Variable displacement swash plate type compressor and control method

A variable displacement swash plate type compressor control method comprising:

• when a variable displacement swash plate type compressor is started which includes:
• a housing, a rotating shaft which is rotatably supported by the housing, a disk and a swash plate which rotate together with the rotating shaft, a pulley which receives mechanical power from a driving source and rotates, a field coil assembly which brings the disk into contact with the pulley when electric power is applied, a piston which reciprocates by the swash plate, and an inclination adjustment mechanism which adjusts an inclination angle of the swash plate with respect to the rotating shaft,
• a first determination step of determining a possibility that liquid refrigerant exists within the variable displacement swash plate type compressor;
• a first operation step of applying electrical power to the field coil assembly and of not applying current to an electronic control valve, when it is determined in the first determination step that the liquid refrigerant is highly likely to exist;
• a second determination step of comparing an elapsed period of time of operating in the first operation step with a predetermined reference time;
• and
• a second operation step of maintaining the electrical power applied in the first operation step to the field coil assembly and of applying current to the electronic control valve when it is determined in the second determination step that the elapsed period of time is greater than or equal to the predetermined reference time.