Optimization of AMT Gear Shift Strategy for Pure Electric Bus Based on a Fixed City-Bus Route

Currently, the electric vehicles equipped with an automated mechanical transmission (AMT) are usually employed with the conventional two-parameter gear shift schedule to improve the dynamic and economic performance, especially for the pure electric bus (PEB). However, the conventional gear shift strategy cannot take full advantage of the electrical drivetrain of the PEB. Although the Dynamic Programming (DP) can acquire an optimal gear shift strategy during the whole driving profile, it requires abundant previous knowledge of the whole driving cycle. In this paper, an optimized method of gear shift schedule for the PEB based on a fixed city-bus route is proposed, for which the DP algorithm is employed for three different periods of historical driving conditions to obtain the optimal shift points. And then fitting by the orthogonal least squares polynomial, an optimized gear shift strategy of the PEB based on the city-bus route can be obtained and extracted for an actual application. After a verification of the optimized gear shift schedule by a stochastic driving cycle, the proposed gear shift schedule can be excellently improved than the conventional strategy, but no prominent than DP, compared with the gear shift schedule of the conventional and DP algorithm. However, it can be more easily acquired.