JPH11170857A - Heat pump type automobile air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump type automobile air conditioner formed so as to compensate insufficiency of heating performance at heating time by using a refrigerant given a high temperature and high pressure by a compressor. SOLUTION: In a cooling cycle of a heat pump type automobile air conditioner, a bypass circuit 30 is provided, wherein a refrigerant flowing out from an auxiliary internal heat exchanger Ea at heating time, bypassing a second flow regulating valve 5b and a main internal heat exchanger Eb, is fed back to a compressor 2. In this bypass circuit 30, a refrigerant expansion member 32 and a sub-heat exchanger 33 are provided, also the sub-heat exchanger 33 is arranged outside a unit case 10, in the sub-heat exchanger 33, a refrigerant flowing out from the auxiliary internal heat exchanger Ea is heated by the outside air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type vehicle air conditioner for cooling and heating the interior of a vehicle.

[0002]

2. Description of the Related Art Generally, in a cooling cycle of an air conditioner for an automobile, a refrigerant discharged from a compressor is provided with an external heat exchanger (functioning as a condenser during cooling), a refrigerant expansion member and an internal heat exchanger (evaporator during cooling). It is well known that the compressor is fed back to the compressor.

[0003] An air conditioner for an automobile incorporating such a cooling cycle, for example, as shown in FIG. 3, is provided between an intake unit 11 provided at an end portion of a unit case 10 and vehicle interior air (inside air). Outdoor air (outside air) is selectively introduced into the air passage 10f, and the air is conditioned and blown out toward the vehicle interior.

In this case, the engine 1 is located in the air passage 10f.
A heater core 13 into which engine cooling water (indicated by a broken line in the drawing) heated by the heater is introduced through a hot water cock 12;
The refrigerant discharged from the compressor 2 is supplied to the external heat exchanger 3,
An internal heat exchanger E that flows through the liquid tank 4 and the refrigerant expansion member 5, and a mix door 15 that adjusts a ratio of the air cooled by the internal heat exchanger E to pass through the heater core 13 and the bypass passage 14. Is provided.

The cool air that has been cooled and dehumidified by the internal heat exchanger E is branched by the mix door 15 into the heater core 13 and the bypass passage 14, and the high-temperature air heated by the heater core 13 passes through the bypass passage. 1
After being mixed with the low-temperature air passing through the heater core 13 in the downstream area of the heater core 13 and reaching a predetermined temperature, the air distribution door 16 is used to move the air from the predetermined outlets (vent port 17v, differential port 17d, foot port 17f) to the front of the passenger compartment. It is blown out toward. In the figure, reference numeral "F" indicates a fan, and "M" indicates a fan motor.

[0006]

However, when the air conditioner for a vehicle performs a heating operation, for example, when the outside air temperature is low, such as in the morning of winter, the temperature of the engine cooling water is low at the time of starting, and the comfort is low. Heater core 1 as a guide for
Heating up slowly until the temperature of the air blown from 3 becomes about 50 ° C. In addition, the temperature of the refrigerant itself is not agile, so that warm air is blown out at the same time as the operation starts,
There is a possibility that the so-called immediate heating property is insufficient, and the heating performance tends to be insufficient. In particular, when the engine is idling or under a low load, the temperature of the engine cooling water is as low as about 40 ° C. or less, and a sufficient cooling water temperature cannot be obtained, and there is a tendency that both the immediate warming property and the heating performance are insufficient.

[0007] The present invention has been made in view of such problems of the prior art, and compensates for insufficient heating performance during heating by using a refrigerant whose temperature and pressure are made high by a compressor, thereby improving immediate heating and heating performance. It is an object of the present invention to provide a heat pump type air conditioner for a vehicle which is designed to be enhanced.

