JP2005186923A - Vehicular air-conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a vehicular interior at suitable temperature and humidity, to avoid dew condensation on window pane, and to minimize energy consumed by driving of a cooling means. <P>SOLUTION: A window pane dew point vehicular interior absolute humidity Xrmax at which no dew is formed on the window pane is obtained (a step S2). A temporary vehicular interior setting absolute humidity (a temporary Xset) is calculated from a vehicular interior upper limit relative humidity allowed at a vehicular interior setting temperature Tset (a step S3). Either smaller one of the window pane dew point vehicular interior absolute humidity Xrmax or the temporary vehicular interior setting absolute humidity (a temporary Xset) is made to be a vehicular interior setting absolute humidity Xset (steps S4, S5). A blow-off air requiring absolute humidity Xao required for obtaining the vehicular interior setting absolute humidity Xset is calculated by considering outside air humidity entering the vehicular interior (a step 7). The obtained blow-off air requiring absolute humidity Xao and a blow-off air requiring temperature Tao required for obtaining the vehicular interior setting temperature Tset are used to obtain a control temperature Tea for controlling a compressor (steps S9, S12, S14, S15). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vehicle air conditioner that controls a cooling means and a heating means to adjust a vehicle interior temperature and a vehicle interior humidity in a state in which the window glass is not fogged.

  A vehicle air conditioner combines an evaporator that cools air using the vaporization heat of a refrigerant and dehumidifies it with a heater that heats air using the heat of engine cooling water. Adjust temperature and humidity.

  By the way, when the temperature is low and the control is performed so that the cooling capacity by the evaporator is lowered, the dehumidifying action is also reduced. For example, in a state where the temperature is low and the humidity is high, the water vapor in the passenger compartment becomes window glass or the like. There is a possibility of condensation.

  In order to solve this problem, a technology has been developed that maintains sufficient dehumidifying action without causing condensation, prevents the window glass from fogging, and reduces energy consumption by suppressing cooling more than necessary (patent). Reference 1).

  That is, in the above-described conventional technology, the surface temperature of the window glass is estimated, the required humidity of the blown air that becomes the humidity in the vehicle interior that does not condense at this temperature is calculated, and then the dew point temperature of the air that indicates the calculated required blown air humidity Thus, control is performed so that the lower of the required temperature of the blown air necessary for controlling the vehicle interior temperature to the set temperature and the dew point temperature is set as the control temperature of the evaporator. In this prior art, when calculating the required humidity of the blown air, the humidity set in the vehicle interior and the vehicle interior humidity detected by the vehicle interior humidity sensor are used.

Japanese Patent No. 3298151 (paragraphs [0009] and [0024])

  However, if the blowout temperature required to control the vehicle interior temperature to the set temperature is lower than the blowout air temperature, which is the humidity in the vehicle compartment where the window glass surface does not condense, the vehicle High indoor humidity may impair passenger comfort.

  On the other hand, if the air condition in the passenger compartment is below the humidity at which the window glass is condensed, below the set temperature by the passenger, and below the humidity at which the passenger feels uncomfortable, there is no need for further cooling and dehumidification. There is still room for energy saving by controlling the cooling capacity of the evaporator.

  In addition, in the process of determining the temperature of the blown air, which is the humidity in the passenger compartment where the window glass surface does not condense, if the humidity of the outside air entering the passenger compartment is not taken into account, the blown air is affected by the change in humidity. Since the required humidity cannot be calculated with high accuracy, the cooling capacity may be excessively controlled, or the required dehumidification amount may not be obtained.

  The present invention has been made to solve the above-mentioned problems, and can control the interior of the vehicle to an appropriate temperature and humidity, avoid condensation on the window glass, and minimize energy consumption. An object of the present invention is to provide a vehicular air conditioner that can be used.

