Optimal sizing of the EVT for a hybrid urban delivery truck⁎

The objective of this paper is to find the trade-off solutions among fuel economy and machines sizes for a hybrid urban delivery truck with an electric variable transmission (EVT). To solve the optimization problem, exhaustive search is conducted over the feasible EVT set obtained by different drivability performances. Proper design parameters for each machine of the EVT are selected and defined. Dynamic programming (DP) is used to benchmark the fuel economy. To overcome the drawback of huge computation burden of the optimization process caused by DP searching, a bi-level DP method is formulated. Simulation results show that EVT truck could lead to 21% reduction of fuel consumption compared to a conventional truck. Finally, the Pareto front of the optimal sizing problem is presented.