Vehicular air conditioning system

Abstract

To provide a vehicular air conditioning system that can efficiently dry a cooling evaporator.SOLUTION: A vehicular air conditioning system 1 includes: a refrigerant flow passage 52 capable of cooling a cabin by circulating a refrigerant through a compressor 10, an expansion valve 59 and a cooling evaporator 11 in this order; and a switching valve 55 capable of switching between a forward direction in which the refrigerant circulates to cool the cabin and an evaporator heating direction B in which the refrigerant circulates in the opposite direction to the forward direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to vehicle air conditioning systems. [Background technology]

[0002] 2. Description of the Related Art Vehicle air conditioning systems have been used to cool and heat a vehicle cabin. Technologies relating to such vehicle air conditioning systems are disclosed in, for example, Patent Documents 1 and 2, the sources of which are shown below.

[0003] Patent Document 1 describes a refrigeration cycle device. This refrigeration cycle device is applied to a vehicle air conditioner. The vehicle air conditioner is configured to be switchable between a cooling mode and a heating mode. In the cooling mode, the blown air is cooled by a cooling evaporator (called an interior evaporator in the document) and cold air is supplied to the interior of the vehicle. On the other hand, in the heating mode, heat is exchanged between the refrigerant that has been brought to a high-temperature and high-pressure state by the compressor and the heat-exchanged cooling water via a heater core, and the blown air is heated and warm air is supplied to the interior of the vehicle.

[0004] Patent Document 2 describes an air conditioner. This air conditioner is applied to an air conditioner for vehicles. The air conditioner is configured to be switchable between a dehumidifying and cooling mode and a cooling evaporator (called an evaporator in the document) heating mode. In the dehumidifying and cooling mode, the evaporator cools the blown air using the heat of evaporation of the refrigerant that has been cooled through the condenser and the expansion valve, and supplies cool air to the interior of the vehicle. On the other hand, in the evaporator heating mode, the refrigerant that has been brought to a high-temperature and high-pressure state by the compressor is circulated through a bypass path, and the high-temperature refrigerant that has been brought to a low pressure by the expansion valve is used to dry and remove condensation water that has adhered to the evaporator. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-60580 A [Patent Document 2] JP 2004-324983 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the refrigeration cycle device described in Patent Document 1, it is not possible to dry and remove the condensed water adhering to the cooling evaporator. In the air conditioner described in Patent Document 2, a bypass route is used, which makes the flow path configuration complicated and leads to an increase in the size of the air conditioner. In addition, an expansion valve is placed in the bypass route, which reduces the thermal energy of the refrigerant and takes time to dry the cooling evaporator.

[0007] Therefore, there is a demand for a vehicle air conditioning system that can efficiently dry the cooling evaporator. [Means for solving the problem]

[0008] The characteristic configuration of the vehicle air conditioning system of the present invention is that it is equipped with a refrigerant flow path that can circulate refrigerant through a compressor, an expansion valve, and an air-conditioning evaporator in that order to cool the vehicle cabin, and a switching valve that can switch between a forward direction in which the refrigerant circulates to cool the vehicle cabin, and an evaporator heating direction in which the refrigerant circulates in the opposite direction to the forward direction.

[0009] In this configuration, a switching valve is provided that can switch between a forward direction for cooling the passenger compartment and an evaporator heating direction for circulating the refrigerant in the opposite direction to the forward direction. Therefore, there is no need to provide a separate bypass flow path, and it is sufficient to simply provide a switching valve, simplifying the flow path configuration. In addition, in the evaporator heating direction, the compressor is directly connected to the cooling evaporator, so the thermal energy of the high-temperature, high-pressure refrigerant can be used to heat the cooling evaporator, significantly shortening the drying time of the cooling evaporator.

