Air conditioner for vehicle

Abstract

[Problem] To provide an air conditioner for a vehicle capable of efficiently air-conditioning a vehicle interior while maintaining comfort in a cabin without clouding a window glass of the vehicle. [Solution] This air conditioner for a vehicle comprises an HVAC 10 provided with an interior blower 34 for circulating air inside and a temperature control part 20, an outside air passage 32 which is configured in the HVAC 10 and through which introduced outside air flows, a ventilation passage 37 that is configured in the HVAC 10 and that discharges drawn-in air to the outside of the cabin as ventilation, a desiccant rotor 41 disposed across the outside air passage 32 and the ventilation passage 37, and a control device for controlling the rotation of the desiccant rotor 41. The control device changes the rotation speed of the desiccant rotor 41.

Description

Vehicle air conditioning system

[0001] The present invention relates to a vehicle air conditioning device that conditions the interior of a vehicle.

[0002] Conventionally, vehicle air conditioning systems have been designed to provide air conditioning by discharging air cooled and heated by a temperature control unit, for example, a radiator or a heat sink, into the vehicle cabin through an HVAC system where outside air is drawn in from outside the vehicle cabin and inside air is drawn in from inside the vehicle cabin. In this case, the HVAC system is provided with an outside air passage through which outside air flows and a ventilation passage through which the drawn inside air is discharged as ventilation. Some systems have been designed to improve air conditioning efficiency by disposing a total heat exchanger at the intersection of these passages (see, for example, Patent Document 1).

[0003] That is, in Patent Document 1, the outside air introduced into the vehicle cabin via the HVAC and the portion of the inside air drawn into the HVAC that is discharged outside the vehicle cabin, i.e., the latent heat (humidity) and sensible heat (temperature) of the ventilation, are heat exchanged in a total heat exchanger, so that in summer, high-temperature, high-humidity outside air is heat exchanged with low-temperature, low-humidity ventilation air, making the outside air lower in temperature and humidity.In addition, in winter, low-temperature, low-humidity outside air is heated and humidified by high-temperature, high-humidity ventilation and supplied to the vehicle cabin, thereby reducing the heating and cooling load.

[0004] JP 57-138413 A JP 2016-70577 A JP 2019-82308 A

[0005] However, while this is not a problem in the summer, a problem occurs in the winter for a vehicle air conditioning system. The reason for this will be explained using the psychrometric chart in FIG. 11. In FIG. 11, the vertical axis represents absolute humidity, the horizontal axis represents temperature (dry-bulb temperature), and the curve represents relative humidity. Point Pa in the diagram represents the temperature and humidity of outside air in winter, and point Pr represents the temperature and humidity (stable air conditioning state) of ventilation (inside air discharged from the vehicle cabin) in winter. In this example, the temperature of the outside air (Pa) is +5°C, the absolute humidity is 0.003 kg / kg, and the relative humidity is 50%, while the temperature of the ventilation (Pr) is 25°C, the absolute humidity is 0.006 kg / kg, and the relative humidity is 30%. In other words, this is the case when the relative humidity of the outside air is higher than the relative humidity of the ventilation (inside air).

[0006] If total heat exchange between outside air and ventilation is performed in this state, the outside air will be humidified and the absolute humidity will increase, as shown by the thin solid arrow in the figure, causing the vehicle's windows (especially the windshield) to fog up, making it dangerous to drive. Also, if inside air is recirculated in winter, the window glass will fog up due to the breath of passengers, so the outside air intake rate must be increased, increasing the air conditioning load.

[0007] Meanwhile, residential air conditioning systems have also been developed that use a desiccant rotor to exchange heat between outside air and ventilation (see, for example, Patent Documents 2 and 3). In this case, Patent Document 2 allows switching between a total heat exchange function and a desiccant function by changing the rotation speed of the desiccant rotor. That is, the total heat exchange function is achieved by setting the rotation speed of the desiccant rotor to a predetermined high rotation speed (e.g., 480 rph to 1200 rph), and the desiccant function is achieved by setting the rotation speed to a predetermined low rotation speed (e.g., 2 rph to 20 rph). Furthermore, Patent Document 3 involves complex operations such as switching the refrigerant flow path in addition to switching the rotation speed of the desiccant rotor.

[0008] However, when this system is used in a vehicle air conditioner, if the rotation speed of the desiccant rotor is set to a high speed in winter to perform the total heat exchange function, the outside air will be humidified / heated by the inside air, causing the humidity inside the vehicle cabin to rise too much, resulting in the window glass fogging up just as in the case of the total heat exchanger described above. However, this does not pose a particular safety problem in a home.

[0009] Furthermore, if the desiccant rotor is set to a low rotation speed in winter to perform the desiccant function, and the absolute humidity of the outside air is lower than the absolute humidity of the ventilation (inside air) and the relative humidity of the outside air is higher than the relative humidity of the ventilation (inside air), the outside air, which has a high relative humidity, will be heated by the heat generated when it adsorbs moisture, but the absolute humidity of the outside air will decrease as shown by the dashed arrow in Figure 11 (the temperature will rise and the relative humidity will also decrease), causing the humidity inside the vehicle cabin to drop too much, resulting in a problem of discomfort for the passengers.

[0010] The present invention has been made to solve the above-mentioned conventional technical problems, and aims to provide a vehicle air conditioning device that can achieve efficient vehicle interior air conditioning without fogging up the vehicle's windows and maintaining comfort inside the vehicle.

[0011] The vehicle air conditioning system of the present invention comprises an HVAC equipped with a blower and a temperature control unit for circulating air inside, an outside air passage configured within the HVAC through which outside air introduced into the HVAC circulates, a ventilation passage configured within the HVAC through which the inside air drawn into the HVAC is discharged to the outside of the vehicle cabin as ventilation, a desiccant rotor arranged across the outside air passage and the ventilation passage, and a control device for controlling the rotation of the desiccant rotor, wherein the control device is characterized by changing the rotation speed of the desiccant rotor.

[0012] The vehicle air conditioning system of the present invention is characterized in that in the above invention, the control device adjusts the rotation speed of the desiccant rotor in a direction to increase the humidity inside the vehicle cabin within a range in which the vehicle window glass does not fog up.

[0013] The vehicle air conditioning system of the invention of claim 3 is characterized in that in the invention of claim 1, the control device rotates the desiccant rotor at a predetermined high rotation speed to achieve a total heat exchange function, and rotates the desiccant rotor at a predetermined medium rotation speed that is lower than the high rotation speed and higher than the predetermined low rotation speed at which the desiccant rotor achieves the desiccant function to achieve an intermediate function.

[0014] The vehicle air conditioning system of the invention of claim 4 is characterized in that in the above invention, the control device adjusts the rotation speed of the desiccant rotor based on the surface temperature of the vehicle window glass and the dew point temperature of the air near the window glass.

[0015] The vehicle air conditioning system of the invention of claim 5 is characterized in that in the above invention, the control device adjusts the rotation speed of the desiccant rotor in a direction to increase the humidity inside the vehicle cabin within a range in which the dew point temperature of the air near the window glass does not exceed a predetermined threshold value set based on the surface temperature of the window glass.

[0016] The vehicle air conditioning system of the invention of claim 6 is characterized in that in the above invention, the control device increases the rotation speed of the desiccant rotor when the dew point temperature of the air near the window glass is lower than a threshold value, and decreases the rotation speed of the desiccant rotor when the dew point temperature of the air near the window glass is higher than the threshold value.

[0017] The vehicle air conditioning system of the invention of claim 7 is characterized in that in the invention of claim 3, the control device sets the rotation speed of the desiccant rotor to a medium rotation speed and puts the desiccant rotor into an intermediate function when the absolute humidity of the outside air is lower than the absolute humidity of the inside air and the relative humidity of the outside air is higher than the relative humidity of the inside air.

[0018] The vehicle air conditioning system of the invention of claim 8 is characterized in that in the above invention, when the absolute humidity of the outside air is higher than the absolute humidity of the inside air, the control device sets the rotation speed of the desiccant rotor to a high rotation speed and gives the desiccant rotor a total heat exchange function.

[0019] The vehicle air conditioning system of the invention of claim 9 is characterized in that in each of the above inventions, the desiccant rotor is arranged downstream of the blower and upstream of the temperature adjustment unit in the flow of air circulating within the HVAC.

