ABSTRACT
This project entails the design construction and test evaluation of an energy efficient go-cart engine and transmission system.
A
target of 100km/l of fuel is set, having the knowledge that weight
plays a major role in the efficiency of any vehicle using internal
combustion engines; and also the aerodynamics of the vehicle body design
is equally important as well. Aluminium profiles are used to construct
and fabricate the chassis while wooden board is used for floor covering.
Care is taken to reduce any excessive weights by cutting off parts that
do not contribute to the structural integrity of the vehicle or which
its contribution is highly negligible.
A CRF70 series engine was
selected for the design with a net torque of 7.1Nm, with the required
torque compensated for using a gear ratio of 1:3. The vehicle design
acquiesces with the Shell Eco-Marathon Global Rules for the prototype
gasoline category; which implies that there are design requirements and
rules which must be met and not to be exceeded. For instance, a need for
idling when the engine is cranked. The engine is installed behind the
bulkhead separating the driver compartment from the engine compartment
and rubber dampers of known damping coefficient are used to check the
effect of vibration of the engine. A fuel tank of 250ml is used as
reservoir for the gasoline while a chain drive mechanism is used to
transmit power from the engine to the rear-wheel shaft on which the rear
wheel is mounted; this in turn moves the entire vehicle. Care is taken
to ensure fine tuning of the carburettor to avoid so much fuel
consumption. After series of testing, the vehicle participated in the
just concluded 2016 Shell Eco Marathon Challenger event held in South
Africa which is one of the most genuine student engineers’ competition
in the world where students in universities all over the world are
challenged to design, fabricate and drive the ultimate energy efficient
vehicles.
A result of 52.54km/l of fuel was recorded at the event
computed using standard international algorithms as against 48km/l which
was estimated. This implies acceleration, temperature of fuel and
aerodynamic drag are all factors that contribute to the efficiency of
any vehicle. This result of 52.52km/l is about 52.54% of the set target.