JP3360441B2 - Vehicle air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a vehicle.

[0002]

2. Description of the Related Art Conventionally, an air conditioner for a vehicle is provided with an inside air sensor for detecting the temperature inside the vehicle, an outside air sensor for detecting the temperature outside the vehicle, and a solar sensor for detecting the amount of solar radiation. In order to maintain the set temperature, air conditioning control is performed based on the detection values of the sensors, taking into account the temperature change inside and outside the vehicle and the influence of the amount of solar radiation.

[0003]

However, since each sensor is expensive and cost reduction is required today,
The cost occupied by each sensor is a major issue. The present invention has been made based on the above circumstances, and an object of the present invention is to provide an air conditioner for a vehicle, in which cost is reduced by eliminating an outside air sensor.

[0004]

The present invention has the following features to attain the object mentioned above. In claim 1,
A duct that guides air into the vehicle interior, cooling means arranged in the duct to cool passing air, and air introduced in the duct upstream of the cooling means and introduced into the duct A thermistor for detecting the temperature of the vehicle,
Temperature setting means for setting a set temperature in the vehicle,
Inside air temperature detecting means for detecting an air conditioning temperature;
In the outside air mode in which outside air is introduced into the
The detected value of the data is processed as the outside air temperature, and the outside air temperature and
A set temperature set by the temperature setting means;
Air conditioning control means for performing air conditioning control based on the vehicle interior temperature detected by the air temperature detection means .

[0005]

According to a second aspect of the present invention , there is provided a duct for guiding air into the vehicle interior, a refrigerant compressor for compressing and discharging the sucked refrigerant, and a low-temperature and low-pressure low-pressure compressor disposed in the duct and supplied by the operation of the refrigerant compressor. A refrigeration cycle having a refrigerant evaporator that cools the air passing therethrough by heat exchange with the refrigerant, and disposed downstream of the refrigerant evaporator in the duct to detect the temperature of the air that has passed through the refrigerant evaporator. A thermistor, compressor control means for controlling on / off of the refrigerant compressor based on a detection value of the thermistor, air conditioning control means for performing air conditioning control in response to a change in vehicle environmental conditions including outside air temperature, In an outside air mode in which outside air is introduced into the duct, an outside air temperature is estimated based on a degree of change in a detection value of the thermistor after the refrigerant compressor is switched from on to off. And a temperature estimation means, said air conditioning control means replaces the estimated outside air temperature estimated by said ambient temperature estimating means to said outside air temperature and performing air-conditioning control.

According to a third aspect of the present invention , there is provided a duct for guiding air into the vehicle interior, a refrigerant compressor for compressing and discharging the sucked refrigerant, and a low-temperature, low-pressure low-pressure compressor disposed in the duct and supplied by the operation of the refrigerant compressor. A refrigeration cycle having a refrigerant evaporator that cools the air passing therethrough by heat exchange with the refrigerant, and disposed downstream of the refrigerant evaporator in the duct to detect the temperature of the air that has passed through the refrigerant evaporator. A thermistor, compressor control means for controlling on / off of the refrigerant compressor based on a detection value of the thermistor, air conditioning control means for performing air conditioning control in response to a change in vehicle environmental conditions including outside air temperature, to the outside air mode for introducing outside air into the duct, and a fresh air Yutaka推 constant means for estimating the outside air temperature based on the off-time of the on / off cycle of the refrigerant compressor,
The air conditioning control unit performs air conditioning control by replacing the estimated outside air temperature estimated by the outside air temperature estimation unit with the outside air temperature.

[0008]

According to the first aspect of the present invention, since the thermistor is provided on the windward side of the cooling means disposed in the duct, in the outside air mode in which outside air (outside air) is introduced into the duct, the thermistor is turned off. The air conditioning control can be performed by replacing the detected value with the outside air temperature. Specifically, the air conditioning control is performed based on the set temperature setting temperature setting means, detected by the inside air temperature detection means vehicle interior temperature, and the detection value of the thermistor (outside air temperature). As the cooling means, for example, a refrigerant condenser of a refrigeration cycle can be used.

