JPH01225864A - Electric expansion valve control device for air-conditioning machine - Google Patents

Abstract

PURPOSE:To minimize the deviation of the opening degree of a valve due to the hysteresis of the electric expansion valve itself, by detecting the number of times of driving of the electric expansion valve, which is caused by the change of an indoor load, to return the opening degree of the valve to the initial state again when the number of times of driving has arrived at a predetermined value. CONSTITUTION:Upon starting operation, an initializing means 17 sets the opening degree of an electric expansion valve 4 at the initial degree of opening by a detecting signal from a detecting means 14 through a control means 13. Next, a valve opening degree setting means 12 sets the opening degree of the electric expansion valve 4 through the control means 13 in accordance with an indoor temperature, detected by a detecting means 11. Thereafter, a number of times of driving detecting means 15 detects the number of times of driving of the electric expansion valve 4, which is caused by the change of an indoor load, and when a number of times of driving comparing means 16 judges that a predetermined number of times has been achieved, the opening degree of the electric expansion valve 4 is initializing again through the initializing means 17 and the control means 13. Thus, the deviation of the opening degree of the valve, due to hysteresis possessed by the electric expansion valve itself, may be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the control of an electrically operated expansion valve whose opening degree can be adjusted as an expansion mechanism in a refrigeration system of an air-cooled heat pump type air conditioner.

Conventional technology Conventionally, when controlling the capacity of air-cooled heat pump air conditioners, an electrically operated expansion valve with adjustable opening was controlled according to fluctuations in the indoor load.This method will be explained below with reference to the drawings. do.

FIG. 3 is a diagram of the refrigeration system of a general air conditioner.

In Fig. 3, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is an electric expansion valve, and 6 is an outdoor heat exchanger, which are connected in series to form a refrigeration system. are doing. The control system for driving the electric expansion valve 4 includes an electric expansion valve control means, a room temperature detection means/means 7 for adjusting the valve opening depending on the indoor load, and a valve of the expansion valve 4 that is smeared according to the detected temperature. It is provided with a valve opening degree setting means 8 for setting the opening degree, and is also provided with a start-of-operation detecting means for initializing the electric expansion valve 4 at the start of operation. In the refrigeration system shown in FIG. 3, the refrigerant discharged from the compressor 1 is switched by a four-way valve 2 as a switching valve, as shown in the figure by a solid line during cooling operation and a broken line during heating operation, as shown in the figure.

In such an air conditioner, when cooling or heating operation is started, the operation start detection means 8 detects the start of operation, and the electric expansion valve control means 6 first initializes the electric expansion valve 4, that is, completely initializes the electric expansion valve 4. Close it. Thereafter, while the indoor load condition is detected by the indoor temperature detection means 7, the valve opening degree of the electric expansion valve 4 is set by the valve opening degree setting means 8 according to the load condition, and the electric expansion valve control is performed. The means 6 opens and closes the electric expansion valve 4.

Problems to be Solved by the Invention However, in the above configuration, after initialization at the start of operation, the valve opening degree of the electric expansion valve 4 changes frequently in accordance with fluctuations in the indoor load. However, electric expansion valve 4
Since the valve itself has hysteresis when opening and closing the valve, frequent opening and closing of the valve causes 1. If the valve is operated for a long period of time, the necessary valve opening degree will deviate depending on the load condition in the room. As a result, an appropriate flow rate of refrigerant cannot be obtained for the indoor load condition, leading to the supply of too much or too little capacity, resulting in failure to achieve comfortable air conditioning and wasteful power consumption. .

In view of the above-mentioned problems, an object of the present invention is to supply capacity according to the indoor load by correcting the valve opening degree by periodically initializing the deviation in the valve opening degree of the electric expansion valve. The present invention provides an electric expansion valve control device for an air conditioner.

Means for Solving the Problems In order to solve the above problems, the present invention provides an electric expansion valve whose opening degree can be adjusted, an indoor temperature detection means for detecting the indoor temperature,
an expansion/opening degree setting means for setting the valve opening degree of the electric expansion valve according to the indoor load based on a signal from the indoor temperature detection means; a drive number detection means for detecting the number of times the electric expansion valve is driven; a drive number comparison means for comparing the signal of the drive number detection means with a predetermined number of drives; an operation start time detection means for detecting whether the compressor starts or stops; the drive number comparison means and the operation start time detection means; an initializing means for initializing the valve opening of the electric expansion valve to fully close or fully open; and an electric motor for controlling the electric expansion valve opening according to signals from the valve opening setting means and the initializing means. It is equipped with an expansion valve control means.

With the above-described configuration, the present invention detects the number of times the electric expansion valve is driven due to changes in indoor load even after initializing the valve opening of the electric expansion valve at the start of operation, and maintains the predetermined number of times of operation. In this case, the opening degree of the electric expansion valve is initialized again every time the electric expansion valve is driven a certain number of times. It is possible to minimize the deviation.

Example An embodiment of the present invention will be described with reference to the drawings.

