Effect of Streamlined Design of High-speed Coach on Fuel Economy and Emission

The most important aerodynamic design concept of an automobile body shape is on fuel savings with the reduction of harmful emission, driving stability and aerodynamic noise and vibration. From the previous studies [1]similar to[3], it was found that fuel savings and emission reduction has more important meanings on the aerodynamic design of heavy-duty vehicles such as buses and trucks but the driving stability and aerodynamic noise problems for the small-size sadan. In this study, a streamlined design concept is applied to the front side of a long-distance highspeed model bus to see its effect on reducing the aerodynamic pressure drag and to a rear spoiler to understand its effect in reducing the induced drag at the rear flow field of the model bus. Computational fluid dynamics (CFD) simulation scheme was incorporated to analyze the variation of aerodynamic effect on the model buses with the change of body configuration. From the study, it was found that the total drag of the conventional high-speed model coach(FX212) was reduced by 27.4% at a speed of 120km/h by applying the streamline-designed body shape, which is equivalent to 17.3 kW in the engine brake power. The resulting fuel saving effects are a reduction in fuel consumption of about 17,045 liters and a reduction in CO2 emissions of 48.1 tons per year by each bus at the given operating condition.