Abstract: A refrigerant circuit with a passageway control mechanism is disclosed which includes a compressor, a condenser and an evaporator connected to each other in series. The passageway control mechanism is disposed between an outlet side of the evaporator and an inlet side of the compressor and operates to change the size of an opening area of a passageway therebetween responsive to the pressure difference between high and low pressure areas within the compressor.

Abstract: An automotive air conditioning system having a refrigeration circuit including a compressor, a condenser, an expansion valve, an evaporator, and an accumulator disposed serially and respectively is disclosed. A fan controls the air flow volume of the evaporator in accordance with the operation of a transfer switch. The expansion valve includes two orifices and an actuator which opens and closes one orifice. The actuator is electrically controlled in response to the operation of the transfer switch. The transfer swith correspondingly controls both the air flow across the evaporator and the refrigerant flow through the expansion valve. Therefore, an accumulator having a small volume can be used the expansion valve construction is simple.

Abstract: A slant plate type compressor, such as a wobble plate type compressor, with a variable displacement mechanism for use in a refrigeration circuit is disclosed. Two passageways communicate between the crank chamber and the suction chamber in the cylinder block. A bellows is disposed in a first passageway and controls communication between the crank chamber and the suction chamber in the first passageway. The bellows operates in accordance with the crank chamber pressure. A control valve is disposed in the second passageway and controls communication between the crank chamber and the suction chamber in the second passageway in response to signal from an external sensor. This configuration enables the compressor to be operated at maximum capacity when the refrigeration circuit is turned on until the temperature in the passenger compartment of a car reaches a desired temperature without input from the pressure in the crank chamber.