A comparative evaluation of Al2O3 coated low heat rejection diesel engine performance and emission characteristics using fuel as rice bran and pongamia methyl ester

In this study, for the first time, a nanoceramic Al2O3 was used as a coating material in the low heat rejection engine concept. Experiments were conducted on single cylinder, four stroke, water cooled, and direct injection diesel engine. First, the engine was tested at different load conditions without coating. Then, combustion chamber surfaces (cylinder head, cylinder liner, valves, and piston crown face) were coated with nanoceramic material of Al2O3 using plasma spray method. Comparative evaluation on performance and emission characteristics using fuel as rice bran methyl ester, pongamia methyl ester, and biodiesel/diesel fuel mixtures was studied in the ceramic coated and uncoated engines under the same running conditions. An increase in engine power and a decrease in specific fuel consumption, as well as significant improvements in exhaust gas emissions (except NOx) and smoke density, were observed in the ceramic coated engines compared with those of the uncoated engine.