Yue, H., Lu, X., Li, X., Gao, B. et al., "Performance Analysis of Multi-Speed Torque Coupler for Hybrid Electric Vehicle," SAE Technical Paper 2016-01-1149, 2016, doi:10.4271/2016-01-1149.
A novel torque-coupling architecture for hybrid electric vehicles is proposed. The torque-coupling device is based on automated manual transmission (AMT), which is highly efficient and provides six gears for the engine and three gears for each motor to enable the engine and the motors to work at high-efficiency levels in most cases. The proposed power-shift AMT (P-AMT) does not have a hydraulic torque converter and wet clutches, which dampen the driveline shock. Thus, the drivability control of the P-AMT becomes a challenging issue. Accurate engine, motor model and transmission model have been built and the dynamic control of the gear shift process of PAMT in hybrid mode is simulated. The electric motors compensate for the traction loss during the gear shift of the engine. Thus, the engine is allowed to adjust its speed actively by controlling the throttle opening θth and spark advance Δθsp to reach the target synchronous speed in a relatively long time, thereby eliminating the use of a clutch. The simulation results show the P-AMT has good performance in fuel economy and gear-shifting quality.