[0008]

In order to achieve the above-mentioned object, a heat pump type air conditioner for a vehicle according to the present invention uses a refrigerant discharged from a compressor to an external heat exchanger, a refrigerant expansion member and an internal heat exchanger. A cooling cycle for returning to the compressor through a heat exchanger, wherein the internal heat exchanger is disposed in an air passage of a unit case, wherein the refrigerant expansion member and the internal heat exchanger include 1 The flow control valve, the auxiliary internal heat exchanger, the second flow control valve, and the main internal heat exchanger are connected in series in this order, and the auxiliary internal heat exchanger and the main internal heat exchanger are connected to the air passage. The auxiliary internal heat exchanger and the main internal heat exchanger are respectively opened by adjusting the opening degrees of the first flow control valve and the second flow control valve. In addition, the cooling cycle may be configured such that the refrigerant flowing out of the auxiliary internal heat exchanger during heating returns to the compressor by bypassing the second flow control valve and the main internal heat exchanger. A bypass circuit having a refrigerant expansion member and a sub heat exchanger provided in the bypass circuit and the sub heat exchanger is disposed outside the unit case, and the sub heat exchanger is used to separate the auxiliary internal heat exchanger from the auxiliary internal heat exchanger. The refrigerant flowing out is heated by outside air.

In the air conditioner for an automobile having such a configuration,
At the time of heating start, the air is heated not only by the heater core through which the engine cooling water flows but also by the auxiliary internal heat exchanger through which the high-temperature and high-pressure refrigerant flows, so that the heating performance can be dramatically improved.

Further, in the sub heat exchanger disposed outside the unit case, the refrigerant flowing out of the auxiliary internal heat exchanger and adiabatically expanded by the refrigerant expansion member is heated by the outside air, so that the heat discharged from the air blown into the vehicle compartment is heated. Is not pumped up, and higher heating performance can be exhibited.

By adjusting the opening of the first or second flow control valve, the auxiliary internal heat exchanger or the main internal heat exchanger can be used as a condenser or an evaporator with a simple circuit configuration. Thus, it is possible to prevent dehumidifying heating and excessive cooling, to create a so-called dry air conditioner, perform various operations, and further improve cooling performance.

It is preferable to further provide a bypass circuit in which the refrigerant discharged from the compressor during heating flows by bypassing the external heat exchanger and is guided to the internal heat exchanger. With this configuration, during the heating operation, the high-temperature refrigerant flows by bypassing the large-capacity external heat exchanger, so that it easily flows into the auxiliary internal heat exchanger, and the heating performance is improved.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are schematic configuration diagrams illustrating an embodiment of a heat pump type air conditioner for a vehicle according to the present invention. FIG. 1 illustrates a state during a heating operation, and FIG. 2 illustrates a state during a cooling operation. Is shown. Note that members common to those in FIG. 3 are denoted by the same reference numerals and description thereof is partially omitted. In the drawing, white arrows indicate the flow of air, solid arrows indicate the flow of refrigerant, and broken arrows indicate the flow of engine cooling water.

The heat pump type air conditioner for a vehicle according to the present embodiment is configured as shown in FIG. 1. In general, the refrigerant discharged from the compressor 2 is supplied to an external heat exchanger 3, a liquid tank, and the like. 4. A cooling cycle for returning to the compressor 2 via the refrigerant expansion member 5 and the internal heat exchanger E is configured.

On the high pressure side of the cooling cycle, a bypass circuit B and two check valves Vc are provided so that the refrigerant discharged from the compressor 2 at the time of heating flows by bypassing the external heat exchanger 3. I have.

On the other hand, a pair of refrigerant expansion members 5 and internal heat exchangers E are provided on the low pressure side. That is, the first flow control valve 5a which is in the open state and the throttle state,
The auxiliary internal heat exchanger Ea, the second flow rate control valve 5b composed of a temperature control type expansion valve, and the main internal heat exchanger Eb are connected in series in this order.

Here, the first flow control valve 5a is opened (substantially fully open) and throttled (not completely closed) by turning on a switch (not shown) for operating the auxiliary internal heat exchanger. (A state in which the refrigerant passage is slightly open), which functions as a so-called solenoid valve.

