An air conditioning system for an electric vehicle includes a refrigerant E-compressor made up of a centrifugal compressor and an electric motor for driving the compressor. The housing of the compressor defines a coolant passage for liquid coolant. A coolant unit pumps liquid coolant through the coolant passage during normal AC system operation to cool the motor. A method for preventing or mitigating harmful effects of liquid refrigerant being ingested by the compressor includes determining whether liquid refrigerant is likely present in the compressor inlet; if so, a heating unit raises the temperature of the liquid coolant to thereby heat and evaporate any liquid refrigerant before starting the compressor. Once the danger of liquid refrigerant is passed, the compressor is started and the heating unit is deactivated.

A method for 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 speed of the refrigerant compressor; determining a refrigerant volumetric efficiency; and determining a refrigerant mass flow based on the refrigerant volumetric efficiency.

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.

A method for monitoring a refrigerant fill-quantity of a refrigeration machine, which includes a compressor for compressing the refrigerant, an expansion device for relieving the pressure of the refrigerant, a high-pressure heat exchanger through which the refrigerant is passed after compression by the compressor to transfer heat to a heat ex-change medium, and a low-pressure heat exchanger through which the refrigerant is passed after pressure relief by the expansion device, to absorb heat from the heat ex-change medium or a further heat exchange medium. Fill level information relating to the refrigerant fill-quantity is determined as a function of a plurality of operating parameters, the fill level information is determined independently from the temperature of the refrigerant after compression by the 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 method and system are provided and include determining a sensed condition. When the sensed condition is below a first threshold and above a second threshold, the second threshold being less than the first threshold, a flow of coolant is started in a coolant loop comprising a first portion of a first heat exchanger. A flow of refrigerant is started in a refrigerant loop by starting a compressor within the refrigerant loop at a first speed.

An embodiment of detecting a refrigerant leak in a climate control system includes (a) determining that the climate control system is in a deactivated and equalized state. In addition, the method includes (b) comparing an average pressure of a refrigerant of the climate control system to a saturated vapor pressure of the refrigerant at an average temperature within the climate control system, in response to (a). Further, the method includes (c) detecting a refrigerant leak based at least in part on (b).