The Aerodynamic development of a Compact SUV for FE improvement and compliance with CAFE norms

The Mahindra 3XO is a compact SUV, the first-generation was introduced by Mahindra in 2018. This paper explores some of the challenges entailed in developing the next generation of this successful product, maintaining exterior design cues while at the same time improving its aerodynamic efficiency. A development approach is outlined that made use of both CFD simulation and Coastdown testing at MSPT (Mahindra SUV proving track). Drag coefficient improvement of 40 counts (1 count = 0.001 Cd) can be obtained for the best vehicle exterior configuration by paying particular attention to: • AGS development to limit the drag due to cooling airflow • Front wheel deflector optimization • Mid underbody cover development (beside the LH & RH side skirting) • Wheel Rim optimization • Rear wake control strategy In this paper we have analysed the impact of these design changes on the aerodynamic flow field, Pressure plots and consequently drag development over the vehicle length is highlighted. An interaction between grill closing and underfloor design of the same nominal dimensions is explored. Customers are increasingly demanding compact hatchback-like fuel consumption and CO2 emission limits are being made more stringent with upcoming revised CAFE norms. Therefore, it is essential to increase the efficiency of the vehicle and to minimize all energy losses. Aerodynamic drag constitutes ~30% of total energy consumption on WLTC cycle which is very significant. Compared to improvements in power train and vehicle mass, reduction of aerodynamic drag can be achieved at relatively low cost. For this vehicle, we demonstrate ways to improve the aero drag coefficient, 10% lower than the first-generation of XUV 3OO, thereby delivering 2-3% Fuel Economy benefit to the customers.