JP3272663B2 - 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 having a heat pump device for cooling and heating the interior of a vehicle using a refrigerant.

[0002]

2. Description of the Related Art Conventionally, an air conditioner using a heat pump device has been known as an air conditioner for a vehicle. FIG. 6 is a schematic block diagram of a conventional vehicle air conditioner using a heat pump device. The conventional air conditioner includes a first indoor heat exchanger 31 and a second indoor heat exchanger 33 for exchanging heat between air and a refrigerant in a passenger compartment, and a compressor 11 for compressing the refrigerant.
And an outdoor heat exchanger 3 for exchanging heat between air and refrigerant outside the vehicle compartment
5, a first expansion device 37 and a second expansion device 39 for depressurizing the refrigerant, and an on-off valve 4 for switching the circulation path of the refrigerant.
1 and 42, and a four-way valve 43 for switching the circulation direction of the refrigerant. These are connected by a pipe 23, and the refrigerant for heat exchange and the lubricating oil of the compressor circulate in the pipe 23. Further, the first indoor heat exchanger 31 and the second indoor heat exchanger 33 are
7 and the mixing damper 29 are disposed in the air conditioning duct 25. The air conditioning duct 25 is connected to an outlet in the vehicle compartment, and the air generated by the blower 27 is heated or cooled by the indoor heat exchangers 31 and 33 and then sent out into the vehicle compartment. The mix damper 29 adjusts the flow rate and temperature of the air blown into the vehicle interior according to the opening degree.

In such an air conditioner, when heating is performed, the refrigerant compressed by the compressor 11 radiates heat in the first indoor heat exchanger 31 and the second indoor heat exchanger 33. Thereafter, the refrigerant absorbs heat in the outdoor heat exchanger 35 and returns to the compressor 11. At this time, the wind blown by the blower 27 in the air conditioning duct 25 is heated when passing through the first and second indoor heat exchangers 31 and 33, sent out into the vehicle interior, and used for heating.

[0004]

In the above-described method, the refrigerant exchanges heat with the air in the passenger compartment and then exchanges heat with the outside air. For this reason, when the temperature of the outside air is very low (for example, −18 ° C.), the suction pressure in the compressor 11 decreases, the compression ratio of the compressor 11 increases, the refrigerant circulation amount decreases, and the heating capacity decreases. There is a problem of lowering. In addition, when the outside air temperature is low, there is a problem that the outdoor heat exchanger 35 is frosted and the heating capacity is reduced accordingly. Generally, when the outdoor heat exchanger 35 is frosted, control for removing frost such as reversing the refrigerating cycle is required, and there is a problem that sufficient heating cannot be obtained during this time. This becomes more serious as the outside air temperature is lower.

Further, in the case of heating with an air conditioner as shown in FIG. 6, there is a problem that the vehicle window is condensed when the indoor humidity is high such as in winter or rainy weather. Therefore, it is necessary to perform dehumidifying heating. In this case, in the air conditioner, the expansion devices 37 and 39, the four-way valve 43, and the on-off valves 41 and 42 are arranged as shown in FIG.
And a new circulation path is formed.
At this time, the circulation direction of the refrigerant is reversed because the four-way valve 43 is switched.

Accordingly, the refrigerant compressed by the compressor 11 and heated to a high temperature and a high pressure releases heat in the second indoor heat exchanger 33 and is decompressed by the first expansion device 37, and then the first indoor heat exchanger After absorbing heat at 31, the process returns to the compressor 11. In other words, the air in the passenger compartment is first supplied to the first indoor heat exchanger 3.
After being dehumidified in step 1, it is heated in the second indoor heat exchanger 33, so that dehumidification and heating can be performed.

However, in the dehumidifying and heating control described above, a closed path, that is, a closed cycle is formed in the outdoor heat exchanger 35 as shown in FIG. During this closed cycle, the refrigerant and the lubricating oil stay. For this reason, since the amounts of the refrigerant and the lubricating oil in the entire air conditioner are constant, the amounts of the refrigerant and the lubricating oil flowing in the circulation path at the time of dehumidifying and heating decrease. This decrease in the amount of lubricating oil causes a decrease in the reliability of the operation of the compressor, and a decrease in the amount of refrigerant causes a decrease in the performance as a refrigeration cycle.

