Title:
Going the Distance: Increasing Aerodynamic Efficiency in Electric Motorcycles with the Addition of a Rear Fairing
Abstract:
With the current industry shift to electrification, one of the largest hurdles manufacturers face in motivating widespread adoption of battery electric vehicles is achieving extended range. The longest-range electric motorcycles on the market today can cover just over 160 km during freeway cruising. Low aerodynamic efficiency, resulting from turbulent, low pressure areas created behind the rider’s torso and legs, is a significant contributor to this limited freeway range. This thesis describes the process of designing and testing an extended rear fairing which works in conjunction with the front fairing to create steady laminar flow passing over the rider and continuing along a gently tucking tail section to increase aerodynamic efficiency.
This thesis begins by outlining the current state of motorcycle design and providing background on aerodynamics and computational fluid dynamics (CFD). It then describes the process of constructing a digital model of the proposed design in computer aided design (CAD) software and testing it using CFD simulations. Results of these simulations are then analyzed focusing on the reduction in drag coefficient and on stability in cross wind scenarios. It finds that the drag coefficient of a motorcycle can be reduced by up to 0.06 through the addition of a rear fairing positioned behind the rider and partially covering the rear wheel. Additionally, this rear fairing reduces aerodynamic lift by 50% and, in crosswind scenarios, reduces the yaw torque by 7.25% but increases the roll torque by 25%.