In order to achieve the above object, the present invention comprises heating means for heating air,
Cooling means for cooling the air;
A window glass vehicle interior surface temperature acquisition means for acquiring a window glass vehicle interior surface temperature Tg;
Window glass dew point vehicle interior absolute humidity obtaining means for obtaining window glass dew point vehicle interior absolute humidity Xrmax with the window glass vehicle interior surface temperature Tg as a dew point;
Provisional vehicle interior setting absolute humidity acquisition means for obtaining provisional vehicle interior setting absolute humidity (provisional Xset) relative to the vehicle interior allowable upper limit relative humidity at the vehicle interior setting temperature Tset;
If Xrmax> temporary Xset, then Xset = temporary Xset, and if Xrmax ≦ temporary Xset, if Xset = Xrmax, vehicle interior setting absolute humidity setting means for setting the vehicle interior setting absolute humidity Xset;
Vehicle interior absolute humidity acquisition means for acquiring vehicle interior absolute humidity Xr;
The required air temperature Tao required for obtaining the vehicle interior set temperature Tset,
Tao = Ktset / Tset / Ktr / Tr-Ktam / Tam
-Kts ・ Ts-Ct
Ktset: Car interior set temperature coefficient
Ktr: Vehicle interior temperature sensor coefficient
Ktam: outside temperature sensor coefficient
Kts: Solar radiation sensor coefficient
Ct: Temperature calculation coefficient
Tr: Interior temperature
Tam: outside air temperature
Ts: means for calculating required air temperature for calculating the amount of solar radiation;
Blowing air required absolute humidity Xao necessary to obtain the vehicle interior setting absolute humidity Xset,
Xao = Kxset, Xset-Kxr, Xr-Kxam, Tam-Cx1
Kxset: Car interior setting absolute humidity coefficient
Kxr: Absolute humidity coefficient in the passenger compartment
Kxam: outside air absolute humidity coefficient
Cx1: means for calculating required absolute humidity of blown air to be calculated as a humidity calculation coefficient;
Control temperature calculation means for calculating the control temperature Tea of the air cooled by the cooling means based on the blown air required temperature Tao and the blown air required absolute humidity Xao;
Cooling control means for controlling the cooling capacity based on the control temperature Tea;
Heating control means for controlling the heating capacity based on the control temperature Tea;
It is characterized by providing.

  In the present invention, the vehicle interior is controlled to the comfortable humidity by taking into consideration the vehicle interior allowable upper limit relative humidity that is the upper limit of the vehicle interior comfort humidity as the control target of the air in the vehicle interior. Moreover, the cooling and dehumidification more than necessary by the cooling means are suppressed based on the temperature and humidity conditions in the passenger compartment. Furthermore, the required humidity of the blown air is obtained with high accuracy in consideration of the outside air humidity entering the vehicle interior. Thereby, while being able to control a vehicle interior to appropriate temperature and humidity, the condensation of a window glass can be avoided and the energy consumed by the drive of a cooling means can be made into the required minimum.

  FIG. 1 shows a vehicle 12 equipped with a vehicle air conditioner 10 of the present embodiment. As shown in FIG. 2, the vehicle air conditioner 10 includes an air conditioner ECU (Electronic Control Unit) 14 and an air conditioner unit 16 that adjusts the temperature, humidity, and air flow rate of air based on the control of the air conditioner ECU 14. The air conditioning unit 16 is supplied with cooling water from the engine 18.

  The air conditioner ECU 14 is connected to an operation display unit 20 for accepting operations such as temperature setting, air flow setting, and mode switching by an occupant of the vehicle 12 and displaying set temperature, air flow setting, setting mode, and the like.

  The air conditioner ECU 14 includes an outside air temperature sensor 22 that detects the outside air temperature of the vehicle 12, a solar radiation amount sensor 24 that detects the amount of solar radiation, a cooling water temperature sensor 26 that detects the temperature of the cooling water supplied from the engine 18, and the vehicle. A vehicle interior temperature sensor 28 for detecting the vehicle interior temperature 12 and a vehicle interior humidity sensor 30 for detecting the vehicle interior humidity of the vehicle 12 are connected. Note that a window glass temperature sensor 21 that directly detects the vehicle interior surface temperature of the window glass may be connected to the air conditioner ECU 14 as necessary.

  Further, the air conditioner ECU 14 is connected to an outside / inside air switching damper driving unit 32, a blower driving unit 34, an air mix damper driving unit 36, and a mode switching damper driving unit 38 that constitute the air conditioning unit 16.

  The air conditioner unit 16 has an outside air intake port 40 that takes in outside air or inside air, and air outlets 42, 44, and 46 for supplying air adjusted in temperature, humidity, and air flow rate to a predetermined part in the vehicle interior. A duct 48 is provided. An outside / inside air switching damper 50 that is driven by the outside / inside air switching damper driving unit 32 and switches between outside air and inside air is disposed in the outside / inside air intake port 40. Mode switching dampers 52 and 54 that are driven by a mode switching damper drive unit 38 and that switch between the outlets 42, 44, and 46 on the defroster side, the face side, and the foot side in the passenger compartment are arranged at the outlets 42, 44, and 46, respectively. Established.

