Vehicle air conditioning system

Abstract

The present invention provides a vehicle air conditioning system that can reduce the target rotational speed of the compressor. [Solution] The system includes a heat exchange unit 200 that exchanges heat between the refrigerant flowing through the downstream path of the indoor condenser 12 and the refrigerant flowing through the downstream path of the pressure reducing device 13a located on the bypass path when hot gas heating operation is being performed. Therefore, the amount of refrigerant flowing through the bypass path can be reduced because the amount of refrigerant required for hot gas heating operation can be returned to the compressor 11 without increasing the amount of refrigerant flowing through the bypass path. Consequently, the target rotational speed of the compressor 11 can be reduced.

Description

Technical Field

[0001] The present invention relates to a vehicle air conditioner.

Background Art

[0002] As an air conditioner for an electric vehicle (EV: Electric Vehicle) that does not have a combustion heat source such as an engine or a vehicle with a small amount of heat from a combustion heat source, for example, a vehicle air conditioner capable of performing a hot gas heating operation in which a part of the refrigerant discharged from a compressor flows through a bypass path and the remaining refrigerant flows through a condenser is known (Patent Document 1). Also, a vehicle air conditioner provided with an injection circuit that branches a part of the refrigerant flowing through the condenser, decompresses it, and then exchanges heat with the remaining refrigerant and returns it to the compressor is known (Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a vehicle air conditioner that can reduce the target rotational speed of a compressor. [[ID=??]]

Means for Solving the Problems

[0005] It seems there is an error in the original text where the "??" is shown in the ID. It should probably be a correct ID number. Please check and correct if needed.According to one aspect of the present invention, a vehicle air conditioning system includes a compressor, a condenser, a pressure reducing device, an evaporator, and a refrigerant circuit having a bypass path through which a portion of the refrigerant discharged by the compressor bypasses the condenser and flows to the upstream side of the compressor, and a vehicle air conditioning system capable of performing hot gas heating operation in which a portion of the refrigerant discharged by the compressor flows through the bypass path and the remaining refrigerant flows to the condenser, and a heat exchange unit is provided to perform heat exchange between the refrigerant flowing through the path downstream of the condenser and the refrigerant flowing through the path downstream of the pressure reducing device located on the bypass path when hot gas heating operation is being performed. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a vehicle air conditioning system that can reduce the target rotational speed of the compressor. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows an example of the state of a vehicle's air conditioning system when hot gas heating operation is performed. [Modes for carrying out the invention]

[0008] [Configuration of a vehicle air conditioning system] <Overview of vehicle air conditioning systems> The vehicle air conditioning system of this embodiment is configured to reduce the target rotational speed of the compressor.

[0009] Figure 1 is an explanatory diagram illustrating a schematic example of the configuration of a vehicle air conditioning system 1 according to this embodiment.

[0010] The vehicle air conditioning system 1 includes a refrigerant circuit 10 configured to circulate a refrigerant. The refrigerant may be, but is not limited to, hydrofluoroolefins. The vehicle air conditioning system 1 also includes a battery temperature control circuit 40 configured to circulate a fluid heat transfer medium, such as coolant.

[0011] Furthermore, the vehicle air conditioning system 1 includes an HVAC (Heating, Ventilation, and Air Conditioning) unit 100. The vehicle air conditioning system 1 also includes a control device that controls the operation of various sensors and various parts of the vehicle air conditioning system 1. The operation of the vehicle air conditioning system 1 is controlled based on the detected values ​​of various sensors and various requests.

[0012] <Refrigerant Circuit> The refrigerant circuit 10 includes a compressor 11 that compresses gaseous refrigerant to high temperature and pressure before discharge, an indoor condenser 12 housed in the case 110 of the HVAC unit 100 and functioning as a condenser to heat the air supplied to the passenger compartment, pressure reducing devices 13a, 13b, 13c, 13d such as expansion valves that expand liquid refrigerant to low pressure, a low-temperature side heat exchanger 14 that evaporates the low-temperature and low-pressure liquid refrigerant to absorb heat, an accumulator 15, an evaporator 16 housed in the case 110 of the HVAC unit 100 and cooling the air supplied to the passenger compartment, an outdoor heat exchanger 17, and a heat exchange section 200. The refrigerant circuit 10 is configured to function as a heat pump that circulates the refrigerant and repeatedly compresses, condenses, expands, and evaporates it.