Further, as a vehicle heating device, there is known a hot water type heating device for heating air for temperature control using cooling water (hot water) of an engine. With recent high efficiency engines,
When the outside air temperature is low (−20 ° C.), the temperature of the engine cooling water does not rise sufficiently. For this reason, in a vehicle equipped with a high-efficiency engine, there is a problem that the heating capacity of the hot-water heating device is insufficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an air conditioner suitable for an automobile which does not cause a decrease in heating capacity during heating at extremely low temperatures or during dehumidifying heating. And

[0010]

A first vehicle air conditioner according to the present invention comprises a first heat exchange means for exchanging heat between a refrigerant and vehicle interior air, and a first heat exchange means. In a vehicle air conditioner for performing air conditioning in a vehicle cabin by a heat pump unit including a second heat exchange unit that performs heat exchange on the refrigerant that has undergone heat exchange with the refrigerant, the second heat exchange unit is connected to the refrigerant. It is constituted by a brine heat exchange means for exchanging heat with the brine. With this configuration, heat exchange between the outside air and the refrigerant is prevented, and the heating capacity is not affected by the outside air temperature.

[0011] A second vehicle air conditioner according to the present invention includes a compressor for compressing refrigerant, indoor heat exchange means for exchanging heat between the compressed refrigerant and vehicle interior air, and an indoor heat exchange device. Refrigerant after heat exchange by the means, brine heat exchange means for exchanging heat between the brine, first decompression means provided upstream of the brine heat exchange means in the flow of the refrigerant, and A second pressure reducing means provided downstream of the brine heat exchanging means. During the heating operation, the refrigerant is depressurized by the first decompression means,
Does not decompress the refrigerant. During cooling operation,
The refrigerant is depressurized by the second depressurizing means without depressurizing the refrigerant by the first depressurizing means.

[0012] The second vehicle air conditioner may further include brine cooling means for cooling brine used for heat exchange by the brine heat exchange means during cooling operation. The brine cooled by the brine cooling means cools the refrigerant, thereby increasing the cooling capacity. Alternatively, in the second vehicle air conditioner, an auxiliary heat exchange unit that cools the refrigerant during the cooling operation may be provided between the first pressure reducing unit and the second pressure reducing unit.

The first and second vehicle air conditioners may further include hot water heat exchange means for heating the air in the passenger compartment by exchanging heat with hot water during a heating operation. At this time, the hot water and the brine may be cooling water for cooling a vehicle engine.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a vehicle air conditioner according to the present invention will be described with reference to the accompanying drawings. The air conditioner for a vehicle according to the present embodiment, in an air conditioner using a heat pump device, is arranged outside the vehicle compartment to exchange heat between the outside air and the refrigerant in order to prevent direct heat exchange between the outside air and the refrigerant. Instead of the outdoor heat exchanger to be performed, a brine heat exchanger that is a heat exchanger that performs heat exchange between the refrigerant and another medium (brine) is provided.

<First Embodiment> FIG. 1 is a schematic block diagram of a vehicle air conditioner according to a first embodiment. The vehicle air conditioner includes a compressor 11 for compressing the refrigerant, an indoor radiator 13 for exchanging heat between the refrigerant and the air in the vehicle to heat the air in the vehicle, a first expansion device 15 for decompressing the refrigerant,
Brine heat exchanger 17 for exchanging heat between refrigerant and brine
, A second expansion device 19 for reducing the pressure of the refrigerant, and an indoor cooler 21 for exchanging heat between the refrigerant and the vehicle interior air to generate dehumidification or cool air. The refrigerant circulates through the pipe 23.
The indoor radiator 13 and the indoor cooler 21 are connected to an air conditioning duct 25.
The air conditioning duct 25 has a blower 27 for sending out hot / cold air for air conditioning, and a mix damper for adjusting the amount and temperature of the air passing through the indoor radiator 13. 29 are provided. The air conditioning duct 25 is connected to a predetermined outlet in the vehicle compartment, and air whose temperature is adjusted in the air conditioning duct 25 is sent out from the outlet into the vehicle interior.

