JPH024177A - Electronic expansion valve control device - Google Patents

Abstract

PURPOSE:To set the optimum initial valve opening degree in each operation modes and permit a delivery temperature to be approached to a target value within a short period of time by setting the initial opening degree of an electronic expansion valve in accordance with the output of an operation mode detecting means. CONSTITUTION:A preset operation mode is detected by an operation mode detecting means 14 simultaneously with the throw-in of a power source and the initial opening degree of a valve corresponding to respective operation modes is outputted from an initial valve opening degree setting means 15 to change the valve opening degree of an electronic expansion valve 3 in accordance with the outputted opening degree of the valve. Next, the set value of a delivery temperature is set in an objective temperature setting means 8 while the set value is compared with the output of a temperature detecting means 7 by a temperature comparing means 9. When the delivery temperature is higher than the objective temperature, the opening degree of the valve is increased. When the delivery temperature is lower than the target value, the opening degree of the valve is decreased. The opening degree of the valve is maintained for a given period of time as it is and, thereafter, the delivery temperature is compared with the target temperature again.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for an electronic expansion valve used in a refrigeration cycle.

BACKGROUND OF THE INVENTION In recent years, electronic expansion valves, which can be controlled in a variety of ways by microcomputers, have been developed as devices for dividing the flow rate of refrigerant in a refrigeration cycle.

Hereinafter, an example of a control device for an electronic expansion valve in the conventional refrigeration cycle described above will be described with reference to the drawings.

FIG. 4 shows the configuration of the refrigeration cycle.

In Fig. 4, 1 is a compressor, 2 is a first heat exchanger, 3 is an electronic expansion valve, 4 is a second heat exchanger, 5 is a discharge temperature sensor that detects the discharge temperature, and 6b is a discharge temperature sensor. This is a control device that controls the electronic expansion valve 3 using the signal No. 5.

FIG. 5 is a block diagram of the control device 6b.

The control device 6b includes an initial valve opening setting means 12 for setting an initial valve opening, a temperature detecting means 7 including a discharge temperature sensor 5, etc., and a target for setting a target value of the discharge temperature according to the operating status of the refrigeration cycle. Temperature comparison means 9 for comparing the outputs of the temperature setting means 8 and the temperature detection means 7 with the output of the target temperature setting means 8
, a valve opening degree calculation means 10 that calculates the valve opening degree based on the output of the temperature comparison means 9, and a valve opening degree output means 11 that outputs the valve opening degree according to the output of the valve opening degree calculation means 10.

The operation of the refrigeration cycle and control circuit configured as above will be explained.

FIG. 6 is a flow chart showing the operation of the electronic expansion valve 3.

In operation, first, the control device 6b is energized, and the valve opening degree of the electronic expansion valve is set by the initial valve opening degree setting means 12. The discharge temperature Td detected by the discharge temperature detection means 7 consisting of the discharge temperature sensor 5 and the temperature T set by the target temperature setting means 8
The temperature difference ΔTd between the temperature and the temperature difference ΔTd between the temperature and the temperature difference ΔTd between the temperature and the Then, the valve opening calculation means 10 determines the valve opening according to this temperature difference ΔTd, and the valve opening output means 11 changes the opening of the electronic expansion valve 3 to adjust the discharge temperature Td to the target value Ts. I'm trying to get closer. Note that the valve opening degree set to - degree is maintained for at least a certain period of time.

Problems to be Solved by the Invention In the conventional control device 6b of the electronic expansion valve 3, when electricity is first turned on, the initial valve opening is set at a certain constant valve opening regardless of whether cooling operation or heating operation is performed. be done. However, when comparing the valve opening degree of the electronic expansion valve 3 that increases the efficiency of the refrigeration cycle during cooling operation and heating operation, it is found that the valve opening degree during cooling operation tends to be larger than the valve opening degree during heating operation.

Therefore, if the initial valve opening is determined preferentially during cooling when the valve opening is large, the discharge temperature Td can be brought close to the set temperature Ts in a short time as per the target during cooling operation, but during heating operation the discharge temperature There is a problem in that it takes a long time to bring Td close to the set temperature Ts, and sufficient heating performance cannot be obtained within a short time after the start of operation.

Furthermore, if the valve opening degree during heating operation is determined preferentially, the amount of refrigerant circulating in the refrigeration cycle becomes too small at the start of cooling operation, and the discharge temperature rises rapidly, causing reliability of the refrigeration cycle parts including compressor 1. There is a problem in that it has a negative impact on sexuality.

