Energetics of an electric road vehicle

Abstract

This project was carried out with the primary aim of investigating the energy budget in an electric vehicle - a converted Fiat 126. For this purpose, the vehicle was instrumented to measure several transient parameters during road journeys. The work done on the data acquisition system of the vehicle consisted of modifying the original mechanical speedometer so that it will also produce a digital signal. Then, both this channel and the other channels were calibrated. A detailed calculation of the energy consumed to overcome frictional forces and air drag was carried out for both the electric vehicle and an internal combustion-engine vehicle of the same make. From this study it was shown that much less energy is consumed by the electric vehicle in this regard - the main reasons being that the electric vehicle is not subjected to engine drag, and the fact that the electric motor is much more efficient than an internal-combustion engine. The efficiency of mains and solar panel charging were calculated. And the energy loss in the motor was also investigated. Some 40 road runs were carried out. The data collected during these journeys, which consisted of the motor and controller temperature, the speed, motor voltage and current and the battery-pack voltage, were analysed. The main conclusions were that electric vehicles can be a practical form of personal transport in Malta, and electric vehicles are much more energy efficient than their internal-combustion-engined counterparts.