[0020] The vehicle air conditioning system of the invention of claim 10 is characterized in that in the above invention, the temperature adjustment unit is provided with a radiator for dissipating heat from the refrigerant to heat the air circulating within the HVAC, and a heat absorber for absorbing heat from the refrigerant to cool the air circulating within the HVAC.

[0021] The vehicle air conditioning system of the invention of claim 11 is characterized in that it comprises a bypass passage that returns the inside air sucked into the HVAC, bypassing the ventilation passage, to the passenger compartment, and a flow rate adjusting device that adjusts the flow rate of the air flowing through the ventilation passage and the air flowing through the bypass passage, in the inventions of claims 1 to 8.

[0022] The vehicle air conditioning system of the invention of claim 12 is characterized in that, in the above invention, it has a DEF outlet that blows air from the HVAC onto the vehicle window glass, and the bypass passage is located inside the HVAC on the opposite side of the DEF outlet.

[0023] The vehicle air conditioning system of the present invention comprises an HVAC equipped with a blower and a temperature adjustment unit for circulating air inside the HVAC, an outside air passage configured within the HVAC and through which outside air introduced into the HVAC circulates, a ventilation passage configured within the HVAC and through which inside air drawn into the HVAC is discharged to the outside of the vehicle cabin as ventilation, a desiccant rotor arranged across the outside air passage and the ventilation passage, and a control device for controlling the rotation of the desiccant rotor, and the control device is adapted to change the rotation speed of the desiccant rotor. Therefore, for example, as in the invention of claim 2, by using the control device to adjust the rotation speed of the desiccant rotor in a direction that increases the humidity inside the vehicle cabin within a range that does not cause the vehicle windows to fog up, it is possible to achieve efficient vehicle interior air conditioning while preventing the vehicle windows from fogging up and improving the comfort of passengers inside the vehicle without using complicated operations.

[0024] In this case, as in the invention of claim 3, the control device rotates the desiccant rotor at a predetermined high rotation speed to perform the total heat exchange function, and rotates the desiccant rotor at a predetermined medium rotation speed that is lower than the high rotation speed and higher than the predetermined low rotation speed at which the desiccant rotor performs the desiccant function to perform the intermediate function.By using the intermediate function of the desiccant rotor for sensible heat exchange, it is possible to exchange heat between the outside air and ventilation while suppressing a decrease in absolute humidity inside the vehicle cabin.

[0025] Specifically, for example, in winter, the control device adjusts the rotation speed of the desiccant rotor based on the surface temperature of the window glass of the vehicle and the dew point temperature of the air near the window glass.

[0026] According to the fifth aspect of the present invention, the rotation speed of the desiccant rotor is adjusted to increase the humidity inside the vehicle cabin within a range in which the dew point temperature of the air near the window glass does not exceed a predetermined threshold value set based on the surface temperature of the window glass. This makes it possible to achieve efficient air conditioning inside the vehicle cabin without fogging up the window glass, while maintaining high humidity inside the vehicle cabin and maintaining comfort.

[0027] This can be achieved by, for example, increasing the rotation speed of the desiccant rotor when the dew point temperature of the air near the window glass is lower than a threshold value, and decreasing the rotation speed of the desiccant rotor when the dew point temperature of the air near the window glass is higher than the threshold value, as in the invention of claim 6.

[0028] Furthermore, for example, in winter when the absolute humidity of the outside air is lower than the absolute humidity of the inside air and the relative humidity of the outside air is higher than the relative humidity of the inside air, the control device may rotate the desiccant rotor at a medium rotation speed, as in the invention of claim 7, so that the desiccant rotor performs an intermediate function. This makes it possible to defog the vehicle windows and improve the comfort of the vehicle interior by comparing the temperature and humidity of the outside and inside air without using complicated operations.

[0029] In this case, for example, in summer when the absolute humidity of the outside air is higher than that of the inside air, the rotation speed of the desiccant rotor is set to a high speed to set the total heat exchange function, as in the invention of claim 8. This allows switching between the total heat exchange function and the intermediate function according to environmental changes between the outside air and the inside air, making it possible to perform optimal operation in terms of air conditioning efficiency and comfort throughout the seasons.

[0030] Furthermore, as in the invention of claim 9, by arranging the desiccant rotor downstream of the blower and upstream of the temperature adjustment unit in the flow of air circulating within the HVAC, it becomes possible to circulate air before its temperature is adjusted by the temperature adjustment unit through the desiccant rotor, making it possible to properly exchange heat between outside air and ventilation in the desiccant rotor.

[0031] In this case, the temperature control unit is composed of a radiator for dissipating heat from the refrigerant to heat the air circulating inside the HVAC, and a heat sink for absorbing heat from the refrigerant to cool the air circulating inside the HVAC, as in the invention of claim 10, for example.

[0032] Furthermore, as in the invention of claim 11, by providing a bypass passage that bypasses the ventilation passage and returns the inside air sucked into the HVAC to the inside of the vehicle cabin, and a flow control device that adjusts the flow rate of the air flowing through the ventilation passage and the air flowing through the bypass passage, it is possible to circulate a ventilation volume that matches the amount of outside air introduced to the desiccant rotor with a simple operation.

[0033] In this case, by arranging the bypass passage inside the HVAC on the opposite side of the DEF outlet that blows air from the HVAC onto the vehicle window glass, as in the invention of claim 12, air with a lower dew point temperature can be blown out from the DEF outlet, thereby reliably and quickly preventing fogging of the window glass.

[0034] 1 is a schematic configuration diagram of an HVAC of a vehicle air conditioner according to an embodiment to which the present invention is applied (Example 1); FIG. 2 is a refrigerant circuit diagram of the vehicle air conditioner of FIG. 1; FIG. 3 is a block diagram of a control device of the vehicle air conditioner of FIG. 1; FIG. 4 is a flowchart illustrating an example of desiccant rotor control executed by the control device of FIG. 3; FIG. 5 is a diagram illustrating an example of a case where the desiccant rotor is set to a total heat exchange function in a cooling mode of the vehicle air conditioner of FIG. 1; FIG. 6 is a diagram illustrating an example of a case where the desiccant rotor is set to a total heat exchange function in a heating mode of the vehicle air conditioner of FIG. 1; FIG. 7 is a diagram illustrating an example of a case where the desiccant rotor is set to an intermediate function in a heating mode of the vehicle air conditioner of FIG. 1; FIG. 8 is a diagram illustrating an example of a case where the desiccant rotor is set to a desiccant function in a heating mode of the vehicle air conditioner of FIG. 1; FIG. 9 is a schematic configuration diagram of an HVAC of a vehicle air conditioner according to another embodiment of the present invention (Example 3); FIG. 10 is a schematic configuration diagram of an HVAC of a vehicle air conditioner according to yet another embodiment of the present invention (Example 4); FIG. 11 is a psychrometric chart of outside air and ventilation (inside air) of a vehicle.

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0036] The vehicle air conditioning system 1 of the embodiment is for an electric vehicle that cannot use engine waste heat for heating, and performs heating mode by operating a heat pump using a refrigerant circuit, and further selectively executes each of the operation modes of dehumidifying heating mode, dehumidifying cooling mode, cooling mode, and ventilation mode. Note that the vehicle is not limited to electric vehicles, but the present invention is also effective for so-called hybrid vehicles that use both an engine and an electric motor for driving, and it goes without saying that it can also be applied to ordinary vehicles that run on an engine.

