Investigation on influence of thermal barrier coating on diesel engine performance and emissions in dual-fuel mode using upgraded biogas

In the present investigation, we used semidried banana leaves to produce biogas through anaerobic digestion where the methane content in biogas reached up to 87% via a scrubber fabricated with packed bed iron chips for removal of carbon dioxide and hydrogen sulphide. The diesel engine was converted to run in dual-fuel mode under variation of biogas flow rate at different engine loads. Yttria stabilized zirconia was used as thermal barrier coating (TBC) on piston crown and valves to improve the performance of dual-fuel engine. It was observed that engine with TBC has shown an improved combustion and performance characteristics for dual-fuel operation with reduction in exhaust emissions. The brake thermal efficiency at full load operation is decreased by 23, 29 and 34% for uncoated engine with induction of biogas at 0.6, 0.8 and 1 kg h− 1, respectively, while this decrease is minimized to 10, 12 and 19% for coated engine at the corresponding flow rates with respect to base result. In uncoated engine the carbon monoxide emission at highest engine load is increased by 35, 35 and 40% of the respective biogas flow rates, while in coated engine, the percentage of increase is reduced to 25, 28 and 33% as compared to diesel mode operation. Similar trends were observed for unburnt hydrocarbon emissions, while nitric oxide emissions increased for coated engine in both modes of operation.