant flow path 10v, a junction point 19e, a refrigerant flow path 10q, a junction point 19a, a refrigerant flow path 10e, a junction point 19b, and a downstream refrigerant flow path 10f. A flow path opening and closing valve 20b is provided along the path of the refrigerant flow path 10v.

[0034] The outlet side 17b of the radiator 17 is connected to the inlet side 16a of the cooler core 16 via a refrigerant flow path 10u, a branch point 18d, a refrigerant flow path 10w, a confluence point 19d, a refrigerant flow path 10m, a branch point 18c, and a downstream refrigerant flow path 10n. A backflow prevention valve 21c is provided in the path of the refrigerant flow path 10w to prevent refrigerant from flowing back into the radiator 17.

[0035] The outlet side 17b of the radiator 17 is connected to the inlet of the refrigerant passage 14a of the low-temperature heat exchanger 14 via the refrigerant flow path 10u, the branch point 18d, the refrigerant flow path 10w, the confluence point 19d, the refrigerant flow path 10m, the branch point 18c and the downstream refrigerant flow path 10r connected thereto.

[0036] <Battery Temperature Regulation Circuit>

[0037] The battery temperature regulation circuit 40, which serves as a temperature regulation circuit for an on-board heating device, includes the heat carrier passage 14b of the aforementioned low-temperature side heat exchanger 14 and the battery 41, which serves as an on-board heating device. A battery temperature regulation unit for regulating the temperature of the battery 41 is provided in the battery 41. The battery temperature regulation circuit 40 is capable of regulating the temperature of the battery 41.

[0038] In addition, the same structure as the battery temperature regulation circuit 40 can also be applied to other vehicle equipment temperature regulation circuits, which have a vehicle equipment temperature regulation unit for regulating the temperature of other vehicle equipment that also require temperature regulation, not just the battery.

[0039] In one illustrated example, the elements of the battery temperature regulation loop 40 are connected by heat transfer fluid flow paths 40a and 40b. The inlet side 41a of the battery 41 is connected to the outlet of the heat transfer fluid passage 14b of the low-temperature heat exchanger 14 via the heat transfer fluid flow path 40a. The outlet side 41b of the battery 41 is connected to the inlet of the heat transfer fluid passage 14b of the low-temperature heat exchanger 14 via the heat transfer fluid flow path 40b.

[0040] Along the flow path 40b of the heat carrier, a circulation pump P40 and a heat carrier heating device 42 are sequentially arranged from the upstream side. The heat carrier can be circulated by the circulation pump P40 to regulate the temperature of the battery 41.

[0041] <HVAC Unit>

[0042] The heater core 12 and cooler core 16 of the refrigerant circuit 10 are housed within the housing 110 of the HVAC unit 100. The housing 110 forms the outer shell of the HVAC unit 100 and forms an airflow path 120 inside it.

[0043] Furthermore, the HVAC unit 100 includes an air intake unit 130. The air intake unit 130 can lock either an external air intake for introducing outside air or an internal air intake for introducing inside air, thus switching the air introduced into the housing 110 to either outside air (external air intake) or inside air (internal air recirculation). Moreover, the HVAC unit 100 includes a blower 140, which is disposed adjacent to the air intake unit 130 to deliver the air introduced into the housing 110 to the airflow path 120. The blower 140 delivers air that has undergone heat exchange through the heater core 12 or the cooler core 16 into the vehicle interior.

[0044] A cooler core 16 is provided on the upstream side of the airflow path 120. Furthermore, a heater core passage 121 and a bypass passage 122 are formed side-by-side on the downstream side of the airflow path 120. A heater core 12 is provided in the heater core passage 121. Therefore, if air introduced into the housing 110 is guided to the heater core passage 121, the air is ventilated to the cooler core 16 and then to the heater core 12. On the other hand, if air introduced into the housing 110 is guided to the bypass passage 122, the air is ventilated to the cooler core 16 and then bypasses the heater core 12. The ratio of air passing through the heater core passage 121 to air passing through the bypass passage 122 is adjusted by the air mixing baffle 150.