  Inside the duct 48, a blower 56 driven by the blower drive unit 34 is disposed in the vicinity of the outside air intake port 40. An evaporator 58 that cools and dehumidifies the blown air is disposed on the downstream side of the air blown by the blower 56 and in the internal intermediate portion of the duct 48. A heater 60 that heats the air that has passed through the evaporator 58 with cooling water supplied from the engine 18 is disposed between the evaporator 58 and the outlets 42, 44, and 46. In this case, an air mix damper 62 that is driven by the air mix damper driving unit 36 and adjusts the supply amount of the air that has passed through the evaporator 58 to the heater 60 is disposed between the evaporator 58 and the heater 60. Is done.

  On the air outlet side of the evaporator 58, an evaporator outlet temperature detection sensor 66 for detecting the evaporator outlet temperature of air is disposed. The evaporator outlet temperature detection sensor 66 is connected to the air conditioner ECU 14.

  The air conditioner unit 16 is driven by the rotational force of the engine 18 to compress the refrigerant 68, the condenser 70 that condenses the refrigerant compressed by the compressor 68, and the refrigerant condensed by the condenser 70. A gas-liquid separator 72 that separates the liquid component and the gas component and an expansion valve 74 that expands the gas component of the refrigerant separated by the gas-liquid separator 72 and supplies the expanded gas component to the evaporator 58 are provided. Note that the refrigerant supplied to the evaporator 58 is circulated and supplied to the compressor 68. In the case of the variable capacity type, the compressor 68 is connected to the air conditioner ECU 14, and the capacity thereof is controlled by the air conditioner ECU 14. When the compressor 68 is a fixed capacity type, a clutch control unit 71 that controls a clutch 69 that connects and disconnects the engine and the compressor 68 is connected to the air conditioner ECU 14, and the compressor 68 is controlled via the clutch control unit 71. The

  The vehicle air conditioner 10 according to the present embodiment is basically configured as described above. Next, the operation thereof will be described with reference to the flowchart shown in FIG.

  When an occupant of the vehicle 12 operates the operation display unit 20 to turn on the power supply of the vehicle air conditioner 10 and then performs setting of a desired air flow rate and temperature, mode setting, etc., the air conditioner ECU 14 Each sensor information is read from the outside air temperature sensor 22, the solar radiation amount sensor 24, the cooling water temperature sensor 26, the vehicle interior temperature sensor 28, the vehicle interior humidity sensor 30, and the evaporator outlet temperature detection sensor 66 (step S1).

  Therefore, the air conditioner ECU 14 first acquires the window glass dew point vehicle interior absolute humidity Xrmax, which is the limit vehicle interior absolute humidity at which the window glass interior surface does not condense (step S2).

  In this case, the window glass interior surface temperature Tg during traveling of the vehicle 12 can be regarded as substantially equal to the outside air temperature Tam. Therefore, the window glass dew point vehicle interior absolute humidity Xrmax is obtained from the outside air temperature Tam (= Tg) detected by the outside air temperature sensor 22 using the wet air diagram shown in FIG. The window glass temperature sensor 21 may be disposed on the surface of the vehicle interior of the window glass, and the window glass dew point vehicle interior absolute humidity Xrmax may be obtained using the directly detected window glass vehicle interior surface temperature Tg.

  Here, the wet air diagram represents a relationship between physical conditions such as air temperature (° C.), absolute humidity (kg / kg), relative humidity (%), and enthalpy of the air. The window window dew point cabin absolute humidity Xrmax may be expressed by a polynomial expression of the relationship between the air temperature and the absolute humidity when the relative humidity is 100%, and may be obtained by calculation using the outside air temperature Tam (= Tg) as a variable. The relationship may be stored as a look-up table in the memory 23 of the air conditioner ECU 14, and may be obtained as the window glass dew point vehicle interior absolute humidity Xrmax corresponding to the acquired outside air temperature Tam or the window glass vehicle interior surface temperature Tg.

  Next, the vehicle interior set absolute humidity Xset within a range where the window glass does not condense and the vehicle interior feels comfortable is obtained (steps S3 to S6).

