Experimental analysis and quantification of air infiltration into a passenger car cabin

•Infiltration introduces non-filtered air directly from the outside into the cabin.•Infiltration path is located at the front of the cabin on a modern electric vehicle.•A tracer gas method with CO2 is used to estimate the infiltration flow rate.•The flow rate can reach levels as high as 117.5 kg/h at high vehicle speed.•The blower and recirculation flap can be managed to reduce infiltration. Nowadays, air quality in closed environments is of major interest, particularly in very small volumes such as car cabins. In typical driving conditions, ambient air enters by infiltration as the vehicle speed increases. In order to satisfy more ambitious requirements on air quality and energy savings, it is necessary to evaluate the infiltration risk. At first, an experimental method is created to identify the infiltration path in the cabin of a moving car. On a modern electric vehicle, the privileged path is observed at the front of the cabin near the feet of the front passengers. A second experimental campaign is performed to quantify the infiltration flow rate. Results show that the flow rate is not negligible as it can reach several dozen kilograms per hour. The ventilation settings (blower speed and recirculation ratio) can be managed to reduce or even completely remove infiltration in some cases.