Abstract
The TU/e has developed a battery electric vehicle called the Lupo EL using a VW Lupo 3L as donor platform. This vehicle is used as a research platform now. An accurate vehicle energy usage model is really important to improve the energy efficiency and to build a range estimator. This paper will analyse the vehicle energy consumption from the power socket to wheels by analysing the measurement results and then building an accurate vehicle energy usage model to calculate the energy consumption for different driving conditions. The vehicle energy usage model is built in a reversed order, the vehicle speed is the input and the energy required from the power socket is the output. To determine the energy consumption, the energy flow can be divided into four parts: the battery part, the electric motor part, the mechanical part and the auxiliary power part. The auxiliary power can be measured when the vehicle is standing still. The aerodynamic drag force and rolling resistance can be determined in a coast down test. The motor power losses are analysed by constant speed driving, and after that a motor efficiency map is built based on the measurements. The battery is modelled by an electrically equivalent circuit model to calculate the energy losses. The model can estimate the energy usage of the Lupo EL under different circumstances with an accuracy of 95%.
KEYWORDS – BEV, powertrain, battery, modelling, energy consumption