Modeling of Hybrid Electric Vehicle Powertrains - Factors That Impact Accuracy of CO₂ Emissions 2019-01-0080
Modelling is widely used for development of hybrid electric vehicle (HEV) powertrain technologies, since it can provide a relatively accurate prediction of CO₂ emissions, for a fraction of the cost and time of actual tests. Still, depending on the detail of the model and the simulation platform, the results can have a significant deviation compared to actual tests. When it comes down to the comparison of different technologies or powertrain parameters, the results should be accurate enough relative to each other, since both powertrains are tested with similar model detail and simulation parameters. However, when CO₂ emissions of a vehicle model are simulated under a driving cycle, significant deviance in results might occur, compromising simulations.
Therefore, this paper investigates the effects of certain modelling and simulation parameters on CO₂ emission results, for a HEV under three driving cycles in GT-Suite platform (NEDC, WLTC and RTS95 to simulate real driving emissions (RDE)). Battery state of charge levels, control systems, component data resolutions, warm-up phase, time-step, driver controller behavior and other simulation parameters have been investigated and their effect on CO₂ emission results are studied. While each of these parameters result in either a lower or higher CO₂ value, depending on the reference point, a difference of +-15% is still possible. Unfortunately, a lot of papers on HEV powertrain modelling do not include and/or overlook the level of detail regarding these parameters. By identifying key parameters and quantifying the effect of their simplification, this paper aims to help improve the accuracy of HEV powertrain simulations, providing more reliable results.
Sarp Mamikoglu, Petter Dahlander
Chalmers University of Technology
International Powertrains, Fuels & Lubricants Meeting