JPH05196284A - Control device for heating overload - Google Patents

Abstract

PURPOSE:To perform an economical construction of a heating overload controller of an air conditioner having reliability in operation with a less number of component parts and less number of manufacturing steps. CONSTITUTION:A heating overload control device is comprised of an outdoor heat exchanger temperature sensing means 7 for sensing the temperature of an outdoor heat exchanger with a thermistor arranged in a high pressure pipe of refrigerant cycle and the like, a surrounding air temperature sensing means 8 such as a thermistor and the like, and a comparing and calculating means 9 for inputting the result of each of these detected temperatures, comparing them with the pre-inputted set temperature and calculating them. In addition, they are provided with an outdoor fan motor operating and stopping signal outputting means 10 for outputting operation signal or stopping signal of the outdoor fan motor 6 in reference to these results of comparison, and an outdoor fan motor operating and stopping means 11. for operating and stopping the outdoor fan motor through a relay and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating overload control device for suppressing overload during heating operation of an air conditioner.

[0002]

2. Description of the Related Art Generally, during heating operation in an air conditioner, there are problems such as mechanical wear caused by an increase in refrigerant pressure in a compressor due to overload and deterioration of components due to an increase in refrigerant temperature. Therefore, heating overload control that suppresses overload during heating operation is necessary to protect the compressor or refrigerant cycle components.

FIG. 5 is a schematic diagram of an electric circuit of a conventional heating overload control device in an air conditioner, 51 is an outdoor fan motor, 52 is a pressure switch, and the high pressure of a refrigerant cycle is increased during heating operation. Pressure detector installed in the pipe
It is turned on / off by a detection output of a preset pressure value (not shown). 53 is a power supply,
The outdoor fan motor 51 and the pressure switch 52 are connected in series, and the outdoor fan motor 51 is operated or stopped by the pressure switch 52 that is turned on / off by the output of the pressure detection unit.

FIG. 6 is a diagram for explaining the operation of FIG. 5, in which FIG. 6 (a) shows the change in the refrigerant pressure, and FIG. 6 (b) shows the operating state of the outdoor fan motor 51 at that time.

A pressure detection unit (not shown) disposed in the high-pressure pipe of the refrigerant cycle and controlling the operation of the pressure switch 52 detects the upper limit set pressure P ₁ set in consideration of the outside air temperature in advance. Then, the operation of the outdoor fan motor 51 is stopped, and the pressure in the high-pressure pipe of the refrigerant cycle is reduced due to the reduction in the capacity of the outdoor heat exchanger due to the stop,
When the reduced pressure reaches a preset lower limit set pressure P ₂ , the pressure detection unit detects the pressure and the outdoor fan motor 51 is activated.

Conventionally, as described above, the overload during the heating operation of the air conditioner is suppressed, and the refrigerant pressure is suppressed within a certain range of pressure to be protected.

[0007]

However, in the above-mentioned conventional configuration, an expensive pressure switch is required, and the pressure detecting portion is arranged in the high pressure pipe of the refrigerant cycle with a lot of vibration, so that the reliability is deteriorated. Or, there is a problem that the number of manufacturing processes increases. Further, there is a problem of frost formation on the outdoor heat exchanger when the outdoor fan motor is stopped, and there is a problem that it is necessary to perform defrost control even when the outdoor fan motor is overloaded.

In view of the above, it is an object of the present invention to economically realize a reliable heating overload control device for an air conditioner with a small number of parts without increasing the number of manufacturing steps.

[0009]

According to the present invention, an outdoor heat exchanger temperature detecting means for detecting the temperature of an outdoor heat exchanger by a thermistor or the like provided in a high-pressure pipe of a refrigerant cycle, and an outside air temperature detecting means for a thermistor or the like. And a comparison calculation means for inputting each temperature detection result of these both temperature detection means and comparing with a preset temperature input in advance, and an outdoor fan motor operation for outputting an operation or stop signal of the outdoor fan motor according to the comparison result. A stop signal output means and an outdoor fan motor operation stopping means for operating and stopping the outdoor fan motor via a relay or the like are provided.

As another means, the outdoor heat exchanger temperature detecting means is constituted by a refrigerant discharge temperature detecting means.

[0011]

According to the present invention, the temperature of the outdoor heat exchanger increased by the increase of the refrigerant pressure is compared with the preset temperature corresponding to the preset outdoor temperature, or the temperature at which the refrigerant discharge pipe temperature is detected is calculated. The outdoor heat exchanger is stopped by the OFF signal output by the comparison result calculated by the preset temperature set above, and the capacity of the outdoor heat exchanger is reduced accordingly. The harmony machine is protected.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of an electric circuit according to an embodiment of the present invention. Reference numeral 1 is a thermistor for detecting a pipe temperature of an outdoor heat exchanger, 2 is a thermistor for detecting an outside air temperature, and each of these thermistors. The pipe temperature and the outside air temperature detected by are input to the microcomputer 3 (hereinafter referred to as a microcomputer). The microcomputer 3 compares and calculates the input pipe temperature of the outdoor heat exchanger and the outside air temperature with a preset temperature that has been input in advance. Reference numeral 4 denotes a relay of operation stopping means, which is turned on / off according to a result of comparison and calculation of the pipe temperature and the outside air temperature by the microcomputer 3, and a power source 5
The power input to the outdoor fan motor 6 from is turned on / off, and the outdoor fan motor 6 is operated or stopped.