[0045] <Control Device>

[0046] Figure 2 This is an explanatory diagram showing a general structural example of the control device 200 of the vehicle air conditioning unit 1 according to this embodiment.

[0047] The control unit 200 controls the operation of various sensors and components of the vehicle air conditioning system 1. The control unit 200 is an air conditioning ECU (Electronic Control Unit) used to execute various control modes of the vehicle air conditioning system 1. The various control modes executed by the control unit 200 include a hot air heating mode.

[0048] Various sensors input detection information to the control device 200. In hot gas heating mode, detection information from the supply air temperature sensor 210, the external gas temperature sensor 220, the refrigerant temperature sensor 230, the refrigerant pressure sensor 240, and the vehicle interior temperature sensor 250 is input to the control device 200. The refrigerant temperature sensor 230 consists of multiple sensors that detect the refrigerant temperature at various points in the refrigerant circuit 10, including an inlet-side refrigerant temperature sensor 230a that detects the refrigerant temperature at the inlet side 12a of the heater core 12 and an outlet-side refrigerant temperature sensor 230b that detects the refrigerant temperature at the outlet side 12b of the heater core 12. The refrigerant pressure sensor 240 is composed of multiple sensors that detect the refrigerant pressure at various points in the refrigerant circuit 10, including an inlet-side refrigerant pressure sensor 240a that detects the refrigerant pressure at the inlet side 12a of the heater core 12 and an outlet-side refrigerant pressure sensor 240b that detects the refrigerant pressure at the outlet side 12b of the heater core 12.

[0049] Based on detection information from various sensors, the control device 200 selects the path in the refrigerant circuit 10 by opening and closing the pressure reducing devices 13a-13d or the flow path opening and closing valves 20a and 20b. Simultaneously, the control device 200 controls the operation of the compressor 11, the blower 140, the air mixing baffle 150, the circulating pump P40, and the pressure reducing devices 13a-13d, and also controls the heat dissipation of the refrigerant. Furthermore, the control device 200 calculates the measured heating capacity and the target heating capacity in the hot air heating mode by appropriately using detection information from the supply air temperature sensor 210, the vehicle interior temperature sensor 250, the inlet-side refrigerant temperature sensor 230a, the inlet-side refrigerant pressure sensor 240a, the outlet-side refrigerant temperature sensor 230b, and the inlet-side refrigerant pressure sensor 240a.

[0050] [Operation of the vehicle's air conditioning system]

[0051] The specific operation of the vehicle air conditioning unit 1 in this embodiment will be explained.

[0052] <Hot Gas Heating Mode>

[0053] Figure 1 The state of the vehicle air conditioning unit 1 is shown when the outside air temperature is extremely low. At this time, the vehicle interior is heated by executing the hot air heating mode.

[0054] In hot gas heating mode, control device 200 sets pressure reducing devices 13b and 13d to be fully closed and opens flow path opening and closing valves 20a and 20b.

[0055] Thus, the refrigerant discharged from the compressor 11 flows through refrigerant flow paths 10a and 10b and passes through the heater core 12. The refrigerant passing through the heater core 12 flows through refrigerant flow paths 10j, 10k, 10m, and 10r and through the refrigerant passage 14a of the low-temperature heat exchanger 14. The refrigerant passing through the refrigerant passage 14a of the low-temperature heat exchanger 14 flows through refrigerant flow paths 10s and 10f and flows into the storage tank 15. The refrigerant flowing into the storage tank 15 flows through refrigerant flow path 10g and flows into the compressor 11. That is, through the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10r, 10s, 10f, and 10g, a circulation path is formed for the refrigerant passing through the compressor 11 to circulate through the heater core 12.

[0056] Furthermore, the refrigerant discharged from the compressor 11 flows through refrigerant flow paths 10a, 10c, 10e, and 10f and into the storage tank 15. The refrigerant flowing into the storage tank 15 flows through refrigerant flow path 10g and into the compressor 11. That is, through the refrigerant flow paths 10a, 10c, 10d, 10e, 10f, and 10g, a bypass path is formed for the refrigerant passing through the compressor 11 to bypass the heater core 12.

