Efficiency analysis of multi-speed automatic transmission with planetary gear trains

摘要

An approach to analyze the power flow and efficiency of multi-speed automatic transmission is proposed. The kinematic and torque equations in each shift are established based on three types of relations in hypergraphs. Load dependent/load independent power losses of each component and idle power losses caused by idle components are taken into consideration. The efficiencies of each component and the whole system are predicted by following the power flow in different shifts. The method presented is suitable for computer programming and beneficial for accurate efficiency calculation. A nine-speed automatic transmission is taken as an example to highlight the method.