[0013] In the low-temperature heat exchanger 14, the refrigerant exchanges heat with the heat transfer medium circulating in the battery temperature control circuit 40. In one example shown in the figure, 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 transfer medium passage 14b through which the heat transfer medium circulating in the battery temperature control circuit 40 passes.

[0014] The discharge side 11a of the compressor 11 is connected to the inlet side 12a of the indoor condenser 12 via the refrigerant flow path 10a, the branch point 18a, and the downstream refrigerant flow path 10b connected thereto.

[0015] Furthermore, the discharge side 11a of the compressor 11 is connected to the inlet side 15a of the accumulator 15 via the refrigerant flow path 10a, branch point 18a, refrigerant flow path 10c, confluence point 19a, refrigerant flow path 10e, confluence point 19b, and the downstream refrigerant flow path 10f. A pressure reducing device 13a is installed along the path of the refrigerant flow path 10c.

[0016] The outlet side 15b of the accumulator 15 is connected to the suction side 11b of the compressor 11 via a refrigerant flow path 10g connected thereto. In other words, the accumulator 15 is located downstream of the low-temperature heat exchanger 14 and upstream of the compressor 11.

[0017] The outlet side 12b of the indoor condenser 12 is connected to the inlet side 16a of the evaporator 16 via the refrigerant flow path 10j, branch point 18b, refrigerant flow path 10k, confluence point 19d, refrigerant flow path 10m, branch point 18c, and the downstream refrigerant flow path 10n. A flow path shut-off valve 20a is installed along the path of the refrigerant flow path 10k. A pressure reducing device 13b is installed along the path of the refrigerant flow path 10n.

[0018] The outlet side 16b of the evaporator 16 is connected to the inlet side 15a of the accumulator 15 via the refrigerant flow path 10p, confluence point 19e, refrigerant flow path 10q, confluence point 19a, refrigerant flow path 10e, confluence point 19b, and the downstream refrigerant flow path 10f. A backflow prevention valve 21b is installed in the path of the refrigerant flow path 10q to prevent backflow of refrigerant into the evaporator 16.

[0019] Furthermore, the outlet side 12b of the indoor condenser 12 is connected to the inlet of the refrigerant passage 14a of the low-temperature heat exchanger 14 via the refrigerant flow path 10j, branch point 18b, refrigerant flow path 10k, confluence point 19d, refrigerant flow path 10m, branch point 18c, and the downstream refrigerant flow path 10r. A pressure reducing device 13c is installed along the path of the refrigerant flow path 10r.

[0020] The outlet of the refrigerant passage 14a of the low-temperature side heat exchanger 14 is connected to the inlet side 15a of the accumulator 15 via the refrigerant flow path 10s connected thereto, the confluence point 19b, and the refrigerant flow path 10f downstream thereof. A flow path opening / closing valve 20d is installed on the path of the refrigerant flow path 10s.

[0021] Also, the outlet side 12b of the indoor condenser 12 is connected to the inlet side 17a of the outdoor heat exchanger 17 via the refrigerant flow path 10j connected thereto, the branch point 18b, and the refrigerant flow path 10t downstream thereof. A pressure reducing device 13d is installed on the path of the refrigerant flow path 10t.

[0022] The outlet side 17b of the outdoor heat exchanger 17 is connected to the inlet side 15a of the accumulator 15 via the refrigerant flow path 10u connected thereto, the branch point 18d, the refrigerant flow path 10v, the confluence point 19e, the refrigerant flow path 10q, the confluence point 19a, the refrigerant flow path 10e, the confluence point 19b, and the refrigerant flow path 10f downstream thereof. A flow path opening / closing valve 20b is installed on the path of the refrigerant flow path 10v.

[0023] Also, the outlet side 17b of the outdoor heat exchanger 17 is connected to the inlet side 16a of the evaporator 16 via the refrigerant flow path 10u connected thereto, the branch point 18d, the refrigerant flow path 10w, the confluence point 19d, the refrigerant flow path 10m, the branch point 18c, and the refrigerant flow path 10n downstream thereof. A backflow prevention valve 21c for preventing the backflow of the refrigerant to the outdoor heat exchanger 17 is installed on the path of the refrigerant flow path 10w.

