JPS6329169A - Air conditioner - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat pump type air conditioner that controls component devices according to the operating state of the system.

[Conventional technology]

FIG. 1 is a block diagram showing, as an example, a refrigeration cycle of a heat pump type air conditioner disclosed in Japanese Utility Model Application Publication No. 59-23065. 1 is a configuration block diagram showing a refrigeration cycle of a heat pump type air conditioner.

(Configuration) In the figure, 1 is a refrigerant compressor, 2 is a four-way valve, 3 is an electric expansion valve as an expansion mechanism, 4 is an indoor heat exchanger, 5 is an outdoor heat exchanger, and 6 is a compression Machine 1. Control units 6a and 6b that control the four-way valve 2 and the electric expansion valve 3 are thermistors for detecting the operating state of the refrigeration cycle, respectively.

FIG. 2 is a block diagram of an electric circuit that is the basis of the conventional system and the present invention. 7 is a microcomputer, and an input circuit 9. CPtJ I O, memory 11, output circuit 12
Based on the temperature information detected by the signal detection unit 8, the operating conditions of the fan motor, compressor motor 15, and electric expansion valve 16 are determined by a predetermined program (not shown).
The motor 1 of the compression R1 is controlled via the drive unit 13 so that the indoor temperature reaches a preset temperature.
5, the fan motor 14, and the opening degree of the electric expansion valve 3 to prevent the refrigerant from returning to the compressor 1 and maintain the maximum capacity.

Moreover, FIG. 6 is a functional block diagram of this type of air conditioner which is not shown in the cited Japanese Utility Model Publication No. 59-23065. This type of air conditioner has a compressor discharge refrigerant temperature T
F, detector 21 and compressor suction refrigerant temperature T, 1 detector 22
Means 25 for determining whether the opening degree of the electric expansion valve 3 is almost open or almost closed based on the compressor discharge refrigerant temperature T6 and the compressor suction refrigerant temperature T detected through the means 27 for determining a correction value for the opening degree of the electric expansion valve 3;
and a means 29 for controlling the opening degree of the electric expansion jF.

(Operation) Next, the operation of the above conventional example having these configurations will be explained. 71'AI is an operation sequence flowchart in the heating operation mode. When the operation switch (not shown) is depressed, the control unit 6 in FIG. 1 starts operating, and in step 41, the discharge refrigerant temperature Tr of the pressure IFD machine 1 detected by the bowl thermistors 6a and 6b: and ,
The suction refrigerant temperature Ts of the compressor 1 and the outdoor heat exchanger temperature are manually input, and in step 42, the compressor discharge refrigerant temperature T6 and the minimum value T0 of the set temperature range are compared, and step 45 is performed.
As shown in FIG. 43, an opening/closing command for the electric expansion valve I-3 is sent through the output section (IEK+not shown) of the control section 6. That is, in step 42, if the compressor discharge refrigerant temperature T is higher than the minimum value T0 of the set temperature range (
In the case of No), the electric expansion valve 3 is opened in step 45, and if the compressor discharge refrigerant temperature T is lower than the minimum value To of the set temperature range, the electric expansion valve 3 is opened in step 43.
Close the opening.

Next, in step 44, the compressor discharge refrigerant temperature T6 and the maximum value T of the set temperature range are compared, and in step 43.
45, an opening/closing command for the electric expansion valve 3 is issued via the discharge force section (not shown) of the control section 6. That is, in step 44, the compressor discharge refrigerant temperature T,
is higher than the maximum value T1 of the set temperature range, step 4
Step 5 opens the opening of the electric expansion valve fr-3, and if the compressor discharge refrigerant temperature T is lower than the maximum value T of the set temperature range, the opening of the electric expansion valve 3 is closed in step 43.

