An air-conditioning device includes: a frost formation determination unit configured to determine a frost risk state of an outdoor hot exchanger based on an accumulated time wherein a difference between a temperature detected by an outdoor air temperature detector and a temperature detected by a coolant temperature detector is the same or greater than a frost temperature difference; and an operation control unit configured to control a compressor and a blower so that air led into the cabin reaches a target blowout temperature set based on a required heating performance, and to execute a regular heating operation. In the event of the frost formation determination unit determining the frost risk state, the operation control unit is configured to execute a frost suppression operation wherein the air flow amount by the blower is increased while the target blowout temperature is decreased in comparison with the regular heating operation.

There is disclosed a vehicle air conditioner which is capable of enlarging an effective range of a dehumidifying and heating mode to environmental conditions and smoothly dehumidifying and heating a vehicle interior. A vehicle air conditioner 1 executes a dehumidifying and heating mode in which a controller lets a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, and decompresses the refrigerant by which heat has been radiated and then lets the refrigerant absorb heat in a heat absorber 9 and an outdoor heat exchanger 7, the controller decreases an outdoor blower voltage FANVout of an outdoor blower 15 and decreases an air volume into the outdoor blower 15 in a case where a temperature Te of the heat absorber 9 is high even when the controller adjusts a valve position of an outdoor expansion valve 6 into a lower limit of controlling in a situation in which a temperature TCI of the radiator 4 is satisfactory.

Methods and systems for providing control of a heat pump of a motor vehicle are presented. In one operating mode, speed of a heat pump compressor is controlled responsive to an outlet pressure of the heat pump compressor. In a second operating mode, speed of the heat pump compressor is controlled responsive to a pressure ratio between an inlet and an outlet of the heat pump compressor.

A method for controlling a refrigeration system of a vehicle includes a circuit containing a refrigerant, a compressor, and first and second evaporators which are connected in parallel to the compressor, and a first expansion valve arranged upstream the first evaporator that regulates a pressure drop of the refrigerant before the first evaporator, and a second expansion valve arranged upstream the second evaporator that regulates a pressure drop of the refrigerant before the second evaporator, and a condenser arranged downstream the compressor between the compressor and the first and second expansion valves. The method includes controlling a total opening of the first expansion valve and the second expansion valve, based on a temperature and a pressure of the refrigerant which refrigerant temperature and refrigerant pressure are measured downstream the first and second evaporators at a position between the first and second evaporators and the compressor.

A heating, ventilation, and air-conditioning (HVAC) system in a hybrid or battery-electric vehicle is provided. The HVAC system includes a compressor that has its own dedicated motor to control its speed. The compressor includes an inlet pressure sensor to determine and output the suction pressure, and an outlet pressure sensor to determine and output the discharge pressure of the compressor. At least one controller can be programmed to determine the discharge-to-suction pressure ratio, and limit the operating speed of the compressor in response to the ratio exceeding a pressure-ratio-threshold. The pressure-ratio-threshold can vary based on ambient air temperature. In the event an inlet pressure sensor is not available, the operating speed of the compressor can be reduced in response to the outlet pressure exceeding an ambient-temperature-based variable threshold.

The purpose of the present invention is to provide a vehicle air conditioning system and a control method of the vehicle air conditioning system which enable detecting leaks of flammable refrigerant without requiring a separate sensor. This vehicle air conditioning system is provided with: a refrigeration cycle for cooling (23); a heat pump cycle for heating (33); a refrigerant that is very flammable, has an explosive range near room temperature, and circulates in the refrigeration cycle for cooling (23) and the heat pump cycle for heating (33); an outside temperature sensor (44) which detects the outside temperature; a pressure sensor (49) which detects the refrigerant pressure; and a control device which calculates the refrigerant density, which is the density of refrigerant, on the basis of the outside temperature and the pressure, and determines whether or not the refrigerant density has fallen below a prescribed threshold value which is based on the amount of sealed refrigerant, the total volume in the refrigeration cycle for cooling (23) and in the heat pump cycle for heating (33), the volume of the vehicle cabin, the standard density of the atmosphere, and the explosive limit of the refrigerant.

Systems and methods for heating and cooling a vehicle are disclosed herein. In one embodiment, a method for heating and cooling the vehicle includes: running a compressor of an air-conditioning system; and sensing the temperature inside the cab of the vehicle. The method further includes, closing a path of refrigerant to the compressor by a solenoid valve, pumping-down refrigerant by the compressor, and deactivating the compressor when a lower set point of the temperature inside the cab is reached. The method also includes opening the path of refrigerant to the compressor by a solenoid valve, sensing pressure of refrigerant at an inlet of the compressor by a pressure sensor, and activating the compressor based on a signal from the pressure sensor when an upper set point of temperature inside cab is reached.

Methods and systems for providing control of a heat pump of a motor vehicle are presented. In one operating mode, speed of a heat pump compressor is controlled responsive to an outlet pressure of the heat pump compressor. In a second operating mode, speed of the heat pump compressor is controlled responsive to a pressure ratio between an inlet and an outlet of the heat pump compressor.

In a refrigeration cycle device, a variable throttle mechanism is provided in a refrigerant passage that connects an evaporator and a compressor, and is configured to be capable of changing a passage cross-sectional area of the refrigerant passage. A radiator includes a plurality of tubes and a header tank. The plurality of tubes, through which the refrigerant discharged from the compressor flows, are stacked in a stacking direction. The header tank is provided at an end side in a longitudinal direction of each of the plurality of tubes and communicates with the plurality of tubes. A tank interior space of the header tank is partitioned into a plurality of sections that are arranged in the stacking direction. The header tank includes an opening/closing mechanism configured to open or close a communication portion that causes adjacent ones of the plurality of sections to communicate with each other.

A thermal management system, a method of controlling the same, a compressor included in the same in which the thermal management system and the method of controlling the thermal management system determine whether the current state is a low-refrigerant state in which a refrigerant amount is smaller than a reference refrigerant amount on the basis of a degree of superheat or a degree of supercooling detected from a pressure and temperature of a refrigerant when a battery thermal management mode is operated and operations of cooling and heating a vehicle interior do not operate. The compressor is included in the thermal management system and configured as an electric compressor configured to be controlled by the control method. Therefore, it is possible to easily recognize whether the current state is the low-refrigerant state in which the refrigerant amount is smaller than the reference refrigerant amount.