Air conditioner for vehicle

Abstract

[Problem] To provide an air conditioner for a vehicle capable of efficiently air-conditioning a cabin while maintaining comfort and safety in the cabin by properly executing a defroster mode. [Solution] In the defroster mode, an outside air suction port 26 is closed by an inside / outside air switching damper 28, and inside air sucked from an inside air suction port 27 is blown out from a DEF blowout port 38. When the concentration of CO2 in the cabin becomes higher than a predetermined upper limit value set in advance, the outside air suction port 26 is opened by the inside / outside air switching damper 28, and an outside air introduction setting for introducing outside air is enabled.

Description

Vehicle air conditioning system

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

[0002] Conventional vehicle air conditioning systems have been designed to provide air conditioning by discharging cooled and heated air into the vehicle cabin through a temperature control unit, such as a radiator or a heat sink, that is located inside the HVAC, through which outside air is drawn in from outside the vehicle cabin and inside air is drawn in from inside the vehicle cabin. Furthermore, when the windshield, one of the vehicle's windows, becomes fogged up, a DEF outlet is provided to blow air from the HVAC onto the inside of the windshield, and a defroster mode is also provided in which air is blown out of the DEF outlet by the passenger's operation to defog the windshield (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2004-268790

[0004] Conventionally, this defroster mode would take in dry outside air and blow the warm, dry air that had passed through a heat absorber and radiator onto the windshield to prevent condensation. However, because it takes in outside air, in times such as rain, high humidity outside air flows into the vehicle interior, making it take time for the windshield to defog. In addition, the introduction of outside air increases the air conditioning load, which is a problem.

[0005] Therefore, if the introduction of outside air is not performed in the defroster mode and only internal air is circulated, the CO2 concentration in the vehicle cabin will increase due to the exhalation of the occupants, causing the occupants to feel uncomfortable and sleepy.

[0006] The present invention has been made to solve the above-mentioned conventional technical problems, and aims to provide a vehicle air conditioning system that can achieve efficient air conditioning in the vehicle cabin while maintaining comfort and safety in the vehicle cabin by appropriately executing the defroster mode.

[0007] The vehicle air conditioning system of the present invention comprises at least an HVAC equipped with a blower and a temperature control unit for circulating air inside, an outside air intake port for introducing outside air into the HVAC, an inside air intake port for drawing inside air into the HVAC, a damper device for controlling the introduction of outside air from the outside air intake port and the drawing of inside air from the inside air intake port, a DEF outlet for blowing air from the HVAC onto the vehicle window glass, and a control device having a defroster mode for blowing air circulating inside the HVAC from the DEF outlet, wherein the control device is characterized in that in the defroster mode, the damper device closes the outside air intake port and sets an inside air circulation setting in which the inside air drawn in from the inside air intake port is blown out from the DEF outlet, and when the CO2 concentration inside the vehicle cabin becomes higher than a predetermined upper limit value, the damper device opens the outside air intake port and sets an outside air introduction setting in which outside air is introduced from the outside air intake port.

[0008] The vehicle air conditioning system of the present invention is characterized in that the upper limit value is set based on the number of passengers.

[0009] The vehicle air conditioning system of the present invention is characterized in that the upper limit value is set higher as the number of passengers is smaller.

[0010] The vehicle air conditioning system of the invention of claim 4 is characterized in that in the invention of claim 1, the control device terminates the outside air introduction setting and returns to the inside air circulation setting when a preset outside air introduction time has elapsed.

[0011] In the vehicle air conditioning system of the present invention, the outside air introduction time is set to be shorter as the number of passengers is smaller.

[0012] The vehicle air conditioning system of the invention of claim 6 is characterized in that in each of the above inventions, the temperature adjustment unit has at least a heat absorber for absorbing heat from the refrigerant and cooling the air circulating within the HVAC, and the control device changes the evaporation temperature of the refrigerant in the heat absorber based on at least one of the humidity of the outside air, the humidity of the inside air, and the number of passengers.

[0013] The vehicle air conditioning system of the invention of claim 7 is characterized in that in the above invention, the control device changes the evaporation temperature of the refrigerant in the heat absorber to a lower value as the humidity of the outside air and / or the humidity of the inside air becomes higher.

