Optimization of FOME (fish oil methyl esters) blend and EGR (exhaust gas recirculation) for simultaneous control of NOx and particulate matter emissions in diesel engines

There is world-wide interest in the search for alternatives to petroleum derived fuels for diesel engines. Key driving factors are depleting fossil-fuel reserves all over the globe as well as the environmental impact of burning fossil fuels that cause pollution and global warming. Bio-diesel derived from edible oils, non-edible oils and animal fats can be used in diesel engines with little or no modification. Non-land-based renewable sources are becoming important for the production of biodiesel due to limited availability of land. Under these circumstances, fish oil extracted from wastes of processed marine fish and refined through transesterification becomes an attractive alternative for the production of biodiesel. In this work, performance and emission characteristics of FOME (fish oil methyl ester) and its blends are evaluated in a direct-injection single-cylinder constant-speed diesel engine primarily used in the agricultural sector. It is seen that 20% FOME blend gives almost the same brake thermal efficiency with lower unburned hydrocarbons, carbon monoxide and soot emissions but higher NOx (nitrogen oxides) emissions compared to diesel fuel. EGR (Exhaust Gas Recirculation) is used to control NOx emissions. Percentage of EGR is varied to determine optimum EGR for 20% FOME blend. •Combustion analysis of FOME (fish oil methyl esters) and its blends is presented.•CO, UBHC (unburned hydrocarbons) and PM (particulate matter) emissions are lower than those of diesel at all loads.•NOx (nitrogen oxides) emissions are higher at all loads.•Optimum percentage of blend is found to 20% FOME.•20% EGR (exhaust gas recirculation) is found to be optimum for 20% FOME.