Abstract: A system and method for sensing and controlling the temperature of a heating, ventilation and air conditioning (HVAC) system utilizes an infrared sensor. The infrared sensor is used to detect temperature over several different areas on an evaporator surface on which a cold spot may occur. More preferably, the infrared sensor continuously scans the whole surface on the air outlet side of the evaporator. The sensed temperature is used to detect any cold spots that may dynamically form on the evaporator surface. The system is controlled in response to the detected temperature.

Abstract: A system and method for sensing and controlling the temperature of a heating, ventilation and air conditioning (HVAC) system utilizes an infrared sensor. The infrared sensor is used to detect temperature over several different areas on an evaporator surface on which a cold spot may occur. More preferably, the infrared sensor continuously scans the whole surface on the air outlet side of the evaporator. The sensed temperature is used to detect any cold spots that may dynamically form on the evaporator surface. The system is controlled in response to the detected temperature.

Abstract: A method for detecting a low level of refrigerant circulating through a motor vehicle refrigerant circuit having a compressor (12), a condenser (14), an evaporator (16), and an accumulator (18), includes detecting a partial loss of a refrigerant fluid by measuring the temperature difference of the refrigerant fluid between an evaporator inlet and an evaporator outlet. The method further includes detecting a complete loss of refrigerant by measuring the pressure of the refrigerant in the liquid phase between the condenser (14) and the evaporator (16). The temperature and pressure measurements are converted to engineering units and then compared to predetermined engineering units that correspond to separate ranges of ambient temperatures for determining the if the refrigerant level is low.