[0014] The vehicle air conditioning system of the invention of claim 8 is the sixth invention, wherein the control device changes the evaporation temperature of the refrigerant in the heat absorber so as to decrease as the number of passengers increases.

[0015] According to the present invention, a vehicle air conditioning system includes at least an HVAC equipped with a blower and a temperature regulator for circulating air inside, an outside air inlet for introducing outside air into the HVAC, an inside air inlet for drawing inside air into the HVAC, a damper device for controlling the introduction of outside air through the outside air inlet and the drawing of inside air through the inside air inlet, a DEF outlet for blowing air from the HVAC to the vehicle windows, and a control device having a defroster mode for blowing air circulating inside the HVAC through the DEF outlet. In the defroster mode, the control device closes the outside air inlet using the damper device and sets an inside air circulation setting for blowing inside air drawn through the inside air inlet through the DEF outlet. This eliminates or reduces the problem of high-humidity outside air entering during rain, which adversely affects the window defogging effect in the defroster mode. Furthermore, this also eliminates or reduces an increase in air conditioning load, thereby saving energy.

[0016] Furthermore, when the CO2 concentration inside the vehicle cabin exceeds a predetermined upper limit, the damper device opens the outside air intake port, and the outside air is introduced through the outside air intake port. This eliminates the inconvenience of passenger discomfort and drowsiness caused by an increase in CO2 concentration inside the vehicle cabin due to the inside air recirculation setting. In this way, the present invention makes it possible to achieve efficient vehicle cabin air conditioning while maintaining comfort and safety inside the vehicle by appropriately operating the defroster mode.

[0017] In this case, as in the invention of claim 2, the upper limit value can be set based on the number of passengers, and further, as in the invention of claim 3, the upper limit value can be set higher the fewer the number of passengers, thereby delaying the timing at which the introduction of outside air begins, and minimizing the inconveniences of a deterioration in the effectiveness of de-fogging the window glass and an increase in the air conditioning load.

[0018] Furthermore, as in the invention of claim 4, when the preset outside air introduction time has elapsed, the outside air introduction setting is terminated and the setting is returned to the inside air circulation setting, and as in the invention of claim 5, the outside air introduction time can be set shorter the fewer the number of passengers, thereby making it possible to keep the amount of outside air introduction to the minimum necessary, further minimizing the inconvenience of a deterioration in the window defogging effect and an increase in the air conditioning load.

[0019] Furthermore, as in the invention of claim 6, if the temperature adjustment unit is configured as a heat absorber for absorbing heat from the refrigerant to cool the air circulating inside the HVAC, and the control device is configured to change the evaporation temperature of the refrigerant in the heat absorber based on at least one of the humidity of the outside air, the humidity of the inside air, and the number of passengers, then, for example, as in the invention of claim 7, the control device will change the evaporation temperature of the refrigerant in the heat absorber to be lower the higher the humidity of the outside air and / or the humidity of the inside air, thereby minimizing the increase in the load on the heat absorber while making the highly humid outside air and inside air as dry as possible and improving the anti-fogging effect of the window glass.

[0020] Alternatively, as in claim 8, the control device may be configured to lower the evaporation temperature of the refrigerant in the heat absorber as the number of passengers increases, thereby minimizing the increase in the load on the heat absorber and suppressing the increase in humidity inside the vehicle cabin due to the breath of the passengers, thereby improving the anti-fogging effect of the window glass.

[0021] 1 is a schematic diagram of an HVAC for a vehicle air conditioning device according to an embodiment of the present invention (Example 1); FIG. 2 is a refrigerant circuit diagram for the vehicle air conditioning device of FIG. 1; FIG. 3 is a block diagram of a control device for the vehicle air conditioning device of FIG. 1; FIG. 4 is a flowchart illustrating an example of control in defroster mode executed by the control device of FIG. 3; FIG. 5 is a graph illustrating the change in CO2 concentration over time in the vehicle cabin for each number of occupants when 50% outside air is introduced; and FIG. 6 is a numerical diagram illustrating the change in CO2 concentration over time in the vehicle cabin for each number of occupants when 50% outside air is introduced.

