Study of Long-Term Variation of Air Resistance of a Tractor with Semitrailer Using Recorded Weather Data Together with Vehicle Data

<div>With air resistance being one of the two major energy losses in on-road vehicles (the other one being tire losses) and therefore heavily contributing to the range of battery electric and fuel cell electric vehicles, it is necessary to account for realistic air resistance in a priori assessments like vehicle range estimations, component dimensioning, and system simulations.</div> <div>However, lack of input data tempts analysts to instead assume unrealistic “nominal conditions” throughout—a simplification which usually underestimates the amount of energy actually required to overcome air resistance and completely ignores the fact that varying environmental conditions will lead to significant variances in energy consumption and therefore vehicle range. Using “nominal conditions,” it is thus impossible to assess the robustness of these measures and, therefore, difficult to design robust systems and to perform meaningful trade-off studies.</div> <div>In this study, we show how publicly available data from weather observations can be used to assess the long-term variation of air resistance of a truck with a semitrailer. Realistic distributions of energy losses due to air resistance, covering multiple years, are derived—showing not only average values but the complete envelope in which the energy losses vary.</div> <div>This, in turn, enables to follow up with probabilistic calculations of vehicle performance in order to assess robustness and trade-offs on various system levels of interest. As a consequence, consumption and range predictions of EVs and ICE vehicles can be performed with higher accuracy and confidence.</div>