UK ELECTRIC VEHICLE RANGE TESTING AND EFFICIENCY MAPS

Cenex, the UK's centre of excellence for low carbon and fuel cell technologies, is currently deploying electric passenger cars and vans throughout the UK in a series of Government funded low carbon vehicle trials. This study, produced in partnership with Millbrook Proving Ground, investigates comments and concludes on energy consumption in electric vehicles with varying driving styles and driving duties. At Millbrook, the electric vehicle (EV) track cycle is designed to represent real world driving duties over city, rural, hill and high speed circuits. It is shown that the drive efficiencies over the EV track cycle vary significantly by driver and the largest variations are noted on tracks with the highest opportunities for regenerative energy capture. To further study the regenerative energy, a model is developed and the percentage of potential vehicle energy recovered during deceleration is quantified. This model is also used for assessing the efficiency of input energy used to propel the EVs over the EV track cycle, where a diesel vehicle is also tested over the same circuits to allow a baseline for the data. The track results are contrasted with energy consumption data from real world vehicle trials. Comparison is drawn on interactions with drive efficiency and regeneration performance observed under real world conditions with that achieved during track testing. The study completes with an analysis on the effect of range anxiety quantifying the State of Charge (SoC) where users appear reluctant to start an electric journey and the effect SoC has on drive efficiency demonstrating how users modify their driving style to conserve energy when SoC reduces.