Analysis of Regenerative Braking Effect to Improve Fuel Economy for E-REV Bus Based on Simulation

Emission regulations are strict globally and oil price goes up continuously. There are many researches for eco-friendly vehicle to solve these problems. Among them, extended-range electric vehicle (E-REV) utilizes electric energy directly and can drive extended range by generating additional energy. It has characteristics of both an electric vehicle (EV) and hybrid electric vehicle (HEV). According to state of charge (SOC) for battery, E-REV can drive either EV mode or HEV mode. In this study, effect of regenerative braking is analysed to improve fuel economy for the E-REV bus when vehicle drives as EV mode. In advance, sizing of components is conducted to develop forward simulator for calculating fuel economy. The forward simulator is developed using Matlab/Simulink. Considering performance for battery, limited regenerative braking is applied in the forward simulator and the effect of regenerative braking is analysed when driving cycles are determined. And then effect of coast driving is analysed by comparing to constant speed driving. Effect of regenerative braking when vehicle is coasting is verified and this result can be utilized to develop control logic for regenerative braking in further research.