Thermal Energy Balance of an Otto Cycle Engine Fueled with Ethanol and Gasoline

Otto Cycle can operate with both gasoline and ethanol; however, these fuels have different properties that will result in different performance parameters. This work aims to compare the thermal energy balance of an internal combustion engine fueled with gasoline and ethanol. The experimental tests were carried out on a dynamometer bench varying engine speed between 1500 and 6000 rpm and at full load condition. The results showed that the engine’s maximum thermal efficiency ranged from 30.51% with gasoline to 31.72% with ethanol. The percentage of energy dissipated to the cooling system varied from 16.93% with gasoline from 16.12% with ethanol. The percentage of energy dissipated to the exhaust system ranged from 32.82% with gasoline from 34.64% with ethanol. The percentage of energy wasted due to incomplete fuel combustion varied from 3.50% with gasoline from 10.00% with ethanol. The percentage of energy dissipated to the lubrication system ranged from 3.95% with gasoline from 3.76% with ethanol. The percentage of energy rejected into the environment by convection and radiation heat transfer ranged from 30.43% with gasoline from 27.96% with ethanol. This work is relevant because a detailed study of the thermal energy balance in an internal combustion engine operated with ethanol and gasoline was carried out.