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. Twospeed 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.