[0010] In this manner, the vehicle air conditioning system is capable of efficiently drying the cooling evaporator. [Brief description of the drawings]

[0011] [Figure 1]FIG. 1 is a circuit configuration diagram of a vehicle air conditioning system according to a first embodiment, illustrating a flow of refrigerant during heating of the interior of a vehicle. [Diagram 2] FIG. 1 is a circuit configuration diagram of a vehicle air conditioning system according to a first embodiment, illustrating the flow of refrigerant during cooling of the interior of a vehicle. [Diagram 3] FIG. 1 is a circuit configuration diagram of a vehicle air conditioning system according to a first embodiment, illustrating a flow of refrigerant when an evaporator is heated. [Figure 4] FIG. 11 is a circuit configuration diagram of a vehicle air conditioning system according to a second embodiment, illustrating the flow of refrigerant during heating of the interior of the vehicle. [Diagram 5] FIG. 11 is a circuit configuration diagram of a vehicle air conditioning system according to a second embodiment, illustrating the flow of refrigerant during cooling of the interior of the vehicle. [Figure 6] FIG. 11 is a circuit configuration diagram of a vehicle air conditioning system according to a second embodiment, illustrating the flow of refrigerant when an evaporator is heated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a vehicle air conditioning system according to the present invention will be described in detail with reference to the drawings. Note that the embodiments described below are merely examples for explaining the present invention, and the present invention is not limited to these embodiments. Therefore, the present invention can be embodied in various forms without departing from the gist of the present invention.

[0013] [First embodiment] FIG. 1 is a diagram showing a circuit configuration of a vehicle air conditioning system 1. The vehicle air conditioning system 1 is mounted on a vehicle, and has a refrigerant flow path 52 as shown in FIG. 1. A chiller 6 is disposed in the refrigerant flow path 52, and a cooling flow path (not shown) is connected to the chiller 6. A refrigerant such as hydrofluorocarbon (HFC) or hydrofluoroolefin (HFO) flows through the refrigerant flow path 52. A cooling liquid such as an antifreeze containing ethylene glycol as a main component, a long-life coolant, or an insulating oil such as paraffin-based oil flows through the cooling flow path. The vehicle air conditioning system 1 includes an evaporator 11 (evaporator for cooling) for cooling the interior of the vehicle, and an interior condenser 8 for heating the interior of the vehicle.

[0014] The refrigerant flow path 52 will be described. A refrigerant flows through the refrigerant flow path 52. The refrigerant flow path 52 has a refrigerant passage 521 on the downstream side of the flow direction of the refrigerant with respect to the chiller 6 (hereinafter, the upstream side and downstream side with respect to the flow direction of the refrigerant in the refrigerant flow path 52 are also simply referred to as the upstream side and downstream side). An accumulator 9, a compressor 10 (an example of a compressor), a first valve 15, and an indoor condenser 8 are arranged in this order in the middle of the refrigerant passage 521. The refrigerant passage 521 is connected to refrigerant passages 522 and 523 on the downstream side of the indoor condenser 8. The refrigerant passage 523 is connected to the chiller 6 via a first expansion valve 58 arranged in the middle. That is, the chiller 6 is attached to the refrigerant passage 523 at a position downstream with respect to the flow direction of the refrigerant compressed at high temperature by the compressor 10.

[0015] In the refrigerant flow path 52, a refrigerant path 524 is provided between the evaporator 11 and a switching valve 55, and a refrigerant path 525 is provided between the switching valve 55 and a portion of the refrigerant path 521 upstream of the accumulator 9.

[0016] A refrigerant path 526 branches off from the refrigerant path 521 downstream of the compressor 10 and upstream of the first valve 15. A second valve 16 and an exterior condenser 14 (an example of a heat exchanger) are arranged in this order in the middle of the refrigerant path 526. That is, in the vehicle air-conditioning system 1, the exterior condenser 14 that exchanges heat between the outside air and the refrigerant is provided between the compressor 10 and the second expansion valve 59 in the refrigerant flow path 52, and the refrigerant path 526 is connected to the refrigerant path 523 or the refrigerant path 527 on the downstream side.

[0017] A refrigerant path 527 branches off from the refrigerant path 523 on the upstream side of the first expansion valve 58 in the refrigerant path 523. The refrigerant path 527 is connected to the evaporator 11 on the downstream side.

[0018] Coolant path 521 is configured to be connectable to coolant paths 522, 526 or coolant path 525 via switching valve 55. Switching valve 55 is a four-way valve, and includes, for example, two L-shaped passages that are not connected to each other. Switching valve 55 is configured to be switchable between a first state (see FIGS. 1 and 2) in which coolant path 521 communicates with coolant paths 522, 526 and coolant path 524 communicates with coolant path 525, and a second state (see FIG. 3) in which coolant path 521 communicates with coolant path 524 and coolant path 525 communicates with coolant path 526.

