Optimal shift decision of automated manual transmission for hybrid electric transit bus

Most HEBs with AMT adopt the traditional single or two parameter shift schedule, however, HEB is very different from traditional bus, this approach cannot make full use of the advantage of hybrid. In order to obtain the optimal fuel economy, emission and low shift frequency, an objective functional is established for hybrid electric bus based on simplified models of hybrid system, and a new solving algorithm based on dynamic programming (DP) is also presented. In the end, the best shift decision points in Chinese typical urban transit bus driving-cycle are obtained. After comparison between the traditional two parameter shift schedule and the shift decision based on DP, it's proved that the best shift decision points can improve the fuel economy of the HEB obviously through simulation and road test under Chinese typical urban transit bus driving-cycle, and the number of gear shift is also obviously reduced.