[0057] The control device 200 adjusts the flow rate of the pressure reducing device 13a so that a portion of the refrigerant discharged from the compressor 11 flows to the heater core 12, while the remaining refrigerant flows to the bypass path. As a result, the heat from the refrigerant dissipated in the heater core 12 heats the vehicle interior. Furthermore, the refrigerant flowing to the bypass path returns to the suction side 11b of the compressor 11 at a higher temperature than the refrigerant that passed through the heater core 12. Therefore, in hot gas heating mode, even if the external gas temperature is extremely low, the temperature of the refrigerant discharged from the compressor 11 can be increased to maintain heating capacity.

[0058] [Controls in automotive air conditioning systems]

[0059] Next, use Figure 3 This will explain the control processing implemented by the control device 200 in the vehicle air conditioning unit 1.

[0060] In hot air heating mode, the control device 200 calculates the heating capacity required to achieve the cabin temperature set by the occupant, i.e., the target heating capacity TGQh, using the following formula (1). On the other hand, it calculates the actual heating capacity, i.e., the measured value of the heating capacity Qhp, using the following formula (2).

[0061] Then, the control device 200 compares the two to determine whether the measured heating capacity Qhp has reached the target heating capacity TGQh. As a result, when the measured heating capacity Qhp has not reached the target heating capacity TGQh, the control device 1 controls each part to calculate the changes in the measured heating capacity Qhp, thereby achieving the target heating capacity TGQh.

[0062] TGQh = (THO - Te) × Ga (1)

[0063] TGQh: Target heating capacity (kW)

[0064] THO: Air temperature on the downwind side of the target heater core (°C)

[0065] Te: Air temperature on the windward side of the heater core (°C)

[0066] Ga: Airflow volume (m³) through airflow path 120 3 / s)

[0067] Qhp = (Thp - Te) × Ga (2)

[0068] Qhp: Measured heating capacity (kW)

[0069] Thp: Air temperature (°C) on the downwind side of the heater core.

[0070] Te: Air temperature on the windward side of the heater core (°C)

[0071] Ga: Airflow volume (m³) through airflow path 120 3 / s)

[0072] Furthermore, the target heater core downwind air temperature THO is calculated based on the difference between the set temperature inside the vehicle and the measured temperature inside the vehicle when calculating the target heating capacity. Additionally, the air volume Ga is estimated based on factors such as the blower voltage BLV of the blower 140.

[0073] <Calculation and processing of measured heating capacity Qhp>

[0074] Figure 3 This is a flowchart illustrating an example of the calculation process performed by the control device 200 to obtain the measured heating capacity value Qhp. The control device 200 executes... Figure 3 The process shown involves calculating the measured heating capacity Qhp using the formula in (2) above, based on the method of the present invention for calculating the air temperature Thrp on the downwind side of the heater core. Hereinafter, refer to... Figure 3 Please provide a detailed explanation.

[0075] like Figure 3 As shown, the control device 200 calculates the superheat SHout of the refrigerant flowing out from the outlet side 12b of the heater core 12 based on the temperature and pressure of the outlet side 12b of the heater core 12 (S1).

[0076] The superheat SHout is determined, for example, based on the pressure at the outlet side 12b of the heater core 12, and is calculated by subtracting the saturation temperature from the temperature at the outlet side 12b of the heater core 12. The control device 200 stores a data table that correlates the pressure at the outlet side 12b of the heater core 12 with the saturation temperature based on pH graph data. By retrieving this data table, the saturation temperature can be determined based on the pressure at the outlet side 12b of the heater core 12. Alternatively, the saturation temperature can be calculated using a formula based on pH graph data. Furthermore, the superheat SHout of the refrigerant at the outlet side 12b of the heater core 12 can also be calculated based on the pressure at the inlet side 12a of the heater core 12 and the temperature at the outlet side 12b of the heater core 12.

[0077] Next, the control device 200 determines whether the calculated superheat SHout is above the specified value α (α>0) (S2).

