Automobile air-conditioner having improved control characteristics

Claim 1

An automobile air-conditioner comprising a compressor with variable discharge capacity for compressing a refrigerant; a refrigerant circulation circuit placed in a ventilation duct and including at least one of a heat sink adapted to absorb heat during cooling and a radiator adapted to provide heat transfer to objects during heating; an outlet temperature sensor for sensing the air temperature at an outlet of said at least one of the heat sink and the radiator as a sensed outlet temperature; a room temperature sensor for sensing the temperature inside the automobile as a sensed room temperature; an outside air temperature sensor for sensing the temperature outside the automobile as a sensed outside air temperature; and a room temperature setting unit for use in setting the room temperature to a desired temperature, wherein the automobile air-conditioner further comprises: a first arithmetic operating unit that carries out an arithmetic operation according to at least the sensed room temperature, the sensed outside air temperature, and the desired temperature, to obtain a target temperature; a second arithmetic operating unit that carries out an arithmetic operation for predicting the rotation speed of the compressor with a predetermined feed-forward arithmetic expression to obtain a predicted rotation speed; and a third arithmetic operating unit that carries out an arithmetic operation with an arithmetic feedback control expression including the predicted rotation speed and a deviation between the target temperature and the sensed outlet temperature to obtain the rotation speed of the compressor, the compressor being controlled according to the rotation speed calculated by the third arithmetic operating unit.