This book analyze the performance and emission characteristics of vegetable oil, its blends with diesel, the same in preheated condition, biodiesel and its blend with diesel in CI engines. Thermal cracking of vegetable oil for CI engine application is also studied. The physical and chemical properties of the above test fuels were also studied. This book also attempts an experiment to use gasified Pongamia oil as a fuel for CI engine application. The results of TGA and the gasified products of Pongamia oil at various temperature were positive and their results were reported.Viscosity plays an important role in combustion process. Most vegetable oils were about ten times viscous than diesel. Due to the high-viscous property of vegetable oil, the atomization of fuel is poor when compared to diesel. This leads to poor combustion quality and reduced efficiency. Many authors have followed different methods to reduce the viscosity of vegetable oil. Some of the methods were: Blending of vegetable oil with lesser viscous fluids, transesterification, preheating and thermal cracking. There are certain advantages and disadvantages over the above methods.
