OPTIMIZATION OF FUEL ECONOMY BY DRAG REDUCTION OF BEDFORD TRUCК

Abstract

The main concerns of automotive aerodynamics are reducing the drag. reducing wind noise and increasing the stability of vehicle to avoid the road side accidents etc. For this purpose a variety of add-on devices are available in order to improve the aerodynamics of vehicles. As all over the world the aerodynamics of tractor-trailer has been significantly improved by coupling the experimental results with computational fluid dynamics (CFD) analysis. Aerodynamically designed vehicles are the need of present era as fuel prices are at the peak. As in our country the transportation of goods is mostly through the road network as the railway network is not so effective. For transportation of goods in most areas Bedford truck is used which is not aerodynamically designed and its fuel consumption is very high. Due to non aerodynamic surfaces protruded from the main body of truck the fuel consumption is higher than the standard trucks used in Europe and America. Its structure accounts for very high pressure drag so there was a need to optimize the structure of the truck hence reducing its fuel consumption. The local body makers of Pakistan install a large wooden extension at the top of the driver's cabin to get shelter from the sunlight and for the sake of decoration. This wooden extension causes turbulence in the free stream flow that increases with the velocity and the flow separation results in the wake formation at the top and downstream of the truck. Due to wake formation at the rear end of the truck the pressure decreases at the rear and the truck experiences a net backward force. In the present study the main emphasis is given to the analysis of affects in the flow due to this wooden extension. Due to decreasing energy resources, it is vital to improve the aerodynamics of Bedford trucks in Pakistan. The effect of aerodynamic drag on performance and fuel consumption is investigated using a model of the typical Bedford truck being used in Pakistan for transportation of goods. Modifying truck geometry can reduce drag and improve fuel economy. In the present study, CFD analysis is performed. Modeling and meshing of the truck has been done on the software Gambit and Gridgen. By removing the wooden extension of the truck the drag co-efficient reduces by approximately 30 percent and the fuel consumption is significantly improved.