Air conditioner and control valve in variable displacement compressor

摘要

A control valve (200) controls the pressure in a crank chamber (5) of a compressor to change the displacement of the compressor. The compressor includes a discharge chamber (22), a suction chamber (21) and a supply passage (28), which connects the discharge chamber (22) to the crank chamber (5). The control valve (200) regulates the supply passage (28). The control valve (200) includes a valve body (43), a spool (54) and a solenoid (100). The valve body (43) adjusts the size of an opening in the supply passage (28). The spool (54) moves the valve body (43) in accordance with the difference (Pd-Ps) between the pressure in the discharge chamber (22) and the pressure in the suction chamber (21). The solenoid (100) urges the valve body (43) by a force, the magnitude of which corresponds to a supply of electricity. The urging force of the solenoid (100) represents a target value (TPD) of the pressure difference (Pd-Ps). The spool (54) moves the valve body (43) such that the pressure difference (Pd-Ps) seeks the target value (TPD). The control valve (200), which is located in the compressor, permits the compressor displacement to be accurately controlled regardless of a thermal load on a evaporator (33).