Control strategy of a variable displacement compressor operating at super critical pressures

A method for controlling an air conditioning system for cooling a vehicle passenger compartment, the method comprising:

• directing air conditioned air into the vehicle passenger compartment using an air duct;
• circulating a refrigerant through a refrigerant circuit wherein the circuit has a first portion exposed to the air within the air duct and a second portion exposed to air external of the passenger compartment;
• compressing the refrigerant using a variable displacement compressor, wherein the compressor has a control valve for regulating refrigerant flow;
• and
• controlling the flow of refrigerant through the refrigerant circuit and the compressor using a controller by actuating the control valve until a predetermined interior passenger compartment climate is achieved.

An air conditioning system for cooling a vehicle passenger compartment, the system comprising:

• an air duct for directing air conditioned air into the vehicle passenger compartment;
• refrigerant circuit for circulating a refrigerant, wherein a first portion of the circuit is exposed to the air duct and a second portion of the circuit is exposed to air external of the vehicle passenger compartment;
• a variable displacement compressor in fluid communication with the refrigerant circuit, wherein the compressor has a first electronic control valve for regulating refrigerant flow between a compressor crankcase and a compressor discharge chamber and a second electronic control valve for regulating refrigerant flow between the compressor crankcase and a compressor suction chamber;
• and
• a controller in electrical communication with the variable displacement compressor for controlling refrigerant flow and a displacement of the compressor by actuating the first and second electronic control valves.