Combustion, performance and emissions of a diesel power generator with direct injection of B7 and port injection of ethanol

This work investigates a diesel engine operating with diesel oil containing 7% biodiesel (B7) and hydrous ethanol with concentrations varying from 5 to 30%. The experiments were conducted in a 49-kW diesel power generator, equipped with an electronic ethanol injection unit installed in the intake manifold and without any modifications in the diesel oil injection system. The results showed a decrease of in-cylinder pressure and net heat release rate with the use of ethanol at low loads and an increase at high loads, in comparison with B7. Increasing ethanol injection caused increased ignition delay and decreased combustion duration. Fuel conversion efficiency was raised up to 13% with the use of ethanol. The use of 30% ethanol in the fuel caused a reduction of carbon dioxide (CO2) emissions up to 12% and nitric oxide up to 53%. Carbon monoxide, total hydrocarbons and oxides of nitrogen (NOX) emissions increased with ethanol addition. The replacement of 20% of diesel fuel by ethanol showed the lowest penalties on NOX emissions.