[0009] The present invention as set forth in claim 2 is provided with a thermistor on the lee of the refrigerant evaporator disposed in a duct. Therefore, when the refrigerant compressor is switched from on to off in the outside air mode, the detection value of the thermistor increases with the introduction of outside air into the duct. The temperature rise of this thermistor
The degree of change differs according to the outside air temperature. That is, the higher the outside air temperature, the greater the temperature rise of the thermistor,
The lower the outside air temperature, the smaller the degree of temperature rise of the thermistor. Thus, the outside air temperature estimating means can estimate the outside air temperature based on the degree of change of the thermistor (the degree of temperature rise). Then, the air conditioning control means performs air conditioning control by replacing the estimated outside air temperature estimated by the outside air temperature estimation means with the outside air temperature (as the outside air temperature).

According to a third aspect of the present invention, the on / off control of the refrigerant compressor is performed based on a detection value of a thermistor disposed downstream of the refrigerant evaporator. Here, in the outside air mode, the higher the outside air temperature, the greater the degree of temperature rise of the thermistor after the refrigerant compressor is switched from on to off, so that the off time of the refrigerant compressor is shorter than when the outside air temperature is low. Be shorter. Conversely, the lower the outside air temperature, the longer the off time of the refrigerant compressor than when the outside air temperature is high. Thus, the outside air temperature estimating means can estimate the outside air temperature based on the off time of the on / off cycle of the refrigerant compressor.
Then, the air conditioning control unit replaces the estimated outside air temperature estimated by the outside air temperature estimation unit with the outside air temperature (as the outside air temperature).
Perform air conditioning control.

The air-conditioning control performed by the air-conditioning control means according to the second and third aspects includes, for example, a blower that introduces air into a duct and sends the air into a vehicle compartment, and a hot air and a cold air flowing through the duct. To control the operation of an air mix damper for adjusting the mixing ratio, an outlet switching damper for switching the outlet, or a valve provided in a hot water pipe connected to the hot water heater core.

[0012]

Next, a first embodiment of the air conditioner for a vehicle according to the present invention will be described with reference to FIGS. FIG. 1 is an overall schematic diagram of an air conditioner for a vehicle. The vehicle air conditioner 1 (hereinafter, referred to as an air conditioner 1) of the present embodiment includes a duct 2 that guides air into a vehicle interior, a blower 3 that introduces air into the duct 2 and sends the air into the vehicle interior, and cooling means. The air conditioner includes a refrigeration cycle 4, a hot water circuit 5 constituting a heating means, and an air conditioner control device 6 (air conditioning control means of the present invention, see FIG. 2).

The duct 2 has a branch duct 2 at its downstream end.
a, 2b, and 2c are connected to each of the branch ducts 2a to 2c.
Are connected to outlets 7, 8, and 9 that open into the vehicle interior. The outlets 7 to 9 are a defroster outlet 7 for blowing air toward the window glass 10 of the vehicle, a face outlet 8 for blowing air toward the upper body of the occupant, and a foot outlet 9 for blowing air toward the feet of the occupant. Consists of The outlets 7 to 9 are selectively opened and closed by outlet switching dampers 11 and 12 provided at the upstream openings of the branch ducts 2a to 2c.

The blower 3 comprises a blower case 3a, a centrifugal fan 3b, and a blower motor 3c, and the number of revolutions of the blower motor 3c is determined according to the voltage (blower voltage) applied to the blower motor 3c. In the blower case 3a,
An inside air inlet 13 for introducing vehicle interior air (inside air) and an outside air inlet 14 for introducing air outside the vehicle (outside air) are formed, and inside and outside for selectively opening and closing the inside air inlet 13 and the outside air inlet 14. An air switching damper 15 is provided.

The refrigeration cycle 4 receives a blower of a cooling fan 19 which receives a high-temperature and high-pressure refrigerant compressed by the refrigerant compressor 18 driven by a vehicle engine 17 via an electromagnetic clutch 16. Condenser 20 for condensing and liquefying the refrigerant, a receiver 21 for temporarily storing the refrigerant condensed in the refrigerant condenser 20 and flowing only the liquid refrigerant, a decompression device 22 for decompressing and expanding the liquid refrigerant guided from the receiver 21, and a duct 2 , A refrigerant evaporator 23 (cooling means of the present invention) that evaporates the low-temperature and low-pressure refrigerant depressurized by the decompression device 22 by receiving the air blown by the blower 3 and comprises a refrigerant pipe 24. Are connected in a ring.

