Control valve in variable displacement compressor

摘要

A control valve for a variable displacement compressor in refrigerant circuit permits the compressor displacement to be accurately controlled regardless of the thermal load on an evaporator. The refrigerant circuit includes a high pressure pipe, which extends between a discharge chamber of the compressor and a condenser. A first pressure monitoring point is located in the discharge chamber. A second pressure monitoring point is located in the high pressure pipe. A supply passage connects the second pressure monitoring point with a crank chamber of the compressor. The control valve is located in the supply passage and adjusts the opening size of the supply passage in accordance with the difference between the pressure at the first pressure monitoring point and the pressure at the second pressure monitoring point. The control valve includes a solenoid for determining the target value of the pressure difference. The control valve operates to maintain the determined target value.