JP3344161B2 - 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 in which air from a plurality of temperature fields, such as inside air and outside air, is introduced to exchange heat with a refrigerant in an evaporator.

[0002]

2. Description of the Related Art A conventional air conditioner for a vehicle of this type has been proposed in Japanese Patent Application Laid-Open No. 5-124426. In this air conditioner, a ventilation passage having an evaporator and a heater core is provided in a ventilation direction. The first air passage leading to the defroster outlet and the second air passage leading to the foot outlet are divided into two. Then, when the outside temperature is low in winter, low-humidity outside air is introduced into the first ventilation path to exchange heat with the evaporator and the heater core. It can be removed well.

[0003] On the other hand, high temperature inside air is introduced into the second ventilation path to exchange heat with the evaporator and the heater core.
By blowing warm air from the foot outlet into the cabin,
The vehicle interior can be heated rapidly. In other words, it is intended to ensure both the performance of removing the fogging of the window glass and the rapid heating of the vehicle interior at the time of low outside temperature in winter.

[0004]

As described above, when the air introduced into the evaporator at a low outside air temperature is composed of air (inside air and outside air) from two temperature fields, the most downstream portion of the evaporator needs to be installed. If the flowing refrigerant is configured to exchange heat with the low-temperature outside air, the refrigerant at the most downstream portion of the evaporator may not lose heat from the air but instead may lose heat from the air.

In a vehicle air conditioner, a temperature-type expansion valve is usually used as a pressure reducing means. Therefore, when the refrigerant at the most downstream portion of the evaporator loses heat to the air as described above, it is provided at the evaporator outlet. The temperature of the refrigerant sensed by the temperature sensing cylinder also decreases, the opening degree of the expansion valve decreases, and the refrigerant flow rate is reduced. As a result, the expansion valve cannot control the refrigerant flow rate in accordance with the heat load of the evaporator,
The flow rate of the refrigerant is narrowed more than necessary, and the dehumidifying ability of the evaporator is reduced.

[0006] The present invention has been made in view of the above points,
It is an object of the present invention to improve the dehumidifying ability of an evaporator in a vehicle air conditioner that performs heat exchange with an evaporator by introducing air from a plurality of temperature fields.

[0007]

In order to achieve the above object, the present invention employs the following technical means. According to the first aspect of the present invention, air from a plurality of temperature fields is introduced, the introduced air exchanges heat with the refrigerant in the evaporator (18), and is provided at a refrigerant inlet to the evaporator (18). The air conditioner for a vehicle provided with a temperature-type expansion valve (40) that adjusts the flow rate of the refrigerant according to the degree of superheat of the refrigerant at the outlet of the evaporator (18).
The air-conditioning system for a vehicle is characterized in that the refrigerant most downstream portion (18b) is disposed at a portion where air having a temperature higher than the lowest temperature among the air from the plurality of temperature fields is introduced.

According to the second aspect of the present invention, air from a plurality of temperature fields is introduced, the introduced air exchanges heat with the refrigerant in the evaporator (18), and the refrigerant inlet to the evaporator (18). The air conditioner for a vehicle, further comprising a temperature-type expansion valve (40) that adjusts a refrigerant flow rate according to a degree of superheat of the refrigerant at an outlet of the evaporator (18) as a pressure reducing means provided in the evaporator (18). ) The most downstream part of the refrigerant (18b)
Refrigerant in the air from the plurality of temperature fields,
The vehicle air conditioner is characterized in that the evaporator (18) is arranged in the flow path (22, 23) of the introduced air so as to exchange heat with air having a temperature higher than the minimum temperature.

According to a third aspect of the present invention, in the vehicle air conditioner according to the first or second aspect, the evaporator (1
8) The refrigerant upstream-most part and the refrigerant downstream-most part (18b) are connected by one refrigerant flow path (18c). According to a fourth aspect of the present invention, in the vehicle air conditioner according to the first or second aspect, a plurality of refrigerant evacuation units (18) are provided in parallel between a refrigerant most upstream part and a refrigerant most downstream part (18b). It is characterized by being connected by the provided refrigerant flow path (18d).