[0022] An embodiment of the present invention will be described in detail below with reference to the drawings. The vehicle air conditioning system 1 of the embodiment is for an electric vehicle that cannot use engine waste heat for heating. The system operates in a heating mode by a heat pump using a refrigerant circuit, and selectively operates in one of three operating modes: a dehumidifying heating mode, a dehumidifying cooling mode, a cooling mode, and a ventilation mode. The vehicle is not limited to electric vehicles; the present invention is also effective for so-called hybrid vehicles that use both an engine and an electric motor for traction, and it goes without saying that the present invention can also be applied to ordinary vehicles that run on an engine.

[0023] 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) in the present invention. The outdoor heat exchanger 7 is provided with an outdoor blower 15.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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 port 26 for introducing outside air into the air flow passage 3 and an inside air intake port 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 inside / outside air switching damper 28 is provided as a damper device for adjusting the opening (degree of opening) of the outside air intake port 26 and the inside air intake port 27 to control the ratio of outside air and inside air circulating in the air flow passage 3.

[0029] In this embodiment, the inside / outside air switching damper 28 can be used to switch between an inside air circulation setting in which the opening of the inside air intake 27 is 100% and the opening of the outside air intake 26 is 0% (0% outside air introduction), i.e., the outside air intake 26 is closed and only the inside air from within the passenger compartment is drawn into the air flow passage 3 and the drawn inside air is blown out again into the passenger compartment for circulation, and an outside air introduction setting in which the outside air intake 26 is opened and outside air is introduced into the air flow passage 3.

[0030] In this fresh air introduction setting, the opening degree of the fresh air intake port 26 can be changed within a range greater than 0% and less than or equal to 100%. When the opening degree of the fresh air intake port 26 is 50% (fresh air introduction 50%), the opening degree of the inside air intake port 27 is also 50%, and half of the fresh air and half of the inside air are mixed and circulate through the air flow passage 3. When the opening degree of the fresh air intake port 26 is set to 100% (fresh air introduction 100%), the opening degree of the inside air intake port 27 is 0%, and only fresh air circulates through the air flow passage 3 and is blown into the vehicle cabin.

[0031] In the figure, reference numeral 31 denotes a filter provided in the air flow passage 3 downstream of each intake port 26, 27 of the HVAC 10, and reference numeral 32 denotes an interior blower (a blower in the present invention) provided in the HVAC 10 downstream of the filter 31 for circulating air through the air flow passage 3. When the interior blower 32 is operated, outside air is introduced into the air flow passage 3 through the outside air intake port 26, and air from within the vehicle cabin, i.e., inside air, is drawn into the air flow passage 3 through the inside air intake port 27.

[0032] A heat absorber 9 constituting the temperature adjustment unit 30 is provided in the air flow passage 3 downstream of the indoor blower 32, and a radiator 4 also constituting the temperature adjustment unit 30 is provided downstream of the heat absorber 9. A heating passage 33 and a bypass passage 34 are formed in the air flow passage 3, and the radiator 4 is provided in the heating passage 33. An air mix damper 36 is provided in the air flow passage 3 upstream of the radiator 4 to adjust the ratio of air (indoor air or outdoor air) that has passed through the heat absorber 9 to be ventilated through the heating passage 33 and the bypass passage 34.

[0033] Furthermore, the HVAC 10 on the downstream side of the radiator 4 is formed with a FOOT outlet, a VENT outlet (representatively indicated by reference numeral 37 in FIG. 1 ), and a DEF outlet 38. The FOOT outlet is an outlet for blowing air toward the feet of the passenger compartment, and the VENT outlet is an outlet for blowing air toward the chest and face of the passenger inside the passenger compartment. The DEF outlet 38 is an outlet for blowing air toward the inner surface of the vehicle's window glass (windshield), and is located higher than the other outlets, at the highest position in the HVAC 10.

[0034] In the figure, reference numeral 39 denotes an outlet switching damper that adjusts the proportion of air blown into the vehicle cabin from each of the outlets 37, 38. In this case, in a defroster mode (described later), the outlet switching damper 39 is configured to block air flowing toward the foot outlet and vent outlet, and to blow air only from the defroster outlet 38.

