ABSTRACT
In this
paper, the
performance and overall efficiency optimization process for a full-electric
Formula Student car are reported. The Formula Student Electric is a
scientific-educational competition of high technological value that requires
the development and construction of a fully electric open-wheel prototype car;
the cars rival both in terms of absolute performance and in terms of total
energy efficiency, especially in the most important test, the endurance event. The
optimization of the performance and efficiency of the cars affects various
aspects of both the powertrain and the car body and, as macro areas, three
crucial themes can be identified for the development of the cars: the power
maps with which the inverter manages the electric motor, the aerodynamic kit
installed onboard and the overall weight of the car. In this regard, in fact,
it is not obvious, for example, that it is convenient to use the maximum power
allowed by the rules for the powertrain (80 kW); in the same way, it is not
inevitable that it is advantageous to install all the components of the
aerodynamic kit (front wing, rear wing and undertray with diffusers) and,
finally, the best configuration may not be the one with the lightest car. This
is also in consideration of the fact that some choices must necessarily be a
compromise, such as completeness of the aerodynamic kit and vehicle weight.
Hence the search for an optimum point is necessary. The work proposed here aims
to describe the experimental search for the optimal configuration for the car
of the Sapienza Fast Charge team. To achieve the goal, the analysis has been
conducted with several experimental tests on a simple test ring with a dynamic
configuration comparable to that of a typical endurance track. The tests have
been fulfilled with different combinations of aero-kit configurations, with the
aero devices available on the car, rear wing, front wing and undertray, and
with different energy management strategies, implemented in the power map of
the inverter. The best result has been achieved considering the official
ranking calculation of the Formula Student rules 2020, with a combination of
best track time and lower energy consumption. The work described here will
start with the description of the prototype vehicle, reporting the details of
the powertrain and storage system installed onboard. Then, the aerodynamic
devices designed and built will be described, and the CFD analysis of their
performances will also be reported. In the following, the description of the
test track will be discussed and a comparison of a typical track of an
Endurance test in Formula Student will be fulfilled. Finally, the parameters
measured experimentally will be described and all the tests carried out will be
discussed, in order to determine the optimal configuration of the car.