JPS61140738A - Control device for air conditioner - Google Patents

Abstract

PURPOSE:To prevent an abnormal high pressure in the refrigerating cycle at the time of starting the heating mode operation so as to allow a smooth opera tion by adding a circuitry for counting the cumulative operating time to a circuitry that controls the speed of the room fan for the room side heat exchange to constitute a device that controls the room fan speed for a certain time period when the operating time exceeded a predetermined limit. CONSTITUTION:By making a judgment whether or not the delivery pressure is above the set value of a pressure switch 8, the operating time of an air conditioner is compared if the set pressure is exceeded. If it is less than the set time, the room fan 4 is operated as instructed by a room fan operation mode circuit 12. If the set time is exceeded, the room fan 4 is controlled to forcibly operated at its maximum speed. A comparison is made to make a judgment whether or not such a mode continued for a certain duration such as 30sec for example. When the certain duration has passed, the room fan 4 assumes a high, medium or low speed in response to the command from the room fan operation mode circuit 12. Further, resetting is allowed by the cumulative counting of operation time and operation time reset signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in air conditioners, and particularly to a control device for preventing an abnormal pressure rise at the start of heating operation.

27. Conventional configuration and its problems As a general air conditioner refrigeration cycle, the one shown in FIG. 2 is known. That is, during heating operation, the refrigerant sent out from the compressor 1 passes through the four-way valve 2 as shown by the arrow in the figure, heat exchanges in the indoor heat exchanger 3 in cooperation with the indoor fan 4, and then 5 to the outdoor heat exchanger 6, where it exchanges heat with the outdoor fan 7, passes through the four-way valve 2, and is sucked into the compressor 1 again.

In this refrigeration cycle, when the heating operation starts, the temperature of the indoor heat exchanger 3 is low and when the indoor fan 4 is operated,
Since cold air is blown out and a cold draft occurs, a method is generally used in which the indoor fan 4 is operated after waiting until the temperature of the indoor heat exchanger 3 becomes sufficiently high. A pressure switch 8 that detects the discharge pressure of the compressor 1 is used as a signal to delay the indoor fan 4, and when the discharge pressure reaches a certain value, the indoor fan 4 is started to operate according to a signal from the pressure switch 8. .

31. - Generally, a refrigeration cycle is provided with a high pressure cut switch 9 to prevent abnormally high system pressure.

FIG. 3 is a diagram showing the relationship between the elapsed time and the discharge pressure P at the start of the heating operation. At the start of the heating operation, the indoor fan 4 is stopped to prevent the aforementioned cold draft, the discharge pressure P rises, and the pressure switch is turned off. 8, the indoor fan 4 is driven (point a in the figure). In this case, the setting and value of pressure gas isochi 8 is generally 20 K91.
If crl G is appropriate and is lower than that, the indoor fan 4 will be driven before the temperature of the indoor heat exchanger 3 becomes sufficiently high, causing a cold draft. 1, 2
0KF! /crtlG or higher, no cold draft occurs, but there is a problem that the pressure rise is slow and it takes too much time to drive the indoor fan.

Next, the operation of the conventional air conditioner will be explained with reference to FIGS. 4 and 5. The control circuit 1o switches the operation mode of the air conditioner between cooling and heating in response to a signal from the operation mode circuit 11, and performs on/off control of the compressor 1. Further, a signal is given to the indoor fan operation mode circuit 12 to control the operation mode of the indoor fan 4. In order to perform these controls, signals from protective devices 13 such as a pressure switch 8 that detects the discharge pressure P and a high pressure cut switch 9 that detects abnormalities in the refrigeration cycle are read.

When a heating operation command is given, first, it is determined whether or not the protection device 13 such as the high voltage cut switch 9 that prevents abnormally high pressure mentioned above is activated, and if activated, the operation is stopped. , if there is no operation, the compressor 1 is operated.

Next, it is determined whether or not the discharge pressure P is equal to or higher than the set value 28 of the pressure switch 8. If it is less than the set value, this flow is repeated until the pressure reaches the set value 28 or higher. If the set value exceeds 28, the indoor fan 4 is operated with strong wind, weak wind, or breeze according to the indoor fan operation mode circuit 12.

In the above configuration, the indoor fan 4 is delayed until the discharge pressure P of the compressor 1 reaches a certain value at the start of heating operation, but if the inertia moment of the indoor fan 4 is large or the air When a filter (not shown) becomes clogged and the load on the indoor fan 4 increases, the pressure switch 8 is activated by the discharge pressure P, and even if the indoor fan 4 is driven, the desired air volume is not supplied to the indoor heat exchanger 3. However, the discharge pressure P continues to rise and reaches the set value of the high pressure cut switch 9, which is provided to prevent abnormally high pressure in the refrigeration cycle, resulting in a shutdown of the refrigeration cycle. This is particularly noticeable when the operation mode of the indoor fan 4 is set to a low air volume, such as weak wind or breeze.