Next, in step 46, the compressor suction refrigerant temperature Ts and the set temperature T3 are compared, and as in steps 45/47,
Electric expansion valve 3 via an output part (not shown) of control part 6
An open/close command is issued. That is, if the compressor suction refrigerant temperature T3+ is higher than the set temperature T3 in step 46, the opening degree of the electric expansion valve 3 is opened in step 45,
Further, if the compressor suction refrigerant temperature T is lower than the set temperature T3, the opening degree of the electric expansion valve 3 is closed in step 46.

Therefore, in the air conditioner, the opening degree of the electric expansion valve 3,
The structure was designed so that it could maintain optimal conditions depending on the driving situation.

(Four points to be solved by the invention) However, as shown below, in the conventional air conditioner, the opening and closing of the electric expansion valve 3 is controlled only by the discharge refrigerant temperature TP and the suction refrigerant temperature Ts of the compressor. Therefore, if the electric expansion valve F3 does not operate due to a malfunction or the like, for example, if the electric expansion valve 3 is left fully open and does not operate,
The control unit 6 continues to operate the air conditioner even though the electric expansion valve 3 is commanded to close the opening degree. Therefore, the largest amount of refrigerant liquid is compressor 1
The person was exiled to Japan, and not only the electric expansion valve 3 but also the compressor 1 were damaged.
There was a problem in that it could cause a serious situation that would lead to an illegal situation.

This invention was made in order to solve the problems of the conventional example as described above. The object of the present invention is to provide an air conditioner equipped with a control system that does not cause damage to the compressor as described above due to the return of refrigerant to the compressor.

[Means for solving problems]

Therefore, in the air conditioner according to the present invention, the I
The electric expansion valve is fully opened by detecting the time after the start of operation of the device, the compressor refrigerant discharge temperature, and the temperature difference between the compressor refrigerant discharge temperature and the suction refrigerant temperature. In order to prevent damage to the compressor due to return of refrigerant when the compressor is fixed in this state, a compressor stop means is provided to achieve the above object.

[Effect]

With the configuration as shown in F-F, in this invention, if the electric expansion valve is fixed in the fully open state due to a malfunction or the like, the operation of the compressor is stopped, the entire air conditioner is stopped, and the refrigerant liquid is The possibility of compressor MJfl etc. due to return is eliminated.

(Example) The present invention will be explained below based on examples.

(Configuration) The configuration of the refrigeration cycle is exactly the same as that of the conventional air conditioner, and as shown in FIG.
It is composed of an indoor heat exchanger 4, an outdoor heat exchanger 5, a four-way valve 2, and an electric expansion valve 3, and repeated explanation will be omitted.

FIG. 3 shows a functional block diagram of the present invention, and the same (equivalent) components as in the conventional example shown in FIG. 6 are denoted by the same reference numerals. Compressor discharge refrigerant temperature T6 detected by compressor discharge refrigerant temperature detector 21, compressor suction refrigerant temperature Tq detected by compressor suction temperature detection 22, compressor operating frequency detector 23 detected A means 26 for determining an abnormality in the electric expansion fr, 3 (FIG. 1) from the operating frequency 11z and each output value at a time set by the time setting means 24; It is provided with means 28 for stopping. In addition, 2
5, 27, and 29 are the same as in the conventional example shown in FIG.

(Operation) Next, the operation in the above configuration will be explained. FIG. 4 is a control operation sequence flowchart of this embodiment, which is stored in the control unit 6 (FIG. 1) to protect the compressor 1 from refrigerant liquid return due to the fully open state of the electric expansion valve 3. Shows the control program.

First, the compressor 1 is activated by turning on the operation switch (not shown), canceling the defrost operation mode, or depending on the compressor operation conditions.
When any of the above is turned on, the flowchart shown in FIG. 4 starts. The timer starts in step 31,
After a certain period of time t+HiM (for example, 30 minutes), proceed to the next step 32. In steps 32.33.34, the compressor operating frequency command sent from the control unit 6 to the compressor 1 is the maximum value 11zIIIax, and the compressor discharge refrigerant temperature T4. is a preset temperature T2 (for example, 70
℃), and the discharge refrigerant temperature of the compressor 1 T1. , and the suction refrigerant temperature T, , is lower than a preset temperature T3 (for example, 86° C.), the process proceeds to the next step 35, and if even one of these conditions is not satisfied, the present invention Therefore, protection control by fully opening the electric expansion 03 is not performed.

