Design Improvement of the Front End Shape and Headroom to Reduce Drag and Improve Stability in a Modified ISUZU Bus

Abstract

Aerodynamics is a study of the Air Force on the surface of the body when moving along the highway. Most bus that is locally modified is rectangular body shape. However body shape is one of the predetermined parameter in aerodynamic performance of bus. Drag, being one of the aerodynamic forces, greatly affects the performance of a vehicle. Reducing fuel consumption of transportation vehicle especially those who’s their aerodynamically shape is inefficient in fuel consumption such as bus important due fuel economy of one country. Because fuel economy, emission, stability, drag and others effects of poor aerodynamic design shape are the main criteria to be considered during design of vehicle body shape. Design improvement of the overall body shape increase vehicle performance. This work focused on the design improvement of frontal body shapes and headroom to reduce the drag and improve stability of locally modified ISUZU bus. Two models are designed under this study: existing bus model and modified bus model. These models are designed using CATIA software V5 R19.existing and modified bus model conduct CFD simulation with scaled down model 1:20 scale with 120km/h, 100km/h and 80km/h respectively. According to the results of numerical analysis the drag coefficient of modified bus at speed of 80km/h, 100km/h and 120km/h is improved by 27.46%, 27.24%and 26.97% respectively. The average percentage of fuel consumption reduction and lift force reduction is 16.33% and 88.5% respectively. The wind tunnel test model conduct experiment with scale of 1:35 under three speed 90km/h, 70km/h and 50km/h respectively. The experimental results show that the drag coefficient deviate by 10.9%, 9% and 7% at speed of 14m/s, 19.6m/s and 25.2m/s respectively. However according to the past study this results is optimum.