A New Method of Refrigerant Flow Control in Automotive Air Conditioning

摘要

This paper describes the improvement of refrigerant flow control method that uses an electronic expansion valve driven by a stepper in automotive air conditioning. It can make a quick response to the abrupt change in the refrigerant flow rate at the time of the automotive speed change and the thermostatic on/off operation. For the control of the electronic expansion valve, single chip is used for receiving input signal and generating output signal to control the opening of the electronic expansion valve. Experimental result shows that the new control method can be able to feed the adequate refrigerant flow into the evaporator under variation operation. The evaporator discharge temperature has dropped by approximately 3℃ as compared with that of the conventional PID control system.