In Fig. 1, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is an electric expansion valve, and 5 is an outdoor heat exchanger, which are connected in series to form a refrigeration system. are doing. The control system for driving the electric expansion valve 4 includes an indoor temperature detection means 11 that detects the indoor temperature, and a valve opening degree setting means that sets the valve opening degree of the stain-operated expansion valve 4 based on a signal from the indoor temperature detection means 11. 12 and an electric expansion valve control means 13 for driving and controlling the electric expansion valve 4 according to the signals from the expansion/opening degree setting means 1 and 2, and a means 15 for detecting the number of times the compressor starts/stops and starts operation. The electric expansion valve 4 is initialized by the driving number comparing means 16, which compares the number of driving times with a predetermined driving number according to the signal from the detecting means 16, and by receiving the signals from the driving number comparing means 16 and the operation start detection means '14. An initialization means 17 is provided, and a stain-operated expansion valve control means 13 drives and controls the electric expansion valve 4 based on signals from the initialization means 17 and the valve opening degree setting means 12. Electric expansion valve 4 in such a configuration
The control system is housed in a microcomputer (not shown) or the like.

The operation of the electric expansion valve control system having such a configuration will be explained based on the flowchart shown in FIG.

When operation (cooling or heating operation) is started, it is determined in step 21 whether the compressor is ON or OFF.

However, in order to ensure that the electric expansion valve 4 is initialized immediately after the start of operation, the compressor 1 is not turned on until initialization is performed. If the compressor 1 is OFF, initialization (closing the valve) is performed using the steering knob 22, and if the compressor 1 is ON, step 22 is skipped.

In step 23, the indoor temperature is detected, and in step 24, it is determined whether or not to change the valve opening degree. If there is no need to change the valve opening degree, return to step 23.

When the valve opening degree is required, the valve opening degree is set using the steering knob 25 depending on the conditions, and the valve of the electric expansion valve 4 is driven using the steering knob 26. The step knob 27 counts the number of times the electric expansion valve 4 is driven each time the electric expansion valve 4 is driven, and in step 28 it is determined whether the number of times the electric expansion valve 4 is driven is equal to or greater than a predetermined value (for example, a number of times). , if it is less than a predetermined value, step 2
If the compressor 1 is OFF, initialization (closing the valve) is performed.

In this way, by detecting the number of times the electric expansion valve is driven and initializing the valve opening degree of the electric expansion valve when the number of times the electric expansion valve is driven exceeds a predetermined value, it is possible to operate the electric expansion valve for a long time and increase the opening/closing frequency of the electric expansion valve. Even if the valve opening is high, the valve opening is periodically initialized and a standard is set, so even if there is a deviation in the valve opening due to the hysteresis of the electric expansion valve itself, this can be minimized. This makes it possible to supply the capacity of the air conditioner in accordance with the indoor load condition, and also to prevent unnecessary use of electric power.

Effects of the Invention As is clear from the above explanation, the electric expansion valve control device for an air conditioner of the present invention detects the indoor load using the indoor temperature detection means, and adjusts the valve opening degree setting means accordingly. The valve opening degree of the electric expansion valve is set and the electric expansion valve control means is used to control the valve opening degree of the electric expansion valve. Detection of the number of drives by the drive number detection means and drive number comparison means for determining whether the number of drives is greater than or equal to a predetermined value.
The electric expansion valve is now initialized.

From the above configuration, from the initialization of the electric expansion valve that is performed when cooling or heating operation is started, the electric expansion valve is opened and closed frequently due to frequent fluctuations in the indoor load. The valve opening degree will be initialized periodically depending on the number of times.

Therefore, it becomes possible to minimize the deviation in the valve opening degree due to hysteresis of the electric expansion valve. Being able to minimize deviations in valve opening in this way means that the air conditioner can supply the capacity that matches the indoor load conditions into the room, without compromising indoor comfort and wasting power. There is no need to use it, and it is extremely effective in improving comfort and saving energy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of electric expansion valve control of the present invention, FIG. 2 is a flowchart showing an example of electric expansion valve control, and FIG. 3 is a block diagram showing conventional electric expansion valve control. . 4...Electric expansion valve, 11...Indoor temperature detection means, 12...Valve opening degree setting means, 13...
. . . Electric expansion valve control means, 14 . . . Operation start detection means, 15 . . . Drive number detection means, 1
6...drive count comparison means, 1 completion...initialization means. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
figure

Claims (1)

[Claims] An electric expansion valve whose opening degree can be adjusted, an indoor temperature detection means for detecting the indoor temperature, and a valve which sets the valve opening degree of the electric expansion valve according to the indoor load based on a signal from the indoor temperature detection means. an opening setting means; a driving number detecting means for detecting the number of times the electric expansion valve is driven; a driving number comparing means for comparing the number of driving times with a predetermined number of driving times based on a signal from the driving number detecting means; a detection means for detecting the start of operation;
an initialization means for initializing the valve opening of the electric expansion valve to be fully closed or fully opened by the drive number comparison means and the operation start time detection means; the valve opening setting means; and the initialization means; An electric expansion valve control device for an air conditioner, comprising electric expansion valve control means for controlling the valve opening degree of the electric expansion valve based on a signal.