Behavior analysis of Low-Heat Rejection engine powered by biodiesel under varied exhaust gas recirculation ratios

Abstract

ABSTRACT The key focus areas of the internal combustion engine architecture are energy effectiveness and greater thermal efficiency since 1/3 of the produced heat energy vanishes on the way to the atmosphere and the coolant. Experiments have looked into the viability of using tamanu biodiesel in a thermally insulated diesel engine. The engine was first put through its paces on regular diesel fuel as a comparison baseline. After that, the piston, exhaust, intake valve and cylinder head surfaces were coated with partially stabilized zirconia (PSZ) to act as thermal insulation for the engine. The engine coating was developed to improve the efficiency of the engine’s use of biodiesel blends by decreasing heat loss through the chamber walls with a thickness of 200 micrometers (µm). In addition, mixes of Tamanu biodiesel with diesel fuel were tested, including B10, B20, B30, and B100, to examine how these mixtures would influence the performance of the ceramic-coated low heat rejection (LHR) engine compared to the performance of the base diesel engine. Additionally, the impacts of different exhaust gas recirculation (EGR) ratios on the operation of biodiesel-powered LHR engines were analyzed. The zirconia insulated LHR engine running on B20 performed the best, with a thermal efficiency of 28.57% and a brake specific energy consumption that was considerably lower than that of the baseline diesel engine. In addition, the LHR engine for B20 reduces carbon monoxide (CO) and smoke emissions by 17% and 21.4%, respectively, compared to the B20-powered base diesel engine, although nitrogen oxide (NOx) emissions slightly increase. However, the addition of 15% EGR to the B20-LHR engine produced a minor increment in hydrocarbon (HC), CO and smoke emissions, corresponding to 19.7% and 25.4%, respectively. By implementing 15% EGR with B20-LHR, the NOx level is reduced by 25.4% due to diluting the air-fuel mixture. The combination of 15% EGR with B20 for a thermal barrier-coated engine offers significant improvement by increasing engine performance and reducing emission characteristics.