The operation of the refrigerant compressor 18, ie, the electromagnetic clutch 16 is turned on by the air conditioner control device 6.
The clutch drive circuit 25 (FIG. 2)
ON / OFF control. Specifically, as shown in FIG. 3, the air temperature before passing through the refrigerant evaporator 23 (hereinafter referred to as the pre-evacuation temperature) and the air temperature after passing through the refrigerant evaporator 23 and cooled (hereinafter referred to as the evaporator temperature). ON / OFF control is performed based on the relationship with the temperature.

The hot water circuit 5 includes a refrigerant evaporator 2 inside the duct 2.
The heater core 26 is disposed downstream of the heater 3 and heats the air flowing through the duct 2 using the cooling water of the engine 17 as a heat source.
And a hot water pipe 27 for annularly connecting the heater core 26 to a cooling water circuit (not shown) of the engine 17. The heater core 26 is connected to the refrigerant evaporator 23 in the duct 2.
The air passing through the heater core 26 is arranged to form a bypass 28 that flows around the heater core 26. The ratio between the amount of air passing through the heater core 26 and the amount of air passing through the bypass passage 28 is adjusted by an air mix damper 29 arranged on the windward side of the heater core 26.

The air conditioner control device 6 has a built-in microcomputer (not shown) in which a control program, an arithmetic expression and the like relating to the air conditioning control are stored. As shown in FIG. 2, the air conditioner control device 6 includes an operation signal output from the air conditioner operation panel 30, sensors 31 to 33 (described later), pre-evaporation thermistor 34, and output from the post-evaporation thermistor 35. Based on the signal, the clutch drive circuit 25 and each damper (the air outlet switching damper 11, 1
2, inside / outside air switching damper 15, air mix damper 29)
The control signals are output to servo motors 36, 37, 38 for driving the motor, a motor drive circuit 39 for driving the blower motor 3c, and the like.

The air conditioner operation panel 30 is provided with a temperature setting volume 40 (temperature setting means of the present invention) for setting a desired room temperature by an occupant and outputting a set temperature signal Tset corresponding to the room temperature. I have.

Each of the above-mentioned sensors detects an inside air temperature and outputs an inside air temperature signal Tr as an inside air temperature sensor 31 (inside air temperature detecting means of the present invention).
a solar radiation sensor 32 which outputs the temperature as s; a water temperature sensor 33 which detects the temperature of the engine cooling water and outputs the temperature as a water temperature signal Tw.

The pre-evaporation thermistor 34 is disposed in the duct 2 on the windward side of the refrigerant evaporator 23 (immediately before the refrigerant evaporator 23), and outputs the detected pre-evaporation temperature to the air conditioner control device 6 as a pre-evaporation temperature signal Tei. Output. After Eva Thermistor 35
Is disposed downstream of the refrigerant evaporator 23 (immediately after the refrigerant evaporator 23), and outputs the detected post-evaporation temperature to the air conditioner control device 6 as the post-evaporation temperature signal Teo.

Next, the operation of the present invention will be described with reference to the air conditioner control device 6.
A description will be given based on the processing procedure. FIG. 4 is a flowchart showing a processing procedure of the air conditioner control device 6. First, initialization of various counters and flags is performed (Step S).
1). Next, the set temperature signal Tset output from the temperature setting knob 40 and the detection signals (T
r, Ts, Tw), the detection signal T of the pre-evacuation thermistor 34
ei and the detection signal Teo of the post-evaporation thermistor 35 are read (step S2).

Subsequently, the outside air temperature is specified (step S).
3). The specification of the outside air temperature is performed as follows.
When the engine is started or the air conditioner 1 is started, the detection signal Tei of the pre-evacuation thermistor 34 is input as the outside air temperature signal Tam. Thereafter, if the suction port mode determined in the following step S7 is the outside air mode, since outside air is introduced into the duct 2, the detection signal Tei of the pre-evacuation thermistor 34 is similarly input as the outside air temperature signal Tam. . That is,
When the engine is started, when the air conditioner 1 is started, and in the outside air mode, the pre-evacuation temperature detected by the pre-evacuation thermistor 34 is processed as the outside air temperature.

If the suction port mode determined in step S7 is the inside air mode, the outside air temperature cannot be detected by the pre-evacuation thermistor 34.
For example, the average temperature of Japan throughout the four seasons (here, 15
° C) is the outside air temperature. The predetermined temperature (15 ° C.) is stored in the microcomputer of the air conditioner control device 6 in advance, and when the inside air mode is selected, the predetermined temperature (1 ° C.)
(5 ° C.) is calculated as the outside air temperature signal Tam.

Subsequently, the information read in step S2,
And from the outside temperature signal Tam specified in step S3,
A target outlet temperature TAO into the vehicle compartment is calculated based on the following equation (step S4).

[Equation 1] TAO = Kset · Tset−Kr · Tr−Kam ·
Tam−Ks · Ts + C Kset: temperature setting gain, Kr: inside air temperature gain, Kam: outside air temperature gain, Ks: solar radiation gain, C:
It is a correction constant.

Subsequently, the target opening degree SW of the air mix damper 29 is calculated according to the following equation so that the actual blown temperature into the vehicle compartment becomes the target blowout temperature TAO calculated in step S4 (step S5). ).

SW = [(TAO-Teo) / (Tw-Teo)]
× 100 (%)

Subsequently, based on the target outlet temperature TAO calculated in step S4, the blower voltage, the suction port mode,
The outlet mode is determined from each of the characteristic diagrams shown in FIGS. 5 to 7 (steps S6 to S8). FIG.
7 are stored in the microcomputer in advance.

Subsequently, a control signal is output to each of the servomotors 36 to 38 and the motor drive circuit 39 so that each target value can be obtained, and the air outlet switching dampers 11 and 12, the inside / outside air switching damper 15, the air mix The damper 29 and the blower motor 3c are controlled (step S9). Subsequently, it is determined whether a predetermined control cycle τ has elapsed (step S1).
0), when it has elapsed (YES), the processing of step S2 and subsequent steps is repeated. If the decision result in the step S10 is NO, the step S10 is performed until a predetermined control cycle τ elapses.
repeat.

As described above, in the outside air mode, the detected temperature (pre-evacuation temperature) of the pre-evacuation thermistor 34 relating to the ON / OFF control of the electromagnetic clutch 16 is input as the outside air temperature, and in the inside air mode, a preset temperature is set. By setting the predetermined temperature (15 ° C.) as the outside air temperature, the same control as the outside air temperature correction (see FIG. 8) conventionally performed using the outside air sensor can be performed without using the outside air sensor.

In the first embodiment, a certain temperature (15 ° C.) is set as the outside air temperature in the inside air mode. However, the temperature is detected by the pre-evaporation thermistor 34 when the engine is started, the air conditioner is started, or the outside air mode. The detected temperature may be stored, and the detected temperature may be used as the outside air temperature in the inside air mode.

Next, a second embodiment of the present invention will be described. In this embodiment, the pre-evacuation thermistor 3 described in the first embodiment is used.
A vehicle air conditioner 1 not provided with the air conditioner 4 (hereinafter referred to as an air conditioner 1) will be described. However, the configuration of the air conditioner 1 (see FIG. 1) is the same as that of the first embodiment except that the pre-evaporation thermistor 34 is not provided, and a description thereof will be omitted.

The operation of this embodiment will be described below. FIG.
5 is a flowchart showing the operation of the present embodiment. First,
Initialize various counters and flags (step S
20). Next, the set temperature signal Tset output from the temperature setting volume 40, the detection signals (Tr, Ts, Tw) of the sensors 31 to 33, and the detection signal Teo of the post-evaporation thermistor 35 are read (step S21).

Subsequently, the outside air temperature is estimated (step S).
22). The estimation of the outside air temperature is performed based on the following procedure (a flowchart is shown in FIG. 10). First,
The suction port mode is determined (step 22a). Here, when it is determined that the outside air mode is set, the change rate θ of the post-evaporation thermistor 35 after the refrigerant compressor 18 is switched from ON to OFF is calculated, and the outside air temperature is estimated based on the change rate θ (step 22b) The outside air temperature estimating means according to claim 2 .

The processing in step 22b will be described. Refrigerant compressor 18 is off from ON when in outside air mode
Then, the detection value of the post-evaporation thermistor 35 increases with the introduction of outside air into the duct 2. The degree of change (rate of change) of the temperature rise of the post-evaporation thermistor 35 varies depending on the outside air temperature. That is, as shown in FIG.
If the outside air temperature is high, t after the refrigerant compressor 18 is turned off
When the temperature rise rate (change rate θ ₂ ) per _second is large and the outside air temperature is low, the temperature rise rate (change rate θ ₁ ) in t seconds after the refrigerant compressor 18 is turned off decreases.