OBJECT OF THE INVENTION Therefore, an object of the present invention is to prevent the above-mentioned abnormally high pressure in the refrigeration cycle at the start of heating operation, and to obtain smooth operation.

Structure of the Invention To achieve this object, the present invention provides a circuit that integrates the operation time of an air conditioner in a circuit that controls the speed of an indoor fan for an indoor heat exchanger based on a signal from a pressure filter that detects the discharge pressure of a refrigeration cycle. This is an air conditioner control device that forcibly controls the indoor fan speed for a certain period of time when the operating time exceeds a certain period of time.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. Components that are the same as those in the prior art example are given the same numbers and their explanations are omitted. FIG. 1 is a flowchart showing an embodiment of the present invention. The operation will be explained based on the block diagram of the control circuit shown in FIG. The basic part of this flowchart is the same as that in FIG. 5, and when a heating operation command is given from the operation mode circuit 11, it is determined whether or not the protection device 13 is activated, and if it is activated, stops operation, and if it is not operating, compressor 1 is operated.

Next, it is determined whether the discharge pressure P is equal to or higher than the set value 28 of the pressure switch 8. If it is less than the set pressure, the above-mentioned flow is repeated, and if the set pressure is equal to or higher than the set pressure 28, then the operation time of the air conditioner is compared. , set time Ts (for example, 76 hours, 1
50 hours), the indoor fan 4 performs strong operation 9 weak operation or gentle breeze operation as instructed by the indoor fan operation mode circuit 12. If the set time is 73 or more, the air filter installed in the indoor heat exchanger 3 is generally clogged, and as mentioned above, the air volume is insufficient and the pressure is set to 1 of the high pressure cut switch 9, which is a protection device. increases, so
The operation of the indoor fan 4 is forcibly controlled to the highest speed. Then, a comparison is made to see if this mode has been maintained for a predetermined time TFS or more, for example, 30 seconds, and when the predetermined time TFS or more has elapsed, the indoor fan 4 operates in strong wind, weak wind, or light wind according to a command from the indoor fan operation mode circuit 12. Further, the cumulative operation time can be reset by an operation time reset signal.

The control circuit 1o in the above embodiment uses a microcomputer, which has recently become easy to obtain, and the time setting circuit uses a ROM, so that the apparatus can be easily constructed.

Therefore, when the operating time of the air conditioner exceeds a certain time Ts, the increase in the discharge pressure P is minimized by forcibly setting the indoor fan operation mode circuit 12 to the maximum speed for a certain period σFS. This allows for smooth operation.

Effects of the Invention As is clear from the above explanation, the present invention includes a pressure switch that detects the discharge pressure of a compressor in a refrigeration cycle, a circuit that controls the speed of an indoor fan for an indoor heat exchanger, and an air conditioner. a circuit for accumulating operating time; and a control circuit for forcibly operating the indoor fan control circuit for a predetermined period of time using the pressure switch signal when the operating time of the air conditioner exceeds a predetermined time. This allows for smooth operation even when the air filter installed in the indoor heat exchanger is clogged or the inertia of the indoor fan is so strong that it takes a long time to reach the specified air volume when starting heating operation. effective.

[Brief explanation of the drawing]

Fig. 1 is a flowchart showing the operation of an embodiment of the present invention, Fig. 2 is a refrigeration cycle diagram of an air conditioner, Fig. 3 is a relationship diagram between elapsed time at the start of heating operation and discharge pressure 9 force, FIG. 4 is a block diagram of a control circuit showing an example of a conventional example, and FIG. 5 is a flowchart showing the operation of FIG. 4. 1... Compressor, 3... Indoor heat exchanger, 6 Old... Outdoor heat exchanger, 5... Throttle device, 2...・Four-way valve, 8...Pressure switch, 4
...Indoor fan. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Sweet Figure 4

Claims (1)

[Claims] Compressor, indoor heat exchanger, outdoor heat exchanger, throttling device,
A refrigeration cycle consisting of four-way valves connected in series, a pressure switch that detects the discharge pressure of the compressor in this refrigeration cycle, a circuit that controls the speed of the indoor fan for the indoor heat exchanger, and the operating time of the air conditioner. A control circuit for forcibly operating the control circuit for the indoor fan for a predetermined period of time by a signal from the pressure switch when the operating time of the air conditioner exceeds a predetermined period of time. An air conditioner control device characterized by: