Abstract
The optimization of aerodynamic drag represents an important research area for the fuel consumption reduction of heavy duty commercial vehicles. Today’s design of tractor-trailers in the European Community is significantly influenced by legislative boundary conditions regarding the overall vehicle dimensions of the entire tractor and trailer arrangement. This fact in combination with the target of high transport efficiency leads to brick-shaped vehicle outer geometries. In this way, the investigations of aerodynamic optimization at commercial vehicles are restricted to detail measures. Already performed investigations related to this topic are discussed in literature, (6), (7).
The present publication treats the aerodynamic characteristics of general modifications at the outer contour of heavy duty tractor-trailers regarding a reduction of drag resistance and thus a potential reduction of fuel consumption under steady state conditions on highway traffic. The research activities considered the European legislation for maximum vehicle dimensions and weight.
A generic, virtual three dimensional computer aided design (3D-CAD) semi-trailer truck, which displayed the characteristics of market-typical vehicles, served as a basis for several modifications. All geometrical modifications at the virtual reference vehicle were investigated and assessed by three dimensional computational fluid dynamics (3D-CFD) simulations. To get a better conclusion, the fuel consumption of each modified tractor-trailer was calculated in longitudinal vehicle dynamics simulations.
As a result of the present work, different aerodynamic optimization measures were assessed and evaluated in comparison with the reference vehicle under consideration of the transport volume. The research work demonstrates the big potential of aerodynamic optimization by application of general measures at the vehicle outer contour under compliance with the European legislative boundary conditions. As additional conclusion, the present work points out the different areas of a semi-trailer truck with respect to the potential of aerodynamic optimization. The achieved improvements can lead to a reduction of fuel consumption, which encloses both, optimized operating costs for carriers as well as reduced carbon dioxide (CO2) emissions which support the intentions to environmental friendly road transport.
KEYWORDS: commercial vehicle, aerodynamic optimization, CFD simulation, fuel consumption reduction, transport efficiency