Effect of fuel preheating with blended fuels and exhaust gas recirculation on diesel engine operating parameters

This study investigates the influence of preheating on fuel properties of biodiesel and its blends on the performance of a diesel engine. Subsequently, the effectiveness of exhaust gas recirculation (EGR) rate for reducing the NOx emission has also been explored. At 102 °C, fuel-preheating temperature, the average percentage reductions of kinematic viscosity and density of JOME was 49% and 4.3%, respectively with decrease (17.4%) in brake specific fuel consumption (BSFC) and increase (23%) of brake thermal efficiency (BTHE). The comparative study of all fuels with diesel revealed the fact that the blended fuel (40% biodiesel - 40PBD) with preheating (102 °C), is seen to be most efficient when operated without EGR mode. At full load engine testing with same test fuel, BSFC reduces by 19%, BTHE increases by 16%, the exhaust gas temperature (EGT) drops by 6% with slight increase in volumetric efficiency (2%). The carbon monoxide and unburned hydrocarbon emission was reduced by 19.5% and 4.8%, respectively while oxides of nitrogen (NOx) emission was increased by 17.5% compared to diesel fuel. The inclusion of the EGR rate of 30% for 40PBD test fuel, meaningfully decreases the average NOx emission by 68.8% with almost insignificant change in engine BSFC and BTHE.