JP3334446B2 - 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 gas injection cycle, and is particularly suitable as a heat pump system for air conditioning of an electric vehicle for a cold region.

[0002]

2. Description of the Related Art As an apparatus having a gas injection cycle, there is one disclosed in Japanese Patent Application Laid-Open No. 1-114668. This prior art refrigeration cycle is shown in FIG.
As shown in FIG. 2, the compressor 101, the condenser 102, the first electric expansion valve 103, the gas-liquid separator 104, the second electric expansion valve 105, and the evaporator 106 are each provided with a refrigerant pipe 107.
And the gas refrigerant separated by the gas-liquid separator 104 is connected to the gas injection passage 1.
It is configured so as to be injected into the compressor 101 via the control unit 08.

[0003] The control unit 109 controls the first electric expansion valve 103 so that the degree of supercooling of the condenser 102 becomes smaller than a predetermined value. Thereby, the compressor 10
Maintaining the optimal amount of gas injection into 1
As a result, the heating capacity of the condenser 102 can be sufficiently obtained.

[0004]

However, in the case of the prior art, the first electric expansion valve 103 is controlled so that the degree of supercooling of the condenser 102 is always smaller than the predetermined value. Although the heating capacity of the vessel 102 can be sufficiently obtained, the efficiency of the refrigeration cycle may be deteriorated. On the other hand, if the predetermined value is set with priority given to the efficiency of the refrigeration cycle, the required heating capacity may not be obtained, and the heating capacity may be insufficient.

In view of the above problems, the present invention provides a vehicle air conditioner having a gas injection cycle, which is capable of exhibiting a large heating capacity when necessary while improving the efficiency of a refrigeration cycle. The purpose is to provide.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, claims 1 to 1 are provided.
In the invention described in Item 6, as the refrigeration cycle (21), a compressor (22), a condenser (12), a first depressurizing means (26) whose electric throttle amount is adjusted electrically, a gas-liquid separator (25), Second
A so-called gas injection cycle including a pressure reducing means (27), an evaporator (24), and a gas injection passage (22d) is used. Further, the condenser (12) is provided in the air passage (2), and the control device (40) is provided. ), The number of revolutions of the compressor (22) is controlled so that the heating capacity in the condenser (12) becomes a predetermined capacity, and the degree of supercooling of the liquid refrigerant in the condenser (12) becomes the predetermined degree of supercooling. In the vehicle air conditioner in which the throttle amount of the first pressure reducing means (26) is controlled so as to satisfy the condition, the heating capacity in the condenser (12) reaches a predetermined capacity by the heating capacity determination means (Step 230). It is determined whether or not the aperture is not reached, and when it is determined that the aperture has not been reached, the aperture control of the first pressure reducing means (26) is controlled by the aperture control means for insufficient capacity (step 240) to open. Toshii .

According to this, when the heating capacity reaches the predetermined capacity, the rotation speed of the compressor (22) is controlled so that the heating capacity in the condenser (12) becomes the predetermined capacity, and the condenser (22) is controlled. The throttle amount of the first pressure reducing means (26) is controlled so that the degree of supercooling of the liquid refrigerant in the 12) becomes a predetermined degree of supercooling. Therefore, if the predetermined degree of supercooling is set to, for example, a degree of supercooling that maximizes the efficiency of the refrigeration cycle (21), the efficiency of the refrigeration cycle (21) can always be maximized.

On the other hand, when the heating capacity has not reached the predetermined capacity, the throttle of the first pressure reducing means (26) is opened, so that the amount of gas injected into the compressor (22) through the gas injection passage (22d) is increased. Increase. Therefore, the compressor (22) performs the compression work by adding the refrigerant amount to be gas-injected to the refrigerant circulation amount sucked from the suction port (22b). As a result, the work of compression increases, and the amount of heat released from the refrigerant in the condenser (12) increases, so that the heating capacity increases.

As described above, according to the present invention, when the heating capacity reaches the predetermined capacity, the efficiency of the refrigeration cycle (21) can be controlled with priority, and then, for example, the rapid heating of the vehicle interior When the heating capacity does not reach the above-mentioned predetermined capacity as in the initial stage of performing the above, the heating capacity can be improved, so that the improvement of the efficiency of the refrigeration cycle (21) and the securing of the heating capacity can both be achieved.

[0010] In particular, in the invention according to claim 4, the compressor load determining means (step 2) determines whether the load of the compressor (22) detected by the compressor load detecting means (48) is equal to or more than a predetermined load.
50), and when it is determined that the load is equal to or more than the predetermined load, the compressor throttle amount control means (step 26).
0), the first pressure reducing means (26) is controlled to close the aperture.