[0024] The outlet side 17b of the outdoor heat exchanger 17 is connected to the inlet of the refrigerant passage 14a of the low-temperature side heat exchanger 14 via the refrigerant flow path 10u connected thereto, the branch point 18d, the refrigerant flow path 10w, the confluence point 19d, the refrigerant flow path 10m, the branch point 18c, and the refrigerant flow path 10r downstream thereof.

[0025] In this embodiment, the refrigerant flow path 10k downstream of the indoor condenser 12 and the refrigerant flow path 10c downstream of the pressure reducing device 13a and upstream of the accumulator 15 are arranged to form a double-pipe structure with the two flow paths adjacent to each other. The portion where the refrigerant flow paths 10k and 10c are double-pipe (dotted line portion in the figure) is a heat exchange section 200 capable of exchanging heat with the refrigerant.

[0026] <Battery temperature control circuit> The battery temperature control circuit 40, which serves as a temperature control circuit for an in-vehicle heating device, includes the heat transfer medium passage 14b of the low-temperature side heat exchanger 14 described above, and the battery 41, which serves as an in-vehicle heating device. The battery 41 is provided with a battery temperature control unit for controlling the temperature of the battery 41. The battery temperature control circuit 40 can be used to adjust the temperature of the battery 41.

[0027] Furthermore, a configuration similar to that of the battery temperature control circuit 40 can be applied not only to batteries but also to other in-vehicle equipment temperature control circuits that have an in-vehicle equipment temperature control unit for controlling the temperature of other in-vehicle equipment that similarly requires temperature control.

[0028] In the example shown in the figure, each element of the battery temperature control circuit 40 is connected by heat transfer fluid passages 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 side heat exchanger 14 by the heat transfer fluid passage 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 side heat exchanger 14 by the heat transfer fluid passage 40b.

[0029] Along the path of the heat transfer medium flow path 40b, a circulation pump P40 and a heat transfer medium heating device 42 are installed in order from the upstream side. The heat transfer medium can be circulated by the circulation pump P40, and the temperature of the battery 41 can be adjusted.

[0030] <HVAC Unit> The indoor condenser 12 and evaporator 16 of the refrigerant circuit 10 are housed within the case 110 of the HVAC unit 100. The case 110 forms the outer shell of the HVAC unit 100 and also forms an air passage 120 inside.

[0031] Furthermore, the HVAC unit 100 has an intake unit 130. The intake unit 130 switches the air introduced into the case 110 between outside air (outside air intake) and inside air (inside air circulation) by closing either the outside air intake for introducing outside air or the inside air intake for introducing inside air. In addition, the HVAC unit 100 has a blower 140 installed adjacent to the intake unit 130 so that the air introduced into the case 110 is supplied to the air passage 120. The blower 140 blows air that undergoes heat exchange in the interior condenser 12 and evaporator 16 into the interior of the vehicle.

[0032] An evaporator 16 is installed on the upstream side of the airflow passage 120. Downstream of the airflow passage 120, a heater core passage 121 and a bypass passage 122 are formed in parallel. The indoor condenser 12 is located in the heater core passage 121. Therefore, when air introduced into the case 110 is guided to the heater core passage 121, the air is passed through the evaporator 16 and then through the indoor condenser 12. On the other hand, when air introduced into the case 110 is guided to the bypass passage 122, the air is passed through the evaporator 16 and then bypasses the indoor condenser 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 mix damper 150. In other words, the air mix damper 150 controls the flow rate of air passing through the indoor condenser 12.

[0033] [Operation of the vehicle's air conditioning system] The specific operation of the vehicle air conditioning system 1 according to this embodiment will be described below.

[0034] <Hot gas heating operation> Figure 1 shows the state of the vehicle air conditioning system 1 when the outside temperature is extremely low (for example, -20°C to -30°C). At this time, the vehicle interior is heated by running hot gas heating.

[0035] During hot gas heating operation, the refrigerant circuit 10 is set as follows: Pressure reducing devices 13a and 13c are opened, and pressure reducing devices 13b and 13d are fully closed. In addition, flow path valve 20a is opened, and flow path valve 20b is fully closed.

[0036] As a result, refrigerant passages 10a, 10b, 10j, 10k, 10m, 10r, 10s, 10f, and 10g are formed so that the refrigerant discharged from the compressor 11 flows into the compressor 11 after passing through the indoor condenser 12, the low-temperature heat exchanger 14, and the accumulator 15. At this time, the air mix damper 150 closes the bypass passage 122. As a result, the air heated by the heat of the refrigerant dissipated in the indoor condenser 12 passes through the heater core passage 121, and the vehicle interior is heated.

