Aerodynamic Analysis of Body of Passenger Bus for CO₂ Reduction and Fuel Saving

In modern society, the automotive manufacturers more concerned about how to improve the fuel economy of the vehicle for saving energy and reduce the emissions from the vehicles to protect the environment. Aerodynamic drag, which is a wind resistance force acting on the body of vehicle against the forward motion of vehicle causing higher fuel usage. The aerodynamic drag has a direct link to fuel consumption of the vehicle. This work was done with the main aim of improving the aerodynamic outer body shape of ISUZU bus, a famous bus, being manufactured and famously used in Ethiopia. CFD analysis was done on the selected bus model for estimation of the drag force. The results obtained with CFD analysis done on modified bus outer body shape were compared with the aerodynamic drag acting on the existing shape of the vehicle. The fuel consumption and the related CO₂ emissions were also estimated. Bus body models with modifications were prepared using CATIA and CFD analysis was done with Pheonix software. The selected speed range for analysis was from 80 to 120 kmph. From this work, it is observed that there is a great scope of reducing drag, fuel consumption and related CO₂ emissions by modifying the shape of Isuzu bus. When compared to model 1, model 2, at a speed of 120 kmph registered great benefits, with saving of the fuel 5.17 L/h and 52.1 tons of CO₂ emission reduction per year. The CFD results show that varying the pressure and velocity over rear and front side of vehicle got a great influence on the total drag acting on the vehicle.