The temperature control type expansion valve constituting the second flow rate control valve 5b belongs to the public domain, and a detailed description is omitted.
The outlet refrigerant temperature of the main internal heat exchanger Eb is sensed by a temperature-sensitive cylinder, the valve opening is adjusted with high precision, and the refrigerant flows at a desired flow rate. That is, the main internal heat exchanger E
When the outlet refrigerant temperature of b decreases, the opening degree is reduced to restrict the flow rate, and when the outlet refrigerant temperature increases, the opening degree is increased and a large amount of refrigerant flows, whereby the evaporation temperature of the refrigerant in the main internal heat exchanger Eb is always The temperature difference of the outlet refrigerant of the internal heat exchanger Eb is made constant.

As described above, by using the switching valve capable of selecting the open state and the throttle state in combination with the temperature type expansion valve, the dehumidifying heating can be reliably performed as described later, and the heating operation is performed by circulating the inside air. Even so, the windshield does not fog and driving safety is improved. In addition, since the opening of the temperature type expansion valve is controlled by the temperature of the refrigerant on the outlet side of the main internal heat exchanger, accurate refrigerant control is possible.

The above-mentioned components are provided in the unit case 10.
In the air passage 10f, the main internal heat is supplied from the upstream side in the flow direction (indicated by a white arrow) of the air introduced from an intake unit 11 which is an air introduction unit having an intake door (not shown) and a blower motor M. The heat exchanger Eb, the auxiliary internal heat exchanger Ea, the air mix door 15, and the heater core 13 are arranged in this order. The auxiliary internal heat exchanger Ea and the main internal heat exchanger Eb are mutually connected in the air passage 10f. They are arranged close to each other. Various air outlets 17 (for example, a differential air outlet 17d, a vent air outlet 17) through which conditioned air is blown out toward a predetermined portion in the vehicle compartment are provided on the outlet side of the air passage 10f.
v, foot outlet 17f) is provided.

In particular, in the cooling cycle of the present embodiment, the refrigerant flowing out of the auxiliary internal heat exchanger Ea during heating returns to the compressor 2 by bypassing the second flow control valve 5b and the main internal heat exchanger Eb. And a bypass circuit 30 for performing the operation. Auxiliary internal heat exchanger Ea and second flow control valve 5b
A flow path switching valve 31 for selectively flowing the refrigerant flowing out of the auxiliary internal heat exchanger Ea toward the bypass circuit 30 or the second flow rate control valve 5b is provided on the way of the refrigerant conduit between the first and second flow paths. Have been. In the bypass circuit 30, a refrigerant expansion member 31 and a sub heat exchanger 33 are provided. The refrigerant expansion member is composed of, for example, a capillary tube 32 having a fixed opening, and a sub heat exchanger 33.
Functions as an evaporator.

The sub heat exchanger 33 is provided outside the unit case 10, and the refrigerant flowing out of the auxiliary internal heat exchanger Ea adiabatically expands in the capillary tube 32, and then passes through the sub heat exchanger 33 and the compressor. It is to be returned to 2. The refrigerant flowing inside the sub heat exchanger 33 is blown into the air passage 10
f, instead of drawing heat from the air flowing through the inside of the unit case 10,
, Thereby achieving higher heating performance.

Further, the cooling cycle of the present embodiment has a return circuit R for recovering the refrigerant stored in the external heat exchanger 3 to the compressor 2 at the time of starting heating. Normally, the refrigerant does not return to the compressor after the operation is stopped, and often lays in each component constituting the cooling cycle,
There is not much in the compressor 2. If the compressor 2 is operated in this state and the heating operation is started, the operation cannot be performed using a large amount of refrigerant, and the deterioration of the heating performance cannot be denied. Therefore, at the start of operation, it is preferable to temporarily return the refrigerant lying inside the external heat exchanger 3 and the like to the compressor 2 once.