Means for Solving the Problems In order to solve the above problems, the electronic expansion valve control device of the present invention includes initial valve opening setting means similar to conventional control devices;
A temperature detection means, a target temperature setting means, a temperature comparison means, a valve opening calculation means, a valve opening output means, an operation mode detection means, and an initial valve opening according to the output of the operation mode detection means are newly set. An initial valve opening setting means is provided.

Effect: With the above-described configuration, when the control device is first energized, the operation mode detecting means detects the set operation mode at the same time as the energization, and sets the initial valve opening degree for each operation mode. do.

Thereafter, the same discharge temperature control as in the conventional example is performed.

Embodiment A control device for an electronic expansion valve according to an embodiment of the present invention will be described below.

FIG. 1 is a refrigeration cycle diagram of one embodiment, in which a compressor 1,
Four-way valve 13, first heat exchanger 2, electronic expansion valve 3, second
The heat exchanger 4 is connected in a ring shape. The valve opening degree of the electronic expansion valve 3 is controlled by a control device 6a that uses the output temperature of the discharge temperature sensor 5 as an input signal.

FIG. 2 is a block diagram of the control device 6a.

Driving mode detection means 14 for detecting the current driving mode;
Initial valve opening setting means 15 for setting the initial valve opening according to the output of the operation mode detection means 14, temperature detection means 7 for measuring the discharge temperature, target temperature setting means 8 for setting the target value of the discharge temperature, temperature Temperature comparison means 9 that compares the output of the detection means 7 and the output of the target temperature setting means 8, valve opening calculation means 10 that determines the valve opening according to the output of the temperature comparison means 9, and valve opening output means 11. It is composed of

FIG. 3 is a flowchart of control in this embodiment.

FIG. 3 will be explained below.

At the same time as the power is turned on, the operating mode detecting means 14 detects the set operating mode, and the initial valve opening corresponding to each operating mode is outputted from the initial valve opening setting means 15. The valve opening degree of the electronic expansion valve 3 is changed.

Next, the set value Ts of the discharge temperature is determined by the target temperature setting means 8, and compared with the output of the temperature detection means 7 by the temperature comparison means 9. If the discharge temperature Td is higher than the target temperature T3, the valve opening degree is changed to Δ
Increase P. Further, when the discharge temperature Td is lower than the target temperature T$, the valve opening degree is decreased by ΔP. Δ is maintained for a period of time with the valve opening as it is, and the discharge temperature Td and target temperature T$ are compared again.

Repeat this action thereafter.

Effects of the Invention As described above, the present invention detects the temperature at a predetermined point in the refrigeration cycle using the temperature detection means, compares it with the output of the target temperature setting means using the temperature comparison means, and opens the valve according to the output of the temperature comparison means. In a control device that determines a valve opening degree by a degree calculation means and outputs it from a valve opening degree output means to change the valve opening degree of an electronic expansion valve, the operation mode detection means determines the initial valve opening degree of the electronic expansion valve as the operation mode. By providing an initial valve opening setting means that sets the initial valve opening according to the output of the detection means, it is possible to set the optimum initial valve opening for each operation mode, and the discharge temperature can be adjusted in a short time. Td can be brought closer to the target temperature T3,
This has the effect that the refrigeration cycle can be used efficiently.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle diagram showing one embodiment of the present invention;
The figure is a block diagram of the control device of the present invention, FIG. 3 is a flowchart showing the control contents of the control device, FIGS. 4 and 5 are refrigeration cycle diagrams of the conventional example, and a block diagram of the control device, and FIG. is a flowchart showing the control contents of a conventional example. 1... Compressor, 2... First heat exchanger, 3... Electronic expansion valve, 4... Second heat exchanger, 7...Temperature detection means, 8...
・Target temperature setting means, 9...Temperature comparison means, 1
0... Valve opening calculation means, 11... Valve opening output means, 13... Four-way valve, 14...
- Operation mode detection means, 15... Initial valve opening setting means. Name of agent: Patent attorney Toshio Nakao (3rd person)
Figure 2 Figure Figure Figure Figure

Claims (1)

[Claims] Compressor, first heat exchanger, four-way valve, electronic expansion valve, second
A refrigeration cycle is configured with a heat exchanger, etc., the temperature at a predetermined point of the refrigeration cycle is detected by a temperature detection means, the output of the target temperature setting means is compared with the temperature comparison means, and the temperature is determined according to the output of the temperature comparison means. In the control device, the valve opening degree is determined by the valve opening degree calculation means, and the valve opening degree is outputted from the valve opening degree output means to change the valve opening degree of the electronic expansion valve, comprising: an operation mode detection means;
A control device for an electronic expansion valve, comprising an initial valve opening setting means for setting an initial valve opening of the electronic expansion valve to an initial valve opening according to an output of the operation mode detecting means.