The brine heat exchanger 17 exchanges heat between the refrigerant and brine as a heat medium, and the brine after the heat exchange with the refrigerant is heated or cooled by a predetermined heating device or cooling device. Here, the brine is preferably a fluid such as ethylene glycol, water, or an antifreeze or oil. The circulation of the brine to the brine heat exchanger 17 is performed by the pump 30. FIG. 1 shows a state of the vehicle air conditioner at the time of heating. Here, hot water heated by a hot water heater 18a is used as brine. Further, the cooling water of the engine may be used as the brine. Such a brine heat exchanger 1
By using 7, it is possible to heat the refrigerant during heating by a method that is isolated from the outside air. FIG. 2 shows a state of the vehicle air conditioner during cooling, in which the brine is cooled by the cooler 18b. That is,
In the present embodiment, the brine is switched between heating and cooling.

Also, the first and second expansion devices 15, 1
Reference numeral 9 includes capillary tubes 15a and 19a and solenoid valves 15b and 19b. Refrigerant to expansion device 1
When the pressure is reduced at 5, 19, the solenoid valves 15b, 1
By closing 9b, the capillary tubes 15a, 19
Let all the refrigerant flow through a. When the pressure of the refrigerant is not reduced, the solenoid valves 15b and 19b are fully opened to form a bypass path bypassing the capillary tubes 15a and 19a, and most of the refrigerant passes through the bypass path. At this time, the expansion devices 15, 1
The refrigerant passing through 9 passes as it is without decompression. In addition, these expansion devices 15 and 19 are configured by an electric expansion valve or a mechanical expansion valve whose opening degree can be adjusted.
As a control corresponding to the release of the solenoid valves 15b and 19b, the opening degree of the electric expansion valve and the mechanical expansion valve is set to a fully opened state or a state close to it, and the capillary tube 15 is opened.
As the control corresponding to the use of a and 19a, the opening may be controlled to an appropriate degree of reduced pressure.

In the vehicle air conditioner thus constructed, the air heated by the indoor radiator 13 or the air cooled by the indoor cooler 21 passes through the air conditioning duct 25 and passes through the vehicle through a predetermined outlet. It is blown out into the room. At this time, the temperature of the air blown into the vehicle interior is adjusted by controlling the temperature of the refrigerant, the opening degree of the mix damper 29, the air volume, and the like.

The operation of the air conditioner during heating will be described below with reference to FIG. During heating, the first expansion device 15 is controlled so that the refrigerant passing therethrough is depressurized. Second
Is controlled to be fully open. Mix damper 2
The opening of 9 is controlled so that the wind blown from the blower 27 passes through the indoor radiator 13.

By controlling the expansion devices 15, 19 and the mix damper 29 in this way, the compressor 11
The refrigerant, which has been compressed at high temperature and high pressure, is supplied to the indoor radiator 1
In step 3, heat is released, and the air from the blower 27 is heated. Thereafter, the refrigerant is decompressed in the first expansion device 15, performs heat absorption by exchanging heat with the brine in the brine heat exchanger 17, passes through the second expansion device 19 that is fully open, and further passes through the indoor cooler 21. It absorbs heat and dehumidifies the wind from the blower 27. That is, the air sent from the blower 27 is dehumidified by the indoor cooler 21, heated by the indoor radiator 13, and sent out into the vehicle interior. For this reason, dehumidification heating becomes possible.

At this time, as described above, in the brine heat exchanger 17, since the refrigerant is heated while being shut off from the outside air, dehumidifying heating that is not affected by the outside air temperature can be performed.

Next, the operation during cooling will be described with reference to FIG. During cooling, the first expansion device 15 is controlled to be fully opened. The second expansion device 19 is controlled so that the refrigerant passing therethrough is depressurized. The opening of the mix damper 29 is
In order that the air does not pass through the indoor radiator 13, that is,
The blast is controlled so as not to be heated.

