dc.description.abstract |
Compression ignition (CI) engines are widely used all over the world and are associated
with higher fuel conversion efficiency, power output, torque output, durability, and
reliability over spark ignition (SI) engines. However, there is the rapid depletion of
fossil fuel reserves which has necessitated a search for alternative fuels for CI engines.
Consequently, the main objective of this study was to optimize the performance of
compression ignition engines fueled by ternary blends of diesel, biodiesel and propanol.
The study’s specific objectives included the production of ternary blends, investigation
of engine performance under varying blend concentrations and determination of the
optimal blend concentration that minimizes emissions of pollutant gases. In this study,
biodiesel was produced from waste vegetable oil through trans-esterification process
and was blended with commercial diesel and propanol in ratios of 0% to 25%, 75% to
100% and 0% to 5%, respectively. The physical parameters of the ternary blends, such
as density and viscosity, were determined and blends were used to run a 16.8-kilowatt
Petter's two-cylinder engine running at a constant engine speed of 2000 rpm and brake
power of 10 kilowatts. The desirability technique was used to determine the optimal
values, which included minimizing nitrogen oxide (NOx), hydrogen oxide (HC), and
carbon monoxide (CO) emissions while maximizing brake thermal efficiency (BTE).
Using design expert software, the experiment was carried out via the response surface
method (RSM). Responses included brake thermal efficiency, brake specific fuel
consumption (BSFC), emissions of nitrogen oxide, hydrogen oxide, and carbon
monoxide, and the variables were blended from diesel, biodiesel, and propanol. Gas
emissions from the optimal blend were measured using exhaust gas detectors. Five
solutions with desirability ranging from 0.667% to 0.828% were discovered. They each
had unique blend proportions and responses. The optimal combination with 0.828
desirability was deemed the best. The blend of 75.01%, 24.604%, and 0.386% was
found to be optimal, with responses of BTE 63.001%, BSFC 0.153kg/kWh, and
emissions of NOx 82.347 ppm, CO 436.013 ppm, and HC 4.877 ppm, and physical
properties of 0.972 g/cm3 density and viscosity of 4.363 cP. BTE increased by 9%
when compared to pure diesel with a density of 0.96 g/cm3 and a viscosity of 6 cP,
while BSFC, NOx, CO, and HC decreased by 15%, 12.87%, 15.23%, and 75%,
respectively. Different blends have different physical attributes, like density and
viscosity, which affected engine performance. There was no direct relationship between
the two properties. No phase separation was observed in the blends. Based on the
results, the optimal ternary blend of diesel, biodiesel, and propanol is recommended for
internal combustion engines due to notable improvements in engine performance and
reduced emissions. Additionally, we recommend that future studies investigate the
long-term effects of using ternary fuel blends on engine components. This could be
done by conducting durability tests and monitoring emissions over extended periods of
use. In addition, we recommend that future research also investigate the possibility of
using other biofuels such as bioethanol or biogasoline in the ternary blend, to see if they
could also improve engine performance, emissions, and fuel consumption. However,
further research is required to establish the life span of the optimal blend and to
determine if its efficiency decreases over time. |
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