For this purpose, a four-way valve 6 is provided between the compressor 2 and the external heat exchanger 3, and a return circuit R connected to the external heat exchanger 3 and the compressor 2 via the four-way valve 6 is formed. The refrigerant lying inside the external heat exchanger 3 and the like through the circuit R is guided to the compressor 2 and collected.

Here, the four-way valve 6 is provided with one inlet port Pi and three outlet ports Po in the closed case 7,
In the closed case 7, two of the three outlet ports Po are provided.
A slide member S communicating with the two outlet ports Po is provided, and an outlet port Po other than the outlet port Po selected by the slide member S is configured to communicate with the inlet port Pi. Therefore, the outlet port P communicated with the inlet port Pi depending on the position where the slide member S is set.
o will be selected.

Therefore, when the four-way valve 6 is set to the state shown in FIG. 1 at the start of the heating operation, the suction side of the compressor 2 and the external heat exchanger 3 are communicated via the return circuit R. The stagnation refrigerant in the external heat exchanger 3 is recovered by the compressor 2 due to the suction force of the compressor 2, and the amount of refrigerant discharged from the compressor 2 increases,
A decrease in heating performance is prevented.

Next, the operation of the embodiment will be described. << Heating operation >> When the outside air temperature is low (for example, about -10 ° C to + 5 ° C) at the start of the heating operation, or when the engine cooling water temperature is used for heating, such as immediately after starting the engine, when the engine is under a low load, or when idling. If it is too low, the four-way valve 6 is operated as shown in FIG. 1 to recover the refrigerant, and the switch for operating the auxiliary internal heat exchanger Ea is turned on to open the first flow control valve 5a. I do. Further, the switch for operating the flow path switching valve 31 is turned on to open the bypass circuit 30.

Since the refrigerant stored in the external heat exchanger 3 is recovered, a large amount of high-temperature and high-pressure refrigerant is discharged from the compressor 2, and this refrigerant is supplied to the bypass circuit B, the liquid tank 4, It flows with one flow control valve 5a.
The liquid tank 4 in this case is simply
Only one container.

Therefore, the auxiliary internal heat exchanger Ea includes:
Since the refrigerant in the high-temperature and high-pressure state bypassing the large-capacity external heat exchanger 3 flows into the auxiliary internal heat exchanger Ea as it is, the air passing therethrough is heated, and the heating performance is improved. Here, the refrigerant is condensed to some extent.

The refrigerant flowing out of the auxiliary internal heat exchanger Ea is guided from the flow path switching valve 31 to the bypass circuit 30, and the flow rate is restricted by the capillary tube 32, where it is adiabatically expanded to become a low-temperature low-pressure refrigerant. Further, the flowing-down refrigerant draws heat from the outside air outside the unit case 10 while flowing through the sub heat exchanger 33.

Therefore, the air sent from the intake unit 11 is not cooled by the main internal heat exchanger Eb, but is heated by the auxiliary internal heat exchanger Ea disposed immediately thereafter. Here, even when the engine cooling water cannot be used for heating due to its low temperature, the air is heated by flowing the refrigerant which is in a high temperature and high pressure state in a relatively short time to the auxiliary internal heat exchanger Ea, so Demonstrate performance. Moreover, the sub heat exchanger 3
In No. 3, since the heat is not drawn from the air flowing through the air passage 10f to be blown into the vehicle interior, but is drawn from the outside air outside the unit case 10, the immediate warming property is also improved. .

If the refrigerant is heated by the outside air in the sub heat exchanger 33 as described above, the heat held by the outside air can be effectively taken into the refrigerant, so that the refrigerant is returned to the compressor 2 and pressurized again. The refrigerant discharged from the compressor 2 becomes a higher-temperature refrigerant, and when the air is heated again in the auxiliary internal heat exchanger Ea, the air can be converted to a considerably high-temperature air, thereby exhibiting high heating performance. it can.

Since the refrigerant flowing through the sub heat exchanger 33 is heated and evaporates into a gaseous state here, there is no danger of the liquid refrigerant returning to the compressor 2, and there is no possibility that the compressor 2 performs a liquid compression operation. Damage can be prevented.