[0037] First, the HVAC 10 in FIG. 1 and the refrigerant circuit R in FIG. 2 will be described. The vehicle air conditioning system 1 of the embodiment performs air conditioning (heating, cooling, dehumidification, and ventilation) for the interior of an electric vehicle, and includes an electric compressor 2 that compresses a refrigerant, a radiator 4 that is provided in an air flow passage 3 of an HVAC 10 through which interior air is circulated and into which high-temperature, high-pressure refrigerant discharged from the compressor 2 flows via a refrigerant pipe 13G and radiates heat from the refrigerant into the interior of the vehicle, an outdoor expansion valve 6 that is a motor-operated valve that reduces the pressure and expands the refrigerant during heating, an outdoor heat exchanger 7 that functions as a radiator during cooling and as an evaporator during heating and that exchanges heat between the refrigerant and the outside air, an indoor expansion valve 8 that is a motor-operated valve that reduces the pressure and expands the refrigerant, a heat absorber 9 that is provided in the air flow passage 3 and causes the refrigerant to absorb heat from inside and outside the vehicle during cooling and dehumidification, an evaporation pressure control valve 25 that adjusts the evaporation pressure in the heat absorber 9, an accumulator 12, and the like, all of which are connected in sequence by a refrigerant pipe 13 to form a refrigerant circuit R. Of these, the radiator 4 and the heat absorber 9 constitute a temperature control unit 30 (FIG. 1) of the present invention. The outdoor heat exchanger 7 is provided with an outdoor blower 15.

[0038] The outdoor heat exchanger 7 has a receiver-drier section 14 and a subcooling section 16 in that order downstream of the refrigerant, and the refrigerant pipe 13A coming out of the outdoor heat exchanger 7 is connected to the receiver-drier section 14 via a solenoid valve 17 for cooling that is opened during cooling, and the outlet of the subcooling section 16 is connected to the indoor expansion valve 8 via a check valve 18. The check valve 18 has a forward direction on the indoor expansion valve 8 side.

[0039] Furthermore, the refrigerant pipe 13B between the check valve 18 and the indoor expansion valve 8 is provided in a heat exchange relationship with the refrigerant pipe 13C that exits the evaporation pressure control valve 25 located on the outlet side of the heat absorber 9, and these together form an internal heat exchanger 19. As a result, the refrigerant that flows into the indoor expansion valve 8 via the refrigerant pipe 13B is cooled (supercooled) by the low-temperature refrigerant that exits the heat absorber 9 and passes through the evaporation pressure control valve 25.

[0040] Furthermore, the refrigerant pipe 13A extending from the outdoor heat exchanger 7 branches, and this branched refrigerant pipe 13D is connected to the refrigerant pipe 13C downstream of the internal heat exchanger 19 via a heating solenoid valve 21 that is opened during heating. Furthermore, the refrigerant pipe 13E on the outlet side of the radiator 4 branches before the outdoor expansion valve 6, and this branched refrigerant pipe 13F is connected to the refrigerant pipe 13B downstream of the check valve 18 via a dehumidifying solenoid valve 22 that is opened during dehumidification. That is, the solenoid valve 22 is connected in parallel to the outdoor heat exchanger 7.

[0041] A bypass pipe 13J is connected in parallel to the outdoor expansion valve 6, and a bypass solenoid valve 20 is provided in this bypass pipe 13J, which is opened in the cooling mode to allow the refrigerant to flow bypassing the outdoor expansion valve 6. The pipes between the outdoor expansion valve 6 and the solenoid valve 20 and the outdoor heat exchanger 7 are designated as 13I.

[0042] Next, the HVAC 10 of the vehicle air conditioning system 1 of the embodiment will be described with reference to Figure 1. An outside air intake 26 for introducing outside air into the air flow passage 3 and an inside air intake 27 for drawing air from within the vehicle cabin, i.e., inside air, into the air flow passage 3 are formed on the upstream side of the air flow passage 3 of the HVAC 10. An outside air damper 28 is provided at the outside air intake 26 for adjusting the opening degree of the outside air intake 26 to control the amount of outside air introduced, and an inside air damper 29 is provided at the inside air intake 27 for adjusting the opening degree of the inside air intake 27 to control the amount of inside air drawn in.

[0043] In the figure, reference numeral 31 denotes a partition plate provided on the upstream side of the air flow passage 3, and this partition plate 31 divides the air flow passage 3 of the HVAC 10 on the upstream side into an outdoor air passage 32 and an indoor air passage 33, with the outdoor air intake port 26 communicating with the outdoor air passage 32 and the indoor air intake port 27 communicating with the indoor air passage 33. In the figure, reference numeral 34 denotes an indoor blower (a blower in the present invention) for circulating air through the air flow passage 3 of the HVAC 10. The indoor blower 34 is disposed across the outdoor air passage 32 and the indoor air passage 33, but its interior is divided into an outdoor air passage 32 side and an indoor air passage 33 side. As a result, when the indoor blower 34 is operated, outdoor air is introduced into the outdoor air passage 32 through the outdoor air intake port 26, and indoor air is sucked into the indoor air passage 33 through the indoor air intake port 27.

[0044] In the figure, reference numeral 36 denotes a total outside air damper provided at the boundary between the outside air passage 32 and the inside air passage 33 on the air upstream side of the indoor blower 34. When the inside air intake port 27 is closed by the inside air damper 29 and only outside air is introduced without sucking in inside air, this total outside air damper 36 is opened, connecting the outside air passage 32 and the inside air passage 33 so that outside air can be introduced into both of them.

[0045] In the drawing, reference numeral 37 denotes a ventilation passageway formed within the HVAC 10 and communicating with the inside air passageway 33, for discharging the inside air drawn into the inside air passageway 33 to the outside of the vehicle cabin as ventilation. Reference numeral 38 denotes a bypass passageway formed within the HVAC 10, for returning the inside air drawn into the HVAC 10 to the inside of the vehicle cabin, bypassing the ventilation passageway 37, and constituting part of the inside air passageway 33. Reference numeral 39 denotes a rotary ventilation damper serving as a flow rate adjusting device provided at the communicating portion between the inside air passageway 33 and the ventilation passageway 37, and this ventilation damper 39 adjusts the flow rate of air flowing through the ventilation passageway 37 and the bypass passageway 38.

[0046] In the figure, reference numeral 41 denotes a desiccant rotor. This desiccant rotor 41 is constructed by supporting a polymeric adsorbent on a substrate, forming it into a honeycomb shape, and shaping it into a rotor shape. This desiccant rotor 41 is driven to rotate by a desiccant rotor motor 42 (described later), and its rotation speed is controlled and changeable by a control device 11 (described later). The desiccant rotor 41 is disposed within the air flow passage 3 of the HVAC 10, straddling the outside air passage 32 and the ventilation passage 37, with the outside air passage 32 side being the treatment side and the ventilation passage 37 side being the regeneration side. The operation and control of this desiccant rotor 41 will be described in detail later.

[0047] In this embodiment, the outside air passage 32 and the bypass passage 38 (inside air passage 33) join (communicate) at a joining point 43 located downstream in the air direction from the desiccant rotor 41. The heat absorber 9 constituting the temperature adjustment unit 30 described above is provided in the air flow passage 3 downstream in the air direction from the joining point 43, and the radiator 4 also constituting the temperature adjustment unit 30 is provided downstream in the air direction from the heat absorber 9. That is, the desiccant rotor 41 is located downstream of the indoor blower 34 and upstream of the temperature adjustment unit 30 in the flow of air circulating inside the HVAC 10.

[0048] A heating passage and a bypass passage (not shown) are formed in the air flow passage 3, and the radiator 4 is provided in the heating passage. An air mix damper 44 is provided in the air flow passage 3 on the air upstream side of the radiator 4 to adjust the proportion of air (indoor air or outdoor air) that has passed through the heat absorber 9 and is ventilated into the heating passage.

[0049] Furthermore, the HVAC 10 on the downstream side of the radiator 4 is formed with a foot outlet 46, a vent outlet 47, and a defroster outlet 48. The foot outlet 46 is an outlet for blowing air to the feet inside the vehicle cabin and is located at the lowest position. The vent outlet 47 is an outlet for blowing air to the chest and face of passengers inside the vehicle cabin and is located above the foot outlet 46. The defroster outlet 48 is an outlet for blowing air to the inner surface of the vehicle window glass (windshield) and is located above the other outlets 46 and 47, making it the highest position in the HVAC 10.

[0050] The bypass passage 38 is located at the lowest position in the HVAC 10. That is, the bypass passage 38 in this embodiment is located inside the HVAC 10 on the opposite side from the DEF outlet 48.

[0051] The foot outlet 46, the vent outlet 47, and the defroster outlet 48 are provided with a foot outlet damper 51, a vent outlet damper 52, and a defroster outlet damper 53, respectively, which control the amount of air blown out. In this case, the defroster outlet damper 53 is configured to block air flowing toward the foot outlet 46 and the vent outlet 47, allowing air to be blown out only from the defroster outlet 48.

