Design of an Energy-Saving Driving Strategy for Electric Buses

In recent years, fully electric vehicles (EVs) have accounted for a higher proportion of urban buses. On account of their relatively short cruising range, many technologies were used to improve the driving range, such as improving energy management strategies and promoting the performance of the battery and engine. The purpose of this study was to develop an energy-efficient driving strategy to save energy. The strategy consists of two parts: determining a velocity interval for lower energy and establishing an energy-saving acceleration mode. First, 30 velocity datasets were collected from an actual bus line. An electric bus model and energy consumption equation were established in the AVL CRUISE software to analyze the energy consumption. Next, the velocity interval was determined based on the actual data with the objective of maximizing engine efficiency and minimizing energy consumption. By considering uniform motion and traffic conditions, 30-40 km/h was determined as the velocity interval of lower energy for the electric bus mentioned in this paper. The acceleration characteristic parameter beta represents the curve of velocity versus time in different acceleration processes, which was chosen to describe the acceleration mode; we found that when beta is greater than 0.2, the lower the beta value, the lower the energy consumption per kilometer was. Finally, the energy-saving driving strategy was verified by conducting a simulation. It was determined that the reduction in energy consumption per kilometer after implementing the energy-saving driving strategy was between 12.32% and 18.7% for short sections of acceleration and 2.47% for the entire bus trip.