The success of the detailed approach, affording the study of
a transmissionbyananalytical point of view,is relatively recent
and strictly related to the use of computers and software. Only
by using this approach it is possible (1) to easily manage the
many equations written for each component and also (2) to
directly relate the mathematical model to reality by creating
functional maps. In these maps, each element involved in the
power flowengine-ground, or in the control of the flow itself, is
represented as a block interacting with the others in the system
(in series or in parallel) and exchanging scalar/vector quantities
and signals (activation/deactivation, selection). Each terminal
block (i.e., without any other block inside) is mathematically
associated with one or more functions, linking inputs to
outputs and having an analytical-theoretical origin (mathematically
derived equations) or an experimental derivation (i.e.
regressions based on data). In the simplest energetic description
of a generic subsystem, each block is assigned a unique
value representing its efficiency under all operating conditions
(assumedtobeconstant). Forexample, Galvagno, Velardocchia,
andVigliani (2009),Mantriota (2002),MangialardiandMantriota
(1999) calculated the overall TE on the basis of individual subsystems’
TEs and by observing their layouts: they created
a zero-dimensional model in which the individual coefficients
were properly added or multiplied together.