System-level simulations of the effects of driving cycles and driver behavior on the energy flow in a battery electric vehicle

Abstract

Fully-electric car technology has made enormous progress in recent years. With driving range as one of the key factors for commercial success and the vast variety of real-world driving behaviour, the question arises how different levels of driving aggressiveness and drive cycles influence the energy flow in a Battery Electric Vehicle (BEV). Vehicle-level simulations in Siemens Simcenter Amesim were carried out to assess the energy flow in the BEV. Both standard drive cycles and real-world drive patterns represented city, rural and highway driving were considered. The driving aggressiveness was modelled by considering velocity modified and acceleration modified drive patterns separately. The simulation results show that drive cycles with high RPA and relatively low average velocity (20-30 km/h) have the lowest energy consumption due to the ability of BEVs to recuperate energy from regenerative braking and their high average efficiency at these velocities. Thus, BEVs are more sensitive to changes in velocities than in accelerations. High accelerations not only increase the inertia work share of the drive cycle, but also the amount of energy recuperated by regenerative braking. Higher velocities, however, only increase the road work part of wheel work leading to increase in energy demand without the possibility to recover it through regenerative braking. Although questions such as the exact impact of road slopes on energy consumption remain open to further investigation, it can be stated that BEVs are particularly suitable for city traffic with its frequent braking events and relatively low average velocities.