[0052] 3 is a block diagram showing the control device 11 of the vehicle air conditioning device 1 of the embodiment. The control device 11 is composed of a microcomputer, which is an example of a computer equipped with a processor. The inputs to the control device 11 include an outside air temperature sensor 54 that detects the temperature of outside air (outside air temperature) introduced through the outside air inlet 26, an outside air humidity sensor 56 that detects the humidity of outside air (outside air humidity), an inside air temperature sensor 57 that detects the temperature of inside air (air inside the vehicle cabin) drawn through the inside air inlet 27 (inside air temperature), an inside air humidity sensor 58 that detects the humidity of inside air (inside air humidity), a window glass surface temperature sensor 59 that detects the surface temperature of the vehicle's window glass, an air temperature sensor 61 near the window glass that detects the temperature of air near the window glass, an air humidity sensor 62 near the window glass that detects the humidity of air near the window glass, and refrigerant circuit temperature sensors that detect the temperatures of various parts of the refrigerant circuit R. Connected to the HVAC 10 are a refrigerant circuit pressure sensor 63 (which is actually provided in each part of the refrigerant circuit R, but is shown as one representative), a refrigerant circuit pressure sensor 64 (which is also actually provided in each part of the refrigerant circuit R, but is shown as one representative), a blown air temperature sensor 66 which detects the temperature of the air blown into the passenger compartment from the HVAC 10, an indoor CO2 concentration sensor 67 which detects the carbon dioxide concentration in the passenger compartment, a solar radiation sensor 68, for example a photosensor type, for detecting the amount of solar radiation entering the passenger compartment, and the outputs of a vehicle speed sensor 69 which detects the vehicle's moving speed (vehicle speed), and an air conditioning (air conditioner) operation unit 71 for setting the set temperature and switching the operating mode.

[0053] The output of the control device 11 is connected to the compressor 2, the outdoor blower 15, the indoor blower (blower) 34, the desiccant rotor motor 42, the solenoid valves 22, 21, 17, and 20, the outdoor expansion valve 6, the indoor expansion valve 8, the outdoor air damper 28, the indoor air damper 29, the ventilation damper 39, the total outdoor air damper 36, the air mix damper 44, the foot outlet damper 51, the vent outlet damper 52, and the desiccant outlet damper 53, all of which are controlled by the control device 11. In this case, the control device 11 adjusts the amount of air flowing into the ventilation passage 37 and the bypass passage 38 using the ventilation damper 39, thereby adjusting the amount of indoor air flowing to the junction 43 without passing through the desiccant rotor 41 and the amount of ventilation air passing through the desiccant rotor 41 and being discharged, and thereby circulating a ventilation amount that matches the amount of outdoor air introduced through the desiccant rotor 41.

[0054] The operation of the vehicle air conditioning system 1 of the embodiment configured as described above will now be described. In this embodiment, the control device 11 switches between the following operating modes: heating mode, dehumidifying heating mode, dehumidifying cooling mode, cooling mode, and ventilation mode. First, an overview of the refrigerant flow and control in each operating mode will be described. Note that in the ventilation mode, the refrigerant circuit R is stopped, so its description will be omitted.

[0055] (1) Heating Mode When the heating mode is selected by the control device 11 or manually by operating the air conditioning operation unit 71, the control device 11 opens the solenoid valve 21 and closes the solenoid valves 17, 22, and 20. Then, the compressor 2 and the blowers 15 and 34 are operated, and the air mix damper 44 brings the air blown out from the indoor blower 34 into the radiator 4 via the desiccant rotor 41. The operation and control of the desiccant rotor 41 will be described in detail later (the same applies hereinafter).

[0056] As a result, the high-temperature, high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4. As the air in the air flow passage 3 is passed through the radiator 4, the air in the air flow passage 3 is heated by the high-temperature refrigerant in the radiator 4, while the refrigerant in the radiator 4 is cooled by heat absorption by the air, condensing and liquefying. The refrigerant liquefied in the radiator 4 leaves the radiator 4 and travels through the refrigerant pipe 13E to the outdoor expansion valve 6. The refrigerant flowing into the outdoor expansion valve 6 is decompressed there and then flows into the outdoor heat exchanger 7. The refrigerant flowing into the outdoor heat exchanger 7 evaporates and draws heat from the outside air blown by the outdoor fan 15 or from the vehicle's movement. In other words, the refrigerant circuit R functions as a heat pump, and the outdoor heat exchanger 7 functions as a refrigerant evaporator.

[0057] The low-temperature refrigerant leaving the exterior heat exchanger 7 passes through the refrigerant pipe 13A, the solenoid valve 21, and the refrigerant pipe 13D, and then enters the accumulator 12 from the refrigerant pipe 13C, where it is separated into gas and liquid, and the gas refrigerant is then sucked into the compressor 2, repeating this cycle. The air heated by the radiator 4 is blown out from the air outlets 46 to 48, thereby heating the vehicle interior.

[0058] The control device 11 controls the rotation speed of the compressor 2 based on the high-pressure pressure of the refrigerant circuit R detected by the refrigerant circuit pressure sensor 64, and also controls the valve opening degree of the outdoor expansion valve 6 based on the temperature of the radiator 4 detected by the refrigerant circuit temperature sensor 63 and the refrigerant pressure of the radiator 4 detected by the refrigerant circuit pressure sensor 64, thereby controlling the degree of subcooling of the refrigerant at the outlet of the radiator 4.

[0059] (2) Dehumidifying and Heating Mode Next, in the dehumidifying and heating mode, the control device 11 opens the solenoid valve 22 in the heating mode. As a result, a portion of the condensed refrigerant flowing through the refrigerant pipe 13E via the radiator 4 is diverted and passes through the solenoid valve 22 to the refrigerant pipes 13F and 13B, then to the internal heat exchanger 19 and to the indoor expansion valve 8. After the refrigerant is decompressed by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. Due to the heat absorption effect at this time, moisture in the air blown out from the indoor blower 34 passes through the desiccant rotor 41 and condenses and adheres to the heat absorber 9, so the air is cooled and dehumidified.

[0060] The refrigerant evaporated in the heat absorber 9 passes through the evaporation pressure control valve 25 and the internal heat exchanger 19, merges with the refrigerant from the refrigerant pipe 13D in the refrigerant pipe 13C, and then repeats the circulation process of being drawn into the compressor 2 via the accumulator 12. The air dehumidified in the heat absorber 9 is reheated as it passes through the radiator 4, thereby dehumidifying and heating the vehicle cabin. The control device 11 controls the rotation speed of the compressor 2 based on the high-pressure pressure of the refrigerant circuit R detected by the refrigerant circuit pressure sensor 64, and also controls the valve opening of the outdoor expansion valve 6 based on the temperature of the heat absorber 9 detected by the refrigerant circuit temperature sensor 63.

[0061] (3) Dehumidifying Cooling Mode Next, in the dehumidifying cooling mode, the control device 11 opens the solenoid valve 17 and closes the solenoid valves 21, 22, and 20. Then, the compressor 2 and the blowers 15 and 34 are operated, and the air mix damper 44 is set in a state where the air blown from the indoor blower 34 is ventilated to the radiator 4. As a result, the high-temperature, high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4. Since the air in the air flow passage 3 is ventilated to the radiator 4, the air in the air flow passage 3 is heated by the high-temperature refrigerant in the radiator 4, while the refrigerant in the radiator 4 is cooled by the air absorbing heat, and is condensed and liquefied.

[0062] The refrigerant leaving the radiator 4 passes through refrigerant pipe 13E to the outdoor expansion valve 6, which is controlled to be slightly open, before flowing into the outdoor heat exchanger 7. The refrigerant that flows into the outdoor heat exchanger 7 is cooled and condensed there by the vehicle running or by outside air blown by the outdoor blower 15. The refrigerant leaving the outdoor heat exchanger 7 passes through refrigerant pipe 13A, solenoid valve 17, and flows successively into the receiver-drier unit 14 and subcooling unit 16, where the refrigerant is subcooled.