[0019] Next, the flow of the refrigerant in the refrigerant passage 52 will be described. When the vehicle interior is heated, as shown in FIG. 1, the switching valve 55 is switched to the first state, and the refrigerant compressed by the compressor 10 to a high-temperature compressed gas flows from the refrigerant passage 521 to the refrigerant passage 522 by opening the first valve 15, and heats the air in the interior condenser 8. As a result, the heated air becomes hot air and is used to heat the vehicle interior. On the other hand, when the heating is not used, the first valve 15 is closed and the second valve 16 is opened. As a result, the refrigerant flows into the refrigerant passage 526 and is cooled by the exterior condenser 14. The refrigerant flowing out of the interior condenser 8 or the exterior condenser 14 flows through the refrigerant passage 523, is expanded by the first expansion valve 58, and is turned into a low-temperature, low-pressure mist, and is then sent to the chiller 6. The mist-like refrigerant absorbs heat from the cooling liquid flowing in from another passage (not shown) in the chiller 6 and evaporates. The refrigerant flowing out from chiller 6 flows through refrigerant passage 521, and if the vaporized refrigerant contains liquid, the liquid refrigerant is separated in accumulator 9. The vaporized refrigerant then flows out from accumulator 9 and returns to compressor 10, where it is compressed again to become a high-temperature, high-pressure gas.

[0020] On the other hand, when cooling the passenger compartment, as shown in FIG. 2, the switching valve 55 is kept switched to the first state, and the refrigerant compressed by the compressor 10 to a high-temperature compressed gas flows from the refrigerant passage 521 to the refrigerant passage 526 by opening the second valve 16, and dissipates heat to the outside air by the exterior condenser 14. The refrigerant flowing out from the exterior condenser 14 is expanded by the second expansion valve 59 in the refrigerant passage 527 to be turned into a low-temperature, low-pressure mist, and then flows into the evaporator 11. The refrigerant flowing into the evaporator 11 absorbs heat from the air introduced from the outside and evaporates. The air is cooled by the refrigerant absorbing heat, and is sent into the passenger compartment as cold air. The evaporated refrigerant flows through the refrigerant passage 524, the switching valve 55, and the refrigerant passage 525 into the refrigerant passage 521. The evaporated refrigerant flows through the refrigerant passage 521 to be sent to the accumulator 9. In the accumulator 9, if the vaporized refrigerant contains liquid, the liquid is separated from the vaporized refrigerant. The vaporized refrigerant then flows back to the compressor 10 and is compressed again to become a high-temperature compressed gas.

[0021] In the vehicle air conditioning system 1, condensed water may remain in the evaporator 11 after cooling is completed. Condensation in the evaporator 11 may cause mold and bacteria to grow, and may also cause an unpleasant odor in the evaporator 11. In the vehicle air conditioning system 1 of this embodiment, the refrigerant is circulated through the compressor 10, the second expansion valve 59, and the evaporator 11 in this order in the refrigerant flow path 52 to perform passenger compartment cooling, and the switching valve 55 is configured to be switchable between a forward direction A in which the refrigerant circulates to perform passenger compartment cooling, and an evaporator heating direction B in which the refrigerant circulates in the opposite direction to the forward direction A.

[0022] The first state (see Figure 2) of the switching valve 55, in which the refrigerant path 521 communicates with the refrigerant path 522, 526 and also communicates with the refrigerant path 524 and refrigerant path 525, corresponds to the forward direction A, and the second state (see Figure 3) of the switching valve 55, in which the refrigerant path 521 communicates with the refrigerant path 524 and also communicates with the refrigerant path 525 and refrigerant path 526, corresponds to the evaporator heating direction B.

[0023] The vehicle air conditioning system 1 is configured to switch the switching valve 55 from the cooling state shown in FIG. 2 to a second state as shown in FIG. 3 so that the refrigerant circulates in the evaporator heating direction B, whereby heat is absorbed from the outside air by the outdoor condenser 14, and then the refrigerant is pressurized by the compressor 10 and supplied to the evaporator 11, so that condensed water adhering to the evaporator 11 can be dried and removed.