The air heated in the auxiliary internal heat exchanger Ea flows down in the air passage 10f and reaches the heater core 13. Here, the heater core 13 is a part of the engine 1
Although the engine cooling water whose temperature has risen to some extent due to the start of the engine is circulated, it is not preferable to use the engine cooling water for heating since the temperature of the engine cooling water at this time has not yet sufficiently risen.

Therefore, the hot water cock 12 is closed to prevent the engine cooling water from flowing into the heater core 13 or to prevent the air from passing through the heater core 13 by the air mix door 15. Thereby, the air introduced into the air passage 10f from the intake unit becomes considerably high temperature air heated by the auxiliary internal heat exchanger Ea and is blown into the vehicle interior.

When the vehicle interior warms to some extent by the above operation, the switch for the flow path switching valve 31 is turned off to close the bypass circuit 30, and the refrigerant flowing out of the auxiliary internal heat exchanger Ea is discharged to the second flow control valve 5b. And the main internal heat exchanger Eb. The refrigerant flowing out of the auxiliary internal heat exchanger Ea is:
The second flow control valve 5b passes through the second flow control valve 5b.
Is a temperature-sensitive type, and is adjusted so as to have a predetermined valve opening according to the outlet refrigerant temperature of the main internal heat exchanger Eb. That is, since the temperature of the refrigerant at the outlet of the main internal heat exchanger Eb becomes low, the refrigerant is made to flow at a reduced opening degree to restrict the flow rate. Since the refrigerant is adiabatically expanded by the second flow control valve 5b and becomes a low-temperature and low-pressure refrigerant, the air passing through the main internal heat exchanger Eb is dehumidified and cooled. Here, the refrigerant evaporates and becomes gaseous.

Therefore, the air sent from the intake unit 11 is cooled by the main internal heat exchanger Eb,
Immediately after that, it is heated by the auxiliary internal heat exchanger Ea. That is, the dehumidifying and heating operation is performed. As described above, since the auxiliary internal heat exchanger Ea heats the air dehumidified by the main internal heat exchanger Eb, the windshield does not become cloudy even when heating is performed in a so-called indoor air circulation mode, and the operation can be performed in a clear window. Yes, driving safety is also improved.

When the outside air temperature is high (for example, + 5 ° C. to +
When the engine is under high load operation, or the like, the engine cooling water becomes high enough to be used for heating. Therefore, it is not necessary to heat using a high-temperature refrigerant pressurized by a compressor. Therefore, in the present embodiment, for example, the clutch or the like connecting the engine and the compressor 2 is disengaged, and the operation of the compressor 2 is stopped.
The heating operation is performed only by the heater core 13. In this way, there is no unnecessary load on the engine,
The fuel-efficient heating operation becomes possible.

<< Cooling operation >> When the outside air temperature is, for example, +15
In the case of performing the cooling operation at a temperature of about 30 ° C. to + 30 ° C., the refrigerant directly enters the external heat exchanger 3 via the four-way valve 6 as shown in FIG. In addition, the first flow control valve 5a is throttled, and the second flow control valve 5b is also operated so that its opening is adjusted and throttled.

When the compressor 2 is operated in this state,
The discharged refrigerant is supplied to the external heat exchanger 3 as shown in FIG.
Enters, cools and condenses. The low temperature and high pressure refrigerant is
After being stored in the liquid tank 4 to some extent, the flow rate is restricted by the throttled first flow rate control valve 5a, where the flow rate is adiabatically expanded, turned into a lower-temperature low-pressure refrigerant, and flows into the auxiliary internal heat exchanger Ea. Further, the flow of the refrigerant flowing down is restricted by the throttled second flow control valve 5b, where it is adiabatically expanded, becomes a lower-temperature refrigerant at a lower temperature, and enters the main internal heat exchanger Eb. The refrigerant evaporates in the main internal heat exchanger Eb and becomes gaseous.

