JPH0384364A - Air conditioner - Google Patents

Abstract

PURPOSE:To prevent the excessive increase and the excessive decrease of capacity of a compres sor and to enable efficient operation of an air conditioner by providing an expansion valve opening correcting means which corrects the opening of an electronic expansion valve accord ing to an overload or a light load when the overload or the light load is detected by a load state detecting means. CONSTITUTION:An open air temperature detected by an open air temperature sensor 13 and a room temperature detected by a room temperature sensor 7 are inputted to a load state detecting means 31 of a controller 30, where the load state of a compressor 1 is detected according to an input from a memory means 35. A load state detected by the load state detecting means 31 is inputted to an expansion valve opening correcting means 32, where an expansion valve opening decided by an expansion valve opening deciding means 26 is corrected according to an input from a memory means 33. For example, when the compressor is in an overload state, the opening of an expansion valve is increased to a value being 1.3 times, when it is in an ordinary load state, the opening is increased to a value being 1.0 times, and when it is in a light load state, the opening is increased to a value being 0.9 times. The expansion valve opening corrected by the expansion valve opening correcting means 32 is outputted through an output means 28 to an electronic expansion valve 4, and the opening of the electronic expansion valve 4 is set to a corrected value.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an air conditioner.

(Conventional technology) A refrigerant circuit of a conventional air conditioner is shown in FIG.

During cooling operation, refrigerant gas discharged from the inverter-driven compression Ill passes through the four-way switching valve 2 and enters the outdoor heat exchanger 3, as shown by the solid arrow, where it is sent from the outdoor fan 1o driven by the motor 9. It condenses and liquefies by dissipating heat into the outside air. Next, this refrigerant liquid enters the electronic expansion valve 4, where it is throttled to reduce the pressure.
The indoor air enters the indoor heat exchanger 5, where the indoor air blown by the indoor fan 11 driven by the motor 8 is cooled and evaporated. This refrigerant gas then returns to the inverter-driven compressor 1 via the four-way switching valve 2 and the accumulator 6.

During heating operation, the refrigerant flows through the inverter-driven compressor 1, four-way switching valve 2, indoor heat exchanger 5, electronic expansion valve 4, outdoor heat exchanger 3, four-way switching valve 2, and accumulator 6, as shown by the broken arrows. Cycle in this order.

The room temperature etc. detected by the room temperature sensor 7 are input to the controller 20, and commands from the controller 20 are output to the compressor driving inverter 12, the four-way switching valve 2, the electronic expansion valve 4, the motor 8.9, etc. .

FIG. 5 shows a control block diagram of the controller 20.

The room temperature detected by the room temperature sensor 7 is sent to the controller 2.
The temperature is inputted to the comparing means 21 of 0, and is compared with the set temperature set by the temperature setting device 22, thereby calculating the deviation between the two. This deviation is input to frequency determining means 23, where the frequency is determined in accordance with the input from storage means 24. Note that the storage means 24 stores a predetermined frequency corresponding to the deviation. The determined frequency is outputted to the inverter 12 via the output means 25, where the frequency of the current supplied to the compression m1 is changed to the determined frequency. Thus, the air conditioning capacity of the air conditioner has a value that corresponds to the air conditioning load.

The frequency determined by the frequency determining means 23 is input to the expansion valve opening determining means 26, where the expansion valve opening is determined according to the input from the storage means 27. Note that the storage means 27
As shown in FIG. 6, the expansion valve opening degree corresponding to the frequency is determined and stored in advance. The determined expansion valve opening degree is output to the electronic expansion valve 4 via the output means 28, and the opening degree of the electronic expansion valve 4 becomes the determined opening degree.

(Problems to be Solved by the Invention) In the conventional air conditioner described above, the frequency of the inverter 12 and the opening degree of the electronic expansion valve 4 correspond in a nearly one-to-one relationship, as shown in FIG. Therefore, when compressor 1 becomes overloaded, the amount of refrigerant circulating becomes insufficient, and compressor 1
lack of ability. On the other hand, when the compressor 1 is in a light load state, there is a problem that the amount of refrigerant circulated becomes excessive and the capacity on the compressor becomes excessive.

(Means for Solving the Problems) The present invention was invented to solve the above problems, and the gist thereof is to provide an inverter-driven compressor and an electronic expansion valve. In an air conditioner in which the opening degree is controlled in accordance with the frequency of the inverter, there is provided a load state detection means for detecting the load state of the compressor, and a load state detection means for detecting an overload or a light load. The air conditioner is characterized by being provided with expansion valve opening correction means for correcting the opening of the electronic expansion valve accordingly.