[0063] The refrigerant leaving the subcooling section 16 of the outdoor heat exchanger 7 passes through the check valve 18 and enters the refrigerant pipe 13B, then passes through the internal heat exchanger 19 and reaches the indoor expansion valve 8. After the refrigerant is decompressed by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. Due to the heat absorption effect at this time, moisture in the air blown out from the indoor blower 34 passes through the desiccant rotor 41 and condenses and adheres to the heat absorber 9, so the air is cooled and dehumidified.

[0064] The refrigerant evaporated in the heat absorber 9 passes through the evaporation pressure control valve 25, the internal heat exchanger 19, and the refrigerant pipe 13C to reach the accumulator 12, from which it is repeatedly circulated and drawn into the compressor 2. The air cooled and dehumidified in the heat absorber 9 is reheated (with a lower heat dissipation capacity than during heating) as it passes through the radiator 4, thereby performing dehumidifying and cooling of the vehicle cabin. The control device 11 controls the rotation speed of the compressor 2 based on the temperature of the heat absorber 9 detected by the refrigerant circuit temperature sensor 63, and also controls the valve opening of the outdoor expansion valve 6 based on the high-pressure pressure of the refrigerant circuit R described above, thereby controlling the refrigerant pressure in the radiator 4.

[0065] (4) Cooling Mode Next, in the cooling mode, the control device 11 opens the solenoid valve 20 in the dehumidifying and cooling mode (in this case, the outdoor expansion valve 6 may be at any valve opening, including fully open (the valve opening is at the upper limit of the control limit)), and the air mix damper 44 is in a state where it controls the ventilation amount, including a state where air is not ventilated to the radiator 4. As a result, the high-temperature, high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4. When the air in the air flow passage 3 is not ventilated to the radiator 4, it simply passes through here, and when it is ventilated, heat is radiated to the air. The refrigerant that leaves the radiator 4 reaches the solenoid valve 20 and the outdoor expansion valve 6 through the refrigerant pipe 13E.

[0066] At this time, solenoid valve 20 is open, so the refrigerant bypasses outdoor expansion valve 6, passes through bypass pipe 13J, and flows directly into outdoor heat exchanger 7, where it is air-cooled by running or by outside air blown by outdoor blower 15, and condenses into a liquid. The refrigerant that leaves outdoor heat exchanger 7 flows from refrigerant pipe 13A, passes through solenoid valve 17, and sequentially flows into receiver-drier section 14 and subcooling section 16, where it is subcooled.

[0067] The refrigerant leaving the subcooling section 16 of the outdoor heat exchanger 7 passes through the check valve 18 and enters the refrigerant pipe 13B, then passes through the internal heat exchanger 19 and reaches the indoor expansion valve 8. After the refrigerant is decompressed by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. Due to the heat absorption effect at this time, moisture in the air that has been blown out from the indoor blower 34 and passed through the desiccant rotor 41 condenses and adheres to the heat absorber 9, so the air is cooled and dehumidified.

[0068] The refrigerant evaporated in the heat absorber 9 passes through the evaporation pressure control valve 25, the internal heat exchanger 19, and the refrigerant pipe 13C to reach the accumulator 12, from which it is repeatedly circulated and drawn into the compressor 2. The air cooled and dehumidified in the heat absorber 9 does not pass through the radiator 4 or passes only slightly therethrough, and is blown into the passenger compartment from the air outlets 46 to 48, thereby cooling the passenger compartment. In this cooling mode, the control device 11 controls the rotation speed of the compressor 2 based on the temperature of the heat absorber 9 detected by the refrigerant circuit temperature sensor 63.

[0069] At startup, the control device 11 selects an operation mode based on the inside air temperature and the target outlet temperature TAO. After startup, the control device 11 selects and switches between the operation modes in response to changes in the environment and setting conditions, such as the inside air temperature and the target outlet temperature TAO.

[0070] (5) Operation of the desiccant rotor 41 under the control of the control device 11 Next, the operation of the desiccant rotor 41 will be described with reference to Figures 5 to 8. As described above, the desiccant rotor 41 is disposed within the HVAC 10, straddling the outside air passage 32 and the ventilation passage 37. Therefore, outside air introduced into the HVAC 10 is ventilated on the outside air passage 32 side (treatment side), and ventilation air (inside air) discharged outside the vehicle cabin is ventilated on the ventilation passage 37 (regeneration side). This allows for the exchange of sensible heat (temperature) and latent heat (humidity) between the outside air and the ventilation air.

[0071] In this case, if the rotation speed of the desiccant rotor 41 is set to a predetermined high rotation speed (e.g., 480 rph to 1200 rph), the desiccant rotor 41 performs a total heat exchange function, enabling total heat exchange of both sensible heat and latent heat. On the other hand, if the rotation speed of the desiccant rotor 41 is set to a predetermined low rotation speed (e.g., 2 rph to 20 rph), the desiccant rotor 41 performs a desiccant function, enabling normal dehumidification. On the other hand, if the rotation speed is set to a medium rotation speed (e.g., 100 rph to 500 rph) that is lower than this high rotation speed but higher than the low rotation speed, it becomes possible to exchange only sensible heat, which raises the temperature without changing the absolute humidity of the outside air, as shown by the thick solid arrow in Figure 11. This is referred to as an intermediate function in the present invention.

[0072] In the present invention, as described above, the desiccant rotor motor 42 that rotates and drives the desiccant rotor 41 is controlled by the control device 11. The rotation speed of the desiccant rotor 41 is changed and controlled by the control device 11, so that the desiccant rotor 41 is configured to be able to perform a total heat exchange function, a desiccant function, or an intermediate function between them.

[0073] (5-1) Total heat exchange function in cooling mode (800 rph) Figure 5 is a diagram illustrating the changes in the flow rate, temperature, and relative humidity (RH) of the outside air and the inside air (ventilation) when the rotation speed of the desiccant rotor 41 is set to, for example, 800 rph (high rotation speed) in the cooling mode described above in summer, thereby achieving the total heat exchange function. That is, when the flow rate of the outside air introduced from the outside air inlet 26 is 102 m 3 / h, the temperature is +35°C, the relative humidity is 60%, and the flow rate of the inside air drawn in from the inside air intake 27 is 200 m 3 / h, the temperature is +25°C, the relative humidity is 30%, and the flow rate of the ventilation exhausted from the ventilation passage 37 is 102 m 3 / h, and the flow rate of the inside air flowing through the bypass passage 38 is 98 m 3 / h, the outside air is cooled and dehumidified by the desiccant rotor 41, so the temperature of the outside air that passes through the desiccant rotor 41 and reaches the junction 43 drops to +30.0°C and the relative humidity drops to 51.3%. On the other hand, the ventilation air is heated and humidified by the desiccant rotor 41, so the temperature of the ventilation air discharged through the desiccant rotor 41 rises to +29.9°C and the relative humidity rises to 50.1%.

[0074] The temperature of the air resulting from the merging of the outside air and the inside air at junction 43 is +27.5°C, the relative humidity is 42.6%, and the enthalpy is 52.61 kJ / kg. After being cooled by heat absorber 9 (assuming the efficiency of each heat exchanger is 50%), the air is blown out from vent outlet 47, at which point the temperature of the blown out air is +5°C, the relative humidity is 100%, and the enthalpy is 18.64 kJ / kg.

[0075] Here, if the desiccant rotor 41 is not used, the air temperature at the confluence 43 will be +30.0°C, the relative humidity will be 51.2%, and the enthalpy will be 65.04 kJ / kg. Therefore, comparing the case with and without the desiccant rotor 41, we find that 1 - (52.61 - 18.64) / (65.04 - 18.64) = 1 - 33.97 / 46.40 = 0.268, or 26.8% energy savings.

[0076] (5-2) Total heat exchange function in heating mode (800 rph) Next, Fig. 6 is a diagram illustrating the changes in the flow rate, temperature, and relative humidity (RH) of the outside air and the inside air (ventilation) when the rotation speed of the desiccant rotor 41 is set to 800 rph (high rotation speed) in the heating mode in winter, for example, to perform the total heat exchange function. That is, when the flow rate of the outside air introduced from the outside air inlet 26 is 102 m 3 / h, the temperature is +5°C, the relative humidity is 50%, and the flow rate of the inside air drawn in from the inside air intake 27 is 200 m 3 / h, the temperature is +25°C, the relative humidity is 30%, and the flow rate of the ventilation exhausted from the ventilation passage 37 is 102 m 3 / h, and the flow rate of the inside air flowing through the bypass passage 38 is 98 m 3 / h, the outside air is heated and humidified by the desiccant rotor 41, so the temperature of the outside air that passes through the desiccant rotor 41 and reaches the junction 43 rises to +14.3°C and the relative humidity falls to 41.4%. On the other hand, the ventilation air is cooled and dehumidified by the desiccant rotor 41, so the temperature of the ventilation air discharged through the desiccant rotor 41 falls to +15.0°C and the relative humidity rises to 40.7%.

