AER

We have sought to accurately quantify automobile HVAC air flow rates in four passenger vehicles,under a range of different ventilation settings and speeds. We used Sulphur Hexafluoride (SF6) as atracer gas, coupled with a portable doser/sampler system to quantify flow rates and leakage.Results of this work indicate a linear increase in HVAC air flow rate with increasing vehicle speed forall vehicles. Older vehicles were much less airtight than newer vehicles, a likely reflection on improveddesign and reduced door seal deterioration observed in the newer vehicles.