Therefore, the air sent from the intake unit 11 is first dehumidified and cooled to some extent by the main internal heat exchanger Eb, and further cooled by the auxiliary internal heat exchanger Ea disposed immediately thereafter. In other words, so-called multi-stage cooling is performed, and high cooling performance is exhibited.

However, if the outside air temperature is about 15 ° C. to 20 ° C., there is a possibility that the occupants will have too much air conditioning.
The opening degree of the air mix door 15 on the front surface of the heater core 13 is adjusted, cold air is branched to the heater core 13 side and the bypass passage 14 side, and they are mixed again to reach a predetermined temperature and then blown into the vehicle interior.

When the outside air temperature is equal to or higher than + 30 ° C., the cooling operation in the second embodiment is basically the same as the cooling operation at + 15 ° C. to + 30 ° C.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the claims. For example, in the embodiment, the bypass circuit B that bypasses the external heat exchanger 3 is provided. However, if the air is heated by the auxiliary internal heat exchanger Ea through which the high-temperature and high-pressure refrigerant flows, and the air can be heated, Such a bypass circuit B is not necessarily required.

[0045]

As described above, according to the present invention, at the time of starting heating, air is heated not only by the heater core through which the engine cooling water flows but also by the auxiliary internal heat exchanger through which the high-temperature and high-pressure refrigerant flows. Heating performance can be dramatically improved.

Further, at the time of starting heating, the external heat is pumped by the sub heat exchanger 33 provided in the bypass circuit without using the main internal heat exchanger, so that higher heating performance can be exhibited.

By adjusting the opening of the first or second flow control valve, the auxiliary internal heat exchanger or the main internal heat exchanger can be used as a condenser or an evaporator with a simple circuit configuration. Thus, it is possible to prevent dehumidifying heating and excessive cooling, to create a so-called dry air conditioner, perform various operations, and further improve cooling performance.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a state during a heating operation of a heat pump type air conditioner for a vehicle according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a state during a cooling operation of the embodiment.

FIG. 3 is a schematic configuration diagram of a conventional automotive air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 2 ... Compressor 3 ... External heat exchanger 5 ... Refrigerant expansion member 5a ... 1st flow control valve 5b ... 2nd flow control valve 10 ... Unit case 10f ... Air path 13 ... Heater core 30 ... Bypass circuit 31 ... Flow path switching valve 32 ... Capillary tube (refrigerant expansion member) 33 ... Sub heat exchanger E ... Internal heat exchanger Ea ... Auxiliary internal heat exchanger Eb ... Main internal heat exchanger R ... Return circuit.

Claims (1)

[Claims] 1. A cooling cycle for returning a refrigerant discharged from a compressor (2) to said compressor (2) via an external heat exchanger (3), a refrigerant expansion member (5) and an internal heat exchanger (E). And wherein the internal heat exchanger (E) is disposed in the air passage (10f) of the unit case (10), wherein the refrigerant expansion member (5) and the internal heat exchanger ( E)
A first flow control valve (5a), an auxiliary internal heat exchanger (Ea),
Second flow control valve (5b) and main internal heat exchanger (Eb)
The auxiliary internal heat exchanger (Ea) and the main internal heat exchanger (Eb) are arranged in the air path (10f) so as to face each other. The auxiliary internal heat exchanger (Ea) and the main internal heat exchanger (Eb) can function as an evaporator or a condenser, respectively, by adjusting the opening of the flow control valve (5a) and the second flow control valve (5b). Further, in the cooling cycle, the refrigerant flowing out of the auxiliary internal heat exchanger (Ea) at the time of heating bypasses the second flow control valve (5b) and the main internal heat exchanger (Eb). A bypass circuit (30) for returning to (2), a refrigerant expansion member (32) and a sub heat exchanger (33) provided in the bypass circuit (30), and the sub heat exchanger (33) Unit case (10)
A heat pump type air conditioner for a vehicle, wherein the sub-heat exchanger (33) heats the refrigerant flowing out of the auxiliary internal heat exchanger (Ea) with outside air. .