Abstract: The value of an estimated drive torque is prevented from greatly differing from an actual drive torque of a variable displacement compressor immediately after a refrigerating cycle is started. A first estimated drive torque that is calculated based on a physical quantity other than the pressure of a refrigerant and increases with lapse of time after the variable displacement compressor begins to compress the refrigerant and a second estimated drive torque calculated using the pressure of the refrigerant are compared and the one with the value closer to the actual drive torque is employed as an estimated drive torque of the variable displacement compressor.

Abstract: When a compressor apparatus is operated at a maximum displacement for 60 minutes or longer, an ECU controls a pressure control valve to gradually change the refrigerant pressure in a swash plate chamber in a manner that gradually reduces the displacement of the compressor apparatus. In this way, it is possible to create a state, in which a relatively large pressure difference is created between a refrigerant inlet side and the swash plate chamber. Thus, refrigerant oil accumulated in the swash plate chamber can be returned to the refrigerant inlet side of the compressor apparatus at the time of gradually reducing the displacement of the compressor apparatus.

Abstract: When a compressor apparatus is operated at a maximum displacement for 60 minutes or longer, an ECU controls a pressure control valve to gradually change the refrigerant pressure in a swash plate chamber in a manner that gradually reduces the displacement of the compressor apparatus. In this way, it is possible to create a state, in which a relatively large pressure difference is created between a refrigerant inlet side and the swash plate chamber. Thus, refrigerant oil accumulated in the swash plate chamber can be returned to the refrigerant inlet side of the compressor apparatus at the time of gradually reducing the displacement of the compressor apparatus.

Abstract: A refrigerant cycle system includes a variable displacement compressor, and first and second evaporators disposed in parallel. In the refrigerant cycle system, it is determined whether a refrigerant flow amount from the compressor is in a low flow amount area when first and second blowers for blowing air to the first and second evaporators are operated at the same time. When it is determined that a predetermined time passes after the refrigerant flow amount is determined to be in the low flow amount area, the operation of the compressor is forcibly switched between a large discharge capacity and a small discharge capacity. Accordingly, it can prevent oil returning to the compressor from being short due to the operation of the compressor in the low flow amount area.

Abstract: A refrigerant cycle system includes a variable displacement compressor, and first and second evaporators disposed in parallel. In the refrigerant cycle system, it is determined whether a refrigerant flow amount from the compressor is in a low flow amount area when first and second blowers for blowing air to the first and second evaporators are operated at the same time. When it is determined that a predetermined time passes after the refrigerant flow amount is determined to be in the low flow amount area, the operation of the compressor is forcibly switched between a large discharge capacity and a small discharge capacity. Accordingly, it can prevent oil returning to the compressor from being short due to the operation of the compressor in the low flow amount area.