Integrated Motor and Two-speed Gearbox Powertrain System Development for Electric Vehicle

A new electric powertrain system with integrated motor and two-speed gearbox is developed for pure electric vehicle in order to improve the energy efficiency and dynamic performance. The developed powertrain is composed of a double-V hybrid synchronous motor with high efficiency and power density output, a two-speed gearbox with park and shift system integrated, an 800V high voltage inverter and a transmission control unit. 2.0kw/kg system power density, 93% perk efficiency and 89% average efficiency under WLTP driving cycle are achieved. In addition, one pure electric SUV in China market is matched, and the outstanding vehicle and system integration performances are demonstrated. Two-speed gearbox enables the motor operating in higher efficiency area as often as possible, which leads to over 8% energy saving under China typical driving cycle. Thanks to the extended system speed-torque range, excellent vehicle dynamic performance for both low-speed drive away and high-speed acceleration are obtained.