Abstract:
Diversity of fuels used in internal combustion engines can enhance the energy
security of power generation. A number of efforts have been made with alternative
fuels which can partly replace the use of diesel. Engines with such option are known
as dual fuel engines, i.e. they use conventional diesel fuel and a replacement gaseous
fuels simultaneously. Liquefied petroleum gas has a number of technical advantages
in this regard. The higher auto-ignition temperature and heating value, better
emission characteristics, as well as easy availability and portability makes LPG a
good candidate for such diesel supplements. Extraction of Natural gas Liquids in a
number of gas fields in Bangladesh has enhanced the prospects of LPG production of
the country.
In this research work, an experimental investigation was conducted on a single
cylinder water cooled DI Diesel engine, which was properly modified to operate
under LPG-Diesel fumigated fuel conditions, using maximum possible diesel
replacement by LPG at rated speed. First stage of this work examined the effect of
dual fuel combustion on different engine parameters like diesel replacement, exhaust
temperature, thermal efficiency and BSFC. The study revealed that only limited
diesel replacement with better thermal efficiency could be achieved by LPG near
rated load, while replacement rates improved in part loads. In the second stage, the
investigation was extended to explore the effect of increased and decreased injection
timing from the default configuration on those parameters. At higher loads the
default setting was found to be most efficient but at part loads, injection timing with
increased configuration showed best performance. The cost analysis of fuels during
the experiments showed that reduction of LPG price by more than 41% would make
it feasible for replacing diesel.
