Impact of Vehicle add-ons on Energy Consumption and Greenhouse Gas Emissions

The primary objective of this study is to determine the impact of vehicle add-ons on energy consumption and greenhouse gas emissions (mainly CO2) for commonly used fossil fuels in passenger car. Various commonly used vehicle add-ons (police siren, advertising sign, taxi sign and roof rack) and roof load (e.g., ladder and barrel) produce additional aerodynamic drag. To measure the aerodynamic drag produced by these add-ons a wind tunnel study was undertaken using a replica reduced scale model passenger car. The aerodynamic drag for different add-on configurations were measured for a range of vehicle operating speeds and yaw angles. The results show that the vehicle add-ons have notable impact on aerodynamic drag as they can generate 5% to 40% more aerodynamic drag depending on cross wind effects. The taxi sign has minimum impact and the advertising sign has highest impact on aerodynamic drag. Also roof load such as ladder and barrel can significantly increase the drag. The aerodynamic drag was related to a range of commonly used fuels e.g., petrol, diesel, compressed natural gas (CNG) and liquefying petroleum gas (LPG) consumption, and their relative CO2 gas emissions. The results indicate that for a given range, the emission of CO2 is the highest for the CNG due to its lowest energy density.