JPH05345515A - Vehicle air conditioner - Google Patents

Abstract

PURPOSE:To provide a vehicle air conditioner which prevents a window glass plate from being clouded up when dehumidifying performance is insufficient because of preset low cooling performance at the time of low temperature and high humidity, for example, on a rainy day. CONSTITUTION:The glass surface temperature of window glass is estimatively- calculated from the information obtained from various types of sensors such as an outside air temperature sensor 41, a cabin temperature sensor 42, a solar radiation sensor 43 to calculate a target blow-out air humidity which does not cloud up the window glass and a dew-point temperature relative to the humidity. For operating the air conditioner with cooling performance (dewing prevention performance) required by this condition, dehumidifying performance which does not cloud up the window glass is obtained. Even if the cooling performance (temperature condition performance) calculated from a preset temperature and various types of sensors is lower than the dewing prevention capacity, no clouding is generated on the window glass by operating a cooling machine with the dewing prevention capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner, and more particularly to an air conditioner for controlling the temperature inside a vehicle by adjusting the temperature of blown air using a cooling means and a heating means.

[0002]

2. Description of the Related Art A vehicle air conditioner takes in air from inside or outside the room, or both, adjusts the temperature and humidity of the air taken in by a cooler or a heater, and blows this air into the passenger compartment. It controls the room temperature and humidity. The cooler uses a so-called cooling cycle that uses the heat of vaporization of the refrigerant gas, but the compressor conventionally used in this cooling cycle has a constant discharge capacity. When such a compressor with a constant discharge capacity is used in a vehicle air conditioner, the cooling capacity cannot be adjusted, and the compressor is cooled to the maximum at full load, while the air that has been cooled once is required for the heater thereafter. The temperature is controlled by heating it to a certain temperature, or the indoor temperature is controlled by turning on and off the compressor, which is a repetition of full load and no load.

In the former case, the power of the compressor is increased more than necessary by wasting the energy of cooling and heating more than necessary. In the latter case, turn on the compressor
Due to the repetition of turning off, the indoor temperature repeatedly rises and falls around the set temperature and gives an occupant an uncomfortable feeling.

In order to solve this problem, a variable capacity compressor capable of changing the discharge capacity has been developed, and an air conditioner using the same is disclosed in Japanese Patent Publication No. 1-333364.
It is shown in the publication. In this air conditioner, the capacity of the compressor is adjusted by changing the capacity of the compressor in accordance with the target temperature, which is the temperature of the blown air required to bring the vehicle interior temperature to the set value, and the heating is performed. The heating capacity of the vessel is also adjusted to control the desired temperature. That is, when the target temperature is low, the capacity of the cooler is increased, and as the target temperature rises, the capacity of the cooler is decreased and the capacity of the heater is increased to control the temperature.

[0005]

However, in the device disclosed in the above publication, when the air temperature is low, the capacity of the cooler is controlled to be low, the refrigerant temperature becomes high, and the dehumidifying action is reduced. When the temperature is low and the humidity is high, the dehumidifying action is reduced as described above, so that the humidity in the passenger compartment may not be lowered and dew may be condensed on the window glass or the like. Such a low temperature and high humidity is likely to occur in rainy weather. In rainy weather, windows are often closed to prevent raindrops from blowing in, which also causes an increase in vehicle interior humidity.

As described above, according to the conventional apparatus, in the case of rainy weather where the required cooling capacity is low and the required dehumidifying action is high, the window glass may be fogged due to insufficient dehumidification. There was a problem.

The present invention has been made in order to solve the above problems, and not only eliminates the discomfort of the occupant but also maintains a sufficient dehumidifying action even when the required cooling capacity is low such as in the case of rain. , The window glass is not fogged, and more than necessary cooling is suppressed to save energy.

[0008]

In order to achieve the above-mentioned object, a vehicle air conditioner according to the present invention comprises a heating means capable of controlling a heating capacity, a cooling means capable of controlling a cooling capacity, and an outside air. Based on information from at least one of the temperature sensor, vehicle interior temperature sensor, and solar radiation sensor,
Target temperature calculating means for calculating a target value of the blown-air temperature to control the vehicle interior temperature to a preset temperature, and a glass surface for estimating the temperature of the window glass from the outside air temperature sensor and the vehicle interior temperature sensor A temperature calculating means, and a blowing air required temperature calculating means for calculating the humidity of the blowing air required based on the humidity whose dew point is the estimated glass surface temperature, and calculating the dew point temperature of the air having the calculated humidity. , Comparing the target temperature and the required temperature of the blown air,
Control temperature calculation means for setting the lower temperature as the control temperature, cooling control means for controlling the cooling capacity based on the control temperature, and heating control for controlling the heating capacity based on the control temperature and the target temperature. Have means.