According to the fifth aspect of the present invention, air from a plurality of temperature fields is introduced, the introduced air is exchanged with refrigerant in an evaporator (18), and a refrigerant inlet to the evaporator (18) is provided. The air conditioner for a vehicle, further comprising a temperature-type expansion valve (40) that adjusts a refrigerant flow rate according to a degree of superheat of the refrigerant at an outlet of the evaporator (18) as a pressure reducing means provided in the evaporator (18). ) Is connected by a plurality of refrigerant passages (18d) provided in parallel between the most upstream part of the refrigerant and the most downstream part (18b) of the refrigerant, and the most downstream part (18b) of the evaporator (18) is connected. ), The evaporator (18) causes the flow of the introduced air to exchange heat with the air having the lowest temperature and the air having a temperature higher than the lowest temperature among the air from the plurality of temperature fields. Roads (22, 23), Refrigerant downstream portion of the vessel (18) (18
From the cross-sectional area (Sb) of the air flow path in which the refrigerant and the lowest temperature air exchange heat in b), the temperature of the refrigerant and the lowest temperature in the refrigerant most downstream part (18b) of the evaporator (18) is higher than the lowest temperature. The cross-sectional area of the air flow path where heat exchanges with air (S
It is characterized by a vehicle air conditioner in which a) is set to be large.

The reference numerals in the parentheses of the above means indicate the correspondence with the concrete means described in the embodiments described later.

[0012]

According to the first to fifth aspects of the present invention,
Because of the above technical means, in a vehicle air conditioner that introduces air from a plurality of temperature fields and exchanges heat with the evaporator, the refrigerant at the lowest downstream portion of the evaporator has the lowest temperature air. Since the refrigerant exchanges heat with air at a higher temperature and the refrigerant absorbs heat more reliably than air, the refrigerant flowing out to the outlet pipe of the evaporator always has a proper degree of superheat corresponding to the heat load of the evaporator. Become. Therefore, the temperature-type expansion valve can sense the refrigerant temperature indicating the appropriate degree of superheat, the valve opening of the temperature-type expansion valve becomes an appropriate degree of opening corresponding to the heat load of the evaporator, and the appropriate refrigerant flow rate can be set. Therefore, the dehumidifying ability of the evaporator can be ensured well.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. (First Embodiment) FIG. 1 shows the entire configuration of the first embodiment. An air conditioner 1 is mounted on an automobile, and a duct 2 forming an air passage for blowing air toward a vehicle interior is provided. Have. At one end of the duct 2, two electric blowers 3 and 4 for blowing air into the duct 2 are arranged.

The first blower 3 is provided with inside / outside air switching means 5 for switching the air introduced into the duct 2 between inside air (vehicle interior air) and outside air (vehicle outside air). An inside air introduction port 6 for introducing inside air, an outside air introduction port 7 for introducing outside air, and an inside / outside air switching door 8 are provided.
The passage switching operation of the door 8 switches the air introduced into the first blower 3 between inside air and outside air.

On the other hand, the second blower 4 always sucks inside air, and has only the inside air inlet 9 for introducing inside air. At the other end of the duct 2, an air outlet for blowing air that has passed through the duct 2 into the vehicle interior is provided. The air outlet is located at the center of the front part (instrument panel) of the vehicle interior and the upper body of the occupant. From the center face outlet 10 that mainly blows out cold air toward the front, and from both left and right sides of the front part (instrument panel part) in the vehicle interior,
A side face outlet 11 for blowing cold air or hot air toward the occupant's upper body or side window glass, a defroster outlet 12 for blowing hot air mainly toward the windshield, and mainly toward the feet of the occupant. And a foot outlet 13 for blowing out warm air.

At the other end of the duct 2, a center face door 14, which controls the flow of air to each of the air outlets, through air passages leading to the other air outlets 10, 12, and 13 except the side face air outlet 11. A defroster door 16 and a foot door 17 are provided. An evaporator 18 as a cooling means for cooling and dehumidifying air is installed in a portion of the duct 2 immediately downstream of the blowers 3 and 4. A heater core 19 as a heating means for heating air is provided downstream of the evaporator 18. Also, in duct 2,
A cooling bypass passage 20 for bypassing the evaporator 18 and a heating bypass passage 21 for bypassing the heater core 19
Is provided. By having both of the bypass passages 20 and 21, a first flow passage 22 passing only through the evaporator 18, a second flow passage 23 passing through both the evaporator 18 and the heater core 19, and a heater core A third flow path 24 passing only through 19 can be formed.