Next, in step 36, the opening degree V of the electric expansion valve 3 is set to fully open V.
0 to a constant value △V (for example, 64 of a stepping motor
Pulse minutes) Close. Furthermore, in step 37, a certain period of time t
After 2 passages (eg 10 minutes) repeat steps 32.33.
34, the compressor operating frequency command sent from the control unit 6 to the compressor 1 is the maximum value tlzmax, and the compressor discharge refrigerant temperature T6 is lower than the preset temperature T2, and When the difference between the discharge refrigerant temperature T2 and the suction refrigerant temperature T8 of the compressor is lower than the preset humidity T3, the control unit 6 determines that the electric expansion pump F3 is malfunctioning, and performs step 39. The operation of compressor 1 is stopped. Furthermore, if even one of the stiffening conditions is not satisfied, the compressor is allowed to continue operating without being stopped by the protective brochure ram.

(Other Embodiments) Next, other embodiments of the present invention will be described. FIG. 5 is a control operation sequence flowchart showing a protection program for stopping the operation of the air conditioner when the electric expansion valve 3 stored in the control unit of the second embodiment is fixed in the fully open state. , the difference from FIG. 4 is that step 39
This is because step 40 is provided immediately before the refrigeration cycle, and a lower limit value P1 that regulates the operable pressure of the compressor discharge pressure P is set on the high pressure side of the refrigeration cycle.

Therefore, especially in the cooling mode, even if there is no abnormality in the electric type 1 expansion valve 3 and it is operating normally, the compressor operating frequency command is the maximum value + 1zmax,
and the compressor discharge refrigerant temperature TE is lower than a preset value T2, and the difference between the compressor discharge refrigerant temperature T and the suction refrigerant temperature Tg is lower than a preset value T3, The control unit 6 does not judge that the electric expansion valve 3 has an abnormal character and stop the operation.

〔Effect of the invention〕

As explained above, in this invention, the control unit is equipped with a program that stops the operation of the air conditioner when the electric expansion valve is abnormally fixed in the fully open state. There is no possibility that the compressor will be damaged due to the return of refrigerant due to an abnormality, and the reliability of the entire system as an air conditioner can be significantly improved.

[Brief explanation of the drawing]

1r: A is a configuration block diagram of a refrigeration cycle of an air conditioner that is the basis of the conventional and one embodiment of the present invention; FIG. 2 is an electric circuit block diagram of the conventional control unit and the control section of FIG. 1; 4 is a functional block diagram of an embodiment of the present invention, FIG. 4 is an operational flowchart of the example in FIG. 3, FIG. 5 is an operational flowchart of another embodiment, and FIG. 6 is a conventional example. The functional block diagram, FIG. 7, is an operational flowchart of the example shown in FIG. l...Compressor 3...Electric expansion valve 6...Control section

Claims (2)

[Claims] (1) In an air conditioner comprising a refrigeration cycle having an electric expansion valve as an expansion mechanism and a control unit that controls the operating frequency of a refrigerant compressor and the opening degree of the electric expansion valve, the electric expansion valve is When the electric expansion valve does not close for a predetermined period of time in the fully open state, the compressor operating frequency, the compressor discharge refrigerant temperature, the temperature difference between the compressor discharge refrigerant temperature and the suction refrigerant temperature, and the period setting means are used to determine whether the electric expansion valve is abnormal. An air conditioner characterized by comprising a control section having means for determining whether or not the air conditioner is present and stopping operation of the air conditioner. (2) The air according to claim 1, wherein a lower limit pressure regulation at which the compressor can operate is set on the high pressure side of the refrigeration cycle when the air conditioner is in a cooling mode. harmonizer.