[0009]

In the vehicular air conditioner of the present invention, the surface temperature of the window glass is estimated by various sensors, and the humidity of the blown-out air is calculated so that the humidity in the vehicle interior does not cause dew condensation at this glass surface temperature. The dew point temperature in the air showing the calculated humidity is calculated. The cooler is controlled with the lower of the target temperature of the blown air required to control the vehicle interior temperature to the set temperature and the above-mentioned dew point temperature as the cooler control temperature, and cool down to a temperature below that. There is no.

In other words, the above-mentioned dew point temperature is the upper limit of the target temperature for obtaining the dehumidifying ability so that the window glass does not become fogged, and when the cooler is operated at a target temperature exceeding this, sufficient dehumidifying ability is obtained. I can't. For example, if the target temperature of the blown air is equal to or higher than the above dew point temperature, the absolute humidity at the time of saturation of this air is higher than the absolute humidity of the air at the dew point temperature, and therefore the vehicle controlled by the blown air of each of these conditions is controlled. The indoor humidity also becomes higher when controlled at a target temperature higher than the dew point temperature, and the saturation amount exceeds the window glass surface. Since the air blown out is not always close to the saturated vapor pressure, the window glass may not always fog even if the control is performed based on the target temperature above the dew point temperature, but it is controlled at least at the target temperature below the dew point temperature. No condensation will occur. Moreover, the compressor operates with less than full load.

Under the condition that the window glass may be fogged, the window is prevented from being fogged by cooling it to the calculated value of the dew point temperature of the blown air obtained from the calculated glass surface temperature. Is not cooled down to the full load of
Reduce the load on the compressor. In this case, the cooled air can be partially heated by a heater to bring the room temperature to the set temperature. Thereby, the window glass is not fogged and energy saving can be achieved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a vehicle air conditioner of this embodiment. This embodiment is an example used in an automobile which is powered by an internal combustion engine, in which a heater using cooling water of the internal combustion engine is used as the heating means, and a variable displacement compressor driven by the engine is used as the cooling means. A cooler is used that performs a refrigeration cycle by compressing a refrigerant and expanding / vaporizing the refrigerant.

The vehicle air conditioner of this embodiment is provided with a ventilation duct 10, a fan 11, an electric motor 12, inside / outside air switching dampers 13 and 14, and actuators 15 and 16.
And outlet switching dampers 17 and 18, vehicle interior air intakes 21 and 22, outside air intakes 23 and 24, vent outlets 25, heater outlets 26, defroster outlets 27, and heater cores 30. , Air mix damper 31
An evaporator 32, a condenser 33, a variable capacity compressor 34, an expansion valve 35,
The fan speed control device 36, the air mix damper / actuator 37, the control device 40, and the outside air temperature sensor 4
1, a vehicle interior temperature sensor 42, a solar radiation sensor 43, a condenser pressure sensor 45, and an evaporator pressure sensor 46.
, Compressor intake temperature sensor 47, and rotation sensor 4
8 and a temperature setting device 49.

Next, the operation will be described. In the vehicle air conditioner configured as described above, the ventilation duct 10
Has air intakes 21, 22, 23, 24 at one end,
The fan 11 is arranged immediately after the air intake ports 21, 22, 23, 24, and the air outlet ports 25, 2 at the other end are arranged.
The air is blown toward 6, 27. Fan 11 is electric motor 1
The rotation speed of the electric motor 12 is controlled by the fan speed control device 36 which receives a command from the control device 40. In this case, the fan speed control device 36 may be composed of a transistor, and at that time, the fan speed is duty controlled.

The air intake ports 21, 22, 23, 24
Is a vehicle interior air intake port 21 for taking in air from the vehicle interior,
22 and outside air intakes 23 and 24 for taking in the outside air. By switching the air intakes 21, 22 and 23, 24 by the inside and outside air switching dampers 13, 14, the air intake in the vehicle interior or the outside air intake is performed. Can be turned on. Also, the air intake ports 21, 22, 23, 2
4 shows that the inside / outside air switching damper 13 opens the air intake port 21 and closes the air intake port 23, and the inside / outside air switching damper 14 opens the air intake port 24 and closes the air intake port 22 so that the air inside the vehicle and the outside air are closed. You can incorporate both. That is, the inside and outside air can be mixed.