According to this, the throttle of the first pressure reducing means (26) is opened by the control of the above-mentioned insufficient capacity throttle amount control means (step 240), and as a result, the compressor (2)
When the load of 2) becomes equal to or more than the predetermined load, the first
Since the throttle of the pressure reducing means (26) is closed and the load increase of the compressor (22) is suppressed, it is possible to prevent the compressor (22) from being overloaded.

According to the present invention, the compressor temperature determining means (step 2) determines whether the temperature of the compressor (22) detected by the compressor temperature detecting means (46) is equal to or higher than a predetermined temperature.
70), when it is determined that the temperature is equal to or higher than the predetermined temperature, the compressor high-temperature throttle amount control means (step 280)
It is characterized in that the first pressure reducing means (26) is controlled so as to open the aperture.

According to this, when the temperature of the compressor (22) becomes equal to or higher than the predetermined temperature, the first pressure reducing means (2)
By opening the throttle in 6), the gas injection amount increases, and the temperature rise of the compressor (22) is suppressed, so that the compressor (22) can be prevented from reaching a predetermined temperature or higher.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment in which the present invention is applied to an air conditioner for an electric vehicle will be described below with reference to FIGS. First, the overall configuration of the present embodiment is shown in FIG.
This will be described with reference to FIG. The air conditioning unit 1 is installed in the cabin of an electric vehicle, and the air conditioning duct 2 constitutes an air passage for guiding conditioned air into the cabin. At one end of the air-conditioning duct 2, suction ports 3, 4, for sucking inside and outside air,
5 are provided. The inside air intake port 4 and the outside air intake port 5 are selectively opened and closed by an inside / outside air switching door 6, and the inside / outside air switching door 6 is driven by a servo motor (not shown).

In the air-conditioning duct 2, the above-mentioned suction port 3 is provided.
A blower 7 for generating an air flow in the air-conditioning duct 2 is installed adjacent to. The blower 7 includes a fan motor 7a and centrifugal fans 7b, 7b driven by the fan motor 7a. On the other hand, at the other end of the air conditioning duct 2, a foot outlet 8 for blowing conditioned air toward the feet of the passenger in the passenger compartment, a face outlet 9 for blowing conditioned air toward the upper body of the passenger in the passenger compartment, and a vehicle front A defroster outlet 10 for blowing conditioned air toward the inner surface of the glass is formed.

A cooling indoor heat exchanger 11 is provided in the air conditioning duct 2 downstream of the blower 7 in the air. The indoor heat exchanger 11 for cooling is a heat exchanger that constitutes a part of a refrigeration cycle 21 described later. In a cooling operation mode and a dehumidification operation mode described below, the air-conditioning duct 11 It functions as an evaporator for dehumidifying and cooling the air inside 2. In a heating operation mode described later, the cooling indoor heat exchanger 1 is used.
No refrigerant flows in 1.

A heating indoor heat exchanger 12 is provided in the air conditioning duct 2 on the downstream side of the air from the cooling indoor heat exchanger 11. This heating indoor heat exchanger 12
Is a heat exchanger that constitutes a part of a refrigeration cycle 21 described later. In a heating operation mode and a dehumidification operation mode described later, a condenser that heats air in the air conditioning duct 2 by radiating the refrigerant flowing inside. Functions as a vessel. Note that, in a cooling operation mode described later, the refrigerant does not flow in the heating indoor heat exchanger 12.

The air flow path in the air conditioning duct 2 is divided by a partition wall 13 into a first air flow path 14 on the foot outlet 8 side.
And a second air passage 15 on the side of the face outlet 9 and the defroster outlet 10. As described above, the air flow path in the air conditioning duct 2 is divided into the first air flow path 14 and the second air flow path 15 because the first air flow path 1
By sucking high-temperature inside air from the inside air inlet 3 into the inside 4 and blowing out warm air to the feet, the heating load is reduced, and at the same time, low-humidity outside air is sucked into the second air passage 15 from the outside air inlet 5. This is to prevent the fogging of the windshield reliably.

The door 16 opens and closes the second air passage 15, and the door 17 comprises the first and second air passages 14, 15.
It opens and closes a partition part between the doors 18 to 20.
Is a door that opens and closes the air flow path of each of the outlets 8, 9, and 10. The doors 16 to 20 are driven by servo motors (not shown) connected to the respective doors. By the way, the refrigeration cycle 21 includes the cooling indoor heat exchanger 1.
This is a heat pump refrigeration cycle for cooling and heating the interior of the vehicle cabin with the indoor heat exchanger 1 and the indoor heat exchanger 12, and includes the following equipment in addition to the indoor heat exchangers 11 and 12.

That is, a compressor 22 for sucking, compressing and discharging refrigerant, an electromagnetic four-way valve 23 for switching the flow of refrigerant,
An outdoor heat exchanger 24, a gas-liquid separator 25 for separating the refrigerant into gas and liquid and storing the liquid refrigerant, and an electric expansion valve for reducing the high-pressure side refrigerant of the refrigeration cycle 21 to an intermediate pressure (for example, about 4 to 15 kg / cm ² ). 26, a temperature-operated expansion valve 27 for reducing the pressure of the liquid refrigerant from the gas-liquid separator 25 to a low pressure, an electromagnetic valve 28a,
28 b and check valves 29 a to 29 e are further provided in the refrigeration cycle 21.

