JPH0948234A - Air conditioner - Google Patents

Abstract

(57) [Summary] [Purpose] Prevents frost from the evaporator without causing a sudden change in the temperature of air blown into the room. [Configuration] Target outlet temperature TAO of air blown into the passenger compartment
Is calculated in step 130, and it is determined in step 170 whether or not this TAO is equal to or higher than the set temperature C set as a temperature slightly higher than the temperature at which the indoor heat exchanger (evaporator) starts to frost. Then, if the determination result is YES, the air temperature Te after passing through the indoor heat exchanger is controlled to be TAO, and conversely, if NO, the Te is controlled to be the set temperature C. As a result, the compressor is always in the operating state regardless of TAO and does not fall below the set temperature C, so that the temperature of the air blown into the passenger compartment does not suddenly change and the frost of the indoor heat exchanger can be prevented. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with an evaporator for a refrigeration cycle in an air conditioning duct, blows air cooled by this evaporator into a room, and condensate water is frozen (frost) on the surface of the evaporator. The present invention relates to an air conditioner that can prevent

[0002]

2. Description of the Related Art As a conventional technique of the above air conditioner, there is a vehicle air conditioner disclosed in, for example, Japanese Patent Laid-Open No. 2-231220. This is because the evaporator inside the air conditioning duct is equipped with a temperature sensor, and the rotation speed of the compressor is controlled based on the value detected by this temperature sensor to control the temperature of the air blown into the vehicle compartment through the air conditioning duct. are doing.

Further, when the detected value of the temperature sensor becomes lower than a preset temperature as a temperature at which the evaporator starts to frost, the operation of the compressor is stopped to prevent the frost of the evaporator. I am trying.

[0004]

However, in the above-mentioned prior art, when the detected value of the temperature sensor becomes lower than the set temperature, the operation of the compressor is stopped, so that the outside air temperature at that time is high, Alternatively, if there is a large amount of solar radiation, there is a problem that the temperature of the blown air rises sharply when the operation of the compressor is stopped, causing an occupant in the passenger compartment to feel uncomfortable.

In view of the above problems, the present invention provides an air conditioner for controlling the temperature of air blown into a room by controlling the number of revolutions of a compressor to control the temperature of an evaporator. The purpose of the present invention is to prevent the frost of the evaporator without causing a rapid change in

[0006]

In order to achieve the above-mentioned object, the present invention provides an air-conditioning duct (2) for guiding the air generated by the blower means (3) into the room, and a compressor ( 10), condensers (62, 11), and pressure reducing means (1
2) together with the refrigeration cycle (4),
Evaporator (14) provided in the air conditioning duct (2)
And a rotation speed adjusting means (19) for adjusting the rotation speed of the compressor (10), and controlling the rotation speed of the compressor (10) adjusted by the rotation speed adjusting means (19). In the air conditioner configured to control the temperature of the air blown into the room, the evaporator temperature detecting means (45) for detecting the temperature of the evaporator (14), and the target blowout temperature of the air blown into the room ( Target air temperature calculation means (step 130) for calculating TAO), the target air temperature (TAO), and a temperature slightly higher than the temperature at which condensed water begins to freeze on the surface of the evaporator (14). The determination means (step 170) for determining the magnitude relationship with the set temperature (C) thus set, and the determination means (step 17)
0) determines that the target outlet temperature (TAO) is higher than the set temperature (C), the evaporator temperature (Te) detected by the evaporator temperature detecting means (45) is equal to the target outlet temperature (Te). First rotation speed control means (steps 180 to 200) for controlling the rotation speed adjustment means (19) so as to reach the temperature (TAO), and the determination means (step 17).
0) determines that the target outlet temperature (TAO) is lower than the set temperature (C), the evaporator temperature (Te) detected by the evaporator temperature detection means (45) is the set temperature. Second rotation speed control means (step 21) for controlling the rotation speed adjusting means (19) so as to become (C).
0-230).

According to a second aspect of the present invention, in the air conditioner according to the first aspect, a target air flow rate determining means (V0) for determining a target air flow rate (V0) into the room based on the target outlet temperature (TAO) ( Step 150) and blower control means (step 160) for controlling the blower means (3) so that the blown air amount generated by the blower means (3) becomes the target blown air amount (V 0). Is characterized by.

