Abstract
Air drag has been acknowledged to have a significant importance in energy use of a heavy truck. However, the construction of the vehicles has not traditionally been very streamlined and has focused first and foremost on maximizing the available cargo space. Even though aerodynamics has been considered in the design of new tractors, the combination of a truck and a trailer does not fulfil the requirements of low aerodynamic drag. The heavy vehicles have not changed considerably, even if the effect of aerodynamics is common knowledge. Optimising the cargo space, limited measurement, availability and extra costs of spoilers and other aerodynamic components are reasons for this conservativeness.
With its aerodynamic demonstration vehicle VTT implemented aerodynamically beneficial solutions to con-temporary truck and trailer construction used in Finland and Sweden to demonstrate the potential of drag reduction on fuel consumption while operating mostly within the limits of current legislation for maximum dimensions of the vehicle combinations.
Different configurations of advanced aerodynamic truck and trailer designs were initially studied with wind tunnel testing using scale models. The scale model testing doesn’t represent actual performance of a full scaled vehicle, but provides valuable information about the quantity of possible improvements.
To demonstrate the actual effect of the add-on aerodynamic improvements, the full-size truck-trailer combi-nation was tested on-road using coast-down methodology of VTT with road topology and wind speed correc-tions. The results of these coast-down measurements were used to determine the road load models for chassis dynamometer measurements. Finally the energy consumption of the demonstration vehicle with different add-on kits was measured on chassis dynamometer in laboratory environment.
KEYWORDS – Aerodynamics, Heavy duty, Demonstration, Concept, On-road