At this time, the refrigerant which has been compressed by the compressor 11 and has become high temperature and high pressure passes through the indoor radiator 13, but does not radiate heat because the mix damper 29 is closed with respect to the indoor radiator 13. Pass through. Thereafter, the refrigerant passes through the first expansion device 15 which is fully open, radiates heat in the brine heat exchanger 17, is decompressed in the second expansion device 19, and absorbs heat in the indoor cooler 21. That is, the blower 27
Is cooled by the indoor cooler 21, and the cooled air is blown into the vehicle compartment without passing through the indoor radiator 13. Thereby, cooling of the vehicle interior is performed. At this time, the brine is cooled by the cooler 18b. Further, in this case, by adjusting the opening of the mix damper 29 so as to heat the indoor radiator 13 by passing the wind, the dehumidifying heating by a method different from the above-described dehumidifying heating becomes possible.

As described above, in the air conditioner of the present embodiment, in the air conditioner using the heat pump device, instead of the conventional outdoor heat exchanger disposed outside the room,
Install a brine heat exchanger that performs heat exchange with the outside air,
At the time of heating, by heating the refrigerant in the brine heat exchanger, it is possible to prevent a decrease in the suction capacity at extremely low temperatures, a decrease in the heating capacity due to frost formation, etc., and to perform heating and dehumidifying heating that are not affected by the outside air temperature. . At this time, since no closed cycle is formed, the reliability and performance of the compressor are not reduced. In addition, since it is not necessary to consider heat exchange with the outside air, a layout design that is not restricted to the installation location of the heat exchanger can be made.

In this embodiment, in order to control the temperature of the indoor air, the indoor radiator and the indoor cooler are provided on the indoor side.
An example with two heat exchangers is shown. The air conditioner of the present embodiment is an air conditioner using a heat pump device,
Since the heat exchange between the refrigerant and the outside air is prevented, even when only one heat exchanger is provided on the indoor side, the same as described above by using the brine heat exchanger as the outdoor heat exchanger. The effect is obtained.

<Embodiment 2> The vehicle air conditioner of the present embodiment differs from the vehicle air conditioner of Embodiment 1 in that, in order to increase the heating capacity, in addition to a heat pump device, hot water for heating using hot water is used. Equipped with a heating device. Furthermore, the vehicle air conditioner of the present embodiment includes an auxiliary heat exchanger for cooling brine during cooling, and increases the cooling capacity by cooling the refrigerant with brine more strongly.

FIG. 3 is a schematic block diagram of a vehicle air conditioner according to the second embodiment. In the vehicle air conditioner shown in FIG.
In the vehicle air conditioner according to the first embodiment, an engine 18c is used instead of the hot water heater 18a as a brine heating unit. If necessary, a hot water heater or a combination of a hot water heater and an engine may be used. That is, the cooling water of the engine is used as the brine. The vehicle air conditioner includes a heater core 35 for exchanging heat with warm water in an air conditioning duct 25. Cooling water (hot water) is supplied to the heater core 35 by a pump 40 from the engine 18c via a pipe 36. Hot water heating is performed by the heater core 35 and the engine. The supply of hot water to the heater core 35 is controlled by a solenoid valve 38. The heater core 35 and the indoor radiator 13 may be integrated. The vehicle air conditioner includes a brine heat exchanger 1
7, an auxiliary heat exchanger 31 connected in parallel with an engine (hereinafter, referred to as "brine heater") 18c;
A blower 33 for air cooling the auxiliary heat exchanger 31; The auxiliary heat exchanger 31 and the blower 33 cool the brine. One of the paths connecting the brine heat exchanger 17 and the brine heater 18c is provided with a solenoid valve 37a, and the other of the path connecting the brine heat exchanger 17 and the auxiliary heat exchanger 31 is provided with a solenoid valve 37b. ing. Here, one three-way valve may be provided instead of the solenoid valves 37a and 37b, and the switching of the brine circulation path may be performed by this. The auxiliary heat exchanger 31 may also serve as a radiator for cooling the engine, or may be integrated. In the present embodiment, the circuit on the refrigerant side is the same as that of the first embodiment.

