Performance and emission tests of biodiesel fuels using a conventional diesel engine

Abstract

The use of palm oil-based biodiesel fuel has been proposed as an alternative fuel for diesel engines in Malaysia. The main purpose of this study is to investigate the performance and exhaust emissions of several biodiesel blends of neutralized palm oil methyl ester (NPOME) in a small-unmodified direct injection diesel engine, and to compare them to that of a Malaysian grade 2 diesel fuel (D2). Experimental measurements of engine performances, exhaust emissions, cylinder pressure, fuel line pressure, rate of heat release and ignition delay were performed as a function of engine load at different engine speeds. Comparisons between D2 and the biodiesel blends on the brake specific fuel consumption (BSFC), brake thermal efficiency, heat release, cylinder pressure, ignition delay, carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxide (NOx), unburned hydrocarbon (uHC), particulate matter (PM) and exhaust smoke were carried out in this study. A comparison between D2 and the biodiesel fuels on the injector tip deposit was also studied. In this study, simulations were performed to evaluate the diesel and biodiesel fuels performance in a diesel engine. The simulation was modelled using GT-Power software in order to simulate the performance and emissions. Based on the simulation, the results were comparable to the experimental results. In the engine experiment, it was found that the palm oil-based biodiesels behaved comparably to the D2 in terms of performance (fuel consumption and thermal efficiency) and rate of heat released. Smoke quality showed a better result when compared to that emitted by the diesel fuel (D2) operating under similar conditions. The injector tip deposit was lower when biodiesel fuels were used in the engine when compared to the diesel fuel (D2). The emissions of CO, CO2, HC and PM were also lower using biodiesel fuels, while NOx emissions were higher when compared to D2.