The heating bypass passage 21 located downstream of the evaporator 18 is provided with a cool door 25 for opening and closing the passage 21. By closing the heating bypass passage 21 with the cool door 25, the evaporator 18 is closed. All air passing through the heater core 19 passes through the heater core 19. Also, upstream of the evaporator 18 in the duct 2,
The first partition wall 2 that is introduced into the evaporator 18 while the air blown by the first blower 3 and the air blown by the second blower 4 are separated.
6 is provided, and a second partition wall 27 is provided downstream of the evaporator 18 to separate air that has passed through the evaporator 18 and air that has passed only through the heater core 19 without passing through the evaporator 18. Have been. The heater core 19 is installed in the duct 2 so as to penetrate the second partition wall 27.

Downstream of the second partition wall 27 is a differential mode opening 2 for guiding air that has passed only through the heater core 19 to the defroster outlet 12 in the defroster mode.
The differential mode opening 28 is provided with a differential mode door 29 that opens and closes the differential mode opening 28. The differential mode door 29 is operated so as to open the differential mode opening 28 when the defroster mode is selected by a blowing mode switching member of an air conditioning operation panel (not shown).

Next, the configuration of the refrigeration cycle 32 having the evaporator 18 will be described. The refrigeration cycle 32 includes, in addition to the evaporator 18, a compressor 34 and a condenser 3 as well known.
7, a receiver 39, and a thermal expansion valve 40. The compressor 34 is provided with an electromagnetic clutch 35. When the electromagnetic clutch 35 is energized, the electromagnetic clutch 35 is connected, and the rotational force of the vehicle engine 33 is reduced by the belt 36.
The signal is transmitted to the compressor 34 via the electromagnetic clutch 35, and the compressor 34 is started. The above-described heater core 19 is configured by a hot water heat exchanger that heats the blown air using cooling water (hot water) of the vehicle engine 33 as a heat source.

Of the components of the refrigeration cycle 32,
Other devices except for the evaporator 18 and the thermal expansion valve 40 (34,
37, 39) are installed in the engine room 31 of the automobile. The condenser 37 is provided with a cooling fan 38 for blowing the cooling air, and the air blown by the cooling fan 38 exchanges heat with the refrigerant to cool and condense the refrigerant. The receiver 38 forms a gas-liquid separation unit that stores the liquid refrigerant condensed in the condenser 37, separates the gas refrigerant and the liquid refrigerant, and derives only the liquid refrigerant.

The temperature type expansion valve 40 is installed near the evaporator 18 in the passenger compartment. In order to maximize the cooling capacity of the evaporator 18, the temperature expansion valve 40 is set so that the refrigerant is completely evaporated at the evaporator outlet. The valve opening (refrigerant flow rate) is automatically adjusted. For this purpose, the temperature-type expansion valve 40 has a temperature-sensitive cylinder 40a installed in the outlet pipe 41 of the evaporator 18, and the outlet refrigerant temperature of the evaporator 18 detected by the temperature-sensitive cylinder 40a,
The degree of superheat of the refrigerant at the outlet of the evaporator 18 is determined based on the refrigerant evaporation pressure of the evaporator 18, and the valve opening of the temperature-type expansion valve 40 is automatically adjusted so that the degree of superheat of the refrigerant at the outlet is maintained at a predetermined value. It is being adjusted.

The arrangement of the evaporator 18 in the duct 2 in this embodiment is, as shown in FIG. 1, a refrigerant most upstream portion 18a into which the gas-liquid two-phase refrigerant decompressed by the thermal expansion valve 40 flows. Are located in the blast air flow path of the first blower 3, and the refrigerant most downstream portion 18 b is located in the blast air flow path of the second blower 4. Here, since the second blower 4 always blows inside air, the most downstream part 18b of the refrigerant of the evaporator 18 is
When air in a plurality of temperature fields of the inside and outside air is introduced, the air is arranged at a site where the air with the higher temperature is introduced.

In this embodiment, one refrigerant flow path 18c is connected between the most upstream refrigerant portion 18a and the most downstream refrigerant portion 18b of the evaporator 18. In this example, as shown in FIG. 1, the outlet pipe 41 connected to the refrigerant most downstream portion 18 b of the evaporator 18 is located in the duct 2. , Heat exchange with low temperature outside air is possible. Therefore, it is preferable to attach a heat insulating material to the outer peripheral surface of the outlet pipe 41 to prevent heat exchange with low-temperature outside air.

Further, an outlet pipe 41 connected to the refrigerant most downstream part 18b of the evaporator 18 is piped immediately outside the duct 2 from the part of the refrigerant most downstream part 18b of the evaporator 18 so that the outlet pipe 41 May be configured not to exchange heat with the air blown by the first blower 3. Next, the operation of the present embodiment in the above configuration will be described. At the time of low outside temperature in winter, when the interior of the vehicle is heated and the windshield is prevented from fogging simultaneously, the inside / outside air switching door 8 is operated to the position indicated by the solid line in FIG. The inlet 7 is opened. Further, the cool door 25 is operated to the position indicated by the dashed line in FIG. 1 to open the heating bypass passage 21.

The differential mode door 29 is operated to the position indicated by the solid line in FIG. 1 to close the differential mode opening 28. The center face door 14 is closed, and the defroster door 16 is closed.
Is opened and the foot door 17 is operated to the open position, and the defroster outlet 12 and the foot outlet 1 are operated.
3 allows air to be blown out. When a refrigeration cycle operation switch (air conditioning switch) not shown is turned on,
Electric power is supplied to the electromagnetic clutch 35, and the compressor 34 starts.

When the first blower 3 is operated, low-temperature outside air outside the vehicle is sucked into the duct 2 through the outside air inlet 7. At the same time, when the second blower 4 is operated, the inside air having a higher temperature than the outside air is sucked into the duct 2 from the inside air inlet 9. In the evaporator 18, the outside air blown by the first blower 3 flows to the refrigerant uppermost stream portion 18 a side, and the inside air blown by the second blower 4 flows to the refrigerant lowermost stream portion 18 b. Therefore, even under conditions in which the outside air temperature is lower than the inside air temperature, the refrigerant exchanges heat with the inside air having a higher temperature than the outside air in the refrigerant most downstream portion 18b of the evaporator 18, so that the refrigerant absorbs heat more reliably than the inside air. So
The refrigerant flowing out of the outlet pipe 41 of the evaporator 18 always has a proper degree of superheat corresponding to the heat load of the evaporator 18.

Therefore, the temperature sensing cylinder 40a of the temperature type expansion valve 40
Can sense the refrigerant temperature indicating the appropriate degree of superheat, the valve opening of the temperature-type expansion valve 40 becomes an appropriate opening corresponding to the heat load of the evaporator 18, and the appropriate refrigerant flow rate can be set. 18 can be properly secured. Here, if the arrangement of the evaporator 18 in the duct 2 is opposite to that in this example, and the refrigerant flows in the evaporator 18 in FIG. 1 in the opposite direction, the following trouble occurs. . That is, in this case, the refrigerant flowing into the evaporator 18
Heat is exchanged with the inside air blown by the blower 4 and having a higher temperature than the outside air. At that time, if the refrigerant flow rate is short due to any disturbance of the temperature type expansion valve 40, when the inside air and the refrigerant complete the heat exchange, all the refrigerant evaporates and has an excessive degree of superheat. become. here,
If the air blown from the first blower 3 is also inside air having a high temperature, the refrigerant exchanges heat with the inside air to further increase the degree of superheat, and the outlet pipe 41 of the evaporator 18 is heated.
In this case, the degree of superheat can be transmitted to the temperature-sensitive cylinder 40a of the temperature-type expansion valve 40 to increase the degree of opening of the expansion valve (increase the refrigerant flow rate), so that no problem occurs.

However, when the air blown from the first blower 3 is outside air having a lower temperature than the inside air, the refrigerant having a degree of superheat reaching the downstream side of the evaporator exchanges heat with the low-temperature outside air, so that the outside air is cooled. The superheat of the refrigerant at the evaporator outlet is reduced, or reaches a saturation temperature where the superheat is zero, and reaches the temperature-sensitive cylinder 40a. As a result, the temperature sensing cylinder 40a senses the small superheated refrigerant temperature or the superheated zero saturation temperature, and the expansion valve 40 operates not in the direction of increasing the valve opening but in the direction of decreasing the valve opening. As a result, the flow rate of the refrigerant is reduced,
Dehumidifying ability of the steel is reduced. Due to the decrease in the dehumidifying ability of the evaporator 18, the ability to remove the fogging of the window glass during rainy weather in winter or the like is reduced, and the fogging of the window glass cannot be sufficiently removed.

However, in this embodiment, as described above, air in a plurality of temperature fields, ie, inside air and outside air, is simultaneously introduced, and the evaporator 18 exchanges heat between the air in the plurality of temperature fields and the refrigerant. At this time, in the refrigerant most downstream portion 18b of the evaporator 18, the refrigerant exchanges heat with the inside air having a higher temperature than the outside air, so that the refrigerant absorbs heat more reliably than the inside air. The state always has a proper degree of superheat corresponding to the heat load of the evaporator 18, the valve opening of the temperature type expansion valve 40 becomes a proper opening corresponding to the heat load of the evaporator 18, and the appropriate refrigerant flow rate is adjusted. Since it can be set, the dehumidifying ability of the evaporator 18 can be ensured well.