[0077] The air resulting from the merging of the outside and inside air at junction 43 has a temperature of +19.4°C, a relative humidity of 35.8%, an enthalpy of 32.17 kJ / kg, and an absolute humidity (weight) of 0.005006 kg / kg. After being heated by radiator 4, this air is blown out from foot outlet 46, at which point the temperature of the blown-out air is +50.0°C, a relative humidity of 6.5%, an enthalpy of 63.27 kJ / kg, and a dew point temperature of +3.9°C.

[0078] Here, when the desiccant rotor 41 is not used, the air temperature at the confluence 43 is +14.4°C, the relative humidity is 41.3%, the enthalpy is 25.17 kJ / kg, and the absolute humidity (weight) is 0.004217 kg / kg; the absolute humidity is higher when the desiccant rotor 41 is used.

[0079] Furthermore, when the desiccant rotor 41 is not used, the temperature of the air blown out from the foot outlet 46 is +50°C, the relative humidity is 5.5%, the enthalpy is 61.23 kJ / kg, and the dew point temperature is +1.5°C. Therefore, when comparing the case with and without the desiccant rotor 41, 1 - (63.27 - 32.17) / (61.23 - 25.17) = 1 - 31.10 / 36.06 = 0.138, or 13.8% energy savings are achieved. However, as described above, when the desiccant rotor 41 is used, the dew point temperature rises from +1.5°C to +3.9°C compared to when the desiccant rotor 41 is not used, which means that the vehicle windows are more likely to fog up.

[0080] (5-3) Heating Mode at Intermediate Function (300 rph) Next, Fig. 7 is a diagram illustrating the changes in the flow rate, temperature, and relative humidity (RH) of the outside air and the inside air (ventilation) when the rotation speed of the desiccant rotor 41 is set to 300 rph (medium rotation speed) in the heating mode described above in winter, thereby setting the above-mentioned intermediate function. In this case, as in the case of Fig. 6, the flow rate of the outside air introduced from the outside air inlet 26 is 102 m 3 / h, the temperature is +5°C, the relative humidity is 50%, and the flow rate of the inside air drawn in from the inside air intake 27 is 200 m 3 / h, the temperature is +25°C, the relative humidity is 30%, and the flow rate of the ventilation air discharged from the ventilation passage 37 is 102 m 3 / h, and the flow rate of the inside air flowing through the bypass passage 38 is 98 m 3 / h.

[0081] In this case, the outside air is heated by the desiccant rotor 41 (the amount of heating is less than in Figure 6) and is not humidified or dehumidified (the amount of humidification is less than in Figure 6), so the temperature of the outside air that passes through the desiccant rotor 41 and reaches the junction 43 rises to +8.5°C and the relative humidity falls to 39.4%. On the other hand, the ventilation air is cooled by the desiccant rotor 41 and is not humidified or dehumidified, so the temperature of the ventilation air discharged through the desiccant rotor 41 falls slightly to +21.3°C and the relative humidity rises to 37.6%.

[0082] The temperature of the air resulting from the merging of the outside air and inside air at junction 43 is +16.3°C, the relative humidity is 36.8%, the enthalpy is 27.03 kJ / kg, and the absolute humidity (weight) is 0.004217 kg / kg. After being heated by radiator 4, this air is blown out from foot outlet 46, at which point the temperature of the blown out air is +50.0°C, the relative humidity is 5.5%, the enthalpy is 61.23 kJ / kg, and the dew point temperature is +1.5°C.

[0083] Here, when the desiccant rotor 41 is not used, the air temperature at the confluence 43 is +14.4°C, the relative humidity is 41.3%, the enthalpy is 25.17 kJ / kg, and the absolute humidity (weight) is 0.004217 kg / kg, just as in the case of FIG. 6, and it can be seen that the absolute humidity remains unchanged even when the desiccant rotor 41 is used.

[0084] Furthermore, when the desiccant rotor 41 is not used, the temperature of the air blown out from the foot outlet 46 is +50°C, the relative humidity is 5.5%, the enthalpy is 61.23 kJ / kg, and the dew point temperature is +1.5°C, just as in the case of Figure 6. Therefore, comparing the case with and without the desiccant rotor 41, 1 - (61.23 - 27.03) / (61.23 - 25.17) = 1 - 34.20 / 36.06 = 0.052, or 5.2% energy savings.

[0085] Furthermore, since the dew point temperature remains the same at +1.5°C whether the desiccant rotor 41 is used or not, it can be seen that under these conditions, by setting the desiccant rotor 41 to the intermediate function, the vehicle window glass does not become prone to fogging even when the desiccant rotor 41 is used. This is because the dew point temperature can be lowered by setting the desiccant rotor 41 to the intermediate function compared to the total heat exchange function.

[0086] (5-4) Desiccant function in heating mode (10 rph) Next, Fig. 8 is a diagram illustrating the changes in the flow rate, temperature, and relative humidity (RH) of the outside air and the inside air (ventilation) when the desiccant function is activated by setting the rotation speed of the desiccant rotor 41 to 10 rph (low rotation speed) in the heating mode in winter. In this case, as in Figs. 6 and 7, the flow rate of the outside air introduced from the outside air inlet 26 is 102 m 3 / h, the temperature is +5°C, the relative humidity is 50%, and the flow rate of the inside air drawn in from the inside air intake 27 is 200 m 3 / h, the temperature is +25°C, the relative humidity is 30%, and the flow rate of the ventilation air discharged from the ventilation passage 37 is 102 m 3 / h, and the flow rate of the inside air flowing through the bypass passage 38 is 98 m 3 / h.

[0087] In this case, the outside air is heated by the desiccant rotor 41 (even less heating than in FIG. 7) and dehumidified (more dehumidification than in FIG. 7), so the temperature of the outside air that passes through the desiccant rotor 41 and reaches the junction 43 rises to +6.0°C and the relative humidity falls to 39.4%. On the other hand, the ventilation air is cooled and humidified by the desiccant rotor 41, so the temperature of the ventilation air discharged through the desiccant rotor 41 falls slightly to +24.0°C and the relative humidity rises to 34.1%.

[0088] The air resulting from the merging of the outside and inside air at junction 43 has a temperature of +15.0°C, a relative humidity of 37.8%, an enthalpy of 25.17 kJ / kg, and an absolute humidity (weight) of 0.003996 kg / kg. After being heated by radiator 4, this air is blown out from foot outlet 46, at which point the temperature of the blown-out air is +50.0°C, a relative humidity of 5.2%, an enthalpy of 60.66 kJ / kg, and a dew point temperature of +0.8°C.

[0089] Here, when the desiccant rotor 41 is not used, the air temperature at the confluence 43 is +14.4°C, the relative humidity is 41.3%, the enthalpy is 25.17 kJ / kg, and the absolute humidity (weight) is 0.004217 kg / kg, just as in the cases of Figures 6 and 7. It can be seen that when the desiccant rotor 41 is used, the absolute humidity decreases, making the passengers feel uncomfortable.

[0090] Furthermore, when the desiccant rotor 41 is not used, the temperature of the air blown out from the foot outlet 46 is +50°C, the relative humidity is 5.5%, the enthalpy is 61.23 kJ / kg, and the dew point temperature is +1.5°C, just as in the cases of Figures 6 and 7. Therefore, when comparing the case with and without the desiccant rotor 41, 1 - (60.66 - 25.17) / (61.23 - 25.17) = 1 - 35.19 / 36.06 = 0.016, or 1.6% energy savings.

[0091] Furthermore, when the desiccant rotor 41 is used, the dew point temperature drops to +0.8°C, so if the desiccant rotor 41 is used as a desiccant, it will be understood that the vehicle window glass will be less likely to fog up, but as mentioned above, the absolute humidity will drop, making passengers feel uncomfortable.

