Fuel Economy of Series Hybrid Electric Bus by Matching the Gear Ratio of Different Capacity Traction Motors

This paper investigated the different gear ratio matching effect on the series hybrid electric bus especially for the 90 kW & 150kW traction motors on the fuel economy. The 90 kW & 150 kW traction motors make the system use more efficient operating points; thus, the system is more efficient than when the 240 kW single unit is used. Furthermore, matching the different gear ratios allows the nonlinear characteristics in the traction motor efficiency to be used more efficiently; thus the standard for how to select the gear ratios was proposed. The fuel economy selection was optimized by the hybrid optimization methodology using RSM and the univariate search method, both of which are well known for their straightforward concepts and adequate performances; thus, the new suggested matching theory noticeably improved the system efficiency. The work presented here has profound implications for future studies for the design of the hybrid electric vehicle, as well as the plug-in hybrid and the electric vehicles and was carried out on the AMEsim-Simulink Co-simulation platform.