Evaluation and selection of accumulator size in electric-hydraulic hybrid (EH2) powertrain

Abstract

An electric-hydraulic hybrid (EH2) powertrain has shown significant potential in extending driving range and reducing battery discharge current stress. Research has shown that the size of the hydraulic accumulator can have substantial influence on the performance and even the design of components in the overall electrified powertrain of the vehicle. This paper evaluates three sizes of hydraulic accumulator for urban delivery trucks according to different degrees of hybridization in the electric hydraulic hybrid powertrain. It has been shown that different hydraulic accumulators have notable impact on the reduction of battery current stress and electricity consumption, optimal utilization of hydraulic energy storage system, weight, cost, and hydraulic component efficiency.