Performance evaluation of diesel engine using biodiesels from waste coconut, sunflower, and palm cooking oils, and their hybrids

Modern food industries are using cooking oils in the blended/hybrid form to improve fried food's nutritional quality and taste. In the current study, biodiesels were produced from waste cooking oils of coconut, sunflower, and palm oils and their three mixtures in a 50:50 blending ratio. Fatty acid profile and properties such as density, kinematic viscosity, calorific value, cloud point, pour point, flash point, fire pint, copper strip corrosion, and carbon residue were compared for all six biodiesels. Later, the performance, combustion, and emission characteristics of a diesel engine operating with B20 blends of the six biodiesels were compared. The addition of coconut content reduced the density by 5.4 kg/m(3) and 0.7 kg/m(3) and kinematic viscosity by 0.837 cSt and 0.923 cSt, improved brake thermal efficiency of the engine at rated load by 0.15 % and 0.1 %, and reduced NOx emission by 25 ppm and 21 ppm, and smoke opacity by 8.5 % and 7.9 % for the sunflower and palm biodiesels, respectively. The pour point of palm-based biodiesel was reduced by 8 degrees C and 9 degrees C with the addition of coconut and sunflower oil contents. Therefore, hybridization improves the properties of the biodiesels and the performance and emission characteristics of diesel engines.