The compressor 22 is an electric compressor, and draws, compresses, and discharges refrigerant when driven by an electric motor (not shown). The electric motor is disposed integrally with the compressor 22 in a sealed case, and the rotation speed is continuously varied by being controlled by the inverter 30. The inverter 30 is connected to the vehicle battery 3
1 and is energized and controlled by the control device 40 (FIG. 2).

The compressor 22 has a discharge port 22a for discharging the compressed refrigerant, a suction port 22b for sucking the refrigerant on the low pressure side of the cycle, and an intermediate-pressure gas refrigerant separated by the gas-liquid separator 25. A gas injection port 22c is provided. The gas injection port 22c communicates with a gas refrigerant outlet 25a at the upper part of the gas-liquid separator 25 via a gas injection passage 22d having a check valve 29e.

A temperature-sensitive cylinder 27a of a temperature-operated expansion valve 27 is provided in a refrigerant suction passage 22e connected to the suction port 22b, and the degree of opening (throttle amount) of the expansion valve 27 is set in the suction passage 22e. Is adjusted so that the degree of superheat of the refrigerant of the second embodiment becomes a predetermined value. The outdoor heat exchanger 24 is installed outside the vehicle compartment, and the electric outdoor fan 24a is
(FIG. 2), the outdoor fan 2
It exchanges heat with the outside air blown from 4a.

The electric expansion valve 26 is controlled to be energized by a control device 40 (FIG. 2), so that the opening degree (throttle amount) of the valve is adjusted. As shown in FIG. 2, the controller 40 includes an outside air temperature sensor 41 for detecting the outside air temperature, a suction temperature sensor 42 for detecting the air temperature on the suction side of the cooling indoor heat exchanger 11, and a cooling indoor heat A post-evaporator temperature sensor 43 for detecting the air temperature immediately after passing through the exchanger 11, an indoor heat exchanger outlet temperature sensor 44 for detecting the refrigerant temperature immediately after leaving the heating indoor heat exchanger 12,
Each detected value from the outdoor heat exchanger outlet temperature sensor 45 for detecting the refrigerant temperature immediately after leaving the outdoor heat exchanger 24 is input.

The control device 40 includes a compressor 22
Refrigerant temperature sensor 4 for detecting the temperature of refrigerant discharged
6. A control panel provided on the front side of the vehicle interior while receiving respective detection values from a high-pressure sensor 47 for detecting a refrigerant pressure at the inlet of the electric expansion valve 26 and a line current sensor 48 for detecting a line current of the inverter 30. 50 levers,
A signal from the switch is input.

As shown in FIG. 3, the control panel 50 includes the following members 5 manually operated by an occupant.
1 to 55 are provided. Here, reference numeral 51 denotes a temperature setting lever for setting a target value of the temperature of the air blown into the vehicle interior;
2 is an air volume switching lever for switching the amount of air blown by the blower 7, 53 is an air conditioner switch for interrupting the operation of the compressor 22, 54 is a blowing mode switching lever for switching the setting of the blowing mode, and 55 is an inside / outside air switching mode. Is an inside / outside air switching lever that switches between.

The temperature setting lever 51 is a lever for setting a target value of the temperature of the air blown into the vehicle cabin. The control device 40 controls a cooling operation mode to be described later in accordance with the setting position of the lever 51. Sometimes, a target value of the degree of air cooling in the indoor heat exchanger 11 for cooling (specifically, the air temperature immediately after passing through the heat exchanger 11) is determined as shown in FIG. In the heating mode and the heating operation mode, the target value of the degree of air heating in the indoor heat exchanger 12 for heating (specifically, the refrigerant pressure discharged from the compressor 22) is determined as shown in FIGS.

The temperature setting lever 51 also functions as a lever for determining the operation mode of the refrigeration cycle 21. As shown in FIG.
The operation mode of the refrigeration cycle 21 is switched according to the set position of 1. That is, the control device 40 controls the refrigeration cycle 2 with the movement of the lever 51 from the left end to the right end in FIG.
The four-way valve 23 and the solenoid valve 28 so that the first operation mode is a cooling operation mode, a dehumidification operation mode, and a heating operation mode.
a and 28b are controlled.

A well-known microcomputer including a CPU, a ROM, a RAM, and the like (not shown) is provided inside the control device 40.
Each signal from the control panel 50 is input to the microcomputer via an input circuit (not shown) in the control device 40. Then, the microcomputer executes predetermined processing described later, and based on the result, the fan motor 7a, the electromagnetic four-way valve 23, the electric outdoor fans 24a and 24a, the electric expansion valve 26, the electromagnetic valve 28
a, 28b and the inverter 30. In addition,
The control device 40 is supplied with power from the battery 31 when a key switch (not shown) of the vehicle is turned on.