[0037] Furthermore, refrigerant flow paths 10a, 10b, 10c, 10e, 10f, and 10g are formed as bypass paths where a portion of the refrigerant discharged from the discharge side 11a of the compressor 11 bypasses the indoor condenser 12 and flows to the upstream side of the compressor 11.

[0038] Therefore, the bypass route includes a path through which the refrigerant discharged by the compressor 11 bypasses the indoor condenser 12, then passes through the pressure reducing device 13a, and flows downstream of the low-temperature heat exchanger 14 and upstream of the accumulator 15.

[0039] In hot gas heating operation, a portion of the refrigerant discharged by the compressor 11 can be routed to a bypass path, while the remaining refrigerant can be routed to the indoor condenser 12. The refrigerant flowing through the bypass path has a higher pressure when it returns to the suction side 11b of the compressor 11 compared to the refrigerant that passes through the indoor condenser 12. In hot gas heating operation, increasing the pressure of the refrigerant drawn in by the compressor 11 makes it possible to raise the temperature of the refrigerant discharged by the compressor 11, thereby improving heating capacity.

[0040] Furthermore, when hot gas heating operation is being performed, the heat exchange unit 200 exchanges heat between the refrigerant flowing through the path downstream of the indoor condenser 12 and the refrigerant flowing through the path downstream of the pressure reducing device 13a, which is located on the bypass path, and upstream of the accumulator 15.

[0041] If the heat exchange section 200 is not provided, it will be necessary to increase the amount of refrigerant flowing through the bypass path in order to return the amount of refrigerant required for hot gas heating operation to the suction side 11b of the compressor 11. In this case, the target rotational speed of the compressor 11 will increase as the amount of refrigerant increases.

[0042] Furthermore, as the amount of refrigerant from the bypass path increases, the flow velocity of the refrigerant increases. When the refrigerant passing through the bypass path is mixed with the refrigerant in the accumulator 15, the refrigerant may not be uniformly mixed within the accumulator 15. In this case, liquid refrigerant may leak out of the accumulator 15, and the compressor 11 may ingest the liquid refrigerant. If the compressor 11 ingests liquid refrigerant, it can lead to a failure of the compressor 11, thus reducing the reliability of the compressor 11.

[0043] However, in this embodiment, the heat exchange unit 200 can exchange heat between the refrigerant that has flowed out of the indoor condenser 12 and the refrigerant that has passed through the pressure reducing device 13a in the bypass path. As a result, it becomes possible to raise the temperature of the refrigerant on the return side of the bypass path (downstream of the pressure reducing device 13a), so that even if the amount of refrigerant flowing through the bypass path is reduced, the amount of refrigerant necessary for hot gas heating operation can be returned to the suction side 11b of the compressor 11. By reducing the amount of refrigerant flowing through the bypass path, the target rotational speed of the compressor 11 can be lowered, thereby reducing power consumption.

[0044] Furthermore, in this embodiment, the heat exchange unit 200 reduces the amount of refrigerant flowing through the bypass path, thereby suppressing an increase in the flow velocity of the refrigerant flowing into the accumulator 15, and enabling uniformity of the refrigerant within the accumulator 15. As a result, it is possible to prevent the compressor 11 from drawing in liquid refrigerant and stabilize the refrigerant drawn in by the compressor 11, thereby preventing failure of the compressor 11 and improving the reliability of the compressor 11.

[0045] [Differentiation] In this embodiment, a heat exchange section 200 with a double-tube structure was described as an example. However, the heat exchange section is not limited to this embodiment as long as it is possible to exchange heat between the refrigerant flowing in the path from the outlet of the pressure reducing device 13c to the inlet side 15a of the accumulator 15 and the refrigerant flowing in the path from the outlet side 12b of the indoor condenser 12 to the inlet of the pressure reducing device 13c, for example, by integrating the pressure reducing device 13a of the bypass path and the pressure reducing device 13c downstream of the indoor condenser 12.