[0035] 3 is a block diagram showing the control device 11 of the vehicle air conditioning system 1 of the embodiment. The control device 11 is composed of a microcomputer, which is an example of a computer equipped with a processor, and also has a memory as a storage device. The inputs to the control device 11 include an outside air temperature sensor 41 that detects the temperature of the outside air (outside air temperature) introduced through the outside air inlet 26, an outside air humidity sensor 42 that detects the humidity of the outside air (outside air humidity), an inside air temperature sensor 43 that detects the temperature of the inside air (air inside the vehicle cabin) drawn through the inside air inlet 27 (inside air temperature), an inside air humidity sensor 44 that detects the humidity of the inside air (inside air humidity), a refrigerant circuit temperature sensor 46 that detects the temperature of each part of the refrigerant circuit R (actually, a single sensor is shown), and a refrigerant circuit pressure sensor 47 that detects the refrigerant pressure of each part of the refrigerant circuit R (also in actuality). are provided in various parts of the refrigerant circuit R, but only one is shown as a representative example. The HVAC 10 also includes a blown air temperature sensor 48 for detecting the temperature of air blown into the vehicle cabin from the HVAC 10, an interior CO2 concentration sensor 49 for detecting the CO2 (carbon dioxide) concentration in the vehicle cabin, a solar radiation sensor 51, such as a photosensor, for detecting the amount of solar radiation entering the vehicle cabin, a vehicle speed sensor 52 for detecting the vehicle's speed, an occupant sensor 53 provided on a seat in the vehicle cabin for detecting the presence or absence of an occupant, and an air conditioning (air conditioner) operation unit 54 for setting the set temperature and switching the operating mode. In this embodiment, the occupant sensor 53 is a weight sensor that detects the number of occupants by measuring their weight when they are seated. Also, reference numeral 56 in FIG. 3 denotes a defroster switch provided on the air conditioning operation unit 54.

[0036] In addition, the output of the control device 11 is connected to the compressor 2, the outdoor blower 15, the indoor blower (blower) 32, each solenoid valve 22, 21, 17, 20, the outdoor expansion valve 6, the indoor expansion valve 8, the inside / outside air switching damper 28, the outlet switching damper 39, and the air mix damper 36, all of which are controlled by the control device 11.

[0037] 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.

[0038] (1) Heating Mode When the heating mode is selected by the control device 11 or manually by operating the air conditioning operation unit 54, 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 32 are operated, and the air mix damper 36 is set in a state where the air blown out from the indoor blower 32 is ventilated to the radiator 4.

[0039] 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.

[0040] 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 drawn into the compressor 2, repeating this cycle. The air heated by the radiator 4 is blown out from the air outlets 37, 38, thereby heating the passenger compartment.

[0041] 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 47, 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 46 and the refrigerant pressure of the radiator 4 detected by the refrigerant circuit pressure sensor 47, thereby controlling the degree of subcooling of the refrigerant at the outlet of the radiator 4.

[0042] (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 32 condenses and adheres to the heat absorber 9, so the air is cooled and dehumidified.

[0043] 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 passes through the accumulator 12 and is drawn into the compressor 2, repeating this circulation. 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 47, 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 46.

[0044] (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, 32 are operated, and the air mix damper 36 is set in a state where the air blown from the indoor blower 32 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.

[0045] 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.

[0046] 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 32 condenses and adheres to the heat absorber 9, so the air is cooled and dehumidified.

[0047] 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 46, 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.

[0048] (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 36 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.

[0049] 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.

[0050] 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 32 condenses and adheres to the heat absorber 9, so the air is cooled.

[0051] 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 passes little or no through the radiator 4 and is blown into the passenger compartment from the air outlets 37, 38, 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 46.

[0052] At startup, the control device 11 selects an operation mode based on the outside air temperature and the target blow-out temperature TAO detected by the refrigerant circuit temperature sensor 46. 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 outside air temperature and the target blow-out temperature TAO.

[0053] (5) Defroster Mode: In the above-described air-conditioning operation, when the windshield begins to fog up and the passenger operates the defroster switch 56 of the air-conditioning operation unit 54, the following operation will be described with reference to Figures 4 to 6. As mentioned above, when the outside air is introduced in the defroster mode under conditions of high outside humidity, such as during rainfall, it actually makes it more difficult to defog the windshield. Furthermore, in winter, for example, introducing cold outside air increases the air-conditioning load inside the vehicle cabin.

