Patent ID: 6484520
Filing Date: 2002-11-26
Classification: B60H,F04B,F25B

Abstract:
A displacement control apparatus for controlling the discharge displacement of a variable displacement compressor, wherein the compressor is incorporated in a refrigerant circuit of a vehicle air conditioner and includes a drive shaft, wherein a load torque is imposed on the drive shaft by driving the drive shaft with an external drive source, and a change in the load torque reflects the control of the discharge displacement, the displacement control apparatus comprising:a control valve for changing the displacement of the compressor by changing the valve opening degree; a first controller, which is provided outside the compressor, for sending a torque setting signal, which indicates a set torque for controlling the discharge displacement of the compressor; and a second controller for receiving the torque setting signal sent from the first controller, wherein the controller computes an index for changing the opening degree of the control valve based on the torque setting signal so that the load torque of the compressor is changed to the set torque, wherein the index indicates the pressure difference between the pressures at two pressure monitoring points in the refrigerant circuit, wherein the opening degree is changed by changing the pressure difference to a target pressure difference which corresponds to the set torque, and as a result, the control valve opening degree is controlled to change the displacement of the compressor.