Performance of a compression ignition engine using LPG-diesel dual fuel

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.