Abstract:
The problem of unavailability of conventional fuels and pollution is becoming a serious issue
day by day. Many countries have been looking for alternative energy resources to substitute
petroleum. Vegetable oil can be one of the alternatives which can be used as fuel in automotive
engines. Changing the chemistry of fuel by adding the vegetable oil or completely replacing the
traditional fuels by the vegetable oil is being experimented.
Vegetable oils such as mustered oil, sunflower oil, cotton seed oil, canola oil, peanut oil, coconut
oil, and waste vegetable oil have been considered as alternative fuels for CI Engines. Kinematic
viscosity, specific gravity, cetane number, and pour and cloud points of these oils are much
higher than those of diesel. Therefore, such oils, in pure or blended form, cannot be used as fuel
in engines for long run.
In this study, oils from various feedstocks have been transesterified due to which their specific
gravity and kinematic viscosity were decreased and pour and cloud points were increased. The
chemical and physical properties of chemically modified oils, called biodiesel or methyl ester,
were tested in accordance with ASTM D6751 and found comparable to those of diesel.
The engine performance and emissions were evaluated using biodiesel in pure and blended form
and it was concluded that a blend of 20% waste vegetable oil methyl ester and 80% diesel (W20)
could be successfully used as an alternative fuel, in CI engine. Although higher brake specific
fuel consumption of W20 was observed, yet the fuel was found to be environmental friendly.
Reduced amount of THC and CO were found in the exhaust emissions of the engine. However,
level of NO x was increased.
To reduce NO x , certain modifications in the fuel injection system of the engine were made and
results were obtained by running the engine using W20 fuel. The experimental results showed
that engine performance was not much affected and engine emitted lower amount of NO x ,
without much affecting THC, and CO emissions.