[0008] According to a third aspect of the present invention, in the air conditioner according to the first or second aspect, the evaporator temperature detecting means (45) detects the air temperature immediately after passing through the evaporator (14). Air temperature detection means (4
It is characterized in that it is composed of 5). According to a fourth aspect of the invention, in the air conditioner according to any one of the first to third aspects, the compressor (10) is an electric motor (3
2) is rotationally driven by the rotation speed adjusting means (1
9) is characterized by being composed of an inverter (19) for varying the frequency of the electric power supplied to the electric motor (32).

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

[0010]

According to the inventions of claims 1 to 4,
When the target blowout temperature is higher than the set temperature, the rotation speed of the compressor is controlled so that the temperature detected by the evaporator temperature detecting means becomes the target blowout temperature. Therefore, of course, the condensed water does not freeze on the surface of the evaporator,
The temperature of the air blown into the room is controlled to a temperature according to the target blowout temperature. Further, when the target outlet temperature is lower than the set temperature, the rotation speed of the compressor is controlled so that the temperature detected by the evaporator temperature detecting means becomes the set temperature. Therefore, of course, even at this time, the evaporator does not frost.

As described above, according to the present invention, the compressor is always in operation regardless of the target outlet temperature, and the evaporator temperature does not become lower than the set temperature, so that the frost of the evaporator can be prevented and It is possible to eliminate the problem that the temperature of blown air fluctuates abruptly as in the prior art.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an air conditioner used in a vehicle (specifically, an electric vehicle) will be described with reference to FIGS. First, the overall configuration of this embodiment will be described with reference to FIG. The air conditioner 1 includes an air conditioning duct 2 that guides air to be blown into the vehicle interior, and a blower 3 that generates an air flow in the air conditioning duct 2 and pressure-feeds the air into the vehicle interior.
, Accumulator type refrigeration cycle 4 and hot water circuit 5
And an air conditioner control device 6.

On the air upstream side of the air-conditioning duct 2, there are provided an inside air intake port 6 for taking in the air inside the vehicle, an outside air intake port 8 for taking in the outside air, and an inside / outside air switching door 9 for selectively opening / closing these. ing. The blower means 3 is arranged at the downstream side of the inside / outside air switching door 9. Further, in the air-conditioning duct 2 at a site on the downstream side of the blower means 3,
An indoor heat exchanger 14 forming a part of the refrigeration cycle 4 is provided. Further, a heater core 61, which is a part of the hot water circuit 5, is arranged at a downstream side portion of the indoor heat exchanger 14 in the air conditioning duct 2. Further, the heater core 61 is provided with an air mix door 64 for adjusting the amount of air flowing in the heater core 61. The air mix door 64 fully closes the heater core 61 during a cooling operation described later, and opens the heater core 61 according to a target outlet temperature TAO described later during a heating operation described later.

At the air downstream end of the air conditioning duct 2,
A defroster outlet 2a that blows conditioned air toward the window glass of the vehicle, a face outlet 2b that blows conditioned air toward the upper half of the occupant, and a foot outlet 2c that blows conditioned air toward the occupant's feet are formed. Has been done. These outlets 2a to 2c are selectively opened and closed by an outlet switching door (not shown).

By the way, the refrigeration cycle 4 includes the compressor 1
0, the outdoor heat exchanger 11, the cooling decompression means 12, the heating decompression means 13, the indoor heat exchanger 14, the accumulator 1
6 and the refrigerant-hot water heat exchanger 62 are well-known ones connected by a refrigerant pipe 31. Of these, the compressor 10 sucks, compresses, and discharges a refrigerant, and an electric motor 32 that rotationally drives the compressor 10 (see FIG. 2).
Is built-in. The electric motor 32 is driven by receiving electric power from the vehicle running battery 33 (see FIG. 2), and the rotation speed is determined according to the frequency variably controlled by the inverter 19. Therefore, the compressor 1
The refrigerant discharge capacity of 0 changes according to the rotation speed of the electric motor 32.

