Abstract
Due to increases in energy demand and depletion of non-renewable energy resources, researchers have been focused on finding an alternative fuel that can be used in compression ignition (CI) engines. In this paper, used transformer oil (UTO) was used as a fuel in a CI engine. Different properties were analysed and compared with diesel and it was found that this fuel can be used as a fuel for a CI engine without any engine modification. However, UTO has a higher viscosity than diesel fuel, so two different methods were used to overcome the viscosity of UTO. In the first method, UTO was preheated by exhaust gas, and in the second method it was esterified.