A refrigeration cycle device has a cooling heat exchanger, an evaporation-pressure control valve, an inside-air ratio adjuster, and a controller. The evaporation-pressure control valve controls an evaporation pressure of a refrigerant in the cooling heat exchanger. The inside-air ratio adjuster changes a ratio of an inside air to an entire volume of the air exchanging heat with the refrigerant in the cooling heat exchanger. The controller controls the inside-air ratio adjuster. The evaporation-pressure control valve increases the evaporation pressure of the refrigerant as a flow rate of the refrigerant flowing through the evaporation-pressure control valve increases. The controller, in a first mode, increases the ratio of the inside air as an evaporation temperature of the refrigerant in the cooling heat exchanger falls.

There is disclosed a vehicle air conditioning device which inhibits generation of noise in a solenoid valve 30 disposed on an inlet side of a radiator 4 and improves durability of the solenoid valve. A second operation mode is executed to shut off an outdoor expansion valve 6, close the solenoid valve 30, open a solenoid valve 40 and thereby send a refrigerant discharged from a compressor 2 through a bypass pipe 35 to an outdoor heat exchanger 7. When a first operation mode to open the solenoid valve 30 and close the solenoid valve 40 and thereby send the refrigerant to the radiator 4 is shifted to the second operation mode, a controller opens the solenoid valve 30 at a timing to stop the compressor 2.

The present invention relates to an air-conditioner system for a vehicle and a method for controlling the same, and more particularly, to an air-conditioner system for a vehicle and a method for controlling the same which can change a target superheat degree depending on variation in an amount of refrigerant discharged from a compressor, namely, gradually decrease the target superheat degree by stages as the amount of refrigerant discharged from the compressor decreases, and control an electronic expansion valve based on the target superheat degree dropping by stages, thereby preventing performance degradation of an air conditioner and stabilizing the system by restraining a change in the superheat degree in an area where an amount of refrigerant discharged from a compressor varies.

A method operating a refrigeration system with a heat pump function for a motor vehicle with an at least partially electric drive. The refrigeration system has a refrigerant compressor; a first heat exchanger; at least one further heat exchanger; a sensor device arranged upstream of the refrigerant compressor on the low-pressure side for detecting a first refrigerant pressure and/or a first refrigerant temperature; a sensor device arranged downstream of the refrigerant compressor on the high-pressure side for detecting a second refrigerant pressure and/or a second refrigerant temperature. The method includes detecting the first refrigerant pressure and/or the first refrigerant temperature; detecting the second refrigerant pressure and/or the second refrigerant temperature; detecting a rotational speed of the refrigerant compressor; determining a refrigerant volumetric efficiency; and determining a refrigerant mass flow based on the refrigerant volumetric efficiency.