JPS6023263B2 - Air conditioner control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for an air conditioner equipped with a compressor of variable capacity.

In a compressor equipped with a variable capacity compressor, since the indoor temperature is low when heating operation is started, operation is started at high capacity due to the action of the indoor thermostat.

However, if the outside air temperature is high, the high pressure side may become too high before the room temperature is set to the set temperature. Therefore, in the past, a refrigeration cycle was configured with a gas injection circuit, and gas injection was used for high capacity operation, and gas injection was stopped for low capacity operation, so-called high capacity/low capacity switching. The ability was controlled by. However, in the above control system, the variable range of capacity is small, and the rise in high pressure cannot be sufficiently reduced.

Therefore, in addition to the above-mentioned control, the high pressure is lowered by lowering or stopping the fan rotation speed of the evaporator during heating in the outdoor heat exchanger, or by controlling the amount of heat absorbed. However, with this method, the low pressure decreases, the difference between high and low pressures increases, and the compressor needs to compress the gas from low pressure to high pressure, which increases the input and reduces compression efficiency. This invention was made based on the above circumstances, and its purpose is to stop gas injection when an overload is detected during high-capacity operation during heating, and to A control system for a heat pump air conditioner that allows low capacity operation by returning part of the gas cold soot during compression to the suction side and switching to lease, allowing for a wide range of capacity changes and sufficiently suppressing high pressure rises. This is what we are trying to provide.

The present invention will be explained below based on an embodiment shown in the drawings.

In FIG. 1, reference numeral 1 denotes a variable capacity compressor, the discharge port of which is connected to an outdoor heat exchanger 3 via a four-way valve 2. The outdoor heat exchanger 3 is connected to a liquid tank 5 via a check valve 4, and further connected to an indoor heat exchanger 7 via a pressure reducing device such as a capillary tube 6.
Further, this indoor heat exchanger 7 is connected to the suction port of the compressor 1 via the four-way valve 2 described above. Furthermore, an expansion valve 8 is provided in parallel with the series circuit of the check valve 4 and the IJ liquid tank 5, and the liquid tank 5 and the compressor 1
A gas injection circuit 11 having a capillary 9 and a first capacity control solenoid valve 10 is connected in the middle between the boat la and the boat la. Furthermore, the suction side of the compressor 1 has a second capacity control solenoid valve in the middle! 2 to the boat la of the compressor 1. In addition, 14 senses the indoor temperature and turns on and off.
15 is a high voltage switch as a load detection means. FIG. 2 is an electric circuit diagram, and 16 is a cold neighbor changeover switch. A two-step indoor thermostat 14 is connected to one terminal of the waist changeover switch 16, which has a high temperature side contact 14a, and the other terminal has a low temperature side contact 14b. In addition, the low salt side contact 14
One fixed terminal 17a of b is connected to the first capacity control solenoid valve 101 via the high pressure switch 15, and the other fixed terminal 17b
is connected in series to the second capacity control solenoid valve 12.
Next, the operation of the above embodiment will be explained.

First, during heating operation, since the indoor temperature is low at startup, the high temperature side and low temperature side contacts 14 of the indoor thermostat 14
a and 14b are on the L side, and the high voltage switch 15 is also on the ■ side. Therefore, when the compressor 1 is started, the first capacity control solenoid valve 10 is energized, and the gas injection circuit 1
Gas is injected into the compressor 1 via 1. For this reason, the compressor 1 is injected into the gas being compressed to increase the amount of cooling discharged from the compressor 1, and high-capacity operation is started to heat the room. The high pressure may become too high before the set temperature is reached. In this case, the high pressure switch 16 is activated and
The first capacity control solenoid valve 10 is turned off and the second capacity control solenoid valve 12 is turned on. Therefore, the gas injection action is stopped and gas is returned from the compressor 1 to its suction side via the lease circuit 13,
A part of the soot gas during compression is drawn out and switched to low capacity. When the high pressure decreases, the contact point of the high pressure switch 15 changes to the ■ side again, and high capacity operation begins.After that, the room temperature rises while high capacity and low capacity paddy exchanging operations are performed. When the room temperature reaches a certain set value, the low temperature side contact 14 of the indoor thermostat 14
b changes from the L side to the H side, and from this point on, low capacity operation or low capacity operation is turned on and off. Note that when the outside air temperature is low, the high pressure becomes lower than the set pressure, and in this case, the indoor thermostat 14 causes continuous high capacity operation or high capacity/low capacity switching operation.

In the case of cooling, the cooling/heating changeover switch 16 is set to the cooling side, and only the high temperature side contact 14a of the indoor thermostat 14 operates, resulting in low capacity operation or ON/OFF. As explained above, in this invention, when a heating overload is detected, gas injection to the compressor is stopped and switching control is performed so that the gas injection is returned from the compressor to its suction side. The range of change in capacity can be made larger than in the case where the injection is stopped, and high pressure increases can be sufficiently suppressed, and high pressure decreases can be made faster.

Generally, gas injection increases capacity by about 10%, but simply stopping gas injection can only reduce capacity by about 10%, and often the overload condition cannot be resolved and the compressor is stopped. However, in this invention, by leasing gas cold soot from the compressor, it is possible to reduce the heating by about 20% compared to normal times, without having to stop the compressor. Overload conditions can be resolved while heating operation continues.

Therefore, it goes without saying that the control range can be widened depending on the load, but overload conditions can be quickly resolved without stopping the compressor, which reduces the number of times the compressor starts and stops, improving compressor reliability. In addition, since the compressor can be operated continuously without stopping, there is no sudden temperature change and comfort can be improved.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a refrigeration cycle showing one embodiment of the present invention, and FIG. 2 is an electric circuit diagram. 1... Compressor, 2... Four-way valve, 3...
... Outdoor heat exchanger, 6 ... Pressure reduction device, 7
... Indoor heat exchange, 10, 12 ... Capacity control solenoid valve, 11 ... Gas injection circuit, 13 ... Release time, 15 ... High pressure switch ( load detection means). Figure 1 Figure 2

Claims (1)

[Claims] 1. In a control system for an air conditioner in which a compressor, an outdoor heat exchanger, a pressure reducing device, and an indoor heat exchanger are connected in sequence and refrigerant that is being decompressed during heating is injected into the compressor, the load detection means is Therefore, when a heating overload is detected, gas injection to the compressor is stopped, and conversely, a switching control is performed so that a part of the gas refrigerant that is being compressed is returned from the compressor to its suction side. A control method for air conditioners.