FIG. 2 is a schematic diagram in which the layout of the evaporator 18 and the surrounding duct 2 is summarized for easy understanding. FIG. 2A shows inside air from the second blower 4, and B shows the first blower. Shows fresh air from 3. The arrow of the refrigerant channel 18c in the evaporator 18 indicates the flow direction of the refrigerant. (Second Embodiment) FIG. 3 shows a second embodiment, in which the arrangement direction of the first partition wall 26 is changed from the vertical direction to the horizontal direction in the arrangement layout of FIG. This allows
The most upstream refrigerant portion 18a and the most downstream refrigerant portion 1 of the evaporator 18
8b are located on the side of the air flow path through which the inside air A from the second blower 4 flows. Also in the arrangement layout of the second embodiment, the same operation and effect as in the first embodiment can be exerted by locating the most downstream part 18b of the refrigerant of the evaporator 18 on the side of the air flow path through which the inside air A flows. (Third Embodiment) FIG. 4 shows a third embodiment. In the arrangement layout of FIG. 2, the directions of taking out the refrigerant pipes from the refrigerant most upstream portion 18a and the refrigerant most downstream portion 18b of the evaporator 18 are defined by the inside air A and the outside air B. Is set in a direction parallel to the flow direction of
In the third embodiment shown in FIG.
The direction is set perpendicular to the flow direction of the inside air A and the outside air B. This point is different from the arrangement layout of FIG. 2 only, and the other points are the same. (Fourth Embodiment) FIG. 5 shows a fourth embodiment. In the arrangement layout of FIG. 3, the directions of taking out the refrigerant pipes from the refrigerant upstreammost portion 18a and the refrigerant downstreammost portion 18b of the evaporator 18 are defined by the inside air A and the outside air B. Is set in a direction parallel to the flow direction of
In the fourth embodiment shown in FIG.
The direction is set perpendicular to the flow direction of the inside air A and the outside air B. This point is different from the arrangement layout of FIG. 3 only, and the other points are the same. (Fifth Embodiment) FIG. 6 shows a fifth embodiment. In the arrangement layout of FIG. 3, a single meandering portion is formed between the refrigerant upstreammost portion 18a and the refrigerant downstreammost portion 18b of the evaporator 18. Although connected by the refrigerant flow passage 18c, in the fifth embodiment of FIG. 6, a plurality (three in the illustrated example of FIG. 6) of the refrigerant between the most upstream refrigerant portion 18a and the most downstream refrigerant portion 18b of the evaporator 18 is provided. The connection is made by U-shaped refrigerant flow paths 18d provided in parallel.

The direction in which the refrigerant pipes are taken out from the refrigerant upstream-most portion 18a and the refrigerant downstream-most portion 18b of the evaporator 18 is set to a direction perpendicular to the flow directions of the inside air A and the outside air B.
This is also different from the layout shown in FIG. (Sixth Embodiment) FIG. 7 is a sixth embodiment in which the arrangement direction of the first partition wall 26 is changed from the horizontal direction to the vertical direction in the arrangement layout of FIG. This allows
The most upstream refrigerant portion 18a and the most downstream refrigerant portion 1 of the evaporator 18
8b are both located in both the air flow path through which the inside air A flows from the second blower 4 and the air flow path through which the outside air B flows from the first blower 3.

Therefore, in the sixth embodiment shown in FIG. 7, the sectional area Sa of the air flow path through which the inside air A flows from the second blower 4 is set to the first value.
By setting the cross-sectional area Sb of the air flow path through which the outside air B flows from the blower 3 to be larger than the cross-sectional area Sb (Sa> Sb), the refrigerant flowing through the refrigerant downstreammost portion 18b of the evaporator 18 has a low average temperature. Heat is exchanged with air at a temperature higher than the inside air and closer to the inside air than in the outside air, so that the dehumidifying capacity can be ensured at a low outside air temperature in winter.

In the above-described embodiment, the case where the present invention is applied to a vehicle having an engine (internal combustion engine) 33 as a motor for driving a vehicle has been described. However, a compressor 34 of a refrigeration cycle is used as in an electric vehicle. Of course, the present invention can be similarly applied to the case of driving with an electric motor. In this case, a condenser of a refrigeration cycle (heat pump) may be used as the air heating means instead of the heater core 19 of the hot water heat source.

