Fuel Economy of Hybrid Electric Heavy-Duty Vehicles

Abstract

Fuel economy of parallel and series hybrid-electric heavy-duty vehicles was analyzed by a combined analytical and simulation approach. The combined approach enables an evaluation of energy flows and energy losses on different energy paths and provides their impact on the fuel economy. The paper quantifies influences of different hybrid-electric vehicle (HEV) topologies, power ratios and characteristics of the components, and applied control strategies on the fuel economy of HEVs. Moreover, the impact of powertrain hybridization on the fuel economy is also analyzed for vehicles carrying different loads operating according to different drive cycles. It is discernable from the results that all of the above parameters significantly influence fuel economy of HEVs. Based on the innovative combined approach the paper reveals and analyzes mechanisms that lead to an optimized fuel economy of hybrid-electric heavy-duty vehicles. Valuable and generally valid guidelines for improving the fuel economy of HEVs are also given.