Ejector refrigerant cycle device and control method thereof

An ejector refrigerant cycle device comprising:

• a compressor that draws, compresses and discharges refrigerant;
• a radiator that radiates heat of refrigerant discharged from the compressor;
• an ejector that has a nozzle portion for reducing pressure of refrigerant on a downstream side of the radiator to expand the refrigerant, a refrigerant suction port from which refrigerant is drawn by a high-velocity refrigerant flow jetted from the nozzle portion, a mixing portion in which the refrigerant jetted from the nozzle portion and the refrigerant drawn from the refrigerant suction port are mixed, and a diffuser portion which increases pressure of the mixed refrigerant from the mixing portion;
• an evaporator that evaporates refrigerant and flows out the evaporated refrigerant to the refrigerant suction port;
• a pressure abnormality detecting means that detects a pressure abnormality of a high-pressure refrigerant on an upstream side of the nozzle portion;
• and
• reducing means for reducing a pressure increasing amount of the mixed refrigerant in the diffuser portion of the ejector,
• wherein the compressor draws refrigerant on a downstream side of the ejector, and
• wherein when the pressure abnormality detecting means detects the pressure abnormality, the reducing means reduces a pressure increasing amount of the mixed refrigerant in the diffuser portion than that in a normal pressure state of the high-pressure refrigerant.