To suppress the sudden temperature rise of refrigerant discharged from a compressor up to a threshold temperature or higher for the compressor right after starting a supercritical refrigerating cycle.
As target high pressure, normal target pressure Po1 for optimum control to be determined in accordance with the temperature of the refrigerant on the outlet side of a radiator and starting target pressure Po2 lower than the normal target pressure Po1 are set to be changed over. Within a predetermined time after starting the compressor, the starting target pressure Po2 is set to control the opening of an electric expansion valve. On the other hand, when a predetermined time passes after starting the compressor, the normal target pressure Po1 is set to control the opening of the electric expansion valve.
Takahiro Miura
Fumihiro Mizuno