As the temperature type expansion valve 40, the temperature-sensitive cylinder 4
The expansion mechanism is not limited to a mechanical mechanism using Oa, and it is a matter of course that an electric expansion valve that electrically controls the valve opening by sensing the refrigerant temperature and the refrigerant pressure with an electric sensor can be used.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle air conditioner showing a first embodiment of the present invention.

FIG. 2 is a schematic perspective view showing an arrangement layout in an evaporator portion in FIG. 1;

FIG. 3 is a schematic perspective view of an evaporator according to a second embodiment of the present invention.

FIG. 4 is a schematic perspective view of an evaporator according to a third embodiment of the present invention.

FIG. 5 is a schematic perspective view of an evaporator according to a fourth embodiment of the present invention.

FIG. 6 is a schematic perspective view of an evaporator according to a fifth embodiment of the present invention.

FIG. 7 is a schematic perspective view of an evaporator according to a sixth embodiment of the present invention.

[Explanation of symbols]

2 duct, 3 4, 4 first and 2nd blowers, 18 evaporator, 18a refrigerant uppermost stream portion, 18b refrigerant lowermost stream portion, 1
8c, 18d: refrigerant flow path, 19: heater core, 40: temperature-type expansion valve, 40a: temperature-sensitive cylinder.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-191257 (JP, A) JP-A-5-124426 (JP, A) JP-A-59-9471 (JP, A) JP-A-3-191 247993 (JP, A) JP-A-6-123520 (JP, A) JP-A 63-89812 (JP, U) JP-A 1-63968 (JP, U) JP-A 57-21985 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) B60H 1/32 613 B60H 1/00 101 F25B 39/02 B60H 1/00

Claims (5)

(57) [Claims] 1. Introducing air from a plurality of temperature fields, exchanging the introduced air with refrigerant in an evaporator, and as a decompression means provided at a refrigerant inlet to the evaporator,
In a vehicle air conditioner including a temperature-type expansion valve that adjusts a refrigerant flow rate in accordance with a degree of superheat of a refrigerant at the evaporator outlet, a refrigerant most downstream portion of the evaporator is configured to transmit air from the plurality of temperature fields. An air conditioner for a vehicle, wherein the air conditioner is disposed at a portion where air having a temperature higher than the minimum temperature is introduced. 2. Introducing air from a plurality of temperature fields, exchanging the introduced air with a refrigerant in an evaporator, and as a decompression means provided at a refrigerant inlet to the evaporator,
In the air conditioner for a vehicle including a temperature-type expansion valve that adjusts a refrigerant flow rate in accordance with a degree of superheat of the refrigerant at the evaporator outlet, the refrigerant at the most downstream part of the refrigerant of the evaporator may include a refrigerant from the plurality of temperature fields. The air conditioner for a vehicle, wherein the evaporator is arranged in the flow path of the introduced air so as to exchange heat with air having a temperature higher than a minimum temperature among the air. 3. The air conditioner for a vehicle according to claim 1, wherein the most upstream part and the most downstream part of the refrigerant of the evaporator are connected by one refrigerant flow path. . 4. The method according to claim 1, wherein the most upstream part and the most downstream part of the refrigerant of the evaporator are connected by a plurality of refrigerant passages provided in parallel. Vehicle air conditioners. 5. Introducing air from a plurality of temperature fields, exchanging the introduced air with a refrigerant in an evaporator, and as a pressure reducing means provided at a refrigerant inlet to the evaporator,
In the air conditioner for a vehicle including a temperature-type expansion valve that adjusts a refrigerant flow rate in accordance with a degree of superheating of the refrigerant at the evaporator outlet, a plurality of refrigerant evaporators may be provided between a most upstream part and a most downstream part of the evaporator. The refrigerant at the most downstream portion of the refrigerant of the evaporator is connected to a refrigerant flow path provided in parallel, and among the air from the plurality of temperature fields, the lowest temperature air and the air higher in temperature than the lowest temperature The evaporator is disposed in the flow path of the introduced air so as to exchange heat with both of the air flow path of the air flow path in which the refrigerant and the lowest temperature air in the refrigerant most downstream portion of the evaporator exchange heat. The air-conditioning system for a vehicle, wherein a cross-sectional area of an air flow path for exchanging heat between a refrigerant at a most downstream portion of the refrigerant of the evaporator and air having a temperature higher than the minimum temperature is set larger than a cross-sectional area. .