[0054] Therefore, when the control device 11 starts the defroster mode, it basically sets the inside / outside air switching damper 28 to the above-mentioned inside air recirculation setting. However, with the inside air recirculation setting, only inside air is circulated into the vehicle cabin, which causes the CO2 concentration in the vehicle cabin to rise due to the occupants' exhalation. In such cases, it is generally said that it is preferable to keep the CO2 concentration in the vehicle cabin below 1000 ppm to 2000 ppm, because if the CO2 concentration in the vehicle cabin exceeds 2500 ppm, occupants will begin to feel uncomfortable, and this can lead to decreased attention, poor judgment, and drowsiness.

[0055] Therefore, in the present invention, the inside / outside air switching damper 28 is switched to the outside air introduction setting based on the CO2 concentration inside the vehicle cabin. In this embodiment, the upper limit value of the CO2 concentration inside the vehicle cabin and the outside air introduction time are obtained in advance by experiment and stored in the memory of the control device 11. When the CO2 concentration inside the vehicle cabin rises to this upper limit value, outside air is introduced for the outside air introduction time.

[0056] (5-1) Setting the Upper Limit of CO2 Concentration in the Vehicle Cabin and the Outside Air Intake Time Here, the CO2 concentration in the vehicle cabin increases due to the exhalation of the occupants, so it depends on the number of occupants. The more occupants there are, the faster the concentration increases. However, when outside air is introduced, the fewer occupants there are, the faster the concentration decreases. Figure 5 shows the change in CO2 concentration in the vehicle cabin when the inside / outside air switching damper 28 is set to the inside air circulation setting, and then the inside / outside air switching damper 28 is used to open the outside air intake 26 to 50%, i.e., to introduce 50% outside air. Figure 6 also shows the change in CO2 concentration in the vehicle cabin after the inside / outside air switching damper 28 is set to introduce 50% outside air, as numerical values, for each number of occupants.

[0057] In Figure 5, the solid line represents the case where there is one occupant, the dashed line represents the case where there are two occupants, and the dashed line represents the case where there are four occupants. In Figure 5, if the CO2 concentration in the vehicle cabin is 500 ppm and the inside / outside air switching damper 28 is set to the inside air recirculation setting (defroster mode is started), the CO2 concentration in the vehicle cabin will gradually increase when there is one occupant. If the CO2 concentration in the vehicle cabin is then 2000 ppm and the inside / outside air switching damper 28 is set to the outside air intake setting with 50% outside air intake, the CO2 concentration in the vehicle cabin will rapidly decrease (the circled portion in Figure 5; the same applies below), and will fall below 1100 ppm after two minutes, as shown in Figure 6.

[0058] When there are two occupants, the CO2 concentration in the vehicle cabin rises more quickly than when there is only one occupant. If the CO2 concentration in the vehicle cabin then reaches 1800 ppm and the inside / outside air switching damper 28 is set to allow 50% outside air, the CO2 concentration in the vehicle cabin will drop more quickly, albeit more slowly than when there is only one occupant, and will fall below 1100 ppm after three minutes, as shown in Figure 6.

[0059] Although the case where there are three occupants is not shown in Figure 5, the same tendency is observed, with the CO2 concentration in the vehicle cabin increasing more quickly than when there are two occupants. If the CO2 concentration in the vehicle cabin then reaches 1600 ppm and the inside / outside air switching damper 28 is set to introduce 50% outside air, the rate at which the CO2 concentration in the vehicle cabin decreases becomes more gradual than when there are two occupants, and after seven minutes, the concentration remains almost constant at around 1100 ppm, as shown in Figure 6.

[0060] When there are four passengers, the CO2 concentration in the vehicle cabin rises rapidly due to the exhalations of the four passengers, as shown in Figure 5. Even if the inside / outside air switching damper 28 is then set to introduce 50% outside air when the CO2 concentration in the vehicle cabin reaches 1400 ppm, the CO2 concentration in the vehicle cabin drops to around 1300 ppm as shown in Figure 6, and then remains almost constant.