[0078] Here, due to the detection error of the outlet-side refrigerant temperature sensor 230b or the outlet-side refrigerant pressure sensor 240b, it is difficult to accurately detect that the superheat SHout is 0. Therefore, due to the sensor detection error, even if the superheat SHout is 0 or higher, the refrigerant inside the heater core 12 may still contain a portion that dissipates latent heat. That is, even if the superheat SHout is 0 or higher, the refrigerant inside the heater core 12 may still contain two-phase refrigerant. Therefore, by determining whether the superheat SHout is 0 or higher, it is difficult to accurately determine whether the refrigerant inside the heater core 12 contains two-phase refrigerant. Therefore, in this embodiment, considering the sensor detection error, a predetermined value α (α > 0) is set as the determination value of the superheat SHout used to determine whether the refrigerant inside the heater core 12 contains two-phase refrigerant, which is presumed to mean that the refrigerant inside the heater core 12 does not contain two-phase refrigerant. Then, by setting the superheat SHin of the refrigerant flowing into the inlet side 12a of the heater core 12 to a predetermined value α or higher, and determining whether the superheat SHout is a predetermined value α (α > 0) or higher, it is presumed whether the refrigerant inside the heater core 12 contains a two-phase refrigerant. Specifically, if the superheat SHout is a predetermined value α or higher, then it does not contain a two-phase refrigerant; however, if the superheat SHout is lower than the predetermined value α, even if superheat exists, it is presumed that it contains a two-phase refrigerant. Furthermore, a two-phase refrigerant is a refrigerant composed of a gaseous refrigerant and a liquid refrigerant that do not have superheat. Additionally, a gaseous refrigerant can also be called a vapor-phase refrigerant.

[0079] Alternatively, it can be inferred whether the refrigerant in the heater core 12 contains two-phase refrigerant by determining whether the superheat SHout exceeds 0.

[0080] Then, if the control device 200 determines that the superheat SHout is above the specified value α (S2: Yes), it presumes that the refrigerant inside the heater core 12 is entirely in a state of sensible heat dissipation and is only a gaseous refrigerant. In other words, it presumes that the refrigerant inside the heater core 12 does not contain two-phase refrigerant. Therefore, the control device 200 presumes the proportion of two-phase refrigerant in the refrigerant inside the heater core 12, i.e., the two-phase refrigerant ratio MO_rate, to 0 (S3).

[0081] Furthermore, if the control device 200 determines that the superheat SHout is lower than the specified value α (S2: No), it presumes that the refrigerant inside the heater core 12 is in a state that includes latent heat dissipation and contains two-phase refrigerant. Therefore, the control device 200 presumes the two-phase refrigerant ratio MO_rate based on the value of the superheat SHout (S4).

[0082] The control device 200 stores a data table that correlates the value of superheat SHout with the two-phase refrigerant ratio MO_rate. In this data table, when the superheat SHout represents a lower limit, the two-phase refrigerant ratio MO_rate represents its maximum value, i.e., the maximum two-phase refrigerant ratio MO_max_rom. Furthermore, as the superheat SHout increases, the two-phase refrigerant ratio MO_rate decreases by a certain proportion. When the superheat SHout represents a value above a predetermined value α, it represents the minimum value of the two-phase refrigerant ratio MO_rate, i.e., 0. This is because when the superheat SHout increases, the proportion of gaseous refrigerant in the heater core 12 increases, and the proportion of two-phase refrigerant decreases. When the superheat SHout reaches a value above the predetermined value α, the refrigerant in the heater core 12 is only gaseous refrigerant. Then, the control device 200 can estimate the two-phase refrigerant ratio MO_rate by retrieving this data table based on the value of superheat SHout.

[0083] Next, after estimating the two-phase refrigerant ratio MO_rate, the control device 200 calculates the air temperature Thp (S5) on the downwind side of the heater core using the following formula (3).

[0084] Thp=(1-MMO_rate)×Tci+MO_rate×(Tcxin+Tci) / 2 (3)

[0085] Thp: Air temperature (°C) on the downwind side of the heater core.

[0086] MO_rate: Two-phase refrigerant ratio

[0087] Tci: Temperature (°C) of the refrigerant flowing out from the outlet side of the heater core.

[0088] Tcxin: Temperature (°C) of the refrigerant flowing into the inlet side of the heater core.

