Automotive air conditioner

A control system for an automotive air conditioner, comprising:

• a plurality of temperature sensors that sense temperatures at predetermined automobile locations, and generate temperature signals in response thereto;
• a controller that is connected to the sensors, and that is programmed to determine a first target cooling degree according to air-conditioning environmental factors necessary for conditioning air in a passenger compartment, to determine a second target cooling degree corresponding to a temperature level for ensuring oil return performance, and to select said first target cooling degree or said second target cooling degree, whichever is smaller, as a target cooling degree;
• a post-evaporation temperature sensor that detects a degree of actual air cooling by the air conditioner unit;
• and
• the controller being programmed control a rate of refrigerant discharge from the air conditioner so that a degree of actual air cooling detected by said post-evaporation temperature sensor will meet a target cooling degree selected by said controller.

A method of controlling an automotive air conditioner, comprising the steps of:

• introducing air into a motor vehicle passenger compartment;
• conditioning air to be blown into a passenger compartment via a refrigerating cycle system that includes a cooling heat exchanger for cooling the air by heat exchange with a refrigerant, and a compressor that compresses the refrigerant fed from the cooling heat exchanger, and that discharges the compressed refrigerant to the heat exchanger;
• determining a first target cooling degree according to air-conditioning environmental factors;
• determining a second target cooling degree corresponding to a temperature level for ensuring oil return performance;
• selecting one of the first and second target cooling degrees as a target cooling degree;
• detecting a degree of actual air cooling by the air conditioner;
• and
• controlling a rate of refrigerant discharge from the compressor so that a degree of actual air cooling detected at the step of detecting a degree of actual air cooling will meet a target cooling degree selected at the step of selecting one of the first and second target cooling degrees.