[0061] Therefore, in this embodiment, the upper limit of the CO2 concentration in the vehicle cabin for setting the outside air introduction setting in the defroster mode is set for each number of occupants. In addition, the outside air introduction time in the defroster mode is also set for each number of occupants and stored in the memory of the control device 11. For example, specific values ​​are as follows. Upper limit: 1 occupant: 2000 ppm 2 occupants: 1800 ppm 3 occupants: 1600 ppm 4 occupants: 1400 ppm Outside air introduction time: 1 occupant: 2 minutes 2 occupants: 3 minutes 3 occupants: 7 minutes 4 occupants: continuous

[0062] That is, the upper limit of the CO2 concentration in the vehicle cabin is set as high as possible within a range that takes safety into consideration as the number of occupants decreases. Also, the outside air introduction time is set to a shorter value as the number of occupants decreases. That is, in the defroster mode, the outside air introduction time is set to be as short as possible.

[0063] (5-2) Setting Control of Outside Air Intake in Defroster Mode With the above configuration, the operation of the defroster mode by the control device 11 will now be described with reference to the flowchart in Figure 4. When the defroster switch 56 of the air conditioning operation unit 54 is operated by a passenger, the control device 11 enters the defroster mode, and first, the outlet switching damper 39 blocks air from flowing toward the FOOT outlet and the VENT outlet, so that air is blown out only from the DEF outlet 38.

[0064] 4, the refrigerant circuit R is set to the dehumidifying heating mode, the dehumidifying cooling mode, or the cooling mode to start air conditioning operation (A / C: ON). If the heating mode is currently selected, the mode is switched to the dehumidifying heating mode. That is, the operation mode is set to evaporate the refrigerant at least in the heat absorber 9 to exert the dehumidifying capacity.

[0065] Next, in step S2, the inside / outside air switching damper 28 closes the outside air intake 26, and the opening of the inside air intake 27 is set to 100%, setting the inside air circulation mode. As a result, in the defroster mode, the air inside the vehicle cabin (inside air) drawn into the air flow passage 3 of the HVAC 10 from the inside air intake 27 basically flows into the heat absorber 9 via the filter 31 and the interior blower 32, where it is cooled / dehumidified, and then heated (reheated) by the radiator 4, becoming warm, dry air that is then blown out from the DEF outlet 38 onto the inside of the window glass (windshield).

[0066] Next, the control device 11 acquires information regarding the number of occupants in the vehicle cabin detected by the occupant sensor 53. Then, in step S5, the CO2 concentration of the air in the vehicle cabin detected by the interior CO2 concentration sensor 49 is taken in and a determination is made as to whether the CO2 concentration is equal to or less than the upper limit value for each number of occupants described above. That is, if the number of occupants detected by the occupant sensor 53 is one, the determination is made as to whether the CO2 concentration is equal to or less than 2000 ppm; if the number of occupants is two, the determination is made as to whether the CO2 concentration is equal to or less than 1800 ppm; if the number of occupants is three, the determination is made as to whether the CO2 concentration is equal to or less than 1600 ppm; and if the number of occupants is four, the determination is made as to whether the CO2 concentration is equal to or less than the upper limit value. If the CO2 concentration is equal to or less than the upper limit value, the process returns to step S3 and is repeated thereafter.

[0067] When the defroster mode is started and the inside / outside air switching damper 28 is set to the inside air circulation setting, the CO2 concentration in the air inside the vehicle cabin increases as described above. If the CO2 concentration exceeds the upper limit in step S5, the control device 11 proceeds to step S6, and in this embodiment, the inside / outside air switching damper 28 is set to the outside air introduction setting of 50%. As a result, the opening degree of the outside air intake 26 is set to 50%, and the opening degree of the inside air intake 27 is also set to 50%, so that the outside air is introduced and mixed with the inside air in equal proportions, and the air circulates through the air flow passage 3.

[0068] Next, the control device 11 proceeds to step S7 and determines whether the information regarding the number of occupants acquired in step S3 is four or more. If the number of occupants is four or more, the control device 11 proceeds to step S8 and continues to set the outside air intake ratio to 50%. This is because, as mentioned above, when there are four occupants, the CO2 concentration will not fall below 1,300 ppm even if the outside air intake ratio is set to 50%.