[0089] According to the calculation formula (3) above, the part (1 - MO_rate) × Tci is the calculation part of the air temperature Thp on the downwind side of the heater core based on the proportion of gaseous refrigerant. In addition, the part MO_rate × (Tcxin + Tci) / 2 is the calculation part of the air temperature Thp on the downwind side of the heater core based on the proportion of two-phase refrigerant. Therefore, in the calculation formula (3) above, the air temperature Thp on the downwind side of the heater core can be calculated based on the proportion of gaseous refrigerant and the proportion of two-phase refrigerant.

[0090] Therefore, compared with the case where only the calculation formula corresponding to the gaseous refrigerant or the calculation formula corresponding to the two-phase refrigerant is used to calculate the air temperature Thp on the downwind side of the heater core, the calculation accuracy of the air temperature Thp on the downwind side of the heater core can be improved by using the calculation formula (3) above.

[0091] Furthermore, if the refrigerant in the heater core 12 is only gaseous refrigerant, and the two-phase refrigerant ratio MO_rate = 0, then the temperature Tci of the refrigerant flowing out from the outlet side 12b of the heater core 12 is presumed to be the air temperature Thrp on the downwind side of the heater core. Alternatively, if the proportion of two-phase refrigerant in the refrigerant within the heater core 12 is at its maximum, and the two-phase refrigerant ratio MO_rate = the maximum two-phase refrigerant ratio MO_max_rom, then the air temperature Thrp on the downwind side of the heater core is presumed based on considering the maximum two-phase refrigerant ratio.

[0092] Next, the control device 200 uses the air temperature Thp on the downwind side of the heater core calculated by the formula shown in (3) above to calculate the measured value of heating capacity Qhp (S6) by the formula shown in (2) above.

[0093] As described above, by estimating whether the refrigerant inside the heater core 12 is in a state of sensible heat dissipation and is only a gaseous refrigerant, or the refrigerant inside the heater core 12 is in a state of including latent heat dissipation and contains two phases of refrigerant, based on the superheat SHout of the outlet side 12b of the heater core 12, it is possible to consider the state of the refrigerant inside the heater core 12 to calculate the air temperature on the downwind side of the heater core 12. This can improve the accuracy of measuring the air temperature on the downwind side of the heater core 12 without adding a sensor to measure the air temperature on the downwind side of the heater core 12.

[0094] Furthermore, by estimating the ratio of the two-phase refrigerant inside the heater core 12 based on the superheat SHout of the outlet side 12b of the heater core 12, the accuracy of the calculation of the air temperature on the downwind side of the heater core 12 can be improved without the need for additional dedicated sensors.

[0095] Furthermore, the present invention is preferably implemented, for example, when activating the hot gas heating mode. For example, activating the hot gas heating mode can be divided into three stages.

[0096] In the first stage, air is not supplied through the blower 140, and the refrigerant flows to the heater core 12. At this time, since the heater core 12 has been sufficiently cooled, a portion of the refrigerant condenses even though air is not supplied through the blower 140. Therefore, the refrigerant in the heater core 12 consists of gaseous refrigerant and two-phase refrigerant. In other words, the refrigerant in the heater core 12 is in a state that includes both sensible heat dissipation and latent heat dissipation. At this time, although the superheat SHin of the inlet side 12a of the heater core 12 is above the specified value α, the superheat SHout of the outlet side 12b of the heater core 12 is below the specified value α. Therefore, based on the estimated ratio of two-phase refrigerant based on the superheat SHout, the air temperature Thp on the downwind side of the heater core is calculated using the above calculation formula (3).

[0097] In the second stage, for most of the period when air is finally supplied by the blower 140, no air is supplied by the blower 140, and the refrigerant flows through the heater core 12. At this time, since the heater core 12 is heated by the refrigerant, no refrigerant condensation occurs in the heater core 12. Therefore, only gaseous refrigerant exists as the refrigerant in the heater core 12. In other words, the refrigerant in the heater core 12 is only the portion that dissipates sensible heat. At this time, the superheat SHin of the inlet side 12a of the heater core 12 exceeds the specified value α, and the superheat SHout of the outlet side 12b of the heater core 12 also exceeds the specified value α. Therefore, based on the assumption that the ratio of the two-phase refrigerant is 0, the air temperature Thp on the downwind side of the heater core is calculated using the above calculation formula (3).

