Utilization of RSM to optimize the performance and emissions of a single cylinder diesel engine using waste hazelnut biodiesel

Abstract

One of the environmentally friendly, biodegradable, and renewable alternative fuels widely used around the world is biodiesel. Among vegetable oils, hazelnut oil has great importance in biodiesel production due to its high content of oleic acid. For this study, it is aimed to determine the optimum mixing ratio of biodiesel, produced from waste hazelnut oil (WHB). The tests were carried out on a diesel engine operated with WHB/diesel mixtures at different loads. By means of the design of experimental method (DOE), three different fuel ratios (WHB0, WHB15 and WHB30) were defined and tests have been performed. The results obtained from the tests were analyzed using the response surface method (RSM). Engine load and mixing ratio were determined as input factors while CO, NOx, smoke, indicated thermal efficiency (ITE), ignition delay (ID) and break specific fuel consumption (BSFC) were determined as output factors. In the mathematical model created, the R2 values were found to be 0.98, 0.95, 0.91, 0.98, 0.99 and 0.90 respectively. The high R2 values indicated a strong correlation between the optimization outputs and the real experiments. By using these performance and emission parameters, optimization was performed to identify the optimum blend ratio and load. Based on the results, the optimum inputs were determined as 8.46 Nm load and 4.86 % blend ratio. As a result, with the optimized fuel blend, BSFC (8.03 %), ID (3.57 %), and NO (2.87 %) increased while ITE (7.7 %), CO (18.37 %), and smoke (26.15 %) decreased comparing to WHB0. Despite the slight increase in consumption, the results showed that this blend could be used in an environmentally efficient manner, thanks to the reduction in pollutant emissions.