Energy Consumption Analysis of a Novel Two-speed e-Powertrain System for Electric Vehicle

A novel electric powertrain system with integrated motor and two-speed gearbox is developed for a pure electric and all-wheel-drive SUV (Sport Utility Vehicle) to balance the energy consumption and drive quality. The e-powertrain layout of this all-wheel-drive SUV is investigated, a traditional single-speed gearbox is selected for FDM (Front Drive Module) and a novel two-speed gearbox is adopted for RDM (Rear Drive Module). A series of verification tests are performed and the efficiency data and drag loss under different working conditions are generated through the efficiency bench test follow China GB standards. The all-wheel-drive vehicle and e-powertrain models are created based on calculation software, then the energy consumption in WLTP cycle, WOT (Wide Open Throttle) performance of the two-speed gearbox are analyzed. It finds that the RDM with two-speed e-powertrain system will bring 3.64% energy reduction thanks to extending the motor working opportunity in higher efficiency area, 3.99% energy reduction thanks to the neutral gear function to reduce the energy loss during the cruise and coast-down running conditions, totally 7.63% energy saving in WLTP cycle is achieved. Meanwhile, the dynamic performances maintain in a competitive level.