When the air conditioner switch 53 is turned on, the signal is input to the control device 40 and the compressor 2 is turned on.
2 is activated. Then, the temperature control lever 51
When the cooling operation mode is set by the above, the refrigerant flows along the path indicated by the arrow C in FIG. That is, the high-temperature and high-pressure refrigerant discharged from the compressor 22 flows into the outdoor heat exchanger 24 through the four-way valve 23 and the check valve 29b, where the outdoor fan 2
The gas refrigerant condenses by exchanging heat with the outside air blown by 4a. Next, the refrigerant flowing out of the outdoor heat exchanger 24 passes through the check valve 29d because the electromagnetic valve 28a is closed,
The pressure is reduced by the electric expansion valve 26 to be in a gas-liquid two-phase state at an intermediate pressure.

The intermediate-pressure gas-liquid two-phase refrigerant is supplied to the gas-liquid separator 2.
5, where the refrigerant is separated into a saturated gas refrigerant and a saturated liquid refrigerant. The gas refrigerant flows from the gas refrigerant outlet 25a at the top of the gas-liquid separator 25 to the gas injection passage 22d,
Through the check valve 29e, the gas injection port 2
2c, an intermediate-pressure gas refrigerant is injected from the port 22c into a part of the compressor 22 during the compression process.

On the other hand, the liquid refrigerant in the gas-liquid separator 25 is supplied to a liquid refrigerant outlet 25b which is open near the bottom of the gas-liquid separator 25.
After flowing out, the pressure is reduced by the temperature-operated expansion valve 27, and after passing through the solenoid valve 28b, it flows into the indoor heat exchanger 11 for cooling. The refrigerant in the heat exchanger 11 is supplied to the blower 7
Absorbs heat from the blast air and evaporates. The cold air absorbed and cooled by the heat exchanger 11 is usually supplied to the face outlet 9.
Is blown out into the vehicle interior, whereby the vehicle interior is cooled.

The gas refrigerant evaporated in the cooling indoor heat exchanger 11 is drawn into the suction port 22b of the compressor 22 from the refrigerant suction passage 22e. At this time, the temperature of the compressor suction refrigerant is sensed by the temperature-sensitive cylinder 27a installed in the refrigerant suction passage 22e, and transmitted to the expansion valve 27.
Adjusts the flow rate of the refrigerant flowing into the heat exchange 11 so that the refrigerant drawn into the compressor has a predetermined degree of superheat.

Next, when the dehumidifying operation mode is set by the temperature control lever 51, the refrigerant flows into an arrow D in FIG.
It flows along the route shown in. That is, the gas refrigerant discharged from the compressor 22 flows into the heating indoor heat exchanger 12 through the four-way valve 23, where the gas refrigerant exchanges heat with the air blown by the blower 7 to condense the gas refrigerant. Then, the refrigerant flowing out of the heat exchanger 12 passes through the check valve 29c and is decompressed by the electric expansion valve 26 to be in a gas-liquid two-phase state at an intermediate pressure.

The intermediate-pressure gas-liquid two-phase refrigerant is supplied to the gas-liquid separator 2.
The gas refrigerant flows into the gas refrigerant 5, and is separated from the gas refrigerant outlet 25a at the upper portion of the gas-liquid separator 25, and is sucked into the gas injection port 22c through the gas injection passage 22d and the check valve 29e. On the other hand, gas-liquid separator 2
The liquid refrigerant in the liquid refrigerant 5 flows out from the liquid refrigerant outlet 25b, is decompressed by the temperature-operated expansion valve 27, and is then opened.
8b, it flows into the indoor heat exchanger 11 for cooling. Then, the refrigerant in the heat exchanger 11 absorbs heat from the air blown by the blower 7 and evaporates. At this time, since the electromagnetic valve 28a is closed, the refrigerant that has exited the heat exchanger 11 does not flow toward the outdoor heat exchanger 24, but is drawn into the compressor 22.

As described above, in the dehumidifying operation mode, the cooling indoor heat exchanger 1 installed in the indoor air conditioning unit 1 is used.
1 and the indoor heating heat exchanger 12, the blown air from the blower 7 is first cooled and dehumidified by the cooling indoor heat exchanger 11, and then by the heating indoor heat exchanger 12. Reheated. Here, the heat radiation amount of the refrigerant in the indoor heat exchanger 12 for heating is obtained by adding the work amount in the compressor 22 to the heat absorption amount in the indoor heat exchanger 11 for cooling.
The temperature of the air blown into the vehicle interior becomes higher than the temperature of the air blown from the inlets 3, 4, and 5. Therefore, while performing dehumidification,
Heating can be performed.

