Page 283 - Biosystems Engineering

Biodiesel and Ethanol in Engines 261

800

700 Diesel
Putranjiva oil
Karanja oil
600 Jatropha oil
BSFC (g/kWh) 500

400

300

200
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Brake power (kW)
FIGURE 8.2 Brake-specifi c fuel consumption versus brake power of diesel
fuel, 100 percent biodiesel of Jatropha, karanja, and putranjiva at 1200 rpm,
45° angle before top dead centre (bTDC), and 20 compression ratio.

loads for different fuels. The torque increased with increase in load.
This was due to an increase in fuel consumption with an increase in
load. Mathur and Das conducted tests on diesel engines using
25
blends of mahua and neem oil with diesel. From the results Mathur
25
and Das concluded that neem oil could be substituted at 35 percent
with a marginal reduction in efficiency and power output. Mahua oil
with diesel had exhaust characteristics similar to those of diesel. The
performance of three transesterified vegetable oils and diesel are
shown in Fig. 8.2. It is observed that 100 percent methyl ester of Jatro-
pha, karanja, and putranjiva oil gives higher performance in brake-
specific fuel consumption (BSFC) and lower in brake thermal efficiency
(η ) than diesel at all loads. Transesterified karanja oil (100 percent)
bt
is more efficient than putranjiva and Jatropha, whereas Jatropha is
better in BSFC. At high loads the performance of the three biodiesels
is almost the same but is different from diesel.

8.1.6 Comparison of the Effect of Load on Biodiesel
Emission
The NO of biodiesel is lower than diesel, which is due to biodiesel’s
x
low CN. 26,27 The NO of biodiesel is increased slightly with load,
x
whereas diesel fuel shows a steady increase throughout the load.
With increasing load, the fuel consumption rate is increased and more