The inside / outside air switching dampers 13 and 14 are moved by actuators 15 and 16 based on a command from the control device 40. An evaporator 32, which is a heat exchanger for cooling, is arranged downstream of the fan 11 over the entire cross section of the ventilation duct 10 to cool the passing air.
Furthermore, a heater core 30 which is a heat exchanger for heating is provided downstream.
Are arranged so as to occupy a part of the cross section of the ventilation duct 10, and the air mix damper 31 is provided at one end of the heater core 30.
The rotating shaft of is arranged, and by changing the rotation angle of the air mix damper 31, it is possible to change the ratio of the air flowing through the ventilation duct 10 between the air passing through the heater core 30 and the air bypassing it. The current angle with respect to the maximum rotation angle of the air mix damper 31 is called the opening of the air mix damper 31 (when the heater core 30 is fully closed, it is called opening 0). The blown air temperature can also be changed by changing the opening.
The air mix damper 31 is operated by an air mix damper actuator 37 based on a command from the control device 40.

Further, on the downstream side, a vent outlet 25 is provided.
, A heater outlet 26, and a defroster outlet 27. The vent outlet 25 blows mainly toward the upper half of the occupant, the heater outlet 26 blows mainly toward the occupant's feet, and the defroster outlet. 27 blows toward the front window. Vent outlet 25 and defroster outlet 2
7 is switched by the switching damper 17, and the heater outlet 26 is switched by the switching damper 18. Then, the evaporator 32, the capacitor 33,
A refrigeration cycle is constituted by the compressor 34 and the expansion valve 35. In addition, compressor 3
Reference numeral 4 is a variable capacity compressor.

That is, a wobble plate may be provided on the drive shaft, and the piston stroke may be changed by freely changing the inclination angle of the wobble plate to control the discharge amount. Of course, another structure may be used.

Next, the control device 40 controls the outside air temperature sensor 4
1, the outside air temperature To detected by 1, the vehicle interior temperature Tr detected by the vehicle interior temperature sensor 42, the solar radiation amount ST detected by the solar radiation sensor 43, and the set temperature Tse from the temperature setting device 49.
t is input, and the target blown air temperature Tao required to bring the vehicle interior temperature to the set temperature Tset is obtained from the information by the equation (1).

Tao = k1 * Tset-k2 * Tr-k3 * To-k4 * ST + c1 (1) Where, Tset ... Set temperature from temperature setting device 49 Tr ... Vehicle interior temperature sensor 42 The temperature inside the vehicle detected by To: the outside air temperature detected by the outside air temperature sensor 41 ST: the amount of solar radiation k1, k2, k3, k4, c1 detected by the solar radiation sensor 43 is a constant.

Next, Tg of the glass surface temperature of the window glass is calculated by the equation (2).

Tg = k5 · To + k6 · Tr + k7 · ST (2) k5, k6, and k7 are constants, or the reason why clouding of the window glass is a problem is when the sunlight is weak such as in rainy weather. It may be calculated in ′).

Tg = k5 ′ · To + k6 ′ · Tr (2 ′) k5 ′ and k6 ′ are constants Note that each constant depends on the volume of the passenger compartment, the arrangement of outlets, the capacity of the cooler and the heater, etc. It is desirable to set it for each vehicle type. Further, it may be changed depending on the vehicle speed or the wind speed of the blown air. That is, it may be changed as a function of the vehicle speed or the wind speed of the blown air.

The absolute humidity Xg with the calculated glass surface temperature Tg as the dew point is determined by the equation (3). If the absolute humidity in the vehicle compartment is less than Xg, the glass surface will not be fogged. Therefore, if Xg-ΔXg is set as the target humidity in the vehicle interior with a margin, the target air humidity for making the target humidity Xg-ΔXg in the vehicle interior. (Absolute humidity) Xao can be calculated by the equation (4). Formula (4) is a calculation formula that is applied when a vehicle interior humidity sensor is installed and feedback is performed using the vehicle interior humidity. However, if feedback is not possible because there is no vehicle interior humidity sensor, the target blown air The humidity Xao is calculated by the equation (5). Xg = F1 (Tg) (3) Here, F (x) is a function. Xao = kh1.Xrset-kh2 (Xr-Xrset) + c2 (4) Where, Xrset ... target humidity in the vehicle Xr .... humidity in the vehicle detected by a vehicle humidity sensor kh1, kh2, c2 Is a constant. Xao = kh1.Xrset + c3 (5) Here, kh1 and c3 are constants.

It should be noted that either of the equations (4) and (5) may be used to calculate the target blown air humidity Xao, but if the equation (4) is used, the control accuracy is improved but a vehicle interior humidity sensor is required. On the contrary, if the formula (5) is used, the control accuracy is deteriorated, but there is an advantage that the vehicle interior humidity sensor is unnecessary.