[0092] (6) Control of the rotation speed of the desiccant rotor 41 by the control device 11 (part 1) Therefore, the control device 11 of the vehicle air conditioning device 1 of the present invention controls the rotation speed of the desiccant rotor 41 to maintain comfort in the vehicle cabin without fogging the vehicle window glass and to save energy by using the intermediate function of the desiccant rotor 41. Therefore, the control device 11 changes and adjusts the rotation speed of the desiccant rotor 41 so as to increase the humidity in the vehicle cabin as much as possible without fogging the vehicle window glass.

[0093] In this embodiment, the control device 11 controls the desiccant rotor motor 42 based on the window glass surface temperature Tw detected by the window glass surface temperature sensor 59 and the dew point temperature Td of the air near the window glass, and in winter, for example, the rotation speed of the desiccant rotor 41 is adjusted mainly to the aforementioned medium rotation speed range, i.e., the range of 100 rph to 500 rph, thereby utilizing the intermediate function of the desiccant rotor 41. The control device 11 then adjusts the rotation speed of the desiccant rotor 41 in a direction to increase the humidity in the vehicle interior within a range in which the dew point temperature Td of the air near the window glass does not exceed the window glass surface temperature Tw-α (a predetermined threshold value set based on the window glass surface temperature Tw).

[0094] An example of this will be described in detail below using the flowchart in Fig. 4. In step S1 of Fig. 4, the control device 11 calculates the dew point temperature Td of the air near the window glass from the air temperature and relative humidity near the window glass detected by the window glass air temperature sensor 61 and the window glass air humidity sensor 62.

[0095] Next, in step S2, the control device 11 sets a threshold value (Tw-α) obtained by subtracting a predetermined margin value α from the window glass surface temperature Tw detected by the window glass surface temperature sensor 59, and compares the dew point temperature Td calculated in step S1 with this threshold value (Tw-α). If the dew point temperature Td of the air near the window glass is lower than the threshold value (Tw-α), the control device 11 proceeds to step S4 and increases the rotation speed of the desiccant rotor 41 by one step. As a result, the function (intermediate function) of the desiccant rotor 41 approaches the total heat exchange function, and the humidity in the vehicle cabin increases.

[0096] On the other hand, if the dew-point temperature Td of the air near the window glass is equal to or higher than the threshold value (Tw-α), the process proceeds to step S3, where the rotation speed of the desiccant rotor 41 is reduced by one step. As a result, the function (intermediate function) of the desiccant rotor 41 approaches the desiccant function side, so the humidity inside the vehicle cabin decreases and the window glass becomes less likely to fog up.

[0097] In this way, the control device 11 adjusts the rotation speed of the desiccant rotor 41 in a direction that increases the humidity inside the vehicle cabin within a range in which the dew point temperature Td of the air near the window glass does not exceed the aforementioned threshold value (Tw-α), thereby increasing the humidity inside the vehicle cabin as much as possible within a range in which the vehicle's window glass does not fog up, thereby improving the comfort of the occupants.

[0098] As described above, in the present invention, the desiccant rotor 41 is arranged across the outside air passage 32 and the ventilation passage 37, and the control device 11 controls the rotation of the desiccant rotor 41 and changes its rotation speed. Therefore, by using the control device 11 to adjust the rotation speed of the desiccant rotor 41 in a direction that increases the humidity inside the vehicle cabin within a range that does not cause the vehicle window glass to fog up, it is possible to achieve efficient interior air conditioning while preventing the vehicle window glass from fogging up and improving the comfort of passengers inside the vehicle cabin without using complex operations.

[0099] In particular, in the present invention, the control device 11 rotates the desiccant rotor 41 at a predetermined high rotation speed to achieve the total heat exchange function, and rotates the desiccant rotor 41 at a predetermined medium rotation speed that is lower than the high rotation speed and higher than the predetermined low rotation speed at which the desiccant rotor 41 achieves the desiccant function to achieve the intermediate function of the desiccant rotor 41.Therefore, sensible heat exchange using the intermediate function of the desiccant rotor 41 makes it possible to exchange heat between the outside air and ventilation while suppressing a decrease in absolute humidity inside the vehicle cabin.

[0100] In the above embodiment, for example, in winter, the control device 11 adjusts the rotation speed of the desiccant rotor 41 based on the surface temperature Tw of the vehicle's window glass and the dew-point temperature Td of the air near the window glass, and adjusts the rotation speed of the desiccant rotor 41 in a direction to increase the humidity inside the vehicle cabin within a range in which the dew-point temperature Td of the air near the window glass does not exceed a predetermined threshold value (Tw-α) that is set based on the surface temperature Tw of the window glass.This makes it possible to achieve efficient vehicle cabin air conditioning without fogging up the vehicle's window glass, while maintaining high humidity inside the vehicle cabin and maintaining comfort.

[0101] In the above embodiment, this is achieved by increasing the rotation speed of the desiccant rotor 41 by one step when the dew-point temperature Td of the air near the window glass is lower than the threshold value (Tw-α), and decreasing the rotation speed of the desiccant rotor 41 by one step when the dew-point temperature Td is equal to or higher than the threshold value (Tw-α).

[0102] Furthermore, in this embodiment, the desiccant rotor 41 is positioned downstream of the indoor blower 34 in the flow of air circulating within the HVAC 10, and upstream of the temperature adjustment unit 30, which is composed of the radiator 4 and the heat absorber 9. This allows air before its temperature is adjusted by the temperature adjustment unit 30 to flow through the desiccant rotor 41, making it possible to properly exchange heat between the outside air and ventilation in the desiccant rotor 41.

[0103] Furthermore, in the embodiment, a bypass passage 38 is provided that bypasses the ventilation passage 37 and returns the inside air sucked into the HVAC 10 to the inside of the vehicle cabin, and a ventilation damper (flow rate adjusting device) 39 is provided that adjusts the flow rate of the air flowing through the ventilation passage 37 and the air flowing through the bypass passage 38. Therefore, by simply adjusting the amount of ventilation and the amount of inside air returned to the vehicle cabin with the ventilation damper 39, it becomes possible to circulate a ventilation amount that matches the amount of outside air introduced to the desiccant rotor 41.

[0104] (7) Control of the Rotation Speed ​​of the Desiccant Rotor 41 by the Control Device 11 (Part 2) In the above embodiment, the control device 11 controls the rotation speed of the desiccant rotor 41 based on the surface temperature Tw of the window glass and the dew point temperature Td of the air near the window glass. However, the rotation speed of the desiccant rotor 41 may also be controlled based on the absolute humidity and relative humidity of the outside air and inside air. In this case, the relative humidity of the outside air is detected by the outside air humidity sensor 56. The control device 11 calculates the absolute humidity of the outside air from the relative humidity and the outside air temperature detected by the outside air temperature sensor 54. Similarly, the relative humidity of the inside air is detected by the inside air humidity sensor 58, and the control device 11 calculates the absolute humidity of the inside air from the relative humidity and the inside air temperature detected by the inside air temperature sensor 57.

[0105] Then, for example, in the heating mode or ventilation mode in winter, when the absolute humidity of the outside air is lower than the absolute humidity of the inside air and the relative humidity of the outside air is higher than the relative humidity of the inside air, the control device 11 controls the desiccant rotor motor 42 to rotate the desiccant rotor 41 at a medium rotation speed, and sets the desiccant rotor 41 to the intermediate function described above. Even with this control, it is possible to prevent fogging of the vehicle window glass and improve comfort inside the vehicle by comparing the temperature and humidity of the outside air and the inside air without using complicated operations.

[0106] The absolute humidity of the outside air and the absolute humidity of the inside air are fed back to the controller 11, and if the absolute humidity of the outside air becomes higher than the absolute humidity of the inside air in cooling mode, dehumidifying cooling mode, or dehumidifying heating mode in summer, the controller 11 sets the rotation speed of the desiccant rotor 41 to a high speed to switch to the total heat exchange function. This allows the controller 11 to switch between the total heat exchange function and the intermediate function according to changes in the outside and inside air environments, enabling optimal operation in terms of air conditioning efficiency and comfort throughout the seasons.