  Therefore, the air conditioner ECU 14 uses the vehicle interior set temperature Tset that is set by the occupant using the operation display unit 20 and the vehicle interior upper limit relative humidity that are set in advance from the wet air diagram shown in FIG. The vehicle interior set absolute humidity (temporary Xset) is obtained (step S3). Note that the vehicle interior upper limit relative humidity can be set to, for example, approximately 60%, which is the upper limit relative humidity that humans feel comfortable. The passenger compartment upper limit relative humidity may be set arbitrarily by the occupant by providing a setting unit in the operation display unit 20, for example.

  In this case, the relationship between the two variables of air temperature and relative humidity and the absolute humidity is expressed by a polynomial, and the provisional vehicle interior set absolute humidity (provisional Xset) is calculated by using the vehicle interior set temperature Tset and the vehicle interior upper limit relative humidity as variables. This relationship may be obtained, and this relationship is stored as a lookup table in the memory 23 of the air conditioner ECU 14 for each relative humidity, and the provisional vehicle interior set absolute humidity (temporary Xset) is obtained from the lookup table for the selected relative humidity. You may do it.

  Next, the window glass dew point vehicle interior absolute humidity Xrmax is compared with the temporary vehicle interior set absolute humidity (temporary Xset) (step S4). In this case, if Xrmax> temporary Xset, even if the air in the temporary vehicle cabin set absolute humidity (temporary Xset) is cooled in the vicinity of the window glass, the air does not exceed 100% relative humidity. The glass will not fog up. In addition, the humidity in the passenger compartment is within a range where comfort is felt. On the other hand, if Xrmax ≦ temporary Xset, the air in the provisional vehicle interior set absolute humidity (temporary Xset) is cooled in the vicinity of the window glass, and the air exceeds 100% relative humidity. It will occur.

  Therefore, when Xrmax> temporary Xset, Xset = temporary Xset is set (step S5), and when Xrmax ≦ temporary Xset, Xset = Xrmax is set (step S6). By setting the vehicle interior setting absolute humidity Xset in this way, the cooling capacity of the compressor 68 is minimized, the window glass is not fogged, and the vehicle interior can be made comfortable humidity. .

  Next, the required air temperature Tao and the required air outlet absolute humidity Xao from the air outlet 42, 44 or 46 necessary to realize the vehicle interior set temperature Tset and the vehicle interior set absolute humidity Xset are calculated (step S7). .

The required air temperature Tao is detected by the passenger compartment set temperature Tset set by the passenger, the passenger compartment temperature Tr detected by the passenger compartment temperature sensor 28, the outdoor air temperature Tam detected by the outdoor air temperature sensor 22, and the solar radiation sensor 24. Using the amount of solar radiation Ts
Tao = Ktset / Tset / Ktr / Tr-Ktam / Tam
−Kts · Ts−Ct (1)
Ktset: Car interior set temperature coefficient
Ktr: Vehicle interior temperature sensor coefficient
Ktam: outside temperature sensor coefficient
Kts: Solar radiation sensor coefficient
Ct: calculated as a temperature calculation coefficient.

Further, the required absolute humidity Xao of the blown air is assumed that the outside air temperature Tam and the outside air humidity are approximately proportional, and the vehicle interior set absolute humidity Xset obtained in step S5 or S6 and the vehicle interior detected by the vehicle interior humidity sensor 30 are used. Using the absolute humidity Xr and the outside air temperature Tam detected by the outside air temperature sensor 22,
Xao = Kxset, Xset-Kxr, Xr-Kxam, Tam-Cx1
... (2)
Kxset: Car interior setting absolute humidity coefficient
Kxr: Absolute humidity coefficient in the passenger compartment
Kxam: outside air absolute humidity coefficient
Cx1: calculated as a humidity calculation coefficient. When the vehicle interior humidity sensor 30 is a sensor that detects relative humidity, the vehicle interior temperature sensor 28 detects the vehicle interior temperature Tr and the vehicle interior humidity sensor 30 detects the relative humidity. The vehicle interior absolute humidity Xr can be obtained from the wet air diagram shown.

  Using the blown air required temperature Tao and the blown air required absolute humidity Xao calculated as described above, the control temperature Tea that can minimize the operating rate of the compressor 68 is calculated.