Next, the dew point temperature Td of the air having the target outlet air humidity Xao obtained from the absolute humidity Xg is obtained by the equation (6). Then, the dew point temperature Td and the target blown air temperature Ta
If o is compared and the smaller one is the air after passing through the evaporator, the window will not fog. That is, if the temperature of the air after passing through the evaporator is Tea, then Tea can be expressed by equation (7).
It asks in.

That is, if the cooler is operated so that the air temperature after passing through the evaporator is equal to or lower than Tea, it is possible to obtain a sufficient dehumidifying capacity to set the target outlet humidity to Xao.
Therefore, the humidity in the room becomes Xrset or less, and the glass is not clouded.

Next, the air temperature after passing through the evaporator is T
The evaporator refrigerant temperature Ter which becomes ea is obtained by the equation (8). Then, the refrigerant pressure Peset of the evaporator at which the refrigerant temperature of the evaporator becomes Ter is obtained by the equation (9). This is the evaporator target refrigerant pressure Pese.
t. In the equation (10), the function F2 (x) is obtained from the relationship between the refrigerant pressure and the evaporation temperature.

Td = g (Xao) (6) Here, g (x) is a function, and g (x) = F1 ^-1 (x). F1 ^-1 (x) is an inverse function. kh1, kh2, c2
Is a constant. If Tao ≧ Td, Tea = Td (7) If Tao <Td, Tea = Tao Ter = Tea−Δtea (8) Here, Δtea is a constant value. Peset = F2 (Ter) (9) Next, Pi of FIG. 2 showing the relationship between the refrigerant pressure and the enthalpy
Determine the enthalpy i4 at point IV from the diagram. Since the enthalpy i4 at point IV is equal to the enthalpy at point III, equation (10)
Determined by.

I4 = FL (Pc) −C · ΔTc (10) where Pc ·· the capacitor pressure FL (x) detected by the capacitor pressure sensor 45 ··· the relational expression between the enthalpy of the saturated liquid line and the pressure c · … Specific heat of refrigerant liquid ΔTc ··· is a subcool, for example, 5 ° C (constant). Next, the enthalpy i1 of the refrigerant sucked into the compressor (point I in the Pi diagram) is calculated by equation (11). .. In the equation (11), the evaporator refrigerant temperature Ter is obtained from the equation (8). Alternatively, it may be obtained by the equation (12).

I1 = FV (Petset) + Cpr · Δter (11) Here, Δter = Te−Ter. Further, Te: Compressor intake refrigerant temperature detected by the compressor intake refrigerant temperature FV (x) ... Relational expression between enthalpy and pressure of saturated vapor line Cpr ... Constant heat specific heat of refrigerant Δter ... Compressor Superheat of suction refrigerant Ter = G2 (Petset) (12) where G2 (x) = F2 ^-1 (x). G2 (x)
Is a function, and the relational expression between the pressure of the refrigerant and the evaporation temperature F2 ^-1 (x)
Is the inverse function of F2 (x). Therefore, the cooling capacity viewed from the refrigerant side is expressed by the equation (13). Qr = G (i1−i4) (13) Here, G is the refrigerant discharge amount.

On the other hand, the cooling capacity viewed from the air side is obtained as follows. That is, first, the enthalpy of the intake air is calculated.In this case, if the air intake is the outside air intake, the enthalpy of the outside air is calculated. Is calculated from the inside / outside air mixing ratio. Therefore, the enthalpy of the air outside the vehicle compartment can be calculated by the equation (14), and the enthalpy of the air inside the vehicle compartment can be calculated by the equation (15). Expression (1
4) and (15), Xo (absolute humidity of outside air), Xr
(Absolute humidity in the passenger compartment) may be obtained by installing a humidity sensor inside or outside the passenger compartment, or by setting the relative humidity inside or outside the passenger compartment to a constant value, for example, 50%, and obtaining the absolute humidity at that time. Good. The enthalpy in the case of mixing the inside and outside air is given by equation (16).
Ask by.

If = Cpa · To + (Cwv · To + L) · Xo (14) ir = Cpa · Tr + (Cwv · Tr + L) · Xr (15) where L · ·· Evaporation latent heat of water Xo ... Absolute humidity of outside air Xr ... Absolute humidity of passenger compartment Cpa ...- Constant pressure specific heat of air Cwv ... ... Constant pressure specific heat of water vapor ifr = ir x Rm / 100 + if x (100-Rm ) / 100 (16) Here, Rm is the mixing ratio of the vehicle interior air.