Therefore, in the outside air mode, the outside air temperature can be estimated based on the rate of change θ of the post-evaporation thermistor 35 after the refrigerant compressor 18 switches from ON to OFF. The refrigerant compressor 18 (electromagnetic clutch 16)
As shown in FIG. 12, the air conditioner is ON / OFF controlled by the air conditioner control device 6 (compressor control means of the present invention) based on the detection value of the post-evaporation thermistor 35.

On the other hand, if the inside air mode is determined in step 22a, the outside air temperature cannot be estimated as in the outside air mode. Therefore, a certain predetermined temperature (see the first embodiment) is estimated as the outside air temperature. (Step 22c). Then, the temperature estimated in step 22b or step 22c is set as the outside air temperature (step 22d).

After the outside air temperature is obtained in step S22,
The processes in steps S23 to S29 are performed in the same manner as the processes in steps S4 to S10 (see FIG. 4) of the first embodiment (the description is omitted). in this way,
In this embodiment, even without the pre-evacuation thermistor 34, the air-conditioning control can be performed by estimating the outside air temperature based on the rate of change θ of the post-evaporation thermistor 35 in the outside air mode.

Next, a third embodiment of the present invention will be described. This embodiment is different from the second embodiment in the method of estimating the outside air temperature. Hereinafter, the process of step S22 for estimating the outside air temperature will be described. FIG. 13 shows a flowchart for estimating the outside air temperature. If it is determined in step 22a that the air mode is the outside air mode, the refrigerant compressor 18 is turned on / off.
Estimating the outside air temperature based on OFF time F cycle (outside air Yutaka推 constant means step 22b '· Claim 3). The OFF time of the refrigerant compressor 18 differs depending on the outside air temperature introduced into the duct 2 in the outside air mode.

That is, in the outside air mode, the higher the outside air temperature, the greater the temperature rise of the post-evaporation thermistor 35 after the refrigerant compressor 18 is switched from ON to OFF, as shown in FIG. OFF time t ₁ of the refrigerant compressor 18 than when the outside air temperature is low, the shorter. Conversely,
When the outside air temperature is low, OFF time t ₂ of the refrigerant compressor 18 than when the outside air temperature is high is longer. Accordingly, in the outside air mode, the ON / OFF cycle of the refrigerant compressor 18 is turned off.
The outside air temperature can be estimated based on the time.

On the other hand, if the inside air mode is determined in step 22a, a certain predetermined temperature is estimated as the outside air temperature as in the second embodiment (step 22c). in this way,
Also in the present embodiment, similarly to the second embodiment, the outside air temperature can be estimated in the outside air mode even without the pre-evaporation thermistor 34.

In the second embodiment and the third embodiment,
Although a certain predetermined temperature (15 ° C.) is set as the outside air temperature in the inside air mode, the temperature estimated in the outside air mode may be stored, and the estimated temperature may be used as the outside air temperature in the inside air mode.

[0042]

According to the first aspect of the present invention, the thermistor disposed on the windward side of the cooling means in the duct,
The outside air temperature in the outside air mode can be detected. Further, in the internal regulation mode, air conditioning control (outside air temperature correction) is performed without using an outside air sensor by setting a predetermined temperature set in advance or a temperature detected by a thermistor in the outside air mode as an outside air temperature. be able to. As a result, the cost can be reduced by eliminating the outside air sensor.

[0043] Further, as described in claims 2 and 3, in the air conditioner for a vehicle to turn on / off control of the refrigerant compressor based on the detected value of the thermistor disposed downwind of the refrigerant evaporator Even without a thermistor on the windward side of the refrigerant evaporator, it is possible to estimate the outside air temperature in the outside air mode and perform air conditioning control (outside air temperature correction). Thus, similarly to the first aspect of the present invention, the cost can be reduced by eliminating the outside air sensor.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of a vehicle air conditioner according to an embodiment.

FIG. 2 is a block diagram related to a control system of the first embodiment.

FIG. 3 is a graph showing control characteristics of a refrigerant compressor (electromagnetic clutch) (first embodiment).

FIG. 4 is a flowchart showing the operation of the first embodiment.

FIG. 5 is a control characteristic diagram of the blower.

FIG. 6 is a control characteristic diagram of the suction port mode.

FIG. 7 is a control characteristic diagram in an outlet mode.

FIG. 8 is a graph showing a control example of outside air temperature correction.