[0046] [Effects of this embodiment] (1) A refrigerant circuit 10 comprising a compressor 11, an indoor condenser 12 as a condenser, a pressure reducing device 13a, a low-temperature side heat exchanger 14 as an evaporator, and a bypass path through which a portion of the refrigerant discharged by the compressor 11 bypasses the indoor condenser 12 as a condenser and flows to the upstream side of the compressor 11, In a vehicle air conditioning system 1 capable of performing hot gas heating operation, in which a portion of the refrigerant discharged by the compressor 11 is flowed through a bypass path and the remaining refrigerant is flowed to an indoor condenser 12 acting as a condenser, The system includes a heat exchange unit 200 that, when hot gas heating is being performed, exchanges heat between the refrigerant flowing through the downstream path of the indoor condenser 12 (which acts as a condenser) and the refrigerant flowing through the downstream path of the pressure reducing device 13a located on the bypass path. Therefore, when performing hot gas heating operation, heat exchange occurs between the refrigerant flowing out of the indoor condenser 12 (which acts as a condenser) and the refrigerant that has passed through the pressure reducing device 13a in the bypass path. This makes it possible to raise the temperature of the refrigerant that has passed through the pressure reducing device 13a in the bypass path, and it is possible to return the amount of refrigerant necessary for performing hot gas heating operation to the compressor 11 without increasing the amount of refrigerant flowing through the bypass path. As a result, the amount of refrigerant flowing through the bypass path can be reduced. Consequently, the target rotational speed of the compressor 11 can be reduced. This reduces power consumption.

[0047] (2) The accumulator 15 is placed on the path downstream of the low-temperature heat exchanger 14, which serves as the evaporator, and upstream of the compressor 11. The bypass path includes a route through which the refrigerant discharged by the compressor 11 bypasses the indoor condenser 12, which acts as a condenser, and then flows through the pressure reducing device 13a to the downstream side of the low-temperature heat exchanger 14, which acts as an evaporator, and to the upstream side of the accumulator 15. The heat exchange unit 200 exchanges heat between the refrigerant flowing through the downstream path of the indoor condenser 12, which acts as a condenser, and the refrigerant flowing through the downstream path of the pressure reducing device 13a, which is located on the bypass path, and the upstream path of the accumulator 15. Therefore, by allowing the refrigerant passing through the heat exchange section 200 via the bypass path to flow into the accumulator 15, it becomes possible to homogenize the refrigerant in the accumulator 15 when the refrigerant that has flowed through the bypass path agitates it. This prevents liquid refrigerant from flowing out of the accumulator 15 and suppresses the occurrence of liquid compression in the compressor 11.

[0048] Although the present invention has been described above with reference to preferred embodiments, it goes without saying that the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the present invention. [Explanation of Symbols]

[0049] 1: Vehicle air conditioning system 10: Refrigerant Circuit 11: Compressor 12: Indoor capacitor 13a, 13b, 13c, 13d: Pressure reducing device 14: Low temperature side heat exchanger 15: Accumulator 16: Evaporator 17:Outdoor heat exchanger 40: Battery temperature control circuit 41: Battery P40: Circulation pump 100: HVAC Unit 110: Case 120: Airflow channel 121: Heater core passage 122: Bypass passage 140: Blower 150: Air Mix Damper

Claims

1. The refrigerant circuit comprises a compressor, a condenser, a pressure reducing device, an evaporator, and a bypass path through which a portion of the refrigerant discharged by the compressor bypasses the condenser and flows to the upstream side of the compressor. In a vehicle air conditioning system capable of performing hot gas heating operation in which a portion of the refrigerant discharged by the compressor is flowed through the bypass path and the remaining refrigerant is flowed to the condenser, The system includes a heat exchange unit that, when hot gas heating is being performed, exchanges heat between the refrigerant flowing through the downstream path of the condenser and the refrigerant flowing through the downstream path of the pressure reducing device located on the bypass path. A vehicle air conditioning system characterized by the following features.

2. An accumulator is placed on the path downstream of the evaporator and upstream of the compressor. The bypass path includes a route through which the refrigerant discharged by the compressor bypasses the condenser, passes through the pressure reducing device, and flows downstream of the evaporator and upstream of the accumulator. The heat exchange unit exchanges heat between the refrigerant flowing through the downstream path of the condenser and the refrigerant flowing through the downstream path of the pressure reducing device located on the bypass path and upstream of the accumulator. The vehicle air conditioning system according to feature 1.

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