Next, the enthalpy iea of the air after passing through the evaporator is calculated by the equation (17). In the equation (17), the temperature Tea of the air after passing through the evaporator is obtained by the equation (18) as described above. In Expression (17), the absolute humidity Xea of the air after passing through the evaporator is obtained by Expression (19). In equation (19), the target blown air temperature Ta
Absolute humidity Xd with o as the dew point is Xd = F1 (Tao)
The absolute humidity Xea of the air after passing through the evaporator is calculated with the absolute humidity of the intake air as Xs.

Iea = Cpa · Tea + (Cwv · Tea + L) · Xea (17) If Tao ≧ Td, then Tea = Td (18) If Tao <Td, then Tea = Tao Tao ≧ Td, Xea = Xao (19) ) In Tao <Td, if Xs ≧ Xd, then Xea = Xd If Xs <Xd, then Xea = Xs, where Xs is Xs = Xr if the air intake is the vehicle interior air intake, Xs = Xo if the outside air intake is internal / external air mixture Xs = (Xr * Rm) / 100 + {Xo * (100-Rm) / 100} Next, the air volume of the air conditioner, that is, the air volume passing through the evaporator is obtained. In many cases, the air flow rate of the air conditioner uniquely determines the voltage applied to the blower motor by the target blown air temperature Tao. As an example, the case of the first embodiment will be described. First, the correspondence between the target blown air temperature Tao and the applied voltage is shown in FIG. The correspondence between the applied voltage and the air volume of the air conditioner is shown in FIG. Therefore, the value of the applied voltage for a specific value of the target blown air temperature Tao is obtained from FIG. 3, and the value of the air volume of the air conditioner corresponding to the value of the applied voltage is obtained from FIG. 4 to determine the air volume of the air conditioner. Make a decision.

Thus, the cooling capacity viewed from the air side is required. This is shown in equation (20). Since the cooling capacity viewed from the air side is equal to the cooling capacity viewed from the refrigerant side, equation (21)
Holds, and equation (22) is derived from equation (21). Substituting equations (10) and (11) into i1 and i4 of equation (23),
Equation (23) is obtained. Based on the refrigerant discharge amount G obtained by the equation (23), the variable capacity compressor capacity Vc can be obtained by the equation (24). In the equation (24), V11 is the specific volume when the refrigerant is sucked in by the compressor, and can be obtained by the equation (25). Further, ηv in the equation (24) is the volumetric efficiency, and
It can be obtained by 6). N in equation (26)
c is the compressor rotation speed, which may be detected by adding a rotation sensor to the compressor, or may be calculated from the engine rotation speed.

(Is-iea) × V × Υa (20) where is ... Enthalpy of intake air is = ir for vehicle interior air, is = if for outside air, and is = ifr for inside / outside air mixing. .. V ・ ・ ・ ・ Air volume Vr for cabin air, Vf for outside air, V for mixed inside and outside air
fr. (See FIG. 4) Υa ... Specific weight of air G (i1−i4) = (is-iea) × V × Υa ... (21) G = {(is-iea) · V · Υa} / (i1 -I4) (22) G = {(is-iea) .V. [Delta] a} / [FV (Petset) + Cp. [Delta] te- {FL (Pc) -C. [Delta] Tc}] (23) Vc = G / ( ηv × nc × v11) (24) V11 = R · Te / Petset (25) where R: Refrigerant gas constant T: 273 + Te Te: Compressor suction temperature sensor Compressor intake refrigerant temperature detected by ηv = f1 (nc, Pc / Peset) (26) where f1 (x) is a function.

Next, in the equation (24) for obtaining the displacement Vc of the variable displacement compressor, a feedback term for feedback when the compressor displacement control deviates from the target value and an error term considering the error are added to the equation (24). (27)
Is used to determine the capacity Vc of the variable capacity compressor.

Vc = {G / (ηv × nc × v11)}-K (Peset-Pe) + C (27) Where, Pe, ... Evaporator refrigerant pressure detected by the evaporator pressure sensor 46 Next, evaporator When the air temperature Tea after passing is equal to the target blown air temperature Tao, that is, Tao <Td
In such a case, the compressor capacity is controlled by the equation (24) to fully close the air mix damper 31 and the ventilation duct 1
All the air flowing through 0 flows so as to bypass the heater core 30.