(Function) Since the present invention has the above configuration, when overload or light load of the compressor is detected, the opening degree of the electronic expansion valve is corrected accordingly.

Embodiment One embodiment of the invention is shown in FIGS. 1-3.

As shown in FIG. 3, an outside air temperature sensor 13 is provided to detect outside air temperature, and the output of this sensor 13 is manually input to a controller 30. The commands from this controller 30 are sent to the inverter 12, the four-way switching valve 2, the motor 9,
It is output to the motor 8 and electronic expansion valve 4.

The rest of the structure is the same as the conventional one shown in FIG. 5, and corresponding members are given the same reference numerals.

A control block diagram of the controller 30 is shown in FIG. 1, and a flowchart is shown in FIG.

Outside temperature detected by outside temperature sensor 13 and room temperature sensor 7
The detected room temperature is input to the load state detection means 31 of the controller 30, where the load state of the compressor 1 is detected in accordance with the input from the storage means 35. Note that the judgment criteria shown in Table 1 are predetermined and stored in the storage means 35.

Table 1: However, A>B, C>D, E>F, G>H For example, during cooling operation, the outside temperature T0 is above A"C, and the room'/
If Mr T i is 00 or more, it is determined that there is an overload state. If the outside temperature T0 is below B'C and the room temperature T is below 0°C, it is determined that the vehicle is in a light load state. Outside air @ T
o is below A'C, B is above C, and room'/Mc
If T is below 0°C and above D''CC, it is determined that the load is normal.

The load condition detected by the load condition detection means 31 is inputted to the expansion valve opening degree correction means 32, which adjusts the expansion valve opening degree determined by the expansion valve opening degree determination means 26 according to the human power from the storage means 33. to correct. Note that the storage means 33 stores a predetermined correction amount corresponding to the load condition. For example, in an overload condition, the expansion valve opening degree is increased to 1.3 times, and in a normal load condition, the expansion valve opening degree is increased to 1.3 times. , 1.0 times, if the load is light, 0
．． It is said to be 9 times more.

The expansion valve opening degree corrected by the expansion valve opening degree correction means 32 is outputted to the electronic expansion valve 4 via the output means 28.
The opening degree is the corrected opening degree.

Other structures and functions are similar to those of the conventional one shown in FIG. 5, and corresponding members are given the same reference numerals.

Thus, when the compressor 1 is in a normal load state, the opening degree of the electronic expansion valve 4 is determined by the expansion valve opening determining means 26, that is, the opening degree is one-to-one with the frequency of the impark 12 as in the conventional one. However, if the load is overloaded, the opening will be larger than in the normal load condition, increasing the amount of refrigerant circulation, and if the load is light, the opening will be smaller than that in the normal load condition. The amount of refrigerant circulation decreases as the opening degree increases.

(Effects of the Invention) In the present invention, there is provided a load state detection means for detecting the load state of the compressor, and when the load state detection means detects an overload or a light load, the opening of the electronic expansion valve is adjusted accordingly. Since the expansion valve opening correction means for correcting is provided, when an overload or light load of the compressor is detected, the opening of the electronic expansion valve is corrected accordingly.

As a result, the amount of refrigerant circulation can be controlled according to the load condition of the compressor, thereby preventing excessive or insufficient capacity of the compressor and allowing the air conditioner to operate efficiently.

[Brief explanation of drawings]

1 to 3 show one embodiment of the present invention, in which FIG. 1 is a control block diagram, FIG. 2 is a flowchart, and FIG. 3 is a system diagram. Figures 4 to 6 show an example of a conventional air conditioner, where Figure 4 is a system diagram, Figure 5 is a control block diagram, and Figure 6 shows the relationship between inverter frequency and expansion valve opening. It is a line diagram. Inverter-driven compressor-l, electronic expansion valve-4, inverter...12, controller 30, load state detection

Claims (1)

[Claims] In an air conditioner comprising an inverter-driven compressor and an electronic expansion valve, the opening degree of the electronic expansion valve is controlled in accordance with the frequency of the inverter, the load state detection means for detecting the load state of the compressor; An air conditioner comprising expansion valve opening degree correction means for correcting the opening degree of the electronic expansion valve in response to the detection of overload or light load by the load state detection means.