Next, when the heating operation mode is set by the temperature control lever 51, the refrigerant flows into the arrow H in FIG.
It flows along the route shown in. That is, the gas refrigerant discharged from the compressor 22 flows into the heating indoor heat exchanger 12 through the four-way valve 23, where the gas refrigerant exchanges heat with the air blown by the blower 7 to condense the gas refrigerant. The warm air heated by the heat release of the gas refrigerant is mainly blown out from the foot outlet 8 into the vehicle interior, thereby heating the vehicle interior.

Then, the refrigerant that has exited the heating indoor heat exchanger 12 passes through the check valve 29c and is decompressed by the electric expansion valve 26 to be in a gas-liquid two-phase state at an intermediate pressure. The intermediate-pressure gas-liquid two-phase refrigerant flows into the gas-liquid separator 25, and the separated gas refrigerant is supplied to the gas refrigerant outlet 25a at the upper part of the gas-liquid separator 25.
Is sucked into the gas injection port 22c through the gas injection passage 22d and the check valve 29e.

On the other hand, the liquid refrigerant in the gas-liquid separator 25 flows out of the liquid refrigerant outlet 25b, is decompressed by the temperature-operated expansion valve 27, passes through the check valve 29a, and then passes through the outdoor heat exchanger 24.
Flows into. Then, the refrigerant in the outdoor heat exchanger 24 absorbs heat from the blown air (outside air) of the outdoor fan 24a and evaporates. The gas refrigerant evaporated in the outdoor heat exchanger 24 passes through the solenoid valve 28a and passes through the refrigerant suction passage 22e to the compressor 2
It is sucked into the second suction port 22b.

Next, control processing of the electric expansion valve 26 and the inverter 30 by the microcomputer of the control device 40 will be described with reference to the flowchart of FIG. When the power is supplied to the control device 40 by turning on the key switch, the routine of FIG. 8 is started. Then, first in step 100, each of the sensors 41 to 4
8 and the signals from the control panel 50 are read. Then, in the next step 110, the operation mode of the refrigeration cycle 21 is determined according to the set position of the temperature setting lever 51 as shown in FIG.

Then, in the next step 120, it is determined which of the operation modes determined in step 110 is the operation mode. When it is determined that the operation mode is the cooling operation mode, the processing of steps 130 to 170 is performed,
If it is determined that the mode is the heating operation mode, step 18
The processes of 0 to 280 are performed, and when it is determined that the operation mode is the dehumidification operation mode, the processes of steps 290 to 330 are performed.

First, the case where it is determined in step 120 that the operation mode is the cooling operation mode will be described. Step 1
In 30, the target blowing temperature TEO corresponding to the set position of the temperature setting lever 51 is determined by searching the map shown in FIG. 4 stored in the ROM. Then, in the next step 140, the inverter 30 is controlled so that the temperature detected by the post-evaporator temperature sensor 43 (the air temperature immediately after passing through the cooling indoor heat exchanger 11) becomes the TEO.

Then, in the next step 150, the degree of supercooling (SC) of the condensed liquid refrigerant in the outdoor heat exchanger 24 is calculated as follows:
It is calculated based on the following formula 1.

[0044]

SC = T (Ph) -Tos where Tos is a detection value of the outdoor heat exchanger outlet temperature sensor 45. T (Ph) is a refrigerant condensing temperature calculated from a value detected by the high-pressure sensor 47. That is, since the detection value of the high-pressure sensor 47 corresponds to the refrigerant condensing pressure, in the present embodiment, a map (not shown) showing the correlation between the refrigerant condensing pressure and the refrigerant condensing temperature is stored in the ROM, The condensation temperature corresponding to the detected value is calculated by searching this map.

In the next step 160, the target supercooling degree (SCO) corresponding to the outside air temperature detected by the outside air temperature sensor 41 is calculated by searching from the map of FIG. 9 stored in the ROM. By calculating the target supercooling degree SCO from the map of FIG.
4, the cooling COP of the refrigeration cycle 21 (= radiation capacity Q / power W of the compressor 22) can be maximized while optimizing the radiation capacity Q in 4.

That is, generally, in summer when the outside air temperature is high, as the outside air temperature increases, the compressor 22 is operated to cool the interior of the vehicle, thereby ensuring the cooling capacity. Accordingly, at this time, the high-pressure pressure increases, and the refrigerant temperature of the outdoor heat exchanger 24 also increases. As a result, the temperature difference between the refrigerant temperature and the outside air temperature increases. That is, the outdoor heat exchanger 2
4, the heat dissipation capacity Q is increased.

