Design Of Triple-Shaft AMT For Torque Coupler Of Hybrid Electric Vehicles

A hybrid electric vehicle(HEV) can combine the advantages of a traditional internal combustion engine vehicle and a purely electric vehicle. HEVs have good abilities in energy saving, emissions and driving distance. Depending on the degree of hybridization and the prevailing driving conditions, HEVs can save energy up to 30%-50%.Toyota Hybrid System(THS) adopts planetary gear set as power split device. The power split device of THS is also called electronic continuously variable transmission(ECVT). Besides, most of HEVs use automatic transmission(AT), continuously variable transmission(CVT), or dual-clutch transmission(DCT) as their power coupling device to enable speed-ratio change of the engine and motor without traction interruption.Automatic mechanical transmission(AMT) has no energy-consuming torque converter and wet clutches. Compared with other kinds of transmissions, AMT has a relatively high efficiency of 92%–98%. But AMT has shift torque hole, it usually used in commercial vehicles. If the traction interruption during shifting can be compensated for by an electric motor, AMT could be a highly potential solution to reduce the energy consumption of HEVs.The main research contents of this article are as follows:Three kinds of hybrid coupling device based on AMT are proposed, working principle and gearshift process of which are introduced in detail as well as their advantages and disadvantages. The technical superiorities of Atkinson cycle engine and AC permanent magnet synchronous motor used in HEVs are analyzed. The model of gearshift actuator is established, meanwhile, the simulation results and experimental results are compared.The simulation models of HEVs using P-AMT and ECVT are built by commercial software AMESim. Fuel economy is detailed analyzed. The comparison of power performance of two kinds of HEVs is conducted using the acceleration time from 0 to 100km/h as the index. The results present that HEVs using P-AMT have more drive modes, engine starts less and has higher operation efficiency, which brings better fuel economy. Because engine and the two motors of P-AMT can drive the vehicle together, the HEVs using P-AMT has excellent power performance.The gear shift process of P-AMT is also analyzed, including time, driving torque and jerk of vehicle under pure electric drive mode and hybrid drive mode gearshift process.