[0069] On the other hand, if the number of passengers is less than four in step S7, the control device 11 proceeds to step S9 and sets the outside air introduction time for 50% outside air introduction for each number of passengers. In this case, as described above, the time is set to 2 minutes if there is one passenger, 3 minutes if there are two passengers, and 7 minutes if there are three passengers.

[0070] Next, the control device 11 proceeds to step S10, and executes the outside air introduction setting of 50% outside air introduction until the outside air introduction time set for each number of passengers ends, and if the outside air introduction time has elapsed, proceeds to step S11 and returns the inside / outside air switching damper 28 to the inside air circulation setting.

[0071] As described above, in the present invention, the control device 11 closes the outside air intake 26 using the inside / outside air switching damper 28 in the defroster mode, and sets the inside air circulation setting so that the inside air drawn in through the inside air intake 27 is blown out through the DEF outlet 38. This eliminates or reduces the inconvenience of high-humidity outside air entering during rain, etc., which adversely affects the window defogging effect in the defroster mode. Furthermore, the increase in air conditioning load due to the inflow of outside air can be eliminated or reduced, contributing to energy savings.

[0072] Furthermore, when the CO2 concentration in the vehicle cabin becomes higher than the upper limit set as described above, the inside / outside air switching damper 28 opens the outside air intake 26 to introduce outside air, thereby eliminating the inconvenience of passenger discomfort and drowsiness caused by an increase in CO2 concentration due to the inside air circulation setting. In other words, according to the present invention, efficient vehicle cabin air conditioning can be achieved while maintaining comfort and safety in the vehicle cabin by appropriately operating the defroster mode.

[0073] In this case, in the embodiment, the upper limit value is set based on the number of passengers, and further, the lower the number of passengers, the higher the upper limit value is set. This makes it possible to delay the timing at which the introduction of outside air begins, even if only slightly, and minimize the inconvenience of a deterioration in the effectiveness of de-fogging the window glass and an increase in the air conditioning load.

[0074] In addition, in the embodiment, when a preset outside air introduction time has elapsed, the outside air introduction setting is terminated and the setting is returned to the inside air circulation setting, and the outside air introduction time is set to be shorter the fewer the number of passengers.This makes it possible to keep the amount of outside air introduction to the minimum necessary, further minimizing the inconvenience of a deterioration in the effectiveness of de-fogging the window glass and an increase in the air conditioning load.

[0075] (5-3) Opening Control of the Outside Air Intake Port 26 In the above embodiment, when the outside air intake setting is set in defroster mode, the opening of the outside air intake port 26 by the inside / outside air switching damper 28 is fixed to 50% (outside air intake 50%). However, this is not limiting, and the opening of the outside air intake port 26 may be changed by controlling the inside / outside air switching damper 28 for each number of passengers.

[0076] For example, when there is one occupant, the opening degree of the outside air intake 26 is set to 50% (50% outside air intake), when there are two occupants the opening degree is set to 70% (70% outside air intake), and when there are three or more occupants the opening degree is set to 100% (100% outside air intake). In other words, the more occupants there are, the greater the proportion of outside air blown into the vehicle cabin from the air flow passage 3, and the more quickly the CO2 concentration in the air inside the vehicle cabin can be reduced.

[0077] The invention relating to the above configuration can be claimed as a dependent claim of the present invention as follows: That is, a vehicle air conditioning system dependent on the present invention, characterized in that the control device changes the opening degree of the outside air intake port using the damper device based on the number of passengers. A vehicle air conditioning system dependent on the above invention, characterized in that the control device increases the opening degree of the outside air intake port as the number of passengers increases.

[0078] As described above, if the control device changes the opening degree of the outside air intake port using the damper device based on the number of passengers, for example, the more passengers there are, the larger the opening degree of the outside air intake port will be, thereby more quickly reducing the CO2 concentration in the vehicle cabin and further ensuring comfort and safety in the vehicle cabin.

