UWE Bristol Engineering showcase 2015

Thomas Ward
MEng Mechanical Engineering
Project Supervisor
Rohitha Weerasinghe
Drivetrain Development of an Electric Formula Student Vehicle
Introduction
The project compares different types of
drivetrain used through motorsport to find an
optimal solution for an electric formula student
vehicle. The vehicle will be entered into the
2016 championships at Silverstone by the UWE
formula student team.
Formula Student
The Formula Student championship brings
together teams from across the world to
compete in dynamic and static motorsport
events. The event originated in America as the
Formula SAE championship before commencing
annually in the UK in 1998.
The teams are challenged to build a single seat
race car, and are judged on aspects of the
vehicles design and performance. Judges award
marks for vehicle cost efficiency, ingenious
engineering solutions, business presentations
and thoroughness of designs, the cars also
compete in acceleration, handling and
endurance events. It gives students the
opportunity to learn a wide variety of skills from
a real, tangible project.
The cars are of an open-wheeled ‘formula’ style,
built to meet a set of rules defined by the
Institute of Mechanical Engineers.
The teams build their cars during the academic
year, before competing in the summer each
year. New cars must be built each year, with a
new chassis at least every two years.
Going Electric
The team plan to complete with an electric
vehicle from 2016 due to how the current
ruleset is, it is possible to build an electric car
with higher performance than the petrol
powered entrants. This involves a complete
redesign including research into new motors
and drivetrain systems.
The Motors
The car will use four motors, one contained
within each wheel hub to drive the car. They
should provide the equivalent of around
100bhp, and make the car capable of reaching
100kmph in under 3.5seconds.
The team will custom make the motor casings,
shafts and cooling systems, to integrate with
the drivetrain.
The Gearbox
A reduction gearbox will also be contained
within each wheel. To create an extremely
compact and lightweight system an epicyclic
gear solution was chosen. This has been the
most complex part of the system to design,
involving creating a intricate analytical
simulation of the system to model the
dimensions and stresses.
The final CAD model of the system shown above.
It is made up of the cars upright, motor, and
epicyclic gearbox. The parts are all intended for
manufacture during the next academic year.
The gearbox was also 3D printed to check its
functionality and help describe how an epicyclic
gearbox functions.
In this arrangement the motor is connected to
the central gear and the outside turns the
wheels of the car.
Project summary
The project is to research, design and build a vehicle
drivetrain. The drivetrain is intended to be used in an
electric vehicle (EV) bespoke made by students at the
University of The West of England (UWE) for use in
the Formula Student championship. It is intended for
the university’s first electric powered entry involving
a radically different drivetrain to previous cars. The
project contains research into different drivetrain
options, and a comparison of their advantages and
disadvantages. These comparisons will help the
decision making process with respect to the choice of
design, but other factors such as the offers of
sponsorship in components may also be taken into
account. Over the course of the study the drivetrain
will be developed and optimised to suit the needs of
the vehicle. The report will go on to look more
thoroughly at a possible final design for the project.
Project Objectives
To design a drivetrain system which conforms to the
latest Formula Student rules and regulations, and
must work with the overall design of the vehicle. It
must be lightweight, and provide the best possible
performance when built within the timeframe and
budget limitations of the UWE Formula Student team.
Project Conclusion
The project has culminated in a successful design to
be used in a Class 2 entry to the formula student
championship this July (2015).
The project will continue next year in a masters
thesis, and be built for use on a car next year.