The outdoor heat exchanger 11 is a heat exchanger which is disposed outside the air conditioning duct 2 (outside the vehicle compartment) and receives air from the outdoor fan 20 to exchange heat between the outside air and the refrigerant. The outdoor heat exchanger 11 functions as a condenser during a cooling operation described later, and functions as an evaporator during a heating operation described later. The cooling decompression means 12 decompresses and expands the high-temperature and high-pressure refrigerant from the outdoor heat exchanger 11 during the cooling operation, and is specifically composed of a capillary tube.

The heating decompression means 13 decompresses and expands the high-temperature high-pressure refrigerant from the refrigerant-hot water heat exchanger 62 during heating operation, and is specifically composed of a capillary tube. The indoor heat exchanger 14 is a heat exchanger that is disposed inside the air conditioning duct 2 and exchanges heat between the air blown from the blower unit 3 and the refrigerant. This indoor heat exchanger 14
Functions as an evaporator during cooling operation, and no refrigerant flows during heating operation.

The accumulator 16 temporarily stores the excess refrigerant in the refrigeration cycle 4 and sends out only the gas refrigerant so that the compressor 10 does not suck the liquid refrigerant.
The refrigerant-hot water heat exchanger 62 is a heat exchanger that is arranged outside the air conditioning duct 2 (outside the vehicle compartment) and that exchanges heat between the high-temperature high-pressure refrigerant from the compressor 10 and the hot water in the hot water circuit 5. The refrigerant-hot water heat exchanger 62 functions as a condenser during both cooling operation and heating operation.

Further, in the refrigeration cycle 4, the bypass passage 25 for guiding the refrigerant from the outdoor heat exchanger 11 to the accumulator 16 by bypassing the cooling decompression means 12 and the refrigerant from the refrigerant-hot water heat exchanger 62 are provided. , Heating decompression means 13
Bypass passage 2 that bypasses the air and leads to the outdoor heat exchanger 11
6 are provided, and solenoid valves 27 and 28 are provided in the middle of each bypass passage.

The hot water circuit 5 includes the heater core 61,
In addition to the refrigerant-hot water heat exchanger 62, combustion heaters 66 are connected by hot water pipes 63, respectively. Of these, the refrigerant-hot water heat exchanger 62 is used in the refrigeration cycle 4
Is a heat exchanger that heats the hot water by exchanging heat of condensation with the hot water flowing in the hot water pipe 63.

The combustion heater 66 is a combustion tank 67.
The hot water is heated by burning the fuel inside. The amount of hot water heated by the combustion heater 66 and the amount of hot water heated by the refrigerant-hot water heat exchanger 62 are adjusted by hot water valves 68 and 69. Next, the control device 6 will be described.

The control device 6 incorporates a well-known microcomputer having an interface (not shown), CPU, ROM, RAM, etc., and, as shown in FIG. 2, signals from each setting device of the air conditioner operation panel 41, A signal from an inside air temperature sensor 42 that detects the vehicle interior temperature, a signal from an outside air temperature sensor 43 that detects the outside air temperature, a signal from a solar radiation sensor 44 that detects the amount of solar radiation radiated into the vehicle interior,
A signal from a sensor 45 (hereinafter, referred to as a post-evaporator sensor) that detects the air temperature in the air conditioning duct 2 immediately after passing through the indoor heat exchanger 14, and the air conditioning duct 2 immediately before passing through the indoor heat exchanger 14. Sensor 46 for detecting the air temperature of
(Hereinafter, referred to as a vaporizer sensor) is input.

When these signals are input, the control device 6 carries out a predetermined control process described later, and based on the result, the inverter 19, the blowing means 3, the solenoid valve 27,
28, hot water valves 68, 69, and other actuators. Next, the flow of the refrigerant during the cooling operation and the heating operation will be described. (During cooling operation) At this time, the solenoid valve 27 is opened and the solenoid valve 28 is closed. As a result, the high-temperature high-pressure refrigerant discharged from the compressor 10 is the refrigerant-hot water heat exchanger 62 → the electromagnetic valve 27 → the outdoor heat exchanger 11 → the cooling decompression means 12 → the indoor heat exchanger 14.
→ The accumulator 16 → the compressor 10 flow in this order. Thereby, the indoor heat exchanger 14 functions as an evaporator, and the air in the air conditioning duct 2 is cooled by the indoor heat exchanger 14.

