Abstract
Keywords - Aerodynamics, Engine Cooling, Cabin Climate Control, Soiling, Aeroacoustics
The development of the aerodynamics of the new TGX and TGS ranges was closely linked into elaboration of their design. The latest development tools were employed with the goal of reducing the drag. Depending on the development phase the vehicle had reached, computer simulation (CFD), measurements in the 1:4 model wind tunnel or measurements in the 1:1 vehicle wind tunnel were used.
In the development of the new ranges MAN had already carried out examinations of the aeroacoustics in the concept phase. This was made possible by the wall array method used in the model wind tunnel. With this method the aeroacoustic noise sources can be located from outside and selectively optimised. However, the measurements using the artificial head in the 1:1 wind tunnel with the full semi trailer train are still the most important development tool.
To satisfy the high demands imposed by the Euro 4 and Euro 5 exhaust-gas standards on the engine cooling system, a detailed calculation model of the TGX and TGS with driveline was built up as early as in the design phase. Thanks to the information gained from this it was possible to optimise the topography of the airflow through the engine compartment to such an extent that the effective volume flow rate of the cooling air was increased by 15 % from the level of the TGA without any negative effect on the drag.
CFD calculations were used for targeted optimisation of components of the heating and airconditioning system too.
With the aid of visualisation of the airflow the ducts and the outlet openings in the heater ducts were designed so that their flow topography was as pleasant as possible for the driver and co-driver.
Another major task in this area, and one which also leads to higher driving safety, is de-icing of the windscreen and side windows. This was improved by reducing the flow losses by 20 % and by means of a coordinated outflow pattern.