To provide a control method of a variable displacement compressor capable of smoothly controlling the variable displacement compressor without requiring electric current measurement of an electromagnetic coil when starting and when changing an engine load.
The auxiliary machine ambient temperature in an engine room is measured by a water temperature sensor or an outside air temperature sensor, and a carrying electric current is estimated by predicting a resistance change in the electromagnetic coil 23, and the duty ratio of an input electric current to the electromagnetic coil 23 is calculated. Since the carrying electric current reduces when resistance increases with the lapse of time by self-heating of the electromagnetic coil 23, the calculated duty ratio is corrected by estimating a change in the carrying electric current of the electromagnetic coil 23 on the basis of operation time of the variable displacement compressor measured by a timer 29. Thus, the duty ratio of the carrying electric current to the electromagnetic coil 23 can be kept constant, and the variable displacement compressor can be controlled in a stabilized state.
Iwa Saki Kokuni
Kawamata Sumio
Masakazu Ito
Shunichi Takahashi
Toshio Takamatsu
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