An experimental method for evaluating vehicle cabin airtightness and ventilation performance

Abstract

An experimental method is proposed for evaluating the airtightness of a vehicle cabin and the ventilation effects of three components of the vehicle ventilation system. The measurement results are used to derive a theoretical equation to predict the total air infiltration rate of the cabin as a function of the pressure difference between the cabin interior and exterior, respectively. The validity of the predictive equation is demonstrated by means of fan pressurization experiments performed with the vehicle air-conditioning system set in the fresh air mode. It is shown that the prediction results for the total ventilation rate deviate from the experimental results by less than 10%. The infiltration ventilation effect of natural diffusion in the vehicle cabin is measured using the CO2 tracer gas method. The air exchange rate (ACH) of the cabin is found to be 0.816 in the recirculation air mode and 3.554 in the fresh air mode.