A Microprocessor Controller and Sensor for Refrigerant Low Charge Detection in an Air Conditioning System

A patent pending microprocessor controller, detection algorithm and low cost sensor have been developed to accurately detect a refrigerant low charge state in mobile air conditioning systems. The device is intended to prevent damage to the air conditioning system compressor and was designed primarily for truck and bus applications although the principles may also be applied to automotive, agricultural, construction, mining equipment and stationary HVAC applications. The system uses a single, thermistor based refrigerant charge sensor, an optional high pressure transducer and a microprocessor controlled electronics module coupled with standard air conditioning system components to detect the presence or lack of refrigerant in the A/C circuit.