The operation of the vehicle air conditioner thus configured will be described below. The operation of the circuit on the refrigerant side, that is, the operation on the side of the heat pump device in this embodiment is the same as that of the first embodiment, and therefore only the operation of the hot water heating and the circuit on the brine side will be described.

The operation during heating will be described with reference to FIG. During heating, the solenoid valve 37a is opened and the solenoid valve 3
7b is closed. The solenoid valve 38 is opened when the brine reaches a predetermined temperature or when a predetermined time has elapsed from the start of operation. Pump 3
0 and 40 are turned on (operated). Thereby, the brine circulates between the brine heat exchanger 17 and the brine heater 18c, is heated by the brine heater 18c, and heats the refrigerant by the brine heat exchanger 17. Therefore, the air in the air conditioning duct 25 is heated by the indoor heat exchanger 13, and the refrigerant having a relatively large amount of heat absorbed by the brine heat exchanger 17 flows to the indoor cooler 21. With 21, the air flowing through the air-conditioning duct 25 is less cooled, and a further heating effect can be expected. At the same time, warm water circulates through the heater core 35. Thus, the air in the air conditioning duct 25 can be heated by the heater core 35 in addition to the heat pump heating using the refrigerant.

As described above, in the vehicle air conditioner of this embodiment, in addition to heat pump heating, hot water heating can be performed, so that a high heating capacity can be obtained. In this case, heat pump heating and hot water heating can be switched and used. For example, immediately after starting the car engine,
Since the rising speed of the hot water temperature is slow, it is also possible to perform heat pump heating with a little dehumidification during this time, and switch to hot water heating when the hot water temperature reaches a predetermined temperature.
Further, in order to accelerate the rise of the room temperature, it is also possible to adopt a structure in which air does not flow through the indoor cooler 21 and heat the room only with the indoor radiator 13. Such control is particularly effective for a vehicle equipped with a high-efficiency engine in which the temperature of hot water hardly increases at the time of starting.

FIG. 4 is a diagram for explaining the operation of the vehicle air conditioner during cooling. During cooling, the solenoid valves 37a, 3a
8 is closed and the solenoid valve 37b is opened. Further, the pump 30 is turned on and the pump 40 is turned off (stopped).
Thereby, the brine circulates between the brine heat exchanger 17 and the auxiliary heat exchanger 31. Hot water does not circulate through the heater core 35. The brine is cooled by the blower 33 in the auxiliary heat exchanger 31, and the refrigerant is cooled in the brine heat exchanger 17 by the cooled brine. The cooled refrigerant cools the air in the air conditioning duct 25 in the indoor cooler 21 to cool the vehicle interior. Thus, in the vehicle air conditioner of the present embodiment, at the time of cooling, the brine is cooled by the auxiliary heat exchanger 31 (and the blower 33), and the refrigerant is cooled by the cooled brine. Thereby, the heat absorbing capacity (radiation capacity) of the refrigerant is increased, so that the cooling capacity can be improved.

<Third Embodiment> In the second embodiment, the auxiliary heat exchanger 31 for cooling the brine is provided on the brine circuit side in order to enhance the cooling capacity. However, in the present embodiment, this auxiliary heat exchange is performed. The cooling device was provided on the refrigerant circuit side to cool the refrigerant during cooling. Thereby, the heat radiation capacity of the refrigerant is increased, and the cooling capacity is enhanced.

FIG. 5 is a schematic block diagram of a vehicle air conditioner according to the third embodiment. The vehicle air conditioner of the present embodiment differs from the vehicle air conditioner of the second embodiment in that the auxiliary heat exchanger 31 (and the blower 33) is not used, but instead the auxiliary heat exchanger 41 and the auxiliary heat exchanger 41 are used. And a blower 43 for air cooling are provided between the brine heat exchanger 17 and the second expansion device 19. Further, a bypass path for bypassing the auxiliary heat exchanger 41 and a solenoid valve 39b for controlling the flow of refrigerant into the bypass path are provided. Other configurations are the same as those in the second embodiment. The operation of the auxiliary heat exchanger 41 will be described below.

