There is described an air conditioning system with a refrigerant circuit, wherein the air conditioning system includes a leakage detection system. The leakage detection system comprises a room temperature sensor, an inlet temperature sensor for detection of a refrigerant temperature at a refrigerant inlet of a refrigerant evaporator, and an outlet temperature sensor for detection of a refrigerant temperature at a refrigerant outlet of the refrigerant evaporator. The sensors (34, 36, 40) are coupled with a calculating unit. In addition, there is described a method for leakage detection, in which a room temperature of the room to be air-conditioned is detected before the refrigerant evaporator on an air inlet side, a refrigerant inlet temperature is detected at the refrigerant inlet of a refrigerant evaporator, and a refrigerant outlet temperature is detected at a refrigerant outlet of the refrigerant evaporator.

Disclosed therein are a heat pump system for a vehicle and a method of controlling the heat pump system, which determines that frosting begins on an exterior heat exchanger and carries out a defrosting control if a difference value between outdoor temperature and refrigerant temperature of an outlet side of the exterior heat exchanger is above a frosting decision temperature in a heat pump mode, thereby increasing frost-prevention and defrosting effects and enhancing heating performance and stability of the system because the system recognizes the beginning of frosting on the exterior heat exchanger at a proper time so as to carry out the defrosting control.

A method of controlling the refrigerant pressure in an ambient heat exchanger of a refrigerant circuit, particularly a heat pump circuit, for vehicles, in which the current temperature and the current humidity of the ambient air is measured, the current dew point temperature of the ambient air is determined from the measured temperature and humidity, and if the ambient air temperature is below 0° C. the refrigerant pressure in the refrigerant circuit is controlled by adjusting the rotational speed of a refrigerant compressor of the refrigerant circuit, the flow cross-section of a controllable expansion element of the refrigerant circuit and/or the ambient air volume flow flowing around or through the ambient heat exchanger, such that the temperature of the ambient heat exchanger is greater than the dew point temperature.

There is disclosed an air-conditioning apparatus for vehicle which is capable of selecting an appropriate operation mode while inhibiting the operation mode from being unnecessarily changed, and achieving rapid and stable vehicle interior air conditioning. A controller has respective operation modes of a heating mode, a dehumidifying and heating mode, a dehumidifying and cooling mode, and a cooling mode, and selects and executes these operation modes. The controller has a dehumidifying and heating mode maximum radiator temperature MAP and a dehumidifying and cooling mode maximum radiator temperature MAP. The controller selects an operation mode in which a radiator target temperature TCO is achievable by heat radiation in a radiator 4 with reference to each MAP, on startup or at a time of change of the operation mode.

An abnormality diagnosis device that performs an abnormality diagnosis on a blower system that sends air to a plurality of air receiving objects obtains a target operating state of an airflow control device that controls airflow to the air receiving objects, obtains a temperature detected by a temperature sensor that detects a first temperature as a temperature of air fed to a first air receiving object as one of the air receiving objects or a temperature of the first air receiving object, estimates the first temperature, based on the target operating state of the airflow control device, and performs abnormality diagnosis on the airflow control device. The abnormality diagnosis device determines that there is an abnormality in the airflow control device, when a difference between the detected first temperature and the estimated first temperature is equal to or larger than a predetermined first reference value.

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.

A method and a correspondingly designed device are provided for controlling or regulating a coolant circuit of an air conditioning system, which includes at least one compressor, at least one condenser or gas cooler, and at least one evaporator. A controllable coolant expansion device is connected to the coolant inlet of the evaporator. It is detected when the coolant circuit is under filled with a coolant and, when an under filling of the coolant is detected, the control strategy of the expansion device is changed.

A vehicle air conditioner capable of making a determination that the dehumidification is unnecessary in a vehicle interior early to make a prompt transition from a dehumidifying mode to a heating mode and reduce power consumption is provided. A control device executes a heating mode to let a refrigerant discharged from a compressor 2 radiate heat in a radiator, decompress the refrigerant, and then let the refrigerant absorb heat in an outdoor heat exchanger 7, and a dehumidifying mode to let the refrigerant flow into the outdoor heat exchanger without flowing to the radiator to radiate heat therein, decompress the refrigerant, and then let the refrigerant absorb heat in a heat absorber 9 and let an auxiliary heater 23 generate heat. The control device shifts from the dehumidifying mode to the heating mode on the basis of the heat absorber suction air temperature Tevain being lowered more than a target heat absorber temperature TEO.

A vehicle heating, ventilating, and air conditioning (HVAC) system can be configured to reduce and/or prevent condensation build up on one or more elements of the system. Subsequent to a power state of the vehicle being switched from an active state to an inactive state, a fresh mode air source can be selected as an intake for a blower. It can be determined whether an ambient temperature is greater than or equal to a predetermined temperature. It can then be determined whether the compressor was in operation prior to the vehicle having been switched from the active state to the inactive state. It can be determined whether a temperature of an evaporator of the HVAC system is rising. If it is determined that the ambient temperature is greater than or equal to the predetermined temperature value, that the compressor was in operation prior to the vehicle having been switched from the active state tot eh inactive state, and that the temperature of the evaporator is rising, a blower can be activated to blow air from the fresh mode air source across the evaporator.

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.