Automotive air conditioning system with automatic control of

Abstract

An automotive air conditioning system has refrigeration devices, heating devices and a single chip microcomputer. The refrigeration devices include a variable displacement refrigeration compressor drivingly connectable by an electromagnetic clutch to an automotive engine and a refrigerant evaporator disposed in an air duct, through which air is caused to flow by a blower. The heating devices include a heater core disposed downstream of the refrigerant evaporator, through which heated air is caused to flow, and an air mixing damper which regulates the quantity of air to be introduced into the heater core. A condition relating to the air conditioning operation such as the temperature of the vehicle is detected by a sensor. The microcomputer receives the signals from the sensor, calculates a required injection temperature, compares the required injection temperature and a preset standard temperature, a lower standard temperature and a higher standard temperature and produces operating signals. The operating signals manage the connection of the electromagnetic clutch, vary the displacement of the refrigeration compressor, regulate the degree of opening of the air mixing damper and control the rotating velocity of the blower.