During cooling, the pumps 30 and 40 are turned off, the solenoid valves 37a, 38 and 39b are closed, and the refrigerant passes through the auxiliary heat exchanger 41. At this time, the refrigerant is air-cooled by the blower 43. Thereby, the heat absorption capacity of the refrigerant in the indoor cooler 21 is increased, and the cooling capacity is improved.

On the other hand, during heating, the pumps 30, 4
0 is turned on, the solenoid valves 37a, 38, 39b are opened, and at the same time the blower 43 is stopped. After the refrigerant is heated in the brine heat exchanger 17, part of the refrigerant passes through the bypass path and the auxiliary heat exchanger 41 due to the flow resistance, but most of the refrigerant flows through the solenoid valve 39b, and the second expansion device 19. Since the blower 43 is stopped, the auxiliary heat exchanger 41 does not exchange heat. Other operations are the same as those in the second embodiment.

As described above, in the vehicle air conditioner of this embodiment, the cooling capacity is improved by cooling the refrigerant by the auxiliary heat exchanger 41 during cooling.

[0037]

According to the air conditioner for a vehicle of the present invention, a heat pump operation can be performed by using a brine heat exchanger during heating without exchanging heat of the refrigerant with the outside air. Thus, the air conditioner can be operated without being affected by the outside air temperature without causing a decrease in the heating capacity at the time of heating at an extremely low temperature and at the time of dehumidifying heating.

Further, according to the vehicle air conditioner, the refrigerant can be more strongly cooled before the refrigerant flows into the indoor heat exchange means at the time of cooling, so that the cooling capacity can be increased.

Further, according to the vehicle air conditioner, in addition to heating by a heat pump operation, hot water heating using hot water such as engine cooling water can be performed. Thereby, a high heating capacity can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a vehicle air conditioner according to a first embodiment during a heating operation.

FIG. 2 is a schematic block diagram of the vehicle air conditioner according to the first embodiment during a cooling operation.

FIG. 3 is a schematic block diagram during a heating operation of the vehicle air conditioner according to the second embodiment.

FIG. 4 is a schematic block diagram of the vehicle air conditioner according to the second embodiment during a cooling operation.

FIG. 5 is a schematic block diagram of a vehicle air conditioner according to a third embodiment.

FIG. 6 is a schematic block diagram of a conventional vehicle air conditioner during a heating operation.

FIG. 7 is a schematic block diagram of a conventional vehicle air conditioner during a dehumidifying and heating operation.

[Explanation of symbols]

 Reference Signs List 11 compressor 13 indoor radiator 15 first expansion device 17 brine heat exchanger 18c brine heater (engine) 19 second expansion device 21 indoor cooler 23 piping 25 air conditioning duct 27 blower 29 mix damper 31, 41 auxiliary heat Exchanger 35 heater core.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-240266 (JP, A) JP-A-5-221233 (JP, A) JP-A-9-254639 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B60H 1/22 B60H 1/32

Claims (2)

(57) [Claims] 1. A compressor for compressing a refrigerant, indoor heat exchange means for exchanging heat between the compressed refrigerant and vehicle interior air, refrigerant after heat exchange by the indoor heat exchange means, and brine. A brine heat exchange means for exchanging heat between the first heat exchanger, a first pressure reducing means provided upstream of the brine heat exchange means in the flow of the refrigerant, and a second pressure reduction means provided downstream of the brine heat exchange means in the flow of the refrigerant. A refrigeration cycle annularly connected to the second pressure reducing means, a heater provided separately from the engine, for heating brine used for heat exchange by the brine heat exchange means during a heating operation, and the brine heat exchange during a cooling operation. A brine cooling means for cooling the brine used for heat exchange by the means. During the heating operation, the refrigerant is depressurized by the first decompression means, and the refrigerant is not depressurized by the second decompression means. Using the brine heated by the heater in the brine heat exchanging means to absorb heat of the refrigerant, and in the cooling operation, the first decompression means does not decompress the refrigerant, and the second decompression means decompresses the refrigerant. An air conditioner for a vehicle, wherein a refrigerant is radiated by using the brine cooled by the brine cooling unit by the brine heat exchange unit. 2. The air conditioner for a vehicle according to claim 1, wherein the brine is hot water.