[0107] (8) Another embodiment of the HVAC 10 Next, another embodiment of the HVAC 10 to which the present invention can be applied will be described with reference to Figure 9. In this embodiment, in addition to the HVAC 10 of the embodiment in Figure 1, a partition plate 72 is provided to separate the inside of the air flow passage 3 on the air downstream side of the desiccant rotor 41 into upper and lower parts. In this case, the insides of the heat absorber 9 and the radiator 4 are also separated into upper and lower parts, and the air mix damper 44 is also separated into upper and lower parts.

[0108] Furthermore, the partition plate 72 is cut out within the movable range of the DEF outlet damper 53, but when the DEF outlet damper 53 is made parallel to the partition plate 72 as shown in Figure 9, almost the entire air flow passage 3 on the air downstream side of the desiccant rotor 41 is divided into upper and lower sections.

[0109] As mentioned above, the DEF outlet 48 is located at the highest position in the HVAC 10, and the bypass passage 38 is located at the lowest position in the HVAC 10 (shown by the bold frame in Figure 9). Therefore, when the DEF outlet damper 53 is in the state shown in Figure 9, outside air with a low dew point temperature will be blown out from the DEF outlet 48.

[0110] 7, when the desiccant rotor 41 is set to the intermediate function in the heating mode, the temperature of the air blown out from the DEF outlet 48 is +50°C, the relative humidity is 3.5%, and the dew point temperature is low at -4.0°C. The temperature of the air (inside air) blown out from the FOOT outlet 46 is +50°C, the relative humidity is 7.7%, and the dew point temperature is +6.3°C.

[0111] By arranging the bypass passage 38 in the lower part of the HVAC 10 on the opposite side from the DEF outlet 48 formed in the upper part, for example, when the air flow passage 3 is divided into upper and lower parts as in this embodiment, air with a lower dew point temperature can be blown out from the DEF outlet 48, thereby reliably and quickly preventing fogging of the window glass. This also applies when the desiccant rotor 41 has a total heat exchange function or a desiccant function.

[0112] (9) Other Examples of Ventilation Damper 39 Although the ventilation damper 39 is configured as a rotary damper in each of the above-described embodiments, it may also be configured as a slide damper as shown in FIG.

[0113] Furthermore, the control of the desiccant rotor 41 in the first embodiment described above is not limited to this, and in inventions other than claims 6 to 8, for example, the rotation speed of the desiccant rotor 41 may be controlled in a direction to eliminate the deviation e using proportional integral derivative (PID) or proportional integral (PI) based on the deviation e between the dew point temperature Td of the air near the window glass and a threshold value (Tw-α) set based on the surface temperature Tw of the window glass, thereby finely adjusting the rotation speed of the desiccant rotor 41 in a direction to increase the humidity inside the vehicle cabin within a range where the window glass does not fog up.

[0114] Furthermore, the specific numerical values, structures, and configuration of the refrigerant circuit R shown in the embodiments are not limited to these, and it goes without saying that they can be modified as appropriate within the scope of the invention.

[0115] In particular, in the embodiment, the temperature adjustment unit 30 is formed by providing the radiator 4 and the heat absorber 9 in the HVAC 10, but this is not limiting. The radiator 4 for radiating heat from the refrigerant to heat the air circulating within the HVAC 10 and the heat absorber 9 for absorbing heat from the refrigerant to cool the air circulating within the HVAC 10 may be provided outside the HVAC 10, and a heat exchanger for heat radiation and a heat exchanger for heat absorption may be provided inside the HVAC 10, through which the heat medium circulated to the radiator 4 and the heat absorber 9 flows, respectively. In this case, the temperature adjustment unit 30 will include the heat radiator 4 and the heat absorber 9 as well as the heat exchanger for heat radiation and the heat exchanger for heat absorption, and the temperature adjustment unit 30 (part of the temperature adjustment unit 30) for the heat radiating heat exchanger and the heat absorbing heat exchanger will be provided inside the HVAC 10.

[0116] REFERENCE SIGNS LIST 1 Vehicle air conditioning device 2 Compressor 3 Air flow passage 4 Radiator 6 Outdoor expansion valve 7 Outdoor heat exchanger 8 Indoor expansion valve 9 Heat absorber 10 HVAC 11 Control device 26 Outdoor air intake port 27 Interior air intake port 28 Outdoor air damper 29 Interior air damper 30 Temperature adjustment unit 32 Outdoor air passage 33 Interior air passage 34 Interior blower (blower) 37 Ventilation passage 38 Bypass passage 39 Ventilation damper (flow rate adjustment device) 41 Desiccant rotor 42 Desiccant rotor motor 46 Foot outlet 47 Vent outlet 48 Deflection outlet 51 Foot outlet damper 52 Vent outlet damper 53 Deflection outlet damper R Refrigerant circuit

Claims

1. An air conditioning system for a vehicle comprising: an HVAC equipped with a blower and a temperature control unit for circulating air inside; an outside air passage configured within the HVAC through which outside air introduced into the HVAC circulates; a ventilation passage configured within the HVAC through which the inside air drawn into the HVAC is discharged to the outside of the vehicle cabin as ventilation; a desiccant rotor arranged across the outside air passage and the ventilation passage; and a control device for controlling the rotation of the desiccant rotor, wherein the control device changes the rotation speed of the desiccant rotor.

2. The vehicle air conditioning system according to claim 1, characterized in that the control device adjusts the rotation speed of the desiccant rotor in a direction to increase the humidity inside the vehicle cabin within a range that does not cause the vehicle's windows to fog up.

3. The vehicle air conditioning device described in claim 1, characterized in that the control device rotates the desiccant rotor at a predetermined high rotation speed to achieve a total heat exchange function, and rotates the desiccant rotor at a predetermined medium rotation speed that is lower than the high rotation speed and higher than the predetermined low rotation speed at which the desiccant rotor achieves the desiccant function to achieve an intermediate function.

4. The vehicle air conditioning system according to claim 3, characterized in that the control device adjusts the rotation speed of the desiccant rotor based on the surface temperature of the vehicle's window glass and the dew point temperature of the air near the window glass.

5. The vehicle air conditioning system described in claim 4, characterized in that the control device adjusts the rotation speed of the desiccant rotor in a direction to increase the humidity inside the vehicle cabin within a range in which the dew point temperature of the air near the window glass does not exceed a predetermined threshold value set based on the surface temperature of the window glass.

6. The vehicle air conditioning system of claim 5, characterized in that the control device increases the rotation speed of the desiccant rotor when the dew point temperature of the air near the window glass is lower than the threshold value, and decreases the rotation speed of the desiccant rotor when the dew point temperature of the air near the window glass is higher than the threshold value.

7. The vehicle air conditioning system of claim 3, characterized in that when the absolute humidity of the outside air is lower than the absolute humidity of the inside air and the relative humidity of the outside air is higher than the relative humidity of the inside air, the control device sets the rotation speed of the desiccant rotor to the medium rotation speed and sets the desiccant rotor to an intermediate function.

8. The vehicle air conditioning system described in claim 7, characterized in that when the absolute humidity of the outside air is higher than the absolute humidity of the inside air, the control device sets the rotation speed of the desiccant rotor to the high rotation speed and makes the desiccant rotor have a total heat exchange function.

9. A vehicle air conditioning system as described in any one of claims 1 to 8, characterized in that the desiccant rotor is positioned downstream of the blower and upstream of the temperature adjustment unit in the flow of air circulating within the HVAC.

10. The vehicle air conditioning system according to claim 9, characterized in that the temperature control unit comprises a radiator for dissipating heat from the refrigerant to heat the air circulating within the HVAC, and a heat sink for absorbing heat from the refrigerant to cool the air circulating within the HVAC.

11. A vehicle air conditioning system as described in any one of claims 1 to 8, characterized in that it is provided with a bypass passage that bypasses the ventilation passage and returns the inside air drawn into the HVAC to the inside of the vehicle cabin, and a flow rate adjusting device that adjusts the flow rate of air flowing through the ventilation passage and the air flowing through the bypass passage.

12. The vehicle air conditioning system according to claim 11, further comprising a DEF outlet for blowing air from the HVAC onto the vehicle window glass, and the bypass passage is located inside the HVAC on the opposite side from the DEF outlet.

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