The Effect of Aerodynamic Drag Changes on the Exhaust Emissions of a Typical Large Car

A pilot study has been conducted to determine the relationship between road vehicle aerodynamic drag and exhaust emissions on a typical Large-sized car. Various regulatory cycles, including the anticipated US06 (Bag 6) cycle, were examined in this study. The relationship was determined by varying the aerodynamic component of the road load on a 48 inch electric dynamometer and measuring the emissions on the cycle of interest. The effect of aerodynamic drag change was most notable on the US06 (Bag 6) cycle for NOx emissions where a 10% change in aerodynamic drag changed tailpipe NOx by 6% for the vehicle tested based on a linear regression.

Future NOx emission compliance, on the anticipated high load Bag 6 cycle, is expected to be challenging. There are high cost and performance degradation penalties associated with traditional NOx control measures, hence the interest in knowing what opportunities exist to change emissions thru other than conventional means.