[0079] (5-4) Control of Refrigerant Evaporation Temperature of Heat Absorber 9 In addition, in the defroster mode described above, the control device 11 may change the refrigerant evaporation temperature in the heat absorber 9 in accordance with the humidity of the outside air and the inside air detected by the outside air humidity sensor 42 and the inside air humidity sensor 44, and the number of occupants detected by the occupant sensor 53. In this case, the control device 11 throttles the indoor expansion valve 8 to lower the evaporation temperature of the refrigerant in the heat absorber 9, for example, the higher the humidity of the outside air and / or the humidity of the inside air. This makes it possible to dry the highly humid outside air and inside air as much as possible while minimizing the increase in the load on the heat absorber 9, thereby improving the anti-fogging effect of the window glass.

[0080] Alternatively, or in addition, the evaporation temperature of the heat absorber 9 may be changed so as to decrease as the number of passengers increases. This increases the dehumidifying effect of the heat absorber 9, thereby minimizing the increase in the load on the heat absorber 9 and suppressing the increase in humidity inside the vehicle cabin due to the breath of the passengers, thereby improving the anti-fogging effect of the window glass.

[0081] It goes without saying that the specific numerical values, the structure of the HVAC 10, and the configuration of the refrigerant circuit R shown in the embodiment are not limited to those shown therein, and can be appropriately changed without departing from the spirit of the present invention. For example, in the embodiment, the opening degrees of the outside air intake 26 and the inside air intake 27 are changed by the inside / outside air switching damper 28, but it is also possible to provide an outside air damper and an inside air damper at the outside air intake 26 and the inside air intake 27, respectively, so that the opening degrees of each intake can be changed independently.

[0082] Furthermore, in the embodiment, the HVAC 10 is provided with a radiator 4 and a heat absorber 9 to form the temperature adjustment unit 30, 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, respectively, flows.

[0083] In this case, the temperature adjustment unit 30 will include not only the radiator 4 and the heat absorber 9, but also a heat exchanger for heat radiation and a heat exchanger for heat absorption, and the temperature adjustment unit 30 (part of the temperature adjustment unit 30) for these heat exchangers for heat radiation and heat absorption will be provided within the HVAC 10.

[0084] DESCRIPTION OF SYMBOLS 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 Interior / exterior air switching damper (damper device) 30 Temperature adjustment unit 32 Interior blower (blower) 38 DEF outlet 39 Outlet switching damper R Refrigerant circuit

Claims

1. A vehicle air conditioning system comprising at least an HVAC equipped with a blower for circulating air inside and a temperature adjustment unit, an outside air intake port for introducing outside air into the HVAC, an inside air intake port for drawing inside air into the HVAC, a damper device for controlling the introduction of outside air from the outside air intake port and the drawing of inside air from the inside air intake port, a DEF outlet for blowing air from the HVAC onto the vehicle window glass, and a control device having a defroster mode for blowing air circulating inside the HVAC from the DEF outlet, wherein the control device, in the defroster mode, closes the outside air intake port using the damper device and sets an inside air circulation setting for blowing inside air drawn in from the inside air intake port out of the DEF outlet, When the CO2 concentration in the vehicle cabin becomes higher than a predetermined upper limit value, the damper device opens the outside air intake port, and an outside air intake setting is set to introduce outside air through the outside air intake port.

2. The vehicle air conditioning system according to claim 1, wherein the upper limit is set based on the number of passengers.

3. The vehicle air conditioning system according to claim 2, wherein the upper limit value is set higher as the number of passengers decreases.

4. The vehicle air conditioning system according to claim 1, characterized in that the control device terminates the outside air introduction setting and returns to the inside air circulation setting when a preset outside air introduction time has elapsed.

5. The vehicle air conditioning system according to claim 4, wherein the outside air introduction time is set to be shorter as the number of passengers is smaller.

6. A vehicle air conditioning system as described in any one of claims 1 to 5, characterized in that the temperature adjustment unit has at least a heat absorber for absorbing heat from a refrigerant to cool the air circulating within the HVAC, and the control device changes the evaporation temperature of the refrigerant in the heat absorber based on at least one of the humidity of the outside air, the humidity of the inside air, and the number of passengers.

7. The vehicle air conditioning system according to claim 6, characterized in that the control device changes the evaporation temperature of the refrigerant in the heat absorber to a lower value as the humidity of the outside air and / or the humidity of the inside air increases.

8. The vehicle air conditioning system according to claim 6, wherein the control device changes the evaporation temperature of the refrigerant in the heat absorber so that the evaporation temperature decreases as the number of passengers increases.

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