Evaluation of Fixed Displacement Compressors for Control Logic Formulation of External Variable Displacement Compressors

The aim of this paper is to analyze the test performance data of fixed displacement compressors in vehicle level tests and identify the functioning regimes wherein the climate control unit forces the compressor to stop intermittently owing to low icing temperatures being reached at evaporator. The exercise provides a deeper insight to compressors operation as well as overall performance that assists in formulation of control strategy and various operating inputs necessary for variable displacement compressors to function as a replacement to fixed displacement compressors. The test data is used to arrive at variable duty cycle for EVDC that ensures smooth operation while yielding benefits of silent operation, lower power consumption and better cabin comfort inside vehicle. The test data used as benchmark was further used to arrive at startup and shutdown strategies for EVDC’s and same was incorporated in control logic developed for hardware controller that supervises the operation of EVDC’s.