A Comparative Assessment on Performance and Emissions Characteristics of a Diesel Engine Fumigating with Methanol, Methyl Ethyl Ketone, and Liquefied Petroleum Gas

This study has investigated the influence of partial premixing fumigation of the intake air with light fuels (LF), methanol, methyl ethyl ketone (MEK), and liquified petroleum gas on the engine performance and the emissions. Exhaust emissions of oxides of nitrogen (NOx), carbon monoxide (CO), and unburnt hydrocarbon (UHC), and smoke density were measured and quantified. The experimental study was carried out in a single cylinder diesel engine. The experimental set-up for liquid fuel fumigation is such that the known quantity of methyl ethyl ketone is fumigated in the intake manifold using a microprocessor-controlled electronic fuel injector, and for gaseous fuel, liquefied petroleum gas is admitted into the intake manifold through a flow meter. The results of this study showed an appreciable reduction of emissions, such as oxides of nitrogen, smoke density with an increased amount of CO and HC for all fuels at fumigation mode, and a significant increase in performance during liquid fuel fumigation than liquefied petroleum gas. Emissions reductions of 48% NOx and 25% smoke density were observed for methanol fumigation whereas the reductions were 42 and 34% for MEK and a maximum of 48 and 66% for liquefied petroleum gas induction. The increase in HC emissions was 20 and 3% for methanol and MEK, respectively, at full load where it was very high for liquefied petroleum gas induction. Similarly, a maximum increase of 66% of CO for liquefied petroleum gas induction was recorded against 22% for light fuel mixtures at full load. A maximum of 7% increase in brake thermal efficiency for methanol fumigation was recorded against 3% for MEK, while 8% reduction for liquefied petroleum gas induction.