FIG. 2 is a flow chart for explaining the operation of FIG. 1, and FIG. 3 is a waveform diagram for explaining the operation.

First, in the flow chart of FIG. 2, the outside air temperature detected by a thermistor or the like at the time of heating overload is compared with the preset input temperature t _{1 of the} protection upper limit (S1). S1 · yes) is compared with the pipe temperature t _a of the lower limit of the outdoor heat exchanger (S2), and outputs the operation signal of the outdoor fan motor 6 to above (S3), over the (S2 · yes) of the outdoor heat exchanger The stop signal is output (S4) and the outdoor fan motor 6 is stopped until the temperature becomes _lower than the pipe temperature t _c . When it becomes lower than the lower limit pipe temperature t _c (S6
・ Yes) Operate the outdoor fan motor 6 (S3) Start S1
Return to.

If the detected outside air temperature is lower than the upper limit set temperature t ₁ (S1 · no), it is compared with the intermediate pipe temperature t _{b of the} outdoor heat exchanger, and until it exceeds (S5 · no) the outdoor fan motor. The operation signal of 6 is output (S3), and when it exceeds (S5 ・ y
es) The outdoor fan motor 6 is stopped until the pipe temperature of the outdoor heat exchanger becomes _lower than t _c (S4). Lower limit pipe temperature t _c
When it becomes less than (S6, yes), the outdoor fan motor 6 is operated (S3), and the process returns to the first S1.

Although the present invention is configured as described above, the outdoor heat exchanger uses the temperature of the refrigerant discharge pipe instead of the pipe temperature, so that the refrigerant pressure is suppressed below the pressure P to be protected as described above. At the same time, if the set temperature is appropriately selected, the temperature of the discharged refrigerant can be suppressed within the temperature range to be protected.

Although the heating load control device for an air conditioner according to the present invention has been described above, the configuration of each of these means is summarized in a block diagram as shown in FIG.

That is, during the heating operation of the present invention, the outdoor heat exchanger temperature detecting means 7 for detecting the temperature of the outdoor heat exchanger by the temperature sensor such as the pipe thermistor, and the outdoor air temperature detecting means for detecting the outdoor air temperature by the thermistor or the like. 8, a comparison calculation means 9 for comparing the detection result with a set temperature, an outdoor fan motor operation stop signal output means 10 for outputting an operation / stop signal of the outdoor fan motor by its output, and an outdoor fan motor by a relay or the like. The outdoor fan motor operation stop means 11 for operating and stopping is provided to control the operation of the outdoor fan motor 6 of the air conditioner. This is the temperature of the outdoor heat exchanger that rises due to the temperature rise of the refrigerant, the result of the comparison calculation with the preset temperature set according to the outside air temperature, the above-mentioned, configured to operate or stop the outdoor fan motor, The outdoor fan motor can be operated within a range in which the temperature of the outdoor heat exchanger does not exceed the set temperature.

By using the temperature of the refrigerant discharge pipe instead of the temperature of the outdoor heat exchanger according to the same idea, it is possible to achieve exactly the same purpose.

[0021]

As described above, the heating overload control device of the present invention can easily suppress the overload of the outdoor heat exchanger during the heating operation, and moreover, detect the temperature of the outdoor heat exchanger. The means and the comparison calculation means can be configured to also serve as the defrost control means, and the outside air temperature detection means can also serve as the low temperature control and the low noise control during the cooling operation, so that the manufacturing man-hours can be reduced with a small number of parts. It is economical to configure.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an electric circuit according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of FIG.

FIG. 3 is a waveform diagram illustrating the operation of FIG.

FIG. 4 is a block diagram showing a configuration of each means of the present invention.

FIG. 5 is a schematic diagram of an electric circuit in a conventional air conditioner.

FIG. 6 is a waveform diagram illustrating the operation of FIG.

[Explanation of symbols]

1 ... Pipe temperature detection thermistor, 2 ... Outside air temperature detection thermistor, 3 ... Microcomputer, 4 ... Relay, 5
... power supply, 6 ... outdoor fan motor, 7 ... outdoor heat exchanger temperature detection means, 8 ... outside air temperature detection means, 9 ... comparison calculation means, 10 ... fan motor operation stop signal output means, 11
… Means for stopping fan motor operation.

Claims (2)

[Claims] 1. In an air conditioner, an outdoor heat exchanger temperature detecting means for detecting the temperature of the outdoor heat exchanger by a thermistor or the like provided in a high-pressure pipe of a refrigerant cycle, and an outside air temperature detecting means such as a thermistor. Comparison calculation means for inputting each temperature detection result of both temperature detection means and comparison calculation with the preset temperature input beforehand, and outdoor fan motor operation / stop signal output that outputs the operation or stop signal of the outdoor fan motor according to the comparison result A heating overload control device comprising: means and an outdoor fan motor operation stopping means for operating and stopping the outdoor fan motor via a relay or the like. 2. The heating overload control device according to claim 1, wherein the outdoor heat exchanger temperature detecting means is constituted by a refrigerant discharge temperature detecting means.