Transportation sector in India accounts for 12% of total energy consumption. Demand of energy consumption is being met by the imported crude oil, which makes transportation sector more vulnerable to fluctuating international crude oil prices. India is mindful of its commitment in 2016 Paris climate agreement to reduce GHG emissions intensity of its GDP by 40% by 2030 as compared to 2005 levels. To fast track the decarbonization of transportation sector, commercial vehicle manufacturers have been exploring other viable options such as battery electric vehicles (BEVs) as a part of their fleet. As on today, BEV has its own challenges such as range anxiety & high total cost of ownership. Range anxiety can be certainly addressed by optimum sizing of electric powertrain, reduction in specific energy consumption (SEC) & use of effective regeneration strategies. Higher SEC can be more effectively addressed by doing vehicle energy audit thereby estimating the energy losses occurring at each powertrain component of an electric vehicle.
The work illustrated in this paper involves drive cycle-based energy audit & range estimation for 4X2 rigid electric truck using simulation approach. It involves strenuous exercise of simulation specific input data generation by doing rigorous component level tests for battery, motor, tires & auxiliaries. Duty cycle data was acquired for 3000 km & condensed cycle of 32 minutes was formed which represents real world usage pattern. Data recorded in component and vehicle tests was used to build robust simulation model in GT-DRIVE. Simulated SEC was validated within 4% with on road trails. 73.5% of battery discharge energy was used to overcome rolling resistance loss, aerodynamic drag loss, electromechanical conversion loss, auxiliary losses, braking losses & differential losses. Effective power at wheels observed to be 26.5% of total battery discharge energy. Sensitivity analysis for RAR, RRC, coasting & braking regeneration limits was carried out and effect of each parameter on final SEC was studied and optimum set of parameter combination was suggested to the OEM. Outcome of this project has also laid down the sophisticated methodology to carry out energy audit of any electric vehicle, which in turn will help to bring simulation predictions much closer to the real-world scenarios.