Configuration Design and Energy Balancing of Compact-Hybrid Powertrains

The development of compact and efficient hybrid electric vehicle powertrains for low initial and on-going costs requires consideration of numerous, often competing factors. Appropriately designing and sizing these powertrains requires the consideration of requirements for vehicle range and performance, considered directly through the sizing of motors and engines, and indirectly through minimization of vehicle mass whilst being constrained by total stored energy in the vehicle, against the impact on vehicle emissions and on purchase and ongoing operational costs. In addition to these considerations the actual driver use will strongly influence the energy consumed and vehicle emissions. It therefore becomes beneficial to provide flexibility in hybrid vehicle configuration design to enable the minimization of vehicle emissions and ongoing vehicle costs. The purpose of this paper is to study the various alternative vehicle powertrain configurations for application to small scale hybridization demands, such as scooters or motorcycles. Powertrain configurations studied in this paper include plug-in hybrid electric (PHEV), battery hybrid electric (BHEV), and a pure electric vehicle (PEV). To design and size each of the configurations a statistical approach is taken, power and load demands are studied and utilized to size powertrain components. Results are extended to size vehicle energy storage for electric only range of 25, 50 and 100 km, and total vehicle range of 100 km for the BHEV and 200 km for the PHEV. Based on the results developed from the analysis mathematical models of each of the powertrain configurations are then developed in Matlab/Simulink and numerical studies of vehicle energy consumption in comparison to range are conducted. Outcomes of these simulations are compared to an operating cost based analysis of the suggested powertrains; the benefits and limitations of each design are considered in detail.