[0024] As shown in FIG. 3, the switching valve 55 is switched to the second state, so that the refrigerant passage 521 and the refrigerant passage 524 communicate with each other. That is, the refrigerant is pressurized by the compressor 10 and then flows through the refrigerant passage 524. Here, since the refrigerant passage 524 is connected to the evaporator 11, the refrigerant flows into the evaporator 11. As a result, the evaporator 11 is heated by the high-temperature refrigerant pressurized by the compressor 10. The refrigerant that flows into the evaporator 11 flows through the refrigerant passage 527 and passes through the second expansion valve 59. At this time, the second expansion valve 59 is reversed to turn the refrigerant into a low-pressure mist. Thereafter, the refrigerant flows through the outdoor condenser 14 in the refrigerant passage 526. At this time, the outdoor condenser 14 exchanges heat with the outdoor air (heat absorption by the outdoor air), so that the refrigerant can be heated. Thereafter, the refrigerant passes through the switching valve 55 and the refrigerant path 525, merges with the refrigerant path 521, and flows back to the accumulator 9 and the compressor .

[0025] Thus, in the vehicle air conditioning system 1 of this embodiment, the refrigerant pressurized by the compressor 10 is directly introduced into the evaporator 11 to heat the evaporator 11. Furthermore, since the refrigerant that absorbs heat from the outside air in the exterior condenser 14 is circulated through the compressor 10, the thermal energy of the refrigerant that is returned to the compressor can be increased. As described above, the refrigerant circulation in the forward direction A shown in FIG. 2 (cooling state) is switched to the refrigerant circulation in the evaporator heating direction B shown in FIG. 3 when the cooling of the interior of the vehicle is stopped, and it is particularly preferable to do so immediately before stopping the vehicle. If it is immediately before stopping the vehicle, even if the evaporator 11 is heated and the temperature rises temporarily, the evaporator 11 will drop to an appropriate temperature while the vehicle is stopped. Therefore, the evaporator 11 can be operated without any problems in cooling the interior of the vehicle.

[0026] Second Embodiment In the above-described first embodiment, an example was shown in which the switching valve 55 is configured as a four-way valve. In the second embodiment, as shown in Fig. 4, the switching valve 55 is configured to have a plurality of on-off valves 55a to 55d. The other configurations are the same as those in the first embodiment.

[0027] In the second embodiment, as shown in Figs. 4 to 6, a first on-off valve 55a is arranged in the refrigerant passage 521 between the downstream side of the compressor 10 and the upstream side of the second valve 16 of the outdoor condenser 14. A second on-off valve 55b is arranged in the refrigerant passage 525. The upstream side of the first on-off valve 55a in the refrigerant passage 521 and the upstream side of the second on-off valve 55b in the refrigerant passage 525 are connected by a refrigerant passage 528. The downstream side of the first on-off valve 55a in the refrigerant passage 521 and the downstream side of the second on-off valve 55b in the refrigerant passage 525 are connected by a refrigerant passage 529. A third on-off valve 55c is arranged in the refrigerant passage 528, and a fourth on-off valve 55d is arranged in the refrigerant passage 529.

[0028] Next, the flow of the refrigerant in the refrigerant flow path 52 of the second embodiment will be described. In Fig. 4, the first on-off valve 55a is set to an open state, and the second on-off valve 55b, the third on-off valve 55c, and the fourth on-off valve 55d are set to a closed state. In Fig. 5, the first on-off valve 55a and the second on-off valve 55b are set to an open state, and the third on-off valve 55c and the fourth on-off valve 55d are set to a closed state.

