An air conditioning system

The present invention relates to an air conditioning system for use in a motor vehicle powered by an internal combustion engine, comprising an electric motor powered by a battery; a capacity variable compressor arranged to be powered by at least one of said internal combustion engine and said electric motor; and a control unit that controls the driving of said compressor, wherein said control unit is configured to execute driving said compressor by only said electric motor at a predetermined capacity of said compressor for a first given time when said combustion engine is under an idling stop; driving said compressor by both said combustion engine and said electric motor upon expiration of said first given time for a second given time; increasing said predetermined capacity of said compressor upon expiration of said first given time; stopping driving of said compressor by said electric motor upon expiration of said second given time, so that thereafter said compressor is driven only by said combustion engine; and further increasing said predetermined capacity of said compressor till achievement of a predetermined high capacity of said compressor.