Investigation of the effects of organic based manganese addition to biodiesel on combustion and exhaust emissions

• Organic-based manganese fuel additive was used in a diesel engine.
• Combustion, performance and emission characteristics were examined.
• Engine torque increased up to 6.5% when 12 μmol/l additive was used.
• Specific fuel consumption decreased 6.87% using RMEMn12 fuel.
• CO, HC and smoke emissions decreased while NOx emissions increased partially.

The use of biofuel as an energy alternative has gain continuous increase over the years; this is due to their advantage in limiting global warming and harmful emissions arising from diesel engines; this couple with the fast dwindling rate of fossil fuels has increased attention towards their uses. Studies have been conducted in recent years to analyze different energy sources and fuel additives for diesel engines. In this study, the combustion and emission characteristics were investigated by adding organic based manganese additive into rapeseed methyl ester (R0) in four (4) different loads. The results showed that there was a decrease in the viscosity, density, and flash point of fuels treated with additives while the calorific value of the treated fuel was increased. These improvements in the fuel features enhanced the fuel atomization. A minimum ignition delay was obtained in the R0Mn12 fuel for all the loads. A fuel ignition delay of 13.21 °CA occurred in the maximum load, while the maximum cylinder pressure of 62.76 bar was recorded. As a result of enhancing the fuel characteristics, analysis of the combustion emission revealed a reduction of 25.28% in carbon monoxide (CO), 6.64% in total hydrocarbon (THC), 6.5% in smoke emission and 25.52% increase of nitrogen oxides (NOx) were recorded in the R0Mn12 fuel compared to the R0 fuel.