On the other hand, when Tea = Td, that is, Ta
When o ≧ Td, it is necessary to set the blown air temperature to the target blown air temperature Tao and set the vehicle interior temperature Tr to the vehicle interior set temperature. Therefore, it is necessary to control the opening degree of the air mix damper 31 to raise the blown air temperature to the target blown air temperature Tao. In this case, in order to bring the blown-air temperature to the target blown-air temperature Tao, the mixing ratio Υam between the warm air heated by the heater core 30 by the air mix damper 31 and the cold air bypassing the heater core 30 is calculated by the equation (28). In Expression (28), Th may be detected by a sensor by the temperature of air immediately after the heater core, or may be obtained from Expression (29) from the engine coolant temperature. However, the cooling water temperature of the engine must be detected by a sensor.

Υam = (Tao−Td) / (Th−Td) (28) Here, the mixing ratio Υam is the ratio of warm air in the total air volume. Th = A · Tw + (1−A) Td (29) Here, Tw ... Engine cooling water temperature A ... Constant (0 ≦ A ≦ 1) The control device 40 controls the air mix damper 31. , Mixing ratio Υ
By controlling the value of am so that it has a value represented by the equation (28), the blown air temperature can be made the target blown air temperature Tao.

In the above embodiment, the superheat degree ΔTe of the compressor suction refrigerant is obtained by using the refrigerant temperature detected by the compressor suction temperature sensor 47. However, without using the compressor suction temperature sensor 47, the superheat degree of the compressor suction refrigerant is calculated. ΔTe may be set to be constant, for example, 10 ° C. A temperature sensor may be used as the condenser pressure sensor and the evaporator pressure sensor. This is because the evaporation temperature and pressure of the refrigerant can be converted to each other.

The air temperature after passing through the evaporator is T
The evaporator refrigerant temperature Ter, which is ea, is calculated by the equation (8) in the above embodiment, but the equation (30) or the equation (31) is used.
You may ask at.

Tea-Ter = Kv · V ^b (30) Tea-Ter = Kt · V ^d (Tr-Tao) (31) where Kv, b, Kt, d are constants.

Further, in the above embodiment, when the capacity of the variable capacity compressor 34 is set to Vc shown in the equation (27),
The piston stroke and capacity of the compressor are in a proportional relationship, and the stroke for easily obtaining the capacity of Vc in equation (27) is easily found using the stroke sensor, and the stroke is detected by the stroke sensor so as to reach that stroke. It is possible to obtain a desired capacity by controlling.

Further details will be described with reference to the flow charts shown in FIGS. In the vehicle air conditioner of the first embodiment of the present invention, the control device 40 reads inputs from various sensors such as an outside air temperature sensor 41, a vehicle interior temperature sensor 42, and a solar radiation sensor 43 (step 101). next,
The control device 40 controls the outside air temperature To detected by various sensors,
From the vehicle interior temperature Tr, the solar radiation amount ST, and the set temperature Tset, the target blown air temperature Tao required to bring the vehicle interior temperature to the set temperature is obtained by the equation (1) (step 102).

Further, the glass surface temperature of the window is calculated by the equation (2) from the outside air temperature To, the vehicle interior temperature Tr, and the solar radiation amount ST (step 103).

Next, the glass surface temperature Tg calculated by the equation (2)
Absolute humidity Xg with dew point is calculated by the equation (3) (step 104).

Next, the target humidity Xg-ΔXg in the passenger compartment is calculated (step 105). Next, the target humidity X in the passenger compartment
The target blowout air humidity Xao for obtaining g-ΔXg is obtained by the equation (4) (step 106). Next, the absolute humidity X
The dew point temperature Td of the air having the target outlet air humidity Xao obtained from g is obtained by the equation (6) (step 107).

Next, the dew point temperature Td is compared with the target blown air temperature Tao (step 108). As a result of comparison, T
If ao is smaller than Td, the process proceeds to step 109. In step 109, the evaporator refrigerant temperature Ter, which sets the temperature of the air after passing through the evaporator to Tea, is obtained by the equation (8), and the refrigerant temperature of the evaporator is T
The refrigerant pressure Peset of the evaporator, which is er, is obtained by the equation (9).

Next, the enthalpy i4 of the refrigerant at the inlet of the evaporator is determined by the equation (10) (step 110).
Next, the enthalpy i1 of the refrigerant at the outlet of the evaporator is calculated by the equation (11) (step 111). Next, the enthalpy is of the intake air is calculated (step 112). Here, when the air intake is performed from the outside air, the enthalpy if of the air outside the vehicle compartment is obtained by the equation (14), and this if is substituted into is. On the other hand, when the air intake is performed from the outside air, the enthalpy ir is calculated by the equation (15), and this ir is substituted for is. Further, the enthalpy ifr in the case of mixing the inside and outside air is obtained by the equation (16), and this i
Substitute fr into is.

