Analysis of Gearbox Losses for High-Performance Electric Motorcycle Applications

Finding an architectural solution that satisfies electric motorcycles’ performance and riding range is challenging due to the electric powertrain constraints, such as low battery energy density. This paper analyzes the gearbox and powertrain efficiency for battery electric motorcycles (BEMs) based on the drivetrain architecture and under various vehicle use scenarios. The impact on the consumption of a constant-speed gearbox is investigated, focusing mainly on load-independent losses. The analysis is performed using an analytic approach and experimental data. Two different gearbox and powertrain solutions are characterized through test bench experiments, running them under free-driving conditions and no-load tests. A comparison of these powertrain solutions in terms of consumption for the same motorcycle model under different speed profiles (WMTC, LA-4) is conducted. The results show the energy losses and provide information for defining drivetrain components and architectures.