Therefore, the target supercooling degree SCO is calculated as a large value. As a result, even if the power W of the compressor 22 increases, the capacity Q further increases and the cooling COP increases.
Therefore, when the outside air temperature is high, the target supercooling degree SCO is calculated as a large value. Then, in the next step 170, the opening of the electric expansion valve 26 is controlled so that the supercooling degree SC calculated in step 150 becomes the target supercooling degree SCO calculated in step 160. Specifically, first, the deviation (ΔSC) between the SC and the SCO is calculated, and then the increase / decrease opening ΔEVC of the electric expansion valve 26 corresponding to the deviation ΔSC is calculated from a map (not shown) stored in the ROM. I do. Then, the current opening degree of the electric expansion valve 26 is increased / decreased by the increase / decrease opening degree ΔEVC.

Next, the case where it is determined in step 120 that the operation mode is the dehumidification operation mode will be described. In step 290, the target high pressure PCO corresponding to the set position of the temperature setting lever 51 is determined by searching the map shown in FIG. 5 stored in the ROM. And
In the next step 300, the inverter 30 is controlled so that the high pressure detected by the high pressure sensor 47 becomes the PCO.

In the next step 310, the degree of supercooling SC of the condensed liquid refrigerant in the indoor heat exchanger 12 for heating is determined.
Is calculated based on the following equation (2).

[0050]

SC = T (Ph) -Tcs where Tcs is a detection value of the indoor heat exchanger outlet temperature sensor 44. Then, in the next step 320, the target supercooling degree SCO corresponding to the post-evaporator temperature detected by the post-evaporator temperature sensor 43 is calculated by searching the map of FIG. 10 stored in the ROM. By calculating the target supercooling degree SCO from the map of FIG. 10, while optimizing the heat radiation capacity Q in the indoor heating heat exchanger 12,
The dehumidification COP of the refrigeration cycle 21 (= the heat radiation capacity Q / the power W of the compressor 22) can be maximized.

That is, the post-evaporator temperature detected by the post-evaporator temperature sensor 43 corresponds to the temperature of the air passing through the indoor heat exchanger 12 for heating. Accordingly, the fact that the temperature after the evaporator is low means that the temperature difference between the temperature of the refrigerant in the indoor heat exchanger 12 for heating and the temperature of the air passing through the heat exchanger 12 is large. That is, the heat radiation capability Q is large.

Accordingly, the target supercooling degree SCO is calculated as a large value. As a result, even if the power W of the compressor 22 increases, the capacity Q further increases and the dehumidification COP
When the temperature after the evaporator is low, the target supercooling degree SCO is calculated as a large value. Then, in the next step 330, the supercooling degree SC calculated in step 310 is changed to the target supercooling degree SC calculated in step 320.
The opening of the electric expansion valve 26 is controlled so as to be O.
The specific control method of this step 330 is step 17
Since it is the same as 0, its description is omitted.

Next, the case where it is determined in the above step 120 that the heating operation mode is set will be described. In step 180, the target high pressure PCO corresponding to the set position of the temperature setting lever 51 is determined by searching the map shown in FIG. 6 stored in the ROM. And
In the next step 190, the inverter 30 is controlled so that the high pressure detected by the high pressure sensor 47 becomes the PCO.

In the next step 200, the degree of supercooling SC of the condensed liquid refrigerant in the indoor heating heat exchanger 12 is determined.
Is calculated based on Equation 2 above. Then, in the next step 210, the target supercooling degree SCO corresponding to the suction temperature detected by the suction temperature sensor 42 is calculated by searching from the map of FIG. 11 stored in the ROM. By calculating the target degree of supercooling SCO from the map of FIG. 11, the heating COP of the refrigeration cycle 21 is optimized while optimizing the heat radiation capacity Q in the indoor heating heat exchanger 12.
(= Radiation capacity Q / power W of compressor 22) can be maximized.

That is, in the heating operation mode, since the refrigerant does not flow into the cooling indoor heat exchanger 11, the suction temperature detected by the suction temperature sensor 42 (the cooling indoor heat exchanger 11
Of the air on the suction side) corresponds to the temperature of the air passing through the indoor heat exchanger 12 for heating. Therefore, the fact that the suction temperature is low means that the temperature difference between the refrigerant temperature in the indoor heating heat exchanger 12 and the temperature of the air passing through the heat exchanger 12 is large. That is, the heat radiation capability Q is large.

Accordingly, the target supercooling degree SCO is calculated as a large value. As a result, even if the power W of the compressor 22 increases, the capacity Q further increases and the heating COP increases.
When the temperature after the evaporator is low, the target supercooling degree SCO is calculated as a large value. Then, in the next step 220, the supercooling degree SC calculated in step 200 is changed to the target supercooling degree SC calculated in step 210.
The opening of the electric expansion valve 26 is controlled so as to be O.
The specific control method of this step 220 is step 17
Since it is the same as 0, its description is omitted.