[0029] FIG. 4 shows the vehicle interior heating state, in which the refrigerant compressed by the compressor 10 to a high-temperature compressed gas flows from the refrigerant passage 521 to the refrigerant passage 522 via the first on-off valve 55a when the first valve 15 is open, and heats the air in the interior condenser 8. When the heated air becomes hot air and is used to heat the vehicle interior, the second valve 16 opens, and the refrigerant flows into the refrigerant passage 526 and is cooled in the exterior condenser 14. The refrigerant flowing out of the interior condenser 8 or the exterior condenser 14 flows through the refrigerant passage 523, is expanded by the first expansion valve 58 to become a low-temperature, low-pressure mist, and is then sent to the chiller 6. The mist refrigerant absorbs heat from the cooling liquid flowing in from another flow path in the chiller 6 and evaporates. The refrigerant flowing out of the chiller 6 flows through the refrigerant passage 521, and in the accumulator 9, if the vaporized refrigerant contains liquid, the liquid refrigerant is separated. The vaporized refrigerant then flows out of the accumulator 9 and returns to the compressor 10, where it is compressed again to become a high-temperature, high-pressure gas.

[0030] On the other hand, when cooling the vehicle interior, as shown in FIG. 5, the refrigerant compressed by the compressor 10 to a high-temperature compressed gas flows through the refrigerant passage 521 to the refrigerant passage 526 when the second valve 16 is open via the first on-off valve 55a, and dissipates heat to the outside air in the exterior condenser 14. The refrigerant flowing out from the exterior condenser 14 is expanded by the second expansion valve 59 of the refrigerant passage 527 to be turned into a low-temperature, low-pressure mist, and then flows into the evaporator 11. The refrigerant flowing into the evaporator 11 absorbs heat from the air introduced from the outside and evaporates. The air is cooled by the refrigerant absorbing heat, and is sent into the vehicle interior as cold air. The evaporated refrigerant flows through the refrigerant passage 524, the on-off valve 55b, and the refrigerant passage 525 into the refrigerant passage 521. The evaporated refrigerant flows through the refrigerant passage 521 to be sent to the accumulator 9. In the accumulator 9, if the vaporized refrigerant contains liquid, the liquid is separated from the vaporized refrigerant. The vaporized refrigerant then flows back to the compressor 10 and is compressed again to become a high-temperature compressed gas.

[0031] In this embodiment, too, the vehicle air conditioning system 1 is configured to switch the switching valve 55 from the cooling state shown in FIG. 5 to circulate the refrigerant in the evaporator heating direction B as shown in FIG. 6, so that heat is absorbed from the outside air by the outdoor condenser 14, and then the refrigerant is pressurized by the compressor 10 and supplied to the evaporator 11, so that condensation water adhering to the evaporator 11 can be dried and removed.

[0032] Specifically, as shown in FIG. 6, the switching valve 55 closes the first on-off valve 55a and the second on-off valve 55b and opens the third on-off valve 55c and the fourth on-off valve 55d so that the refrigerant passage 521 and the refrigerant passage 525 communicate with each other. In this way, the refrigerant flows through the refrigerant passage 521, is pressurized by the compressor 10, flows from the refrigerant passage 528 to the refrigerant passage 524, and flows into the evaporator 11. As a result, the evaporator 11 is heated by the high-temperature refrigerant pressurized by the compressor 10. The refrigerant that flows into the evaporator 11 flows through the refrigerant passage 527 and passes through the second expansion valve 59. Thereafter, the refrigerant flows through the outdoor condenser 14 in the refrigerant passage 526. At this time, the outdoor condenser 14 exchanges heat with the outdoor air (heat absorption by the outdoor air), so that the refrigerant can be heated. Thereafter, the refrigerant flows from the refrigerant path 528 to the refrigerant path 525, merges with the refrigerant path 521, and flows back to the accumulator 9 and the compressor 10.

[0033] Other embodiments (a) In the above embodiment, an example in which the switching valve 55 is configured by a four-way valve and an example in which the switching valve 55 is configured by a plurality of on-off valves 55a to 55d are shown. The above embodiment is merely an example, and the switching valve 55 may have another form as long as it can be switched between a forward direction (A) in which the refrigerant circulates to perform passenger compartment cooling and an evaporator heating direction (B) in which the refrigerant flows in the opposite direction to the forward direction (A). (b) In the above embodiment, the refrigerant flow path 52 may have a water-cooled condenser (one example of a heat exchanger). In the refrigerant flow path 52, the water-cooled condenser may be provided instead of the exterior condenser 14 or in addition to the exterior condenser 14. The water-cooled condenser exchanges heat between the refrigerant and the cooling liquid. Therefore, when the cooling liquid is at a high temperature, the water-cooled condenser exchanges heat to absorb heat from the cooling liquid into the refrigerant, so that the evaporator 11 can be heated more efficiently even if the load on the compressor 10 is reduced.