(At the time of heating operation) At this time, the solenoid valve 27 is closed and the solenoid valve 28 is opened. As a result, the high-temperature high-pressure refrigerant discharged from the compressor 10 flows in the order of the refrigerant-hot water heat exchanger 62 → heating decompression means 13 → outdoor heat exchanger 11 → solenoid valve 28 → accumulator 16 → compressor 10. At this time,
Hot water heated by the heat of condensation of the refrigerant-hot water heat exchanger 62 flows in the heater core 61, and the air in the air conditioning duct 2 is heated by the heater core 61.

Next, the control processing in the microcomputer of the air conditioner control device 6 will be described with reference to the flowchart of FIG. First, when the automatic control process of the air conditioner is started in step 100, step 110
Perform initialization processing at. Then, at step 120, the set temperature Tset in the vehicle compartment set by the temperature setting device of the air conditioner operation panel 41 and the values of the sensors 42 to 46 (vehicle interior temperature Tr, outside air temperature Tam, solar radiation Ts, evaporation). The temperature after vaporization Te and the temperature before vaporization Tin) are read.

Then, in the next step 130, by substituting each value read in the above step 120 into the following formula 1 stored in the ROM, the target outlet temperature (hereinafter referred to as TAO) of the air blown into the passenger compartment is obtained. calculate.

[0027]

## EQU1 ## TAO = Kset × Tset−Kr × Tr−Kam ×
Tam-Ks * Ts + C Here, Kset, Kr, Kam, and Ks are gains, respectively, and C is a correction constant. Then step 140
At the target outlet temperature TA calculated in step 130
Whether or not the cooling operation is performed is determined by determining whether or not the relationship between O and the evaporator pre-temperature Tin detected in step 120 above satisfies the following formula 2 stored in the ROM.

[0028]

## EQU2 ## TAO-Tin <α where α is a predetermined constant and is stored in the ROM 53 in advance. While NO is determined in this step 140, the process of this step 140 is repeated without proceeding to the previous step. If YES is determined in the next step 150, the target air flow rate V0 is determined by searching the target air flow rate V0 corresponding to the target outlet temperature TAO from the map of FIG. 4 stored in advance in the ROM. .
Then, in the next step 160, the air blowing means 3 is controlled so that the actual air blowing amount into the vehicle compartment becomes the target air blowing amount.

Then, in the next step 170, it is determined whether or not the target outlet temperature TAO calculated in step 130 is equal to or higher than a preset temperature C, and if YES is determined, the processes of steps 180 to 200 are performed. If it is determined to be NO, steps 210 to 230 are performed. Here, this set temperature C is set as a temperature (for example, 2 ° C.) slightly higher than the temperature at which the indoor heat exchanger 14 starts to frost.

First, when YES is determined in the step 170, in the following steps 180 to 200, the inverter 19 is operated so that the temperature Te of the air immediately after passing through the indoor heat exchanger 14 becomes the target outlet temperature TAO. Is controlled to control the rotation speed of the compressor 10. Specifically, first step 1
At 80, the post-evaporator temperature Te is the target outlet temperature TAO.
By determining whether or not the above, the indoor heat exchanger 14
Determine whether to lower or raise the temperature of.

If YES is determined in this step, the temperature of the indoor heat exchanger 14 should be lowered, and if NO is determined, the temperature should be increased.
At 0 and 200, the inverter 19 is controlled so that Te = TAO based on the rate of change of TAO-Te and Te, and the rotation speed of the compressor 10 is maintained or increased or decreased. Then, the process returns to step 120.

On the other hand, if NO in step 170, the indoor heat exchanger 14 will be frosted if the same processing as in steps 180 to 200 is performed.
In this case, in steps 210 to 230, the inverter 19 is controlled to control the rotation speed of the compressor 10 so that the temperature Te of the air immediately after passing through the indoor heat exchanger 14 becomes the set temperature C.

Specifically, first, at step 210, it is judged whether the temperature Te of the evaporator is equal to or higher than the preset temperature C, so that the temperature of the indoor heat exchanger 14 should be lowered or increased. To judge. If YES is determined here, the temperature of the indoor heat exchanger 14 should be lowered, and N
If it is determined to be O, it means that the value should be increased. Therefore, in steps 220 and 230, the inverter 19 is controlled so that Te = TAO based on the rate of change of TAO−Te and Te, and the compression is performed. The rotation speed of the machine 10 is maintained or increased or decreased. Then, the process returns to step 120.