Next, the enthalpy iea of the air after passing through the evaporator is obtained by the equation (17) (step 11).
3). Here, the air temperature Tea after passing the evaporator in this case is the target blown air temperature Tao, and the enthalpy ea of the air after passing the evaporator is the enthalpy iao of the air at the target blown air temperature Tao, so the enthalpyea is It can be obtained by the equation (17). In this case, the absolute humidity Xea of the air after passing through the evaporator is obtained by the equation (19) and is given by the equation (1
The absolute humidity Xd having the target outlet air temperature Tao in 9) as the dew point is obtained from Xd = F1 (Tao).

Next, the air volume of the air conditioner, that is, the air volume passing through the evaporator is obtained (step 114).
In this case, from FIG. 3, the target blown air temperature Tao
The air flow rate of the air conditioner is determined by obtaining the value of the applied voltage with respect to the specific value of, and obtaining the value of the air flow of the air conditioning apparatus corresponding to the value of the applied voltage from FIG. Then, from this, the cooling capacity viewed from the air side is obtained by the equation (20) (step 115). Next, the refrigerant discharge amount G is obtained by the equation (23) (step 116), and the equation (23)
The variable capacity compressor capacity Vc is calculated from the refrigerant discharge quantity G calculated by (step 117). The variable capacity compressor capacity Vc can be obtained by the equation (27).

Next, the variable capacity compressor capacity Vc
Is output to the compressor variable displacement mechanism (step 11).
8).

In this case, the air temperature Tea after passing through the evaporator is equal to the target blown air temperature Tao, that is, Tao <Td, and the compressor capacity is controlled by the equation (27) to set the air mix damper 31. All the air that is fully closed and flows through the ventilation duct 10 is passed so as to bypass the heater core 30 (step 119).
On the other hand, when Tea = Td in the comparison of step 107, that is, when Tao ≧ Td, the evaporator target refrigerant pressure Peset with the dew point temperature Td of the temperature of the air that has passed through the evaporator is obtained (step 120).
In this case, the dew point temperature Td is substituted into the temperature Tea of the air that has passed through the evaporator (Tea = Td), and the calculation of equation (9) is performed. That is, the temperature Te of the air after passing through the evaporator
The evaporator refrigerant temperature Ter at which a is the dew point temperature Td is obtained by the equation (8), and the refrigerant pressure Peset of the evaporator at which the evaporator refrigerant temperature is Ter is obtained by the equation (9).

Next, the enthalpy i4 of the refrigerant at the inlet of the evaporator is obtained by the equation (10) (step 121).
Next, the enthalpy i1 of the refrigerant at the outlet of the evaporator is calculated by the equation (11) (step 122). Next, the enthalpy is of the intake air is calculated (step 123). At this time, when the air intake is the outside air intake, the enthalpy if of the air outside the vehicle compartment is obtained by the equation (14), and the if obtained here is substituted for is. On the other hand, in the case of air in the vehicle compartment, the enthalpy ir of the air in the vehicle compartment is calculated by equation (15), and this ir is substituted for is. The enthalpy ifr in the case of mixing the inside and outside air is obtained by the equation (16), and this ifr is substituted for is.

Next, the enthalpy iea of the air after passing through the evaporator is obtained by the equation (17) (step 12).
4). In this case, the temperature Te of the air after passing through the evaporator
a is the dew point temperature Td, and the enthalpy iea of the air after passing through the evaporator is the enthalpy itd of the air at the dew point temperature Td. Therefore, the enthalpy of air after passing through the evaporator can be obtained by (17). In this case, the absolute humidity Xe of the air after passing through the evaporator
a is obtained by the equation (19), and in this case Ta
Since o ≧ Td, the absolute humidity of the air after passing through the evaporator is Xea = Xao.

Next, the air volume of the air conditioner, that is, the air volume passing through the evaporator is obtained (step 125). In this case, the value of the applied voltage for the specific value of the target blown air temperature Tao is obtained from FIG. 3, and the value of the airflow of the air conditioner corresponding to the value of the applied voltage is obtained from FIG. 4 to obtain the airflow of the air conditioner. To decide. If air intake is outside air intake, VF is calculated here.
R is calculated, and VF and R are calculated according to FIG. Then, based on these, the cooling capacity viewed from the air side is obtained by the equation (20) (step 126), and then,
The refrigerant discharge amount G is calculated by the equation (23) (step 12
7). Then, the refrigerant discharge amount G obtained by the equation (23)
Thus, the variable capacity compressor capacity Vc is obtained (step 128). The variable capacity compressor capacity Vc
Can be obtained from equation (27).

