Page 448 - Advances in Eco-Fuels for a Sustainable Environment

Assessment of performance and emission behavior of novel annona 401

for diesel is 0.04% at maximum load. This is due to a higher oxygen content in the
biodiesel blends that enhances the complete combustion and leads to a reduction in
the CO emissions. The diesel fuel has a higher CO emission than that of AME-diesel
blends because there is a lack of oxygen present in the diesel fuel. The CO emission
increases with an increase in the biodiesel proportion due to high viscosity, which
leads to poor atomization, a less homogenous mixture, and uneven distribution of
small portions of fuel in the combustion chamber.

14.3.4.3 NO x emission
NO x emission is found in an engine due to higher in-cylinder temperature. Though the
diesel fuel or the ester-based biodiesel does not contain nitrogen, the NO x are formed
by taking the nitrogen from the air because 78% of nitrogen is present in the air.
Fig. 14.7 shows the variation of NO x emission with brake power for different pro-
portions of AME diesel blends and diesel. It is noted that the NO x increases with
increasing brake power for all AME-diesel blends at all loads. Among the different
AME-diesel blends, A20 has a lower NO x emission than that of other blends. The
NO x for A20 is 620ppm and for diesel is 552ppm at maximum load. The diesel fuel
has less NO x emission because the diesel fuel contains no oxygen content. When the
biodiesel is present in the combustion chamber, the temperature becomes very high
due to the presence of higher oxygen content, which enhances combustion and results
in higher NO x emission.

14.3.4.4 Smoke emission

Smoke is emitted in a CI engine, an unwanted byproduct of combustion that is formed
due to incomplete combustion of hydrocarbon fuel. The smoke emission depends on
the type of fuel and the nature of the operating conditions.

900
800
700
Diesel
600
NO X (ppm) 500 A20
A40
400
A60
300
A80
200
A100
100
0
0 1 2 3 4 5 6
BP (kW)
Fig. 14.7 Variation of NO x with BP for diesel and different proportions of AME diesel blends.