By the control in steps 180 to 220, the heating capacity is basically controlled by the compressor speed.
The opening of the electric expansion valve 26 is controlled so that the efficiency (COP) of the refrigeration cycle 21 is maximized. However, for example, when the compressor rotation speed is the maximum rotation and the high pressure is not enough to reach the target high pressure PCO such as in the early stage of the rapid heating of the vehicle interior, the efficiency of the refrigeration cycle 21 is slightly reduced. Even if you drop it, you must give priority to improving the heating capacity.

Therefore, in the present embodiment, the following step 2
At 30, the high pressure detected by the high pressure sensor 47 is equal to the target high pressure P while the compressor speed is the highest.
It is determined whether CO has not been reached. Here, YES
If it is determined that the heating capacity is insufficient, step 2
At 40, the electric expansion valve 26 is opened by a predetermined amount. Note that the compressor speed can be detected based on the inverter frequency input to the control device 40.

According to this, for example, when the electric expansion valve 26 is opened by a predetermined amount by the processing of step 240 while the refrigeration cycle 21 is stable in the state shown by the solid line in FIG. 12 is stabilized in the state shown by the one-dot chain line in FIG. Therefore, the compressor 22
To increase the amount of gas injection into the compressor 22
The compression work is performed by adding the amount of refrigerant injected by gas to the amount of refrigerant circulated through the suction port 22b. As a result, although the work amount of the compressor 22 increases and the efficiency of the refrigeration cycle 21 decreases, the amount of refrigerant radiated by the indoor heating heat exchanger 12 increases.
Heating capacity is improved. Thereby, the shortage of the heating capacity is eliminated.

When the electric expansion valve 26 is opened by the processing in step 240, the amount of gas injection increases, and the work (load) of the compressor 22 increases as described above. The load of 30 increases. Therefore, in the next step 250, it is determined whether the line current of the inverter 30 detected by the line current sensor 48 is equal to or more than a predetermined current.
Is determined to be in an overload state. If the determination is YES, in the next step 260, the electric expansion valve 26 is closed by a predetermined amount. As a result, the gas injection amount to the compressor 22 is reduced, so that the inverter 30 can be prevented from being overloaded.

In the next step 270, it is determined whether or not the compressor 22 is heated above the allowable temperature by checking whether or not the temperature of the discharged refrigerant detected by the discharged refrigerant temperature sensor 46 is higher than a predetermined temperature. I do. If the determination is YES, in step 280, the electric expansion valve 26 is opened by a predetermined amount. As a result, the gas injection amount increases, and the discharge temperature decreases.

As described above, in this embodiment, when the heating capacity is sufficient in the heating operation mode, the opening of the electric expansion valve 26 is controlled so that the efficiency of the refrigeration cycle 21 is maximized. When the heating capacity is insufficient as in the early stage of rapid heating, the opening degree of the electric expansion valve 26 is increased to increase the gas injection amount and improve the heating capacity.
It is possible to achieve both improved efficiency of heating and securing of heating capacity.

(Other Embodiments) In the above embodiment, the insufficient heating capacity is determined based on the high pressure.
The determination may be made based on the air temperature immediately after passing through the heating indoor heat exchanger 12. In short, the determination may be made based on a physical quantity related to the heating capacity of the indoor heat exchanger 12 for heating.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

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

FIG. 3 is a front view of the control panel 50 of the embodiment.

4 is a map showing a relationship between a set position of a temperature setting lever 51 in FIG. 3 and a target outlet temperature in a cooling operation mode.

FIG. 5 is a map showing a relationship between a target high pressure and a set position of the temperature setting lever 51 in a dehumidifying operation mode.

FIG. 6 is a map showing a relationship between a set position of the temperature setting lever 51 and a target high pressure in a heating operation mode.

FIG. 7 is a diagram showing a relationship between a refrigeration cycle operation mode and an entire operation range of the temperature setting lever 51.

FIG. 8 is a control flowchart by the microcomputer of the embodiment.

FIG. 9 shows the outside air temperature and the target supercooling degree SCO in the embodiment.
It is a map showing the relationship with.

FIG. 10 is a map showing a relationship between a post-evaporator temperature and a target degree of supercooling SCO in the embodiment.

FIG. 11 shows a suction temperature and a target supercooling degree SC in the embodiment.
6 is a map showing a relationship with O.

FIG. 12 is a Mollier diagram of the refrigeration cycle 21 of the embodiment.

FIG. 13 is an overall configuration diagram of a conventional apparatus having gas injection.

[Explanation of symbols]

2 ... air conditioning duct (air passage), 7 ... blower, 11 ... cooling indoor heat exchanger, 12 ... heating indoor heat exchanger (condenser), 21 ... refrigeration cycle, 22 ... compressor, 22a ... discharge port, 22b: suction port, 22c: gas injection port, 22d: gas injection passage, 23: four-way valve, 24: outdoor heat exchanger, 25: gas-liquid separator, 26: electric expansion valve (first pressure reducing means), 27: temperature-operated expansion valve (second pressure reducing means), 40: control device, 4
6 ... discharge refrigerant temperature sensor (compressor temperature detection means), 48
... Line current sensor (compressor load detecting means).