[0034] In the above-described embodiment, the following configurations are envisaged. (1) One embodiment of a vehicle air conditioning system (1) includes a refrigerant flow path (52) capable of circulating refrigerant through a compressor (10), an expansion valve (59), and an air-conditioning evaporator (11) in that order to cool the vehicle cabin, and a switching valve (55) that can switch between a forward direction (A) in which the refrigerant circulates to cool the vehicle cabin and an evaporator heating direction (B) in which the refrigerant circulates in the opposite direction to the forward direction (A).

[0035] In this configuration, a changeover valve (55) is provided that can switch between a forward direction (A) for cooling the passenger compartment and an evaporator heating direction (B) for circulating the refrigerant in the opposite direction to the forward direction (A). This eliminates the need to provide a separate bypass flow path, and only requires the use of the changeover valve (55), simplifying the flow path configuration. In addition, in the evaporator heating direction (B), the compressor (10) is directly connected to the cooling evaporator (11), so that the thermal energy of the high-temperature, high-pressure refrigerant can be used to heat the cooling evaporator (11), and the drying time of the cooling evaporator (11) can be significantly shortened. In this way, the vehicle air conditioning system (1) is capable of efficiently drying the cooling evaporator (11).

[0036] (2) In the vehicle air conditioning system (1) described in (1), a heat exchanger (14) for exchanging heat between outside air and a refrigerant is further provided between the compressor (10) and the expansion valve (59). In the evaporator heating direction (B), the refrigerant that has absorbed heat from the outside air in the heat exchanger (14) is circulated to the compressor (10).

[0037] In the present configuration, in the evaporator heating direction (B), the refrigerant that has absorbed heat from the outside air in the heat exchanger (14) is circulated through the compressor (10), whereby it is possible to increase the thermal energy of the refrigerant that is returned to the compressor (10), and it is possible to reduce the driving force of the compressor (10) and thus save on electricity consumption.

[0038] In the vehicle air conditioning system described in (3)(2), the switching valve (55) is a four-way valve disposed between the compressor (10) and the heat exchanger (14).

[0039] By disposing a four-way valve between the compressor (10) and the heat exchanger (14) as in this configuration, the flow path configuration can be simplified.

[0040] (4) In the vehicle air conditioning system (1) according to any one of (1) to (3), the switching valve (55) switches to the evaporator heating direction (B) when the cooling of the passenger compartment is stopped.

[0041] By switching to the evaporator heating direction (B) when the cooling of the passenger compartment is stopped as in this configuration, it is possible to dry the cooling evaporator (11) in a short time using the thermal energy of the high-temperature, high-pressure refrigerant, which is efficient. [Industrial Applicability]

[0042] The present invention can be used in a vehicle air conditioning system. [Explanation of symbols]

[0043] 1: vehicle air conditioning system, 10: compressor, 11: evaporator, 14: outdoor condenser, 52: refrigerant flow path, 55: switching valve, 59: second expansion valve, A: forward direction, B: evaporator heating direction

Claims

1. a refrigerant flow path capable of circulating a refrigerant through a compressor, an expansion valve, and a cooling evaporator in this order to perform cooling of a vehicle interior; a switching valve that can switch between a forward direction in which the refrigerant circulates to perform the cooling of the passenger compartment and an evaporator heating direction in which the refrigerant circulates in a direction opposite to the forward direction.

2. a heat exchanger for exchanging heat between outside air and the refrigerant is further provided between the compressor and the expansion valve, The vehicle air conditioning system according to claim 1 , wherein in the evaporator heating direction, the refrigerant that has absorbed heat from the outside air in the heat exchanger is circulated through the compressor.

3. 3. The vehicle air conditioning system according to claim 2, wherein the switching valve is a four-way valve disposed between the compressor and the heat exchanger.

4. 4. The vehicle air conditioning system according to claim 1, wherein the switching valve switches the direction of the evaporator heating when cooling of the passenger compartment is stopped.

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