[0098] In the third stage, air is supplied by the blower 140, and refrigerant flows through the heater core 12. At this time, a portion of the refrigerant condenses due to the air supplied by the blower 140. Therefore, the refrigerant in the heater core 12 consists of gaseous refrigerant and two-phase refrigerant. In other words, the refrigerant in the heater core 12 is in a state that includes both sensible heat dissipation and latent heat dissipation. At this time, although the superheat SHin of the inlet side 12a of the heater core 12 is above the specified value α, the superheat SHout of the outlet side 12b of the heater core 12 is below the specified value α. Therefore, based on the estimated ratio of two-phase refrigerant based on the superheat SHout, the air temperature Thp on the downwind side of the heater core is calculated using the above calculation formula (3).

[0099] Thus, the start-up of the hot gas heating mode can be divided into three stages. In the first and third stages, the refrigerant in the heater core 12 contains two-phase refrigerant, but in the second stage, it is only gaseous refrigerant. That is, the refrigerant in the heater core 12 transitions between a state containing two-phase refrigerant and a state not containing two-phase refrigerant. Therefore, in the hot gas heating mode, by estimating whether two-phase refrigerant is contained based on the superheat SHout of the outlet side 12b of the heater core 12, and calculating the downwind air temperature Thrp of the heater core based on the estimated result, the calculation accuracy of the downwind air temperature Thrp of the heater core can be improved. Consequently, the calculation accuracy of the measured heating capacity Qhp can be improved.

[0100] In addition, as described above, the control device 200 controls the conditions used to calculate the measured value of heating capacity Qhp so that the measured value of heating capacity Qhp reaches the target heating capacity TGQh.

[0101] That is, when the air temperature Thrp on the downwind side of the heater core increases, the air volume of the blower 140 is increased to reduce the pressure and temperature of the refrigerant flowing through the heater core 12, and to maintain the measured value of heating capacity Qhp (kW), so that the measured value of heating capacity Qhp (kW) reaches the target heating capacity TGQh (kW).

[0102] In addition, when the air temperature Thrp on the downwind side of the heater core decreases, the air volume of the blower 140 is reduced to increase the pressure and temperature of the refrigerant flowing through the heater core 12, and the measured heating capacity Qhp (kW) is maintained so that the measured heating capacity Qhp (kW) reaches the target heating capacity TGQh (kW).

[0103] However, if the calculation accuracy of the air temperature Thrp on the downwind side of the heater core is low, that is, if the calculation accuracy of the measured heating capacity Qhp is low, the following problem will occur.

[0104] If the calculated air temperature (Thp) on the downwind side of the heater core is higher than the actual temperature, the airflow of the blower 140 increases, and the pressure and temperature rise of the refrigerant flowing through the heater core 12 slows down. Therefore, the time before the measured heating capacity (Qhp) reaches the target heating capacity (TGQh) increases, resulting in poorer rapid heating inside the vehicle.

[0105] On the other hand, if the detected air temperature (Thp) on the downwind side of the heater core is lower than the actual temperature, the airflow of the blower 140 decreases, and the pressure of the refrigerant flowing through the heater core 12 rises excessively. Therefore, since the temperature inside the vehicle is sometimes higher than the target, the controllability of the temperature inside the vehicle deteriorates.

[0106] However, by improving the calculation accuracy of the air temperature (Thp) on the downwind side of the heater core, the calculation accuracy of the measured heating capacity (Qhp) can be improved, thus enhancing the rapid heating of the vehicle interior and improving the temperature control within the vehicle interior.

