Patent ID: 7918097

Claim:
A method for controlling an air conditioning system that includes a condenser for condensing a refrigerant, a first expansion device for throttling the refrigerant passed through the condenser, a second expansion device for throttling the refrigerant passed through the first expansion device, an evaporator for evaporating the refrigerant passed through the second expansion device, a compressor for compressing the refrigerant passed through the evaporator and the refrigerant branched between the first expansion device and the second expansion device and injected into the compressor, an injection valve for adjusting the amount of refrigerant branched between the first expansion device and the second expansion device and injected into the compressor, and a control unit for controlling opening degrees of the first expansion device, the second expansion device, and the injection valve, the method comprising the steps of: a) initiating opening the injection valve and then, increasing an opening degree of the injection valve; and b) decreasing an opening degree of the first expansion device for a predetermined period of time and maintaining an opening degree of the second expansion device during performing the step a).