Abstract
The fuel demand rise coupled with its harmful emissions has contributed to the continuous search of substitute for diesel oil. This research intended to improve the diesel engine performance, combustion characteristics and emissions supplied with biodiesel from waste cooking oil (WCO) enriched with carbon nanotubes and graphene nano sheet. Biodiesel properties were measured and agreed with ASTM standards. Biodiesel blend was obtained by blending of 20% volume percentage of biodiesel to diesel oil as B20. Different concentrations as 25, 50 and 100 ppm of CNTs and graphene nano sheets were mixed with biodiesel blend. Surfactant of 2% was added to the nanofluid to achieve the higher stability and dispersion. The maximum improvements in thermal efficiency for B20CNT100 and B20CNS100 were 8 and 19%, respectively about B20. Biodiesel blend with CNTs and graphene nano sheet concentrations of 100 ppm achieved the highest decreases in smoke emissios by 28 and 54% but the maximum decreases in CO emission were 27 and 47%, respectively about B20. The maximum reductions in NOx emissions were 22 and 44% but in HC emission for B20CNT100 and B20CNS100 were 28 and 52%, respectively about biodiesel blend. The highest ignition delay decreases were 10 and 22%, respectively but the peak cylinder pressures improvements were 3 and 5.5%, respectively for B20CNT100 and B20CNS100 in comparison to B20. Biodiesel blend with graphene nano sheet additive with concentration of 100 ppm was recommended to show the improvements in combustion characteristics, performance and emissions reduction as compared to the biodiesel blend.