[0107] [Effects of this implementation method]

[0108] (1) The vehicle air conditioning unit 1 includes: a refrigerant circuit 10, the refrigerant circuit 10 including: a compressor 11; a heater core 12 configured to heat the air supplied to the vehicle interior; pressure reducing devices 13a to 13e; a low-temperature heat exchanger 14 for the refrigerant to absorb heat from a heat carrier that is a vehicle-mounted heat-generating device, the battery 41; and a bypass path configured to circulate the refrigerant in a storage tank 15 and allow the refrigerant passing through the compressor 11 to bypass the heater core 12 and flow into the suction side 11b of the compressor 11; and a control device. The control device 200 is capable of controlling the flow of a portion of the refrigerant passing through the compressor 11 to the heater core 12 and the flow of the remaining refrigerant to the bypass path in the hot gas heating mode. In the hot gas heating mode, the control device 200 calculates the downwind air temperature Thrp of the heater core 12 based on the temperature Tcxin of the refrigerant flowing into the inlet side 12a of the heater core 12, the temperature Tci of the refrigerant flowing out from the outlet side of the heater core 12, and the superheat SHout of the refrigerant flowing out from the outlet side of the heater core 12.

[0109] Therefore, based on the superheat SHout of the outlet side 12b of the heater core 12, it can be inferred whether the refrigerant inside the heater core 12 is a gaseous refrigerant in a state of sensible heat dissipation or a refrigerant inside the heater core 12 that contains two phases of refrigerant and is in a state of latent heat dissipation. The state of the refrigerant inside the heater core 12 can be taken into account to calculate the downwind air temperature Thp of the heater core 12. This can improve the measurement accuracy of the downwind air temperature of the heater core 12 without adding a sensor to measure the downwind air temperature Thp of the heater core 12.

[0110] (2) The control device 200 estimates the proportion of the two-phase refrigerant in the refrigerant in the heater core 12 based on the superheat SHout of the refrigerant flowing out from the outlet side 12b of the heater core 12, and calculates the air temperature on the downwind side of the heater core 12 based on the proportion of the two-phase refrigerant, the temperature of the refrigerant flowing into the inlet side 12a of the heater core 12 and the temperature of the refrigerant flowing out from the outlet side 12b of the heater core 12.

[0111] Therefore, by estimating the ratio of the two-phase refrigerant inside the heater core 12 based on the superheat SHout of the outlet side 12b of the heater core 12, the accuracy of the calculation of the air temperature on the downwind side of the heater core 12 can be improved without the need for additional dedicated sensors.

[0112] The preferred embodiments have been shown above and the present invention has been described. However, the present invention is not limited to the foregoing embodiments, and it goes without saying that various changes can be made within the scope of the present invention.

[0113] Symbol Explanation

[0114] 1: Vehicle air conditioning unit; 10: Refrigerant circuit; 11: Compressor; 12: Heater core; 13a, 13b, 13c, 13d: Pressure reducing device; 14: Low-temperature side heat exchanger; 15: Storage tank; 16: Cooler core; 17: Radiator; 40: Battery temperature regulation circuit; 41: Battery; P40: Circulation pump; 100: HVAC unit; 110: Housing; 120: Airflow path; 121: Heater core passage; 122: Bypass passage; 150: Air mixing baffle.

Claims

1. A vehicle air conditioning unit, comprising: A refrigerant circuit, comprising: a compressor; a heater core configured to heat air supplied to the vehicle interior; a pressure reducing device; a low-temperature heat exchanger for the refrigerant to absorb heat from a heat carrier absorbed from onboard heating equipment; and a bypass path configured to circulate the refrigerant in a storage tank and allow refrigerant passing through the compressor to bypass the heater core and flow into the suction side of the compressor; and The control device, capable of directing a portion of the refrigerant passing through the compressor to the heater core and the remaining refrigerant to the bypass path in a hot gas heating mode, is characterized in that... In the hot gas heating mode, the control device calculates the air temperature on the downwind side of the heater core based on the temperature of the refrigerant flowing into the inlet side of the heater core, the temperature of the refrigerant flowing out from the outlet side of the heater core, and the superheat of the refrigerant flowing out from the outlet side of the heater core.

2. The vehicle air conditioning device as described in claim 1, characterized in that, The control device estimates the proportion of two-phase refrigerant in the refrigerant within the heater core based on the superheat of the refrigerant flowing out from the outlet side of the heater core, and calculates the air temperature on the downwind side of the heater core based on the proportion of the two-phase refrigerant, the temperature of the refrigerant flowing into the inlet side of the heater core, and the temperature of the refrigerant flowing out from the outlet side of the heater core.

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