The improved fuel efficiency of new model automobiles, and
regulatory trends in recent years show that low fuel consumption
will continue to be promoted in the future. However, it is
unrealistic to believe that fuel consumption will continue to
perpetually decrease, even if hybrid vehicle systems are combined
with internal combustion engines (ICE) that run on fossil fuels.
Eventually, a "great wall" will be reached. There are two
ways of breaking through this wall and much effort is still
required by engineers before this can be accomplished.
Past papers have examined how to minimize CO₂ emissions and
target values for each technological field related to the reduction
of fuel consumption. To supplement these reports, this paper breaks
down these targets for each technological field and presents
example target engineering requirements for each part of the car
body.
Engineering requirements related to fuel efficiency for each
part of the car body are completely different from conventional
requirements. The keys for achieving the targets are achieving
so-called "efficient benefit sequences" (described below
in Sections 3.2.4 and 3.3.3) and the functional sorting method at
the body-in-white (BIW) engineering stage. An efficient benefit
sequence refers to an improvement that does not stop at its
original targeted effect, but that also produces a secondary
beneficial effect. The functional sorting method is a simple and
comprehensive way to indicate the mass efficiency of a BIW.