FIG. 9 is a flowchart showing the operation of the second embodiment.

FIG. 10 is a flowchart showing a procedure for estimating an outside air temperature (second embodiment).

FIG. 11 is a graph showing a rate of change of a post-evaporation thermistor after a refrigerant compressor is turned off (second embodiment).

FIG. 12 is a graph showing control characteristics of a refrigerant compressor (electromagnetic clutch) (second embodiment).

FIG. 13 is a flowchart illustrating a procedure for estimating an outside air temperature (third embodiment);

FIG. 14 is a graph showing an on / off cycle of the refrigerant compressor (third embodiment).

[Explanation of symbols]

REFERENCE SIGNS LIST 1 air conditioner (vehicle air conditioner) 2 duct 4 refrigeration cycle 6 air conditioner control device (air conditioning control means, compressor control means) 18 refrigerant compressor 23 refrigerant evaporator (cooling means) 31 inside air sensor (inside air temperature detecting means) 34 Thermistor before evaporation (thermistor according to claim 1 ) 35 Thermistor after evaporation (thermistor according to claims 2 and 3 ) 40 Temperature setting volume (temperature setting means)

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hajime Ono 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-57-158118 (JP, A) JP-A-59- 137209 (JP, A) JP-A-62-178415 (JP, A) JP-A-3-176225 (JP, A) JP-A 55-33808 (JP, U) JP-A 62-203713 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) B60H 1/32 623 B60H 1/32 613 B60H 1/00

Claims (3)

(57) [Claims] A) a duct for guiding air into a vehicle compartment; b) a cooling means disposed in the duct to cool passing air; c) a windward in the duct above the cooling means. Being
A) a thermistor for detecting the temperature of the air introduced into the duct; d) temperature setting means for setting a set temperature in the cabin; e) inside air temperature detecting means for detecting an air conditioning temperature in the cabin.
And f) in an outside air mode in which outside air is introduced into the duct.
Processing the detected value of the thermistor as outside air temperature,
The outside air temperature and the set temperature set by the temperature setting means.
And the temperature in the vehicle cabin detected by the inside air temperature detecting means.
An air conditioner for a vehicle, comprising: an air conditioning control unit that performs air conditioning control based on a degree . 2. a) a duct for guiding air into a vehicle compartment; b) a refrigerant compressor for compressing and discharging the sucked refrigerant; and a low-temperature compressor disposed in the duct and supplied by the operation of the refrigerant compressor. A refrigeration cycle having a refrigerant evaporator that cools air passing therethrough by heat exchange with a low-pressure refrigerant; c) disposed downstream of the refrigerant evaporator in the duct;
A) a thermistor for detecting the temperature of the air passing through the refrigerant evaporator; d) compressor control means for controlling on / off of the refrigerant compressor based on a detection value of the thermistor; and e) a vehicle including an outside air temperature. Air-conditioning control means for performing air-conditioning control in response to changes in environmental conditions; f) detection of the thermistor after the refrigerant compressor is switched from on to off in an outside air mode in which outside air is introduced into the duct. Outside air temperature estimating means for estimating the outside air temperature based on the degree of change of the value, wherein the air conditioning control means performs air conditioning control by replacing the estimated outside air temperature estimated by the outside air temperature estimating means with the outside air temperature. An air conditioner for a vehicle, comprising: 3. a) a duct for guiding air into a vehicle compartment; b) a refrigerant compressor for compressing and discharging the sucked refrigerant; and a low-temperature compressor disposed in the duct and supplied by the operation of the refrigerant compressor. A refrigeration cycle having a refrigerant evaporator that cools air passing therethrough by heat exchange with a low-pressure refrigerant; c) disposed downstream of the refrigerant evaporator in the duct;
A) a thermistor for detecting the temperature of the air passing through the refrigerant evaporator; d) compressor control means for controlling on / off of the refrigerant compressor based on a detection value of the thermistor; and e) a vehicle including an outside air temperature. Air-conditioning control means for performing air-conditioning control in response to changes in environmental conditions; and f) an outside air temperature based on an off time of an on / off cycle of the refrigerant compressor in an outside air mode in which outside air is introduced into the duct. and a fresh air Yutaka推 constant means for estimating the air conditioning control unit, the vehicle air conditioning, characterized in that to perform air-conditioning control is replaced by the estimated outside air temperature estimated by the outside air temperature estimating means to said outside air temperature apparatus.