Next, the variable capacity compressor capacity Vc
To the compressor variable displacement mechanism (step 12
9), where next, if Tea = Td, ie T
When ao ≧ Td, it is necessary to set the outlet air temperature to the target outlet air temperature Tao and set the vehicle compartment temperature Tr to the vehicle compartment set temperature. Therefore, it is necessary to control the opening degree of the air mix damper 31 to raise the blown air temperature to the target blown air temperature Tao. In this case, in order to set the blown air temperature to the target blown air temperature Tao, the air mix damper 31
Heater core 30 and warm air heated by the heater core 30
The mixing ratio Υam of the cold air bypassing is obtained by the equation (28) (step 130).

The controller 40 controls the air mix damper 31 so that the mixing ratio Υam becomes a value as shown by the equation (28), so that the blown air temperature becomes the target blown air temperature Tao. Yes (Step 13
1). Then, it progresses to step 132 and step 100
The process from is repeated.

In this embodiment, the cooling capacity of the cooling machine is changed by changing the capacity of the variable capacity type compressor. However, the cooling capacity is not limited to this, and the air mixing damper like the heater shown in the embodiment is used. It is also possible to change the capacity by changing the ratio of the air passing through the evaporator, etc., or to disconnect the compressor from the engine and drive it separately by a motor etc., and control the compressor speed to change the cooling capacity. Is.

With respect to the heater, it is also possible to change the heating capacity by controlling the temperature of the hot water flowing through the heater core.

[0063]

As described above, according to the vehicle air conditioner of the present invention, the compressor is not turned on and off, the occupant's discomfort is eliminated, and the window glass can be fogged. Even underneath, it cools to the calculated value of the dew point temperature of the blown air obtained from the calculated glass surface temperature to prevent fogging of the window, but it does not cool down to the full load of the compressor as in the past. Reduce the machine load.

Further, the temperature of the window glass surface is
Since the estimation is calculated from the outside air temperature and the amount of solar radiation, it is not necessary to provide a new sensor, and the present invention can be implemented only by changing the software of the existing device.

[Brief description of drawings]

FIG. 1 is a block diagram of a vehicle air conditioner showing an embodiment according to the present invention.

FIG. 2 is a Pi diagram showing the relationship between refrigerant pressure and enthalpy.

FIG. 3 is a diagram showing a correspondence relationship between a target blown air temperature Tao and an applied voltage.

FIG. 4 is a diagram showing a correspondence relationship between an applied voltage and an air volume of an air conditioner.

FIG. 5 is a flowchart showing the control contents (first half) of the vehicle air conditioner of the present embodiment.

FIG. 6 is a flowchart showing the control contents (second half) of the vehicle air conditioner of this embodiment.

[Explanation of symbols]

 10 Ventilation duct 11 Fan 12 Electric motor 13,14 Inside / outside air switching damper 15,16 Actuator 17,18 Air outlet switching damper 21,22 Vehicle interior air intake 23,24 Outside air intake 25 Vent air outlet 26 Heater air outlet 27 Defroster air blowing Outlet 30 Heater core 31 Air mix damper 32 Evaporator 33 Condenser 34 Variable capacity compressor 35 Expansion valve 36 Fan speed controller 37 Air mix damper / actuator 40 Controller 41 Outside air temperature sensor 42 Vehicle interior temperature sensor 43 Solar radiation sensor 45 Condenser pressure sensor 46 Evaporator Pressure sensor 47 Compressor intake temperature sensor 48 Rotation sensor 49 Temperature setting device

Claims (1)

[Claims] 1. A heating unit capable of controlling a heating capacity, a cooling unit capable of controlling a cooling capacity, a preset value based on information from at least one of an outside air temperature sensor, a vehicle interior temperature sensor, and a solar radiation sensor. Target temperature calculation means for calculating a target value of the blown air temperature to control the vehicle interior temperature to the set temperature, and a glass surface temperature calculation for estimating the temperature of the window glass from the outside air temperature sensor and the vehicle interior temperature sensor Means, calculating the humidity of the blowing air required based on the humidity with the estimated glass surface temperature as the dew point, the blowing air required temperature calculating means for calculating the dew point temperature of the air of the calculated humidity, A control temperature calculation unit that compares the target temperature of the blown air with the required temperature and uses the lower temperature as the control temperature, and a cooling temperature control unit that controls the cooling capacity based on the control temperature. An air conditioner for a vehicle, comprising: a cooling control unit; and a heating control unit that controls the heating capacity based on the control temperature and the target temperature.