Operating air conditioning unit for vehicle - heating vaporiser at low temperatures to prevent icing

摘要

The air conditioning unit has a temp. monitor for the input air to the vaporiser. When this falls below 4 deg. C. a heating control is applied to prevent icing of the vaporiser. An electric heating element in the vaporiser can be activatd, or a set proportion of recirculated air is added to the fresh air inlet to hold the air-flow over the vaporiser above a set level. The system includes an oxygen sensor for the interior of the vehicle, or a carbon dioxide sensor or similar to ensure that the interior air remains at comfortable levels. The vaporiser can also be heated via heat exchangers from the air conditioning system. ADVANTAGE - Improved effectiveness at low exterior temperatures