  When the compressor 68 is a fixed capacity type and is connected to the engine 18 via the clutch 69, the detected value of the evaporator outlet temperature detection sensor 66 when the compressor 68 is disconnected from the engine 18 is used as the control temperature Tea. The detected value of the evaporator outlet temperature detection sensor 66 when the compressor 68 is connected to the engine 18 is controlled to the control temperature Tea + ε (ε: constant). When the compressor 68 is a variable capacity type, the detected value of the evaporator outlet temperature detection sensor 66 is controlled to the control temperature Tea.

  The window window dew point vehicle interior absolute humidity Xrmax obtained in step S2 is compared with the vehicle interior absolute humidity Xr detected by the vehicle interior humidity sensor 30, and if Xrmax ≦ Xr (step S8), the air in the vehicle interior is the window glass. If it is cooled in the vicinity of the window, fogging may occur in the window glass. Therefore, in order to maximize the dehumidifying capacity of the evaporator 58, the control temperature Tea is set to the lower limit temperature min at which the evaporator 58 is not frosted (step S9).

  On the other hand, if Xrmax> Xr (step S8), even if the air in the passenger compartment is cooled in the vicinity of the window glass, the air does not exceed 100% relative humidity, so the window glass does not fog up. . Therefore, when (Tset−δ)> Tr (step S10) and (Xset−γ)> Xr (step S11) where δ is a margin with respect to temperature and γ is a margin with respect to humidity, in the current state, no more. Therefore, there is no need for further dehumidification, and there is no need for further cooling. Therefore, Tea = β (for example, about 20 ° C.) is set in order to minimize the driving state of the compressor 68 (step 20 ° C.). S12).

  If Xrmax> Xr (step S8), (Tset−δ) ≦ Tr (step S10), and (Xset−γ)> Xr (step S13), it is determined that cooling is necessary. . At this time, the margin for the necessary air temperature Tao is set as α, and Tea = Tao−α is set (step S14).

  If Xrmax> Xr (step S8), (Tset−δ)> Tr (step S10), and (Xset−γ) ≦ Xr (step S11), it is determined that dehumidification is necessary. . At this time, Ta = T (Xao) −η is set, where T (Xao) is the temperature at which the required absolute humidity Xao for the blown air is 100% relative humidity, and η is the calculation coefficient of the temperature T (Xao) (step S15). .

  Furthermore, if Xrmax> Xr (step S8), (Tset−δ) ≦ Tr (step S10), and (Xset−γ) ≦ Xr (step S13), it is determined that cooling and dehumidification are necessary. Is done. At this time, Tao-α and T (Xao) -η are compared (step S16), and the smaller one is set as the control temperature Tea (steps S14 and S15).

  As described above, after the control temperature Tea is set, when the compressor 68 is a variable capacity type, the capacity is adjusted (step S17). The air conditioner ECU 14 calculates the opening degree of the air mix damper 62 (step S18), and drives the air mix damper driving unit 36 to adjust the opening degree of the air mix damper 62. Further, the air conditioner ECU 14 calculates a voltage to be supplied to the blower drive unit 34 so that the amount of air blown by the blower 56 becomes a necessary amount (step S19), and drives the blower drive unit 34 with the voltage. Furthermore, the air conditioner ECU 14 calculates the position of the mode switching damper 52 or 54 according to the mode set by the operation display unit 20 (step S20), drives the mode switching damper drive unit 38, and sets the mode switching damper 52 or 54. Change over.

  By driving the air conditioner unit 16 in the above state, air conditioning control is performed so that the temperature in the vehicle interior becomes the vehicle interior set temperature Tset and the humidity becomes the vehicle interior set absolute humidity Xset. In this case, the vehicle interior is adjusted so that the window glass is not fogged and the upper limit of the comfortable humidity is not exceeded. Moreover, since the compressor 68 is controlled by the minimum necessary driving force capable of maintaining this state, energy consumption by the compressor 68 can be saved.

  Fig. 5 ignores the Kxma / Tam term in equation (2) under conditions where the humidity of the outside air is normal humidity (for example, 50%), the vehicle interior set temperature Tset is 25 ° C, and the vehicle interior upper limit relative humidity is 60%. In this embodiment, the control temperature Tea is calculated and the control temperature Tea is calculated based on the relationship of the formula (2) in the case of the prior art in which the air conditioner unit 16 is controlled (dotted line). The case (solid line) shows the result of comparing the energy consumption per unit time of the compressor 68 with respect to the outside air temperature Tam. According to this embodiment, it is understood that the power saving of the compressor 68 can be achieved with respect to the prior art.

