Influence of Transmission Layout
Apart from the road resistance parameters and the engine characteristics of the vehicle which are characterized by the form and position of the full-load curve in the engine map, the layout or the control strategy of the transmission has an enormous influence on driving performance.
The required maximum speed vmax generally determines the smallest ratio of the entire drive train (ient = iG·ir(f)). If a stepped transmission with a direct final gear (iG = 1) should be used, the axle ratio has to be adjusted in such a way that the required maximum speed can be reached over the entire ratio. This on the other hand, has an influence on the ratios of the remaining transmission levels (see Chapter 2.4 in the script). If, however, the drive axle ratio (ir(f)) is prescribed, the required maximum speed determines the smallest transmission ratio.
The maximum speed is achieved, if the power supply and the power demand are at equilibrium. Three possible layouts are then available:
Layout on vmax,theor,
Overspeeding layout,
Underspeeding layout.