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Sadahisa Onimaru 14 Iwatani, Shimowakakucho, Nishio-shi, Aichi Prefecture Inside the Japan Automobile Parts Research Institute (72) Yukatsu Ozaki 14th Iwatani, Shimowasukamachi, Nishio-shi, Aichi Co., Ltd. Examiner in Japan Auto Parts Research Institute, Jun Sano (56) References JP-A-60-111851 (JP, A) JP-A-56-59168 (JP, A) JP-A-59-112165 (JP, A) JP-A-6-11205 (JP, A) JP-A-59-229140 (JP, A) JP-A-6-347129 (JP, A) JP-A-7-139824 (JP, A) JP-A-7-151413 (JP) , A) Japanese Utility Model Showa 57-77863 (JP, U) Japanese Utility Model Showa 50-63272 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60H 1/22 B60H 1/32 624 F25B 13/00 311

Claims (6)

(57) [Claims] 1. A blower (7) for generating an air flow, an air passage (2) for guiding air generated by the blower (7) into a vehicle interior, and a low-pressure refrigerant of a refrigeration cycle (21). Port (22b), a gas injection port (22c) for introducing an intermediate-pressure gas refrigerant of the refrigeration cycle (21), and a discharge port (22a) for discharging the high-pressure refrigerant compressed by itself. A compressor (22) provided in the air passage (2) and condensing high-pressure refrigerant from the discharge port (22a) of the compressor (22); and a condenser (12). A first pressure reducing means (26) configured to reduce the pressure of the high-pressure refrigerant from (12) to the intermediate pressure and to electrically adjust the throttle amount, and an intermediate pressure from the first pressure reducing means (26). cold A gas-liquid separator (25) for separating the liquid refrigerant at an intermediate pressure from the gas-liquid separator (25) to a low pressure; a second pressure reducing means (27) for reducing the pressure of the intermediate-pressure liquid refrigerant to a low pressure; An evaporator (24) for evaporating the low-pressure refrigerant from (27), and an intermediate-pressure gas refrigerant separated by the gas-liquid separator (25) to a gas injection port (22c) of the compressor (22). Passage for gas injection (22
d) compressor speed control means (steps 180 and 190) for controlling the speed of the compressor (22) so that the heating capacity of the condenser (12) becomes a predetermined capacity; and the condenser ( 12) A control device (40) including throttle amount control means (steps 200 to 220) for controlling the throttle amount of the first pressure reducing means (26) such that the degree of subcooling of the liquid refrigerant in the liquid refrigerant becomes a predetermined degree of supercooling. ), The control device (40) includes a heating capacity determination unit (step 230) that determines whether the heating capacity of the condenser (12) has reached the predetermined capacity. When the heating capacity determining means (step 230) determines that the heating capacity of the condenser (12) has not reached the predetermined capacity, the first pressure reducing means (2).
6) An air conditioner for a vehicle, comprising: an insufficient throttle control unit (Step 240) for controlling the first pressure reducing unit (26) so as to open the throttle of (6). 2. The heating capacity determining means (step 23)
0) is configured to determine whether or not the heating capacity of the condenser (12) has reached the predetermined capacity while the compressor (22) is at the maximum rotation speed. The vehicle air conditioner according to claim 1. 3. The vehicle air conditioner according to claim 1, wherein the predetermined degree of subcooling is such that the coefficient of performance of the refrigeration cycle is maximized. 4. A compressor (40) comprising a compressor load detecting means (48) for detecting a load on the compressor (22), wherein the control device (40) comprises a compressor (40) detected by the compressor load detecting means (48). 2
(2) a compressor load determining means (step 250) for determining whether the load is equal to or more than a predetermined load; and the compressor load determining means (step 250) determines whether the load of the compressor (22) is equal to or more than the predetermined load. When it is determined that there is, a compressor high load throttle amount control means (step 260) for controlling the first pressure reducer (26) so as to close the throttle of the first pressure reducer (26). The vehicle air conditioner according to any one of claims 1 to 3, wherein: 5. Compressor temperature detecting means (46) for detecting a temperature of the compressor (22), wherein the control device (40) comprises: a compressor (40) detected by the compressor temperature detecting means (46). 2
(2) a compressor temperature determining means (step 270) for determining whether or not the temperature of the compressor (22) is equal to or higher than the predetermined temperature; When it is determined that there is, a compressor high-temperature throttle amount control means (step 280) for controlling the first pressure reducer (26) so as to open the throttle of the first pressure reducer (26). The vehicle air conditioner according to any one of claims 1 to 4, wherein 6. An air conditioner for a vehicle according to claim 1, wherein an electric compressor driven by an electric motor is used as said compressor. .