It is explanatory drawing of the vehicle carrying the vehicle air conditioner of this embodiment. It is a block diagram of the vehicle air conditioner of this embodiment. It is a process flowchart in the vehicle air conditioner of this embodiment. It is a wet air diagram. It is explanatory drawing which compared the energy consumption per unit time of the compressor with respect to the external temperature by this embodiment with the conventional energy consumption.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vehicle air conditioner 12 ... Vehicle 14 ... Air-conditioner ECU 16 ... Air-conditioner unit 18 ... Engine 20 ... Operation display part 22 ... Outside temperature sensor 24 ... Solar radiation sensor 26 ... Coolant temperature sensor 28 ... Vehicle interior temperature sensor 30 ... Car Indoor humidity sensor 56 ... Blower 58 ... Evaporator 60 ... Heater 66 ... Evaporator outlet temperature detection sensor 68 ... Compressor 70 ... Condenser 72 ... Gas-liquid separator 74 ... Expansion valve

Claims (3)

Heating means for heating air;
Cooling means for cooling the air;
A window glass vehicle interior surface temperature acquisition means for acquiring a window glass vehicle interior surface temperature Tg;
Window glass dew point vehicle interior absolute humidity obtaining means for obtaining window glass dew point vehicle interior absolute humidity Xrmax with the window glass vehicle interior surface temperature Tg as a dew point;
Provisional vehicle interior setting absolute humidity acquisition means for acquiring provisional vehicle interior setting absolute humidity (provisional Xset) relative to the vehicle interior allowable upper limit relative humidity at the vehicle interior setting temperature Tset;
If Xrmax> temporary Xset, then Xset = temporary Xset, and if Xrmax ≦ temporary Xset, if Xset = Xrmax, vehicle interior setting absolute humidity setting means for setting vehicle interior setting absolute humidity Xset;
Vehicle interior absolute humidity acquisition means for acquiring vehicle interior absolute humidity Xr;
The required air temperature Tao required for obtaining the vehicle interior set temperature Tset is:
Tao = Ktset / Tset / Ktr / Tr-Ktam / Tam
-Kts ・ Ts-Ct
Ktset: Car interior set temperature coefficient
Ktr: Vehicle interior temperature sensor coefficient
Ktam: outside temperature sensor coefficient
Kts: Solar radiation sensor coefficient
Ct: Temperature calculation coefficient
Tr: Interior temperature
Tam: outside air temperature
Ts: means for calculating required air temperature for calculating the amount of solar radiation;
Blowing air required absolute humidity Xao necessary to obtain the vehicle interior setting absolute humidity Xset,
Xao = Kxset, Xset-Kxr, Xr-Kxam, Tam-Cx1
Kxset: Car interior setting absolute humidity coefficient
Kxr: Absolute humidity coefficient in the passenger compartment
Kxam: outside air absolute humidity coefficient
Cx1: means for calculating required absolute humidity of blown air to be calculated as a humidity calculation coefficient;
Control temperature calculating means for calculating a control temperature Tea of the air cooled by the cooling means based on the required air temperature Tao and the required absolute air humidity Xao;
Cooling control means for controlling the cooling capacity based on the control temperature Tea;
Heating control means for controlling the heating capacity based on the control temperature Tea;
A vehicle air conditioner comprising: The apparatus of claim 1.
The control temperature calculation means includes
If Xrmax ≦ Xr, Tea = min (min: lower limit temperature at which the cooling means does not frost),
If Xrmax> Xr, (Tset−δ) ≦ Tr (δ: predetermined margin), and (Xset−γ)> Xr (γ: predetermined margin), Tea = Tao−α (α: constant),
If Xrmax> Xr, (Tset−δ)> Tr, and (Xset−γ) ≦ Xr, Tea = T (Xao) −η (η: arithmetic coefficient, T (Xao): relative humidity 100% At the temperature at which the blown air needs absolute humidity Xao)
If Xrmax> Xr, (Tset−δ) ≦ Tr, and (Xset−γ) ≦ Xr, Tea = Tao−α or Tea = T (Xao) −η, whichever is smaller,
If Xrmax> Xr, (Tset−δ)> Tr, and (Xset−γ)> Xr, Tea = β (β: constant)
The control temperature Tea is calculated as follows. The apparatus of claim 1.
A vehicle air conditioner comprising a vehicle interior humidity sensor for detecting the vehicle interior absolute humidity Xr.

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