Experimental Investigation of the Energy Efficiency of an Electric Vehicle in Different Driving Conditions

Energy efficiency of electric vehicles (EVs) and the representativeness of different driving cycles are important aspects to address EVs performance in real-world driving conditions. This paper presents the results of an explorative tests campaign carried out at the Joint Research Centre of the European Commission to investigate the impact of different driving cycles on the energy consumption of an electric vehicle available on the market. The vehicle is a battery electric city-car which has been tested over the New European Driving Cycle (NEDC), the current version of the World-wide harmonized Light vehicles Test Cycle (WLTC) and the World-wide Motorcycle emission Test Cycle (WMTC). The tests are performed at different ambient temperatures (namely +23 °C and −7 °C) with and without the use of the Heating Ventilation and Air-Conditioning (HVAC) system (in cooling and heating mode, respectively). The NEDC test was chosen being the driving cycle prescribed by the legislative type-approval procedure, while the WMTC and WLTC were chosen to investigate the energy demand of substantially different driving cycles, characterized by higher accelerations and a longer high speed phase duration. To further investigate the impact of the HVAC system on the energy consumption also some preliminary tests on the Mobile Air Conditioning (MAC) test procedure are presented.

The results of these tests are compared with the fuel consumption and gaseous emissions results of one hybrid vehicle and three conventional fuel passenger cars (all Euro 5a certified vehicles, tested on the NEDC cycle). The results constitute the basis for future technical analysis and considerations to determine the representativeness of legislative test-procedures.