Disclosed are climate systems for vehicles and methods for controlling the climate systems. In some implementations, a climate system includes: (1) a temperature sensor configured to measure a temperature within the compartment of the vehicle; (2) a first compressor powered by an engine of the vehicle to compress a refrigerant; (3) a second compressor driven by an electric motor to compress the refrigerant; and (4) a controller electrically coupled to the first compressor and the second compressor. The controller configured to: (1) calculate a thermal load of the compartment based on a difference between a desired temperature and a measured temperature; and, (2) based on the calculated load, selectively activate: (i) the engine, (ii) the first compressor, and/or (iii) the second compressor.

Methods and systems are provided for an air conditioning system. An example method of determining current through a compressor suction valve in a vehicle air conditioning (AC) system is provided, the AC system comprises an evaporator fan and the method includes determining the speed of the evaporator fan and determining the current through the suction valve based on the speed of the evaporator fan.

A reheating process for operating a cooling system having a heat pump function for a motor vehicle. The reheating process includes steps of determining a heat differential value by comparing a heat emission actual value at the heating register to a heat emission target value, and adjusting at least one operating setting of the cooling system, so that the power consumption in the cooling system is increased if the heat differential value is greater than 0 and less than a heat differential threshold value.

A refrigerant cycle device includes a compressor, a radiator, a first expansion valve, a second expansion valve, a first evaporator, a second evaporator, and a controller. The controller is configured to switch between a first evaporator priority control and a second evaporator priority control. During the first evaporator priority control, the controller controls a throttle opening of the second expansion valve based on at least one of a temperature of a first evaporator, a temperature of a refrigerant flowing through the first evaporator, and a temperature of an air having exchanged heat in the first evaporator. During the second evaporator priority mode, the controller controls the throttle opening based on a refrigerant state of the second evaporator. When the at least one of the temperatures is equal to or greater than a switching temperature, the second priority mode is switched to the first priority mode.

A filter monitoring system for a filter in a vehicle air conditioner includes a first temperature sensor to detect an air temperature of intake air drawn into an air conditioner case through the filter, a second temperature sensor to detect an evaporator temperature of the evaporator, and a processor coupled to the first and second temperature sensors and coupled to a memory. The processor is configured to calculate an actual change-rate of the evaporator temperature while a compressor is in operation, calculate an expected change-rate of the evaporator temperature based on the air temperature and operation levels of a blower and the compressor by using predetermined data with a properly functioning filter, calculate a degradation degree of the filter by comparing the actual change-rate to the expected change-rate, and output a signal indicating degradation of the filter upon determining that the degradation degree is out of an acceptable range.

A refrigerant circuit system includes a compressor configured to compress refrigerant, a condenser configured to cause the compressed refrigerant to radiate heat, first and second evaporators each configured to decompress and expand the heat-radiated refrigerant by regulating a valve opening degree, first and second evaporators provided in parallel and configured to cause the refrigerant, respectively decompressed and expanded by the first and second expansion valves, to absorb heat, and a controller configured to, based on first information related to a temperature of a first temperature regulated object, regulated by the first evaporator, second information related to a temperature of a second temperature regulated object, regulated by the second evaporator, and third information related to a degree of superheat of the refrigerant at an inlet of the compressor, control the valve opening degrees of the first and second expansion valves and a compression ratio of the refrigerant by the compressor.

There is disclosed a method of controlling an air-cargo transport refrigeration unit to regulate a compressor speed and a condenser fan speed. There is also disclosed a method of controlling an air-cargo transport refrigeration unit based on determining an in-flight condition of the refrigeration unit.

An air conditioner for a vehicle is provided which can realize suitable temperature control when having a plurality of evaporators even if the load in each evaporator fluctuates. An air conditioner 1 for a vehicle includes at least a compressor 2, a heat absorber 9 to evaporate a refrigerant, a refrigerant-heat medium heat exchanger 64, and a control device 11, and conditions air of a vehicle interior. The control device 11 calculates target numbers of revolutions TGNCc and TGNCcb of the compressor 2 required to control the temperature of the heat absorber 9 and the temperature of a heat medium cooled by the refrigerant-heat medium heat exchanger 64, respectively, and selects the maximum value of them to control the operation of the compressor 2.

A vehicle air-conditioning device is a heat pump type vehicle air-conditioning device including an external heat exchanger that performs heat exchange between refrigerant flowing the inside thereof and outside air. With the vehicle air-conditioning device, a controller functions as a temperature-difference calculation unit that calculates the temperature difference ΔT between the refrigerant in a refrigerant flow path on the exit side of the external heat exchanger and the outside air, and in addition, the controller functions as a frost formation determination unit that determines that frost formation is caused on the external heat exchanger on the basis of the elapsed time to of a state in which the temperature difference ΔT is equal to or larger than a frost-formation temperature difference at which the frost formation may be caused on the external heat exchanger.

A first sensor measures temperature at a first evaporator that cools a first zone. A second sensor measures temperature at a second evaporator that cools a second zone. A controller operates a compressor in a normal cooling mode or a single zone cooling mode. In the normal cooling mode, both the first zone and the second zone are cooled with the compressor operated by the controller in response to temperature measurements from one or both of the first sensor and the second sensor. In the single zone cooling mode, only the second zone is cooled with the compressor controlled by the controller in response to temperature measurements from the second sensor and the controller determining that the first evaporator has a low probability of accumulating frozen moisture on surfaces thereof, and in response to determining a high probability of accumulating frozen moisture on surfaces thereof the compressor is not operated.