To properly control the load of a variable displacement compressor used for an air conditioner.
Based on the determination of a compressor control means 13 which receives various types of information by a control device 10, a control signal feed means 15 provides, through a solenoid drive means 11, pulse signals by frequencies which are different depending on whether the control is air conditioner control or compressor load control to the solenoid 211 of a displacement control valve 21 by a variable displacement compressor 20. The displacement control valve 21 is controlled, in one air conditioner control, by an energizing current smoothened by the inductance of the solenoid by the on/off with high frequency pulses and, in the other compressor load control, as an opening valve of two on/off position control with low frequency pulses irrespective of the suction pressure of a pressure sensing mechanism 213. The set values in both controls are determined by the pulse duty ratios of drive frequencies, and in the compressor load control, the compressor control means 13 changes the duty controls and controls a compressor torque T to come within a specified range.
Kenho Ikeda
Keisuke Yamamoto