Air conditioning apparatus for vehicle and its control method

摘要

A vehicle air conditioning apparatus includes a refrigerant circuit. The air conditioning apparatus is driven by an engine. The air conditioning apparatus includes a variable displacement compressor. An external information detector detects external information used for the air conditioning. An E/G-ECU controls the output of the power source. An A/C-ECU is connected to the E/G-ECU via a communication line. The A/C-ECU computes a target value of the displacement of the compressor based on the external information. The A/C-ECU sends the computed target value to the E/G-ECU. The E/G-ECU controls the displacement of the compressor based on the computed target value. This is capable of rapidly changing the discharge displacement in accordance with the driving condition of the engine.