The above steps constitute means for realizing the respective functions. As described above, in the present embodiment, first, it is determined whether or not the target outlet temperature TAO is equal to or higher than the set temperature C, and when it is equal to or higher than the set temperature C, the air temperature immediately after passing through the indoor heat exchanger 14 is the target. Outlet temperature T
Since the temperature is controlled so as to be AO, the temperature of the air blown into the vehicle interior also becomes the target air outlet temperature TAO, and the air having a comfortable temperature can be blown to the passenger in the vehicle interior.

When the target outlet air temperature TAO is lower than the preset temperature, the compressor 10 is kept operating and the temperature of the indoor heat exchanger 14 is controlled to reach the preset temperature C. Frost generation in the heat exchanger 14 can be prevented. Further, at this time, since the compressor 10 is still operating as described above, there is no problem that the blown-air temperature fluctuates abruptly as in the prior art.

(Modification) In the above embodiment, the evaporator temperature detecting means according to the invention of claim 1 is used as the indoor heat exchanger 14.
Post-evaporator sensor 4 for detecting the air temperature immediately after passing through
However, it may be configured by means for detecting the temperature of the indoor heat exchanger 14 itself (for example, the temperature of the fins),
It may be configured by means for detecting the temperature of the refrigerant immediately after it exits the indoor heat exchanger 14.

[Brief description of 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 above embodiment.

FIG. 3 is a control flowchart of the above embodiment.

FIG. 4 is a map showing a relationship between a target outlet temperature TAO and a target blown air amount V0.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air-conditioning device, 2 ... Air-conditioning duct, 3 ... Blower means, 4 ... Refrigeration cycle, 6 ... Control device, 10 ... Compressor, 11 ... Outdoor heat exchanger (condenser), 12 ... Cooling decompression means (Decompression means) ), 14 ... Indoor heat exchanger (evaporator), 19 ... Inverter (rotation speed adjusting means), 45 ... Evaporator post-sensor (evaporator temperature detecting means), 62 ... Refrigerant-hot water heat exchanger (condenser).

Claims (4)

[Claims] 1. An air-conditioning duct that guides air generated by a blower into a room, a refrigeration cycle that includes a compressor, a condenser, and a decompressor, and an evaporator provided in the air-conditioning duct; A rotation speed adjusting means for adjusting the rotation speed of the machine is provided, and the temperature of the air blown into the room is controlled by controlling the rotation speed of the compressor adjusted by the rotation speed adjusting means. In an air conditioner, an evaporator temperature detecting means for detecting the temperature of the evaporator, a target outlet temperature calculating means for calculating a target outlet temperature of air blown into the room, the target outlet temperature, and condensation on the surface of the evaporator. Judgment means for judging the magnitude relationship with a preset temperature set as a temperature slightly higher than the temperature at which water begins to freeze, and the target blowout temperature is judged by this judgment means. When it is determined that the temperature is higher than the set temperature, first rotation speed control means for controlling the rotation speed adjustment means so that the evaporator temperature detected by the evaporator temperature detection means becomes the target blowout temperature. When the determination unit determines that the target outlet temperature is lower than the set temperature, the rotation speed adjustment unit is set so that the evaporator temperature detected by the evaporator temperature detection unit becomes the set temperature. An air conditioner comprising: a second rotation speed control unit for controlling the air conditioner. 2. A target air flow rate determining means for determining a target air flow rate into the room based on the target air outlet temperature, and the air blow means so that the air flow rate generated by the air blow means becomes the target air flow rate. An air conditioner according to claim 1, further comprising a blower control means for controlling the air conditioner. 3. The evaporator temperature detecting means comprises an after-evaporator air temperature detecting means for detecting an air temperature immediately after passing through the evaporator. Air conditioner. 4. The compressor is rotatably driven by an electric motor, and the rotation speed adjusting means is composed of an inverter that varies the frequency of the power supplied to the electric motor. The air conditioner according to any one of the above.