Effect of thermal barrier coating on performance and emission characteristics of kapok oil methyl ester in diesel engine

This paper presents the observations of an experimental work carried out to study the impact of thermal barrier coating on direct injection (DI) diesel engine. This work also evaluates the performance and emission characteristics of kapok oil biodiesel blended with traditional diesel in a DI diesel engine. Biodiesel obtained from kapok seed oil using the transesterification process was termed as kapok oil methyl ester (KOME). Three fuel samples were prepared, namely B1 (25% KOME with 75% diesel), B2 (50% KOME with 50% diesel) and B3 (75% KOME with 25% diesel). The combustion chamber components like piston head, cylinder head and intake and exhaust valves were coated with 50 μm of NiCrAl and 450 μm of yttria stabilised zirconia (Y₂O ZrO₂). The coated engine showed higher brake thermal efficiency (BTE) and brake-specific fuel consumption (BSFC) than the uncoated engine. Among the fuel samples, diesel and B1 showed a similar trend of increasing BTE with decreased BSFC. The coated engine showed lower CO, HC and smoke emissions than the uncoated engine. In the coated engine, B1 exhibited lower CO, HC and smoke emissions except NOx than other fuel samples.