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402 Advances in Eco-Fuels for a Sustainable Environment
60
50
Smoke (HSU) 40 Diesel
A20
30
A40
20 A60
A80
10
A100
0
0 1 2 3 4 5 6
BP (kW)
Fig. 14.8 Variation of Smoke with BP for diesel and different proportions of AME diesel
blends.
Fig. 14.8 shows the variation of smoke emissions with brake power for different
proportions of AME diesel blends and diesel. It is seen that the smoke decreases with
increasing brake power for all blends at all loads. Among the different blends, A20 has
lower smoke than that of other blends. The smoke for A20 is 17.8HSU and for diesel is
18.8HSU at maximum load. This is due to the higher oxygen content in biodiesel
enhancing combustion and reducing smoke emissions. Even though the oxygen con-
tent increases with increasing the blend ratio, the smoke intensity also increases
because of incomplete combustion due to the low calorific value of other biodiesel
blends.
14.3.4.5 Combustion characteristics for AME-diesel blends
In the present investigation, the experiments for combustion parameters such as cyl-
inder pressure and heat release rate for different proportions of AME-diesel blends.
14.3.5 Cylinder pressure
Fig. 14.9 shows the variation of cylinder pressure with crank angle for different pro-
portions of AME-diesel and diesel at full load. The cylinder peak pressure of AME-
diesel blends is lower than that of diesel because of high viscosity and poor volatility.
It is observed from Fig. 14.9 that the peak cylinder pressure for diesel is 75bar and
A20 is 65bar. It is found that peak cylinder pressure is higher for diesel than that
of AME-diesel blends and decreases with increasing the percentage of proportions
of biodiesel. This is due to the shorter ignition delay and less fuel/air mixture present
in the combustion at the time of ignition and thereby more burning in the diffusion-
burning phase than that of the premixed burning phase. This leads to a reduction in
cylinder peak pressure for biodiesel-diesel blends.
